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