Merge branch 'bc/sha1-header-selection-with-cpp-macros'
[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 #include "argv-array.h"
12
13 enum map_direction { FROM_SRC, FROM_DST };
14
15 static struct refspec s_tag_refspec = {
16         0,
17         1,
18         0,
19         0,
20         "refs/tags/*",
21         "refs/tags/*"
22 };
23
24 const struct refspec *tag_refspec = &s_tag_refspec;
25
26 struct counted_string {
27         size_t len;
28         const char *s;
29 };
30 struct rewrite {
31         const char *base;
32         size_t baselen;
33         struct counted_string *instead_of;
34         int instead_of_nr;
35         int instead_of_alloc;
36 };
37 struct rewrites {
38         struct rewrite **rewrite;
39         int rewrite_alloc;
40         int rewrite_nr;
41 };
42
43 static struct remote **remotes;
44 static int remotes_alloc;
45 static int remotes_nr;
46 static struct hashmap remotes_hash;
47
48 static struct branch **branches;
49 static int branches_alloc;
50 static int branches_nr;
51
52 static struct branch *current_branch;
53 static const char *pushremote_name;
54
55 static struct rewrites rewrites;
56 static struct rewrites rewrites_push;
57
58 static int valid_remote(const struct remote *remote)
59 {
60         return (!!remote->url) || (!!remote->foreign_vcs);
61 }
62
63 static const char *alias_url(const char *url, struct rewrites *r)
64 {
65         int i, j;
66         struct counted_string *longest;
67         int longest_i;
68
69         longest = NULL;
70         longest_i = -1;
71         for (i = 0; i < r->rewrite_nr; i++) {
72                 if (!r->rewrite[i])
73                         continue;
74                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
75                         if (starts_with(url, r->rewrite[i]->instead_of[j].s) &&
76                             (!longest ||
77                              longest->len < r->rewrite[i]->instead_of[j].len)) {
78                                 longest = &(r->rewrite[i]->instead_of[j]);
79                                 longest_i = i;
80                         }
81                 }
82         }
83         if (!longest)
84                 return url;
85
86         return xstrfmt("%s%s", r->rewrite[longest_i]->base, url + longest->len);
87 }
88
89 static void add_push_refspec(struct remote *remote, const char *ref)
90 {
91         ALLOC_GROW(remote->push_refspec,
92                    remote->push_refspec_nr + 1,
93                    remote->push_refspec_alloc);
94         remote->push_refspec[remote->push_refspec_nr++] = ref;
95 }
96
97 static void add_fetch_refspec(struct remote *remote, const char *ref)
98 {
99         ALLOC_GROW(remote->fetch_refspec,
100                    remote->fetch_refspec_nr + 1,
101                    remote->fetch_refspec_alloc);
102         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
103 }
104
105 static void add_url(struct remote *remote, const char *url)
106 {
107         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
108         remote->url[remote->url_nr++] = url;
109 }
110
111 static void add_pushurl(struct remote *remote, const char *pushurl)
112 {
113         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
114         remote->pushurl[remote->pushurl_nr++] = pushurl;
115 }
116
117 static void add_pushurl_alias(struct remote *remote, const char *url)
118 {
119         const char *pushurl = alias_url(url, &rewrites_push);
120         if (pushurl != url)
121                 add_pushurl(remote, pushurl);
122 }
123
124 static void add_url_alias(struct remote *remote, const char *url)
125 {
126         add_url(remote, alias_url(url, &rewrites));
127         add_pushurl_alias(remote, url);
128 }
129
130 struct remotes_hash_key {
131         const char *str;
132         int len;
133 };
134
135 static int remotes_hash_cmp(const struct remote *a, const struct remote *b, const struct remotes_hash_key *key)
136 {
137         if (key)
138                 return strncmp(a->name, key->str, key->len) || a->name[key->len];
139         else
140                 return strcmp(a->name, b->name);
141 }
142
143 static inline void init_remotes_hash(void)
144 {
145         if (!remotes_hash.cmpfn)
146                 hashmap_init(&remotes_hash, (hashmap_cmp_fn)remotes_hash_cmp, 0);
147 }
148
149 static struct remote *make_remote(const char *name, int len)
150 {
151         struct remote *ret, *replaced;
152         struct remotes_hash_key lookup;
153         struct hashmap_entry lookup_entry;
154
155         if (!len)
156                 len = strlen(name);
157
158         init_remotes_hash();
159         lookup.str = name;
160         lookup.len = len;
161         hashmap_entry_init(&lookup_entry, memhash(name, len));
162
163         if ((ret = hashmap_get(&remotes_hash, &lookup_entry, &lookup)) != NULL)
164                 return ret;
165
166         ret = xcalloc(1, sizeof(struct remote));
167         ret->prune = -1;  /* unspecified */
168         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
169         remotes[remotes_nr++] = ret;
170         ret->name = xstrndup(name, len);
171
172         hashmap_entry_init(ret, lookup_entry.hash);
173         replaced = hashmap_put(&remotes_hash, ret);
174         assert(replaced == NULL);  /* no previous entry overwritten */
175         return ret;
176 }
177
178 static void add_merge(struct branch *branch, const char *name)
179 {
180         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
181                    branch->merge_alloc);
182         branch->merge_name[branch->merge_nr++] = name;
183 }
184
185 static struct branch *make_branch(const char *name, int len)
186 {
187         struct branch *ret;
188         int i;
189
190         for (i = 0; i < branches_nr; i++) {
191                 if (len ? (!strncmp(name, branches[i]->name, len) &&
192                            !branches[i]->name[len]) :
193                     !strcmp(name, branches[i]->name))
194                         return branches[i];
195         }
196
197         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
198         ret = xcalloc(1, sizeof(struct branch));
199         branches[branches_nr++] = ret;
200         if (len)
201                 ret->name = xstrndup(name, len);
202         else
203                 ret->name = xstrdup(name);
204         ret->refname = xstrfmt("refs/heads/%s", ret->name);
205
206         return ret;
207 }
208
209 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
210 {
211         struct rewrite *ret;
212         int i;
213
214         for (i = 0; i < r->rewrite_nr; i++) {
215                 if (len
216                     ? (len == r->rewrite[i]->baselen &&
217                        !strncmp(base, r->rewrite[i]->base, len))
218                     : !strcmp(base, r->rewrite[i]->base))
219                         return r->rewrite[i];
220         }
221
222         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
223         ret = xcalloc(1, sizeof(struct rewrite));
224         r->rewrite[r->rewrite_nr++] = ret;
225         if (len) {
226                 ret->base = xstrndup(base, len);
227                 ret->baselen = len;
228         }
229         else {
230                 ret->base = xstrdup(base);
231                 ret->baselen = strlen(base);
232         }
233         return ret;
234 }
235
236 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
237 {
238         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
239         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
240         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
241         rewrite->instead_of_nr++;
242 }
243
244 static const char *skip_spaces(const char *s)
245 {
246         while (isspace(*s))
247                 s++;
248         return s;
249 }
250
251 static void read_remotes_file(struct remote *remote)
252 {
253         struct strbuf buf = STRBUF_INIT;
254         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
255
256         if (!f)
257                 return;
258         remote->configured_in_repo = 1;
259         remote->origin = REMOTE_REMOTES;
260         while (strbuf_getline(&buf, f) != EOF) {
261                 const char *v;
262
263                 strbuf_rtrim(&buf);
264
265                 if (skip_prefix(buf.buf, "URL:", &v))
266                         add_url_alias(remote, xstrdup(skip_spaces(v)));
267                 else if (skip_prefix(buf.buf, "Push:", &v))
268                         add_push_refspec(remote, xstrdup(skip_spaces(v)));
269                 else if (skip_prefix(buf.buf, "Pull:", &v))
270                         add_fetch_refspec(remote, xstrdup(skip_spaces(v)));
271         }
272         strbuf_release(&buf);
273         fclose(f);
274 }
275
276 static void read_branches_file(struct remote *remote)
277 {
278         char *frag;
279         struct strbuf buf = STRBUF_INIT;
280         FILE *f = fopen(git_path("branches/%s", remote->name), "r");
281
282         if (!f)
283                 return;
284
285         strbuf_getline_lf(&buf, f);
286         fclose(f);
287         strbuf_trim(&buf);
288         if (!buf.len) {
289                 strbuf_release(&buf);
290                 return;
291         }
292
293         remote->configured_in_repo = 1;
294         remote->origin = REMOTE_BRANCHES;
295
296         /*
297          * The branches file would have URL and optionally
298          * #branch specified.  The "master" (or specified) branch is
299          * fetched and stored in the local branch matching the
300          * remote name.
301          */
302         frag = strchr(buf.buf, '#');
303         if (frag)
304                 *(frag++) = '\0';
305         else
306                 frag = "master";
307
308         add_url_alias(remote, strbuf_detach(&buf, NULL));
309         add_fetch_refspec(remote, xstrfmt("refs/heads/%s:refs/heads/%s",
310                                           frag, remote->name));
311
312         /*
313          * Cogito compatible push: push current HEAD to remote #branch
314          * (master if missing)
315          */
316         add_push_refspec(remote, xstrfmt("HEAD:refs/heads/%s", frag));
317         remote->fetch_tags = 1; /* always auto-follow */
318 }
319
320 static int handle_config(const char *key, const char *value, void *cb)
321 {
322         const char *name;
323         int namelen;
324         const char *subkey;
325         struct remote *remote;
326         struct branch *branch;
327         if (parse_config_key(key, "branch", &name, &namelen, &subkey) >= 0) {
328                 if (!name)
329                         return 0;
330                 branch = make_branch(name, namelen);
331                 if (!strcmp(subkey, "remote")) {
332                         return git_config_string(&branch->remote_name, key, value);
333                 } else if (!strcmp(subkey, "pushremote")) {
334                         return git_config_string(&branch->pushremote_name, key, value);
335                 } else if (!strcmp(subkey, "merge")) {
336                         if (!value)
337                                 return config_error_nonbool(key);
338                         add_merge(branch, xstrdup(value));
339                 }
340                 return 0;
341         }
342         if (parse_config_key(key, "url", &name, &namelen, &subkey) >= 0) {
343                 struct rewrite *rewrite;
344                 if (!name)
345                         return 0;
346                 if (!strcmp(subkey, "insteadof")) {
347                         rewrite = make_rewrite(&rewrites, name, namelen);
348                         if (!value)
349                                 return config_error_nonbool(key);
350                         add_instead_of(rewrite, xstrdup(value));
351                 } else if (!strcmp(subkey, "pushinsteadof")) {
352                         rewrite = make_rewrite(&rewrites_push, name, namelen);
353                         if (!value)
354                                 return config_error_nonbool(key);
355                         add_instead_of(rewrite, xstrdup(value));
356                 }
357         }
358
359         if (parse_config_key(key, "remote", &name, &namelen, &subkey) < 0)
360                 return 0;
361
362         /* Handle remote.* variables */
363         if (!name && !strcmp(subkey, "pushdefault"))
364                 return git_config_string(&pushremote_name, key, value);
365
366         if (!name)
367                 return 0;
368         /* Handle remote.<name>.* variables */
369         if (*name == '/') {
370                 warning("Config remote shorthand cannot begin with '/': %s",
371                         name);
372                 return 0;
373         }
374         remote = make_remote(name, namelen);
375         remote->origin = REMOTE_CONFIG;
376         if (current_config_scope() == CONFIG_SCOPE_REPO)
377                 remote->configured_in_repo = 1;
378         if (!strcmp(subkey, "mirror"))
379                 remote->mirror = git_config_bool(key, value);
380         else if (!strcmp(subkey, "skipdefaultupdate"))
381                 remote->skip_default_update = git_config_bool(key, value);
382         else if (!strcmp(subkey, "skipfetchall"))
383                 remote->skip_default_update = git_config_bool(key, value);
384         else if (!strcmp(subkey, "prune"))
385                 remote->prune = git_config_bool(key, value);
386         else if (!strcmp(subkey, "url")) {
387                 const char *v;
388                 if (git_config_string(&v, key, value))
389                         return -1;
390                 add_url(remote, v);
391         } else if (!strcmp(subkey, "pushurl")) {
392                 const char *v;
393                 if (git_config_string(&v, key, value))
394                         return -1;
395                 add_pushurl(remote, v);
396         } else if (!strcmp(subkey, "push")) {
397                 const char *v;
398                 if (git_config_string(&v, key, value))
399                         return -1;
400                 add_push_refspec(remote, v);
401         } else if (!strcmp(subkey, "fetch")) {
402                 const char *v;
403                 if (git_config_string(&v, key, value))
404                         return -1;
405                 add_fetch_refspec(remote, v);
406         } else if (!strcmp(subkey, "receivepack")) {
407                 const char *v;
408                 if (git_config_string(&v, key, value))
409                         return -1;
410                 if (!remote->receivepack)
411                         remote->receivepack = v;
412                 else
413                         error("more than one receivepack given, using the first");
414         } else if (!strcmp(subkey, "uploadpack")) {
415                 const char *v;
416                 if (git_config_string(&v, key, value))
417                         return -1;
418                 if (!remote->uploadpack)
419                         remote->uploadpack = v;
420                 else
421                         error("more than one uploadpack given, using the first");
422         } else if (!strcmp(subkey, "tagopt")) {
423                 if (!strcmp(value, "--no-tags"))
424                         remote->fetch_tags = -1;
425                 else if (!strcmp(value, "--tags"))
426                         remote->fetch_tags = 2;
427         } else if (!strcmp(subkey, "proxy")) {
428                 return git_config_string((const char **)&remote->http_proxy,
429                                          key, value);
430         } else if (!strcmp(subkey, "proxyauthmethod")) {
431                 return git_config_string((const char **)&remote->http_proxy_authmethod,
432                                          key, value);
433         } else if (!strcmp(subkey, "vcs")) {
434                 return git_config_string(&remote->foreign_vcs, key, value);
435         }
436         return 0;
437 }
438
439 static void alias_all_urls(void)
440 {
441         int i, j;
442         for (i = 0; i < remotes_nr; i++) {
443                 int add_pushurl_aliases;
444                 if (!remotes[i])
445                         continue;
446                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
447                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
448                 }
449                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
450                 for (j = 0; j < remotes[i]->url_nr; j++) {
451                         if (add_pushurl_aliases)
452                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
453                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
454                 }
455         }
456 }
457
458 static void read_config(void)
459 {
460         static int loaded;
461         struct object_id oid;
462         int flag;
463
464         if (loaded)
465                 return;
466         loaded = 1;
467
468         current_branch = NULL;
469         if (startup_info->have_repository) {
470                 const char *head_ref = resolve_ref_unsafe("HEAD", 0, oid.hash, &flag);
471                 if (head_ref && (flag & REF_ISSYMREF) &&
472                     skip_prefix(head_ref, "refs/heads/", &head_ref)) {
473                         current_branch = make_branch(head_ref, 0);
474                 }
475         }
476         git_config(handle_config, NULL);
477         alias_all_urls();
478 }
479
480 /*
481  * This function frees a refspec array.
482  * Warning: code paths should be checked to ensure that the src
483  *          and dst pointers are always freeable pointers as well
484  *          as the refspec pointer itself.
485  */
486 static void free_refspecs(struct refspec *refspec, int nr_refspec)
487 {
488         int i;
489
490         if (!refspec)
491                 return;
492
493         for (i = 0; i < nr_refspec; i++) {
494                 free(refspec[i].src);
495                 free(refspec[i].dst);
496         }
497         free(refspec);
498 }
499
500 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
501 {
502         int i;
503         struct refspec *rs = xcalloc(nr_refspec, sizeof(*rs));
504
505         for (i = 0; i < nr_refspec; i++) {
506                 size_t llen;
507                 int is_glob;
508                 const char *lhs, *rhs;
509                 int flags;
510
511                 is_glob = 0;
512
513                 lhs = refspec[i];
514                 if (*lhs == '+') {
515                         rs[i].force = 1;
516                         lhs++;
517                 }
518
519                 rhs = strrchr(lhs, ':');
520
521                 /*
522                  * Before going on, special case ":" (or "+:") as a refspec
523                  * for pushing matching refs.
524                  */
525                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
526                         rs[i].matching = 1;
527                         continue;
528                 }
529
530                 if (rhs) {
531                         size_t rlen = strlen(++rhs);
532                         is_glob = (1 <= rlen && strchr(rhs, '*'));
533                         rs[i].dst = xstrndup(rhs, rlen);
534                 }
535
536                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
537                 if (1 <= llen && memchr(lhs, '*', llen)) {
538                         if ((rhs && !is_glob) || (!rhs && fetch))
539                                 goto invalid;
540                         is_glob = 1;
541                 } else if (rhs && is_glob) {
542                         goto invalid;
543                 }
544
545                 rs[i].pattern = is_glob;
546                 rs[i].src = xstrndup(lhs, llen);
547                 flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
548
549                 if (fetch) {
550                         struct object_id unused;
551
552                         /* LHS */
553                         if (!*rs[i].src)
554                                 ; /* empty is ok; it means "HEAD" */
555                         else if (llen == GIT_SHA1_HEXSZ && !get_oid_hex(rs[i].src, &unused))
556                                 rs[i].exact_sha1 = 1; /* ok */
557                         else if (!check_refname_format(rs[i].src, flags))
558                                 ; /* valid looking ref is ok */
559                         else
560                                 goto invalid;
561                         /* RHS */
562                         if (!rs[i].dst)
563                                 ; /* missing is ok; it is the same as empty */
564                         else if (!*rs[i].dst)
565                                 ; /* empty is ok; it means "do not store" */
566                         else if (!check_refname_format(rs[i].dst, flags))
567                                 ; /* valid looking ref is ok */
568                         else
569                                 goto invalid;
570                 } else {
571                         /*
572                          * LHS
573                          * - empty is allowed; it means delete.
574                          * - when wildcarded, it must be a valid looking ref.
575                          * - otherwise, it must be an extended SHA-1, but
576                          *   there is no existing way to validate this.
577                          */
578                         if (!*rs[i].src)
579                                 ; /* empty is ok */
580                         else if (is_glob) {
581                                 if (check_refname_format(rs[i].src, flags))
582                                         goto invalid;
583                         }
584                         else
585                                 ; /* anything goes, for now */
586                         /*
587                          * RHS
588                          * - missing is allowed, but LHS then must be a
589                          *   valid looking ref.
590                          * - empty is not allowed.
591                          * - otherwise it must be a valid looking ref.
592                          */
593                         if (!rs[i].dst) {
594                                 if (check_refname_format(rs[i].src, flags))
595                                         goto invalid;
596                         } else if (!*rs[i].dst) {
597                                 goto invalid;
598                         } else {
599                                 if (check_refname_format(rs[i].dst, flags))
600                                         goto invalid;
601                         }
602                 }
603         }
604         return rs;
605
606  invalid:
607         if (verify) {
608                 /*
609                  * nr_refspec must be greater than zero and i must be valid
610                  * since it is only possible to reach this point from within
611                  * the for loop above.
612                  */
613                 free_refspecs(rs, i+1);
614                 return NULL;
615         }
616         die("Invalid refspec '%s'", refspec[i]);
617 }
618
619 int valid_fetch_refspec(const char *fetch_refspec_str)
620 {
621         struct refspec *refspec;
622
623         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
624         free_refspecs(refspec, 1);
625         return !!refspec;
626 }
627
628 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
629 {
630         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
631 }
632
633 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
634 {
635         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
636 }
637
638 void free_refspec(int nr_refspec, struct refspec *refspec)
639 {
640         int i;
641         for (i = 0; i < nr_refspec; i++) {
642                 free(refspec[i].src);
643                 free(refspec[i].dst);
644         }
645         free(refspec);
646 }
647
648 static int valid_remote_nick(const char *name)
649 {
650         if (!name[0] || is_dot_or_dotdot(name))
651                 return 0;
652         return !strchr(name, '/'); /* no slash */
653 }
654
655 const char *remote_for_branch(struct branch *branch, int *explicit)
656 {
657         if (branch && branch->remote_name) {
658                 if (explicit)
659                         *explicit = 1;
660                 return branch->remote_name;
661         }
662         if (explicit)
663                 *explicit = 0;
664         return "origin";
665 }
666
667 const char *pushremote_for_branch(struct branch *branch, int *explicit)
668 {
669         if (branch && branch->pushremote_name) {
670                 if (explicit)
671                         *explicit = 1;
672                 return branch->pushremote_name;
673         }
674         if (pushremote_name) {
675                 if (explicit)
676                         *explicit = 1;
677                 return pushremote_name;
678         }
679         return remote_for_branch(branch, explicit);
680 }
681
682 static struct remote *remote_get_1(const char *name,
683                                    const char *(*get_default)(struct branch *, int *))
684 {
685         struct remote *ret;
686         int name_given = 0;
687
688         read_config();
689
690         if (name)
691                 name_given = 1;
692         else
693                 name = get_default(current_branch, &name_given);
694
695         ret = make_remote(name, 0);
696         if (valid_remote_nick(name) && have_git_dir()) {
697                 if (!valid_remote(ret))
698                         read_remotes_file(ret);
699                 if (!valid_remote(ret))
700                         read_branches_file(ret);
701         }
702         if (name_given && !valid_remote(ret))
703                 add_url_alias(ret, name);
704         if (!valid_remote(ret))
705                 return NULL;
706         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
707         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
708         return ret;
709 }
710
711 struct remote *remote_get(const char *name)
712 {
713         return remote_get_1(name, remote_for_branch);
714 }
715
716 struct remote *pushremote_get(const char *name)
717 {
718         return remote_get_1(name, pushremote_for_branch);
719 }
720
721 int remote_is_configured(struct remote *remote, int in_repo)
722 {
723         if (!remote)
724                 return 0;
725         if (in_repo)
726                 return remote->configured_in_repo;
727         return !!remote->origin;
728 }
729
730 int for_each_remote(each_remote_fn fn, void *priv)
731 {
732         int i, result = 0;
733         read_config();
734         for (i = 0; i < remotes_nr && !result; i++) {
735                 struct remote *r = remotes[i];
736                 if (!r)
737                         continue;
738                 if (!r->fetch)
739                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
740                                                        r->fetch_refspec);
741                 if (!r->push)
742                         r->push = parse_push_refspec(r->push_refspec_nr,
743                                                      r->push_refspec);
744                 result = fn(r, priv);
745         }
746         return result;
747 }
748
749 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
750 {
751         if (strcmp(ref1->name, ref2->name)) {
752                 if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
753                     ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
754                         die(_("Cannot fetch both %s and %s to %s"),
755                             ref1->name, ref2->name, ref2->peer_ref->name);
756                 } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
757                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
758                         warning(_("%s usually tracks %s, not %s"),
759                                 ref2->peer_ref->name, ref2->name, ref1->name);
760                 } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
761                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
762                         die(_("%s tracks both %s and %s"),
763                             ref2->peer_ref->name, ref1->name, ref2->name);
764                 } else {
765                         /*
766                          * This last possibility doesn't occur because
767                          * FETCH_HEAD_IGNORE entries always appear at
768                          * the end of the list.
769                          */
770                         die(_("Internal error"));
771                 }
772         }
773         free(ref2->peer_ref);
774         free(ref2);
775 }
776
777 struct ref *ref_remove_duplicates(struct ref *ref_map)
778 {
779         struct string_list refs = STRING_LIST_INIT_NODUP;
780         struct ref *retval = NULL;
781         struct ref **p = &retval;
782
783         while (ref_map) {
784                 struct ref *ref = ref_map;
785
786                 ref_map = ref_map->next;
787                 ref->next = NULL;
788
789                 if (!ref->peer_ref) {
790                         *p = ref;
791                         p = &ref->next;
792                 } else {
793                         struct string_list_item *item =
794                                 string_list_insert(&refs, ref->peer_ref->name);
795
796                         if (item->util) {
797                                 /* Entry already existed */
798                                 handle_duplicate((struct ref *)item->util, ref);
799                         } else {
800                                 *p = ref;
801                                 p = &ref->next;
802                                 item->util = ref;
803                         }
804                 }
805         }
806
807         string_list_clear(&refs, 0);
808         return retval;
809 }
810
811 int remote_has_url(struct remote *remote, const char *url)
812 {
813         int i;
814         for (i = 0; i < remote->url_nr; i++) {
815                 if (!strcmp(remote->url[i], url))
816                         return 1;
817         }
818         return 0;
819 }
820
821 static int match_name_with_pattern(const char *key, const char *name,
822                                    const char *value, char **result)
823 {
824         const char *kstar = strchr(key, '*');
825         size_t klen;
826         size_t ksuffixlen;
827         size_t namelen;
828         int ret;
829         if (!kstar)
830                 die("Key '%s' of pattern had no '*'", key);
831         klen = kstar - key;
832         ksuffixlen = strlen(kstar + 1);
833         namelen = strlen(name);
834         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
835                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
836         if (ret && value) {
837                 struct strbuf sb = STRBUF_INIT;
838                 const char *vstar = strchr(value, '*');
839                 if (!vstar)
840                         die("Value '%s' of pattern has no '*'", value);
841                 strbuf_add(&sb, value, vstar - value);
842                 strbuf_add(&sb, name + klen, namelen - klen - ksuffixlen);
843                 strbuf_addstr(&sb, vstar + 1);
844                 *result = strbuf_detach(&sb, NULL);
845         }
846         return ret;
847 }
848
849 static void query_refspecs_multiple(struct refspec *refs, int ref_count, struct refspec *query, struct string_list *results)
850 {
851         int i;
852         int find_src = !query->src;
853
854         if (find_src && !query->dst)
855                 error("query_refspecs_multiple: need either src or dst");
856
857         for (i = 0; i < ref_count; i++) {
858                 struct refspec *refspec = &refs[i];
859                 const char *key = find_src ? refspec->dst : refspec->src;
860                 const char *value = find_src ? refspec->src : refspec->dst;
861                 const char *needle = find_src ? query->dst : query->src;
862                 char **result = find_src ? &query->src : &query->dst;
863
864                 if (!refspec->dst)
865                         continue;
866                 if (refspec->pattern) {
867                         if (match_name_with_pattern(key, needle, value, result))
868                                 string_list_append_nodup(results, *result);
869                 } else if (!strcmp(needle, key)) {
870                         string_list_append(results, value);
871                 }
872         }
873 }
874
875 int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
876 {
877         int i;
878         int find_src = !query->src;
879         const char *needle = find_src ? query->dst : query->src;
880         char **result = find_src ? &query->src : &query->dst;
881
882         if (find_src && !query->dst)
883                 return error("query_refspecs: need either src or dst");
884
885         for (i = 0; i < ref_count; i++) {
886                 struct refspec *refspec = &refs[i];
887                 const char *key = find_src ? refspec->dst : refspec->src;
888                 const char *value = find_src ? refspec->src : refspec->dst;
889
890                 if (!refspec->dst)
891                         continue;
892                 if (refspec->pattern) {
893                         if (match_name_with_pattern(key, needle, value, result)) {
894                                 query->force = refspec->force;
895                                 return 0;
896                         }
897                 } else if (!strcmp(needle, key)) {
898                         *result = xstrdup(value);
899                         query->force = refspec->force;
900                         return 0;
901                 }
902         }
903         return -1;
904 }
905
906 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
907                      const char *name)
908 {
909         struct refspec query;
910
911         memset(&query, 0, sizeof(struct refspec));
912         query.src = (char *)name;
913
914         if (query_refspecs(refspecs, nr_refspec, &query))
915                 return NULL;
916
917         return query.dst;
918 }
919
920 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
921 {
922         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
923 }
924
925 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
926                 const char *name)
927 {
928         size_t len = strlen(name);
929         struct ref *ref = xcalloc(1, st_add4(sizeof(*ref), prefixlen, len, 1));
930         memcpy(ref->name, prefix, prefixlen);
931         memcpy(ref->name + prefixlen, name, len);
932         return ref;
933 }
934
935 struct ref *alloc_ref(const char *name)
936 {
937         return alloc_ref_with_prefix("", 0, name);
938 }
939
940 struct ref *copy_ref(const struct ref *ref)
941 {
942         struct ref *cpy;
943         size_t len;
944         if (!ref)
945                 return NULL;
946         len = st_add3(sizeof(struct ref), strlen(ref->name), 1);
947         cpy = xmalloc(len);
948         memcpy(cpy, ref, len);
949         cpy->next = NULL;
950         cpy->symref = xstrdup_or_null(ref->symref);
951         cpy->remote_status = xstrdup_or_null(ref->remote_status);
952         cpy->peer_ref = copy_ref(ref->peer_ref);
953         return cpy;
954 }
955
956 struct ref *copy_ref_list(const struct ref *ref)
957 {
958         struct ref *ret = NULL;
959         struct ref **tail = &ret;
960         while (ref) {
961                 *tail = copy_ref(ref);
962                 ref = ref->next;
963                 tail = &((*tail)->next);
964         }
965         return ret;
966 }
967
968 static void free_ref(struct ref *ref)
969 {
970         if (!ref)
971                 return;
972         free_ref(ref->peer_ref);
973         free(ref->remote_status);
974         free(ref->symref);
975         free(ref);
976 }
977
978 void free_refs(struct ref *ref)
979 {
980         struct ref *next;
981         while (ref) {
982                 next = ref->next;
983                 free_ref(ref);
984                 ref = next;
985         }
986 }
987
988 int ref_compare_name(const void *va, const void *vb)
989 {
990         const struct ref *a = va, *b = vb;
991         return strcmp(a->name, b->name);
992 }
993
994 static void *ref_list_get_next(const void *a)
995 {
996         return ((const struct ref *)a)->next;
997 }
998
999 static void ref_list_set_next(void *a, void *next)
1000 {
1001         ((struct ref *)a)->next = next;
1002 }
1003
1004 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
1005 {
1006         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
1007 }
1008
1009 int count_refspec_match(const char *pattern,
1010                         struct ref *refs,
1011                         struct ref **matched_ref)
1012 {
1013         int patlen = strlen(pattern);
1014         struct ref *matched_weak = NULL;
1015         struct ref *matched = NULL;
1016         int weak_match = 0;
1017         int match = 0;
1018
1019         for (weak_match = match = 0; refs; refs = refs->next) {
1020                 char *name = refs->name;
1021                 int namelen = strlen(name);
1022
1023                 if (!refname_match(pattern, name))
1024                         continue;
1025
1026                 /* A match is "weak" if it is with refs outside
1027                  * heads or tags, and did not specify the pattern
1028                  * in full (e.g. "refs/remotes/origin/master") or at
1029                  * least from the toplevel (e.g. "remotes/origin/master");
1030                  * otherwise "git push $URL master" would result in
1031                  * ambiguity between remotes/origin/master and heads/master
1032                  * at the remote site.
1033                  */
1034                 if (namelen != patlen &&
1035                     patlen != namelen - 5 &&
1036                     !starts_with(name, "refs/heads/") &&
1037                     !starts_with(name, "refs/tags/")) {
1038                         /* We want to catch the case where only weak
1039                          * matches are found and there are multiple
1040                          * matches, and where more than one strong
1041                          * matches are found, as ambiguous.  One
1042                          * strong match with zero or more weak matches
1043                          * are acceptable as a unique match.
1044                          */
1045                         matched_weak = refs;
1046                         weak_match++;
1047                 }
1048                 else {
1049                         matched = refs;
1050                         match++;
1051                 }
1052         }
1053         if (!matched) {
1054                 if (matched_ref)
1055                         *matched_ref = matched_weak;
1056                 return weak_match;
1057         }
1058         else {
1059                 if (matched_ref)
1060                         *matched_ref = matched;
1061                 return match;
1062         }
1063 }
1064
1065 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1066 {
1067         **tail = ref;
1068         while (ref->next)
1069                 ref = ref->next;
1070         *tail = &ref->next;
1071 }
1072
1073 static struct ref *alloc_delete_ref(void)
1074 {
1075         struct ref *ref = alloc_ref("(delete)");
1076         oidclr(&ref->new_oid);
1077         return ref;
1078 }
1079
1080 static int try_explicit_object_name(const char *name,
1081                                     struct ref **match)
1082 {
1083         struct object_id oid;
1084
1085         if (!*name) {
1086                 if (match)
1087                         *match = alloc_delete_ref();
1088                 return 0;
1089         }
1090
1091         if (get_sha1(name, oid.hash))
1092                 return -1;
1093
1094         if (match) {
1095                 *match = alloc_ref(name);
1096                 oidcpy(&(*match)->new_oid, &oid);
1097         }
1098         return 0;
1099 }
1100
1101 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1102 {
1103         struct ref *ret = alloc_ref(name);
1104         tail_link_ref(ret, tail);
1105         return ret;
1106 }
1107
1108 static char *guess_ref(const char *name, struct ref *peer)
1109 {
1110         struct strbuf buf = STRBUF_INIT;
1111         struct object_id oid;
1112
1113         const char *r = resolve_ref_unsafe(peer->name, RESOLVE_REF_READING,
1114                                            oid.hash, NULL);
1115         if (!r)
1116                 return NULL;
1117
1118         if (starts_with(r, "refs/heads/"))
1119                 strbuf_addstr(&buf, "refs/heads/");
1120         else if (starts_with(r, "refs/tags/"))
1121                 strbuf_addstr(&buf, "refs/tags/");
1122         else
1123                 return NULL;
1124
1125         strbuf_addstr(&buf, name);
1126         return strbuf_detach(&buf, NULL);
1127 }
1128
1129 static int match_explicit_lhs(struct ref *src,
1130                               struct refspec *rs,
1131                               struct ref **match,
1132                               int *allocated_match)
1133 {
1134         switch (count_refspec_match(rs->src, src, match)) {
1135         case 1:
1136                 if (allocated_match)
1137                         *allocated_match = 0;
1138                 return 0;
1139         case 0:
1140                 /* The source could be in the get_sha1() format
1141                  * not a reference name.  :refs/other is a
1142                  * way to delete 'other' ref at the remote end.
1143                  */
1144                 if (try_explicit_object_name(rs->src, match) < 0)
1145                         return error("src refspec %s does not match any.", rs->src);
1146                 if (allocated_match)
1147                         *allocated_match = 1;
1148                 return 0;
1149         default:
1150                 return error("src refspec %s matches more than one.", rs->src);
1151         }
1152 }
1153
1154 static int match_explicit(struct ref *src, struct ref *dst,
1155                           struct ref ***dst_tail,
1156                           struct refspec *rs)
1157 {
1158         struct ref *matched_src, *matched_dst;
1159         int allocated_src;
1160
1161         const char *dst_value = rs->dst;
1162         char *dst_guess;
1163
1164         if (rs->pattern || rs->matching)
1165                 return 0;
1166
1167         matched_src = matched_dst = NULL;
1168         if (match_explicit_lhs(src, rs, &matched_src, &allocated_src) < 0)
1169                 return -1;
1170
1171         if (!dst_value) {
1172                 struct object_id oid;
1173                 int flag;
1174
1175                 dst_value = resolve_ref_unsafe(matched_src->name,
1176                                                RESOLVE_REF_READING,
1177                                                oid.hash, &flag);
1178                 if (!dst_value ||
1179                     ((flag & REF_ISSYMREF) &&
1180                      !starts_with(dst_value, "refs/heads/")))
1181                         die("%s cannot be resolved to branch.",
1182                             matched_src->name);
1183         }
1184
1185         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1186         case 1:
1187                 break;
1188         case 0:
1189                 if (starts_with(dst_value, "refs/"))
1190                         matched_dst = make_linked_ref(dst_value, dst_tail);
1191                 else if (is_null_oid(&matched_src->new_oid))
1192                         error("unable to delete '%s': remote ref does not exist",
1193                               dst_value);
1194                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1195                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1196                 else
1197                         error("unable to push to unqualified destination: %s\n"
1198                               "The destination refspec neither matches an "
1199                               "existing ref on the remote nor\n"
1200                               "begins with refs/, and we are unable to "
1201                               "guess a prefix based on the source ref.",
1202                               dst_value);
1203                 break;
1204         default:
1205                 matched_dst = NULL;
1206                 error("dst refspec %s matches more than one.",
1207                       dst_value);
1208                 break;
1209         }
1210         if (!matched_dst)
1211                 return -1;
1212         if (matched_dst->peer_ref)
1213                 return error("dst ref %s receives from more than one src.",
1214                       matched_dst->name);
1215         else {
1216                 matched_dst->peer_ref = allocated_src ?
1217                                         matched_src :
1218                                         copy_ref(matched_src);
1219                 matched_dst->force = rs->force;
1220         }
1221         return 0;
1222 }
1223
1224 static int match_explicit_refs(struct ref *src, struct ref *dst,
1225                                struct ref ***dst_tail, struct refspec *rs,
1226                                int rs_nr)
1227 {
1228         int i, errs;
1229         for (i = errs = 0; i < rs_nr; i++)
1230                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1231         return errs;
1232 }
1233
1234 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1235                 int send_mirror, int direction, const struct refspec **ret_pat)
1236 {
1237         const struct refspec *pat;
1238         char *name;
1239         int i;
1240         int matching_refs = -1;
1241         for (i = 0; i < rs_nr; i++) {
1242                 if (rs[i].matching &&
1243                     (matching_refs == -1 || rs[i].force)) {
1244                         matching_refs = i;
1245                         continue;
1246                 }
1247
1248                 if (rs[i].pattern) {
1249                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1250                         int match;
1251                         if (direction == FROM_SRC)
1252                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1253                         else
1254                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1255                         if (match) {
1256                                 matching_refs = i;
1257                                 break;
1258                         }
1259                 }
1260         }
1261         if (matching_refs == -1)
1262                 return NULL;
1263
1264         pat = rs + matching_refs;
1265         if (pat->matching) {
1266                 /*
1267                  * "matching refs"; traditionally we pushed everything
1268                  * including refs outside refs/heads/ hierarchy, but
1269                  * that does not make much sense these days.
1270                  */
1271                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1272                         return NULL;
1273                 name = xstrdup(ref->name);
1274         }
1275         if (ret_pat)
1276                 *ret_pat = pat;
1277         return name;
1278 }
1279
1280 static struct ref **tail_ref(struct ref **head)
1281 {
1282         struct ref **tail = head;
1283         while (*tail)
1284                 tail = &((*tail)->next);
1285         return tail;
1286 }
1287
1288 struct tips {
1289         struct commit **tip;
1290         int nr, alloc;
1291 };
1292
1293 static void add_to_tips(struct tips *tips, const struct object_id *oid)
1294 {
1295         struct commit *commit;
1296
1297         if (is_null_oid(oid))
1298                 return;
1299         commit = lookup_commit_reference_gently(oid->hash, 1);
1300         if (!commit || (commit->object.flags & TMP_MARK))
1301                 return;
1302         commit->object.flags |= TMP_MARK;
1303         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1304         tips->tip[tips->nr++] = commit;
1305 }
1306
1307 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1308 {
1309         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1310         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1311         struct string_list_item *item;
1312         struct ref *ref;
1313         struct tips sent_tips;
1314
1315         /*
1316          * Collect everything we know they would have at the end of
1317          * this push, and collect all tags they have.
1318          */
1319         memset(&sent_tips, 0, sizeof(sent_tips));
1320         for (ref = *dst; ref; ref = ref->next) {
1321                 if (ref->peer_ref &&
1322                     !is_null_oid(&ref->peer_ref->new_oid))
1323                         add_to_tips(&sent_tips, &ref->peer_ref->new_oid);
1324                 else
1325                         add_to_tips(&sent_tips, &ref->old_oid);
1326                 if (starts_with(ref->name, "refs/tags/"))
1327                         string_list_append(&dst_tag, ref->name);
1328         }
1329         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1330
1331         string_list_sort(&dst_tag);
1332
1333         /* Collect tags they do not have. */
1334         for (ref = src; ref; ref = ref->next) {
1335                 if (!starts_with(ref->name, "refs/tags/"))
1336                         continue; /* not a tag */
1337                 if (string_list_has_string(&dst_tag, ref->name))
1338                         continue; /* they already have it */
1339                 if (sha1_object_info(ref->new_oid.hash, NULL) != OBJ_TAG)
1340                         continue; /* be conservative */
1341                 item = string_list_append(&src_tag, ref->name);
1342                 item->util = ref;
1343         }
1344         string_list_clear(&dst_tag, 0);
1345
1346         /*
1347          * At this point, src_tag lists tags that are missing from
1348          * dst, and sent_tips lists the tips we are pushing or those
1349          * that we know they already have. An element in the src_tag
1350          * that is an ancestor of any of the sent_tips needs to be
1351          * sent to the other side.
1352          */
1353         if (sent_tips.nr) {
1354                 for_each_string_list_item(item, &src_tag) {
1355                         struct ref *ref = item->util;
1356                         struct ref *dst_ref;
1357                         struct commit *commit;
1358
1359                         if (is_null_oid(&ref->new_oid))
1360                                 continue;
1361                         commit = lookup_commit_reference_gently(ref->new_oid.hash, 1);
1362                         if (!commit)
1363                                 /* not pushing a commit, which is not an error */
1364                                 continue;
1365
1366                         /*
1367                          * Is this tag, which they do not have, reachable from
1368                          * any of the commits we are sending?
1369                          */
1370                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1371                                 continue;
1372
1373                         /* Add it in */
1374                         dst_ref = make_linked_ref(ref->name, dst_tail);
1375                         oidcpy(&dst_ref->new_oid, &ref->new_oid);
1376                         dst_ref->peer_ref = copy_ref(ref);
1377                 }
1378         }
1379         string_list_clear(&src_tag, 0);
1380         free(sent_tips.tip);
1381 }
1382
1383 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1384 {
1385         for ( ; list; list = list->next)
1386                 if (!strcmp(list->name, name))
1387                         return (struct ref *)list;
1388         return NULL;
1389 }
1390
1391 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1392 {
1393         for ( ; ref; ref = ref->next)
1394                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1395
1396         string_list_sort(ref_index);
1397 }
1398
1399 /*
1400  * Given only the set of local refs, sanity-check the set of push
1401  * refspecs. We can't catch all errors that match_push_refs would,
1402  * but we can catch some errors early before even talking to the
1403  * remote side.
1404  */
1405 int check_push_refs(struct ref *src, int nr_refspec, const char **refspec_names)
1406 {
1407         struct refspec *refspec = parse_push_refspec(nr_refspec, refspec_names);
1408         int ret = 0;
1409         int i;
1410
1411         for (i = 0; i < nr_refspec; i++) {
1412                 struct refspec *rs = refspec + i;
1413
1414                 if (rs->pattern || rs->matching)
1415                         continue;
1416
1417                 ret |= match_explicit_lhs(src, rs, NULL, NULL);
1418         }
1419
1420         free_refspec(nr_refspec, refspec);
1421         return ret;
1422 }
1423
1424 /*
1425  * Given the set of refs the local repository has, the set of refs the
1426  * remote repository has, and the refspec used for push, determine
1427  * what remote refs we will update and with what value by setting
1428  * peer_ref (which object is being pushed) and force (if the push is
1429  * forced) in elements of "dst". The function may add new elements to
1430  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1431  */
1432 int match_push_refs(struct ref *src, struct ref **dst,
1433                     int nr_refspec, const char **refspec, int flags)
1434 {
1435         struct refspec *rs;
1436         int send_all = flags & MATCH_REFS_ALL;
1437         int send_mirror = flags & MATCH_REFS_MIRROR;
1438         int send_prune = flags & MATCH_REFS_PRUNE;
1439         int errs;
1440         static const char *default_refspec[] = { ":", NULL };
1441         struct ref *ref, **dst_tail = tail_ref(dst);
1442         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1443
1444         if (!nr_refspec) {
1445                 nr_refspec = 1;
1446                 refspec = default_refspec;
1447         }
1448         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1449         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1450
1451         /* pick the remainder */
1452         for (ref = src; ref; ref = ref->next) {
1453                 struct string_list_item *dst_item;
1454                 struct ref *dst_peer;
1455                 const struct refspec *pat = NULL;
1456                 char *dst_name;
1457
1458                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1459                 if (!dst_name)
1460                         continue;
1461
1462                 if (!dst_ref_index.nr)
1463                         prepare_ref_index(&dst_ref_index, *dst);
1464
1465                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1466                 dst_peer = dst_item ? dst_item->util : NULL;
1467                 if (dst_peer) {
1468                         if (dst_peer->peer_ref)
1469                                 /* We're already sending something to this ref. */
1470                                 goto free_name;
1471                 } else {
1472                         if (pat->matching && !(send_all || send_mirror))
1473                                 /*
1474                                  * Remote doesn't have it, and we have no
1475                                  * explicit pattern, and we don't have
1476                                  * --all or --mirror.
1477                                  */
1478                                 goto free_name;
1479
1480                         /* Create a new one and link it */
1481                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1482                         oidcpy(&dst_peer->new_oid, &ref->new_oid);
1483                         string_list_insert(&dst_ref_index,
1484                                 dst_peer->name)->util = dst_peer;
1485                 }
1486                 dst_peer->peer_ref = copy_ref(ref);
1487                 dst_peer->force = pat->force;
1488         free_name:
1489                 free(dst_name);
1490         }
1491
1492         string_list_clear(&dst_ref_index, 0);
1493
1494         if (flags & MATCH_REFS_FOLLOW_TAGS)
1495                 add_missing_tags(src, dst, &dst_tail);
1496
1497         if (send_prune) {
1498                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1499                 /* check for missing refs on the remote */
1500                 for (ref = *dst; ref; ref = ref->next) {
1501                         char *src_name;
1502
1503                         if (ref->peer_ref)
1504                                 /* We're already sending something to this ref. */
1505                                 continue;
1506
1507                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1508                         if (src_name) {
1509                                 if (!src_ref_index.nr)
1510                                         prepare_ref_index(&src_ref_index, src);
1511                                 if (!string_list_has_string(&src_ref_index,
1512                                             src_name))
1513                                         ref->peer_ref = alloc_delete_ref();
1514                                 free(src_name);
1515                         }
1516                 }
1517                 string_list_clear(&src_ref_index, 0);
1518         }
1519         if (errs)
1520                 return -1;
1521         return 0;
1522 }
1523
1524 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1525                              int force_update)
1526 {
1527         struct ref *ref;
1528
1529         for (ref = remote_refs; ref; ref = ref->next) {
1530                 int force_ref_update = ref->force || force_update;
1531                 int reject_reason = 0;
1532
1533                 if (ref->peer_ref)
1534                         oidcpy(&ref->new_oid, &ref->peer_ref->new_oid);
1535                 else if (!send_mirror)
1536                         continue;
1537
1538                 ref->deletion = is_null_oid(&ref->new_oid);
1539                 if (!ref->deletion &&
1540                         !oidcmp(&ref->old_oid, &ref->new_oid)) {
1541                         ref->status = REF_STATUS_UPTODATE;
1542                         continue;
1543                 }
1544
1545                 /*
1546                  * If the remote ref has moved and is now different
1547                  * from what we expect, reject any push.
1548                  *
1549                  * It also is an error if the user told us to check
1550                  * with the remote-tracking branch to find the value
1551                  * to expect, but we did not have such a tracking
1552                  * branch.
1553                  */
1554                 if (ref->expect_old_sha1) {
1555                         if (oidcmp(&ref->old_oid, &ref->old_oid_expect))
1556                                 reject_reason = REF_STATUS_REJECT_STALE;
1557                         else
1558                                 /* If the ref isn't stale then force the update. */
1559                                 force_ref_update = 1;
1560                 }
1561
1562                 /*
1563                  * If the update isn't already rejected then check
1564                  * the usual "must fast-forward" rules.
1565                  *
1566                  * Decide whether an individual refspec A:B can be
1567                  * pushed.  The push will succeed if any of the
1568                  * following are true:
1569                  *
1570                  * (1) the remote reference B does not exist
1571                  *
1572                  * (2) the remote reference B is being removed (i.e.,
1573                  *     pushing :B where no source is specified)
1574                  *
1575                  * (3) the destination is not under refs/tags/, and
1576                  *     if the old and new value is a commit, the new
1577                  *     is a descendant of the old.
1578                  *
1579                  * (4) it is forced using the +A:B notation, or by
1580                  *     passing the --force argument
1581                  */
1582
1583                 if (!reject_reason && !ref->deletion && !is_null_oid(&ref->old_oid)) {
1584                         if (starts_with(ref->name, "refs/tags/"))
1585                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1586                         else if (!has_object_file(&ref->old_oid))
1587                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1588                         else if (!lookup_commit_reference_gently(ref->old_oid.hash, 1) ||
1589                                  !lookup_commit_reference_gently(ref->new_oid.hash, 1))
1590                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1591                         else if (!ref_newer(&ref->new_oid, &ref->old_oid))
1592                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1593                 }
1594
1595                 /*
1596                  * "--force" will defeat any rejection implemented
1597                  * by the rules above.
1598                  */
1599                 if (!force_ref_update)
1600                         ref->status = reject_reason;
1601                 else if (reject_reason)
1602                         ref->forced_update = 1;
1603         }
1604 }
1605
1606 static void set_merge(struct branch *ret)
1607 {
1608         struct remote *remote;
1609         char *ref;
1610         struct object_id oid;
1611         int i;
1612
1613         if (!ret)
1614                 return; /* no branch */
1615         if (ret->merge)
1616                 return; /* already run */
1617         if (!ret->remote_name || !ret->merge_nr) {
1618                 /*
1619                  * no merge config; let's make sure we don't confuse callers
1620                  * with a non-zero merge_nr but a NULL merge
1621                  */
1622                 ret->merge_nr = 0;
1623                 return;
1624         }
1625
1626         remote = remote_get(ret->remote_name);
1627
1628         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1629         for (i = 0; i < ret->merge_nr; i++) {
1630                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1631                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1632                 if (!remote_find_tracking(remote, ret->merge[i]) ||
1633                     strcmp(ret->remote_name, "."))
1634                         continue;
1635                 if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
1636                              oid.hash, &ref) == 1)
1637                         ret->merge[i]->dst = ref;
1638                 else
1639                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1640         }
1641 }
1642
1643 struct branch *branch_get(const char *name)
1644 {
1645         struct branch *ret;
1646
1647         read_config();
1648         if (!name || !*name || !strcmp(name, "HEAD"))
1649                 ret = current_branch;
1650         else
1651                 ret = make_branch(name, 0);
1652         set_merge(ret);
1653         return ret;
1654 }
1655
1656 int branch_has_merge_config(struct branch *branch)
1657 {
1658         return branch && !!branch->merge;
1659 }
1660
1661 int branch_merge_matches(struct branch *branch,
1662                                  int i,
1663                                  const char *refname)
1664 {
1665         if (!branch || i < 0 || i >= branch->merge_nr)
1666                 return 0;
1667         return refname_match(branch->merge[i]->src, refname);
1668 }
1669
1670 __attribute__((format (printf,2,3)))
1671 static const char *error_buf(struct strbuf *err, const char *fmt, ...)
1672 {
1673         if (err) {
1674                 va_list ap;
1675                 va_start(ap, fmt);
1676                 strbuf_vaddf(err, fmt, ap);
1677                 va_end(ap);
1678         }
1679         return NULL;
1680 }
1681
1682 const char *branch_get_upstream(struct branch *branch, struct strbuf *err)
1683 {
1684         if (!branch)
1685                 return error_buf(err, _("HEAD does not point to a branch"));
1686
1687         if (!branch->merge || !branch->merge[0]) {
1688                 /*
1689                  * no merge config; is it because the user didn't define any,
1690                  * or because it is not a real branch, and get_branch
1691                  * auto-vivified it?
1692                  */
1693                 if (!ref_exists(branch->refname))
1694                         return error_buf(err, _("no such branch: '%s'"),
1695                                          branch->name);
1696                 return error_buf(err,
1697                                  _("no upstream configured for branch '%s'"),
1698                                  branch->name);
1699         }
1700
1701         if (!branch->merge[0]->dst)
1702                 return error_buf(err,
1703                                  _("upstream branch '%s' not stored as a remote-tracking branch"),
1704                                  branch->merge[0]->src);
1705
1706         return branch->merge[0]->dst;
1707 }
1708
1709 static const char *tracking_for_push_dest(struct remote *remote,
1710                                           const char *refname,
1711                                           struct strbuf *err)
1712 {
1713         char *ret;
1714
1715         ret = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
1716         if (!ret)
1717                 return error_buf(err,
1718                                  _("push destination '%s' on remote '%s' has no local tracking branch"),
1719                                  refname, remote->name);
1720         return ret;
1721 }
1722
1723 static const char *branch_get_push_1(struct branch *branch, struct strbuf *err)
1724 {
1725         struct remote *remote;
1726
1727         remote = remote_get(pushremote_for_branch(branch, NULL));
1728         if (!remote)
1729                 return error_buf(err,
1730                                  _("branch '%s' has no remote for pushing"),
1731                                  branch->name);
1732
1733         if (remote->push_refspec_nr) {
1734                 char *dst;
1735                 const char *ret;
1736
1737                 dst = apply_refspecs(remote->push, remote->push_refspec_nr,
1738                                      branch->refname);
1739                 if (!dst)
1740                         return error_buf(err,
1741                                          _("push refspecs for '%s' do not include '%s'"),
1742                                          remote->name, branch->name);
1743
1744                 ret = tracking_for_push_dest(remote, dst, err);
1745                 free(dst);
1746                 return ret;
1747         }
1748
1749         if (remote->mirror)
1750                 return tracking_for_push_dest(remote, branch->refname, err);
1751
1752         switch (push_default) {
1753         case PUSH_DEFAULT_NOTHING:
1754                 return error_buf(err, _("push has no destination (push.default is 'nothing')"));
1755
1756         case PUSH_DEFAULT_MATCHING:
1757         case PUSH_DEFAULT_CURRENT:
1758                 return tracking_for_push_dest(remote, branch->refname, err);
1759
1760         case PUSH_DEFAULT_UPSTREAM:
1761                 return branch_get_upstream(branch, err);
1762
1763         case PUSH_DEFAULT_UNSPECIFIED:
1764         case PUSH_DEFAULT_SIMPLE:
1765                 {
1766                         const char *up, *cur;
1767
1768                         up = branch_get_upstream(branch, err);
1769                         if (!up)
1770                                 return NULL;
1771                         cur = tracking_for_push_dest(remote, branch->refname, err);
1772                         if (!cur)
1773                                 return NULL;
1774                         if (strcmp(cur, up))
1775                                 return error_buf(err,
1776                                                  _("cannot resolve 'simple' push to a single destination"));
1777                         return cur;
1778                 }
1779         }
1780
1781         die("BUG: unhandled push situation");
1782 }
1783
1784 const char *branch_get_push(struct branch *branch, struct strbuf *err)
1785 {
1786         if (!branch)
1787                 return error_buf(err, _("HEAD does not point to a branch"));
1788
1789         if (!branch->push_tracking_ref)
1790                 branch->push_tracking_ref = branch_get_push_1(branch, err);
1791         return branch->push_tracking_ref;
1792 }
1793
1794 static int ignore_symref_update(const char *refname)
1795 {
1796         struct object_id oid;
1797         int flag;
1798
1799         if (!resolve_ref_unsafe(refname, 0, oid.hash, &flag))
1800                 return 0; /* non-existing refs are OK */
1801         return (flag & REF_ISSYMREF);
1802 }
1803
1804 /*
1805  * Create and return a list of (struct ref) consisting of copies of
1806  * each remote_ref that matches refspec.  refspec must be a pattern.
1807  * Fill in the copies' peer_ref to describe the local tracking refs to
1808  * which they map.  Omit any references that would map to an existing
1809  * local symbolic ref.
1810  */
1811 static struct ref *get_expanded_map(const struct ref *remote_refs,
1812                                     const struct refspec *refspec)
1813 {
1814         const struct ref *ref;
1815         struct ref *ret = NULL;
1816         struct ref **tail = &ret;
1817
1818         for (ref = remote_refs; ref; ref = ref->next) {
1819                 char *expn_name = NULL;
1820
1821                 if (strchr(ref->name, '^'))
1822                         continue; /* a dereference item */
1823                 if (match_name_with_pattern(refspec->src, ref->name,
1824                                             refspec->dst, &expn_name) &&
1825                     !ignore_symref_update(expn_name)) {
1826                         struct ref *cpy = copy_ref(ref);
1827
1828                         cpy->peer_ref = alloc_ref(expn_name);
1829                         if (refspec->force)
1830                                 cpy->peer_ref->force = 1;
1831                         *tail = cpy;
1832                         tail = &cpy->next;
1833                 }
1834                 free(expn_name);
1835         }
1836
1837         return ret;
1838 }
1839
1840 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1841 {
1842         const struct ref *ref;
1843         for (ref = refs; ref; ref = ref->next) {
1844                 if (refname_match(name, ref->name))
1845                         return ref;
1846         }
1847         return NULL;
1848 }
1849
1850 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1851 {
1852         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1853
1854         if (!ref)
1855                 return NULL;
1856
1857         return copy_ref(ref);
1858 }
1859
1860 static struct ref *get_local_ref(const char *name)
1861 {
1862         if (!name || name[0] == '\0')
1863                 return NULL;
1864
1865         if (starts_with(name, "refs/"))
1866                 return alloc_ref(name);
1867
1868         if (starts_with(name, "heads/") ||
1869             starts_with(name, "tags/") ||
1870             starts_with(name, "remotes/"))
1871                 return alloc_ref_with_prefix("refs/", 5, name);
1872
1873         return alloc_ref_with_prefix("refs/heads/", 11, name);
1874 }
1875
1876 int get_fetch_map(const struct ref *remote_refs,
1877                   const struct refspec *refspec,
1878                   struct ref ***tail,
1879                   int missing_ok)
1880 {
1881         struct ref *ref_map, **rmp;
1882
1883         if (refspec->pattern) {
1884                 ref_map = get_expanded_map(remote_refs, refspec);
1885         } else {
1886                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1887
1888                 if (refspec->exact_sha1) {
1889                         ref_map = alloc_ref(name);
1890                         get_oid_hex(name, &ref_map->old_oid);
1891                 } else {
1892                         ref_map = get_remote_ref(remote_refs, name);
1893                 }
1894                 if (!missing_ok && !ref_map)
1895                         die("Couldn't find remote ref %s", name);
1896                 if (ref_map) {
1897                         ref_map->peer_ref = get_local_ref(refspec->dst);
1898                         if (ref_map->peer_ref && refspec->force)
1899                                 ref_map->peer_ref->force = 1;
1900                 }
1901         }
1902
1903         for (rmp = &ref_map; *rmp; ) {
1904                 if ((*rmp)->peer_ref) {
1905                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1906                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1907                                 struct ref *ignore = *rmp;
1908                                 error("* Ignoring funny ref '%s' locally",
1909                                       (*rmp)->peer_ref->name);
1910                                 *rmp = (*rmp)->next;
1911                                 free(ignore->peer_ref);
1912                                 free(ignore);
1913                                 continue;
1914                         }
1915                 }
1916                 rmp = &((*rmp)->next);
1917         }
1918
1919         if (ref_map)
1920                 tail_link_ref(ref_map, tail);
1921
1922         return 0;
1923 }
1924
1925 int resolve_remote_symref(struct ref *ref, struct ref *list)
1926 {
1927         if (!ref->symref)
1928                 return 0;
1929         for (; list; list = list->next)
1930                 if (!strcmp(ref->symref, list->name)) {
1931                         oidcpy(&ref->old_oid, &list->old_oid);
1932                         return 0;
1933                 }
1934         return 1;
1935 }
1936
1937 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1938 {
1939         while (list) {
1940                 struct commit *commit = pop_commit(&list);
1941                 commit->object.flags &= ~mark;
1942         }
1943 }
1944
1945 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
1946 {
1947         struct object *o;
1948         struct commit *old, *new;
1949         struct commit_list *list, *used;
1950         int found = 0;
1951
1952         /*
1953          * Both new and old must be commit-ish and new is descendant of
1954          * old.  Otherwise we require --force.
1955          */
1956         o = deref_tag(parse_object(old_oid->hash), NULL, 0);
1957         if (!o || o->type != OBJ_COMMIT)
1958                 return 0;
1959         old = (struct commit *) o;
1960
1961         o = deref_tag(parse_object(new_oid->hash), NULL, 0);
1962         if (!o || o->type != OBJ_COMMIT)
1963                 return 0;
1964         new = (struct commit *) o;
1965
1966         if (parse_commit(new) < 0)
1967                 return 0;
1968
1969         used = list = NULL;
1970         commit_list_insert(new, &list);
1971         while (list) {
1972                 new = pop_most_recent_commit(&list, TMP_MARK);
1973                 commit_list_insert(new, &used);
1974                 if (new == old) {
1975                         found = 1;
1976                         break;
1977                 }
1978         }
1979         unmark_and_free(list, TMP_MARK);
1980         unmark_and_free(used, TMP_MARK);
1981         return found;
1982 }
1983
1984 /*
1985  * Compare a branch with its upstream, and save their differences (number
1986  * of commits) in *num_ours and *num_theirs. The name of the upstream branch
1987  * (or NULL if no upstream is defined) is returned via *upstream_name, if it
1988  * is not itself NULL.
1989  *
1990  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
1991  * upstream defined, or ref does not exist), 0 otherwise.
1992  */
1993 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
1994                        const char **upstream_name)
1995 {
1996         struct object_id oid;
1997         struct commit *ours, *theirs;
1998         struct rev_info revs;
1999         const char *base;
2000         struct argv_array argv = ARGV_ARRAY_INIT;
2001
2002         /* Cannot stat unless we are marked to build on top of somebody else. */
2003         base = branch_get_upstream(branch, NULL);
2004         if (upstream_name)
2005                 *upstream_name = base;
2006         if (!base)
2007                 return -1;
2008
2009         /* Cannot stat if what we used to build on no longer exists */
2010         if (read_ref(base, oid.hash))
2011                 return -1;
2012         theirs = lookup_commit_reference(oid.hash);
2013         if (!theirs)
2014                 return -1;
2015
2016         if (read_ref(branch->refname, oid.hash))
2017                 return -1;
2018         ours = lookup_commit_reference(oid.hash);
2019         if (!ours)
2020                 return -1;
2021
2022         /* are we the same? */
2023         if (theirs == ours) {
2024                 *num_theirs = *num_ours = 0;
2025                 return 0;
2026         }
2027
2028         /* Run "rev-list --left-right ours...theirs" internally... */
2029         argv_array_push(&argv, ""); /* ignored */
2030         argv_array_push(&argv, "--left-right");
2031         argv_array_pushf(&argv, "%s...%s",
2032                          oid_to_hex(&ours->object.oid),
2033                          oid_to_hex(&theirs->object.oid));
2034         argv_array_push(&argv, "--");
2035
2036         init_revisions(&revs, NULL);
2037         setup_revisions(argv.argc, argv.argv, &revs, NULL);
2038         if (prepare_revision_walk(&revs))
2039                 die("revision walk setup failed");
2040
2041         /* ... and count the commits on each side. */
2042         *num_ours = 0;
2043         *num_theirs = 0;
2044         while (1) {
2045                 struct commit *c = get_revision(&revs);
2046                 if (!c)
2047                         break;
2048                 if (c->object.flags & SYMMETRIC_LEFT)
2049                         (*num_ours)++;
2050                 else
2051                         (*num_theirs)++;
2052         }
2053
2054         /* clear object flags smudged by the above traversal */
2055         clear_commit_marks(ours, ALL_REV_FLAGS);
2056         clear_commit_marks(theirs, ALL_REV_FLAGS);
2057
2058         argv_array_clear(&argv);
2059         return 0;
2060 }
2061
2062 /*
2063  * Return true when there is anything to report, otherwise false.
2064  */
2065 int format_tracking_info(struct branch *branch, struct strbuf *sb)
2066 {
2067         int ours, theirs;
2068         const char *full_base;
2069         char *base;
2070         int upstream_is_gone = 0;
2071
2072         if (stat_tracking_info(branch, &ours, &theirs, &full_base) < 0) {
2073                 if (!full_base)
2074                         return 0;
2075                 upstream_is_gone = 1;
2076         }
2077
2078         base = shorten_unambiguous_ref(full_base, 0);
2079         if (upstream_is_gone) {
2080                 strbuf_addf(sb,
2081                         _("Your branch is based on '%s', but the upstream is gone.\n"),
2082                         base);
2083                 if (advice_status_hints)
2084                         strbuf_addstr(sb,
2085                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
2086         } else if (!ours && !theirs) {
2087                 strbuf_addf(sb,
2088                         _("Your branch is up-to-date with '%s'.\n"),
2089                         base);
2090         } else if (!theirs) {
2091                 strbuf_addf(sb,
2092                         Q_("Your branch is ahead of '%s' by %d commit.\n",
2093                            "Your branch is ahead of '%s' by %d commits.\n",
2094                            ours),
2095                         base, ours);
2096                 if (advice_status_hints)
2097                         strbuf_addstr(sb,
2098                                 _("  (use \"git push\" to publish your local commits)\n"));
2099         } else if (!ours) {
2100                 strbuf_addf(sb,
2101                         Q_("Your branch is behind '%s' by %d commit, "
2102                                "and can be fast-forwarded.\n",
2103                            "Your branch is behind '%s' by %d commits, "
2104                                "and can be fast-forwarded.\n",
2105                            theirs),
2106                         base, theirs);
2107                 if (advice_status_hints)
2108                         strbuf_addstr(sb,
2109                                 _("  (use \"git pull\" to update your local branch)\n"));
2110         } else {
2111                 strbuf_addf(sb,
2112                         Q_("Your branch and '%s' have diverged,\n"
2113                                "and have %d and %d different commit each, "
2114                                "respectively.\n",
2115                            "Your branch and '%s' have diverged,\n"
2116                                "and have %d and %d different commits each, "
2117                                "respectively.\n",
2118                            ours + theirs),
2119                         base, ours, theirs);
2120                 if (advice_status_hints)
2121                         strbuf_addstr(sb,
2122                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
2123         }
2124         free(base);
2125         return 1;
2126 }
2127
2128 static int one_local_ref(const char *refname, const struct object_id *oid,
2129                          int flag, void *cb_data)
2130 {
2131         struct ref ***local_tail = cb_data;
2132         struct ref *ref;
2133
2134         /* we already know it starts with refs/ to get here */
2135         if (check_refname_format(refname + 5, 0))
2136                 return 0;
2137
2138         ref = alloc_ref(refname);
2139         oidcpy(&ref->new_oid, oid);
2140         **local_tail = ref;
2141         *local_tail = &ref->next;
2142         return 0;
2143 }
2144
2145 struct ref *get_local_heads(void)
2146 {
2147         struct ref *local_refs = NULL, **local_tail = &local_refs;
2148
2149         for_each_ref(one_local_ref, &local_tail);
2150         return local_refs;
2151 }
2152
2153 struct ref *guess_remote_head(const struct ref *head,
2154                               const struct ref *refs,
2155                               int all)
2156 {
2157         const struct ref *r;
2158         struct ref *list = NULL;
2159         struct ref **tail = &list;
2160
2161         if (!head)
2162                 return NULL;
2163
2164         /*
2165          * Some transports support directly peeking at
2166          * where HEAD points; if that is the case, then
2167          * we don't have to guess.
2168          */
2169         if (head->symref)
2170                 return copy_ref(find_ref_by_name(refs, head->symref));
2171
2172         /* If refs/heads/master could be right, it is. */
2173         if (!all) {
2174                 r = find_ref_by_name(refs, "refs/heads/master");
2175                 if (r && !oidcmp(&r->old_oid, &head->old_oid))
2176                         return copy_ref(r);
2177         }
2178
2179         /* Look for another ref that points there */
2180         for (r = refs; r; r = r->next) {
2181                 if (r != head &&
2182                     starts_with(r->name, "refs/heads/") &&
2183                     !oidcmp(&r->old_oid, &head->old_oid)) {
2184                         *tail = copy_ref(r);
2185                         tail = &((*tail)->next);
2186                         if (!all)
2187                                 break;
2188                 }
2189         }
2190
2191         return list;
2192 }
2193
2194 struct stale_heads_info {
2195         struct string_list *ref_names;
2196         struct ref **stale_refs_tail;
2197         struct refspec *refs;
2198         int ref_count;
2199 };
2200
2201 static int get_stale_heads_cb(const char *refname, const struct object_id *oid,
2202                               int flags, void *cb_data)
2203 {
2204         struct stale_heads_info *info = cb_data;
2205         struct string_list matches = STRING_LIST_INIT_DUP;
2206         struct refspec query;
2207         int i, stale = 1;
2208         memset(&query, 0, sizeof(struct refspec));
2209         query.dst = (char *)refname;
2210
2211         query_refspecs_multiple(info->refs, info->ref_count, &query, &matches);
2212         if (matches.nr == 0)
2213                 goto clean_exit; /* No matches */
2214
2215         /*
2216          * If we did find a suitable refspec and it's not a symref and
2217          * it's not in the list of refs that currently exist in that
2218          * remote, we consider it to be stale. In order to deal with
2219          * overlapping refspecs, we need to go over all of the
2220          * matching refs.
2221          */
2222         if (flags & REF_ISSYMREF)
2223                 goto clean_exit;
2224
2225         for (i = 0; stale && i < matches.nr; i++)
2226                 if (string_list_has_string(info->ref_names, matches.items[i].string))
2227                         stale = 0;
2228
2229         if (stale) {
2230                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2231                 oidcpy(&ref->new_oid, oid);
2232         }
2233
2234 clean_exit:
2235         string_list_clear(&matches, 0);
2236         return 0;
2237 }
2238
2239 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
2240 {
2241         struct ref *ref, *stale_refs = NULL;
2242         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2243         struct stale_heads_info info;
2244
2245         info.ref_names = &ref_names;
2246         info.stale_refs_tail = &stale_refs;
2247         info.refs = refs;
2248         info.ref_count = ref_count;
2249         for (ref = fetch_map; ref; ref = ref->next)
2250                 string_list_append(&ref_names, ref->name);
2251         string_list_sort(&ref_names);
2252         for_each_ref(get_stale_heads_cb, &info);
2253         string_list_clear(&ref_names, 0);
2254         return stale_refs;
2255 }
2256
2257 /*
2258  * Compare-and-swap
2259  */
2260 static void clear_cas_option(struct push_cas_option *cas)
2261 {
2262         int i;
2263
2264         for (i = 0; i < cas->nr; i++)
2265                 free(cas->entry[i].refname);
2266         free(cas->entry);
2267         memset(cas, 0, sizeof(*cas));
2268 }
2269
2270 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2271                                       const char *refname,
2272                                       size_t refnamelen)
2273 {
2274         struct push_cas *entry;
2275         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2276         entry = &cas->entry[cas->nr++];
2277         memset(entry, 0, sizeof(*entry));
2278         entry->refname = xmemdupz(refname, refnamelen);
2279         return entry;
2280 }
2281
2282 int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2283 {
2284         const char *colon;
2285         struct push_cas *entry;
2286
2287         if (unset) {
2288                 /* "--no-<option>" */
2289                 clear_cas_option(cas);
2290                 return 0;
2291         }
2292
2293         if (!arg) {
2294                 /* just "--<option>" */
2295                 cas->use_tracking_for_rest = 1;
2296                 return 0;
2297         }
2298
2299         /* "--<option>=refname" or "--<option>=refname:value" */
2300         colon = strchrnul(arg, ':');
2301         entry = add_cas_entry(cas, arg, colon - arg);
2302         if (!*colon)
2303                 entry->use_tracking = 1;
2304         else if (!colon[1])
2305                 hashclr(entry->expect);
2306         else if (get_sha1(colon + 1, entry->expect))
2307                 return error("cannot parse expected object name '%s'", colon + 1);
2308         return 0;
2309 }
2310
2311 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2312 {
2313         return parse_push_cas_option(opt->value, arg, unset);
2314 }
2315
2316 int is_empty_cas(const struct push_cas_option *cas)
2317 {
2318         return !cas->use_tracking_for_rest && !cas->nr;
2319 }
2320
2321 /*
2322  * Look at remote.fetch refspec and see if we have a remote
2323  * tracking branch for the refname there.  Fill its current
2324  * value in sha1[].
2325  * If we cannot do so, return negative to signal an error.
2326  */
2327 static int remote_tracking(struct remote *remote, const char *refname,
2328                            struct object_id *oid)
2329 {
2330         char *dst;
2331
2332         dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
2333         if (!dst)
2334                 return -1; /* no tracking ref for refname at remote */
2335         if (read_ref(dst, oid->hash))
2336                 return -1; /* we know what the tracking ref is but we cannot read it */
2337         return 0;
2338 }
2339
2340 static void apply_cas(struct push_cas_option *cas,
2341                       struct remote *remote,
2342                       struct ref *ref)
2343 {
2344         int i;
2345
2346         /* Find an explicit --<option>=<name>[:<value>] entry */
2347         for (i = 0; i < cas->nr; i++) {
2348                 struct push_cas *entry = &cas->entry[i];
2349                 if (!refname_match(entry->refname, ref->name))
2350                         continue;
2351                 ref->expect_old_sha1 = 1;
2352                 if (!entry->use_tracking)
2353                         hashcpy(ref->old_oid_expect.hash, cas->entry[i].expect);
2354                 else if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2355                         oidclr(&ref->old_oid_expect);
2356                 return;
2357         }
2358
2359         /* Are we using "--<option>" to cover all? */
2360         if (!cas->use_tracking_for_rest)
2361                 return;
2362
2363         ref->expect_old_sha1 = 1;
2364         if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2365                 oidclr(&ref->old_oid_expect);
2366 }
2367
2368 void apply_push_cas(struct push_cas_option *cas,
2369                     struct remote *remote,
2370                     struct ref *remote_refs)
2371 {
2372         struct ref *ref;
2373         for (ref = remote_refs; ref; ref = ref->next)
2374                 apply_cas(cas, remote, ref);
2375 }