Git 1.8.5.1
[git] / remote.c
1 #include "cache.h"
2 #include "remote.h"
3 #include "refs.h"
4 #include "commit.h"
5 #include "diff.h"
6 #include "revision.h"
7 #include "dir.h"
8 #include "tag.h"
9 #include "string-list.h"
10 #include "mergesort.h"
11
12 enum map_direction { FROM_SRC, FROM_DST };
13
14 static struct refspec s_tag_refspec = {
15         0,
16         1,
17         0,
18         0,
19         "refs/tags/*",
20         "refs/tags/*"
21 };
22
23 const struct refspec *tag_refspec = &s_tag_refspec;
24
25 struct counted_string {
26         size_t len;
27         const char *s;
28 };
29 struct rewrite {
30         const char *base;
31         size_t baselen;
32         struct counted_string *instead_of;
33         int instead_of_nr;
34         int instead_of_alloc;
35 };
36 struct rewrites {
37         struct rewrite **rewrite;
38         int rewrite_alloc;
39         int rewrite_nr;
40 };
41
42 static struct remote **remotes;
43 static int remotes_alloc;
44 static int remotes_nr;
45
46 static struct branch **branches;
47 static int branches_alloc;
48 static int branches_nr;
49
50 static struct branch *current_branch;
51 static const char *default_remote_name;
52 static const char *pushremote_name;
53 static int explicit_default_remote_name;
54
55 static struct rewrites rewrites;
56 static struct rewrites rewrites_push;
57
58 #define BUF_SIZE (2048)
59 static char buffer[BUF_SIZE];
60
61 static int valid_remote(const struct remote *remote)
62 {
63         return (!!remote->url) || (!!remote->foreign_vcs);
64 }
65
66 static const char *alias_url(const char *url, struct rewrites *r)
67 {
68         int i, j;
69         char *ret;
70         struct counted_string *longest;
71         int longest_i;
72
73         longest = NULL;
74         longest_i = -1;
75         for (i = 0; i < r->rewrite_nr; i++) {
76                 if (!r->rewrite[i])
77                         continue;
78                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
79                         if (!prefixcmp(url, r->rewrite[i]->instead_of[j].s) &&
80                             (!longest ||
81                              longest->len < r->rewrite[i]->instead_of[j].len)) {
82                                 longest = &(r->rewrite[i]->instead_of[j]);
83                                 longest_i = i;
84                         }
85                 }
86         }
87         if (!longest)
88                 return url;
89
90         ret = xmalloc(r->rewrite[longest_i]->baselen +
91                      (strlen(url) - longest->len) + 1);
92         strcpy(ret, r->rewrite[longest_i]->base);
93         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
94         return ret;
95 }
96
97 static void add_push_refspec(struct remote *remote, const char *ref)
98 {
99         ALLOC_GROW(remote->push_refspec,
100                    remote->push_refspec_nr + 1,
101                    remote->push_refspec_alloc);
102         remote->push_refspec[remote->push_refspec_nr++] = ref;
103 }
104
105 static void add_fetch_refspec(struct remote *remote, const char *ref)
106 {
107         ALLOC_GROW(remote->fetch_refspec,
108                    remote->fetch_refspec_nr + 1,
109                    remote->fetch_refspec_alloc);
110         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
111 }
112
113 static void add_url(struct remote *remote, const char *url)
114 {
115         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
116         remote->url[remote->url_nr++] = url;
117 }
118
119 static void add_pushurl(struct remote *remote, const char *pushurl)
120 {
121         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
122         remote->pushurl[remote->pushurl_nr++] = pushurl;
123 }
124
125 static void add_pushurl_alias(struct remote *remote, const char *url)
126 {
127         const char *pushurl = alias_url(url, &rewrites_push);
128         if (pushurl != url)
129                 add_pushurl(remote, pushurl);
130 }
131
132 static void add_url_alias(struct remote *remote, const char *url)
133 {
134         add_url(remote, alias_url(url, &rewrites));
135         add_pushurl_alias(remote, url);
136 }
137
138 static struct remote *make_remote(const char *name, int len)
139 {
140         struct remote *ret;
141         int i;
142
143         for (i = 0; i < remotes_nr; i++) {
144                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
145                            !remotes[i]->name[len]) :
146                     !strcmp(name, remotes[i]->name))
147                         return remotes[i];
148         }
149
150         ret = xcalloc(1, sizeof(struct remote));
151         ret->prune = -1;  /* unspecified */
152         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
153         remotes[remotes_nr++] = ret;
154         if (len)
155                 ret->name = xstrndup(name, len);
156         else
157                 ret->name = xstrdup(name);
158         return ret;
159 }
160
161 static void add_merge(struct branch *branch, const char *name)
162 {
163         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
164                    branch->merge_alloc);
165         branch->merge_name[branch->merge_nr++] = name;
166 }
167
168 static struct branch *make_branch(const char *name, int len)
169 {
170         struct branch *ret;
171         int i;
172         char *refname;
173
174         for (i = 0; i < branches_nr; i++) {
175                 if (len ? (!strncmp(name, branches[i]->name, len) &&
176                            !branches[i]->name[len]) :
177                     !strcmp(name, branches[i]->name))
178                         return branches[i];
179         }
180
181         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
182         ret = xcalloc(1, sizeof(struct branch));
183         branches[branches_nr++] = ret;
184         if (len)
185                 ret->name = xstrndup(name, len);
186         else
187                 ret->name = xstrdup(name);
188         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
189         strcpy(refname, "refs/heads/");
190         strcpy(refname + strlen("refs/heads/"), ret->name);
191         ret->refname = refname;
192
193         return ret;
194 }
195
196 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
197 {
198         struct rewrite *ret;
199         int i;
200
201         for (i = 0; i < r->rewrite_nr; i++) {
202                 if (len
203                     ? (len == r->rewrite[i]->baselen &&
204                        !strncmp(base, r->rewrite[i]->base, len))
205                     : !strcmp(base, r->rewrite[i]->base))
206                         return r->rewrite[i];
207         }
208
209         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
210         ret = xcalloc(1, sizeof(struct rewrite));
211         r->rewrite[r->rewrite_nr++] = ret;
212         if (len) {
213                 ret->base = xstrndup(base, len);
214                 ret->baselen = len;
215         }
216         else {
217                 ret->base = xstrdup(base);
218                 ret->baselen = strlen(base);
219         }
220         return ret;
221 }
222
223 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
224 {
225         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
226         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
227         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
228         rewrite->instead_of_nr++;
229 }
230
231 static void read_remotes_file(struct remote *remote)
232 {
233         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
234
235         if (!f)
236                 return;
237         remote->origin = REMOTE_REMOTES;
238         while (fgets(buffer, BUF_SIZE, f)) {
239                 int value_list;
240                 char *s, *p;
241
242                 if (!prefixcmp(buffer, "URL:")) {
243                         value_list = 0;
244                         s = buffer + 4;
245                 } else if (!prefixcmp(buffer, "Push:")) {
246                         value_list = 1;
247                         s = buffer + 5;
248                 } else if (!prefixcmp(buffer, "Pull:")) {
249                         value_list = 2;
250                         s = buffer + 5;
251                 } else
252                         continue;
253
254                 while (isspace(*s))
255                         s++;
256                 if (!*s)
257                         continue;
258
259                 p = s + strlen(s);
260                 while (isspace(p[-1]))
261                         *--p = 0;
262
263                 switch (value_list) {
264                 case 0:
265                         add_url_alias(remote, xstrdup(s));
266                         break;
267                 case 1:
268                         add_push_refspec(remote, xstrdup(s));
269                         break;
270                 case 2:
271                         add_fetch_refspec(remote, xstrdup(s));
272                         break;
273                 }
274         }
275         fclose(f);
276 }
277
278 static void read_branches_file(struct remote *remote)
279 {
280         char *frag;
281         struct strbuf branch = STRBUF_INIT;
282         int n = 1000;
283         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
284         char *s, *p;
285         int len;
286
287         if (!f)
288                 return;
289         s = fgets(buffer, BUF_SIZE, f);
290         fclose(f);
291         if (!s)
292                 return;
293         while (isspace(*s))
294                 s++;
295         if (!*s)
296                 return;
297         remote->origin = REMOTE_BRANCHES;
298         p = s + strlen(s);
299         while (isspace(p[-1]))
300                 *--p = 0;
301         len = p - s;
302         p = xmalloc(len + 1);
303         strcpy(p, s);
304
305         /*
306          * The branches file would have URL and optionally
307          * #branch specified.  The "master" (or specified) branch is
308          * fetched and stored in the local branch of the same name.
309          */
310         frag = strchr(p, '#');
311         if (frag) {
312                 *(frag++) = '\0';
313                 strbuf_addf(&branch, "refs/heads/%s", frag);
314         } else
315                 strbuf_addstr(&branch, "refs/heads/master");
316
317         strbuf_addf(&branch, ":refs/heads/%s", remote->name);
318         add_url_alias(remote, p);
319         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
320         /*
321          * Cogito compatible push: push current HEAD to remote #branch
322          * (master if missing)
323          */
324         strbuf_init(&branch, 0);
325         strbuf_addstr(&branch, "HEAD");
326         if (frag)
327                 strbuf_addf(&branch, ":refs/heads/%s", frag);
328         else
329                 strbuf_addstr(&branch, ":refs/heads/master");
330         add_push_refspec(remote, strbuf_detach(&branch, NULL));
331         remote->fetch_tags = 1; /* always auto-follow */
332 }
333
334 static int handle_config(const char *key, const char *value, void *cb)
335 {
336         const char *name;
337         const char *subkey;
338         struct remote *remote;
339         struct branch *branch;
340         if (!prefixcmp(key, "branch.")) {
341                 name = key + 7;
342                 subkey = strrchr(name, '.');
343                 if (!subkey)
344                         return 0;
345                 branch = make_branch(name, subkey - name);
346                 if (!strcmp(subkey, ".remote")) {
347                         if (git_config_string(&branch->remote_name, key, value))
348                                 return -1;
349                         if (branch == current_branch) {
350                                 default_remote_name = branch->remote_name;
351                                 explicit_default_remote_name = 1;
352                         }
353                 } else if (!strcmp(subkey, ".pushremote")) {
354                         if (branch == current_branch)
355                                 if (git_config_string(&pushremote_name, key, value))
356                                         return -1;
357                 } else if (!strcmp(subkey, ".merge")) {
358                         if (!value)
359                                 return config_error_nonbool(key);
360                         add_merge(branch, xstrdup(value));
361                 }
362                 return 0;
363         }
364         if (!prefixcmp(key, "url.")) {
365                 struct rewrite *rewrite;
366                 name = key + 4;
367                 subkey = strrchr(name, '.');
368                 if (!subkey)
369                         return 0;
370                 if (!strcmp(subkey, ".insteadof")) {
371                         rewrite = make_rewrite(&rewrites, name, subkey - name);
372                         if (!value)
373                                 return config_error_nonbool(key);
374                         add_instead_of(rewrite, xstrdup(value));
375                 } else if (!strcmp(subkey, ".pushinsteadof")) {
376                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
377                         if (!value)
378                                 return config_error_nonbool(key);
379                         add_instead_of(rewrite, xstrdup(value));
380                 }
381         }
382
383         if (prefixcmp(key,  "remote."))
384                 return 0;
385         name = key + 7;
386
387         /* Handle remote.* variables */
388         if (!strcmp(name, "pushdefault"))
389                 return git_config_string(&pushremote_name, key, value);
390
391         /* Handle remote.<name>.* variables */
392         if (*name == '/') {
393                 warning("Config remote shorthand cannot begin with '/': %s",
394                         name);
395                 return 0;
396         }
397         subkey = strrchr(name, '.');
398         if (!subkey)
399                 return 0;
400         remote = make_remote(name, subkey - name);
401         remote->origin = REMOTE_CONFIG;
402         if (!strcmp(subkey, ".mirror"))
403                 remote->mirror = git_config_bool(key, value);
404         else if (!strcmp(subkey, ".skipdefaultupdate"))
405                 remote->skip_default_update = git_config_bool(key, value);
406         else if (!strcmp(subkey, ".skipfetchall"))
407                 remote->skip_default_update = git_config_bool(key, value);
408         else if (!strcmp(subkey, ".prune"))
409                 remote->prune = git_config_bool(key, value);
410         else if (!strcmp(subkey, ".url")) {
411                 const char *v;
412                 if (git_config_string(&v, key, value))
413                         return -1;
414                 add_url(remote, v);
415         } else if (!strcmp(subkey, ".pushurl")) {
416                 const char *v;
417                 if (git_config_string(&v, key, value))
418                         return -1;
419                 add_pushurl(remote, v);
420         } else if (!strcmp(subkey, ".push")) {
421                 const char *v;
422                 if (git_config_string(&v, key, value))
423                         return -1;
424                 add_push_refspec(remote, v);
425         } else if (!strcmp(subkey, ".fetch")) {
426                 const char *v;
427                 if (git_config_string(&v, key, value))
428                         return -1;
429                 add_fetch_refspec(remote, v);
430         } else if (!strcmp(subkey, ".receivepack")) {
431                 const char *v;
432                 if (git_config_string(&v, key, value))
433                         return -1;
434                 if (!remote->receivepack)
435                         remote->receivepack = v;
436                 else
437                         error("more than one receivepack given, using the first");
438         } else if (!strcmp(subkey, ".uploadpack")) {
439                 const char *v;
440                 if (git_config_string(&v, key, value))
441                         return -1;
442                 if (!remote->uploadpack)
443                         remote->uploadpack = v;
444                 else
445                         error("more than one uploadpack given, using the first");
446         } else if (!strcmp(subkey, ".tagopt")) {
447                 if (!strcmp(value, "--no-tags"))
448                         remote->fetch_tags = -1;
449                 else if (!strcmp(value, "--tags"))
450                         remote->fetch_tags = 2;
451         } else if (!strcmp(subkey, ".proxy")) {
452                 return git_config_string((const char **)&remote->http_proxy,
453                                          key, value);
454         } else if (!strcmp(subkey, ".vcs")) {
455                 return git_config_string(&remote->foreign_vcs, key, value);
456         }
457         return 0;
458 }
459
460 static void alias_all_urls(void)
461 {
462         int i, j;
463         for (i = 0; i < remotes_nr; i++) {
464                 int add_pushurl_aliases;
465                 if (!remotes[i])
466                         continue;
467                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
468                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
469                 }
470                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
471                 for (j = 0; j < remotes[i]->url_nr; j++) {
472                         if (add_pushurl_aliases)
473                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
474                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
475                 }
476         }
477 }
478
479 static void read_config(void)
480 {
481         unsigned char sha1[20];
482         const char *head_ref;
483         int flag;
484         if (default_remote_name) /* did this already */
485                 return;
486         default_remote_name = "origin";
487         current_branch = NULL;
488         head_ref = resolve_ref_unsafe("HEAD", sha1, 0, &flag);
489         if (head_ref && (flag & REF_ISSYMREF) &&
490             !prefixcmp(head_ref, "refs/heads/")) {
491                 current_branch =
492                         make_branch(head_ref + strlen("refs/heads/"), 0);
493         }
494         git_config(handle_config, NULL);
495         alias_all_urls();
496 }
497
498 /*
499  * This function frees a refspec array.
500  * Warning: code paths should be checked to ensure that the src
501  *          and dst pointers are always freeable pointers as well
502  *          as the refspec pointer itself.
503  */
504 static void free_refspecs(struct refspec *refspec, int nr_refspec)
505 {
506         int i;
507
508         if (!refspec)
509                 return;
510
511         for (i = 0; i < nr_refspec; i++) {
512                 free(refspec[i].src);
513                 free(refspec[i].dst);
514         }
515         free(refspec);
516 }
517
518 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
519 {
520         int i;
521         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
522
523         for (i = 0; i < nr_refspec; i++) {
524                 size_t llen;
525                 int is_glob;
526                 const char *lhs, *rhs;
527                 int flags;
528
529                 is_glob = 0;
530
531                 lhs = refspec[i];
532                 if (*lhs == '+') {
533                         rs[i].force = 1;
534                         lhs++;
535                 }
536
537                 rhs = strrchr(lhs, ':');
538
539                 /*
540                  * Before going on, special case ":" (or "+:") as a refspec
541                  * for pushing matching refs.
542                  */
543                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
544                         rs[i].matching = 1;
545                         continue;
546                 }
547
548                 if (rhs) {
549                         size_t rlen = strlen(++rhs);
550                         is_glob = (1 <= rlen && strchr(rhs, '*'));
551                         rs[i].dst = xstrndup(rhs, rlen);
552                 }
553
554                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
555                 if (1 <= llen && memchr(lhs, '*', llen)) {
556                         if ((rhs && !is_glob) || (!rhs && fetch))
557                                 goto invalid;
558                         is_glob = 1;
559                 } else if (rhs && is_glob) {
560                         goto invalid;
561                 }
562
563                 rs[i].pattern = is_glob;
564                 rs[i].src = xstrndup(lhs, llen);
565                 flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
566
567                 if (fetch) {
568                         unsigned char unused[40];
569
570                         /* LHS */
571                         if (!*rs[i].src)
572                                 ; /* empty is ok; it means "HEAD" */
573                         else if (llen == 40 && !get_sha1_hex(rs[i].src, unused))
574                                 rs[i].exact_sha1 = 1; /* ok */
575                         else if (!check_refname_format(rs[i].src, flags))
576                                 ; /* valid looking ref is ok */
577                         else
578                                 goto invalid;
579                         /* RHS */
580                         if (!rs[i].dst)
581                                 ; /* missing is ok; it is the same as empty */
582                         else if (!*rs[i].dst)
583                                 ; /* empty is ok; it means "do not store" */
584                         else if (!check_refname_format(rs[i].dst, flags))
585                                 ; /* valid looking ref is ok */
586                         else
587                                 goto invalid;
588                 } else {
589                         /*
590                          * LHS
591                          * - empty is allowed; it means delete.
592                          * - when wildcarded, it must be a valid looking ref.
593                          * - otherwise, it must be an extended SHA-1, but
594                          *   there is no existing way to validate this.
595                          */
596                         if (!*rs[i].src)
597                                 ; /* empty is ok */
598                         else if (is_glob) {
599                                 if (check_refname_format(rs[i].src, flags))
600                                         goto invalid;
601                         }
602                         else
603                                 ; /* anything goes, for now */
604                         /*
605                          * RHS
606                          * - missing is allowed, but LHS then must be a
607                          *   valid looking ref.
608                          * - empty is not allowed.
609                          * - otherwise it must be a valid looking ref.
610                          */
611                         if (!rs[i].dst) {
612                                 if (check_refname_format(rs[i].src, flags))
613                                         goto invalid;
614                         } else if (!*rs[i].dst) {
615                                 goto invalid;
616                         } else {
617                                 if (check_refname_format(rs[i].dst, flags))
618                                         goto invalid;
619                         }
620                 }
621         }
622         return rs;
623
624  invalid:
625         if (verify) {
626                 /*
627                  * nr_refspec must be greater than zero and i must be valid
628                  * since it is only possible to reach this point from within
629                  * the for loop above.
630                  */
631                 free_refspecs(rs, i+1);
632                 return NULL;
633         }
634         die("Invalid refspec '%s'", refspec[i]);
635 }
636
637 int valid_fetch_refspec(const char *fetch_refspec_str)
638 {
639         struct refspec *refspec;
640
641         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
642         free_refspecs(refspec, 1);
643         return !!refspec;
644 }
645
646 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
647 {
648         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
649 }
650
651 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
652 {
653         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
654 }
655
656 void free_refspec(int nr_refspec, struct refspec *refspec)
657 {
658         int i;
659         for (i = 0; i < nr_refspec; i++) {
660                 free(refspec[i].src);
661                 free(refspec[i].dst);
662         }
663         free(refspec);
664 }
665
666 static int valid_remote_nick(const char *name)
667 {
668         if (!name[0] || is_dot_or_dotdot(name))
669                 return 0;
670         return !strchr(name, '/'); /* no slash */
671 }
672
673 static struct remote *remote_get_1(const char *name, const char *pushremote_name)
674 {
675         struct remote *ret;
676         int name_given = 0;
677
678         if (name)
679                 name_given = 1;
680         else {
681                 if (pushremote_name) {
682                         name = pushremote_name;
683                         name_given = 1;
684                 } else {
685                         name = default_remote_name;
686                         name_given = explicit_default_remote_name;
687                 }
688         }
689
690         ret = make_remote(name, 0);
691         if (valid_remote_nick(name)) {
692                 if (!valid_remote(ret))
693                         read_remotes_file(ret);
694                 if (!valid_remote(ret))
695                         read_branches_file(ret);
696         }
697         if (name_given && !valid_remote(ret))
698                 add_url_alias(ret, name);
699         if (!valid_remote(ret))
700                 return NULL;
701         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
702         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
703         return ret;
704 }
705
706 struct remote *remote_get(const char *name)
707 {
708         read_config();
709         return remote_get_1(name, NULL);
710 }
711
712 struct remote *pushremote_get(const char *name)
713 {
714         read_config();
715         return remote_get_1(name, pushremote_name);
716 }
717
718 int remote_is_configured(const char *name)
719 {
720         int i;
721         read_config();
722
723         for (i = 0; i < remotes_nr; i++)
724                 if (!strcmp(name, remotes[i]->name))
725                         return 1;
726         return 0;
727 }
728
729 int for_each_remote(each_remote_fn fn, void *priv)
730 {
731         int i, result = 0;
732         read_config();
733         for (i = 0; i < remotes_nr && !result; i++) {
734                 struct remote *r = remotes[i];
735                 if (!r)
736                         continue;
737                 if (!r->fetch)
738                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
739                                                        r->fetch_refspec);
740                 if (!r->push)
741                         r->push = parse_push_refspec(r->push_refspec_nr,
742                                                      r->push_refspec);
743                 result = fn(r, priv);
744         }
745         return result;
746 }
747
748 void ref_remove_duplicates(struct ref *ref_map)
749 {
750         struct string_list refs = STRING_LIST_INIT_NODUP;
751         struct string_list_item *item = NULL;
752         struct ref *prev = NULL, *next = NULL;
753         for (; ref_map; prev = ref_map, ref_map = next) {
754                 next = ref_map->next;
755                 if (!ref_map->peer_ref)
756                         continue;
757
758                 item = string_list_lookup(&refs, ref_map->peer_ref->name);
759                 if (item) {
760                         if (strcmp(((struct ref *)item->util)->name,
761                                    ref_map->name))
762                                 die("%s tracks both %s and %s",
763                                     ref_map->peer_ref->name,
764                                     ((struct ref *)item->util)->name,
765                                     ref_map->name);
766                         prev->next = ref_map->next;
767                         free(ref_map->peer_ref);
768                         free(ref_map);
769                         ref_map = prev; /* skip this; we freed it */
770                         continue;
771                 }
772
773                 item = string_list_insert(&refs, ref_map->peer_ref->name);
774                 item->util = ref_map;
775         }
776         string_list_clear(&refs, 0);
777 }
778
779 int remote_has_url(struct remote *remote, const char *url)
780 {
781         int i;
782         for (i = 0; i < remote->url_nr; i++) {
783                 if (!strcmp(remote->url[i], url))
784                         return 1;
785         }
786         return 0;
787 }
788
789 static int match_name_with_pattern(const char *key, const char *name,
790                                    const char *value, char **result)
791 {
792         const char *kstar = strchr(key, '*');
793         size_t klen;
794         size_t ksuffixlen;
795         size_t namelen;
796         int ret;
797         if (!kstar)
798                 die("Key '%s' of pattern had no '*'", key);
799         klen = kstar - key;
800         ksuffixlen = strlen(kstar + 1);
801         namelen = strlen(name);
802         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
803                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
804         if (ret && value) {
805                 const char *vstar = strchr(value, '*');
806                 size_t vlen;
807                 size_t vsuffixlen;
808                 if (!vstar)
809                         die("Value '%s' of pattern has no '*'", value);
810                 vlen = vstar - value;
811                 vsuffixlen = strlen(vstar + 1);
812                 *result = xmalloc(vlen + vsuffixlen +
813                                   strlen(name) -
814                                   klen - ksuffixlen + 1);
815                 strncpy(*result, value, vlen);
816                 strncpy(*result + vlen,
817                         name + klen, namelen - klen - ksuffixlen);
818                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
819                        vstar + 1);
820         }
821         return ret;
822 }
823
824 static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
825 {
826         int i;
827         int find_src = !query->src;
828
829         if (find_src && !query->dst)
830                 return error("query_refspecs: need either src or dst");
831
832         for (i = 0; i < ref_count; i++) {
833                 struct refspec *refspec = &refs[i];
834                 const char *key = find_src ? refspec->dst : refspec->src;
835                 const char *value = find_src ? refspec->src : refspec->dst;
836                 const char *needle = find_src ? query->dst : query->src;
837                 char **result = find_src ? &query->src : &query->dst;
838
839                 if (!refspec->dst)
840                         continue;
841                 if (refspec->pattern) {
842                         if (match_name_with_pattern(key, needle, value, result)) {
843                                 query->force = refspec->force;
844                                 return 0;
845                         }
846                 } else if (!strcmp(needle, key)) {
847                         *result = xstrdup(value);
848                         query->force = refspec->force;
849                         return 0;
850                 }
851         }
852         return -1;
853 }
854
855 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
856                      const char *name)
857 {
858         struct refspec query;
859
860         memset(&query, 0, sizeof(struct refspec));
861         query.src = (char *)name;
862
863         if (query_refspecs(refspecs, nr_refspec, &query))
864                 return NULL;
865
866         return query.dst;
867 }
868
869 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
870 {
871         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
872 }
873
874 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
875                 const char *name)
876 {
877         size_t len = strlen(name);
878         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
879         memcpy(ref->name, prefix, prefixlen);
880         memcpy(ref->name + prefixlen, name, len);
881         return ref;
882 }
883
884 struct ref *alloc_ref(const char *name)
885 {
886         return alloc_ref_with_prefix("", 0, name);
887 }
888
889 struct ref *copy_ref(const struct ref *ref)
890 {
891         struct ref *cpy;
892         size_t len;
893         if (!ref)
894                 return NULL;
895         len = strlen(ref->name);
896         cpy = xmalloc(sizeof(struct ref) + len + 1);
897         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
898         cpy->next = NULL;
899         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
900         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
901         cpy->peer_ref = copy_ref(ref->peer_ref);
902         return cpy;
903 }
904
905 struct ref *copy_ref_list(const struct ref *ref)
906 {
907         struct ref *ret = NULL;
908         struct ref **tail = &ret;
909         while (ref) {
910                 *tail = copy_ref(ref);
911                 ref = ref->next;
912                 tail = &((*tail)->next);
913         }
914         return ret;
915 }
916
917 static void free_ref(struct ref *ref)
918 {
919         if (!ref)
920                 return;
921         free_ref(ref->peer_ref);
922         free(ref->remote_status);
923         free(ref->symref);
924         free(ref);
925 }
926
927 void free_refs(struct ref *ref)
928 {
929         struct ref *next;
930         while (ref) {
931                 next = ref->next;
932                 free_ref(ref);
933                 ref = next;
934         }
935 }
936
937 int ref_compare_name(const void *va, const void *vb)
938 {
939         const struct ref *a = va, *b = vb;
940         return strcmp(a->name, b->name);
941 }
942
943 static void *ref_list_get_next(const void *a)
944 {
945         return ((const struct ref *)a)->next;
946 }
947
948 static void ref_list_set_next(void *a, void *next)
949 {
950         ((struct ref *)a)->next = next;
951 }
952
953 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
954 {
955         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
956 }
957
958 static int count_refspec_match(const char *pattern,
959                                struct ref *refs,
960                                struct ref **matched_ref)
961 {
962         int patlen = strlen(pattern);
963         struct ref *matched_weak = NULL;
964         struct ref *matched = NULL;
965         int weak_match = 0;
966         int match = 0;
967
968         for (weak_match = match = 0; refs; refs = refs->next) {
969                 char *name = refs->name;
970                 int namelen = strlen(name);
971
972                 if (!refname_match(pattern, name, ref_rev_parse_rules))
973                         continue;
974
975                 /* A match is "weak" if it is with refs outside
976                  * heads or tags, and did not specify the pattern
977                  * in full (e.g. "refs/remotes/origin/master") or at
978                  * least from the toplevel (e.g. "remotes/origin/master");
979                  * otherwise "git push $URL master" would result in
980                  * ambiguity between remotes/origin/master and heads/master
981                  * at the remote site.
982                  */
983                 if (namelen != patlen &&
984                     patlen != namelen - 5 &&
985                     prefixcmp(name, "refs/heads/") &&
986                     prefixcmp(name, "refs/tags/")) {
987                         /* We want to catch the case where only weak
988                          * matches are found and there are multiple
989                          * matches, and where more than one strong
990                          * matches are found, as ambiguous.  One
991                          * strong match with zero or more weak matches
992                          * are acceptable as a unique match.
993                          */
994                         matched_weak = refs;
995                         weak_match++;
996                 }
997                 else {
998                         matched = refs;
999                         match++;
1000                 }
1001         }
1002         if (!matched) {
1003                 *matched_ref = matched_weak;
1004                 return weak_match;
1005         }
1006         else {
1007                 *matched_ref = matched;
1008                 return match;
1009         }
1010 }
1011
1012 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1013 {
1014         **tail = ref;
1015         while (ref->next)
1016                 ref = ref->next;
1017         *tail = &ref->next;
1018 }
1019
1020 static struct ref *alloc_delete_ref(void)
1021 {
1022         struct ref *ref = alloc_ref("(delete)");
1023         hashclr(ref->new_sha1);
1024         return ref;
1025 }
1026
1027 static struct ref *try_explicit_object_name(const char *name)
1028 {
1029         unsigned char sha1[20];
1030         struct ref *ref;
1031
1032         if (!*name)
1033                 return alloc_delete_ref();
1034         if (get_sha1(name, sha1))
1035                 return NULL;
1036         ref = alloc_ref(name);
1037         hashcpy(ref->new_sha1, sha1);
1038         return ref;
1039 }
1040
1041 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1042 {
1043         struct ref *ret = alloc_ref(name);
1044         tail_link_ref(ret, tail);
1045         return ret;
1046 }
1047
1048 static char *guess_ref(const char *name, struct ref *peer)
1049 {
1050         struct strbuf buf = STRBUF_INIT;
1051         unsigned char sha1[20];
1052
1053         const char *r = resolve_ref_unsafe(peer->name, sha1, 1, NULL);
1054         if (!r)
1055                 return NULL;
1056
1057         if (!prefixcmp(r, "refs/heads/"))
1058                 strbuf_addstr(&buf, "refs/heads/");
1059         else if (!prefixcmp(r, "refs/tags/"))
1060                 strbuf_addstr(&buf, "refs/tags/");
1061         else
1062                 return NULL;
1063
1064         strbuf_addstr(&buf, name);
1065         return strbuf_detach(&buf, NULL);
1066 }
1067
1068 static int match_explicit(struct ref *src, struct ref *dst,
1069                           struct ref ***dst_tail,
1070                           struct refspec *rs)
1071 {
1072         struct ref *matched_src, *matched_dst;
1073         int copy_src;
1074
1075         const char *dst_value = rs->dst;
1076         char *dst_guess;
1077
1078         if (rs->pattern || rs->matching)
1079                 return 0;
1080
1081         matched_src = matched_dst = NULL;
1082         switch (count_refspec_match(rs->src, src, &matched_src)) {
1083         case 1:
1084                 copy_src = 1;
1085                 break;
1086         case 0:
1087                 /* The source could be in the get_sha1() format
1088                  * not a reference name.  :refs/other is a
1089                  * way to delete 'other' ref at the remote end.
1090                  */
1091                 matched_src = try_explicit_object_name(rs->src);
1092                 if (!matched_src)
1093                         return error("src refspec %s does not match any.", rs->src);
1094                 copy_src = 0;
1095                 break;
1096         default:
1097                 return error("src refspec %s matches more than one.", rs->src);
1098         }
1099
1100         if (!dst_value) {
1101                 unsigned char sha1[20];
1102                 int flag;
1103
1104                 dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
1105                 if (!dst_value ||
1106                     ((flag & REF_ISSYMREF) &&
1107                      prefixcmp(dst_value, "refs/heads/")))
1108                         die("%s cannot be resolved to branch.",
1109                             matched_src->name);
1110         }
1111
1112         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1113         case 1:
1114                 break;
1115         case 0:
1116                 if (!memcmp(dst_value, "refs/", 5))
1117                         matched_dst = make_linked_ref(dst_value, dst_tail);
1118                 else if (is_null_sha1(matched_src->new_sha1))
1119                         error("unable to delete '%s': remote ref does not exist",
1120                               dst_value);
1121                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1122                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1123                 else
1124                         error("unable to push to unqualified destination: %s\n"
1125                               "The destination refspec neither matches an "
1126                               "existing ref on the remote nor\n"
1127                               "begins with refs/, and we are unable to "
1128                               "guess a prefix based on the source ref.",
1129                               dst_value);
1130                 break;
1131         default:
1132                 matched_dst = NULL;
1133                 error("dst refspec %s matches more than one.",
1134                       dst_value);
1135                 break;
1136         }
1137         if (!matched_dst)
1138                 return -1;
1139         if (matched_dst->peer_ref)
1140                 return error("dst ref %s receives from more than one src.",
1141                       matched_dst->name);
1142         else {
1143                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1144                 matched_dst->force = rs->force;
1145         }
1146         return 0;
1147 }
1148
1149 static int match_explicit_refs(struct ref *src, struct ref *dst,
1150                                struct ref ***dst_tail, struct refspec *rs,
1151                                int rs_nr)
1152 {
1153         int i, errs;
1154         for (i = errs = 0; i < rs_nr; i++)
1155                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1156         return errs;
1157 }
1158
1159 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1160                 int send_mirror, int direction, const struct refspec **ret_pat)
1161 {
1162         const struct refspec *pat;
1163         char *name;
1164         int i;
1165         int matching_refs = -1;
1166         for (i = 0; i < rs_nr; i++) {
1167                 if (rs[i].matching &&
1168                     (matching_refs == -1 || rs[i].force)) {
1169                         matching_refs = i;
1170                         continue;
1171                 }
1172
1173                 if (rs[i].pattern) {
1174                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1175                         int match;
1176                         if (direction == FROM_SRC)
1177                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1178                         else
1179                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1180                         if (match) {
1181                                 matching_refs = i;
1182                                 break;
1183                         }
1184                 }
1185         }
1186         if (matching_refs == -1)
1187                 return NULL;
1188
1189         pat = rs + matching_refs;
1190         if (pat->matching) {
1191                 /*
1192                  * "matching refs"; traditionally we pushed everything
1193                  * including refs outside refs/heads/ hierarchy, but
1194                  * that does not make much sense these days.
1195                  */
1196                 if (!send_mirror && prefixcmp(ref->name, "refs/heads/"))
1197                         return NULL;
1198                 name = xstrdup(ref->name);
1199         }
1200         if (ret_pat)
1201                 *ret_pat = pat;
1202         return name;
1203 }
1204
1205 static struct ref **tail_ref(struct ref **head)
1206 {
1207         struct ref **tail = head;
1208         while (*tail)
1209                 tail = &((*tail)->next);
1210         return tail;
1211 }
1212
1213 struct tips {
1214         struct commit **tip;
1215         int nr, alloc;
1216 };
1217
1218 static void add_to_tips(struct tips *tips, const unsigned char *sha1)
1219 {
1220         struct commit *commit;
1221
1222         if (is_null_sha1(sha1))
1223                 return;
1224         commit = lookup_commit_reference_gently(sha1, 1);
1225         if (!commit || (commit->object.flags & TMP_MARK))
1226                 return;
1227         commit->object.flags |= TMP_MARK;
1228         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1229         tips->tip[tips->nr++] = commit;
1230 }
1231
1232 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1233 {
1234         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1235         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1236         struct string_list_item *item;
1237         struct ref *ref;
1238         struct tips sent_tips;
1239
1240         /*
1241          * Collect everything we know they would have at the end of
1242          * this push, and collect all tags they have.
1243          */
1244         memset(&sent_tips, 0, sizeof(sent_tips));
1245         for (ref = *dst; ref; ref = ref->next) {
1246                 if (ref->peer_ref &&
1247                     !is_null_sha1(ref->peer_ref->new_sha1))
1248                         add_to_tips(&sent_tips, ref->peer_ref->new_sha1);
1249                 else
1250                         add_to_tips(&sent_tips, ref->old_sha1);
1251                 if (!prefixcmp(ref->name, "refs/tags/"))
1252                         string_list_append(&dst_tag, ref->name);
1253         }
1254         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1255
1256         sort_string_list(&dst_tag);
1257
1258         /* Collect tags they do not have. */
1259         for (ref = src; ref; ref = ref->next) {
1260                 if (prefixcmp(ref->name, "refs/tags/"))
1261                         continue; /* not a tag */
1262                 if (string_list_has_string(&dst_tag, ref->name))
1263                         continue; /* they already have it */
1264                 if (sha1_object_info(ref->new_sha1, NULL) != OBJ_TAG)
1265                         continue; /* be conservative */
1266                 item = string_list_append(&src_tag, ref->name);
1267                 item->util = ref;
1268         }
1269         string_list_clear(&dst_tag, 0);
1270
1271         /*
1272          * At this point, src_tag lists tags that are missing from
1273          * dst, and sent_tips lists the tips we are pushing or those
1274          * that we know they already have. An element in the src_tag
1275          * that is an ancestor of any of the sent_tips needs to be
1276          * sent to the other side.
1277          */
1278         if (sent_tips.nr) {
1279                 for_each_string_list_item(item, &src_tag) {
1280                         struct ref *ref = item->util;
1281                         struct ref *dst_ref;
1282                         struct commit *commit;
1283
1284                         if (is_null_sha1(ref->new_sha1))
1285                                 continue;
1286                         commit = lookup_commit_reference_gently(ref->new_sha1, 1);
1287                         if (!commit)
1288                                 /* not pushing a commit, which is not an error */
1289                                 continue;
1290
1291                         /*
1292                          * Is this tag, which they do not have, reachable from
1293                          * any of the commits we are sending?
1294                          */
1295                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1296                                 continue;
1297
1298                         /* Add it in */
1299                         dst_ref = make_linked_ref(ref->name, dst_tail);
1300                         hashcpy(dst_ref->new_sha1, ref->new_sha1);
1301                         dst_ref->peer_ref = copy_ref(ref);
1302                 }
1303         }
1304         string_list_clear(&src_tag, 0);
1305         free(sent_tips.tip);
1306 }
1307
1308 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1309 {
1310         for ( ; list; list = list->next)
1311                 if (!strcmp(list->name, name))
1312                         return (struct ref *)list;
1313         return NULL;
1314 }
1315
1316 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1317 {
1318         for ( ; ref; ref = ref->next)
1319                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1320
1321         sort_string_list(ref_index);
1322 }
1323
1324 /*
1325  * Given the set of refs the local repository has, the set of refs the
1326  * remote repository has, and the refspec used for push, determine
1327  * what remote refs we will update and with what value by setting
1328  * peer_ref (which object is being pushed) and force (if the push is
1329  * forced) in elements of "dst". The function may add new elements to
1330  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1331  */
1332 int match_push_refs(struct ref *src, struct ref **dst,
1333                     int nr_refspec, const char **refspec, int flags)
1334 {
1335         struct refspec *rs;
1336         int send_all = flags & MATCH_REFS_ALL;
1337         int send_mirror = flags & MATCH_REFS_MIRROR;
1338         int send_prune = flags & MATCH_REFS_PRUNE;
1339         int errs;
1340         static const char *default_refspec[] = { ":", NULL };
1341         struct ref *ref, **dst_tail = tail_ref(dst);
1342         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1343
1344         if (!nr_refspec) {
1345                 nr_refspec = 1;
1346                 refspec = default_refspec;
1347         }
1348         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1349         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1350
1351         /* pick the remainder */
1352         for (ref = src; ref; ref = ref->next) {
1353                 struct string_list_item *dst_item;
1354                 struct ref *dst_peer;
1355                 const struct refspec *pat = NULL;
1356                 char *dst_name;
1357
1358                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1359                 if (!dst_name)
1360                         continue;
1361
1362                 if (!dst_ref_index.nr)
1363                         prepare_ref_index(&dst_ref_index, *dst);
1364
1365                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1366                 dst_peer = dst_item ? dst_item->util : NULL;
1367                 if (dst_peer) {
1368                         if (dst_peer->peer_ref)
1369                                 /* We're already sending something to this ref. */
1370                                 goto free_name;
1371                 } else {
1372                         if (pat->matching && !(send_all || send_mirror))
1373                                 /*
1374                                  * Remote doesn't have it, and we have no
1375                                  * explicit pattern, and we don't have
1376                                  * --all nor --mirror.
1377                                  */
1378                                 goto free_name;
1379
1380                         /* Create a new one and link it */
1381                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1382                         hashcpy(dst_peer->new_sha1, ref->new_sha1);
1383                         string_list_insert(&dst_ref_index,
1384                                 dst_peer->name)->util = dst_peer;
1385                 }
1386                 dst_peer->peer_ref = copy_ref(ref);
1387                 dst_peer->force = pat->force;
1388         free_name:
1389                 free(dst_name);
1390         }
1391
1392         string_list_clear(&dst_ref_index, 0);
1393
1394         if (flags & MATCH_REFS_FOLLOW_TAGS)
1395                 add_missing_tags(src, dst, &dst_tail);
1396
1397         if (send_prune) {
1398                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1399                 /* check for missing refs on the remote */
1400                 for (ref = *dst; ref; ref = ref->next) {
1401                         char *src_name;
1402
1403                         if (ref->peer_ref)
1404                                 /* We're already sending something to this ref. */
1405                                 continue;
1406
1407                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1408                         if (src_name) {
1409                                 if (!src_ref_index.nr)
1410                                         prepare_ref_index(&src_ref_index, src);
1411                                 if (!string_list_has_string(&src_ref_index,
1412                                             src_name))
1413                                         ref->peer_ref = alloc_delete_ref();
1414                                 free(src_name);
1415                         }
1416                 }
1417                 string_list_clear(&src_ref_index, 0);
1418         }
1419         if (errs)
1420                 return -1;
1421         return 0;
1422 }
1423
1424 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1425                              int force_update)
1426 {
1427         struct ref *ref;
1428
1429         for (ref = remote_refs; ref; ref = ref->next) {
1430                 int force_ref_update = ref->force || force_update;
1431                 int reject_reason = 0;
1432
1433                 if (ref->peer_ref)
1434                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1435                 else if (!send_mirror)
1436                         continue;
1437
1438                 ref->deletion = is_null_sha1(ref->new_sha1);
1439                 if (!ref->deletion &&
1440                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1441                         ref->status = REF_STATUS_UPTODATE;
1442                         continue;
1443                 }
1444
1445                 /*
1446                  * Bypass the usual "must fast-forward" check but
1447                  * replace it with a weaker "the old value must be
1448                  * this value we observed".  If the remote ref has
1449                  * moved and is now different from what we expect,
1450                  * reject any push.
1451                  *
1452                  * It also is an error if the user told us to check
1453                  * with the remote-tracking branch to find the value
1454                  * to expect, but we did not have such a tracking
1455                  * branch.
1456                  */
1457                 if (ref->expect_old_sha1) {
1458                         if (ref->expect_old_no_trackback ||
1459                             hashcmp(ref->old_sha1, ref->old_sha1_expect))
1460                                 reject_reason = REF_STATUS_REJECT_STALE;
1461                 }
1462
1463                 /*
1464                  * The usual "must fast-forward" rules.
1465                  *
1466                  * Decide whether an individual refspec A:B can be
1467                  * pushed.  The push will succeed if any of the
1468                  * following are true:
1469                  *
1470                  * (1) the remote reference B does not exist
1471                  *
1472                  * (2) the remote reference B is being removed (i.e.,
1473                  *     pushing :B where no source is specified)
1474                  *
1475                  * (3) the destination is not under refs/tags/, and
1476                  *     if the old and new value is a commit, the new
1477                  *     is a descendant of the old.
1478                  *
1479                  * (4) it is forced using the +A:B notation, or by
1480                  *     passing the --force argument
1481                  */
1482
1483                 else if (!ref->deletion && !is_null_sha1(ref->old_sha1)) {
1484                         if (!prefixcmp(ref->name, "refs/tags/"))
1485                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1486                         else if (!has_sha1_file(ref->old_sha1))
1487                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1488                         else if (!lookup_commit_reference_gently(ref->old_sha1, 1) ||
1489                                  !lookup_commit_reference_gently(ref->new_sha1, 1))
1490                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1491                         else if (!ref_newer(ref->new_sha1, ref->old_sha1))
1492                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1493                 }
1494
1495                 /*
1496                  * "--force" will defeat any rejection implemented
1497                  * by the rules above.
1498                  */
1499                 if (!force_ref_update)
1500                         ref->status = reject_reason;
1501                 else if (reject_reason)
1502                         ref->forced_update = 1;
1503         }
1504 }
1505
1506 struct branch *branch_get(const char *name)
1507 {
1508         struct branch *ret;
1509
1510         read_config();
1511         if (!name || !*name || !strcmp(name, "HEAD"))
1512                 ret = current_branch;
1513         else
1514                 ret = make_branch(name, 0);
1515         if (ret && ret->remote_name) {
1516                 ret->remote = remote_get(ret->remote_name);
1517                 if (ret->merge_nr) {
1518                         int i;
1519                         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1520                         for (i = 0; i < ret->merge_nr; i++) {
1521                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1522                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1523                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1524                                     && !strcmp(ret->remote_name, "."))
1525                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1526                         }
1527                 }
1528         }
1529         return ret;
1530 }
1531
1532 int branch_has_merge_config(struct branch *branch)
1533 {
1534         return branch && !!branch->merge;
1535 }
1536
1537 int branch_merge_matches(struct branch *branch,
1538                                  int i,
1539                                  const char *refname)
1540 {
1541         if (!branch || i < 0 || i >= branch->merge_nr)
1542                 return 0;
1543         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1544 }
1545
1546 static int ignore_symref_update(const char *refname)
1547 {
1548         unsigned char sha1[20];
1549         int flag;
1550
1551         if (!resolve_ref_unsafe(refname, sha1, 0, &flag))
1552                 return 0; /* non-existing refs are OK */
1553         return (flag & REF_ISSYMREF);
1554 }
1555
1556 static struct ref *get_expanded_map(const struct ref *remote_refs,
1557                                     const struct refspec *refspec)
1558 {
1559         const struct ref *ref;
1560         struct ref *ret = NULL;
1561         struct ref **tail = &ret;
1562
1563         char *expn_name;
1564
1565         for (ref = remote_refs; ref; ref = ref->next) {
1566                 if (strchr(ref->name, '^'))
1567                         continue; /* a dereference item */
1568                 if (match_name_with_pattern(refspec->src, ref->name,
1569                                             refspec->dst, &expn_name) &&
1570                     !ignore_symref_update(expn_name)) {
1571                         struct ref *cpy = copy_ref(ref);
1572
1573                         cpy->peer_ref = alloc_ref(expn_name);
1574                         free(expn_name);
1575                         if (refspec->force)
1576                                 cpy->peer_ref->force = 1;
1577                         *tail = cpy;
1578                         tail = &cpy->next;
1579                 }
1580         }
1581
1582         return ret;
1583 }
1584
1585 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1586 {
1587         const struct ref *ref;
1588         for (ref = refs; ref; ref = ref->next) {
1589                 if (refname_match(name, ref->name, ref_fetch_rules))
1590                         return ref;
1591         }
1592         return NULL;
1593 }
1594
1595 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1596 {
1597         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1598
1599         if (!ref)
1600                 return NULL;
1601
1602         return copy_ref(ref);
1603 }
1604
1605 static struct ref *get_local_ref(const char *name)
1606 {
1607         if (!name || name[0] == '\0')
1608                 return NULL;
1609
1610         if (!prefixcmp(name, "refs/"))
1611                 return alloc_ref(name);
1612
1613         if (!prefixcmp(name, "heads/") ||
1614             !prefixcmp(name, "tags/") ||
1615             !prefixcmp(name, "remotes/"))
1616                 return alloc_ref_with_prefix("refs/", 5, name);
1617
1618         return alloc_ref_with_prefix("refs/heads/", 11, name);
1619 }
1620
1621 int get_fetch_map(const struct ref *remote_refs,
1622                   const struct refspec *refspec,
1623                   struct ref ***tail,
1624                   int missing_ok)
1625 {
1626         struct ref *ref_map, **rmp;
1627
1628         if (refspec->pattern) {
1629                 ref_map = get_expanded_map(remote_refs, refspec);
1630         } else {
1631                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1632
1633                 if (refspec->exact_sha1) {
1634                         ref_map = alloc_ref(name);
1635                         get_sha1_hex(name, ref_map->old_sha1);
1636                 } else {
1637                         ref_map = get_remote_ref(remote_refs, name);
1638                 }
1639                 if (!missing_ok && !ref_map)
1640                         die("Couldn't find remote ref %s", name);
1641                 if (ref_map) {
1642                         ref_map->peer_ref = get_local_ref(refspec->dst);
1643                         if (ref_map->peer_ref && refspec->force)
1644                                 ref_map->peer_ref->force = 1;
1645                 }
1646         }
1647
1648         for (rmp = &ref_map; *rmp; ) {
1649                 if ((*rmp)->peer_ref) {
1650                         if (prefixcmp((*rmp)->peer_ref->name, "refs/") ||
1651                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1652                                 struct ref *ignore = *rmp;
1653                                 error("* Ignoring funny ref '%s' locally",
1654                                       (*rmp)->peer_ref->name);
1655                                 *rmp = (*rmp)->next;
1656                                 free(ignore->peer_ref);
1657                                 free(ignore);
1658                                 continue;
1659                         }
1660                 }
1661                 rmp = &((*rmp)->next);
1662         }
1663
1664         if (ref_map)
1665                 tail_link_ref(ref_map, tail);
1666
1667         return 0;
1668 }
1669
1670 int resolve_remote_symref(struct ref *ref, struct ref *list)
1671 {
1672         if (!ref->symref)
1673                 return 0;
1674         for (; list; list = list->next)
1675                 if (!strcmp(ref->symref, list->name)) {
1676                         hashcpy(ref->old_sha1, list->old_sha1);
1677                         return 0;
1678                 }
1679         return 1;
1680 }
1681
1682 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1683 {
1684         while (list) {
1685                 struct commit_list *temp = list;
1686                 temp->item->object.flags &= ~mark;
1687                 list = temp->next;
1688                 free(temp);
1689         }
1690 }
1691
1692 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1693 {
1694         struct object *o;
1695         struct commit *old, *new;
1696         struct commit_list *list, *used;
1697         int found = 0;
1698
1699         /*
1700          * Both new and old must be commit-ish and new is descendant of
1701          * old.  Otherwise we require --force.
1702          */
1703         o = deref_tag(parse_object(old_sha1), NULL, 0);
1704         if (!o || o->type != OBJ_COMMIT)
1705                 return 0;
1706         old = (struct commit *) o;
1707
1708         o = deref_tag(parse_object(new_sha1), NULL, 0);
1709         if (!o || o->type != OBJ_COMMIT)
1710                 return 0;
1711         new = (struct commit *) o;
1712
1713         if (parse_commit(new) < 0)
1714                 return 0;
1715
1716         used = list = NULL;
1717         commit_list_insert(new, &list);
1718         while (list) {
1719                 new = pop_most_recent_commit(&list, TMP_MARK);
1720                 commit_list_insert(new, &used);
1721                 if (new == old) {
1722                         found = 1;
1723                         break;
1724                 }
1725         }
1726         unmark_and_free(list, TMP_MARK);
1727         unmark_and_free(used, TMP_MARK);
1728         return found;
1729 }
1730
1731 /*
1732  * Compare a branch with its upstream, and save their differences (number
1733  * of commits) in *num_ours and *num_theirs.
1734  *
1735  * Return 0 if branch has no upstream (no base), -1 if upstream is missing
1736  * (with "gone" base), otherwise 1 (with base).
1737  */
1738 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1739 {
1740         unsigned char sha1[20];
1741         struct commit *ours, *theirs;
1742         char symmetric[84];
1743         struct rev_info revs;
1744         const char *rev_argv[10], *base;
1745         int rev_argc;
1746
1747         /* Cannot stat unless we are marked to build on top of somebody else. */
1748         if (!branch ||
1749             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1750                 return 0;
1751
1752         /* Cannot stat if what we used to build on no longer exists */
1753         base = branch->merge[0]->dst;
1754         if (read_ref(base, sha1))
1755                 return -1;
1756         theirs = lookup_commit_reference(sha1);
1757         if (!theirs)
1758                 return -1;
1759
1760         if (read_ref(branch->refname, sha1))
1761                 return -1;
1762         ours = lookup_commit_reference(sha1);
1763         if (!ours)
1764                 return -1;
1765
1766         /* are we the same? */
1767         if (theirs == ours) {
1768                 *num_theirs = *num_ours = 0;
1769                 return 1;
1770         }
1771
1772         /* Run "rev-list --left-right ours...theirs" internally... */
1773         rev_argc = 0;
1774         rev_argv[rev_argc++] = NULL;
1775         rev_argv[rev_argc++] = "--left-right";
1776         rev_argv[rev_argc++] = symmetric;
1777         rev_argv[rev_argc++] = "--";
1778         rev_argv[rev_argc] = NULL;
1779
1780         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1781         strcpy(symmetric + 40, "...");
1782         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1783
1784         init_revisions(&revs, NULL);
1785         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1786         prepare_revision_walk(&revs);
1787
1788         /* ... and count the commits on each side. */
1789         *num_ours = 0;
1790         *num_theirs = 0;
1791         while (1) {
1792                 struct commit *c = get_revision(&revs);
1793                 if (!c)
1794                         break;
1795                 if (c->object.flags & SYMMETRIC_LEFT)
1796                         (*num_ours)++;
1797                 else
1798                         (*num_theirs)++;
1799         }
1800
1801         /* clear object flags smudged by the above traversal */
1802         clear_commit_marks(ours, ALL_REV_FLAGS);
1803         clear_commit_marks(theirs, ALL_REV_FLAGS);
1804         return 1;
1805 }
1806
1807 /*
1808  * Return true when there is anything to report, otherwise false.
1809  */
1810 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1811 {
1812         int ours, theirs;
1813         const char *base;
1814         int upstream_is_gone = 0;
1815
1816         switch (stat_tracking_info(branch, &ours, &theirs)) {
1817         case 0:
1818                 /* no base */
1819                 return 0;
1820         case -1:
1821                 /* with "gone" base */
1822                 upstream_is_gone = 1;
1823                 break;
1824         default:
1825                 /* with base */
1826                 break;
1827         }
1828
1829         base = branch->merge[0]->dst;
1830         base = shorten_unambiguous_ref(base, 0);
1831         if (upstream_is_gone) {
1832                 strbuf_addf(sb,
1833                         _("Your branch is based on '%s', but the upstream is gone.\n"),
1834                         base);
1835                 if (advice_status_hints)
1836                         strbuf_addf(sb,
1837                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
1838         } else if (!ours && !theirs) {
1839                 strbuf_addf(sb,
1840                         _("Your branch is up-to-date with '%s'.\n"),
1841                         base);
1842         } else if (!theirs) {
1843                 strbuf_addf(sb,
1844                         Q_("Your branch is ahead of '%s' by %d commit.\n",
1845                            "Your branch is ahead of '%s' by %d commits.\n",
1846                            ours),
1847                         base, ours);
1848                 if (advice_status_hints)
1849                         strbuf_addf(sb,
1850                                 _("  (use \"git push\" to publish your local commits)\n"));
1851         } else if (!ours) {
1852                 strbuf_addf(sb,
1853                         Q_("Your branch is behind '%s' by %d commit, "
1854                                "and can be fast-forwarded.\n",
1855                            "Your branch is behind '%s' by %d commits, "
1856                                "and can be fast-forwarded.\n",
1857                            theirs),
1858                         base, theirs);
1859                 if (advice_status_hints)
1860                         strbuf_addf(sb,
1861                                 _("  (use \"git pull\" to update your local branch)\n"));
1862         } else {
1863                 strbuf_addf(sb,
1864                         Q_("Your branch and '%s' have diverged,\n"
1865                                "and have %d and %d different commit each, "
1866                                "respectively.\n",
1867                            "Your branch and '%s' have diverged,\n"
1868                                "and have %d and %d different commits each, "
1869                                "respectively.\n",
1870                            theirs),
1871                         base, ours, theirs);
1872                 if (advice_status_hints)
1873                         strbuf_addf(sb,
1874                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
1875         }
1876         return 1;
1877 }
1878
1879 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1880 {
1881         struct ref ***local_tail = cb_data;
1882         struct ref *ref;
1883         int len;
1884
1885         /* we already know it starts with refs/ to get here */
1886         if (check_refname_format(refname + 5, 0))
1887                 return 0;
1888
1889         len = strlen(refname) + 1;
1890         ref = xcalloc(1, sizeof(*ref) + len);
1891         hashcpy(ref->new_sha1, sha1);
1892         memcpy(ref->name, refname, len);
1893         **local_tail = ref;
1894         *local_tail = &ref->next;
1895         return 0;
1896 }
1897
1898 struct ref *get_local_heads(void)
1899 {
1900         struct ref *local_refs = NULL, **local_tail = &local_refs;
1901         for_each_ref(one_local_ref, &local_tail);
1902         return local_refs;
1903 }
1904
1905 struct ref *guess_remote_head(const struct ref *head,
1906                               const struct ref *refs,
1907                               int all)
1908 {
1909         const struct ref *r;
1910         struct ref *list = NULL;
1911         struct ref **tail = &list;
1912
1913         if (!head)
1914                 return NULL;
1915
1916         /*
1917          * Some transports support directly peeking at
1918          * where HEAD points; if that is the case, then
1919          * we don't have to guess.
1920          */
1921         if (head->symref)
1922                 return copy_ref(find_ref_by_name(refs, head->symref));
1923
1924         /* If refs/heads/master could be right, it is. */
1925         if (!all) {
1926                 r = find_ref_by_name(refs, "refs/heads/master");
1927                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1928                         return copy_ref(r);
1929         }
1930
1931         /* Look for another ref that points there */
1932         for (r = refs; r; r = r->next) {
1933                 if (r != head &&
1934                     !prefixcmp(r->name, "refs/heads/") &&
1935                     !hashcmp(r->old_sha1, head->old_sha1)) {
1936                         *tail = copy_ref(r);
1937                         tail = &((*tail)->next);
1938                         if (!all)
1939                                 break;
1940                 }
1941         }
1942
1943         return list;
1944 }
1945
1946 struct stale_heads_info {
1947         struct string_list *ref_names;
1948         struct ref **stale_refs_tail;
1949         struct refspec *refs;
1950         int ref_count;
1951 };
1952
1953 static int get_stale_heads_cb(const char *refname,
1954         const unsigned char *sha1, int flags, void *cb_data)
1955 {
1956         struct stale_heads_info *info = cb_data;
1957         struct refspec query;
1958         memset(&query, 0, sizeof(struct refspec));
1959         query.dst = (char *)refname;
1960
1961         if (query_refspecs(info->refs, info->ref_count, &query))
1962                 return 0; /* No matches */
1963
1964         /*
1965          * If we did find a suitable refspec and it's not a symref and
1966          * it's not in the list of refs that currently exist in that
1967          * remote we consider it to be stale.
1968          */
1969         if (!((flags & REF_ISSYMREF) ||
1970               string_list_has_string(info->ref_names, query.src))) {
1971                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
1972                 hashcpy(ref->new_sha1, sha1);
1973         }
1974
1975         free(query.src);
1976         return 0;
1977 }
1978
1979 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
1980 {
1981         struct ref *ref, *stale_refs = NULL;
1982         struct string_list ref_names = STRING_LIST_INIT_NODUP;
1983         struct stale_heads_info info;
1984         info.ref_names = &ref_names;
1985         info.stale_refs_tail = &stale_refs;
1986         info.refs = refs;
1987         info.ref_count = ref_count;
1988         for (ref = fetch_map; ref; ref = ref->next)
1989                 string_list_append(&ref_names, ref->name);
1990         sort_string_list(&ref_names);
1991         for_each_ref(get_stale_heads_cb, &info);
1992         string_list_clear(&ref_names, 0);
1993         return stale_refs;
1994 }
1995
1996 /*
1997  * Compare-and-swap
1998  */
1999 void clear_cas_option(struct push_cas_option *cas)
2000 {
2001         int i;
2002
2003         for (i = 0; i < cas->nr; i++)
2004                 free(cas->entry[i].refname);
2005         free(cas->entry);
2006         memset(cas, 0, sizeof(*cas));
2007 }
2008
2009 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2010                                       const char *refname,
2011                                       size_t refnamelen)
2012 {
2013         struct push_cas *entry;
2014         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2015         entry = &cas->entry[cas->nr++];
2016         memset(entry, 0, sizeof(*entry));
2017         entry->refname = xmemdupz(refname, refnamelen);
2018         return entry;
2019 }
2020
2021 int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2022 {
2023         const char *colon;
2024         struct push_cas *entry;
2025
2026         if (unset) {
2027                 /* "--no-<option>" */
2028                 clear_cas_option(cas);
2029                 return 0;
2030         }
2031
2032         if (!arg) {
2033                 /* just "--<option>" */
2034                 cas->use_tracking_for_rest = 1;
2035                 return 0;
2036         }
2037
2038         /* "--<option>=refname" or "--<option>=refname:value" */
2039         colon = strchrnul(arg, ':');
2040         entry = add_cas_entry(cas, arg, colon - arg);
2041         if (!*colon)
2042                 entry->use_tracking = 1;
2043         else if (get_sha1(colon + 1, entry->expect))
2044                 return error("cannot parse expected object name '%s'", colon + 1);
2045         return 0;
2046 }
2047
2048 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2049 {
2050         return parse_push_cas_option(opt->value, arg, unset);
2051 }
2052
2053 int is_empty_cas(const struct push_cas_option *cas)
2054 {
2055         return !cas->use_tracking_for_rest && !cas->nr;
2056 }
2057
2058 /*
2059  * Look at remote.fetch refspec and see if we have a remote
2060  * tracking branch for the refname there.  Fill its current
2061  * value in sha1[].
2062  * If we cannot do so, return negative to signal an error.
2063  */
2064 static int remote_tracking(struct remote *remote, const char *refname,
2065                            unsigned char sha1[20])
2066 {
2067         char *dst;
2068
2069         dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
2070         if (!dst)
2071                 return -1; /* no tracking ref for refname at remote */
2072         if (read_ref(dst, sha1))
2073                 return -1; /* we know what the tracking ref is but we cannot read it */
2074         return 0;
2075 }
2076
2077 static void apply_cas(struct push_cas_option *cas,
2078                       struct remote *remote,
2079                       struct ref *ref)
2080 {
2081         int i;
2082
2083         /* Find an explicit --<option>=<name>[:<value>] entry */
2084         for (i = 0; i < cas->nr; i++) {
2085                 struct push_cas *entry = &cas->entry[i];
2086                 if (!refname_match(entry->refname, ref->name, ref_rev_parse_rules))
2087                         continue;
2088                 ref->expect_old_sha1 = 1;
2089                 if (!entry->use_tracking)
2090                         hashcpy(ref->old_sha1_expect, cas->entry[i].expect);
2091                 else if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2092                         ref->expect_old_no_trackback = 1;
2093                 return;
2094         }
2095
2096         /* Are we using "--<option>" to cover all? */
2097         if (!cas->use_tracking_for_rest)
2098                 return;
2099
2100         ref->expect_old_sha1 = 1;
2101         if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2102                 ref->expect_old_no_trackback = 1;
2103 }
2104
2105 void apply_push_cas(struct push_cas_option *cas,
2106                     struct remote *remote,
2107                     struct ref *remote_refs)
2108 {
2109         struct ref *ref;
2110         for (ref = remote_refs; ref; ref = ref->next)
2111                 apply_cas(cas, remote, ref);
2112 }