merge: refuse to create too cool a merge by default
[git] / remote.c
1 #include "cache.h"
2 #include "remote.h"
3 #include "refs.h"
4 #include "commit.h"
5 #include "diff.h"
6 #include "revision.h"
7 #include "dir.h"
8 #include "tag.h"
9 #include "string-list.h"
10 #include "mergesort.h"
11 #include "argv-array.h"
12
13 enum map_direction { FROM_SRC, FROM_DST };
14
15 static struct refspec s_tag_refspec = {
16         0,
17         1,
18         0,
19         0,
20         "refs/tags/*",
21         "refs/tags/*"
22 };
23
24 const struct refspec *tag_refspec = &s_tag_refspec;
25
26 struct counted_string {
27         size_t len;
28         const char *s;
29 };
30 struct rewrite {
31         const char *base;
32         size_t baselen;
33         struct counted_string *instead_of;
34         int instead_of_nr;
35         int instead_of_alloc;
36 };
37 struct rewrites {
38         struct rewrite **rewrite;
39         int rewrite_alloc;
40         int rewrite_nr;
41 };
42
43 static struct remote **remotes;
44 static int remotes_alloc;
45 static int remotes_nr;
46 static struct hashmap remotes_hash;
47
48 static struct branch **branches;
49 static int branches_alloc;
50 static int branches_nr;
51
52 static struct branch *current_branch;
53 static const char *pushremote_name;
54
55 static struct rewrites rewrites;
56 static struct rewrites rewrites_push;
57
58 static int valid_remote(const struct remote *remote)
59 {
60         return (!!remote->url) || (!!remote->foreign_vcs);
61 }
62
63 static const char *alias_url(const char *url, struct rewrites *r)
64 {
65         int i, j;
66         struct counted_string *longest;
67         int longest_i;
68
69         longest = NULL;
70         longest_i = -1;
71         for (i = 0; i < r->rewrite_nr; i++) {
72                 if (!r->rewrite[i])
73                         continue;
74                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
75                         if (starts_with(url, r->rewrite[i]->instead_of[j].s) &&
76                             (!longest ||
77                              longest->len < r->rewrite[i]->instead_of[j].len)) {
78                                 longest = &(r->rewrite[i]->instead_of[j]);
79                                 longest_i = i;
80                         }
81                 }
82         }
83         if (!longest)
84                 return url;
85
86         return xstrfmt("%s%s", r->rewrite[longest_i]->base, url + longest->len);
87 }
88
89 static void add_push_refspec(struct remote *remote, const char *ref)
90 {
91         ALLOC_GROW(remote->push_refspec,
92                    remote->push_refspec_nr + 1,
93                    remote->push_refspec_alloc);
94         remote->push_refspec[remote->push_refspec_nr++] = ref;
95 }
96
97 static void add_fetch_refspec(struct remote *remote, const char *ref)
98 {
99         ALLOC_GROW(remote->fetch_refspec,
100                    remote->fetch_refspec_nr + 1,
101                    remote->fetch_refspec_alloc);
102         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
103 }
104
105 static void add_url(struct remote *remote, const char *url)
106 {
107         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
108         remote->url[remote->url_nr++] = url;
109 }
110
111 static void add_pushurl(struct remote *remote, const char *pushurl)
112 {
113         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
114         remote->pushurl[remote->pushurl_nr++] = pushurl;
115 }
116
117 static void add_pushurl_alias(struct remote *remote, const char *url)
118 {
119         const char *pushurl = alias_url(url, &rewrites_push);
120         if (pushurl != url)
121                 add_pushurl(remote, pushurl);
122 }
123
124 static void add_url_alias(struct remote *remote, const char *url)
125 {
126         add_url(remote, alias_url(url, &rewrites));
127         add_pushurl_alias(remote, url);
128 }
129
130 struct remotes_hash_key {
131         const char *str;
132         int len;
133 };
134
135 static int remotes_hash_cmp(const struct remote *a, const struct remote *b, const struct remotes_hash_key *key)
136 {
137         if (key)
138                 return strncmp(a->name, key->str, key->len) || a->name[key->len];
139         else
140                 return strcmp(a->name, b->name);
141 }
142
143 static inline void init_remotes_hash(void)
144 {
145         if (!remotes_hash.cmpfn)
146                 hashmap_init(&remotes_hash, (hashmap_cmp_fn)remotes_hash_cmp, 0);
147 }
148
149 static struct remote *make_remote(const char *name, int len)
150 {
151         struct remote *ret, *replaced;
152         struct remotes_hash_key lookup;
153         struct hashmap_entry lookup_entry;
154
155         if (!len)
156                 len = strlen(name);
157
158         init_remotes_hash();
159         lookup.str = name;
160         lookup.len = len;
161         hashmap_entry_init(&lookup_entry, memhash(name, len));
162
163         if ((ret = hashmap_get(&remotes_hash, &lookup_entry, &lookup)) != NULL)
164                 return ret;
165
166         ret = xcalloc(1, sizeof(struct remote));
167         ret->prune = -1;  /* unspecified */
168         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
169         remotes[remotes_nr++] = ret;
170         ret->name = xstrndup(name, len);
171
172         hashmap_entry_init(ret, lookup_entry.hash);
173         replaced = hashmap_put(&remotes_hash, ret);
174         assert(replaced == NULL);  /* no previous entry overwritten */
175         return ret;
176 }
177
178 static void add_merge(struct branch *branch, const char *name)
179 {
180         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
181                    branch->merge_alloc);
182         branch->merge_name[branch->merge_nr++] = name;
183 }
184
185 static struct branch *make_branch(const char *name, int len)
186 {
187         struct branch *ret;
188         int i;
189
190         for (i = 0; i < branches_nr; i++) {
191                 if (len ? (!strncmp(name, branches[i]->name, len) &&
192                            !branches[i]->name[len]) :
193                     !strcmp(name, branches[i]->name))
194                         return branches[i];
195         }
196
197         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
198         ret = xcalloc(1, sizeof(struct branch));
199         branches[branches_nr++] = ret;
200         if (len)
201                 ret->name = xstrndup(name, len);
202         else
203                 ret->name = xstrdup(name);
204         ret->refname = xstrfmt("refs/heads/%s", ret->name);
205
206         return ret;
207 }
208
209 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
210 {
211         struct rewrite *ret;
212         int i;
213
214         for (i = 0; i < r->rewrite_nr; i++) {
215                 if (len
216                     ? (len == r->rewrite[i]->baselen &&
217                        !strncmp(base, r->rewrite[i]->base, len))
218                     : !strcmp(base, r->rewrite[i]->base))
219                         return r->rewrite[i];
220         }
221
222         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
223         ret = xcalloc(1, sizeof(struct rewrite));
224         r->rewrite[r->rewrite_nr++] = ret;
225         if (len) {
226                 ret->base = xstrndup(base, len);
227                 ret->baselen = len;
228         }
229         else {
230                 ret->base = xstrdup(base);
231                 ret->baselen = strlen(base);
232         }
233         return ret;
234 }
235
236 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
237 {
238         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
239         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
240         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
241         rewrite->instead_of_nr++;
242 }
243
244 static const char *skip_spaces(const char *s)
245 {
246         while (isspace(*s))
247                 s++;
248         return s;
249 }
250
251 static void read_remotes_file(struct remote *remote)
252 {
253         struct strbuf buf = STRBUF_INIT;
254         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
255
256         if (!f)
257                 return;
258         remote->origin = REMOTE_REMOTES;
259         while (strbuf_getline(&buf, f, '\n') != EOF) {
260                 const char *v;
261
262                 strbuf_rtrim(&buf);
263
264                 if (skip_prefix(buf.buf, "URL:", &v))
265                         add_url_alias(remote, xstrdup(skip_spaces(v)));
266                 else if (skip_prefix(buf.buf, "Push:", &v))
267                         add_push_refspec(remote, xstrdup(skip_spaces(v)));
268                 else if (skip_prefix(buf.buf, "Pull:", &v))
269                         add_fetch_refspec(remote, xstrdup(skip_spaces(v)));
270         }
271         strbuf_release(&buf);
272         fclose(f);
273 }
274
275 static void read_branches_file(struct remote *remote)
276 {
277         char *frag;
278         struct strbuf buf = STRBUF_INIT;
279         FILE *f = fopen(git_path("branches/%s", remote->name), "r");
280
281         if (!f)
282                 return;
283
284         strbuf_getline(&buf, f, '\n');
285         fclose(f);
286         strbuf_trim(&buf);
287         if (!buf.len) {
288                 strbuf_release(&buf);
289                 return;
290         }
291
292         remote->origin = REMOTE_BRANCHES;
293
294         /*
295          * The branches file would have URL and optionally
296          * #branch specified.  The "master" (or specified) branch is
297          * fetched and stored in the local branch matching the
298          * remote name.
299          */
300         frag = strchr(buf.buf, '#');
301         if (frag)
302                 *(frag++) = '\0';
303         else
304                 frag = "master";
305
306         add_url_alias(remote, strbuf_detach(&buf, NULL));
307         add_fetch_refspec(remote, xstrfmt("refs/heads/%s:refs/heads/%s",
308                                           frag, remote->name));
309
310         /*
311          * Cogito compatible push: push current HEAD to remote #branch
312          * (master if missing)
313          */
314         add_push_refspec(remote, xstrfmt("HEAD:refs/heads/%s", frag));
315         remote->fetch_tags = 1; /* always auto-follow */
316 }
317
318 static int handle_config(const char *key, const char *value, void *cb)
319 {
320         const char *name;
321         const char *subkey;
322         struct remote *remote;
323         struct branch *branch;
324         if (starts_with(key, "branch.")) {
325                 name = key + 7;
326                 subkey = strrchr(name, '.');
327                 if (!subkey)
328                         return 0;
329                 branch = make_branch(name, subkey - name);
330                 if (!strcmp(subkey, ".remote")) {
331                         return git_config_string(&branch->remote_name, key, value);
332                 } else if (!strcmp(subkey, ".pushremote")) {
333                         return git_config_string(&branch->pushremote_name, key, value);
334                 } else if (!strcmp(subkey, ".merge")) {
335                         if (!value)
336                                 return config_error_nonbool(key);
337                         add_merge(branch, xstrdup(value));
338                 }
339                 return 0;
340         }
341         if (starts_with(key, "url.")) {
342                 struct rewrite *rewrite;
343                 name = key + 4;
344                 subkey = strrchr(name, '.');
345                 if (!subkey)
346                         return 0;
347                 if (!strcmp(subkey, ".insteadof")) {
348                         rewrite = make_rewrite(&rewrites, name, subkey - name);
349                         if (!value)
350                                 return config_error_nonbool(key);
351                         add_instead_of(rewrite, xstrdup(value));
352                 } else if (!strcmp(subkey, ".pushinsteadof")) {
353                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
354                         if (!value)
355                                 return config_error_nonbool(key);
356                         add_instead_of(rewrite, xstrdup(value));
357                 }
358         }
359
360         if (!starts_with(key,  "remote."))
361                 return 0;
362         name = key + 7;
363
364         /* Handle remote.* variables */
365         if (!strcmp(name, "pushdefault"))
366                 return git_config_string(&pushremote_name, key, value);
367
368         /* Handle remote.<name>.* variables */
369         if (*name == '/') {
370                 warning("Config remote shorthand cannot begin with '/': %s",
371                         name);
372                 return 0;
373         }
374         subkey = strrchr(name, '.');
375         if (!subkey)
376                 return 0;
377         remote = make_remote(name, subkey - name);
378         remote->origin = REMOTE_CONFIG;
379         if (!strcmp(subkey, ".mirror"))
380                 remote->mirror = git_config_bool(key, value);
381         else if (!strcmp(subkey, ".skipdefaultupdate"))
382                 remote->skip_default_update = git_config_bool(key, value);
383         else if (!strcmp(subkey, ".skipfetchall"))
384                 remote->skip_default_update = git_config_bool(key, value);
385         else if (!strcmp(subkey, ".prune"))
386                 remote->prune = git_config_bool(key, value);
387         else if (!strcmp(subkey, ".url")) {
388                 const char *v;
389                 if (git_config_string(&v, key, value))
390                         return -1;
391                 add_url(remote, v);
392         } else if (!strcmp(subkey, ".pushurl")) {
393                 const char *v;
394                 if (git_config_string(&v, key, value))
395                         return -1;
396                 add_pushurl(remote, v);
397         } else if (!strcmp(subkey, ".push")) {
398                 const char *v;
399                 if (git_config_string(&v, key, value))
400                         return -1;
401                 add_push_refspec(remote, v);
402         } else if (!strcmp(subkey, ".fetch")) {
403                 const char *v;
404                 if (git_config_string(&v, key, value))
405                         return -1;
406                 add_fetch_refspec(remote, v);
407         } else if (!strcmp(subkey, ".receivepack")) {
408                 const char *v;
409                 if (git_config_string(&v, key, value))
410                         return -1;
411                 if (!remote->receivepack)
412                         remote->receivepack = v;
413                 else
414                         error("more than one receivepack given, using the first");
415         } else if (!strcmp(subkey, ".uploadpack")) {
416                 const char *v;
417                 if (git_config_string(&v, key, value))
418                         return -1;
419                 if (!remote->uploadpack)
420                         remote->uploadpack = v;
421                 else
422                         error("more than one uploadpack given, using the first");
423         } else if (!strcmp(subkey, ".tagopt")) {
424                 if (!strcmp(value, "--no-tags"))
425                         remote->fetch_tags = -1;
426                 else if (!strcmp(value, "--tags"))
427                         remote->fetch_tags = 2;
428         } else if (!strcmp(subkey, ".proxy")) {
429                 return git_config_string((const char **)&remote->http_proxy,
430                                          key, value);
431         } else if (!strcmp(subkey, ".vcs")) {
432                 return git_config_string(&remote->foreign_vcs, key, value);
433         }
434         return 0;
435 }
436
437 static void alias_all_urls(void)
438 {
439         int i, j;
440         for (i = 0; i < remotes_nr; i++) {
441                 int add_pushurl_aliases;
442                 if (!remotes[i])
443                         continue;
444                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
445                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
446                 }
447                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
448                 for (j = 0; j < remotes[i]->url_nr; j++) {
449                         if (add_pushurl_aliases)
450                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
451                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
452                 }
453         }
454 }
455
456 static void read_config(void)
457 {
458         static int loaded;
459         struct object_id oid;
460         const char *head_ref;
461         int flag;
462
463         if (loaded)
464                 return;
465         loaded = 1;
466
467         current_branch = NULL;
468         head_ref = resolve_ref_unsafe("HEAD", 0, oid.hash, &flag);
469         if (head_ref && (flag & REF_ISSYMREF) &&
470             skip_prefix(head_ref, "refs/heads/", &head_ref)) {
471                 current_branch = make_branch(head_ref, 0);
472         }
473         git_config(handle_config, NULL);
474         alias_all_urls();
475 }
476
477 /*
478  * This function frees a refspec array.
479  * Warning: code paths should be checked to ensure that the src
480  *          and dst pointers are always freeable pointers as well
481  *          as the refspec pointer itself.
482  */
483 static void free_refspecs(struct refspec *refspec, int nr_refspec)
484 {
485         int i;
486
487         if (!refspec)
488                 return;
489
490         for (i = 0; i < nr_refspec; i++) {
491                 free(refspec[i].src);
492                 free(refspec[i].dst);
493         }
494         free(refspec);
495 }
496
497 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
498 {
499         int i;
500         struct refspec *rs = xcalloc(nr_refspec, sizeof(*rs));
501
502         for (i = 0; i < nr_refspec; i++) {
503                 size_t llen;
504                 int is_glob;
505                 const char *lhs, *rhs;
506                 int flags;
507
508                 is_glob = 0;
509
510                 lhs = refspec[i];
511                 if (*lhs == '+') {
512                         rs[i].force = 1;
513                         lhs++;
514                 }
515
516                 rhs = strrchr(lhs, ':');
517
518                 /*
519                  * Before going on, special case ":" (or "+:") as a refspec
520                  * for pushing matching refs.
521                  */
522                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
523                         rs[i].matching = 1;
524                         continue;
525                 }
526
527                 if (rhs) {
528                         size_t rlen = strlen(++rhs);
529                         is_glob = (1 <= rlen && strchr(rhs, '*'));
530                         rs[i].dst = xstrndup(rhs, rlen);
531                 }
532
533                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
534                 if (1 <= llen && memchr(lhs, '*', llen)) {
535                         if ((rhs && !is_glob) || (!rhs && fetch))
536                                 goto invalid;
537                         is_glob = 1;
538                 } else if (rhs && is_glob) {
539                         goto invalid;
540                 }
541
542                 rs[i].pattern = is_glob;
543                 rs[i].src = xstrndup(lhs, llen);
544                 flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
545
546                 if (fetch) {
547                         struct object_id unused;
548
549                         /* LHS */
550                         if (!*rs[i].src)
551                                 ; /* empty is ok; it means "HEAD" */
552                         else if (llen == GIT_SHA1_HEXSZ && !get_oid_hex(rs[i].src, &unused))
553                                 rs[i].exact_sha1 = 1; /* ok */
554                         else if (!check_refname_format(rs[i].src, flags))
555                                 ; /* valid looking ref is ok */
556                         else
557                                 goto invalid;
558                         /* RHS */
559                         if (!rs[i].dst)
560                                 ; /* missing is ok; it is the same as empty */
561                         else if (!*rs[i].dst)
562                                 ; /* empty is ok; it means "do not store" */
563                         else if (!check_refname_format(rs[i].dst, flags))
564                                 ; /* valid looking ref is ok */
565                         else
566                                 goto invalid;
567                 } else {
568                         /*
569                          * LHS
570                          * - empty is allowed; it means delete.
571                          * - when wildcarded, it must be a valid looking ref.
572                          * - otherwise, it must be an extended SHA-1, but
573                          *   there is no existing way to validate this.
574                          */
575                         if (!*rs[i].src)
576                                 ; /* empty is ok */
577                         else if (is_glob) {
578                                 if (check_refname_format(rs[i].src, flags))
579                                         goto invalid;
580                         }
581                         else
582                                 ; /* anything goes, for now */
583                         /*
584                          * RHS
585                          * - missing is allowed, but LHS then must be a
586                          *   valid looking ref.
587                          * - empty is not allowed.
588                          * - otherwise it must be a valid looking ref.
589                          */
590                         if (!rs[i].dst) {
591                                 if (check_refname_format(rs[i].src, flags))
592                                         goto invalid;
593                         } else if (!*rs[i].dst) {
594                                 goto invalid;
595                         } else {
596                                 if (check_refname_format(rs[i].dst, flags))
597                                         goto invalid;
598                         }
599                 }
600         }
601         return rs;
602
603  invalid:
604         if (verify) {
605                 /*
606                  * nr_refspec must be greater than zero and i must be valid
607                  * since it is only possible to reach this point from within
608                  * the for loop above.
609                  */
610                 free_refspecs(rs, i+1);
611                 return NULL;
612         }
613         die("Invalid refspec '%s'", refspec[i]);
614 }
615
616 int valid_fetch_refspec(const char *fetch_refspec_str)
617 {
618         struct refspec *refspec;
619
620         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
621         free_refspecs(refspec, 1);
622         return !!refspec;
623 }
624
625 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
626 {
627         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
628 }
629
630 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
631 {
632         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
633 }
634
635 void free_refspec(int nr_refspec, struct refspec *refspec)
636 {
637         int i;
638         for (i = 0; i < nr_refspec; i++) {
639                 free(refspec[i].src);
640                 free(refspec[i].dst);
641         }
642         free(refspec);
643 }
644
645 static int valid_remote_nick(const char *name)
646 {
647         if (!name[0] || is_dot_or_dotdot(name))
648                 return 0;
649         return !strchr(name, '/'); /* no slash */
650 }
651
652 const char *remote_for_branch(struct branch *branch, int *explicit)
653 {
654         if (branch && branch->remote_name) {
655                 if (explicit)
656                         *explicit = 1;
657                 return branch->remote_name;
658         }
659         if (explicit)
660                 *explicit = 0;
661         return "origin";
662 }
663
664 const char *pushremote_for_branch(struct branch *branch, int *explicit)
665 {
666         if (branch && branch->pushremote_name) {
667                 if (explicit)
668                         *explicit = 1;
669                 return branch->pushremote_name;
670         }
671         if (pushremote_name) {
672                 if (explicit)
673                         *explicit = 1;
674                 return pushremote_name;
675         }
676         return remote_for_branch(branch, explicit);
677 }
678
679 static struct remote *remote_get_1(const char *name,
680                                    const char *(*get_default)(struct branch *, int *))
681 {
682         struct remote *ret;
683         int name_given = 0;
684
685         read_config();
686
687         if (name)
688                 name_given = 1;
689         else
690                 name = get_default(current_branch, &name_given);
691
692         ret = make_remote(name, 0);
693         if (valid_remote_nick(name)) {
694                 if (!valid_remote(ret))
695                         read_remotes_file(ret);
696                 if (!valid_remote(ret))
697                         read_branches_file(ret);
698         }
699         if (name_given && !valid_remote(ret))
700                 add_url_alias(ret, name);
701         if (!valid_remote(ret))
702                 return NULL;
703         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
704         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
705         return ret;
706 }
707
708 struct remote *remote_get(const char *name)
709 {
710         return remote_get_1(name, remote_for_branch);
711 }
712
713 struct remote *pushremote_get(const char *name)
714 {
715         return remote_get_1(name, pushremote_for_branch);
716 }
717
718 int remote_is_configured(const char *name)
719 {
720         struct remotes_hash_key lookup;
721         struct hashmap_entry lookup_entry;
722         read_config();
723
724         init_remotes_hash();
725         lookup.str = name;
726         lookup.len = strlen(name);
727         hashmap_entry_init(&lookup_entry, memhash(name, lookup.len));
728
729         return hashmap_get(&remotes_hash, &lookup_entry, &lookup) != NULL;
730 }
731
732 int for_each_remote(each_remote_fn fn, void *priv)
733 {
734         int i, result = 0;
735         read_config();
736         for (i = 0; i < remotes_nr && !result; i++) {
737                 struct remote *r = remotes[i];
738                 if (!r)
739                         continue;
740                 if (!r->fetch)
741                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
742                                                        r->fetch_refspec);
743                 if (!r->push)
744                         r->push = parse_push_refspec(r->push_refspec_nr,
745                                                      r->push_refspec);
746                 result = fn(r, priv);
747         }
748         return result;
749 }
750
751 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
752 {
753         if (strcmp(ref1->name, ref2->name)) {
754                 if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
755                     ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
756                         die(_("Cannot fetch both %s and %s to %s"),
757                             ref1->name, ref2->name, ref2->peer_ref->name);
758                 } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
759                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
760                         warning(_("%s usually tracks %s, not %s"),
761                                 ref2->peer_ref->name, ref2->name, ref1->name);
762                 } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
763                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
764                         die(_("%s tracks both %s and %s"),
765                             ref2->peer_ref->name, ref1->name, ref2->name);
766                 } else {
767                         /*
768                          * This last possibility doesn't occur because
769                          * FETCH_HEAD_IGNORE entries always appear at
770                          * the end of the list.
771                          */
772                         die(_("Internal error"));
773                 }
774         }
775         free(ref2->peer_ref);
776         free(ref2);
777 }
778
779 struct ref *ref_remove_duplicates(struct ref *ref_map)
780 {
781         struct string_list refs = STRING_LIST_INIT_NODUP;
782         struct ref *retval = NULL;
783         struct ref **p = &retval;
784
785         while (ref_map) {
786                 struct ref *ref = ref_map;
787
788                 ref_map = ref_map->next;
789                 ref->next = NULL;
790
791                 if (!ref->peer_ref) {
792                         *p = ref;
793                         p = &ref->next;
794                 } else {
795                         struct string_list_item *item =
796                                 string_list_insert(&refs, ref->peer_ref->name);
797
798                         if (item->util) {
799                                 /* Entry already existed */
800                                 handle_duplicate((struct ref *)item->util, ref);
801                         } else {
802                                 *p = ref;
803                                 p = &ref->next;
804                                 item->util = ref;
805                         }
806                 }
807         }
808
809         string_list_clear(&refs, 0);
810         return retval;
811 }
812
813 int remote_has_url(struct remote *remote, const char *url)
814 {
815         int i;
816         for (i = 0; i < remote->url_nr; i++) {
817                 if (!strcmp(remote->url[i], url))
818                         return 1;
819         }
820         return 0;
821 }
822
823 static int match_name_with_pattern(const char *key, const char *name,
824                                    const char *value, char **result)
825 {
826         const char *kstar = strchr(key, '*');
827         size_t klen;
828         size_t ksuffixlen;
829         size_t namelen;
830         int ret;
831         if (!kstar)
832                 die("Key '%s' of pattern had no '*'", key);
833         klen = kstar - key;
834         ksuffixlen = strlen(kstar + 1);
835         namelen = strlen(name);
836         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
837                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
838         if (ret && value) {
839                 struct strbuf sb = STRBUF_INIT;
840                 const char *vstar = strchr(value, '*');
841                 if (!vstar)
842                         die("Value '%s' of pattern has no '*'", value);
843                 strbuf_add(&sb, value, vstar - value);
844                 strbuf_add(&sb, name + klen, namelen - klen - ksuffixlen);
845                 strbuf_addstr(&sb, vstar + 1);
846                 *result = strbuf_detach(&sb, NULL);
847         }
848         return ret;
849 }
850
851 static void query_refspecs_multiple(struct refspec *refs, int ref_count, struct refspec *query, struct string_list *results)
852 {
853         int i;
854         int find_src = !query->src;
855
856         if (find_src && !query->dst)
857                 error("query_refspecs_multiple: need either src or dst");
858
859         for (i = 0; i < ref_count; i++) {
860                 struct refspec *refspec = &refs[i];
861                 const char *key = find_src ? refspec->dst : refspec->src;
862                 const char *value = find_src ? refspec->src : refspec->dst;
863                 const char *needle = find_src ? query->dst : query->src;
864                 char **result = find_src ? &query->src : &query->dst;
865
866                 if (!refspec->dst)
867                         continue;
868                 if (refspec->pattern) {
869                         if (match_name_with_pattern(key, needle, value, result))
870                                 string_list_append_nodup(results, *result);
871                 } else if (!strcmp(needle, key)) {
872                         string_list_append(results, value);
873                 }
874         }
875 }
876
877 int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
878 {
879         int i;
880         int find_src = !query->src;
881         const char *needle = find_src ? query->dst : query->src;
882         char **result = find_src ? &query->src : &query->dst;
883
884         if (find_src && !query->dst)
885                 return error("query_refspecs: need either src or dst");
886
887         for (i = 0; i < ref_count; i++) {
888                 struct refspec *refspec = &refs[i];
889                 const char *key = find_src ? refspec->dst : refspec->src;
890                 const char *value = find_src ? refspec->src : refspec->dst;
891
892                 if (!refspec->dst)
893                         continue;
894                 if (refspec->pattern) {
895                         if (match_name_with_pattern(key, needle, value, result)) {
896                                 query->force = refspec->force;
897                                 return 0;
898                         }
899                 } else if (!strcmp(needle, key)) {
900                         *result = xstrdup(value);
901                         query->force = refspec->force;
902                         return 0;
903                 }
904         }
905         return -1;
906 }
907
908 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
909                      const char *name)
910 {
911         struct refspec query;
912
913         memset(&query, 0, sizeof(struct refspec));
914         query.src = (char *)name;
915
916         if (query_refspecs(refspecs, nr_refspec, &query))
917                 return NULL;
918
919         return query.dst;
920 }
921
922 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
923 {
924         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
925 }
926
927 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
928                 const char *name)
929 {
930         size_t len = strlen(name);
931         struct ref *ref = xcalloc(1, st_add4(sizeof(*ref), prefixlen, len, 1));
932         memcpy(ref->name, prefix, prefixlen);
933         memcpy(ref->name + prefixlen, name, len);
934         return ref;
935 }
936
937 struct ref *alloc_ref(const char *name)
938 {
939         return alloc_ref_with_prefix("", 0, name);
940 }
941
942 struct ref *copy_ref(const struct ref *ref)
943 {
944         struct ref *cpy;
945         size_t len;
946         if (!ref)
947                 return NULL;
948         len = st_add3(sizeof(struct ref), strlen(ref->name), 1);
949         cpy = xmalloc(len);
950         memcpy(cpy, ref, len);
951         cpy->next = NULL;
952         cpy->symref = xstrdup_or_null(ref->symref);
953         cpy->remote_status = xstrdup_or_null(ref->remote_status);
954         cpy->peer_ref = copy_ref(ref->peer_ref);
955         return cpy;
956 }
957
958 struct ref *copy_ref_list(const struct ref *ref)
959 {
960         struct ref *ret = NULL;
961         struct ref **tail = &ret;
962         while (ref) {
963                 *tail = copy_ref(ref);
964                 ref = ref->next;
965                 tail = &((*tail)->next);
966         }
967         return ret;
968 }
969
970 static void free_ref(struct ref *ref)
971 {
972         if (!ref)
973                 return;
974         free_ref(ref->peer_ref);
975         free(ref->remote_status);
976         free(ref->symref);
977         free(ref);
978 }
979
980 void free_refs(struct ref *ref)
981 {
982         struct ref *next;
983         while (ref) {
984                 next = ref->next;
985                 free_ref(ref);
986                 ref = next;
987         }
988 }
989
990 int ref_compare_name(const void *va, const void *vb)
991 {
992         const struct ref *a = va, *b = vb;
993         return strcmp(a->name, b->name);
994 }
995
996 static void *ref_list_get_next(const void *a)
997 {
998         return ((const struct ref *)a)->next;
999 }
1000
1001 static void ref_list_set_next(void *a, void *next)
1002 {
1003         ((struct ref *)a)->next = next;
1004 }
1005
1006 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
1007 {
1008         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
1009 }
1010
1011 int count_refspec_match(const char *pattern,
1012                         struct ref *refs,
1013                         struct ref **matched_ref)
1014 {
1015         int patlen = strlen(pattern);
1016         struct ref *matched_weak = NULL;
1017         struct ref *matched = NULL;
1018         int weak_match = 0;
1019         int match = 0;
1020
1021         for (weak_match = match = 0; refs; refs = refs->next) {
1022                 char *name = refs->name;
1023                 int namelen = strlen(name);
1024
1025                 if (!refname_match(pattern, name))
1026                         continue;
1027
1028                 /* A match is "weak" if it is with refs outside
1029                  * heads or tags, and did not specify the pattern
1030                  * in full (e.g. "refs/remotes/origin/master") or at
1031                  * least from the toplevel (e.g. "remotes/origin/master");
1032                  * otherwise "git push $URL master" would result in
1033                  * ambiguity between remotes/origin/master and heads/master
1034                  * at the remote site.
1035                  */
1036                 if (namelen != patlen &&
1037                     patlen != namelen - 5 &&
1038                     !starts_with(name, "refs/heads/") &&
1039                     !starts_with(name, "refs/tags/")) {
1040                         /* We want to catch the case where only weak
1041                          * matches are found and there are multiple
1042                          * matches, and where more than one strong
1043                          * matches are found, as ambiguous.  One
1044                          * strong match with zero or more weak matches
1045                          * are acceptable as a unique match.
1046                          */
1047                         matched_weak = refs;
1048                         weak_match++;
1049                 }
1050                 else {
1051                         matched = refs;
1052                         match++;
1053                 }
1054         }
1055         if (!matched) {
1056                 if (matched_ref)
1057                         *matched_ref = matched_weak;
1058                 return weak_match;
1059         }
1060         else {
1061                 if (matched_ref)
1062                         *matched_ref = matched;
1063                 return match;
1064         }
1065 }
1066
1067 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1068 {
1069         **tail = ref;
1070         while (ref->next)
1071                 ref = ref->next;
1072         *tail = &ref->next;
1073 }
1074
1075 static struct ref *alloc_delete_ref(void)
1076 {
1077         struct ref *ref = alloc_ref("(delete)");
1078         oidclr(&ref->new_oid);
1079         return ref;
1080 }
1081
1082 static int try_explicit_object_name(const char *name,
1083                                     struct ref **match)
1084 {
1085         struct object_id oid;
1086
1087         if (!*name) {
1088                 if (match)
1089                         *match = alloc_delete_ref();
1090                 return 0;
1091         }
1092
1093         if (get_sha1(name, oid.hash))
1094                 return -1;
1095
1096         if (match) {
1097                 *match = alloc_ref(name);
1098                 oidcpy(&(*match)->new_oid, &oid);
1099         }
1100         return 0;
1101 }
1102
1103 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1104 {
1105         struct ref *ret = alloc_ref(name);
1106         tail_link_ref(ret, tail);
1107         return ret;
1108 }
1109
1110 static char *guess_ref(const char *name, struct ref *peer)
1111 {
1112         struct strbuf buf = STRBUF_INIT;
1113         struct object_id oid;
1114
1115         const char *r = resolve_ref_unsafe(peer->name, RESOLVE_REF_READING,
1116                                            oid.hash, NULL);
1117         if (!r)
1118                 return NULL;
1119
1120         if (starts_with(r, "refs/heads/"))
1121                 strbuf_addstr(&buf, "refs/heads/");
1122         else if (starts_with(r, "refs/tags/"))
1123                 strbuf_addstr(&buf, "refs/tags/");
1124         else
1125                 return NULL;
1126
1127         strbuf_addstr(&buf, name);
1128         return strbuf_detach(&buf, NULL);
1129 }
1130
1131 static int match_explicit_lhs(struct ref *src,
1132                               struct refspec *rs,
1133                               struct ref **match,
1134                               int *allocated_match)
1135 {
1136         switch (count_refspec_match(rs->src, src, match)) {
1137         case 1:
1138                 if (allocated_match)
1139                         *allocated_match = 0;
1140                 return 0;
1141         case 0:
1142                 /* The source could be in the get_sha1() format
1143                  * not a reference name.  :refs/other is a
1144                  * way to delete 'other' ref at the remote end.
1145                  */
1146                 if (try_explicit_object_name(rs->src, match) < 0)
1147                         return error("src refspec %s does not match any.", rs->src);
1148                 if (allocated_match)
1149                         *allocated_match = 1;
1150                 return 0;
1151         default:
1152                 return error("src refspec %s matches more than one.", rs->src);
1153         }
1154 }
1155
1156 static int match_explicit(struct ref *src, struct ref *dst,
1157                           struct ref ***dst_tail,
1158                           struct refspec *rs)
1159 {
1160         struct ref *matched_src, *matched_dst;
1161         int allocated_src;
1162
1163         const char *dst_value = rs->dst;
1164         char *dst_guess;
1165
1166         if (rs->pattern || rs->matching)
1167                 return 0;
1168
1169         matched_src = matched_dst = NULL;
1170         if (match_explicit_lhs(src, rs, &matched_src, &allocated_src) < 0)
1171                 return -1;
1172
1173         if (!dst_value) {
1174                 struct object_id oid;
1175                 int flag;
1176
1177                 dst_value = resolve_ref_unsafe(matched_src->name,
1178                                                RESOLVE_REF_READING,
1179                                                oid.hash, &flag);
1180                 if (!dst_value ||
1181                     ((flag & REF_ISSYMREF) &&
1182                      !starts_with(dst_value, "refs/heads/")))
1183                         die("%s cannot be resolved to branch.",
1184                             matched_src->name);
1185         }
1186
1187         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1188         case 1:
1189                 break;
1190         case 0:
1191                 if (starts_with(dst_value, "refs/"))
1192                         matched_dst = make_linked_ref(dst_value, dst_tail);
1193                 else if (is_null_oid(&matched_src->new_oid))
1194                         error("unable to delete '%s': remote ref does not exist",
1195                               dst_value);
1196                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1197                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1198                 else
1199                         error("unable to push to unqualified destination: %s\n"
1200                               "The destination refspec neither matches an "
1201                               "existing ref on the remote nor\n"
1202                               "begins with refs/, and we are unable to "
1203                               "guess a prefix based on the source ref.",
1204                               dst_value);
1205                 break;
1206         default:
1207                 matched_dst = NULL;
1208                 error("dst refspec %s matches more than one.",
1209                       dst_value);
1210                 break;
1211         }
1212         if (!matched_dst)
1213                 return -1;
1214         if (matched_dst->peer_ref)
1215                 return error("dst ref %s receives from more than one src.",
1216                       matched_dst->name);
1217         else {
1218                 matched_dst->peer_ref = allocated_src ?
1219                                         matched_src :
1220                                         copy_ref(matched_src);
1221                 matched_dst->force = rs->force;
1222         }
1223         return 0;
1224 }
1225
1226 static int match_explicit_refs(struct ref *src, struct ref *dst,
1227                                struct ref ***dst_tail, struct refspec *rs,
1228                                int rs_nr)
1229 {
1230         int i, errs;
1231         for (i = errs = 0; i < rs_nr; i++)
1232                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1233         return errs;
1234 }
1235
1236 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1237                 int send_mirror, int direction, const struct refspec **ret_pat)
1238 {
1239         const struct refspec *pat;
1240         char *name;
1241         int i;
1242         int matching_refs = -1;
1243         for (i = 0; i < rs_nr; i++) {
1244                 if (rs[i].matching &&
1245                     (matching_refs == -1 || rs[i].force)) {
1246                         matching_refs = i;
1247                         continue;
1248                 }
1249
1250                 if (rs[i].pattern) {
1251                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1252                         int match;
1253                         if (direction == FROM_SRC)
1254                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1255                         else
1256                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1257                         if (match) {
1258                                 matching_refs = i;
1259                                 break;
1260                         }
1261                 }
1262         }
1263         if (matching_refs == -1)
1264                 return NULL;
1265
1266         pat = rs + matching_refs;
1267         if (pat->matching) {
1268                 /*
1269                  * "matching refs"; traditionally we pushed everything
1270                  * including refs outside refs/heads/ hierarchy, but
1271                  * that does not make much sense these days.
1272                  */
1273                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1274                         return NULL;
1275                 name = xstrdup(ref->name);
1276         }
1277         if (ret_pat)
1278                 *ret_pat = pat;
1279         return name;
1280 }
1281
1282 static struct ref **tail_ref(struct ref **head)
1283 {
1284         struct ref **tail = head;
1285         while (*tail)
1286                 tail = &((*tail)->next);
1287         return tail;
1288 }
1289
1290 struct tips {
1291         struct commit **tip;
1292         int nr, alloc;
1293 };
1294
1295 static void add_to_tips(struct tips *tips, const struct object_id *oid)
1296 {
1297         struct commit *commit;
1298
1299         if (is_null_oid(oid))
1300                 return;
1301         commit = lookup_commit_reference_gently(oid->hash, 1);
1302         if (!commit || (commit->object.flags & TMP_MARK))
1303                 return;
1304         commit->object.flags |= TMP_MARK;
1305         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1306         tips->tip[tips->nr++] = commit;
1307 }
1308
1309 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1310 {
1311         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1312         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1313         struct string_list_item *item;
1314         struct ref *ref;
1315         struct tips sent_tips;
1316
1317         /*
1318          * Collect everything we know they would have at the end of
1319          * this push, and collect all tags they have.
1320          */
1321         memset(&sent_tips, 0, sizeof(sent_tips));
1322         for (ref = *dst; ref; ref = ref->next) {
1323                 if (ref->peer_ref &&
1324                     !is_null_oid(&ref->peer_ref->new_oid))
1325                         add_to_tips(&sent_tips, &ref->peer_ref->new_oid);
1326                 else
1327                         add_to_tips(&sent_tips, &ref->old_oid);
1328                 if (starts_with(ref->name, "refs/tags/"))
1329                         string_list_append(&dst_tag, ref->name);
1330         }
1331         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1332
1333         string_list_sort(&dst_tag);
1334
1335         /* Collect tags they do not have. */
1336         for (ref = src; ref; ref = ref->next) {
1337                 if (!starts_with(ref->name, "refs/tags/"))
1338                         continue; /* not a tag */
1339                 if (string_list_has_string(&dst_tag, ref->name))
1340                         continue; /* they already have it */
1341                 if (sha1_object_info(ref->new_oid.hash, NULL) != OBJ_TAG)
1342                         continue; /* be conservative */
1343                 item = string_list_append(&src_tag, ref->name);
1344                 item->util = ref;
1345         }
1346         string_list_clear(&dst_tag, 0);
1347
1348         /*
1349          * At this point, src_tag lists tags that are missing from
1350          * dst, and sent_tips lists the tips we are pushing or those
1351          * that we know they already have. An element in the src_tag
1352          * that is an ancestor of any of the sent_tips needs to be
1353          * sent to the other side.
1354          */
1355         if (sent_tips.nr) {
1356                 for_each_string_list_item(item, &src_tag) {
1357                         struct ref *ref = item->util;
1358                         struct ref *dst_ref;
1359                         struct commit *commit;
1360
1361                         if (is_null_oid(&ref->new_oid))
1362                                 continue;
1363                         commit = lookup_commit_reference_gently(ref->new_oid.hash, 1);
1364                         if (!commit)
1365                                 /* not pushing a commit, which is not an error */
1366                                 continue;
1367
1368                         /*
1369                          * Is this tag, which they do not have, reachable from
1370                          * any of the commits we are sending?
1371                          */
1372                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1373                                 continue;
1374
1375                         /* Add it in */
1376                         dst_ref = make_linked_ref(ref->name, dst_tail);
1377                         oidcpy(&dst_ref->new_oid, &ref->new_oid);
1378                         dst_ref->peer_ref = copy_ref(ref);
1379                 }
1380         }
1381         string_list_clear(&src_tag, 0);
1382         free(sent_tips.tip);
1383 }
1384
1385 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1386 {
1387         for ( ; list; list = list->next)
1388                 if (!strcmp(list->name, name))
1389                         return (struct ref *)list;
1390         return NULL;
1391 }
1392
1393 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1394 {
1395         for ( ; ref; ref = ref->next)
1396                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1397
1398         string_list_sort(ref_index);
1399 }
1400
1401 /*
1402  * Given only the set of local refs, sanity-check the set of push
1403  * refspecs. We can't catch all errors that match_push_refs would,
1404  * but we can catch some errors early before even talking to the
1405  * remote side.
1406  */
1407 int check_push_refs(struct ref *src, int nr_refspec, const char **refspec_names)
1408 {
1409         struct refspec *refspec = parse_push_refspec(nr_refspec, refspec_names);
1410         int ret = 0;
1411         int i;
1412
1413         for (i = 0; i < nr_refspec; i++) {
1414                 struct refspec *rs = refspec + i;
1415
1416                 if (rs->pattern || rs->matching)
1417                         continue;
1418
1419                 ret |= match_explicit_lhs(src, rs, NULL, NULL);
1420         }
1421
1422         free_refspec(nr_refspec, refspec);
1423         return ret;
1424 }
1425
1426 /*
1427  * Given the set of refs the local repository has, the set of refs the
1428  * remote repository has, and the refspec used for push, determine
1429  * what remote refs we will update and with what value by setting
1430  * peer_ref (which object is being pushed) and force (if the push is
1431  * forced) in elements of "dst". The function may add new elements to
1432  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1433  */
1434 int match_push_refs(struct ref *src, struct ref **dst,
1435                     int nr_refspec, const char **refspec, int flags)
1436 {
1437         struct refspec *rs;
1438         int send_all = flags & MATCH_REFS_ALL;
1439         int send_mirror = flags & MATCH_REFS_MIRROR;
1440         int send_prune = flags & MATCH_REFS_PRUNE;
1441         int errs;
1442         static const char *default_refspec[] = { ":", NULL };
1443         struct ref *ref, **dst_tail = tail_ref(dst);
1444         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1445
1446         if (!nr_refspec) {
1447                 nr_refspec = 1;
1448                 refspec = default_refspec;
1449         }
1450         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1451         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1452
1453         /* pick the remainder */
1454         for (ref = src; ref; ref = ref->next) {
1455                 struct string_list_item *dst_item;
1456                 struct ref *dst_peer;
1457                 const struct refspec *pat = NULL;
1458                 char *dst_name;
1459
1460                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1461                 if (!dst_name)
1462                         continue;
1463
1464                 if (!dst_ref_index.nr)
1465                         prepare_ref_index(&dst_ref_index, *dst);
1466
1467                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1468                 dst_peer = dst_item ? dst_item->util : NULL;
1469                 if (dst_peer) {
1470                         if (dst_peer->peer_ref)
1471                                 /* We're already sending something to this ref. */
1472                                 goto free_name;
1473                 } else {
1474                         if (pat->matching && !(send_all || send_mirror))
1475                                 /*
1476                                  * Remote doesn't have it, and we have no
1477                                  * explicit pattern, and we don't have
1478                                  * --all or --mirror.
1479                                  */
1480                                 goto free_name;
1481
1482                         /* Create a new one and link it */
1483                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1484                         oidcpy(&dst_peer->new_oid, &ref->new_oid);
1485                         string_list_insert(&dst_ref_index,
1486                                 dst_peer->name)->util = dst_peer;
1487                 }
1488                 dst_peer->peer_ref = copy_ref(ref);
1489                 dst_peer->force = pat->force;
1490         free_name:
1491                 free(dst_name);
1492         }
1493
1494         string_list_clear(&dst_ref_index, 0);
1495
1496         if (flags & MATCH_REFS_FOLLOW_TAGS)
1497                 add_missing_tags(src, dst, &dst_tail);
1498
1499         if (send_prune) {
1500                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1501                 /* check for missing refs on the remote */
1502                 for (ref = *dst; ref; ref = ref->next) {
1503                         char *src_name;
1504
1505                         if (ref->peer_ref)
1506                                 /* We're already sending something to this ref. */
1507                                 continue;
1508
1509                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1510                         if (src_name) {
1511                                 if (!src_ref_index.nr)
1512                                         prepare_ref_index(&src_ref_index, src);
1513                                 if (!string_list_has_string(&src_ref_index,
1514                                             src_name))
1515                                         ref->peer_ref = alloc_delete_ref();
1516                                 free(src_name);
1517                         }
1518                 }
1519                 string_list_clear(&src_ref_index, 0);
1520         }
1521         if (errs)
1522                 return -1;
1523         return 0;
1524 }
1525
1526 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1527                              int force_update)
1528 {
1529         struct ref *ref;
1530
1531         for (ref = remote_refs; ref; ref = ref->next) {
1532                 int force_ref_update = ref->force || force_update;
1533                 int reject_reason = 0;
1534
1535                 if (ref->peer_ref)
1536                         oidcpy(&ref->new_oid, &ref->peer_ref->new_oid);
1537                 else if (!send_mirror)
1538                         continue;
1539
1540                 ref->deletion = is_null_oid(&ref->new_oid);
1541                 if (!ref->deletion &&
1542                         !oidcmp(&ref->old_oid, &ref->new_oid)) {
1543                         ref->status = REF_STATUS_UPTODATE;
1544                         continue;
1545                 }
1546
1547                 /*
1548                  * If the remote ref has moved and is now different
1549                  * from what we expect, reject any push.
1550                  *
1551                  * It also is an error if the user told us to check
1552                  * with the remote-tracking branch to find the value
1553                  * to expect, but we did not have such a tracking
1554                  * branch.
1555                  */
1556                 if (ref->expect_old_sha1) {
1557                         if (ref->expect_old_no_trackback ||
1558                             oidcmp(&ref->old_oid, &ref->old_oid_expect))
1559                                 reject_reason = REF_STATUS_REJECT_STALE;
1560                         else
1561                                 /* If the ref isn't stale then force the update. */
1562                                 force_ref_update = 1;
1563                 }
1564
1565                 /*
1566                  * If the update isn't already rejected then check
1567                  * the usual "must fast-forward" rules.
1568                  *
1569                  * Decide whether an individual refspec A:B can be
1570                  * pushed.  The push will succeed if any of the
1571                  * following are true:
1572                  *
1573                  * (1) the remote reference B does not exist
1574                  *
1575                  * (2) the remote reference B is being removed (i.e.,
1576                  *     pushing :B where no source is specified)
1577                  *
1578                  * (3) the destination is not under refs/tags/, and
1579                  *     if the old and new value is a commit, the new
1580                  *     is a descendant of the old.
1581                  *
1582                  * (4) it is forced using the +A:B notation, or by
1583                  *     passing the --force argument
1584                  */
1585
1586                 if (!reject_reason && !ref->deletion && !is_null_oid(&ref->old_oid)) {
1587                         if (starts_with(ref->name, "refs/tags/"))
1588                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1589                         else if (!has_object_file(&ref->old_oid))
1590                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1591                         else if (!lookup_commit_reference_gently(ref->old_oid.hash, 1) ||
1592                                  !lookup_commit_reference_gently(ref->new_oid.hash, 1))
1593                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1594                         else if (!ref_newer(&ref->new_oid, &ref->old_oid))
1595                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1596                 }
1597
1598                 /*
1599                  * "--force" will defeat any rejection implemented
1600                  * by the rules above.
1601                  */
1602                 if (!force_ref_update)
1603                         ref->status = reject_reason;
1604                 else if (reject_reason)
1605                         ref->forced_update = 1;
1606         }
1607 }
1608
1609 static void set_merge(struct branch *ret)
1610 {
1611         struct remote *remote;
1612         char *ref;
1613         struct object_id oid;
1614         int i;
1615
1616         if (!ret)
1617                 return; /* no branch */
1618         if (ret->merge)
1619                 return; /* already run */
1620         if (!ret->remote_name || !ret->merge_nr) {
1621                 /*
1622                  * no merge config; let's make sure we don't confuse callers
1623                  * with a non-zero merge_nr but a NULL merge
1624                  */
1625                 ret->merge_nr = 0;
1626                 return;
1627         }
1628
1629         remote = remote_get(ret->remote_name);
1630
1631         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1632         for (i = 0; i < ret->merge_nr; i++) {
1633                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1634                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1635                 if (!remote_find_tracking(remote, ret->merge[i]) ||
1636                     strcmp(ret->remote_name, "."))
1637                         continue;
1638                 if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
1639                              oid.hash, &ref) == 1)
1640                         ret->merge[i]->dst = ref;
1641                 else
1642                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1643         }
1644 }
1645
1646 struct branch *branch_get(const char *name)
1647 {
1648         struct branch *ret;
1649
1650         read_config();
1651         if (!name || !*name || !strcmp(name, "HEAD"))
1652                 ret = current_branch;
1653         else
1654                 ret = make_branch(name, 0);
1655         set_merge(ret);
1656         return ret;
1657 }
1658
1659 int branch_has_merge_config(struct branch *branch)
1660 {
1661         return branch && !!branch->merge;
1662 }
1663
1664 int branch_merge_matches(struct branch *branch,
1665                                  int i,
1666                                  const char *refname)
1667 {
1668         if (!branch || i < 0 || i >= branch->merge_nr)
1669                 return 0;
1670         return refname_match(branch->merge[i]->src, refname);
1671 }
1672
1673 __attribute((format (printf,2,3)))
1674 static const char *error_buf(struct strbuf *err, const char *fmt, ...)
1675 {
1676         if (err) {
1677                 va_list ap;
1678                 va_start(ap, fmt);
1679                 strbuf_vaddf(err, fmt, ap);
1680                 va_end(ap);
1681         }
1682         return NULL;
1683 }
1684
1685 const char *branch_get_upstream(struct branch *branch, struct strbuf *err)
1686 {
1687         if (!branch)
1688                 return error_buf(err, _("HEAD does not point to a branch"));
1689
1690         if (!branch->merge || !branch->merge[0]) {
1691                 /*
1692                  * no merge config; is it because the user didn't define any,
1693                  * or because it is not a real branch, and get_branch
1694                  * auto-vivified it?
1695                  */
1696                 if (!ref_exists(branch->refname))
1697                         return error_buf(err, _("no such branch: '%s'"),
1698                                          branch->name);
1699                 return error_buf(err,
1700                                  _("no upstream configured for branch '%s'"),
1701                                  branch->name);
1702         }
1703
1704         if (!branch->merge[0]->dst)
1705                 return error_buf(err,
1706                                  _("upstream branch '%s' not stored as a remote-tracking branch"),
1707                                  branch->merge[0]->src);
1708
1709         return branch->merge[0]->dst;
1710 }
1711
1712 static const char *tracking_for_push_dest(struct remote *remote,
1713                                           const char *refname,
1714                                           struct strbuf *err)
1715 {
1716         char *ret;
1717
1718         ret = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
1719         if (!ret)
1720                 return error_buf(err,
1721                                  _("push destination '%s' on remote '%s' has no local tracking branch"),
1722                                  refname, remote->name);
1723         return ret;
1724 }
1725
1726 static const char *branch_get_push_1(struct branch *branch, struct strbuf *err)
1727 {
1728         struct remote *remote;
1729
1730         if (!branch)
1731                 return error_buf(err, _("HEAD does not point to a branch"));
1732
1733         remote = remote_get(pushremote_for_branch(branch, NULL));
1734         if (!remote)
1735                 return error_buf(err,
1736                                  _("branch '%s' has no remote for pushing"),
1737                                  branch->name);
1738
1739         if (remote->push_refspec_nr) {
1740                 char *dst;
1741                 const char *ret;
1742
1743                 dst = apply_refspecs(remote->push, remote->push_refspec_nr,
1744                                      branch->refname);
1745                 if (!dst)
1746                         return error_buf(err,
1747                                          _("push refspecs for '%s' do not include '%s'"),
1748                                          remote->name, branch->name);
1749
1750                 ret = tracking_for_push_dest(remote, dst, err);
1751                 free(dst);
1752                 return ret;
1753         }
1754
1755         if (remote->mirror)
1756                 return tracking_for_push_dest(remote, branch->refname, err);
1757
1758         switch (push_default) {
1759         case PUSH_DEFAULT_NOTHING:
1760                 return error_buf(err, _("push has no destination (push.default is 'nothing')"));
1761
1762         case PUSH_DEFAULT_MATCHING:
1763         case PUSH_DEFAULT_CURRENT:
1764                 return tracking_for_push_dest(remote, branch->refname, err);
1765
1766         case PUSH_DEFAULT_UPSTREAM:
1767                 return branch_get_upstream(branch, err);
1768
1769         case PUSH_DEFAULT_UNSPECIFIED:
1770         case PUSH_DEFAULT_SIMPLE:
1771                 {
1772                         const char *up, *cur;
1773
1774                         up = branch_get_upstream(branch, err);
1775                         if (!up)
1776                                 return NULL;
1777                         cur = tracking_for_push_dest(remote, branch->refname, err);
1778                         if (!cur)
1779                                 return NULL;
1780                         if (strcmp(cur, up))
1781                                 return error_buf(err,
1782                                                  _("cannot resolve 'simple' push to a single destination"));
1783                         return cur;
1784                 }
1785         }
1786
1787         die("BUG: unhandled push situation");
1788 }
1789
1790 const char *branch_get_push(struct branch *branch, struct strbuf *err)
1791 {
1792         if (!branch->push_tracking_ref)
1793                 branch->push_tracking_ref = branch_get_push_1(branch, err);
1794         return branch->push_tracking_ref;
1795 }
1796
1797 static int ignore_symref_update(const char *refname)
1798 {
1799         struct object_id oid;
1800         int flag;
1801
1802         if (!resolve_ref_unsafe(refname, 0, oid.hash, &flag))
1803                 return 0; /* non-existing refs are OK */
1804         return (flag & REF_ISSYMREF);
1805 }
1806
1807 /*
1808  * Create and return a list of (struct ref) consisting of copies of
1809  * each remote_ref that matches refspec.  refspec must be a pattern.
1810  * Fill in the copies' peer_ref to describe the local tracking refs to
1811  * which they map.  Omit any references that would map to an existing
1812  * local symbolic ref.
1813  */
1814 static struct ref *get_expanded_map(const struct ref *remote_refs,
1815                                     const struct refspec *refspec)
1816 {
1817         const struct ref *ref;
1818         struct ref *ret = NULL;
1819         struct ref **tail = &ret;
1820
1821         for (ref = remote_refs; ref; ref = ref->next) {
1822                 char *expn_name = NULL;
1823
1824                 if (strchr(ref->name, '^'))
1825                         continue; /* a dereference item */
1826                 if (match_name_with_pattern(refspec->src, ref->name,
1827                                             refspec->dst, &expn_name) &&
1828                     !ignore_symref_update(expn_name)) {
1829                         struct ref *cpy = copy_ref(ref);
1830
1831                         cpy->peer_ref = alloc_ref(expn_name);
1832                         if (refspec->force)
1833                                 cpy->peer_ref->force = 1;
1834                         *tail = cpy;
1835                         tail = &cpy->next;
1836                 }
1837                 free(expn_name);
1838         }
1839
1840         return ret;
1841 }
1842
1843 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1844 {
1845         const struct ref *ref;
1846         for (ref = refs; ref; ref = ref->next) {
1847                 if (refname_match(name, ref->name))
1848                         return ref;
1849         }
1850         return NULL;
1851 }
1852
1853 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1854 {
1855         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1856
1857         if (!ref)
1858                 return NULL;
1859
1860         return copy_ref(ref);
1861 }
1862
1863 static struct ref *get_local_ref(const char *name)
1864 {
1865         if (!name || name[0] == '\0')
1866                 return NULL;
1867
1868         if (starts_with(name, "refs/"))
1869                 return alloc_ref(name);
1870
1871         if (starts_with(name, "heads/") ||
1872             starts_with(name, "tags/") ||
1873             starts_with(name, "remotes/"))
1874                 return alloc_ref_with_prefix("refs/", 5, name);
1875
1876         return alloc_ref_with_prefix("refs/heads/", 11, name);
1877 }
1878
1879 int get_fetch_map(const struct ref *remote_refs,
1880                   const struct refspec *refspec,
1881                   struct ref ***tail,
1882                   int missing_ok)
1883 {
1884         struct ref *ref_map, **rmp;
1885
1886         if (refspec->pattern) {
1887                 ref_map = get_expanded_map(remote_refs, refspec);
1888         } else {
1889                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1890
1891                 if (refspec->exact_sha1) {
1892                         ref_map = alloc_ref(name);
1893                         get_oid_hex(name, &ref_map->old_oid);
1894                 } else {
1895                         ref_map = get_remote_ref(remote_refs, name);
1896                 }
1897                 if (!missing_ok && !ref_map)
1898                         die("Couldn't find remote ref %s", name);
1899                 if (ref_map) {
1900                         ref_map->peer_ref = get_local_ref(refspec->dst);
1901                         if (ref_map->peer_ref && refspec->force)
1902                                 ref_map->peer_ref->force = 1;
1903                 }
1904         }
1905
1906         for (rmp = &ref_map; *rmp; ) {
1907                 if ((*rmp)->peer_ref) {
1908                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1909                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1910                                 struct ref *ignore = *rmp;
1911                                 error("* Ignoring funny ref '%s' locally",
1912                                       (*rmp)->peer_ref->name);
1913                                 *rmp = (*rmp)->next;
1914                                 free(ignore->peer_ref);
1915                                 free(ignore);
1916                                 continue;
1917                         }
1918                 }
1919                 rmp = &((*rmp)->next);
1920         }
1921
1922         if (ref_map)
1923                 tail_link_ref(ref_map, tail);
1924
1925         return 0;
1926 }
1927
1928 int resolve_remote_symref(struct ref *ref, struct ref *list)
1929 {
1930         if (!ref->symref)
1931                 return 0;
1932         for (; list; list = list->next)
1933                 if (!strcmp(ref->symref, list->name)) {
1934                         oidcpy(&ref->old_oid, &list->old_oid);
1935                         return 0;
1936                 }
1937         return 1;
1938 }
1939
1940 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1941 {
1942         while (list) {
1943                 struct commit *commit = pop_commit(&list);
1944                 commit->object.flags &= ~mark;
1945         }
1946 }
1947
1948 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
1949 {
1950         struct object *o;
1951         struct commit *old, *new;
1952         struct commit_list *list, *used;
1953         int found = 0;
1954
1955         /*
1956          * Both new and old must be commit-ish and new is descendant of
1957          * old.  Otherwise we require --force.
1958          */
1959         o = deref_tag(parse_object(old_oid->hash), NULL, 0);
1960         if (!o || o->type != OBJ_COMMIT)
1961                 return 0;
1962         old = (struct commit *) o;
1963
1964         o = deref_tag(parse_object(new_oid->hash), NULL, 0);
1965         if (!o || o->type != OBJ_COMMIT)
1966                 return 0;
1967         new = (struct commit *) o;
1968
1969         if (parse_commit(new) < 0)
1970                 return 0;
1971
1972         used = list = NULL;
1973         commit_list_insert(new, &list);
1974         while (list) {
1975                 new = pop_most_recent_commit(&list, TMP_MARK);
1976                 commit_list_insert(new, &used);
1977                 if (new == old) {
1978                         found = 1;
1979                         break;
1980                 }
1981         }
1982         unmark_and_free(list, TMP_MARK);
1983         unmark_and_free(used, TMP_MARK);
1984         return found;
1985 }
1986
1987 /*
1988  * Compare a branch with its upstream, and save their differences (number
1989  * of commits) in *num_ours and *num_theirs. The name of the upstream branch
1990  * (or NULL if no upstream is defined) is returned via *upstream_name, if it
1991  * is not itself NULL.
1992  *
1993  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
1994  * upstream defined, or ref does not exist), 0 otherwise.
1995  */
1996 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
1997                        const char **upstream_name)
1998 {
1999         struct object_id oid;
2000         struct commit *ours, *theirs;
2001         struct rev_info revs;
2002         const char *base;
2003         struct argv_array argv = ARGV_ARRAY_INIT;
2004
2005         /* Cannot stat unless we are marked to build on top of somebody else. */
2006         base = branch_get_upstream(branch, NULL);
2007         if (upstream_name)
2008                 *upstream_name = base;
2009         if (!base)
2010                 return -1;
2011
2012         /* Cannot stat if what we used to build on no longer exists */
2013         if (read_ref(base, oid.hash))
2014                 return -1;
2015         theirs = lookup_commit_reference(oid.hash);
2016         if (!theirs)
2017                 return -1;
2018
2019         if (read_ref(branch->refname, oid.hash))
2020                 return -1;
2021         ours = lookup_commit_reference(oid.hash);
2022         if (!ours)
2023                 return -1;
2024
2025         /* are we the same? */
2026         if (theirs == ours) {
2027                 *num_theirs = *num_ours = 0;
2028                 return 0;
2029         }
2030
2031         /* Run "rev-list --left-right ours...theirs" internally... */
2032         argv_array_push(&argv, ""); /* ignored */
2033         argv_array_push(&argv, "--left-right");
2034         argv_array_pushf(&argv, "%s...%s",
2035                          oid_to_hex(&ours->object.oid),
2036                          oid_to_hex(&theirs->object.oid));
2037         argv_array_push(&argv, "--");
2038
2039         init_revisions(&revs, NULL);
2040         setup_revisions(argv.argc, argv.argv, &revs, NULL);
2041         if (prepare_revision_walk(&revs))
2042                 die("revision walk setup failed");
2043
2044         /* ... and count the commits on each side. */
2045         *num_ours = 0;
2046         *num_theirs = 0;
2047         while (1) {
2048                 struct commit *c = get_revision(&revs);
2049                 if (!c)
2050                         break;
2051                 if (c->object.flags & SYMMETRIC_LEFT)
2052                         (*num_ours)++;
2053                 else
2054                         (*num_theirs)++;
2055         }
2056
2057         /* clear object flags smudged by the above traversal */
2058         clear_commit_marks(ours, ALL_REV_FLAGS);
2059         clear_commit_marks(theirs, ALL_REV_FLAGS);
2060
2061         argv_array_clear(&argv);
2062         return 0;
2063 }
2064
2065 /*
2066  * Return true when there is anything to report, otherwise false.
2067  */
2068 int format_tracking_info(struct branch *branch, struct strbuf *sb)
2069 {
2070         int ours, theirs;
2071         const char *full_base;
2072         char *base;
2073         int upstream_is_gone = 0;
2074
2075         if (stat_tracking_info(branch, &ours, &theirs, &full_base) < 0) {
2076                 if (!full_base)
2077                         return 0;
2078                 upstream_is_gone = 1;
2079         }
2080
2081         base = shorten_unambiguous_ref(full_base, 0);
2082         if (upstream_is_gone) {
2083                 strbuf_addf(sb,
2084                         _("Your branch is based on '%s', but the upstream is gone.\n"),
2085                         base);
2086                 if (advice_status_hints)
2087                         strbuf_addf(sb,
2088                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
2089         } else if (!ours && !theirs) {
2090                 strbuf_addf(sb,
2091                         _("Your branch is up-to-date with '%s'.\n"),
2092                         base);
2093         } else if (!theirs) {
2094                 strbuf_addf(sb,
2095                         Q_("Your branch is ahead of '%s' by %d commit.\n",
2096                            "Your branch is ahead of '%s' by %d commits.\n",
2097                            ours),
2098                         base, ours);
2099                 if (advice_status_hints)
2100                         strbuf_addf(sb,
2101                                 _("  (use \"git push\" to publish your local commits)\n"));
2102         } else if (!ours) {
2103                 strbuf_addf(sb,
2104                         Q_("Your branch is behind '%s' by %d commit, "
2105                                "and can be fast-forwarded.\n",
2106                            "Your branch is behind '%s' by %d commits, "
2107                                "and can be fast-forwarded.\n",
2108                            theirs),
2109                         base, theirs);
2110                 if (advice_status_hints)
2111                         strbuf_addf(sb,
2112                                 _("  (use \"git pull\" to update your local branch)\n"));
2113         } else {
2114                 strbuf_addf(sb,
2115                         Q_("Your branch and '%s' have diverged,\n"
2116                                "and have %d and %d different commit each, "
2117                                "respectively.\n",
2118                            "Your branch and '%s' have diverged,\n"
2119                                "and have %d and %d different commits each, "
2120                                "respectively.\n",
2121                            theirs),
2122                         base, ours, theirs);
2123                 if (advice_status_hints)
2124                         strbuf_addf(sb,
2125                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
2126         }
2127         free(base);
2128         return 1;
2129 }
2130
2131 static int one_local_ref(const char *refname, const struct object_id *oid,
2132                          int flag, void *cb_data)
2133 {
2134         struct ref ***local_tail = cb_data;
2135         struct ref *ref;
2136
2137         /* we already know it starts with refs/ to get here */
2138         if (check_refname_format(refname + 5, 0))
2139                 return 0;
2140
2141         ref = alloc_ref(refname);
2142         oidcpy(&ref->new_oid, oid);
2143         **local_tail = ref;
2144         *local_tail = &ref->next;
2145         return 0;
2146 }
2147
2148 struct ref *get_local_heads(void)
2149 {
2150         struct ref *local_refs = NULL, **local_tail = &local_refs;
2151
2152         for_each_ref(one_local_ref, &local_tail);
2153         return local_refs;
2154 }
2155
2156 struct ref *guess_remote_head(const struct ref *head,
2157                               const struct ref *refs,
2158                               int all)
2159 {
2160         const struct ref *r;
2161         struct ref *list = NULL;
2162         struct ref **tail = &list;
2163
2164         if (!head)
2165                 return NULL;
2166
2167         /*
2168          * Some transports support directly peeking at
2169          * where HEAD points; if that is the case, then
2170          * we don't have to guess.
2171          */
2172         if (head->symref)
2173                 return copy_ref(find_ref_by_name(refs, head->symref));
2174
2175         /* If refs/heads/master could be right, it is. */
2176         if (!all) {
2177                 r = find_ref_by_name(refs, "refs/heads/master");
2178                 if (r && !oidcmp(&r->old_oid, &head->old_oid))
2179                         return copy_ref(r);
2180         }
2181
2182         /* Look for another ref that points there */
2183         for (r = refs; r; r = r->next) {
2184                 if (r != head &&
2185                     starts_with(r->name, "refs/heads/") &&
2186                     !oidcmp(&r->old_oid, &head->old_oid)) {
2187                         *tail = copy_ref(r);
2188                         tail = &((*tail)->next);
2189                         if (!all)
2190                                 break;
2191                 }
2192         }
2193
2194         return list;
2195 }
2196
2197 struct stale_heads_info {
2198         struct string_list *ref_names;
2199         struct ref **stale_refs_tail;
2200         struct refspec *refs;
2201         int ref_count;
2202 };
2203
2204 static int get_stale_heads_cb(const char *refname, const struct object_id *oid,
2205                               int flags, void *cb_data)
2206 {
2207         struct stale_heads_info *info = cb_data;
2208         struct string_list matches = STRING_LIST_INIT_DUP;
2209         struct refspec query;
2210         int i, stale = 1;
2211         memset(&query, 0, sizeof(struct refspec));
2212         query.dst = (char *)refname;
2213
2214         query_refspecs_multiple(info->refs, info->ref_count, &query, &matches);
2215         if (matches.nr == 0)
2216                 goto clean_exit; /* No matches */
2217
2218         /*
2219          * If we did find a suitable refspec and it's not a symref and
2220          * it's not in the list of refs that currently exist in that
2221          * remote, we consider it to be stale. In order to deal with
2222          * overlapping refspecs, we need to go over all of the
2223          * matching refs.
2224          */
2225         if (flags & REF_ISSYMREF)
2226                 goto clean_exit;
2227
2228         for (i = 0; stale && i < matches.nr; i++)
2229                 if (string_list_has_string(info->ref_names, matches.items[i].string))
2230                         stale = 0;
2231
2232         if (stale) {
2233                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2234                 oidcpy(&ref->new_oid, oid);
2235         }
2236
2237 clean_exit:
2238         string_list_clear(&matches, 0);
2239         return 0;
2240 }
2241
2242 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
2243 {
2244         struct ref *ref, *stale_refs = NULL;
2245         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2246         struct stale_heads_info info;
2247
2248         info.ref_names = &ref_names;
2249         info.stale_refs_tail = &stale_refs;
2250         info.refs = refs;
2251         info.ref_count = ref_count;
2252         for (ref = fetch_map; ref; ref = ref->next)
2253                 string_list_append(&ref_names, ref->name);
2254         string_list_sort(&ref_names);
2255         for_each_ref(get_stale_heads_cb, &info);
2256         string_list_clear(&ref_names, 0);
2257         return stale_refs;
2258 }
2259
2260 /*
2261  * Compare-and-swap
2262  */
2263 static void clear_cas_option(struct push_cas_option *cas)
2264 {
2265         int i;
2266
2267         for (i = 0; i < cas->nr; i++)
2268                 free(cas->entry[i].refname);
2269         free(cas->entry);
2270         memset(cas, 0, sizeof(*cas));
2271 }
2272
2273 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2274                                       const char *refname,
2275                                       size_t refnamelen)
2276 {
2277         struct push_cas *entry;
2278         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2279         entry = &cas->entry[cas->nr++];
2280         memset(entry, 0, sizeof(*entry));
2281         entry->refname = xmemdupz(refname, refnamelen);
2282         return entry;
2283 }
2284
2285 int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2286 {
2287         const char *colon;
2288         struct push_cas *entry;
2289
2290         if (unset) {
2291                 /* "--no-<option>" */
2292                 clear_cas_option(cas);
2293                 return 0;
2294         }
2295
2296         if (!arg) {
2297                 /* just "--<option>" */
2298                 cas->use_tracking_for_rest = 1;
2299                 return 0;
2300         }
2301
2302         /* "--<option>=refname" or "--<option>=refname:value" */
2303         colon = strchrnul(arg, ':');
2304         entry = add_cas_entry(cas, arg, colon - arg);
2305         if (!*colon)
2306                 entry->use_tracking = 1;
2307         else if (get_sha1(colon + 1, entry->expect))
2308                 return error("cannot parse expected object name '%s'", colon + 1);
2309         return 0;
2310 }
2311
2312 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2313 {
2314         return parse_push_cas_option(opt->value, arg, unset);
2315 }
2316
2317 int is_empty_cas(const struct push_cas_option *cas)
2318 {
2319         return !cas->use_tracking_for_rest && !cas->nr;
2320 }
2321
2322 /*
2323  * Look at remote.fetch refspec and see if we have a remote
2324  * tracking branch for the refname there.  Fill its current
2325  * value in sha1[].
2326  * If we cannot do so, return negative to signal an error.
2327  */
2328 static int remote_tracking(struct remote *remote, const char *refname,
2329                            struct object_id *oid)
2330 {
2331         char *dst;
2332
2333         dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
2334         if (!dst)
2335                 return -1; /* no tracking ref for refname at remote */
2336         if (read_ref(dst, oid->hash))
2337                 return -1; /* we know what the tracking ref is but we cannot read it */
2338         return 0;
2339 }
2340
2341 static void apply_cas(struct push_cas_option *cas,
2342                       struct remote *remote,
2343                       struct ref *ref)
2344 {
2345         int i;
2346
2347         /* Find an explicit --<option>=<name>[:<value>] entry */
2348         for (i = 0; i < cas->nr; i++) {
2349                 struct push_cas *entry = &cas->entry[i];
2350                 if (!refname_match(entry->refname, ref->name))
2351                         continue;
2352                 ref->expect_old_sha1 = 1;
2353                 if (!entry->use_tracking)
2354                         hashcpy(ref->old_oid_expect.hash, cas->entry[i].expect);
2355                 else if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2356                         ref->expect_old_no_trackback = 1;
2357                 return;
2358         }
2359
2360         /* Are we using "--<option>" to cover all? */
2361         if (!cas->use_tracking_for_rest)
2362                 return;
2363
2364         ref->expect_old_sha1 = 1;
2365         if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2366                 ref->expect_old_no_trackback = 1;
2367 }
2368
2369 void apply_push_cas(struct push_cas_option *cas,
2370                     struct remote *remote,
2371                     struct ref *remote_refs)
2372 {
2373         struct ref *ref;
2374         for (ref = remote_refs; ref; ref = ref->next)
2375                 apply_cas(cas, remote, ref);
2376 }