Merge branch 'sp/pack-protocol-doc-on-shallow'
[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 static struct hashmap remotes_hash;
46
47 static struct branch **branches;
48 static int branches_alloc;
49 static int branches_nr;
50
51 static struct branch *current_branch;
52 static const char *default_remote_name;
53 static const char *branch_pushremote_name;
54 static const char *pushremote_name;
55 static int explicit_default_remote_name;
56
57 static struct rewrites rewrites;
58 static struct rewrites rewrites_push;
59
60 #define BUF_SIZE (2048)
61 static char buffer[BUF_SIZE];
62
63 static int valid_remote(const struct remote *remote)
64 {
65         return (!!remote->url) || (!!remote->foreign_vcs);
66 }
67
68 static const char *alias_url(const char *url, struct rewrites *r)
69 {
70         int i, j;
71         char *ret;
72         struct counted_string *longest;
73         int longest_i;
74
75         longest = NULL;
76         longest_i = -1;
77         for (i = 0; i < r->rewrite_nr; i++) {
78                 if (!r->rewrite[i])
79                         continue;
80                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
81                         if (starts_with(url, r->rewrite[i]->instead_of[j].s) &&
82                             (!longest ||
83                              longest->len < r->rewrite[i]->instead_of[j].len)) {
84                                 longest = &(r->rewrite[i]->instead_of[j]);
85                                 longest_i = i;
86                         }
87                 }
88         }
89         if (!longest)
90                 return url;
91
92         ret = xmalloc(r->rewrite[longest_i]->baselen +
93                      (strlen(url) - longest->len) + 1);
94         strcpy(ret, r->rewrite[longest_i]->base);
95         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
96         return ret;
97 }
98
99 static void add_push_refspec(struct remote *remote, const char *ref)
100 {
101         ALLOC_GROW(remote->push_refspec,
102                    remote->push_refspec_nr + 1,
103                    remote->push_refspec_alloc);
104         remote->push_refspec[remote->push_refspec_nr++] = ref;
105 }
106
107 static void add_fetch_refspec(struct remote *remote, const char *ref)
108 {
109         ALLOC_GROW(remote->fetch_refspec,
110                    remote->fetch_refspec_nr + 1,
111                    remote->fetch_refspec_alloc);
112         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
113 }
114
115 static void add_url(struct remote *remote, const char *url)
116 {
117         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
118         remote->url[remote->url_nr++] = url;
119 }
120
121 static void add_pushurl(struct remote *remote, const char *pushurl)
122 {
123         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
124         remote->pushurl[remote->pushurl_nr++] = pushurl;
125 }
126
127 static void add_pushurl_alias(struct remote *remote, const char *url)
128 {
129         const char *pushurl = alias_url(url, &rewrites_push);
130         if (pushurl != url)
131                 add_pushurl(remote, pushurl);
132 }
133
134 static void add_url_alias(struct remote *remote, const char *url)
135 {
136         add_url(remote, alias_url(url, &rewrites));
137         add_pushurl_alias(remote, url);
138 }
139
140 struct remotes_hash_key {
141         const char *str;
142         int len;
143 };
144
145 static int remotes_hash_cmp(const struct remote *a, const struct remote *b, const struct remotes_hash_key *key)
146 {
147         if (key)
148                 return strncmp(a->name, key->str, key->len) || a->name[key->len];
149         else
150                 return strcmp(a->name, b->name);
151 }
152
153 static inline void init_remotes_hash(void)
154 {
155         if (!remotes_hash.cmpfn)
156                 hashmap_init(&remotes_hash, (hashmap_cmp_fn)remotes_hash_cmp, 0);
157 }
158
159 static struct remote *make_remote(const char *name, int len)
160 {
161         struct remote *ret, *replaced;
162         struct remotes_hash_key lookup;
163         struct hashmap_entry lookup_entry;
164
165         if (!len)
166                 len = strlen(name);
167
168         init_remotes_hash();
169         lookup.str = name;
170         lookup.len = len;
171         hashmap_entry_init(&lookup_entry, memhash(name, len));
172
173         if ((ret = hashmap_get(&remotes_hash, &lookup_entry, &lookup)) != NULL)
174                 return ret;
175
176         ret = xcalloc(1, sizeof(struct remote));
177         ret->prune = -1;  /* unspecified */
178         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
179         remotes[remotes_nr++] = ret;
180         ret->name = xstrndup(name, len);
181
182         hashmap_entry_init(ret, lookup_entry.hash);
183         replaced = hashmap_put(&remotes_hash, ret);
184         assert(replaced == NULL);  /* no previous entry overwritten */
185         return ret;
186 }
187
188 static void add_merge(struct branch *branch, const char *name)
189 {
190         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
191                    branch->merge_alloc);
192         branch->merge_name[branch->merge_nr++] = name;
193 }
194
195 static struct branch *make_branch(const char *name, int len)
196 {
197         struct branch *ret;
198         int i;
199
200         for (i = 0; i < branches_nr; i++) {
201                 if (len ? (!strncmp(name, branches[i]->name, len) &&
202                            !branches[i]->name[len]) :
203                     !strcmp(name, branches[i]->name))
204                         return branches[i];
205         }
206
207         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
208         ret = xcalloc(1, sizeof(struct branch));
209         branches[branches_nr++] = ret;
210         if (len)
211                 ret->name = xstrndup(name, len);
212         else
213                 ret->name = xstrdup(name);
214         ret->refname = xstrfmt("refs/heads/%s", ret->name);
215
216         return ret;
217 }
218
219 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
220 {
221         struct rewrite *ret;
222         int i;
223
224         for (i = 0; i < r->rewrite_nr; i++) {
225                 if (len
226                     ? (len == r->rewrite[i]->baselen &&
227                        !strncmp(base, r->rewrite[i]->base, len))
228                     : !strcmp(base, r->rewrite[i]->base))
229                         return r->rewrite[i];
230         }
231
232         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
233         ret = xcalloc(1, sizeof(struct rewrite));
234         r->rewrite[r->rewrite_nr++] = ret;
235         if (len) {
236                 ret->base = xstrndup(base, len);
237                 ret->baselen = len;
238         }
239         else {
240                 ret->base = xstrdup(base);
241                 ret->baselen = strlen(base);
242         }
243         return ret;
244 }
245
246 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
247 {
248         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
249         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
250         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
251         rewrite->instead_of_nr++;
252 }
253
254 static void read_remotes_file(struct remote *remote)
255 {
256         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
257
258         if (!f)
259                 return;
260         remote->origin = REMOTE_REMOTES;
261         while (fgets(buffer, BUF_SIZE, f)) {
262                 int value_list;
263                 char *s, *p;
264
265                 if (starts_with(buffer, "URL:")) {
266                         value_list = 0;
267                         s = buffer + 4;
268                 } else if (starts_with(buffer, "Push:")) {
269                         value_list = 1;
270                         s = buffer + 5;
271                 } else if (starts_with(buffer, "Pull:")) {
272                         value_list = 2;
273                         s = buffer + 5;
274                 } else
275                         continue;
276
277                 while (isspace(*s))
278                         s++;
279                 if (!*s)
280                         continue;
281
282                 p = s + strlen(s);
283                 while (isspace(p[-1]))
284                         *--p = 0;
285
286                 switch (value_list) {
287                 case 0:
288                         add_url_alias(remote, xstrdup(s));
289                         break;
290                 case 1:
291                         add_push_refspec(remote, xstrdup(s));
292                         break;
293                 case 2:
294                         add_fetch_refspec(remote, xstrdup(s));
295                         break;
296                 }
297         }
298         fclose(f);
299 }
300
301 static void read_branches_file(struct remote *remote)
302 {
303         char *frag;
304         struct strbuf branch = STRBUF_INIT;
305         int n = 1000;
306         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
307         char *s, *p;
308         int len;
309
310         if (!f)
311                 return;
312         s = fgets(buffer, BUF_SIZE, f);
313         fclose(f);
314         if (!s)
315                 return;
316         while (isspace(*s))
317                 s++;
318         if (!*s)
319                 return;
320         remote->origin = REMOTE_BRANCHES;
321         p = s + strlen(s);
322         while (isspace(p[-1]))
323                 *--p = 0;
324         len = p - s;
325         p = xmalloc(len + 1);
326         strcpy(p, s);
327
328         /*
329          * The branches file would have URL and optionally
330          * #branch specified.  The "master" (or specified) branch is
331          * fetched and stored in the local branch of the same name.
332          */
333         frag = strchr(p, '#');
334         if (frag) {
335                 *(frag++) = '\0';
336                 strbuf_addf(&branch, "refs/heads/%s", frag);
337         } else
338                 strbuf_addstr(&branch, "refs/heads/master");
339
340         strbuf_addf(&branch, ":refs/heads/%s", remote->name);
341         add_url_alias(remote, p);
342         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
343         /*
344          * Cogito compatible push: push current HEAD to remote #branch
345          * (master if missing)
346          */
347         strbuf_init(&branch, 0);
348         strbuf_addstr(&branch, "HEAD");
349         if (frag)
350                 strbuf_addf(&branch, ":refs/heads/%s", frag);
351         else
352                 strbuf_addstr(&branch, ":refs/heads/master");
353         add_push_refspec(remote, strbuf_detach(&branch, NULL));
354         remote->fetch_tags = 1; /* always auto-follow */
355 }
356
357 static int handle_config(const char *key, const char *value, void *cb)
358 {
359         const char *name;
360         const char *subkey;
361         struct remote *remote;
362         struct branch *branch;
363         if (starts_with(key, "branch.")) {
364                 name = key + 7;
365                 subkey = strrchr(name, '.');
366                 if (!subkey)
367                         return 0;
368                 branch = make_branch(name, subkey - name);
369                 if (!strcmp(subkey, ".remote")) {
370                         if (git_config_string(&branch->remote_name, key, value))
371                                 return -1;
372                         if (branch == current_branch) {
373                                 default_remote_name = branch->remote_name;
374                                 explicit_default_remote_name = 1;
375                         }
376                 } else if (!strcmp(subkey, ".pushremote")) {
377                         if (branch == current_branch)
378                                 if (git_config_string(&branch_pushremote_name, key, value))
379                                         return -1;
380                 } else if (!strcmp(subkey, ".merge")) {
381                         if (!value)
382                                 return config_error_nonbool(key);
383                         add_merge(branch, xstrdup(value));
384                 }
385                 return 0;
386         }
387         if (starts_with(key, "url.")) {
388                 struct rewrite *rewrite;
389                 name = key + 4;
390                 subkey = strrchr(name, '.');
391                 if (!subkey)
392                         return 0;
393                 if (!strcmp(subkey, ".insteadof")) {
394                         rewrite = make_rewrite(&rewrites, name, subkey - name);
395                         if (!value)
396                                 return config_error_nonbool(key);
397                         add_instead_of(rewrite, xstrdup(value));
398                 } else if (!strcmp(subkey, ".pushinsteadof")) {
399                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
400                         if (!value)
401                                 return config_error_nonbool(key);
402                         add_instead_of(rewrite, xstrdup(value));
403                 }
404         }
405
406         if (!starts_with(key,  "remote."))
407                 return 0;
408         name = key + 7;
409
410         /* Handle remote.* variables */
411         if (!strcmp(name, "pushdefault"))
412                 return git_config_string(&pushremote_name, key, value);
413
414         /* Handle remote.<name>.* variables */
415         if (*name == '/') {
416                 warning("Config remote shorthand cannot begin with '/': %s",
417                         name);
418                 return 0;
419         }
420         subkey = strrchr(name, '.');
421         if (!subkey)
422                 return 0;
423         remote = make_remote(name, subkey - name);
424         remote->origin = REMOTE_CONFIG;
425         if (!strcmp(subkey, ".mirror"))
426                 remote->mirror = git_config_bool(key, value);
427         else if (!strcmp(subkey, ".skipdefaultupdate"))
428                 remote->skip_default_update = git_config_bool(key, value);
429         else if (!strcmp(subkey, ".skipfetchall"))
430                 remote->skip_default_update = git_config_bool(key, value);
431         else if (!strcmp(subkey, ".prune"))
432                 remote->prune = git_config_bool(key, value);
433         else if (!strcmp(subkey, ".url")) {
434                 const char *v;
435                 if (git_config_string(&v, key, value))
436                         return -1;
437                 add_url(remote, v);
438         } else if (!strcmp(subkey, ".pushurl")) {
439                 const char *v;
440                 if (git_config_string(&v, key, value))
441                         return -1;
442                 add_pushurl(remote, v);
443         } else if (!strcmp(subkey, ".push")) {
444                 const char *v;
445                 if (git_config_string(&v, key, value))
446                         return -1;
447                 add_push_refspec(remote, v);
448         } else if (!strcmp(subkey, ".fetch")) {
449                 const char *v;
450                 if (git_config_string(&v, key, value))
451                         return -1;
452                 add_fetch_refspec(remote, v);
453         } else if (!strcmp(subkey, ".receivepack")) {
454                 const char *v;
455                 if (git_config_string(&v, key, value))
456                         return -1;
457                 if (!remote->receivepack)
458                         remote->receivepack = v;
459                 else
460                         error("more than one receivepack given, using the first");
461         } else if (!strcmp(subkey, ".uploadpack")) {
462                 const char *v;
463                 if (git_config_string(&v, key, value))
464                         return -1;
465                 if (!remote->uploadpack)
466                         remote->uploadpack = v;
467                 else
468                         error("more than one uploadpack given, using the first");
469         } else if (!strcmp(subkey, ".tagopt")) {
470                 if (!strcmp(value, "--no-tags"))
471                         remote->fetch_tags = -1;
472                 else if (!strcmp(value, "--tags"))
473                         remote->fetch_tags = 2;
474         } else if (!strcmp(subkey, ".proxy")) {
475                 return git_config_string((const char **)&remote->http_proxy,
476                                          key, value);
477         } else if (!strcmp(subkey, ".vcs")) {
478                 return git_config_string(&remote->foreign_vcs, key, value);
479         }
480         return 0;
481 }
482
483 static void alias_all_urls(void)
484 {
485         int i, j;
486         for (i = 0; i < remotes_nr; i++) {
487                 int add_pushurl_aliases;
488                 if (!remotes[i])
489                         continue;
490                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
491                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
492                 }
493                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
494                 for (j = 0; j < remotes[i]->url_nr; j++) {
495                         if (add_pushurl_aliases)
496                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
497                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
498                 }
499         }
500 }
501
502 static void read_config(void)
503 {
504         unsigned char sha1[20];
505         const char *head_ref;
506         int flag;
507         if (default_remote_name) /* did this already */
508                 return;
509         default_remote_name = "origin";
510         current_branch = NULL;
511         head_ref = resolve_ref_unsafe("HEAD", sha1, 0, &flag);
512         if (head_ref && (flag & REF_ISSYMREF) &&
513             skip_prefix(head_ref, "refs/heads/", &head_ref)) {
514                 current_branch = make_branch(head_ref, 0);
515         }
516         git_config(handle_config, NULL);
517         if (branch_pushremote_name) {
518                 free((char *)pushremote_name);
519                 pushremote_name = branch_pushremote_name;
520         }
521         alias_all_urls();
522 }
523
524 /*
525  * This function frees a refspec array.
526  * Warning: code paths should be checked to ensure that the src
527  *          and dst pointers are always freeable pointers as well
528  *          as the refspec pointer itself.
529  */
530 static void free_refspecs(struct refspec *refspec, int nr_refspec)
531 {
532         int i;
533
534         if (!refspec)
535                 return;
536
537         for (i = 0; i < nr_refspec; i++) {
538                 free(refspec[i].src);
539                 free(refspec[i].dst);
540         }
541         free(refspec);
542 }
543
544 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
545 {
546         int i;
547         struct refspec *rs = xcalloc(nr_refspec, sizeof(*rs));
548
549         for (i = 0; i < nr_refspec; i++) {
550                 size_t llen;
551                 int is_glob;
552                 const char *lhs, *rhs;
553                 int flags;
554
555                 is_glob = 0;
556
557                 lhs = refspec[i];
558                 if (*lhs == '+') {
559                         rs[i].force = 1;
560                         lhs++;
561                 }
562
563                 rhs = strrchr(lhs, ':');
564
565                 /*
566                  * Before going on, special case ":" (or "+:") as a refspec
567                  * for pushing matching refs.
568                  */
569                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
570                         rs[i].matching = 1;
571                         continue;
572                 }
573
574                 if (rhs) {
575                         size_t rlen = strlen(++rhs);
576                         is_glob = (1 <= rlen && strchr(rhs, '*'));
577                         rs[i].dst = xstrndup(rhs, rlen);
578                 }
579
580                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
581                 if (1 <= llen && memchr(lhs, '*', llen)) {
582                         if ((rhs && !is_glob) || (!rhs && fetch))
583                                 goto invalid;
584                         is_glob = 1;
585                 } else if (rhs && is_glob) {
586                         goto invalid;
587                 }
588
589                 rs[i].pattern = is_glob;
590                 rs[i].src = xstrndup(lhs, llen);
591                 flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
592
593                 if (fetch) {
594                         unsigned char unused[40];
595
596                         /* LHS */
597                         if (!*rs[i].src)
598                                 ; /* empty is ok; it means "HEAD" */
599                         else if (llen == 40 && !get_sha1_hex(rs[i].src, unused))
600                                 rs[i].exact_sha1 = 1; /* ok */
601                         else if (!check_refname_format(rs[i].src, flags))
602                                 ; /* valid looking ref is ok */
603                         else
604                                 goto invalid;
605                         /* RHS */
606                         if (!rs[i].dst)
607                                 ; /* missing is ok; it is the same as empty */
608                         else if (!*rs[i].dst)
609                                 ; /* empty is ok; it means "do not store" */
610                         else if (!check_refname_format(rs[i].dst, flags))
611                                 ; /* valid looking ref is ok */
612                         else
613                                 goto invalid;
614                 } else {
615                         /*
616                          * LHS
617                          * - empty is allowed; it means delete.
618                          * - when wildcarded, it must be a valid looking ref.
619                          * - otherwise, it must be an extended SHA-1, but
620                          *   there is no existing way to validate this.
621                          */
622                         if (!*rs[i].src)
623                                 ; /* empty is ok */
624                         else if (is_glob) {
625                                 if (check_refname_format(rs[i].src, flags))
626                                         goto invalid;
627                         }
628                         else
629                                 ; /* anything goes, for now */
630                         /*
631                          * RHS
632                          * - missing is allowed, but LHS then must be a
633                          *   valid looking ref.
634                          * - empty is not allowed.
635                          * - otherwise it must be a valid looking ref.
636                          */
637                         if (!rs[i].dst) {
638                                 if (check_refname_format(rs[i].src, flags))
639                                         goto invalid;
640                         } else if (!*rs[i].dst) {
641                                 goto invalid;
642                         } else {
643                                 if (check_refname_format(rs[i].dst, flags))
644                                         goto invalid;
645                         }
646                 }
647         }
648         return rs;
649
650  invalid:
651         if (verify) {
652                 /*
653                  * nr_refspec must be greater than zero and i must be valid
654                  * since it is only possible to reach this point from within
655                  * the for loop above.
656                  */
657                 free_refspecs(rs, i+1);
658                 return NULL;
659         }
660         die("Invalid refspec '%s'", refspec[i]);
661 }
662
663 int valid_fetch_refspec(const char *fetch_refspec_str)
664 {
665         struct refspec *refspec;
666
667         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
668         free_refspecs(refspec, 1);
669         return !!refspec;
670 }
671
672 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
673 {
674         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
675 }
676
677 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
678 {
679         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
680 }
681
682 void free_refspec(int nr_refspec, struct refspec *refspec)
683 {
684         int i;
685         for (i = 0; i < nr_refspec; i++) {
686                 free(refspec[i].src);
687                 free(refspec[i].dst);
688         }
689         free(refspec);
690 }
691
692 static int valid_remote_nick(const char *name)
693 {
694         if (!name[0] || is_dot_or_dotdot(name))
695                 return 0;
696         return !strchr(name, '/'); /* no slash */
697 }
698
699 static struct remote *remote_get_1(const char *name, const char *pushremote_name)
700 {
701         struct remote *ret;
702         int name_given = 0;
703
704         if (name)
705                 name_given = 1;
706         else {
707                 if (pushremote_name) {
708                         name = pushremote_name;
709                         name_given = 1;
710                 } else {
711                         name = default_remote_name;
712                         name_given = explicit_default_remote_name;
713                 }
714         }
715
716         ret = make_remote(name, 0);
717         if (valid_remote_nick(name)) {
718                 if (!valid_remote(ret))
719                         read_remotes_file(ret);
720                 if (!valid_remote(ret))
721                         read_branches_file(ret);
722         }
723         if (name_given && !valid_remote(ret))
724                 add_url_alias(ret, name);
725         if (!valid_remote(ret))
726                 return NULL;
727         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
728         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
729         return ret;
730 }
731
732 struct remote *remote_get(const char *name)
733 {
734         read_config();
735         return remote_get_1(name, NULL);
736 }
737
738 struct remote *pushremote_get(const char *name)
739 {
740         read_config();
741         return remote_get_1(name, pushremote_name);
742 }
743
744 int remote_is_configured(const char *name)
745 {
746         struct remotes_hash_key lookup;
747         struct hashmap_entry lookup_entry;
748         read_config();
749
750         init_remotes_hash();
751         lookup.str = name;
752         lookup.len = strlen(name);
753         hashmap_entry_init(&lookup_entry, memhash(name, lookup.len));
754
755         return hashmap_get(&remotes_hash, &lookup_entry, &lookup) != NULL;
756 }
757
758 int for_each_remote(each_remote_fn fn, void *priv)
759 {
760         int i, result = 0;
761         read_config();
762         for (i = 0; i < remotes_nr && !result; i++) {
763                 struct remote *r = remotes[i];
764                 if (!r)
765                         continue;
766                 if (!r->fetch)
767                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
768                                                        r->fetch_refspec);
769                 if (!r->push)
770                         r->push = parse_push_refspec(r->push_refspec_nr,
771                                                      r->push_refspec);
772                 result = fn(r, priv);
773         }
774         return result;
775 }
776
777 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
778 {
779         if (strcmp(ref1->name, ref2->name)) {
780                 if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
781                     ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
782                         die(_("Cannot fetch both %s and %s to %s"),
783                             ref1->name, ref2->name, ref2->peer_ref->name);
784                 } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
785                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
786                         warning(_("%s usually tracks %s, not %s"),
787                                 ref2->peer_ref->name, ref2->name, ref1->name);
788                 } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
789                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
790                         die(_("%s tracks both %s and %s"),
791                             ref2->peer_ref->name, ref1->name, ref2->name);
792                 } else {
793                         /*
794                          * This last possibility doesn't occur because
795                          * FETCH_HEAD_IGNORE entries always appear at
796                          * the end of the list.
797                          */
798                         die(_("Internal error"));
799                 }
800         }
801         free(ref2->peer_ref);
802         free(ref2);
803 }
804
805 struct ref *ref_remove_duplicates(struct ref *ref_map)
806 {
807         struct string_list refs = STRING_LIST_INIT_NODUP;
808         struct ref *retval = NULL;
809         struct ref **p = &retval;
810
811         while (ref_map) {
812                 struct ref *ref = ref_map;
813
814                 ref_map = ref_map->next;
815                 ref->next = NULL;
816
817                 if (!ref->peer_ref) {
818                         *p = ref;
819                         p = &ref->next;
820                 } else {
821                         struct string_list_item *item =
822                                 string_list_insert(&refs, ref->peer_ref->name);
823
824                         if (item->util) {
825                                 /* Entry already existed */
826                                 handle_duplicate((struct ref *)item->util, ref);
827                         } else {
828                                 *p = ref;
829                                 p = &ref->next;
830                                 item->util = ref;
831                         }
832                 }
833         }
834
835         string_list_clear(&refs, 0);
836         return retval;
837 }
838
839 int remote_has_url(struct remote *remote, const char *url)
840 {
841         int i;
842         for (i = 0; i < remote->url_nr; i++) {
843                 if (!strcmp(remote->url[i], url))
844                         return 1;
845         }
846         return 0;
847 }
848
849 static int match_name_with_pattern(const char *key, const char *name,
850                                    const char *value, char **result)
851 {
852         const char *kstar = strchr(key, '*');
853         size_t klen;
854         size_t ksuffixlen;
855         size_t namelen;
856         int ret;
857         if (!kstar)
858                 die("Key '%s' of pattern had no '*'", key);
859         klen = kstar - key;
860         ksuffixlen = strlen(kstar + 1);
861         namelen = strlen(name);
862         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
863                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
864         if (ret && value) {
865                 const char *vstar = strchr(value, '*');
866                 size_t vlen;
867                 size_t vsuffixlen;
868                 if (!vstar)
869                         die("Value '%s' of pattern has no '*'", value);
870                 vlen = vstar - value;
871                 vsuffixlen = strlen(vstar + 1);
872                 *result = xmalloc(vlen + vsuffixlen +
873                                   strlen(name) -
874                                   klen - ksuffixlen + 1);
875                 strncpy(*result, value, vlen);
876                 strncpy(*result + vlen,
877                         name + klen, namelen - klen - ksuffixlen);
878                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
879                        vstar + 1);
880         }
881         return ret;
882 }
883
884 static void query_refspecs_multiple(struct refspec *refs, int ref_count, struct refspec *query, struct string_list *results)
885 {
886         int i;
887         int find_src = !query->src;
888
889         if (find_src && !query->dst)
890                 error("query_refspecs_multiple: need either src or dst");
891
892         for (i = 0; i < ref_count; i++) {
893                 struct refspec *refspec = &refs[i];
894                 const char *key = find_src ? refspec->dst : refspec->src;
895                 const char *value = find_src ? refspec->src : refspec->dst;
896                 const char *needle = find_src ? query->dst : query->src;
897                 char **result = find_src ? &query->src : &query->dst;
898
899                 if (!refspec->dst)
900                         continue;
901                 if (refspec->pattern) {
902                         if (match_name_with_pattern(key, needle, value, result))
903                                 string_list_append_nodup(results, *result);
904                 } else if (!strcmp(needle, key)) {
905                         string_list_append(results, value);
906                 }
907         }
908 }
909
910 int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
911 {
912         int i;
913         int find_src = !query->src;
914         const char *needle = find_src ? query->dst : query->src;
915         char **result = find_src ? &query->src : &query->dst;
916
917         if (find_src && !query->dst)
918                 return error("query_refspecs: need either src or dst");
919
920         for (i = 0; i < ref_count; i++) {
921                 struct refspec *refspec = &refs[i];
922                 const char *key = find_src ? refspec->dst : refspec->src;
923                 const char *value = find_src ? refspec->src : refspec->dst;
924
925                 if (!refspec->dst)
926                         continue;
927                 if (refspec->pattern) {
928                         if (match_name_with_pattern(key, needle, value, result)) {
929                                 query->force = refspec->force;
930                                 return 0;
931                         }
932                 } else if (!strcmp(needle, key)) {
933                         *result = xstrdup(value);
934                         query->force = refspec->force;
935                         return 0;
936                 }
937         }
938         return -1;
939 }
940
941 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
942                      const char *name)
943 {
944         struct refspec query;
945
946         memset(&query, 0, sizeof(struct refspec));
947         query.src = (char *)name;
948
949         if (query_refspecs(refspecs, nr_refspec, &query))
950                 return NULL;
951
952         return query.dst;
953 }
954
955 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
956 {
957         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
958 }
959
960 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
961                 const char *name)
962 {
963         size_t len = strlen(name);
964         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
965         memcpy(ref->name, prefix, prefixlen);
966         memcpy(ref->name + prefixlen, name, len);
967         return ref;
968 }
969
970 struct ref *alloc_ref(const char *name)
971 {
972         return alloc_ref_with_prefix("", 0, name);
973 }
974
975 struct ref *copy_ref(const struct ref *ref)
976 {
977         struct ref *cpy;
978         size_t len;
979         if (!ref)
980                 return NULL;
981         len = strlen(ref->name);
982         cpy = xmalloc(sizeof(struct ref) + len + 1);
983         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
984         cpy->next = NULL;
985         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
986         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
987         cpy->peer_ref = copy_ref(ref->peer_ref);
988         return cpy;
989 }
990
991 struct ref *copy_ref_list(const struct ref *ref)
992 {
993         struct ref *ret = NULL;
994         struct ref **tail = &ret;
995         while (ref) {
996                 *tail = copy_ref(ref);
997                 ref = ref->next;
998                 tail = &((*tail)->next);
999         }
1000         return ret;
1001 }
1002
1003 static void free_ref(struct ref *ref)
1004 {
1005         if (!ref)
1006                 return;
1007         free_ref(ref->peer_ref);
1008         free(ref->remote_status);
1009         free(ref->symref);
1010         free(ref);
1011 }
1012
1013 void free_refs(struct ref *ref)
1014 {
1015         struct ref *next;
1016         while (ref) {
1017                 next = ref->next;
1018                 free_ref(ref);
1019                 ref = next;
1020         }
1021 }
1022
1023 int ref_compare_name(const void *va, const void *vb)
1024 {
1025         const struct ref *a = va, *b = vb;
1026         return strcmp(a->name, b->name);
1027 }
1028
1029 static void *ref_list_get_next(const void *a)
1030 {
1031         return ((const struct ref *)a)->next;
1032 }
1033
1034 static void ref_list_set_next(void *a, void *next)
1035 {
1036         ((struct ref *)a)->next = next;
1037 }
1038
1039 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
1040 {
1041         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
1042 }
1043
1044 int count_refspec_match(const char *pattern,
1045                         struct ref *refs,
1046                         struct ref **matched_ref)
1047 {
1048         int patlen = strlen(pattern);
1049         struct ref *matched_weak = NULL;
1050         struct ref *matched = NULL;
1051         int weak_match = 0;
1052         int match = 0;
1053
1054         for (weak_match = match = 0; refs; refs = refs->next) {
1055                 char *name = refs->name;
1056                 int namelen = strlen(name);
1057
1058                 if (!refname_match(pattern, name))
1059                         continue;
1060
1061                 /* A match is "weak" if it is with refs outside
1062                  * heads or tags, and did not specify the pattern
1063                  * in full (e.g. "refs/remotes/origin/master") or at
1064                  * least from the toplevel (e.g. "remotes/origin/master");
1065                  * otherwise "git push $URL master" would result in
1066                  * ambiguity between remotes/origin/master and heads/master
1067                  * at the remote site.
1068                  */
1069                 if (namelen != patlen &&
1070                     patlen != namelen - 5 &&
1071                     !starts_with(name, "refs/heads/") &&
1072                     !starts_with(name, "refs/tags/")) {
1073                         /* We want to catch the case where only weak
1074                          * matches are found and there are multiple
1075                          * matches, and where more than one strong
1076                          * matches are found, as ambiguous.  One
1077                          * strong match with zero or more weak matches
1078                          * are acceptable as a unique match.
1079                          */
1080                         matched_weak = refs;
1081                         weak_match++;
1082                 }
1083                 else {
1084                         matched = refs;
1085                         match++;
1086                 }
1087         }
1088         if (!matched) {
1089                 if (matched_ref)
1090                         *matched_ref = matched_weak;
1091                 return weak_match;
1092         }
1093         else {
1094                 if (matched_ref)
1095                         *matched_ref = matched;
1096                 return match;
1097         }
1098 }
1099
1100 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1101 {
1102         **tail = ref;
1103         while (ref->next)
1104                 ref = ref->next;
1105         *tail = &ref->next;
1106 }
1107
1108 static struct ref *alloc_delete_ref(void)
1109 {
1110         struct ref *ref = alloc_ref("(delete)");
1111         hashclr(ref->new_sha1);
1112         return ref;
1113 }
1114
1115 static int try_explicit_object_name(const char *name,
1116                                     struct ref **match)
1117 {
1118         unsigned char sha1[20];
1119
1120         if (!*name) {
1121                 if (match)
1122                         *match = alloc_delete_ref();
1123                 return 0;
1124         }
1125
1126         if (get_sha1(name, sha1))
1127                 return -1;
1128
1129         if (match) {
1130                 *match = alloc_ref(name);
1131                 hashcpy((*match)->new_sha1, sha1);
1132         }
1133         return 0;
1134 }
1135
1136 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1137 {
1138         struct ref *ret = alloc_ref(name);
1139         tail_link_ref(ret, tail);
1140         return ret;
1141 }
1142
1143 static char *guess_ref(const char *name, struct ref *peer)
1144 {
1145         struct strbuf buf = STRBUF_INIT;
1146         unsigned char sha1[20];
1147
1148         const char *r = resolve_ref_unsafe(peer->name, sha1, 1, NULL);
1149         if (!r)
1150                 return NULL;
1151
1152         if (starts_with(r, "refs/heads/"))
1153                 strbuf_addstr(&buf, "refs/heads/");
1154         else if (starts_with(r, "refs/tags/"))
1155                 strbuf_addstr(&buf, "refs/tags/");
1156         else
1157                 return NULL;
1158
1159         strbuf_addstr(&buf, name);
1160         return strbuf_detach(&buf, NULL);
1161 }
1162
1163 static int match_explicit_lhs(struct ref *src,
1164                               struct refspec *rs,
1165                               struct ref **match,
1166                               int *allocated_match)
1167 {
1168         switch (count_refspec_match(rs->src, src, match)) {
1169         case 1:
1170                 if (allocated_match)
1171                         *allocated_match = 0;
1172                 return 0;
1173         case 0:
1174                 /* The source could be in the get_sha1() format
1175                  * not a reference name.  :refs/other is a
1176                  * way to delete 'other' ref at the remote end.
1177                  */
1178                 if (try_explicit_object_name(rs->src, match) < 0)
1179                         return error("src refspec %s does not match any.", rs->src);
1180                 if (allocated_match)
1181                         *allocated_match = 1;
1182                 return 0;
1183         default:
1184                 return error("src refspec %s matches more than one.", rs->src);
1185         }
1186 }
1187
1188 static int match_explicit(struct ref *src, struct ref *dst,
1189                           struct ref ***dst_tail,
1190                           struct refspec *rs)
1191 {
1192         struct ref *matched_src, *matched_dst;
1193         int allocated_src;
1194
1195         const char *dst_value = rs->dst;
1196         char *dst_guess;
1197
1198         if (rs->pattern || rs->matching)
1199                 return 0;
1200
1201         matched_src = matched_dst = NULL;
1202         if (match_explicit_lhs(src, rs, &matched_src, &allocated_src) < 0)
1203                 return -1;
1204
1205         if (!dst_value) {
1206                 unsigned char sha1[20];
1207                 int flag;
1208
1209                 dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
1210                 if (!dst_value ||
1211                     ((flag & REF_ISSYMREF) &&
1212                      !starts_with(dst_value, "refs/heads/")))
1213                         die("%s cannot be resolved to branch.",
1214                             matched_src->name);
1215         }
1216
1217         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1218         case 1:
1219                 break;
1220         case 0:
1221                 if (starts_with(dst_value, "refs/"))
1222                         matched_dst = make_linked_ref(dst_value, dst_tail);
1223                 else if (is_null_sha1(matched_src->new_sha1))
1224                         error("unable to delete '%s': remote ref does not exist",
1225                               dst_value);
1226                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1227                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1228                 else
1229                         error("unable to push to unqualified destination: %s\n"
1230                               "The destination refspec neither matches an "
1231                               "existing ref on the remote nor\n"
1232                               "begins with refs/, and we are unable to "
1233                               "guess a prefix based on the source ref.",
1234                               dst_value);
1235                 break;
1236         default:
1237                 matched_dst = NULL;
1238                 error("dst refspec %s matches more than one.",
1239                       dst_value);
1240                 break;
1241         }
1242         if (!matched_dst)
1243                 return -1;
1244         if (matched_dst->peer_ref)
1245                 return error("dst ref %s receives from more than one src.",
1246                       matched_dst->name);
1247         else {
1248                 matched_dst->peer_ref = allocated_src ?
1249                                         matched_src :
1250                                         copy_ref(matched_src);
1251                 matched_dst->force = rs->force;
1252         }
1253         return 0;
1254 }
1255
1256 static int match_explicit_refs(struct ref *src, struct ref *dst,
1257                                struct ref ***dst_tail, struct refspec *rs,
1258                                int rs_nr)
1259 {
1260         int i, errs;
1261         for (i = errs = 0; i < rs_nr; i++)
1262                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1263         return errs;
1264 }
1265
1266 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1267                 int send_mirror, int direction, const struct refspec **ret_pat)
1268 {
1269         const struct refspec *pat;
1270         char *name;
1271         int i;
1272         int matching_refs = -1;
1273         for (i = 0; i < rs_nr; i++) {
1274                 if (rs[i].matching &&
1275                     (matching_refs == -1 || rs[i].force)) {
1276                         matching_refs = i;
1277                         continue;
1278                 }
1279
1280                 if (rs[i].pattern) {
1281                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1282                         int match;
1283                         if (direction == FROM_SRC)
1284                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1285                         else
1286                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1287                         if (match) {
1288                                 matching_refs = i;
1289                                 break;
1290                         }
1291                 }
1292         }
1293         if (matching_refs == -1)
1294                 return NULL;
1295
1296         pat = rs + matching_refs;
1297         if (pat->matching) {
1298                 /*
1299                  * "matching refs"; traditionally we pushed everything
1300                  * including refs outside refs/heads/ hierarchy, but
1301                  * that does not make much sense these days.
1302                  */
1303                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1304                         return NULL;
1305                 name = xstrdup(ref->name);
1306         }
1307         if (ret_pat)
1308                 *ret_pat = pat;
1309         return name;
1310 }
1311
1312 static struct ref **tail_ref(struct ref **head)
1313 {
1314         struct ref **tail = head;
1315         while (*tail)
1316                 tail = &((*tail)->next);
1317         return tail;
1318 }
1319
1320 struct tips {
1321         struct commit **tip;
1322         int nr, alloc;
1323 };
1324
1325 static void add_to_tips(struct tips *tips, const unsigned char *sha1)
1326 {
1327         struct commit *commit;
1328
1329         if (is_null_sha1(sha1))
1330                 return;
1331         commit = lookup_commit_reference_gently(sha1, 1);
1332         if (!commit || (commit->object.flags & TMP_MARK))
1333                 return;
1334         commit->object.flags |= TMP_MARK;
1335         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1336         tips->tip[tips->nr++] = commit;
1337 }
1338
1339 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1340 {
1341         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1342         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1343         struct string_list_item *item;
1344         struct ref *ref;
1345         struct tips sent_tips;
1346
1347         /*
1348          * Collect everything we know they would have at the end of
1349          * this push, and collect all tags they have.
1350          */
1351         memset(&sent_tips, 0, sizeof(sent_tips));
1352         for (ref = *dst; ref; ref = ref->next) {
1353                 if (ref->peer_ref &&
1354                     !is_null_sha1(ref->peer_ref->new_sha1))
1355                         add_to_tips(&sent_tips, ref->peer_ref->new_sha1);
1356                 else
1357                         add_to_tips(&sent_tips, ref->old_sha1);
1358                 if (starts_with(ref->name, "refs/tags/"))
1359                         string_list_append(&dst_tag, ref->name);
1360         }
1361         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1362
1363         sort_string_list(&dst_tag);
1364
1365         /* Collect tags they do not have. */
1366         for (ref = src; ref; ref = ref->next) {
1367                 if (!starts_with(ref->name, "refs/tags/"))
1368                         continue; /* not a tag */
1369                 if (string_list_has_string(&dst_tag, ref->name))
1370                         continue; /* they already have it */
1371                 if (sha1_object_info(ref->new_sha1, NULL) != OBJ_TAG)
1372                         continue; /* be conservative */
1373                 item = string_list_append(&src_tag, ref->name);
1374                 item->util = ref;
1375         }
1376         string_list_clear(&dst_tag, 0);
1377
1378         /*
1379          * At this point, src_tag lists tags that are missing from
1380          * dst, and sent_tips lists the tips we are pushing or those
1381          * that we know they already have. An element in the src_tag
1382          * that is an ancestor of any of the sent_tips needs to be
1383          * sent to the other side.
1384          */
1385         if (sent_tips.nr) {
1386                 for_each_string_list_item(item, &src_tag) {
1387                         struct ref *ref = item->util;
1388                         struct ref *dst_ref;
1389                         struct commit *commit;
1390
1391                         if (is_null_sha1(ref->new_sha1))
1392                                 continue;
1393                         commit = lookup_commit_reference_gently(ref->new_sha1, 1);
1394                         if (!commit)
1395                                 /* not pushing a commit, which is not an error */
1396                                 continue;
1397
1398                         /*
1399                          * Is this tag, which they do not have, reachable from
1400                          * any of the commits we are sending?
1401                          */
1402                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1403                                 continue;
1404
1405                         /* Add it in */
1406                         dst_ref = make_linked_ref(ref->name, dst_tail);
1407                         hashcpy(dst_ref->new_sha1, ref->new_sha1);
1408                         dst_ref->peer_ref = copy_ref(ref);
1409                 }
1410         }
1411         string_list_clear(&src_tag, 0);
1412         free(sent_tips.tip);
1413 }
1414
1415 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1416 {
1417         for ( ; list; list = list->next)
1418                 if (!strcmp(list->name, name))
1419                         return (struct ref *)list;
1420         return NULL;
1421 }
1422
1423 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1424 {
1425         for ( ; ref; ref = ref->next)
1426                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1427
1428         sort_string_list(ref_index);
1429 }
1430
1431 /*
1432  * Given only the set of local refs, sanity-check the set of push
1433  * refspecs. We can't catch all errors that match_push_refs would,
1434  * but we can catch some errors early before even talking to the
1435  * remote side.
1436  */
1437 int check_push_refs(struct ref *src, int nr_refspec, const char **refspec_names)
1438 {
1439         struct refspec *refspec = parse_push_refspec(nr_refspec, refspec_names);
1440         int ret = 0;
1441         int i;
1442
1443         for (i = 0; i < nr_refspec; i++) {
1444                 struct refspec *rs = refspec + i;
1445
1446                 if (rs->pattern || rs->matching)
1447                         continue;
1448
1449                 ret |= match_explicit_lhs(src, rs, NULL, NULL);
1450         }
1451
1452         free_refspec(nr_refspec, refspec);
1453         return ret;
1454 }
1455
1456 /*
1457  * Given the set of refs the local repository has, the set of refs the
1458  * remote repository has, and the refspec used for push, determine
1459  * what remote refs we will update and with what value by setting
1460  * peer_ref (which object is being pushed) and force (if the push is
1461  * forced) in elements of "dst". The function may add new elements to
1462  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1463  */
1464 int match_push_refs(struct ref *src, struct ref **dst,
1465                     int nr_refspec, const char **refspec, int flags)
1466 {
1467         struct refspec *rs;
1468         int send_all = flags & MATCH_REFS_ALL;
1469         int send_mirror = flags & MATCH_REFS_MIRROR;
1470         int send_prune = flags & MATCH_REFS_PRUNE;
1471         int errs;
1472         static const char *default_refspec[] = { ":", NULL };
1473         struct ref *ref, **dst_tail = tail_ref(dst);
1474         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1475
1476         if (!nr_refspec) {
1477                 nr_refspec = 1;
1478                 refspec = default_refspec;
1479         }
1480         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1481         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1482
1483         /* pick the remainder */
1484         for (ref = src; ref; ref = ref->next) {
1485                 struct string_list_item *dst_item;
1486                 struct ref *dst_peer;
1487                 const struct refspec *pat = NULL;
1488                 char *dst_name;
1489
1490                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1491                 if (!dst_name)
1492                         continue;
1493
1494                 if (!dst_ref_index.nr)
1495                         prepare_ref_index(&dst_ref_index, *dst);
1496
1497                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1498                 dst_peer = dst_item ? dst_item->util : NULL;
1499                 if (dst_peer) {
1500                         if (dst_peer->peer_ref)
1501                                 /* We're already sending something to this ref. */
1502                                 goto free_name;
1503                 } else {
1504                         if (pat->matching && !(send_all || send_mirror))
1505                                 /*
1506                                  * Remote doesn't have it, and we have no
1507                                  * explicit pattern, and we don't have
1508                                  * --all or --mirror.
1509                                  */
1510                                 goto free_name;
1511
1512                         /* Create a new one and link it */
1513                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1514                         hashcpy(dst_peer->new_sha1, ref->new_sha1);
1515                         string_list_insert(&dst_ref_index,
1516                                 dst_peer->name)->util = dst_peer;
1517                 }
1518                 dst_peer->peer_ref = copy_ref(ref);
1519                 dst_peer->force = pat->force;
1520         free_name:
1521                 free(dst_name);
1522         }
1523
1524         string_list_clear(&dst_ref_index, 0);
1525
1526         if (flags & MATCH_REFS_FOLLOW_TAGS)
1527                 add_missing_tags(src, dst, &dst_tail);
1528
1529         if (send_prune) {
1530                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1531                 /* check for missing refs on the remote */
1532                 for (ref = *dst; ref; ref = ref->next) {
1533                         char *src_name;
1534
1535                         if (ref->peer_ref)
1536                                 /* We're already sending something to this ref. */
1537                                 continue;
1538
1539                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1540                         if (src_name) {
1541                                 if (!src_ref_index.nr)
1542                                         prepare_ref_index(&src_ref_index, src);
1543                                 if (!string_list_has_string(&src_ref_index,
1544                                             src_name))
1545                                         ref->peer_ref = alloc_delete_ref();
1546                                 free(src_name);
1547                         }
1548                 }
1549                 string_list_clear(&src_ref_index, 0);
1550         }
1551         if (errs)
1552                 return -1;
1553         return 0;
1554 }
1555
1556 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1557                              int force_update)
1558 {
1559         struct ref *ref;
1560
1561         for (ref = remote_refs; ref; ref = ref->next) {
1562                 int force_ref_update = ref->force || force_update;
1563                 int reject_reason = 0;
1564
1565                 if (ref->peer_ref)
1566                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1567                 else if (!send_mirror)
1568                         continue;
1569
1570                 ref->deletion = is_null_sha1(ref->new_sha1);
1571                 if (!ref->deletion &&
1572                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1573                         ref->status = REF_STATUS_UPTODATE;
1574                         continue;
1575                 }
1576
1577                 /*
1578                  * Bypass the usual "must fast-forward" check but
1579                  * replace it with a weaker "the old value must be
1580                  * this value we observed".  If the remote ref has
1581                  * moved and is now different from what we expect,
1582                  * reject any push.
1583                  *
1584                  * It also is an error if the user told us to check
1585                  * with the remote-tracking branch to find the value
1586                  * to expect, but we did not have such a tracking
1587                  * branch.
1588                  */
1589                 if (ref->expect_old_sha1) {
1590                         if (ref->expect_old_no_trackback ||
1591                             hashcmp(ref->old_sha1, ref->old_sha1_expect))
1592                                 reject_reason = REF_STATUS_REJECT_STALE;
1593                 }
1594
1595                 /*
1596                  * The usual "must fast-forward" rules.
1597                  *
1598                  * Decide whether an individual refspec A:B can be
1599                  * pushed.  The push will succeed if any of the
1600                  * following are true:
1601                  *
1602                  * (1) the remote reference B does not exist
1603                  *
1604                  * (2) the remote reference B is being removed (i.e.,
1605                  *     pushing :B where no source is specified)
1606                  *
1607                  * (3) the destination is not under refs/tags/, and
1608                  *     if the old and new value is a commit, the new
1609                  *     is a descendant of the old.
1610                  *
1611                  * (4) it is forced using the +A:B notation, or by
1612                  *     passing the --force argument
1613                  */
1614
1615                 else if (!ref->deletion && !is_null_sha1(ref->old_sha1)) {
1616                         if (starts_with(ref->name, "refs/tags/"))
1617                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1618                         else if (!has_sha1_file(ref->old_sha1))
1619                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1620                         else if (!lookup_commit_reference_gently(ref->old_sha1, 1) ||
1621                                  !lookup_commit_reference_gently(ref->new_sha1, 1))
1622                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1623                         else if (!ref_newer(ref->new_sha1, ref->old_sha1))
1624                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1625                 }
1626
1627                 /*
1628                  * "--force" will defeat any rejection implemented
1629                  * by the rules above.
1630                  */
1631                 if (!force_ref_update)
1632                         ref->status = reject_reason;
1633                 else if (reject_reason)
1634                         ref->forced_update = 1;
1635         }
1636 }
1637
1638 struct branch *branch_get(const char *name)
1639 {
1640         struct branch *ret;
1641
1642         read_config();
1643         if (!name || !*name || !strcmp(name, "HEAD"))
1644                 ret = current_branch;
1645         else
1646                 ret = make_branch(name, 0);
1647         if (ret && ret->remote_name) {
1648                 ret->remote = remote_get(ret->remote_name);
1649                 if (ret->merge_nr) {
1650                         int i;
1651                         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1652                         for (i = 0; i < ret->merge_nr; i++) {
1653                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1654                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1655                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1656                                     && !strcmp(ret->remote_name, "."))
1657                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1658                         }
1659                 }
1660         }
1661         return ret;
1662 }
1663
1664 int branch_has_merge_config(struct branch *branch)
1665 {
1666         return branch && !!branch->merge;
1667 }
1668
1669 int branch_merge_matches(struct branch *branch,
1670                                  int i,
1671                                  const char *refname)
1672 {
1673         if (!branch || i < 0 || i >= branch->merge_nr)
1674                 return 0;
1675         return refname_match(branch->merge[i]->src, refname);
1676 }
1677
1678 static int ignore_symref_update(const char *refname)
1679 {
1680         unsigned char sha1[20];
1681         int flag;
1682
1683         if (!resolve_ref_unsafe(refname, sha1, 0, &flag))
1684                 return 0; /* non-existing refs are OK */
1685         return (flag & REF_ISSYMREF);
1686 }
1687
1688 /*
1689  * Create and return a list of (struct ref) consisting of copies of
1690  * each remote_ref that matches refspec.  refspec must be a pattern.
1691  * Fill in the copies' peer_ref to describe the local tracking refs to
1692  * which they map.  Omit any references that would map to an existing
1693  * local symbolic ref.
1694  */
1695 static struct ref *get_expanded_map(const struct ref *remote_refs,
1696                                     const struct refspec *refspec)
1697 {
1698         const struct ref *ref;
1699         struct ref *ret = NULL;
1700         struct ref **tail = &ret;
1701
1702         for (ref = remote_refs; ref; ref = ref->next) {
1703                 char *expn_name = NULL;
1704
1705                 if (strchr(ref->name, '^'))
1706                         continue; /* a dereference item */
1707                 if (match_name_with_pattern(refspec->src, ref->name,
1708                                             refspec->dst, &expn_name) &&
1709                     !ignore_symref_update(expn_name)) {
1710                         struct ref *cpy = copy_ref(ref);
1711
1712                         cpy->peer_ref = alloc_ref(expn_name);
1713                         if (refspec->force)
1714                                 cpy->peer_ref->force = 1;
1715                         *tail = cpy;
1716                         tail = &cpy->next;
1717                 }
1718                 free(expn_name);
1719         }
1720
1721         return ret;
1722 }
1723
1724 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1725 {
1726         const struct ref *ref;
1727         for (ref = refs; ref; ref = ref->next) {
1728                 if (refname_match(name, ref->name))
1729                         return ref;
1730         }
1731         return NULL;
1732 }
1733
1734 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1735 {
1736         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1737
1738         if (!ref)
1739                 return NULL;
1740
1741         return copy_ref(ref);
1742 }
1743
1744 static struct ref *get_local_ref(const char *name)
1745 {
1746         if (!name || name[0] == '\0')
1747                 return NULL;
1748
1749         if (starts_with(name, "refs/"))
1750                 return alloc_ref(name);
1751
1752         if (starts_with(name, "heads/") ||
1753             starts_with(name, "tags/") ||
1754             starts_with(name, "remotes/"))
1755                 return alloc_ref_with_prefix("refs/", 5, name);
1756
1757         return alloc_ref_with_prefix("refs/heads/", 11, name);
1758 }
1759
1760 int get_fetch_map(const struct ref *remote_refs,
1761                   const struct refspec *refspec,
1762                   struct ref ***tail,
1763                   int missing_ok)
1764 {
1765         struct ref *ref_map, **rmp;
1766
1767         if (refspec->pattern) {
1768                 ref_map = get_expanded_map(remote_refs, refspec);
1769         } else {
1770                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1771
1772                 if (refspec->exact_sha1) {
1773                         ref_map = alloc_ref(name);
1774                         get_sha1_hex(name, ref_map->old_sha1);
1775                 } else {
1776                         ref_map = get_remote_ref(remote_refs, name);
1777                 }
1778                 if (!missing_ok && !ref_map)
1779                         die("Couldn't find remote ref %s", name);
1780                 if (ref_map) {
1781                         ref_map->peer_ref = get_local_ref(refspec->dst);
1782                         if (ref_map->peer_ref && refspec->force)
1783                                 ref_map->peer_ref->force = 1;
1784                 }
1785         }
1786
1787         for (rmp = &ref_map; *rmp; ) {
1788                 if ((*rmp)->peer_ref) {
1789                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1790                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1791                                 struct ref *ignore = *rmp;
1792                                 error("* Ignoring funny ref '%s' locally",
1793                                       (*rmp)->peer_ref->name);
1794                                 *rmp = (*rmp)->next;
1795                                 free(ignore->peer_ref);
1796                                 free(ignore);
1797                                 continue;
1798                         }
1799                 }
1800                 rmp = &((*rmp)->next);
1801         }
1802
1803         if (ref_map)
1804                 tail_link_ref(ref_map, tail);
1805
1806         return 0;
1807 }
1808
1809 int resolve_remote_symref(struct ref *ref, struct ref *list)
1810 {
1811         if (!ref->symref)
1812                 return 0;
1813         for (; list; list = list->next)
1814                 if (!strcmp(ref->symref, list->name)) {
1815                         hashcpy(ref->old_sha1, list->old_sha1);
1816                         return 0;
1817                 }
1818         return 1;
1819 }
1820
1821 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1822 {
1823         while (list) {
1824                 struct commit_list *temp = list;
1825                 temp->item->object.flags &= ~mark;
1826                 list = temp->next;
1827                 free(temp);
1828         }
1829 }
1830
1831 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1832 {
1833         struct object *o;
1834         struct commit *old, *new;
1835         struct commit_list *list, *used;
1836         int found = 0;
1837
1838         /*
1839          * Both new and old must be commit-ish and new is descendant of
1840          * old.  Otherwise we require --force.
1841          */
1842         o = deref_tag(parse_object(old_sha1), NULL, 0);
1843         if (!o || o->type != OBJ_COMMIT)
1844                 return 0;
1845         old = (struct commit *) o;
1846
1847         o = deref_tag(parse_object(new_sha1), NULL, 0);
1848         if (!o || o->type != OBJ_COMMIT)
1849                 return 0;
1850         new = (struct commit *) o;
1851
1852         if (parse_commit(new) < 0)
1853                 return 0;
1854
1855         used = list = NULL;
1856         commit_list_insert(new, &list);
1857         while (list) {
1858                 new = pop_most_recent_commit(&list, TMP_MARK);
1859                 commit_list_insert(new, &used);
1860                 if (new == old) {
1861                         found = 1;
1862                         break;
1863                 }
1864         }
1865         unmark_and_free(list, TMP_MARK);
1866         unmark_and_free(used, TMP_MARK);
1867         return found;
1868 }
1869
1870 /*
1871  * Compare a branch with its upstream, and save their differences (number
1872  * of commits) in *num_ours and *num_theirs.
1873  *
1874  * Return 0 if branch has no upstream (no base), -1 if upstream is missing
1875  * (with "gone" base), otherwise 1 (with base).
1876  */
1877 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1878 {
1879         unsigned char sha1[20];
1880         struct commit *ours, *theirs;
1881         char symmetric[84];
1882         struct rev_info revs;
1883         const char *rev_argv[10], *base;
1884         int rev_argc;
1885
1886         /* Cannot stat unless we are marked to build on top of somebody else. */
1887         if (!branch ||
1888             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1889                 return 0;
1890
1891         /* Cannot stat if what we used to build on no longer exists */
1892         base = branch->merge[0]->dst;
1893         if (read_ref(base, sha1))
1894                 return -1;
1895         theirs = lookup_commit_reference(sha1);
1896         if (!theirs)
1897                 return -1;
1898
1899         if (read_ref(branch->refname, sha1))
1900                 return -1;
1901         ours = lookup_commit_reference(sha1);
1902         if (!ours)
1903                 return -1;
1904
1905         /* are we the same? */
1906         if (theirs == ours) {
1907                 *num_theirs = *num_ours = 0;
1908                 return 1;
1909         }
1910
1911         /* Run "rev-list --left-right ours...theirs" internally... */
1912         rev_argc = 0;
1913         rev_argv[rev_argc++] = NULL;
1914         rev_argv[rev_argc++] = "--left-right";
1915         rev_argv[rev_argc++] = symmetric;
1916         rev_argv[rev_argc++] = "--";
1917         rev_argv[rev_argc] = NULL;
1918
1919         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1920         strcpy(symmetric + 40, "...");
1921         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1922
1923         init_revisions(&revs, NULL);
1924         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1925         if (prepare_revision_walk(&revs))
1926                 die("revision walk setup failed");
1927
1928         /* ... and count the commits on each side. */
1929         *num_ours = 0;
1930         *num_theirs = 0;
1931         while (1) {
1932                 struct commit *c = get_revision(&revs);
1933                 if (!c)
1934                         break;
1935                 if (c->object.flags & SYMMETRIC_LEFT)
1936                         (*num_ours)++;
1937                 else
1938                         (*num_theirs)++;
1939         }
1940
1941         /* clear object flags smudged by the above traversal */
1942         clear_commit_marks(ours, ALL_REV_FLAGS);
1943         clear_commit_marks(theirs, ALL_REV_FLAGS);
1944         return 1;
1945 }
1946
1947 /*
1948  * Return true when there is anything to report, otherwise false.
1949  */
1950 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1951 {
1952         int ours, theirs;
1953         char *base;
1954         int upstream_is_gone = 0;
1955
1956         switch (stat_tracking_info(branch, &ours, &theirs)) {
1957         case 0:
1958                 /* no base */
1959                 return 0;
1960         case -1:
1961                 /* with "gone" base */
1962                 upstream_is_gone = 1;
1963                 break;
1964         default:
1965                 /* with base */
1966                 break;
1967         }
1968
1969         base = shorten_unambiguous_ref(branch->merge[0]->dst, 0);
1970         if (upstream_is_gone) {
1971                 strbuf_addf(sb,
1972                         _("Your branch is based on '%s', but the upstream is gone.\n"),
1973                         base);
1974                 if (advice_status_hints)
1975                         strbuf_addf(sb,
1976                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
1977         } else if (!ours && !theirs) {
1978                 strbuf_addf(sb,
1979                         _("Your branch is up-to-date with '%s'.\n"),
1980                         base);
1981         } else if (!theirs) {
1982                 strbuf_addf(sb,
1983                         Q_("Your branch is ahead of '%s' by %d commit.\n",
1984                            "Your branch is ahead of '%s' by %d commits.\n",
1985                            ours),
1986                         base, ours);
1987                 if (advice_status_hints)
1988                         strbuf_addf(sb,
1989                                 _("  (use \"git push\" to publish your local commits)\n"));
1990         } else if (!ours) {
1991                 strbuf_addf(sb,
1992                         Q_("Your branch is behind '%s' by %d commit, "
1993                                "and can be fast-forwarded.\n",
1994                            "Your branch is behind '%s' by %d commits, "
1995                                "and can be fast-forwarded.\n",
1996                            theirs),
1997                         base, theirs);
1998                 if (advice_status_hints)
1999                         strbuf_addf(sb,
2000                                 _("  (use \"git pull\" to update your local branch)\n"));
2001         } else {
2002                 strbuf_addf(sb,
2003                         Q_("Your branch and '%s' have diverged,\n"
2004                                "and have %d and %d different commit each, "
2005                                "respectively.\n",
2006                            "Your branch and '%s' have diverged,\n"
2007                                "and have %d and %d different commits each, "
2008                                "respectively.\n",
2009                            theirs),
2010                         base, ours, theirs);
2011                 if (advice_status_hints)
2012                         strbuf_addf(sb,
2013                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
2014         }
2015         free(base);
2016         return 1;
2017 }
2018
2019 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
2020 {
2021         struct ref ***local_tail = cb_data;
2022         struct ref *ref;
2023         int len;
2024
2025         /* we already know it starts with refs/ to get here */
2026         if (check_refname_format(refname + 5, 0))
2027                 return 0;
2028
2029         len = strlen(refname) + 1;
2030         ref = xcalloc(1, sizeof(*ref) + len);
2031         hashcpy(ref->new_sha1, sha1);
2032         memcpy(ref->name, refname, len);
2033         **local_tail = ref;
2034         *local_tail = &ref->next;
2035         return 0;
2036 }
2037
2038 struct ref *get_local_heads(void)
2039 {
2040         struct ref *local_refs = NULL, **local_tail = &local_refs;
2041         for_each_ref(one_local_ref, &local_tail);
2042         return local_refs;
2043 }
2044
2045 struct ref *guess_remote_head(const struct ref *head,
2046                               const struct ref *refs,
2047                               int all)
2048 {
2049         const struct ref *r;
2050         struct ref *list = NULL;
2051         struct ref **tail = &list;
2052
2053         if (!head)
2054                 return NULL;
2055
2056         /*
2057          * Some transports support directly peeking at
2058          * where HEAD points; if that is the case, then
2059          * we don't have to guess.
2060          */
2061         if (head->symref)
2062                 return copy_ref(find_ref_by_name(refs, head->symref));
2063
2064         /* If refs/heads/master could be right, it is. */
2065         if (!all) {
2066                 r = find_ref_by_name(refs, "refs/heads/master");
2067                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
2068                         return copy_ref(r);
2069         }
2070
2071         /* Look for another ref that points there */
2072         for (r = refs; r; r = r->next) {
2073                 if (r != head &&
2074                     starts_with(r->name, "refs/heads/") &&
2075                     !hashcmp(r->old_sha1, head->old_sha1)) {
2076                         *tail = copy_ref(r);
2077                         tail = &((*tail)->next);
2078                         if (!all)
2079                                 break;
2080                 }
2081         }
2082
2083         return list;
2084 }
2085
2086 struct stale_heads_info {
2087         struct string_list *ref_names;
2088         struct ref **stale_refs_tail;
2089         struct refspec *refs;
2090         int ref_count;
2091 };
2092
2093 static int get_stale_heads_cb(const char *refname,
2094         const unsigned char *sha1, int flags, void *cb_data)
2095 {
2096         struct stale_heads_info *info = cb_data;
2097         struct string_list matches = STRING_LIST_INIT_DUP;
2098         struct refspec query;
2099         int i, stale = 1;
2100         memset(&query, 0, sizeof(struct refspec));
2101         query.dst = (char *)refname;
2102
2103         query_refspecs_multiple(info->refs, info->ref_count, &query, &matches);
2104         if (matches.nr == 0)
2105                 goto clean_exit; /* No matches */
2106
2107         /*
2108          * If we did find a suitable refspec and it's not a symref and
2109          * it's not in the list of refs that currently exist in that
2110          * remote, we consider it to be stale. In order to deal with
2111          * overlapping refspecs, we need to go over all of the
2112          * matching refs.
2113          */
2114         if (flags & REF_ISSYMREF)
2115                 goto clean_exit;
2116
2117         for (i = 0; stale && i < matches.nr; i++)
2118                 if (string_list_has_string(info->ref_names, matches.items[i].string))
2119                         stale = 0;
2120
2121         if (stale) {
2122                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2123                 hashcpy(ref->new_sha1, sha1);
2124         }
2125
2126 clean_exit:
2127         string_list_clear(&matches, 0);
2128         return 0;
2129 }
2130
2131 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
2132 {
2133         struct ref *ref, *stale_refs = NULL;
2134         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2135         struct stale_heads_info info;
2136         info.ref_names = &ref_names;
2137         info.stale_refs_tail = &stale_refs;
2138         info.refs = refs;
2139         info.ref_count = ref_count;
2140         for (ref = fetch_map; ref; ref = ref->next)
2141                 string_list_append(&ref_names, ref->name);
2142         sort_string_list(&ref_names);
2143         for_each_ref(get_stale_heads_cb, &info);
2144         string_list_clear(&ref_names, 0);
2145         return stale_refs;
2146 }
2147
2148 /*
2149  * Compare-and-swap
2150  */
2151 void clear_cas_option(struct push_cas_option *cas)
2152 {
2153         int i;
2154
2155         for (i = 0; i < cas->nr; i++)
2156                 free(cas->entry[i].refname);
2157         free(cas->entry);
2158         memset(cas, 0, sizeof(*cas));
2159 }
2160
2161 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2162                                       const char *refname,
2163                                       size_t refnamelen)
2164 {
2165         struct push_cas *entry;
2166         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2167         entry = &cas->entry[cas->nr++];
2168         memset(entry, 0, sizeof(*entry));
2169         entry->refname = xmemdupz(refname, refnamelen);
2170         return entry;
2171 }
2172
2173 int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2174 {
2175         const char *colon;
2176         struct push_cas *entry;
2177
2178         if (unset) {
2179                 /* "--no-<option>" */
2180                 clear_cas_option(cas);
2181                 return 0;
2182         }
2183
2184         if (!arg) {
2185                 /* just "--<option>" */
2186                 cas->use_tracking_for_rest = 1;
2187                 return 0;
2188         }
2189
2190         /* "--<option>=refname" or "--<option>=refname:value" */
2191         colon = strchrnul(arg, ':');
2192         entry = add_cas_entry(cas, arg, colon - arg);
2193         if (!*colon)
2194                 entry->use_tracking = 1;
2195         else if (get_sha1(colon + 1, entry->expect))
2196                 return error("cannot parse expected object name '%s'", colon + 1);
2197         return 0;
2198 }
2199
2200 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2201 {
2202         return parse_push_cas_option(opt->value, arg, unset);
2203 }
2204
2205 int is_empty_cas(const struct push_cas_option *cas)
2206 {
2207         return !cas->use_tracking_for_rest && !cas->nr;
2208 }
2209
2210 /*
2211  * Look at remote.fetch refspec and see if we have a remote
2212  * tracking branch for the refname there.  Fill its current
2213  * value in sha1[].
2214  * If we cannot do so, return negative to signal an error.
2215  */
2216 static int remote_tracking(struct remote *remote, const char *refname,
2217                            unsigned char sha1[20])
2218 {
2219         char *dst;
2220
2221         dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
2222         if (!dst)
2223                 return -1; /* no tracking ref for refname at remote */
2224         if (read_ref(dst, sha1))
2225                 return -1; /* we know what the tracking ref is but we cannot read it */
2226         return 0;
2227 }
2228
2229 static void apply_cas(struct push_cas_option *cas,
2230                       struct remote *remote,
2231                       struct ref *ref)
2232 {
2233         int i;
2234
2235         /* Find an explicit --<option>=<name>[:<value>] entry */
2236         for (i = 0; i < cas->nr; i++) {
2237                 struct push_cas *entry = &cas->entry[i];
2238                 if (!refname_match(entry->refname, ref->name))
2239                         continue;
2240                 ref->expect_old_sha1 = 1;
2241                 if (!entry->use_tracking)
2242                         hashcpy(ref->old_sha1_expect, cas->entry[i].expect);
2243                 else if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2244                         ref->expect_old_no_trackback = 1;
2245                 return;
2246         }
2247
2248         /* Are we using "--<option>" to cover all? */
2249         if (!cas->use_tracking_for_rest)
2250                 return;
2251
2252         ref->expect_old_sha1 = 1;
2253         if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2254                 ref->expect_old_no_trackback = 1;
2255 }
2256
2257 void apply_push_cas(struct push_cas_option *cas,
2258                     struct remote *remote,
2259                     struct ref *remote_refs)
2260 {
2261         struct ref *ref;
2262         for (ref = remote_refs; ref; ref = ref->next)
2263                 apply_cas(cas, remote, ref);
2264 }