remote.c

   1 #include "cache.h"
   2 #include "remote.h"
   3 #include "refs.h"
   4
   5 struct counted_string {
   6         size_t len;
   7         const char *s;
   8 };
   9 struct rewrite {
  10         const char *base;
  11         size_t baselen;
  12         struct counted_string *instead_of;
  13         int instead_of_nr;
  14         int instead_of_alloc;
  15 };
  16
  17 static struct remote **remotes;
  18 static int remotes_alloc;
  19 static int remotes_nr;
  20
  21 static struct branch **branches;
  22 static int branches_alloc;
  23 static int branches_nr;
  24
  25 static struct branch *current_branch;
  26 static const char *default_remote_name;
  27
  28 static struct rewrite **rewrite;
  29 static int rewrite_alloc;
  30 static int rewrite_nr;
  31
  32 #define BUF_SIZE (2048)
  33 static char buffer[BUF_SIZE];
  34
  35 static const char *alias_url(const char *url)
  36 {
  37         int i, j;
  38         char *ret;
  39         struct counted_string *longest;
  40         int longest_i;
  41
  42         longest = NULL;
  43         longest_i = -1;
  44         for (i = 0; i < rewrite_nr; i++) {
  45                 if (!rewrite[i])
  46                         continue;
  47                 for (j = 0; j < rewrite[i]->instead_of_nr; j++) {
  48                         if (!prefixcmp(url, rewrite[i]->instead_of[j].s) &&
  49                             (!longest ||
  50                              longest->len < rewrite[i]->instead_of[j].len)) {
  51                                 longest = &(rewrite[i]->instead_of[j]);
  52                                 longest_i = i;
  53                         }
  54                 }
  55         }
  56         if (!longest)
  57                 return url;
  58
  59         ret = malloc(rewrite[longest_i]->baselen +
  60                      (strlen(url) - longest->len) + 1);
  61         strcpy(ret, rewrite[longest_i]->base);
  62         strcpy(ret + rewrite[longest_i]->baselen, url + longest->len);
  63         return ret;
  64 }
  65
  66 static void add_push_refspec(struct remote *remote, const char *ref)
  67 {
  68         ALLOC_GROW(remote->push_refspec,
  69                    remote->push_refspec_nr + 1,
  70                    remote->push_refspec_alloc);
  71         remote->push_refspec[remote->push_refspec_nr++] = ref;
  72 }
  73
  74 static void add_fetch_refspec(struct remote *remote, const char *ref)
  75 {
  76         ALLOC_GROW(remote->fetch_refspec,
  77                    remote->fetch_refspec_nr + 1,
  78                    remote->fetch_refspec_alloc);
  79         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
  80 }
  81
  82 static void add_url(struct remote *remote, const char *url)
  83 {
  84         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
  85         remote->url[remote->url_nr++] = url;
  86 }
  87
  88 static void add_url_alias(struct remote *remote, const char *url)
  89 {
  90         add_url(remote, alias_url(url));
  91 }
  92
  93 static struct remote *make_remote(const char *name, int len)
  94 {
  95         struct remote *ret;
  96         int i;
  97
  98         for (i = 0; i < remotes_nr; i++) {
  99                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
 100                            !remotes[i]->name[len]) :
 101                     !strcmp(name, remotes[i]->name))
 102                         return remotes[i];
 103         }
 104
 105         ret = xcalloc(1, sizeof(struct remote));
 106         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 107         remotes[remotes_nr++] = ret;
 108         if (len)
 109                 ret->name = xstrndup(name, len);
 110         else
 111                 ret->name = xstrdup(name);
 112         return ret;
 113 }
 114
 115 static void add_merge(struct branch *branch, const char *name)
 116 {
 117         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 118                    branch->merge_alloc);
 119         branch->merge_name[branch->merge_nr++] = name;
 120 }
 121
 122 static struct branch *make_branch(const char *name, int len)
 123 {
 124         struct branch *ret;
 125         int i;
 126         char *refname;
 127
 128         for (i = 0; i < branches_nr; i++) {
 129                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 130                            !branches[i]->name[len]) :
 131                     !strcmp(name, branches[i]->name))
 132                         return branches[i];
 133         }
 134
 135         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 136         ret = xcalloc(1, sizeof(struct branch));
 137         branches[branches_nr++] = ret;
 138         if (len)
 139                 ret->name = xstrndup(name, len);
 140         else
 141                 ret->name = xstrdup(name);
 142         refname = malloc(strlen(name) + strlen("refs/heads/") + 1);
 143         strcpy(refname, "refs/heads/");
 144         strcpy(refname + strlen("refs/heads/"), ret->name);
 145         ret->refname = refname;
 146
 147         return ret;
 148 }
 149
 150 static struct rewrite *make_rewrite(const char *base, int len)
 151 {
 152         struct rewrite *ret;
 153         int i;
 154
 155         for (i = 0; i < rewrite_nr; i++) {
 156                 if (len
 157                     ? (len == rewrite[i]->baselen &&
 158                        !strncmp(base, rewrite[i]->base, len))
 159                     : !strcmp(base, rewrite[i]->base))
 160                         return rewrite[i];
 161         }
 162
 163         ALLOC_GROW(rewrite, rewrite_nr + 1, rewrite_alloc);
 164         ret = xcalloc(1, sizeof(struct rewrite));
 165         rewrite[rewrite_nr++] = ret;
 166         if (len) {
 167                 ret->base = xstrndup(base, len);
 168                 ret->baselen = len;
 169         }
 170         else {
 171                 ret->base = xstrdup(base);
 172                 ret->baselen = strlen(base);
 173         }
 174         return ret;
 175 }
 176
 177 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 178 {
 179         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 180         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 181         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 182         rewrite->instead_of_nr++;
 183 }
 184
 185 static void read_remotes_file(struct remote *remote)
 186 {
 187         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 188
 189         if (!f)
 190                 return;
 191         while (fgets(buffer, BUF_SIZE, f)) {
 192                 int value_list;
 193                 char *s, *p;
 194
 195                 if (!prefixcmp(buffer, "URL:")) {
 196                         value_list = 0;
 197                         s = buffer + 4;
 198                 } else if (!prefixcmp(buffer, "Push:")) {
 199                         value_list = 1;
 200                         s = buffer + 5;
 201                 } else if (!prefixcmp(buffer, "Pull:")) {
 202                         value_list = 2;
 203                         s = buffer + 5;
 204                 } else
 205                         continue;
 206
 207                 while (isspace(*s))
 208                         s++;
 209                 if (!*s)
 210                         continue;
 211
 212                 p = s + strlen(s);
 213                 while (isspace(p[-1]))
 214                         *--p = 0;
 215
 216                 switch (value_list) {
 217                 case 0:
 218                         add_url_alias(remote, xstrdup(s));
 219                         break;
 220                 case 1:
 221                         add_push_refspec(remote, xstrdup(s));
 222                         break;
 223                 case 2:
 224                         add_fetch_refspec(remote, xstrdup(s));
 225                         break;
 226                 }
 227         }
 228         fclose(f);
 229 }
 230
 231 static void read_branches_file(struct remote *remote)
 232 {
 233         const char *slash = strchr(remote->name, '/');
 234         char *frag;
 235         char *branch;
 236         int n = slash ? slash - remote->name : 1000;
 237         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
 238         char *s, *p;
 239         int len;
 240
 241         if (!f)
 242                 return;
 243         s = fgets(buffer, BUF_SIZE, f);
 244         fclose(f);
 245         if (!s)
 246                 return;
 247         while (isspace(*s))
 248                 s++;
 249         if (!*s)
 250                 return;
 251         p = s + strlen(s);
 252         while (isspace(p[-1]))
 253                 *--p = 0;
 254         len = p - s;
 255         if (slash)
 256                 len += strlen(slash);
 257         p = xmalloc(len + 1);
 258         strcpy(p, s);
 259         if (slash)
 260                 strcat(p, slash);
 261         frag = strchr(p, '#');
 262         if (frag) {
 263                 *(frag++) = '\0';
 264                 branch = xmalloc(strlen(frag) + 12);
 265                 strcpy(branch, "refs/heads/");
 266                 strcat(branch, frag);
 267         } else {
 268                 branch = "refs/heads/master";
 269         }
 270         add_url_alias(remote, p);
 271         add_fetch_refspec(remote, branch);
 272         remote->fetch_tags = 1; /* always auto-follow */
 273 }
 274
 275 static int handle_config(const char *key, const char *value)
 276 {
 277         const char *name;
 278         const char *subkey;
 279         struct remote *remote;
 280         struct branch *branch;
 281         if (!prefixcmp(key, "branch.")) {
 282                 name = key + 7;
 283                 subkey = strrchr(name, '.');
 284                 if (!subkey)
 285                         return 0;
 286                 branch = make_branch(name, subkey - name);
 287                 if (!strcmp(subkey, ".remote")) {
 288                         if (!value)
 289                                 return config_error_nonbool(key);
 290                         branch->remote_name = xstrdup(value);
 291                         if (branch == current_branch)
 292                                 default_remote_name = branch->remote_name;
 293                 } else if (!strcmp(subkey, ".merge")) {
 294                         if (!value)
 295                                 return config_error_nonbool(key);
 296                         add_merge(branch, xstrdup(value));
 297                 }
 298                 return 0;
 299         }
 300         if (!prefixcmp(key, "url.")) {
 301                 struct rewrite *rewrite;
 302                 name = key + 5;
 303                 subkey = strrchr(name, '.');
 304                 if (!subkey)
 305                         return 0;
 306                 rewrite = make_rewrite(name, subkey - name);
 307                 if (!strcmp(subkey, ".insteadof")) {
 308                         if (!value)
 309                                 return config_error_nonbool(key);
 310                         add_instead_of(rewrite, xstrdup(value));
 311                 }
 312         }
 313         if (prefixcmp(key,  "remote."))
 314                 return 0;
 315         name = key + 7;
 316         subkey = strrchr(name, '.');
 317         if (!subkey)
 318                 return error("Config with no key for remote %s", name);
 319         if (*subkey == '/') {
 320                 warning("Config remote shorthand cannot begin with '/': %s", name);
 321                 return 0;
 322         }
 323         remote = make_remote(name, subkey - name);
 324         if (!value) {
 325                 /* if we ever have a boolean variable, e.g. "remote.*.disabled"
 326                  * [remote "frotz"]
 327                  *      disabled
 328                  * is a valid way to set it to true; we get NULL in value so
 329                  * we need to handle it here.
 330                  *
 331                  * if (!strcmp(subkey, ".disabled")) {
 332                  *      val = git_config_bool(key, value);
 333                  *      return 0;
 334                  * } else
 335                  *
 336                  */
 337                 return 0; /* ignore unknown booleans */
 338         }
 339         if (!strcmp(subkey, ".url")) {
 340                 add_url(remote, xstrdup(value));
 341         } else if (!strcmp(subkey, ".push")) {
 342                 add_push_refspec(remote, xstrdup(value));
 343         } else if (!strcmp(subkey, ".fetch")) {
 344                 add_fetch_refspec(remote, xstrdup(value));
 345         } else if (!strcmp(subkey, ".receivepack")) {
 346                 if (!remote->receivepack)
 347                         remote->receivepack = xstrdup(value);
 348                 else
 349                         error("more than one receivepack given, using the first");
 350         } else if (!strcmp(subkey, ".uploadpack")) {
 351                 if (!remote->uploadpack)
 352                         remote->uploadpack = xstrdup(value);
 353                 else
 354                         error("more than one uploadpack given, using the first");
 355         } else if (!strcmp(subkey, ".tagopt")) {
 356                 if (!strcmp(value, "--no-tags"))
 357                         remote->fetch_tags = -1;
 358         } else if (!strcmp(subkey, ".proxy")) {
 359                 remote->http_proxy = xstrdup(value);
 360         }
 361         return 0;
 362 }
 363
 364 static void alias_all_urls(void)
 365 {
 366         int i, j;
 367         for (i = 0; i < remotes_nr; i++) {
 368                 if (!remotes[i])
 369                         continue;
 370                 for (j = 0; j < remotes[i]->url_nr; j++) {
 371                         remotes[i]->url[j] = alias_url(remotes[i]->url[j]);
 372                 }
 373         }
 374 }
 375
 376 static void read_config(void)
 377 {
 378         unsigned char sha1[20];
 379         const char *head_ref;
 380         int flag;
 381         if (default_remote_name) // did this already
 382                 return;
 383         default_remote_name = xstrdup("origin");
 384         current_branch = NULL;
 385         head_ref = resolve_ref("HEAD", sha1, 0, &flag);
 386         if (head_ref && (flag & REF_ISSYMREF) &&
 387             !prefixcmp(head_ref, "refs/heads/")) {
 388                 current_branch =
 389                         make_branch(head_ref + strlen("refs/heads/"), 0);
 390         }
 391         git_config(handle_config);
 392         alias_all_urls();
 393 }
 394
 395 struct refspec *parse_ref_spec(int nr_refspec, const char **refspec)
 396 {
 397         int i;
 398         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 399         for (i = 0; i < nr_refspec; i++) {
 400                 const char *sp, *ep, *gp;
 401                 sp = refspec[i];
 402                 if (*sp == '+') {
 403                         rs[i].force = 1;
 404                         sp++;
 405                 }
 406                 gp = strchr(sp, '*');
 407                 ep = strchr(sp, ':');
 408                 if (gp && ep && gp > ep)
 409                         gp = NULL;
 410                 if (ep) {
 411                         if (ep[1]) {
 412                                 const char *glob = strchr(ep + 1, '*');
 413                                 if (!glob)
 414                                         gp = NULL;
 415                                 if (gp)
 416                                         rs[i].dst = xstrndup(ep + 1,
 417                                                              glob - ep - 1);
 418                                 else
 419                                         rs[i].dst = xstrdup(ep + 1);
 420                         }
 421                 } else {
 422                         ep = sp + strlen(sp);
 423                 }
 424                 if (gp) {
 425                         rs[i].pattern = 1;
 426                         ep = gp;
 427                 }
 428                 rs[i].src = xstrndup(sp, ep - sp);
 429         }
 430         return rs;
 431 }
 432
 433 static int valid_remote_nick(const char *name)
 434 {
 435         if (!name[0] || /* not empty */
 436             (name[0] == '.' && /* not "." */
 437              (!name[1] || /* not ".." */
 438               (name[1] == '.' && !name[2]))))
 439                 return 0;
 440         return !strchr(name, '/'); /* no slash */
 441 }
 442
 443 struct remote *remote_get(const char *name)
 444 {
 445         struct remote *ret;
 446
 447         read_config();
 448         if (!name)
 449                 name = default_remote_name;
 450         ret = make_remote(name, 0);
 451         if (valid_remote_nick(name)) {
 452                 if (!ret->url)
 453                         read_remotes_file(ret);
 454                 if (!ret->url)
 455                         read_branches_file(ret);
 456         }
 457         if (!ret->url)
 458                 add_url_alias(ret, name);
 459         if (!ret->url)
 460                 return NULL;
 461         ret->fetch = parse_ref_spec(ret->fetch_refspec_nr, ret->fetch_refspec);
 462         ret->push = parse_ref_spec(ret->push_refspec_nr, ret->push_refspec);
 463         return ret;
 464 }
 465
 466 int for_each_remote(each_remote_fn fn, void *priv)
 467 {
 468         int i, result = 0;
 469         read_config();
 470         for (i = 0; i < remotes_nr && !result; i++) {
 471                 struct remote *r = remotes[i];
 472                 if (!r)
 473                         continue;
 474                 if (!r->fetch)
 475                         r->fetch = parse_ref_spec(r->fetch_refspec_nr,
 476                                         r->fetch_refspec);
 477                 if (!r->push)
 478                         r->push = parse_ref_spec(r->push_refspec_nr,
 479                                         r->push_refspec);
 480                 result = fn(r, priv);
 481         }
 482         return result;
 483 }
 484
 485 void ref_remove_duplicates(struct ref *ref_map)
 486 {
 487         struct ref **posn;
 488         struct ref *next;
 489         for (; ref_map; ref_map = ref_map->next) {
 490                 if (!ref_map->peer_ref)
 491                         continue;
 492                 posn = &ref_map->next;
 493                 while (*posn) {
 494                         if ((*posn)->peer_ref &&
 495                             !strcmp((*posn)->peer_ref->name,
 496                                     ref_map->peer_ref->name)) {
 497                                 if (strcmp((*posn)->name, ref_map->name))
 498                                         die("%s tracks both %s and %s",
 499                                             ref_map->peer_ref->name,
 500                                             (*posn)->name, ref_map->name);
 501                                 next = (*posn)->next;
 502                                 free((*posn)->peer_ref);
 503                                 free(*posn);
 504                                 *posn = next;
 505                         } else {
 506                                 posn = &(*posn)->next;
 507                         }
 508                 }
 509         }
 510 }
 511
 512 int remote_has_url(struct remote *remote, const char *url)
 513 {
 514         int i;
 515         for (i = 0; i < remote->url_nr; i++) {
 516                 if (!strcmp(remote->url[i], url))
 517                         return 1;
 518         }
 519         return 0;
 520 }
 521
 522 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 523 {
 524         int find_src = refspec->src == NULL;
 525         char *needle, **result;
 526         int i;
 527
 528         if (find_src) {
 529                 if (!refspec->dst)
 530                         return error("find_tracking: need either src or dst");
 531                 needle = refspec->dst;
 532                 result = &refspec->src;
 533         } else {
 534                 needle = refspec->src;
 535                 result = &refspec->dst;
 536         }
 537
 538         for (i = 0; i < remote->fetch_refspec_nr; i++) {
 539                 struct refspec *fetch = &remote->fetch[i];
 540                 const char *key = find_src ? fetch->dst : fetch->src;
 541                 const char *value = find_src ? fetch->src : fetch->dst;
 542                 if (!fetch->dst)
 543                         continue;
 544                 if (fetch->pattern) {
 545                         if (!prefixcmp(needle, key)) {
 546                                 *result = xmalloc(strlen(value) +
 547                                                   strlen(needle) -
 548                                                   strlen(key) + 1);
 549                                 strcpy(*result, value);
 550                                 strcpy(*result + strlen(value),
 551                                        needle + strlen(key));
 552                                 refspec->force = fetch->force;
 553                                 return 0;
 554                         }
 555                 } else if (!strcmp(needle, key)) {
 556                         *result = xstrdup(value);
 557                         refspec->force = fetch->force;
 558                         return 0;
 559                 }
 560         }
 561         return -1;
 562 }
 563
 564 struct ref *alloc_ref(unsigned namelen)
 565 {
 566         struct ref *ret = xmalloc(sizeof(struct ref) + namelen);
 567         memset(ret, 0, sizeof(struct ref) + namelen);
 568         return ret;
 569 }
 570
 571 static struct ref *copy_ref(const struct ref *ref)
 572 {
 573         struct ref *ret = xmalloc(sizeof(struct ref) + strlen(ref->name) + 1);
 574         memcpy(ret, ref, sizeof(struct ref) + strlen(ref->name) + 1);
 575         ret->next = NULL;
 576         return ret;
 577 }
 578
 579 struct ref *copy_ref_list(const struct ref *ref)
 580 {
 581         struct ref *ret = NULL;
 582         struct ref **tail = &ret;
 583         while (ref) {
 584                 *tail = copy_ref(ref);
 585                 ref = ref->next;
 586                 tail = &((*tail)->next);
 587         }
 588         return ret;
 589 }
 590
 591 void free_refs(struct ref *ref)
 592 {
 593         struct ref *next;
 594         while (ref) {
 595                 next = ref->next;
 596                 if (ref->peer_ref)
 597                         free(ref->peer_ref);
 598                 free(ref);
 599                 ref = next;
 600         }
 601 }
 602
 603 static int count_refspec_match(const char *pattern,
 604                                struct ref *refs,
 605                                struct ref **matched_ref)
 606 {
 607         int patlen = strlen(pattern);
 608         struct ref *matched_weak = NULL;
 609         struct ref *matched = NULL;
 610         int weak_match = 0;
 611         int match = 0;
 612
 613         for (weak_match = match = 0; refs; refs = refs->next) {
 614                 char *name = refs->name;
 615                 int namelen = strlen(name);
 616
 617                 if (!refname_match(pattern, name, ref_rev_parse_rules))
 618                         continue;
 619
 620                 /* A match is "weak" if it is with refs outside
 621                  * heads or tags, and did not specify the pattern
 622                  * in full (e.g. "refs/remotes/origin/master") or at
 623                  * least from the toplevel (e.g. "remotes/origin/master");
 624                  * otherwise "git push $URL master" would result in
 625                  * ambiguity between remotes/origin/master and heads/master
 626                  * at the remote site.
 627                  */
 628                 if (namelen != patlen &&
 629                     patlen != namelen - 5 &&
 630                     prefixcmp(name, "refs/heads/") &&
 631                     prefixcmp(name, "refs/tags/")) {
 632                         /* We want to catch the case where only weak
 633                          * matches are found and there are multiple
 634                          * matches, and where more than one strong
 635                          * matches are found, as ambiguous.  One
 636                          * strong match with zero or more weak matches
 637                          * are acceptable as a unique match.
 638                          */
 639                         matched_weak = refs;
 640                         weak_match++;
 641                 }
 642                 else {
 643                         matched = refs;
 644                         match++;
 645                 }
 646         }
 647         if (!matched) {
 648                 *matched_ref = matched_weak;
 649                 return weak_match;
 650         }
 651         else {
 652                 *matched_ref = matched;
 653                 return match;
 654         }
 655 }
 656
 657 static void tail_link_ref(struct ref *ref, struct ref ***tail)
 658 {
 659         **tail = ref;
 660         while (ref->next)
 661                 ref = ref->next;
 662         *tail = &ref->next;
 663 }
 664
 665 static struct ref *try_explicit_object_name(const char *name)
 666 {
 667         unsigned char sha1[20];
 668         struct ref *ref;
 669         int len;
 670
 671         if (!*name) {
 672                 ref = alloc_ref(20);
 673                 strcpy(ref->name, "(delete)");
 674                 hashclr(ref->new_sha1);
 675                 return ref;
 676         }
 677         if (get_sha1(name, sha1))
 678                 return NULL;
 679         len = strlen(name) + 1;
 680         ref = alloc_ref(len);
 681         memcpy(ref->name, name, len);
 682         hashcpy(ref->new_sha1, sha1);
 683         return ref;
 684 }
 685
 686 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
 687 {
 688         struct ref *ret;
 689         size_t len;
 690
 691         len = strlen(name) + 1;
 692         ret = alloc_ref(len);
 693         memcpy(ret->name, name, len);
 694         tail_link_ref(ret, tail);
 695         return ret;
 696 }
 697
 698 static int match_explicit(struct ref *src, struct ref *dst,
 699                           struct ref ***dst_tail,
 700                           struct refspec *rs,
 701                           int errs)
 702 {
 703         struct ref *matched_src, *matched_dst;
 704
 705         const char *dst_value = rs->dst;
 706
 707         if (rs->pattern)
 708                 return errs;
 709
 710         matched_src = matched_dst = NULL;
 711         switch (count_refspec_match(rs->src, src, &matched_src)) {
 712         case 1:
 713                 break;
 714         case 0:
 715                 /* The source could be in the get_sha1() format
 716                  * not a reference name.  :refs/other is a
 717                  * way to delete 'other' ref at the remote end.
 718                  */
 719                 matched_src = try_explicit_object_name(rs->src);
 720                 if (!matched_src)
 721                         error("src refspec %s does not match any.", rs->src);
 722                 break;
 723         default:
 724                 matched_src = NULL;
 725                 error("src refspec %s matches more than one.", rs->src);
 726                 break;
 727         }
 728
 729         if (!matched_src)
 730                 errs = 1;
 731
 732         if (!dst_value) {
 733                 unsigned char sha1[20];
 734                 int flag;
 735
 736                 if (!matched_src)
 737                         return errs;
 738                 dst_value = resolve_ref(matched_src->name, sha1, 1, &flag);
 739                 if (!dst_value ||
 740                     ((flag & REF_ISSYMREF) &&
 741                      prefixcmp(dst_value, "refs/heads/")))
 742                         die("%s cannot be resolved to branch.",
 743                             matched_src->name);
 744         }
 745
 746         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
 747         case 1:
 748                 break;
 749         case 0:
 750                 if (!memcmp(dst_value, "refs/", 5))
 751                         matched_dst = make_linked_ref(dst_value, dst_tail);
 752                 else
 753                         error("dst refspec %s does not match any "
 754                               "existing ref on the remote and does "
 755                               "not start with refs/.", dst_value);
 756                 break;
 757         default:
 758                 matched_dst = NULL;
 759                 error("dst refspec %s matches more than one.",
 760                       dst_value);
 761                 break;
 762         }
 763         if (errs || !matched_dst)
 764                 return 1;
 765         if (matched_dst->peer_ref) {
 766                 errs = 1;
 767                 error("dst ref %s receives from more than one src.",
 768                       matched_dst->name);
 769         }
 770         else {
 771                 matched_dst->peer_ref = matched_src;
 772                 matched_dst->force = rs->force;
 773         }
 774         return errs;
 775 }
 776
 777 static int match_explicit_refs(struct ref *src, struct ref *dst,
 778                                struct ref ***dst_tail, struct refspec *rs,
 779                                int rs_nr)
 780 {
 781         int i, errs;
 782         for (i = errs = 0; i < rs_nr; i++)
 783                 errs |= match_explicit(src, dst, dst_tail, &rs[i], errs);
 784         return -errs;
 785 }
 786
 787 static const struct refspec *check_pattern_match(const struct refspec *rs,
 788                                                  int rs_nr,
 789                                                  const struct ref *src)
 790 {
 791         int i;
 792         for (i = 0; i < rs_nr; i++) {
 793                 if (rs[i].pattern && !prefixcmp(src->name, rs[i].src))
 794                         return rs + i;
 795         }
 796         return NULL;
 797 }
 798
 799 /*
 800  * Note. This is used only by "push"; refspec matching rules for
 801  * push and fetch are subtly different, so do not try to reuse it
 802  * without thinking.
 803  */
 804 int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
 805                int nr_refspec, const char **refspec, int flags)
 806 {
 807         struct refspec *rs =
 808                 parse_ref_spec(nr_refspec, (const char **) refspec);
 809         int send_all = flags & MATCH_REFS_ALL;
 810         int send_mirror = flags & MATCH_REFS_MIRROR;
 811
 812         if (match_explicit_refs(src, dst, dst_tail, rs, nr_refspec))
 813                 return -1;
 814
 815         /* pick the remainder */
 816         for ( ; src; src = src->next) {
 817                 struct ref *dst_peer;
 818                 const struct refspec *pat = NULL;
 819                 char *dst_name;
 820                 if (src->peer_ref)
 821                         continue;
 822                 if (nr_refspec) {
 823                         pat = check_pattern_match(rs, nr_refspec, src);
 824                         if (!pat)
 825                                 continue;
 826                 }
 827                 else if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
 828                         /*
 829                          * "matching refs"; traditionally we pushed everything
 830                          * including refs outside refs/heads/ hierarchy, but
 831                          * that does not make much sense these days.
 832                          */
 833                         continue;
 834
 835                 if (pat) {
 836                         const char *dst_side = pat->dst ? pat->dst : pat->src;
 837                         dst_name = xmalloc(strlen(dst_side) +
 838                                            strlen(src->name) -
 839                                            strlen(pat->src) + 2);
 840                         strcpy(dst_name, dst_side);
 841                         strcat(dst_name, src->name + strlen(pat->src));
 842                 } else
 843                         dst_name = xstrdup(src->name);
 844                 dst_peer = find_ref_by_name(dst, dst_name);
 845                 if (dst_peer && dst_peer->peer_ref)
 846                         /* We're already sending something to this ref. */
 847                         goto free_name;
 848
 849                 if (!dst_peer && !nr_refspec && !(send_all || send_mirror))
 850                         /*
 851                          * Remote doesn't have it, and we have no
 852                          * explicit pattern, and we don't have
 853                          * --all nor --mirror.
 854                          */
 855                         goto free_name;
 856                 if (!dst_peer) {
 857                         /* Create a new one and link it */
 858                         dst_peer = make_linked_ref(dst_name, dst_tail);
 859                         hashcpy(dst_peer->new_sha1, src->new_sha1);
 860                 }
 861                 dst_peer->peer_ref = src;
 862                 if (pat)
 863                         dst_peer->force = pat->force;
 864         free_name:
 865                 free(dst_name);
 866         }
 867         return 0;
 868 }
 869
 870 struct branch *branch_get(const char *name)
 871 {
 872         struct branch *ret;
 873
 874         read_config();
 875         if (!name || !*name || !strcmp(name, "HEAD"))
 876                 ret = current_branch;
 877         else
 878                 ret = make_branch(name, 0);
 879         if (ret && ret->remote_name) {
 880                 ret->remote = remote_get(ret->remote_name);
 881                 if (ret->merge_nr) {
 882                         int i;
 883                         ret->merge = xcalloc(sizeof(*ret->merge),
 884                                              ret->merge_nr);
 885                         for (i = 0; i < ret->merge_nr; i++) {
 886                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
 887                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
 888                                 remote_find_tracking(ret->remote,
 889                                                      ret->merge[i]);
 890                         }
 891                 }
 892         }
 893         return ret;
 894 }
 895
 896 int branch_has_merge_config(struct branch *branch)
 897 {
 898         return branch && !!branch->merge;
 899 }
 900
 901 int branch_merge_matches(struct branch *branch,
 902                                  int i,
 903                                  const char *refname)
 904 {
 905         if (!branch || i < 0 || i >= branch->merge_nr)
 906                 return 0;
 907         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
 908 }
 909
 910 static struct ref *get_expanded_map(const struct ref *remote_refs,
 911                                     const struct refspec *refspec)
 912 {
 913         const struct ref *ref;
 914         struct ref *ret = NULL;
 915         struct ref **tail = &ret;
 916
 917         int remote_prefix_len = strlen(refspec->src);
 918         int local_prefix_len = strlen(refspec->dst);
 919
 920         for (ref = remote_refs; ref; ref = ref->next) {
 921                 if (strchr(ref->name, '^'))
 922                         continue; /* a dereference item */
 923                 if (!prefixcmp(ref->name, refspec->src)) {
 924                         const char *match;
 925                         struct ref *cpy = copy_ref(ref);
 926                         match = ref->name + remote_prefix_len;
 927
 928                         cpy->peer_ref = alloc_ref(local_prefix_len +
 929                                                   strlen(match) + 1);
 930                         sprintf(cpy->peer_ref->name, "%s%s",
 931                                 refspec->dst, match);
 932                         if (refspec->force)
 933                                 cpy->peer_ref->force = 1;
 934                         *tail = cpy;
 935                         tail = &cpy->next;
 936                 }
 937         }
 938
 939         return ret;
 940 }
 941
 942 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
 943 {
 944         const struct ref *ref;
 945         for (ref = refs; ref; ref = ref->next) {
 946                 if (refname_match(name, ref->name, ref_fetch_rules))
 947                         return ref;
 948         }
 949         return NULL;
 950 }
 951
 952 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
 953 {
 954         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
 955
 956         if (!ref)
 957                 return NULL;
 958
 959         return copy_ref(ref);
 960 }
 961
 962 static struct ref *get_local_ref(const char *name)
 963 {
 964         struct ref *ret;
 965         if (!name)
 966                 return NULL;
 967
 968         if (!prefixcmp(name, "refs/")) {
 969                 ret = alloc_ref(strlen(name) + 1);
 970                 strcpy(ret->name, name);
 971                 return ret;
 972         }
 973
 974         if (!prefixcmp(name, "heads/") ||
 975             !prefixcmp(name, "tags/") ||
 976             !prefixcmp(name, "remotes/")) {
 977                 ret = alloc_ref(strlen(name) + 6);
 978                 sprintf(ret->name, "refs/%s", name);
 979                 return ret;
 980         }
 981
 982         ret = alloc_ref(strlen(name) + 12);
 983         sprintf(ret->name, "refs/heads/%s", name);
 984         return ret;
 985 }
 986
 987 int get_fetch_map(const struct ref *remote_refs,
 988                   const struct refspec *refspec,
 989                   struct ref ***tail,
 990                   int missing_ok)
 991 {
 992         struct ref *ref_map, *rm;
 993
 994         if (refspec->pattern) {
 995                 ref_map = get_expanded_map(remote_refs, refspec);
 996         } else {
 997                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
 998
 999                 ref_map = get_remote_ref(remote_refs, name);
1000                 if (!missing_ok && !ref_map)
1001                         die("Couldn't find remote ref %s", name);
1002                 if (ref_map) {
1003                         ref_map->peer_ref = get_local_ref(refspec->dst);
1004                         if (ref_map->peer_ref && refspec->force)
1005                                 ref_map->peer_ref->force = 1;
1006                 }
1007         }
1008
1009         for (rm = ref_map; rm; rm = rm->next) {
1010                 if (rm->peer_ref && check_ref_format(rm->peer_ref->name + 5))
1011                         die("* refusing to create funny ref '%s' locally",
1012                             rm->peer_ref->name);
1013         }
1014
1015         if (ref_map)
1016                 tail_link_ref(ref_map, tail);
1017
1018         return 0;
1019 }