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