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         struct strbuf 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
 262         /*
 263          * With "slash", e.g. "git fetch jgarzik/netdev-2.6" when
 264          * reading from $GIT_DIR/branches/jgarzik fetches "HEAD" from
 265          * the partial URL obtained from the branches file plus
 266          * "/netdev-2.6" and does not store it in any tracking ref.
 267          * #branch specifier in the file is ignored.
 268          *
 269          * Otherwise, the branches file would have URL and optionally
 270          * #branch specified.  The "master" (or specified) branch is
 271          * fetched and stored in the local branch of the same name.
 272          */
 273         strbuf_init(&branch, 0);
 274         frag = strchr(p, '#');
 275         if (frag) {
 276                 *(frag++) = '\0';
 277                 strbuf_addf(&branch, "refs/heads/%s", frag);
 278         } else
 279                 strbuf_addstr(&branch, "refs/heads/master");
 280         if (!slash) {
 281                 strbuf_addf(&branch, ":refs/heads/%s", remote->name);
 282         } else {
 283                 strbuf_reset(&branch);
 284                 strbuf_addstr(&branch, "HEAD:");
 285         }
 286         add_url_alias(remote, p);
 287         add_fetch_refspec(remote, strbuf_detach(&branch, 0));
 288         remote->fetch_tags = 1; /* always auto-follow */
 289 }
 290
 291 static int handle_config(const char *key, const char *value)
 292 {
 293         const char *name;
 294         const char *subkey;
 295         struct remote *remote;
 296         struct branch *branch;
 297         if (!prefixcmp(key, "branch.")) {
 298                 name = key + 7;
 299                 subkey = strrchr(name, '.');
 300                 if (!subkey)
 301                         return 0;
 302                 branch = make_branch(name, subkey - name);
 303                 if (!strcmp(subkey, ".remote")) {
 304                         if (!value)
 305                                 return config_error_nonbool(key);
 306                         branch->remote_name = xstrdup(value);
 307                         if (branch == current_branch)
 308                                 default_remote_name = branch->remote_name;
 309                 } else if (!strcmp(subkey, ".merge")) {
 310                         if (!value)
 311                                 return config_error_nonbool(key);
 312                         add_merge(branch, xstrdup(value));
 313                 }
 314                 return 0;
 315         }
 316         if (!prefixcmp(key, "url.")) {
 317                 struct rewrite *rewrite;
 318                 name = key + 4;
 319                 subkey = strrchr(name, '.');
 320                 if (!subkey)
 321                         return 0;
 322                 rewrite = make_rewrite(name, subkey - name);
 323                 if (!strcmp(subkey, ".insteadof")) {
 324                         if (!value)
 325                                 return config_error_nonbool(key);
 326                         add_instead_of(rewrite, xstrdup(value));
 327                 }
 328         }
 329         if (prefixcmp(key,  "remote."))
 330                 return 0;
 331         name = key + 7;
 332         subkey = strrchr(name, '.');
 333         if (!subkey)
 334                 return error("Config with no key for remote %s", name);
 335         if (*subkey == '/') {
 336                 warning("Config remote shorthand cannot begin with '/': %s", name);
 337                 return 0;
 338         }
 339         remote = make_remote(name, subkey - name);
 340         if (!strcmp(subkey, ".mirror"))
 341                 remote->mirror = git_config_bool(key, value);
 342         else if (!strcmp(subkey, ".skipdefaultupdate"))
 343                 remote->skip_default_update = git_config_bool(key, value);
 344
 345         else if (!strcmp(subkey, ".url")) {
 346                 const char *v;
 347                 if (git_config_string(&v, key, value))
 348                         return -1;
 349                 add_url(remote, v);
 350         } else if (!strcmp(subkey, ".push")) {
 351                 const char *v;
 352                 if (git_config_string(&v, key, value))
 353                         return -1;
 354                 add_push_refspec(remote, v);
 355         } else if (!strcmp(subkey, ".fetch")) {
 356                 const char *v;
 357                 if (git_config_string(&v, key, value))
 358                         return -1;
 359                 add_fetch_refspec(remote, v);
 360         } else if (!strcmp(subkey, ".receivepack")) {
 361                 const char *v;
 362                 if (git_config_string(&v, key, value))
 363                         return -1;
 364                 if (!remote->receivepack)
 365                         remote->receivepack = v;
 366                 else
 367                         error("more than one receivepack given, using the first");
 368         } else if (!strcmp(subkey, ".uploadpack")) {
 369                 const char *v;
 370                 if (git_config_string(&v, key, value))
 371                         return -1;
 372                 if (!remote->uploadpack)
 373                         remote->uploadpack = v;
 374                 else
 375                         error("more than one uploadpack given, using the first");
 376         } else if (!strcmp(subkey, ".tagopt")) {
 377                 if (!strcmp(value, "--no-tags"))
 378                         remote->fetch_tags = -1;
 379         } else if (!strcmp(subkey, ".proxy")) {
 380                 return git_config_string((const char **)&remote->http_proxy,
 381                                          key, value);
 382         }
 383         return 0;
 384 }
 385
 386 static void alias_all_urls(void)
 387 {
 388         int i, j;
 389         for (i = 0; i < remotes_nr; i++) {
 390                 if (!remotes[i])
 391                         continue;
 392                 for (j = 0; j < remotes[i]->url_nr; j++) {
 393                         remotes[i]->url[j] = alias_url(remotes[i]->url[j]);
 394                 }
 395         }
 396 }
 397
 398 static void read_config(void)
 399 {
 400         unsigned char sha1[20];
 401         const char *head_ref;
 402         int flag;
 403         if (default_remote_name) // did this already
 404                 return;
 405         default_remote_name = xstrdup("origin");
 406         current_branch = NULL;
 407         head_ref = resolve_ref("HEAD", sha1, 0, &flag);
 408         if (head_ref && (flag & REF_ISSYMREF) &&
 409             !prefixcmp(head_ref, "refs/heads/")) {
 410                 current_branch =
 411                         make_branch(head_ref + strlen("refs/heads/"), 0);
 412         }
 413         git_config(handle_config);
 414         alias_all_urls();
 415 }
 416
 417 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 418 {
 419         int i;
 420         int st;
 421         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 422
 423         for (i = 0; i < nr_refspec; i++) {
 424                 size_t llen, rlen;
 425                 int is_glob;
 426                 const char *lhs, *rhs;
 427
 428                 llen = rlen = is_glob = 0;
 429
 430                 lhs = refspec[i];
 431                 if (*lhs == '+') {
 432                         rs[i].force = 1;
 433                         lhs++;
 434                 }
 435
 436                 rhs = strrchr(lhs, ':');
 437                 if (rhs) {
 438                         rhs++;
 439                         rlen = strlen(rhs);
 440                         is_glob = (2 <= rlen && !strcmp(rhs + rlen - 2, "/*"));
 441                         if (is_glob)
 442                                 rlen -= 2;
 443                         rs[i].dst = xstrndup(rhs, rlen);
 444                 }
 445
 446                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 447                 if (2 <= llen && !memcmp(lhs + llen - 2, "/*", 2)) {
 448                         if ((rhs && !is_glob) || (!rhs && fetch))
 449                                 goto invalid;
 450                         is_glob = 1;
 451                         llen -= 2;
 452                 } else if (rhs && is_glob) {
 453                         goto invalid;
 454                 }
 455
 456                 rs[i].pattern = is_glob;
 457                 rs[i].src = xstrndup(lhs, llen);
 458
 459                 if (fetch) {
 460                         /*
 461                          * LHS
 462                          * - empty is allowed; it means HEAD.
 463                          * - otherwise it must be a valid looking ref.
 464                          */
 465                         if (!*rs[i].src)
 466                                 ; /* empty is ok */
 467                         else {
 468                                 st = check_ref_format(rs[i].src);
 469                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 470                                         goto invalid;
 471                         }
 472                         /*
 473                          * RHS
 474                          * - missing is ok, and is same as empty.
 475                          * - empty is ok; it means not to store.
 476                          * - otherwise it must be a valid looking ref.
 477                          */
 478                         if (!rs[i].dst) {
 479                                 ; /* ok */
 480                         } else if (!*rs[i].dst) {
 481                                 ; /* ok */
 482                         } else {
 483                                 st = check_ref_format(rs[i].dst);
 484                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 485                                         goto invalid;
 486                         }
 487                 } else {
 488                         /*
 489                          * LHS
 490                          * - empty is allowed; it means delete.
 491                          * - when wildcarded, it must be a valid looking ref.
 492                          * - otherwise, it must be an extended SHA-1, but
 493                          *   there is no existing way to validate this.
 494                          */
 495                         if (!*rs[i].src)
 496                                 ; /* empty is ok */
 497                         else if (is_glob) {
 498                                 st = check_ref_format(rs[i].src);
 499                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 500                                         goto invalid;
 501                         }
 502                         else
 503                                 ; /* anything goes, for now */
 504                         /*
 505                          * RHS
 506                          * - missing is allowed, but LHS then must be a
 507                          *   valid looking ref.
 508                          * - empty is not allowed.
 509                          * - otherwise it must be a valid looking ref.
 510                          */
 511                         if (!rs[i].dst) {
 512                                 st = check_ref_format(rs[i].src);
 513                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 514                                         goto invalid;
 515                         } else if (!*rs[i].dst) {
 516                                 goto invalid;
 517                         } else {
 518                                 st = check_ref_format(rs[i].dst);
 519                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 520                                         goto invalid;
 521                         }
 522                 }
 523         }
 524         return rs;
 525
 526  invalid:
 527         if (verify) {
 528                 free(rs);
 529                 return NULL;
 530         }
 531         die("Invalid refspec '%s'", refspec[i]);
 532 }
 533
 534 int valid_fetch_refspec(const char *fetch_refspec_str)
 535 {
 536         const char *fetch_refspec[] = { fetch_refspec_str };
 537         struct refspec *refspec;
 538
 539         refspec = parse_refspec_internal(1, fetch_refspec, 1, 1);
 540         if (refspec)
 541                 free(refspec);
 542         return !!refspec;
 543 }
 544
 545 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 546 {
 547         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 548 }
 549
 550 struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 551 {
 552         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 553 }
 554
 555 static int valid_remote_nick(const char *name)
 556 {
 557         if (!name[0] || /* not empty */
 558             (name[0] == '.' && /* not "." */
 559              (!name[1] || /* not ".." */
 560               (name[1] == '.' && !name[2]))))
 561                 return 0;
 562         return !strchr(name, '/'); /* no slash */
 563 }
 564
 565 struct remote *remote_get(const char *name)
 566 {
 567         struct remote *ret;
 568
 569         read_config();
 570         if (!name)
 571                 name = default_remote_name;
 572         ret = make_remote(name, 0);
 573         if (valid_remote_nick(name)) {
 574                 if (!ret->url)
 575                         read_remotes_file(ret);
 576                 if (!ret->url)
 577                         read_branches_file(ret);
 578         }
 579         if (!ret->url)
 580                 add_url_alias(ret, name);
 581         if (!ret->url)
 582                 return NULL;
 583         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 584         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 585         return ret;
 586 }
 587
 588 int for_each_remote(each_remote_fn fn, void *priv)
 589 {
 590         int i, result = 0;
 591         read_config();
 592         for (i = 0; i < remotes_nr && !result; i++) {
 593                 struct remote *r = remotes[i];
 594                 if (!r)
 595                         continue;
 596                 if (!r->fetch)
 597                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 598                                                        r->fetch_refspec);
 599                 if (!r->push)
 600                         r->push = parse_push_refspec(r->push_refspec_nr,
 601                                                      r->push_refspec);
 602                 result = fn(r, priv);
 603         }
 604         return result;
 605 }
 606
 607 void ref_remove_duplicates(struct ref *ref_map)
 608 {
 609         struct ref **posn;
 610         struct ref *next;
 611         for (; ref_map; ref_map = ref_map->next) {
 612                 if (!ref_map->peer_ref)
 613                         continue;
 614                 posn = &ref_map->next;
 615                 while (*posn) {
 616                         if ((*posn)->peer_ref &&
 617                             !strcmp((*posn)->peer_ref->name,
 618                                     ref_map->peer_ref->name)) {
 619                                 if (strcmp((*posn)->name, ref_map->name))
 620                                         die("%s tracks both %s and %s",
 621                                             ref_map->peer_ref->name,
 622                                             (*posn)->name, ref_map->name);
 623                                 next = (*posn)->next;
 624                                 free((*posn)->peer_ref);
 625                                 free(*posn);
 626                                 *posn = next;
 627                         } else {
 628                                 posn = &(*posn)->next;
 629                         }
 630                 }
 631         }
 632 }
 633
 634 int remote_has_url(struct remote *remote, const char *url)
 635 {
 636         int i;
 637         for (i = 0; i < remote->url_nr; i++) {
 638                 if (!strcmp(remote->url[i], url))
 639                         return 1;
 640         }
 641         return 0;
 642 }
 643
 644 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 645 {
 646         int find_src = refspec->src == NULL;
 647         char *needle, **result;
 648         int i;
 649
 650         if (find_src) {
 651                 if (!refspec->dst)
 652                         return error("find_tracking: need either src or dst");
 653                 needle = refspec->dst;
 654                 result = &refspec->src;
 655         } else {
 656                 needle = refspec->src;
 657                 result = &refspec->dst;
 658         }
 659
 660         for (i = 0; i < remote->fetch_refspec_nr; i++) {
 661                 struct refspec *fetch = &remote->fetch[i];
 662                 const char *key = find_src ? fetch->dst : fetch->src;
 663                 const char *value = find_src ? fetch->src : fetch->dst;
 664                 if (!fetch->dst)
 665                         continue;
 666                 if (fetch->pattern) {
 667                         if (!prefixcmp(needle, key) &&
 668                             needle[strlen(key)] == '/') {
 669                                 *result = xmalloc(strlen(value) +
 670                                                   strlen(needle) -
 671                                                   strlen(key) + 1);
 672                                 strcpy(*result, value);
 673                                 strcpy(*result + strlen(value),
 674                                        needle + strlen(key));
 675                                 refspec->force = fetch->force;
 676                                 return 0;
 677                         }
 678                 } else if (!strcmp(needle, key)) {
 679                         *result = xstrdup(value);
 680                         refspec->force = fetch->force;
 681                         return 0;
 682                 }
 683         }
 684         return -1;
 685 }
 686
 687 struct ref *alloc_ref(unsigned namelen)
 688 {
 689         struct ref *ret = xmalloc(sizeof(struct ref) + namelen);
 690         memset(ret, 0, sizeof(struct ref) + namelen);
 691         return ret;
 692 }
 693
 694 static struct ref *copy_ref(const struct ref *ref)
 695 {
 696         struct ref *ret = xmalloc(sizeof(struct ref) + strlen(ref->name) + 1);
 697         memcpy(ret, ref, sizeof(struct ref) + strlen(ref->name) + 1);
 698         ret->next = NULL;
 699         return ret;
 700 }
 701
 702 struct ref *copy_ref_list(const struct ref *ref)
 703 {
 704         struct ref *ret = NULL;
 705         struct ref **tail = &ret;
 706         while (ref) {
 707                 *tail = copy_ref(ref);
 708                 ref = ref->next;
 709                 tail = &((*tail)->next);
 710         }
 711         return ret;
 712 }
 713
 714 void free_refs(struct ref *ref)
 715 {
 716         struct ref *next;
 717         while (ref) {
 718                 next = ref->next;
 719                 free(ref->peer_ref);
 720                 free(ref);
 721                 ref = next;
 722         }
 723 }
 724
 725 static int count_refspec_match(const char *pattern,
 726                                struct ref *refs,
 727                                struct ref **matched_ref)
 728 {
 729         int patlen = strlen(pattern);
 730         struct ref *matched_weak = NULL;
 731         struct ref *matched = NULL;
 732         int weak_match = 0;
 733         int match = 0;
 734
 735         for (weak_match = match = 0; refs; refs = refs->next) {
 736                 char *name = refs->name;
 737                 int namelen = strlen(name);
 738
 739                 if (!refname_match(pattern, name, ref_rev_parse_rules))
 740                         continue;
 741
 742                 /* A match is "weak" if it is with refs outside
 743                  * heads or tags, and did not specify the pattern
 744                  * in full (e.g. "refs/remotes/origin/master") or at
 745                  * least from the toplevel (e.g. "remotes/origin/master");
 746                  * otherwise "git push $URL master" would result in
 747                  * ambiguity between remotes/origin/master and heads/master
 748                  * at the remote site.
 749                  */
 750                 if (namelen != patlen &&
 751                     patlen != namelen - 5 &&
 752                     prefixcmp(name, "refs/heads/") &&
 753                     prefixcmp(name, "refs/tags/")) {
 754                         /* We want to catch the case where only weak
 755                          * matches are found and there are multiple
 756                          * matches, and where more than one strong
 757                          * matches are found, as ambiguous.  One
 758                          * strong match with zero or more weak matches
 759                          * are acceptable as a unique match.
 760                          */
 761                         matched_weak = refs;
 762                         weak_match++;
 763                 }
 764                 else {
 765                         matched = refs;
 766                         match++;
 767                 }
 768         }
 769         if (!matched) {
 770                 *matched_ref = matched_weak;
 771                 return weak_match;
 772         }
 773         else {
 774                 *matched_ref = matched;
 775                 return match;
 776         }
 777 }
 778
 779 static void tail_link_ref(struct ref *ref, struct ref ***tail)
 780 {
 781         **tail = ref;
 782         while (ref->next)
 783                 ref = ref->next;
 784         *tail = &ref->next;
 785 }
 786
 787 static struct ref *try_explicit_object_name(const char *name)
 788 {
 789         unsigned char sha1[20];
 790         struct ref *ref;
 791         int len;
 792
 793         if (!*name) {
 794                 ref = alloc_ref(20);
 795                 strcpy(ref->name, "(delete)");
 796                 hashclr(ref->new_sha1);
 797                 return ref;
 798         }
 799         if (get_sha1(name, sha1))
 800                 return NULL;
 801         len = strlen(name) + 1;
 802         ref = alloc_ref(len);
 803         memcpy(ref->name, name, len);
 804         hashcpy(ref->new_sha1, sha1);
 805         return ref;
 806 }
 807
 808 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
 809 {
 810         struct ref *ret;
 811         size_t len;
 812
 813         len = strlen(name) + 1;
 814         ret = alloc_ref(len);
 815         memcpy(ret->name, name, len);
 816         tail_link_ref(ret, tail);
 817         return ret;
 818 }
 819
 820 static char *guess_ref(const char *name, struct ref *peer)
 821 {
 822         struct strbuf buf = STRBUF_INIT;
 823         unsigned char sha1[20];
 824
 825         const char *r = resolve_ref(peer->name, sha1, 1, NULL);
 826         if (!r)
 827                 return NULL;
 828
 829         if (!prefixcmp(r, "refs/heads/"))
 830                 strbuf_addstr(&buf, "refs/heads/");
 831         else if (!prefixcmp(r, "refs/tags/"))
 832                 strbuf_addstr(&buf, "refs/tags/");
 833         else
 834                 return NULL;
 835
 836         strbuf_addstr(&buf, name);
 837         return strbuf_detach(&buf, NULL);
 838 }
 839
 840 static int match_explicit(struct ref *src, struct ref *dst,
 841                           struct ref ***dst_tail,
 842                           struct refspec *rs,
 843                           int errs)
 844 {
 845         struct ref *matched_src, *matched_dst;
 846
 847         const char *dst_value = rs->dst;
 848         char *dst_guess;
 849
 850         if (rs->pattern)
 851                 return errs;
 852
 853         matched_src = matched_dst = NULL;
 854         switch (count_refspec_match(rs->src, src, &matched_src)) {
 855         case 1:
 856                 break;
 857         case 0:
 858                 /* The source could be in the get_sha1() format
 859                  * not a reference name.  :refs/other is a
 860                  * way to delete 'other' ref at the remote end.
 861                  */
 862                 matched_src = try_explicit_object_name(rs->src);
 863                 if (!matched_src)
 864                         error("src refspec %s does not match any.", rs->src);
 865                 break;
 866         default:
 867                 matched_src = NULL;
 868                 error("src refspec %s matches more than one.", rs->src);
 869                 break;
 870         }
 871
 872         if (!matched_src)
 873                 errs = 1;
 874
 875         if (!dst_value) {
 876                 unsigned char sha1[20];
 877                 int flag;
 878
 879                 if (!matched_src)
 880                         return errs;
 881                 dst_value = resolve_ref(matched_src->name, sha1, 1, &flag);
 882                 if (!dst_value ||
 883                     ((flag & REF_ISSYMREF) &&
 884                      prefixcmp(dst_value, "refs/heads/")))
 885                         die("%s cannot be resolved to branch.",
 886                             matched_src->name);
 887         }
 888
 889         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
 890         case 1:
 891                 break;
 892         case 0:
 893                 if (!memcmp(dst_value, "refs/", 5))
 894                         matched_dst = make_linked_ref(dst_value, dst_tail);
 895                 else if((dst_guess = guess_ref(dst_value, matched_src)))
 896                         matched_dst = make_linked_ref(dst_guess, dst_tail);
 897                 else
 898                         error("unable to push to unqualified destination: %s\n"
 899                               "The destination refspec neither matches an "
 900                               "existing ref on the remote nor\n"
 901                               "begins with refs/, and we are unable to "
 902                               "guess a prefix based on the source ref.",
 903                               dst_value);
 904                 break;
 905         default:
 906                 matched_dst = NULL;
 907                 error("dst refspec %s matches more than one.",
 908                       dst_value);
 909                 break;
 910         }
 911         if (errs || !matched_dst)
 912                 return 1;
 913         if (matched_dst->peer_ref) {
 914                 errs = 1;
 915                 error("dst ref %s receives from more than one src.",
 916                       matched_dst->name);
 917         }
 918         else {
 919                 matched_dst->peer_ref = matched_src;
 920                 matched_dst->force = rs->force;
 921         }
 922         return errs;
 923 }
 924
 925 static int match_explicit_refs(struct ref *src, struct ref *dst,
 926                                struct ref ***dst_tail, struct refspec *rs,
 927                                int rs_nr)
 928 {
 929         int i, errs;
 930         for (i = errs = 0; i < rs_nr; i++)
 931                 errs |= match_explicit(src, dst, dst_tail, &rs[i], errs);
 932         return -errs;
 933 }
 934
 935 static const struct refspec *check_pattern_match(const struct refspec *rs,
 936                                                  int rs_nr,
 937                                                  const struct ref *src)
 938 {
 939         int i;
 940         for (i = 0; i < rs_nr; i++) {
 941                 if (rs[i].pattern &&
 942                     !prefixcmp(src->name, rs[i].src) &&
 943                     src->name[strlen(rs[i].src)] == '/')
 944                         return rs + i;
 945         }
 946         return NULL;
 947 }
 948
 949 /*
 950  * Note. This is used only by "push"; refspec matching rules for
 951  * push and fetch are subtly different, so do not try to reuse it
 952  * without thinking.
 953  */
 954 int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
 955                int nr_refspec, const char **refspec, int flags)
 956 {
 957         struct refspec *rs =
 958                 parse_push_refspec(nr_refspec, (const char **) refspec);
 959         int send_all = flags & MATCH_REFS_ALL;
 960         int send_mirror = flags & MATCH_REFS_MIRROR;
 961
 962         if (match_explicit_refs(src, dst, dst_tail, rs, nr_refspec))
 963                 return -1;
 964
 965         /* pick the remainder */
 966         for ( ; src; src = src->next) {
 967                 struct ref *dst_peer;
 968                 const struct refspec *pat = NULL;
 969                 char *dst_name;
 970                 if (src->peer_ref)
 971                         continue;
 972                 if (nr_refspec) {
 973                         pat = check_pattern_match(rs, nr_refspec, src);
 974                         if (!pat)
 975                                 continue;
 976                 }
 977                 else if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
 978                         /*
 979                          * "matching refs"; traditionally we pushed everything
 980                          * including refs outside refs/heads/ hierarchy, but
 981                          * that does not make much sense these days.
 982                          */
 983                         continue;
 984
 985                 if (pat) {
 986                         const char *dst_side = pat->dst ? pat->dst : pat->src;
 987                         dst_name = xmalloc(strlen(dst_side) +
 988                                            strlen(src->name) -
 989                                            strlen(pat->src) + 2);
 990                         strcpy(dst_name, dst_side);
 991                         strcat(dst_name, src->name + strlen(pat->src));
 992                 } else
 993                         dst_name = xstrdup(src->name);
 994                 dst_peer = find_ref_by_name(dst, dst_name);
 995                 if (dst_peer && dst_peer->peer_ref)
 996                         /* We're already sending something to this ref. */
 997                         goto free_name;
 998
 999                 if (!dst_peer && !nr_refspec && !(send_all || send_mirror))
1000                         /*
1001                          * Remote doesn't have it, and we have no
1002                          * explicit pattern, and we don't have
1003                          * --all nor --mirror.
1004                          */
1005                         goto free_name;
1006                 if (!dst_peer) {
1007                         /* Create a new one and link it */
1008                         dst_peer = make_linked_ref(dst_name, dst_tail);
1009                         hashcpy(dst_peer->new_sha1, src->new_sha1);
1010                 }
1011                 dst_peer->peer_ref = src;
1012                 if (pat)
1013                         dst_peer->force = pat->force;
1014         free_name:
1015                 free(dst_name);
1016         }
1017         return 0;
1018 }
1019
1020 struct branch *branch_get(const char *name)
1021 {
1022         struct branch *ret;
1023
1024         read_config();
1025         if (!name || !*name || !strcmp(name, "HEAD"))
1026                 ret = current_branch;
1027         else
1028                 ret = make_branch(name, 0);
1029         if (ret && ret->remote_name) {
1030                 ret->remote = remote_get(ret->remote_name);
1031                 if (ret->merge_nr) {
1032                         int i;
1033                         ret->merge = xcalloc(sizeof(*ret->merge),
1034                                              ret->merge_nr);
1035                         for (i = 0; i < ret->merge_nr; i++) {
1036                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1037                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1038                                 remote_find_tracking(ret->remote,
1039                                                      ret->merge[i]);
1040                         }
1041                 }
1042         }
1043         return ret;
1044 }
1045
1046 int branch_has_merge_config(struct branch *branch)
1047 {
1048         return branch && !!branch->merge;
1049 }
1050
1051 int branch_merge_matches(struct branch *branch,
1052                                  int i,
1053                                  const char *refname)
1054 {
1055         if (!branch || i < 0 || i >= branch->merge_nr)
1056                 return 0;
1057         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1058 }
1059
1060 static struct ref *get_expanded_map(const struct ref *remote_refs,
1061                                     const struct refspec *refspec)
1062 {
1063         const struct ref *ref;
1064         struct ref *ret = NULL;
1065         struct ref **tail = &ret;
1066
1067         int remote_prefix_len = strlen(refspec->src);
1068         int local_prefix_len = strlen(refspec->dst);
1069
1070         for (ref = remote_refs; ref; ref = ref->next) {
1071                 if (strchr(ref->name, '^'))
1072                         continue; /* a dereference item */
1073                 if (!prefixcmp(ref->name, refspec->src)) {
1074                         const char *match;
1075                         struct ref *cpy = copy_ref(ref);
1076                         match = ref->name + remote_prefix_len;
1077
1078                         cpy->peer_ref = alloc_ref(local_prefix_len +
1079                                                   strlen(match) + 1);
1080                         sprintf(cpy->peer_ref->name, "%s%s",
1081                                 refspec->dst, match);
1082                         if (refspec->force)
1083                                 cpy->peer_ref->force = 1;
1084                         *tail = cpy;
1085                         tail = &cpy->next;
1086                 }
1087         }
1088
1089         return ret;
1090 }
1091
1092 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1093 {
1094         const struct ref *ref;
1095         for (ref = refs; ref; ref = ref->next) {
1096                 if (refname_match(name, ref->name, ref_fetch_rules))
1097                         return ref;
1098         }
1099         return NULL;
1100 }
1101
1102 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1103 {
1104         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1105
1106         if (!ref)
1107                 return NULL;
1108
1109         return copy_ref(ref);
1110 }
1111
1112 static struct ref *get_local_ref(const char *name)
1113 {
1114         struct ref *ret;
1115         if (!name)
1116                 return NULL;
1117
1118         if (!prefixcmp(name, "refs/")) {
1119                 ret = alloc_ref(strlen(name) + 1);
1120                 strcpy(ret->name, name);
1121                 return ret;
1122         }
1123
1124         if (!prefixcmp(name, "heads/") ||
1125             !prefixcmp(name, "tags/") ||
1126             !prefixcmp(name, "remotes/")) {
1127                 ret = alloc_ref(strlen(name) + 6);
1128                 sprintf(ret->name, "refs/%s", name);
1129                 return ret;
1130         }
1131
1132         ret = alloc_ref(strlen(name) + 12);
1133         sprintf(ret->name, "refs/heads/%s", name);
1134         return ret;
1135 }
1136
1137 int get_fetch_map(const struct ref *remote_refs,
1138                   const struct refspec *refspec,
1139                   struct ref ***tail,
1140                   int missing_ok)
1141 {
1142         struct ref *ref_map, **rmp;
1143
1144         if (refspec->pattern) {
1145                 ref_map = get_expanded_map(remote_refs, refspec);
1146         } else {
1147                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1148
1149                 ref_map = get_remote_ref(remote_refs, name);
1150                 if (!missing_ok && !ref_map)
1151                         die("Couldn't find remote ref %s", name);
1152                 if (ref_map) {
1153                         ref_map->peer_ref = get_local_ref(refspec->dst);
1154                         if (ref_map->peer_ref && refspec->force)
1155                                 ref_map->peer_ref->force = 1;
1156                 }
1157         }
1158
1159         for (rmp = &ref_map; *rmp; ) {
1160                 if ((*rmp)->peer_ref) {
1161                         int st = check_ref_format((*rmp)->peer_ref->name + 5);
1162                         if (st && st != CHECK_REF_FORMAT_ONELEVEL) {
1163                                 struct ref *ignore = *rmp;
1164                                 error("* Ignoring funny ref '%s' locally",
1165                                       (*rmp)->peer_ref->name);
1166                                 *rmp = (*rmp)->next;
1167                                 free(ignore->peer_ref);
1168                                 free(ignore);
1169                                 continue;
1170                         }
1171                 }
1172                 rmp = &((*rmp)->next);
1173         }
1174
1175         if (ref_map)
1176                 tail_link_ref(ref_map, tail);
1177
1178         return 0;
1179 }