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         } else if (!strcmp(subkey, ".skipdefaultupdate"))
 361                 remote->skip_default_update = 1;
 362         return 0;
 363 }
 364
 365 static void alias_all_urls(void)
 366 {
 367         int i, j;
 368         for (i = 0; i < remotes_nr; i++) {
 369                 if (!remotes[i])
 370                         continue;
 371                 for (j = 0; j < remotes[i]->url_nr; j++) {
 372                         remotes[i]->url[j] = alias_url(remotes[i]->url[j]);
 373                 }
 374         }
 375 }
 376
 377 static void read_config(void)
 378 {
 379         unsigned char sha1[20];
 380         const char *head_ref;
 381         int flag;
 382         if (default_remote_name) // did this already
 383                 return;
 384         default_remote_name = xstrdup("origin");
 385         current_branch = NULL;
 386         head_ref = resolve_ref("HEAD", sha1, 0, &flag);
 387         if (head_ref && (flag & REF_ISSYMREF) &&
 388             !prefixcmp(head_ref, "refs/heads/")) {
 389                 current_branch =
 390                         make_branch(head_ref + strlen("refs/heads/"), 0);
 391         }
 392         git_config(handle_config);
 393         alias_all_urls();
 394 }
 395
 396 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch)
 397 {
 398         int i;
 399         int st;
 400         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 401
 402         for (i = 0; i < nr_refspec; i++) {
 403                 size_t llen, rlen;
 404                 int is_glob;
 405                 const char *lhs, *rhs;
 406
 407                 llen = rlen = is_glob = 0;
 408
 409                 lhs = refspec[i];
 410                 if (*lhs == '+') {
 411                         rs[i].force = 1;
 412                         lhs++;
 413                 }
 414
 415                 rhs = strrchr(lhs, ':');
 416                 if (rhs) {
 417                         rhs++;
 418                         rlen = strlen(rhs);
 419                         is_glob = (2 <= rlen && !strcmp(rhs + rlen - 2, "/*"));
 420                         if (is_glob)
 421                                 rlen -= 2;
 422                         rs[i].dst = xstrndup(rhs, rlen);
 423                 }
 424
 425                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 426                 if (2 <= llen && !memcmp(lhs + llen - 2, "/*", 2)) {
 427                         if ((rhs && !is_glob) || (!rhs && fetch))
 428                                 goto invalid;
 429                         is_glob = 1;
 430                         llen -= 2;
 431                 } else if (rhs && is_glob) {
 432                         goto invalid;
 433                 }
 434
 435                 rs[i].pattern = is_glob;
 436                 rs[i].src = xstrndup(lhs, llen);
 437
 438                 if (fetch) {
 439                         /*
 440                          * LHS
 441                          * - empty is allowed; it means HEAD.
 442                          * - otherwise it must be a valid looking ref.
 443                          */
 444                         if (!*rs[i].src)
 445                                 ; /* empty is ok */
 446                         else {
 447                                 st = check_ref_format(rs[i].src);
 448                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 449                                         goto invalid;
 450                         }
 451                         /*
 452                          * RHS
 453                          * - missing is ok, and is same as empty.
 454                          * - empty is ok; it means not to store.
 455                          * - otherwise it must be a valid looking ref.
 456                          */
 457                         if (!rs[i].dst) {
 458                                 ; /* ok */
 459                         } else if (!*rs[i].dst) {
 460                                 ; /* ok */
 461                         } else {
 462                                 st = check_ref_format(rs[i].dst);
 463                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 464                                         goto invalid;
 465                         }
 466                 } else {
 467                         /*
 468                          * LHS
 469                          * - empty is allowed; it means delete.
 470                          * - when wildcarded, it must be a valid looking ref.
 471                          * - otherwise, it must be an extended SHA-1, but
 472                          *   there is no existing way to validate this.
 473                          */
 474                         if (!*rs[i].src)
 475                                 ; /* empty is ok */
 476                         else if (is_glob) {
 477                                 st = check_ref_format(rs[i].src);
 478                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 479                                         goto invalid;
 480                         }
 481                         else
 482                                 ; /* anything goes, for now */
 483                         /*
 484                          * RHS
 485                          * - missing is allowed, but LHS then must be a
 486                          *   valid looking ref.
 487                          * - empty is not allowed.
 488                          * - otherwise it must be a valid looking ref.
 489                          */
 490                         if (!rs[i].dst) {
 491                                 st = check_ref_format(rs[i].src);
 492                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 493                                         goto invalid;
 494                         } else if (!*rs[i].dst) {
 495                                 goto invalid;
 496                         } else {
 497                                 st = check_ref_format(rs[i].dst);
 498                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 499                                         goto invalid;
 500                         }
 501                 }
 502         }
 503         return rs;
 504
 505  invalid:
 506         die("Invalid refspec '%s'", refspec[i]);
 507 }
 508
 509 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 510 {
 511         return parse_refspec_internal(nr_refspec, refspec, 1);
 512 }
 513
 514 struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 515 {
 516         return parse_refspec_internal(nr_refspec, refspec, 0);
 517 }
 518
 519 static int valid_remote_nick(const char *name)
 520 {
 521         if (!name[0] || /* not empty */
 522             (name[0] == '.' && /* not "." */
 523              (!name[1] || /* not ".." */
 524               (name[1] == '.' && !name[2]))))
 525                 return 0;
 526         return !strchr(name, '/'); /* no slash */
 527 }
 528
 529 struct remote *remote_get(const char *name)
 530 {
 531         struct remote *ret;
 532
 533         read_config();
 534         if (!name)
 535                 name = default_remote_name;
 536         ret = make_remote(name, 0);
 537         if (valid_remote_nick(name)) {
 538                 if (!ret->url)
 539                         read_remotes_file(ret);
 540                 if (!ret->url)
 541                         read_branches_file(ret);
 542         }
 543         if (!ret->url)
 544                 add_url_alias(ret, name);
 545         if (!ret->url)
 546                 return NULL;
 547         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 548         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 549         return ret;
 550 }
 551
 552 int for_each_remote(each_remote_fn fn, void *priv)
 553 {
 554         int i, result = 0;
 555         read_config();
 556         for (i = 0; i < remotes_nr && !result; i++) {
 557                 struct remote *r = remotes[i];
 558                 if (!r)
 559                         continue;
 560                 if (!r->fetch)
 561                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 562                                                        r->fetch_refspec);
 563                 if (!r->push)
 564                         r->push = parse_push_refspec(r->push_refspec_nr,
 565                                                      r->push_refspec);
 566                 result = fn(r, priv);
 567         }
 568         return result;
 569 }
 570
 571 void ref_remove_duplicates(struct ref *ref_map)
 572 {
 573         struct ref **posn;
 574         struct ref *next;
 575         for (; ref_map; ref_map = ref_map->next) {
 576                 if (!ref_map->peer_ref)
 577                         continue;
 578                 posn = &ref_map->next;
 579                 while (*posn) {
 580                         if ((*posn)->peer_ref &&
 581                             !strcmp((*posn)->peer_ref->name,
 582                                     ref_map->peer_ref->name)) {
 583                                 if (strcmp((*posn)->name, ref_map->name))
 584                                         die("%s tracks both %s and %s",
 585                                             ref_map->peer_ref->name,
 586                                             (*posn)->name, ref_map->name);
 587                                 next = (*posn)->next;
 588                                 free((*posn)->peer_ref);
 589                                 free(*posn);
 590                                 *posn = next;
 591                         } else {
 592                                 posn = &(*posn)->next;
 593                         }
 594                 }
 595         }
 596 }
 597
 598 int remote_has_url(struct remote *remote, const char *url)
 599 {
 600         int i;
 601         for (i = 0; i < remote->url_nr; i++) {
 602                 if (!strcmp(remote->url[i], url))
 603                         return 1;
 604         }
 605         return 0;
 606 }
 607
 608 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 609 {
 610         int find_src = refspec->src == NULL;
 611         char *needle, **result;
 612         int i;
 613
 614         if (find_src) {
 615                 if (!refspec->dst)
 616                         return error("find_tracking: need either src or dst");
 617                 needle = refspec->dst;
 618                 result = &refspec->src;
 619         } else {
 620                 needle = refspec->src;
 621                 result = &refspec->dst;
 622         }
 623
 624         for (i = 0; i < remote->fetch_refspec_nr; i++) {
 625                 struct refspec *fetch = &remote->fetch[i];
 626                 const char *key = find_src ? fetch->dst : fetch->src;
 627                 const char *value = find_src ? fetch->src : fetch->dst;
 628                 if (!fetch->dst)
 629                         continue;
 630                 if (fetch->pattern) {
 631                         if (!prefixcmp(needle, key) &&
 632                             needle[strlen(key)] == '/') {
 633                                 *result = xmalloc(strlen(value) +
 634                                                   strlen(needle) -
 635                                                   strlen(key) + 1);
 636                                 strcpy(*result, value);
 637                                 strcpy(*result + strlen(value),
 638                                        needle + strlen(key));
 639                                 refspec->force = fetch->force;
 640                                 return 0;
 641                         }
 642                 } else if (!strcmp(needle, key)) {
 643                         *result = xstrdup(value);
 644                         refspec->force = fetch->force;
 645                         return 0;
 646                 }
 647         }
 648         return -1;
 649 }
 650
 651 struct ref *alloc_ref(unsigned namelen)
 652 {
 653         struct ref *ret = xmalloc(sizeof(struct ref) + namelen);
 654         memset(ret, 0, sizeof(struct ref) + namelen);
 655         return ret;
 656 }
 657
 658 static struct ref *copy_ref(const struct ref *ref)
 659 {
 660         struct ref *ret = xmalloc(sizeof(struct ref) + strlen(ref->name) + 1);
 661         memcpy(ret, ref, sizeof(struct ref) + strlen(ref->name) + 1);
 662         ret->next = NULL;
 663         return ret;
 664 }
 665
 666 struct ref *copy_ref_list(const struct ref *ref)
 667 {
 668         struct ref *ret = NULL;
 669         struct ref **tail = &ret;
 670         while (ref) {
 671                 *tail = copy_ref(ref);
 672                 ref = ref->next;
 673                 tail = &((*tail)->next);
 674         }
 675         return ret;
 676 }
 677
 678 void free_refs(struct ref *ref)
 679 {
 680         struct ref *next;
 681         while (ref) {
 682                 next = ref->next;
 683                 free(ref->peer_ref);
 684                 free(ref);
 685                 ref = next;
 686         }
 687 }
 688
 689 static int count_refspec_match(const char *pattern,
 690                                struct ref *refs,
 691                                struct ref **matched_ref)
 692 {
 693         int patlen = strlen(pattern);
 694         struct ref *matched_weak = NULL;
 695         struct ref *matched = NULL;
 696         int weak_match = 0;
 697         int match = 0;
 698
 699         for (weak_match = match = 0; refs; refs = refs->next) {
 700                 char *name = refs->name;
 701                 int namelen = strlen(name);
 702
 703                 if (!refname_match(pattern, name, ref_rev_parse_rules))
 704                         continue;
 705
 706                 /* A match is "weak" if it is with refs outside
 707                  * heads or tags, and did not specify the pattern
 708                  * in full (e.g. "refs/remotes/origin/master") or at
 709                  * least from the toplevel (e.g. "remotes/origin/master");
 710                  * otherwise "git push $URL master" would result in
 711                  * ambiguity between remotes/origin/master and heads/master
 712                  * at the remote site.
 713                  */
 714                 if (namelen != patlen &&
 715                     patlen != namelen - 5 &&
 716                     prefixcmp(name, "refs/heads/") &&
 717                     prefixcmp(name, "refs/tags/")) {
 718                         /* We want to catch the case where only weak
 719                          * matches are found and there are multiple
 720                          * matches, and where more than one strong
 721                          * matches are found, as ambiguous.  One
 722                          * strong match with zero or more weak matches
 723                          * are acceptable as a unique match.
 724                          */
 725                         matched_weak = refs;
 726                         weak_match++;
 727                 }
 728                 else {
 729                         matched = refs;
 730                         match++;
 731                 }
 732         }
 733         if (!matched) {
 734                 *matched_ref = matched_weak;
 735                 return weak_match;
 736         }
 737         else {
 738                 *matched_ref = matched;
 739                 return match;
 740         }
 741 }
 742
 743 static void tail_link_ref(struct ref *ref, struct ref ***tail)
 744 {
 745         **tail = ref;
 746         while (ref->next)
 747                 ref = ref->next;
 748         *tail = &ref->next;
 749 }
 750
 751 static struct ref *try_explicit_object_name(const char *name)
 752 {
 753         unsigned char sha1[20];
 754         struct ref *ref;
 755         int len;
 756
 757         if (!*name) {
 758                 ref = alloc_ref(20);
 759                 strcpy(ref->name, "(delete)");
 760                 hashclr(ref->new_sha1);
 761                 return ref;
 762         }
 763         if (get_sha1(name, sha1))
 764                 return NULL;
 765         len = strlen(name) + 1;
 766         ref = alloc_ref(len);
 767         memcpy(ref->name, name, len);
 768         hashcpy(ref->new_sha1, sha1);
 769         return ref;
 770 }
 771
 772 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
 773 {
 774         struct ref *ret;
 775         size_t len;
 776
 777         len = strlen(name) + 1;
 778         ret = alloc_ref(len);
 779         memcpy(ret->name, name, len);
 780         tail_link_ref(ret, tail);
 781         return ret;
 782 }
 783
 784 static int match_explicit(struct ref *src, struct ref *dst,
 785                           struct ref ***dst_tail,
 786                           struct refspec *rs,
 787                           int errs)
 788 {
 789         struct ref *matched_src, *matched_dst;
 790
 791         const char *dst_value = rs->dst;
 792
 793         if (rs->pattern)
 794                 return errs;
 795
 796         matched_src = matched_dst = NULL;
 797         switch (count_refspec_match(rs->src, src, &matched_src)) {
 798         case 1:
 799                 break;
 800         case 0:
 801                 /* The source could be in the get_sha1() format
 802                  * not a reference name.  :refs/other is a
 803                  * way to delete 'other' ref at the remote end.
 804                  */
 805                 matched_src = try_explicit_object_name(rs->src);
 806                 if (!matched_src)
 807                         error("src refspec %s does not match any.", rs->src);
 808                 break;
 809         default:
 810                 matched_src = NULL;
 811                 error("src refspec %s matches more than one.", rs->src);
 812                 break;
 813         }
 814
 815         if (!matched_src)
 816                 errs = 1;
 817
 818         if (!dst_value) {
 819                 unsigned char sha1[20];
 820                 int flag;
 821
 822                 if (!matched_src)
 823                         return errs;
 824                 dst_value = resolve_ref(matched_src->name, sha1, 1, &flag);
 825                 if (!dst_value ||
 826                     ((flag & REF_ISSYMREF) &&
 827                      prefixcmp(dst_value, "refs/heads/")))
 828                         die("%s cannot be resolved to branch.",
 829                             matched_src->name);
 830         }
 831
 832         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
 833         case 1:
 834                 break;
 835         case 0:
 836                 if (!memcmp(dst_value, "refs/", 5))
 837                         matched_dst = make_linked_ref(dst_value, dst_tail);
 838                 else
 839                         error("dst refspec %s does not match any "
 840                               "existing ref on the remote and does "
 841                               "not start with refs/.", dst_value);
 842                 break;
 843         default:
 844                 matched_dst = NULL;
 845                 error("dst refspec %s matches more than one.",
 846                       dst_value);
 847                 break;
 848         }
 849         if (errs || !matched_dst)
 850                 return 1;
 851         if (matched_dst->peer_ref) {
 852                 errs = 1;
 853                 error("dst ref %s receives from more than one src.",
 854                       matched_dst->name);
 855         }
 856         else {
 857                 matched_dst->peer_ref = matched_src;
 858                 matched_dst->force = rs->force;
 859         }
 860         return errs;
 861 }
 862
 863 static int match_explicit_refs(struct ref *src, struct ref *dst,
 864                                struct ref ***dst_tail, struct refspec *rs,
 865                                int rs_nr)
 866 {
 867         int i, errs;
 868         for (i = errs = 0; i < rs_nr; i++)
 869                 errs |= match_explicit(src, dst, dst_tail, &rs[i], errs);
 870         return -errs;
 871 }
 872
 873 static const struct refspec *check_pattern_match(const struct refspec *rs,
 874                                                  int rs_nr,
 875                                                  const struct ref *src)
 876 {
 877         int i;
 878         for (i = 0; i < rs_nr; i++) {
 879                 if (rs[i].pattern &&
 880                     !prefixcmp(src->name, rs[i].src) &&
 881                     src->name[strlen(rs[i].src)] == '/')
 882                         return rs + i;
 883         }
 884         return NULL;
 885 }
 886
 887 /*
 888  * Note. This is used only by "push"; refspec matching rules for
 889  * push and fetch are subtly different, so do not try to reuse it
 890  * without thinking.
 891  */
 892 int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
 893                int nr_refspec, const char **refspec, int flags)
 894 {
 895         struct refspec *rs =
 896                 parse_push_refspec(nr_refspec, (const char **) refspec);
 897         int send_all = flags & MATCH_REFS_ALL;
 898         int send_mirror = flags & MATCH_REFS_MIRROR;
 899
 900         if (match_explicit_refs(src, dst, dst_tail, rs, nr_refspec))
 901                 return -1;
 902
 903         /* pick the remainder */
 904         for ( ; src; src = src->next) {
 905                 struct ref *dst_peer;
 906                 const struct refspec *pat = NULL;
 907                 char *dst_name;
 908                 if (src->peer_ref)
 909                         continue;
 910                 if (nr_refspec) {
 911                         pat = check_pattern_match(rs, nr_refspec, src);
 912                         if (!pat)
 913                                 continue;
 914                 }
 915                 else if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
 916                         /*
 917                          * "matching refs"; traditionally we pushed everything
 918                          * including refs outside refs/heads/ hierarchy, but
 919                          * that does not make much sense these days.
 920                          */
 921                         continue;
 922
 923                 if (pat) {
 924                         const char *dst_side = pat->dst ? pat->dst : pat->src;
 925                         dst_name = xmalloc(strlen(dst_side) +
 926                                            strlen(src->name) -
 927                                            strlen(pat->src) + 2);
 928                         strcpy(dst_name, dst_side);
 929                         strcat(dst_name, src->name + strlen(pat->src));
 930                 } else
 931                         dst_name = xstrdup(src->name);
 932                 dst_peer = find_ref_by_name(dst, dst_name);
 933                 if (dst_peer && dst_peer->peer_ref)
 934                         /* We're already sending something to this ref. */
 935                         goto free_name;
 936
 937                 if (!dst_peer && !nr_refspec && !(send_all || send_mirror))
 938                         /*
 939                          * Remote doesn't have it, and we have no
 940                          * explicit pattern, and we don't have
 941                          * --all nor --mirror.
 942                          */
 943                         goto free_name;
 944                 if (!dst_peer) {
 945                         /* Create a new one and link it */
 946                         dst_peer = make_linked_ref(dst_name, dst_tail);
 947                         hashcpy(dst_peer->new_sha1, src->new_sha1);
 948                 }
 949                 dst_peer->peer_ref = src;
 950                 if (pat)
 951                         dst_peer->force = pat->force;
 952         free_name:
 953                 free(dst_name);
 954         }
 955         return 0;
 956 }
 957
 958 struct branch *branch_get(const char *name)
 959 {
 960         struct branch *ret;
 961
 962         read_config();
 963         if (!name || !*name || !strcmp(name, "HEAD"))
 964                 ret = current_branch;
 965         else
 966                 ret = make_branch(name, 0);
 967         if (ret && ret->remote_name) {
 968                 ret->remote = remote_get(ret->remote_name);
 969                 if (ret->merge_nr) {
 970                         int i;
 971                         ret->merge = xcalloc(sizeof(*ret->merge),
 972                                              ret->merge_nr);
 973                         for (i = 0; i < ret->merge_nr; i++) {
 974                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
 975                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
 976                                 remote_find_tracking(ret->remote,
 977                                                      ret->merge[i]);
 978                         }
 979                 }
 980         }
 981         return ret;
 982 }
 983
 984 int branch_has_merge_config(struct branch *branch)
 985 {
 986         return branch && !!branch->merge;
 987 }
 988
 989 int branch_merge_matches(struct branch *branch,
 990                                  int i,
 991                                  const char *refname)
 992 {
 993         if (!branch || i < 0 || i >= branch->merge_nr)
 994                 return 0;
 995         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
 996 }
 997
 998 static struct ref *get_expanded_map(const struct ref *remote_refs,
 999                                     const struct refspec *refspec)
1000 {
1001         const struct ref *ref;
1002         struct ref *ret = NULL;
1003         struct ref **tail = &ret;
1004
1005         int remote_prefix_len = strlen(refspec->src);
1006         int local_prefix_len = strlen(refspec->dst);
1007
1008         for (ref = remote_refs; ref; ref = ref->next) {
1009                 if (strchr(ref->name, '^'))
1010                         continue; /* a dereference item */
1011                 if (!prefixcmp(ref->name, refspec->src)) {
1012                         const char *match;
1013                         struct ref *cpy = copy_ref(ref);
1014                         match = ref->name + remote_prefix_len;
1015
1016                         cpy->peer_ref = alloc_ref(local_prefix_len +
1017                                                   strlen(match) + 1);
1018                         sprintf(cpy->peer_ref->name, "%s%s",
1019                                 refspec->dst, match);
1020                         if (refspec->force)
1021                                 cpy->peer_ref->force = 1;
1022                         *tail = cpy;
1023                         tail = &cpy->next;
1024                 }
1025         }
1026
1027         return ret;
1028 }
1029
1030 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1031 {
1032         const struct ref *ref;
1033         for (ref = refs; ref; ref = ref->next) {
1034                 if (refname_match(name, ref->name, ref_fetch_rules))
1035                         return ref;
1036         }
1037         return NULL;
1038 }
1039
1040 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1041 {
1042         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1043
1044         if (!ref)
1045                 return NULL;
1046
1047         return copy_ref(ref);
1048 }
1049
1050 static struct ref *get_local_ref(const char *name)
1051 {
1052         struct ref *ret;
1053         if (!name)
1054                 return NULL;
1055
1056         if (!prefixcmp(name, "refs/")) {
1057                 ret = alloc_ref(strlen(name) + 1);
1058                 strcpy(ret->name, name);
1059                 return ret;
1060         }
1061
1062         if (!prefixcmp(name, "heads/") ||
1063             !prefixcmp(name, "tags/") ||
1064             !prefixcmp(name, "remotes/")) {
1065                 ret = alloc_ref(strlen(name) + 6);
1066                 sprintf(ret->name, "refs/%s", name);
1067                 return ret;
1068         }
1069
1070         ret = alloc_ref(strlen(name) + 12);
1071         sprintf(ret->name, "refs/heads/%s", name);
1072         return ret;
1073 }
1074
1075 int get_fetch_map(const struct ref *remote_refs,
1076                   const struct refspec *refspec,
1077                   struct ref ***tail,
1078                   int missing_ok)
1079 {
1080         struct ref *ref_map, **rmp;
1081
1082         if (refspec->pattern) {
1083                 ref_map = get_expanded_map(remote_refs, refspec);
1084         } else {
1085                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1086
1087                 ref_map = get_remote_ref(remote_refs, name);
1088                 if (!missing_ok && !ref_map)
1089                         die("Couldn't find remote ref %s", name);
1090                 if (ref_map) {
1091                         ref_map->peer_ref = get_local_ref(refspec->dst);
1092                         if (ref_map->peer_ref && refspec->force)
1093                                 ref_map->peer_ref->force = 1;
1094                 }
1095         }
1096
1097         for (rmp = &ref_map; *rmp; ) {
1098                 if ((*rmp)->peer_ref) {
1099                         int st = check_ref_format((*rmp)->peer_ref->name + 5);
1100                         if (st && st != CHECK_REF_FORMAT_ONELEVEL) {
1101                                 struct ref *ignore = *rmp;
1102                                 error("* Ignoring funny ref '%s' locally",
1103                                       (*rmp)->peer_ref->name);
1104                                 *rmp = (*rmp)->next;
1105                                 free(ignore->peer_ref);
1106                                 free(ignore);
1107                                 continue;
1108                         }
1109                 }
1110                 rmp = &((*rmp)->next);
1111         }
1112
1113         if (ref_map)
1114                 tail_link_ref(ref_map, tail);
1115
1116         return 0;
1117 }