remote.c

   1 #include "cache.h"
   2 #include "remote.h"
   3 #include "refs.h"
   4 #include "commit.h"
   5 #include "diff.h"
   6 #include "revision.h"
   7 #include "dir.h"
   8 #include "tag.h"
   9 #include "string-list.h"
  10
  11 static struct refspec s_tag_refspec = {
  12         0,
  13         1,
  14         0,
  15         "refs/tags/*",
  16         "refs/tags/*"
  17 };
  18
  19 const struct refspec *tag_refspec = &s_tag_refspec;
  20
  21 struct counted_string {
  22         size_t len;
  23         const char *s;
  24 };
  25 struct rewrite {
  26         const char *base;
  27         size_t baselen;
  28         struct counted_string *instead_of;
  29         int instead_of_nr;
  30         int instead_of_alloc;
  31 };
  32 struct rewrites {
  33         struct rewrite **rewrite;
  34         int rewrite_alloc;
  35         int rewrite_nr;
  36 };
  37
  38 static struct remote **remotes;
  39 static int remotes_alloc;
  40 static int remotes_nr;
  41
  42 static struct branch **branches;
  43 static int branches_alloc;
  44 static int branches_nr;
  45
  46 static struct branch *current_branch;
  47 static const char *default_remote_name;
  48 static int explicit_default_remote_name;
  49
  50 static struct rewrites rewrites;
  51 static struct rewrites rewrites_push;
  52
  53 #define BUF_SIZE (2048)
  54 static char buffer[BUF_SIZE];
  55
  56 static int valid_remote(const struct remote *remote)
  57 {
  58         return (!!remote->url) || (!!remote->foreign_vcs);
  59 }
  60
  61 static const char *alias_url(const char *url, struct rewrites *r)
  62 {
  63         int i, j;
  64         char *ret;
  65         struct counted_string *longest;
  66         int longest_i;
  67
  68         longest = NULL;
  69         longest_i = -1;
  70         for (i = 0; i < r->rewrite_nr; i++) {
  71                 if (!r->rewrite[i])
  72                         continue;
  73                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  74                         if (!prefixcmp(url, r->rewrite[i]->instead_of[j].s) &&
  75                             (!longest ||
  76                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  77                                 longest = &(r->rewrite[i]->instead_of[j]);
  78                                 longest_i = i;
  79                         }
  80                 }
  81         }
  82         if (!longest)
  83                 return url;
  84
  85         ret = xmalloc(r->rewrite[longest_i]->baselen +
  86                      (strlen(url) - longest->len) + 1);
  87         strcpy(ret, r->rewrite[longest_i]->base);
  88         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
  89         return ret;
  90 }
  91
  92 static void add_push_refspec(struct remote *remote, const char *ref)
  93 {
  94         ALLOC_GROW(remote->push_refspec,
  95                    remote->push_refspec_nr + 1,
  96                    remote->push_refspec_alloc);
  97         remote->push_refspec[remote->push_refspec_nr++] = ref;
  98 }
  99
 100 static void add_fetch_refspec(struct remote *remote, const char *ref)
 101 {
 102         ALLOC_GROW(remote->fetch_refspec,
 103                    remote->fetch_refspec_nr + 1,
 104                    remote->fetch_refspec_alloc);
 105         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
 106 }
 107
 108 static void add_url(struct remote *remote, const char *url)
 109 {
 110         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
 111         remote->url[remote->url_nr++] = url;
 112 }
 113
 114 static void add_pushurl(struct remote *remote, const char *pushurl)
 115 {
 116         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
 117         remote->pushurl[remote->pushurl_nr++] = pushurl;
 118 }
 119
 120 static void add_pushurl_alias(struct remote *remote, const char *url)
 121 {
 122         const char *pushurl = alias_url(url, &rewrites_push);
 123         if (pushurl != url)
 124                 add_pushurl(remote, pushurl);
 125 }
 126
 127 static void add_url_alias(struct remote *remote, const char *url)
 128 {
 129         add_url(remote, alias_url(url, &rewrites));
 130         add_pushurl_alias(remote, url);
 131 }
 132
 133 static struct remote *make_remote(const char *name, int len)
 134 {
 135         struct remote *ret;
 136         int i;
 137
 138         for (i = 0; i < remotes_nr; i++) {
 139                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
 140                            !remotes[i]->name[len]) :
 141                     !strcmp(name, remotes[i]->name))
 142                         return remotes[i];
 143         }
 144
 145         ret = xcalloc(1, sizeof(struct remote));
 146         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 147         remotes[remotes_nr++] = ret;
 148         if (len)
 149                 ret->name = xstrndup(name, len);
 150         else
 151                 ret->name = xstrdup(name);
 152         return ret;
 153 }
 154
 155 static void add_merge(struct branch *branch, const char *name)
 156 {
 157         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 158                    branch->merge_alloc);
 159         branch->merge_name[branch->merge_nr++] = name;
 160 }
 161
 162 static struct branch *make_branch(const char *name, int len)
 163 {
 164         struct branch *ret;
 165         int i;
 166         char *refname;
 167
 168         for (i = 0; i < branches_nr; i++) {
 169                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 170                            !branches[i]->name[len]) :
 171                     !strcmp(name, branches[i]->name))
 172                         return branches[i];
 173         }
 174
 175         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 176         ret = xcalloc(1, sizeof(struct branch));
 177         branches[branches_nr++] = ret;
 178         if (len)
 179                 ret->name = xstrndup(name, len);
 180         else
 181                 ret->name = xstrdup(name);
 182         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
 183         strcpy(refname, "refs/heads/");
 184         strcpy(refname + strlen("refs/heads/"), ret->name);
 185         ret->refname = refname;
 186
 187         return ret;
 188 }
 189
 190 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 191 {
 192         struct rewrite *ret;
 193         int i;
 194
 195         for (i = 0; i < r->rewrite_nr; i++) {
 196                 if (len
 197                     ? (len == r->rewrite[i]->baselen &&
 198                        !strncmp(base, r->rewrite[i]->base, len))
 199                     : !strcmp(base, r->rewrite[i]->base))
 200                         return r->rewrite[i];
 201         }
 202
 203         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 204         ret = xcalloc(1, sizeof(struct rewrite));
 205         r->rewrite[r->rewrite_nr++] = ret;
 206         if (len) {
 207                 ret->base = xstrndup(base, len);
 208                 ret->baselen = len;
 209         }
 210         else {
 211                 ret->base = xstrdup(base);
 212                 ret->baselen = strlen(base);
 213         }
 214         return ret;
 215 }
 216
 217 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 218 {
 219         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 220         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 221         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 222         rewrite->instead_of_nr++;
 223 }
 224
 225 static void read_remotes_file(struct remote *remote)
 226 {
 227         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 228
 229         if (!f)
 230                 return;
 231         remote->origin = REMOTE_REMOTES;
 232         while (fgets(buffer, BUF_SIZE, f)) {
 233                 int value_list;
 234                 char *s, *p;
 235
 236                 if (!prefixcmp(buffer, "URL:")) {
 237                         value_list = 0;
 238                         s = buffer + 4;
 239                 } else if (!prefixcmp(buffer, "Push:")) {
 240                         value_list = 1;
 241                         s = buffer + 5;
 242                 } else if (!prefixcmp(buffer, "Pull:")) {
 243                         value_list = 2;
 244                         s = buffer + 5;
 245                 } else
 246                         continue;
 247
 248                 while (isspace(*s))
 249                         s++;
 250                 if (!*s)
 251                         continue;
 252
 253                 p = s + strlen(s);
 254                 while (isspace(p[-1]))
 255                         *--p = 0;
 256
 257                 switch (value_list) {
 258                 case 0:
 259                         add_url_alias(remote, xstrdup(s));
 260                         break;
 261                 case 1:
 262                         add_push_refspec(remote, xstrdup(s));
 263                         break;
 264                 case 2:
 265                         add_fetch_refspec(remote, xstrdup(s));
 266                         break;
 267                 }
 268         }
 269         fclose(f);
 270 }
 271
 272 static void read_branches_file(struct remote *remote)
 273 {
 274         const char *slash = strchr(remote->name, '/');
 275         char *frag;
 276         struct strbuf branch = STRBUF_INIT;
 277         int n = slash ? slash - remote->name : 1000;
 278         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
 279         char *s, *p;
 280         int len;
 281
 282         if (!f)
 283                 return;
 284         s = fgets(buffer, BUF_SIZE, f);
 285         fclose(f);
 286         if (!s)
 287                 return;
 288         while (isspace(*s))
 289                 s++;
 290         if (!*s)
 291                 return;
 292         remote->origin = REMOTE_BRANCHES;
 293         p = s + strlen(s);
 294         while (isspace(p[-1]))
 295                 *--p = 0;
 296         len = p - s;
 297         if (slash)
 298                 len += strlen(slash);
 299         p = xmalloc(len + 1);
 300         strcpy(p, s);
 301         if (slash)
 302                 strcat(p, slash);
 303
 304         /*
 305          * With "slash", e.g. "git fetch jgarzik/netdev-2.6" when
 306          * reading from $GIT_DIR/branches/jgarzik fetches "HEAD" from
 307          * the partial URL obtained from the branches file plus
 308          * "/netdev-2.6" and does not store it in any tracking ref.
 309          * #branch specifier in the file is ignored.
 310          *
 311          * Otherwise, the branches file would have URL and optionally
 312          * #branch specified.  The "master" (or specified) branch is
 313          * fetched and stored in the local branch of the same name.
 314          */
 315         frag = strchr(p, '#');
 316         if (frag) {
 317                 *(frag++) = '\0';
 318                 strbuf_addf(&branch, "refs/heads/%s", frag);
 319         } else
 320                 strbuf_addstr(&branch, "refs/heads/master");
 321         if (!slash) {
 322                 strbuf_addf(&branch, ":refs/heads/%s", remote->name);
 323         } else {
 324                 strbuf_reset(&branch);
 325                 strbuf_addstr(&branch, "HEAD:");
 326         }
 327         add_url_alias(remote, p);
 328         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
 329         /*
 330          * Cogito compatible push: push current HEAD to remote #branch
 331          * (master if missing)
 332          */
 333         strbuf_init(&branch, 0);
 334         strbuf_addstr(&branch, "HEAD");
 335         if (frag)
 336                 strbuf_addf(&branch, ":refs/heads/%s", frag);
 337         else
 338                 strbuf_addstr(&branch, ":refs/heads/master");
 339         add_push_refspec(remote, strbuf_detach(&branch, NULL));
 340         remote->fetch_tags = 1; /* always auto-follow */
 341 }
 342
 343 static int handle_config(const char *key, const char *value, void *cb)
 344 {
 345         const char *name;
 346         const char *subkey;
 347         struct remote *remote;
 348         struct branch *branch;
 349         if (!prefixcmp(key, "branch.")) {
 350                 name = key + 7;
 351                 subkey = strrchr(name, '.');
 352                 if (!subkey)
 353                         return 0;
 354                 branch = make_branch(name, subkey - name);
 355                 if (!strcmp(subkey, ".remote")) {
 356                         if (!value)
 357                                 return config_error_nonbool(key);
 358                         branch->remote_name = xstrdup(value);
 359                         if (branch == current_branch) {
 360                                 default_remote_name = branch->remote_name;
 361                                 explicit_default_remote_name = 1;
 362                         }
 363                 } else if (!strcmp(subkey, ".merge")) {
 364                         if (!value)
 365                                 return config_error_nonbool(key);
 366                         add_merge(branch, xstrdup(value));
 367                 }
 368                 return 0;
 369         }
 370         if (!prefixcmp(key, "url.")) {
 371                 struct rewrite *rewrite;
 372                 name = key + 4;
 373                 subkey = strrchr(name, '.');
 374                 if (!subkey)
 375                         return 0;
 376                 if (!strcmp(subkey, ".insteadof")) {
 377                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 378                         if (!value)
 379                                 return config_error_nonbool(key);
 380                         add_instead_of(rewrite, xstrdup(value));
 381                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 382                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 383                         if (!value)
 384                                 return config_error_nonbool(key);
 385                         add_instead_of(rewrite, xstrdup(value));
 386                 }
 387         }
 388         if (prefixcmp(key,  "remote."))
 389                 return 0;
 390         name = key + 7;
 391         if (*name == '/') {
 392                 warning("Config remote shorthand cannot begin with '/': %s",
 393                         name);
 394                 return 0;
 395         }
 396         subkey = strrchr(name, '.');
 397         if (!subkey)
 398                 return 0;
 399         remote = make_remote(name, subkey - name);
 400         remote->origin = REMOTE_CONFIG;
 401         if (!strcmp(subkey, ".mirror"))
 402                 remote->mirror = git_config_bool(key, value);
 403         else if (!strcmp(subkey, ".skipdefaultupdate"))
 404                 remote->skip_default_update = git_config_bool(key, value);
 405         else if (!strcmp(subkey, ".skipfetchall"))
 406                 remote->skip_default_update = git_config_bool(key, value);
 407         else if (!strcmp(subkey, ".url")) {
 408                 const char *v;
 409                 if (git_config_string(&v, key, value))
 410                         return -1;
 411                 add_url(remote, v);
 412         } else if (!strcmp(subkey, ".pushurl")) {
 413                 const char *v;
 414                 if (git_config_string(&v, key, value))
 415                         return -1;
 416                 add_pushurl(remote, v);
 417         } else if (!strcmp(subkey, ".push")) {
 418                 const char *v;
 419                 if (git_config_string(&v, key, value))
 420                         return -1;
 421                 add_push_refspec(remote, v);
 422         } else if (!strcmp(subkey, ".fetch")) {
 423                 const char *v;
 424                 if (git_config_string(&v, key, value))
 425                         return -1;
 426                 add_fetch_refspec(remote, v);
 427         } else if (!strcmp(subkey, ".receivepack")) {
 428                 const char *v;
 429                 if (git_config_string(&v, key, value))
 430                         return -1;
 431                 if (!remote->receivepack)
 432                         remote->receivepack = v;
 433                 else
 434                         error("more than one receivepack given, using the first");
 435         } else if (!strcmp(subkey, ".uploadpack")) {
 436                 const char *v;
 437                 if (git_config_string(&v, key, value))
 438                         return -1;
 439                 if (!remote->uploadpack)
 440                         remote->uploadpack = v;
 441                 else
 442                         error("more than one uploadpack given, using the first");
 443         } else if (!strcmp(subkey, ".tagopt")) {
 444                 if (!strcmp(value, "--no-tags"))
 445                         remote->fetch_tags = -1;
 446                 else if (!strcmp(value, "--tags"))
 447                         remote->fetch_tags = 2;
 448         } else if (!strcmp(subkey, ".proxy")) {
 449                 return git_config_string((const char **)&remote->http_proxy,
 450                                          key, value);
 451         } else if (!strcmp(subkey, ".vcs")) {
 452                 return git_config_string(&remote->foreign_vcs, key, value);
 453         }
 454         return 0;
 455 }
 456
 457 static void alias_all_urls(void)
 458 {
 459         int i, j;
 460         for (i = 0; i < remotes_nr; i++) {
 461                 int add_pushurl_aliases;
 462                 if (!remotes[i])
 463                         continue;
 464                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 465                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 466                 }
 467                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 468                 for (j = 0; j < remotes[i]->url_nr; j++) {
 469                         if (add_pushurl_aliases)
 470                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 471                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 472                 }
 473         }
 474 }
 475
 476 static void read_config(void)
 477 {
 478         unsigned char sha1[20];
 479         const char *head_ref;
 480         int flag;
 481         if (default_remote_name) /* did this already */
 482                 return;
 483         default_remote_name = xstrdup("origin");
 484         current_branch = NULL;
 485         head_ref = resolve_ref("HEAD", sha1, 0, &flag);
 486         if (head_ref && (flag & REF_ISSYMREF) &&
 487             !prefixcmp(head_ref, "refs/heads/")) {
 488                 current_branch =
 489                         make_branch(head_ref + strlen("refs/heads/"), 0);
 490         }
 491         git_config(handle_config, NULL);
 492         alias_all_urls();
 493 }
 494
 495 /*
 496  * We need to make sure the remote-tracking branches are well formed, but a
 497  * wildcard refspec in "struct refspec" must have a trailing slash. We
 498  * temporarily drop the trailing '/' while calling check_ref_format(),
 499  * and put it back.  The caller knows that a CHECK_REF_FORMAT_ONELEVEL
 500  * error return is Ok for a wildcard refspec.
 501  */
 502 static int verify_refname(char *name, int is_glob)
 503 {
 504         int result;
 505
 506         result = check_ref_format(name);
 507         if (is_glob && result == CHECK_REF_FORMAT_WILDCARD)
 508                 result = CHECK_REF_FORMAT_OK;
 509         return result;
 510 }
 511
 512 /*
 513  * This function frees a refspec array.
 514  * Warning: code paths should be checked to ensure that the src
 515  *          and dst pointers are always freeable pointers as well
 516  *          as the refspec pointer itself.
 517  */
 518 static void free_refspecs(struct refspec *refspec, int nr_refspec)
 519 {
 520         int i;
 521
 522         if (!refspec)
 523                 return;
 524
 525         for (i = 0; i < nr_refspec; i++) {
 526                 free(refspec[i].src);
 527                 free(refspec[i].dst);
 528         }
 529         free(refspec);
 530 }
 531
 532 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 533 {
 534         int i;
 535         int st;
 536         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 537
 538         for (i = 0; i < nr_refspec; i++) {
 539                 size_t llen;
 540                 int is_glob;
 541                 const char *lhs, *rhs;
 542
 543                 is_glob = 0;
 544
 545                 lhs = refspec[i];
 546                 if (*lhs == '+') {
 547                         rs[i].force = 1;
 548                         lhs++;
 549                 }
 550
 551                 rhs = strrchr(lhs, ':');
 552
 553                 /*
 554                  * Before going on, special case ":" (or "+:") as a refspec
 555                  * for matching refs.
 556                  */
 557                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
 558                         rs[i].matching = 1;
 559                         continue;
 560                 }
 561
 562                 if (rhs) {
 563                         size_t rlen = strlen(++rhs);
 564                         is_glob = (1 <= rlen && strchr(rhs, '*'));
 565                         rs[i].dst = xstrndup(rhs, rlen);
 566                 }
 567
 568                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 569                 if (1 <= llen && memchr(lhs, '*', llen)) {
 570                         if ((rhs && !is_glob) || (!rhs && fetch))
 571                                 goto invalid;
 572                         is_glob = 1;
 573                 } else if (rhs && is_glob) {
 574                         goto invalid;
 575                 }
 576
 577                 rs[i].pattern = is_glob;
 578                 rs[i].src = xstrndup(lhs, llen);
 579
 580                 if (fetch) {
 581                         /*
 582                          * LHS
 583                          * - empty is allowed; it means HEAD.
 584                          * - otherwise it must be a valid looking ref.
 585                          */
 586                         if (!*rs[i].src)
 587                                 ; /* empty is ok */
 588                         else {
 589                                 st = verify_refname(rs[i].src, is_glob);
 590                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 591                                         goto invalid;
 592                         }
 593                         /*
 594                          * RHS
 595                          * - missing is ok, and is same as empty.
 596                          * - empty is ok; it means not to store.
 597                          * - otherwise it must be a valid looking ref.
 598                          */
 599                         if (!rs[i].dst) {
 600                                 ; /* ok */
 601                         } else if (!*rs[i].dst) {
 602                                 ; /* ok */
 603                         } else {
 604                                 st = verify_refname(rs[i].dst, is_glob);
 605                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 606                                         goto invalid;
 607                         }
 608                 } else {
 609                         /*
 610                          * LHS
 611                          * - empty is allowed; it means delete.
 612                          * - when wildcarded, it must be a valid looking ref.
 613                          * - otherwise, it must be an extended SHA-1, but
 614                          *   there is no existing way to validate this.
 615                          */
 616                         if (!*rs[i].src)
 617                                 ; /* empty is ok */
 618                         else if (is_glob) {
 619                                 st = verify_refname(rs[i].src, is_glob);
 620                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 621                                         goto invalid;
 622                         }
 623                         else
 624                                 ; /* anything goes, for now */
 625                         /*
 626                          * RHS
 627                          * - missing is allowed, but LHS then must be a
 628                          *   valid looking ref.
 629                          * - empty is not allowed.
 630                          * - otherwise it must be a valid looking ref.
 631                          */
 632                         if (!rs[i].dst) {
 633                                 st = verify_refname(rs[i].src, is_glob);
 634                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 635                                         goto invalid;
 636                         } else if (!*rs[i].dst) {
 637                                 goto invalid;
 638                         } else {
 639                                 st = verify_refname(rs[i].dst, is_glob);
 640                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 641                                         goto invalid;
 642                         }
 643                 }
 644         }
 645         return rs;
 646
 647  invalid:
 648         if (verify) {
 649                 /*
 650                  * nr_refspec must be greater than zero and i must be valid
 651                  * since it is only possible to reach this point from within
 652                  * the for loop above.
 653                  */
 654                 free_refspecs(rs, i+1);
 655                 return NULL;
 656         }
 657         die("Invalid refspec '%s'", refspec[i]);
 658 }
 659
 660 int valid_fetch_refspec(const char *fetch_refspec_str)
 661 {
 662         struct refspec *refspec;
 663
 664         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
 665         free_refspecs(refspec, 1);
 666         return !!refspec;
 667 }
 668
 669 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 670 {
 671         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 672 }
 673
 674 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 675 {
 676         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 677 }
 678
 679 void free_refspec(int nr_refspec, struct refspec *refspec)
 680 {
 681         int i;
 682         for (i = 0; i < nr_refspec; i++) {
 683                 free(refspec[i].src);
 684                 free(refspec[i].dst);
 685         }
 686         free(refspec);
 687 }
 688
 689 static int valid_remote_nick(const char *name)
 690 {
 691         if (!name[0] || is_dot_or_dotdot(name))
 692                 return 0;
 693         return !strchr(name, '/'); /* no slash */
 694 }
 695
 696 struct remote *remote_get(const char *name)
 697 {
 698         struct remote *ret;
 699         int name_given = 0;
 700
 701         read_config();
 702         if (name)
 703                 name_given = 1;
 704         else {
 705                 name = default_remote_name;
 706                 name_given = explicit_default_remote_name;
 707         }
 708
 709         ret = make_remote(name, 0);
 710         if (valid_remote_nick(name)) {
 711                 if (!valid_remote(ret))
 712                         read_remotes_file(ret);
 713                 if (!valid_remote(ret))
 714                         read_branches_file(ret);
 715         }
 716         if (name_given && !valid_remote(ret))
 717                 add_url_alias(ret, name);
 718         if (!valid_remote(ret))
 719                 return NULL;
 720         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 721         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 722         return ret;
 723 }
 724
 725 int remote_is_configured(const char *name)
 726 {
 727         int i;
 728         read_config();
 729
 730         for (i = 0; i < remotes_nr; i++)
 731                 if (!strcmp(name, remotes[i]->name))
 732                         return 1;
 733         return 0;
 734 }
 735
 736 int for_each_remote(each_remote_fn fn, void *priv)
 737 {
 738         int i, result = 0;
 739         read_config();
 740         for (i = 0; i < remotes_nr && !result; i++) {
 741                 struct remote *r = remotes[i];
 742                 if (!r)
 743                         continue;
 744                 if (!r->fetch)
 745                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 746                                                        r->fetch_refspec);
 747                 if (!r->push)
 748                         r->push = parse_push_refspec(r->push_refspec_nr,
 749                                                      r->push_refspec);
 750                 result = fn(r, priv);
 751         }
 752         return result;
 753 }
 754
 755 void ref_remove_duplicates(struct ref *ref_map)
 756 {
 757         struct string_list refs = STRING_LIST_INIT_NODUP;
 758         struct string_list_item *item = NULL;
 759         struct ref *prev = NULL, *next = NULL;
 760         for (; ref_map; prev = ref_map, ref_map = next) {
 761                 next = ref_map->next;
 762                 if (!ref_map->peer_ref)
 763                         continue;
 764
 765                 item = string_list_lookup(&refs, ref_map->peer_ref->name);
 766                 if (item) {
 767                         if (strcmp(((struct ref *)item->util)->name,
 768                                    ref_map->name))
 769                                 die("%s tracks both %s and %s",
 770                                     ref_map->peer_ref->name,
 771                                     ((struct ref *)item->util)->name,
 772                                     ref_map->name);
 773                         prev->next = ref_map->next;
 774                         free(ref_map->peer_ref);
 775                         free(ref_map);
 776                         ref_map = prev; /* skip this; we freed it */
 777                         continue;
 778                 }
 779
 780                 item = string_list_insert(&refs, ref_map->peer_ref->name);
 781                 item->util = ref_map;
 782         }
 783         string_list_clear(&refs, 0);
 784 }
 785
 786 int remote_has_url(struct remote *remote, const char *url)
 787 {
 788         int i;
 789         for (i = 0; i < remote->url_nr; i++) {
 790                 if (!strcmp(remote->url[i], url))
 791                         return 1;
 792         }
 793         return 0;
 794 }
 795
 796 static int match_name_with_pattern(const char *key, const char *name,
 797                                    const char *value, char **result)
 798 {
 799         const char *kstar = strchr(key, '*');
 800         size_t klen;
 801         size_t ksuffixlen;
 802         size_t namelen;
 803         int ret;
 804         if (!kstar)
 805                 die("Key '%s' of pattern had no '*'", key);
 806         klen = kstar - key;
 807         ksuffixlen = strlen(kstar + 1);
 808         namelen = strlen(name);
 809         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 810                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 811         if (ret && value) {
 812                 const char *vstar = strchr(value, '*');
 813                 size_t vlen;
 814                 size_t vsuffixlen;
 815                 if (!vstar)
 816                         die("Value '%s' of pattern has no '*'", value);
 817                 vlen = vstar - value;
 818                 vsuffixlen = strlen(vstar + 1);
 819                 *result = xmalloc(vlen + vsuffixlen +
 820                                   strlen(name) -
 821                                   klen - ksuffixlen + 1);
 822                 strncpy(*result, value, vlen);
 823                 strncpy(*result + vlen,
 824                         name + klen, namelen - klen - ksuffixlen);
 825                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
 826                        vstar + 1);
 827         }
 828         return ret;
 829 }
 830
 831 static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
 832 {
 833         int i;
 834         int find_src = !query->src;
 835
 836         if (find_src && !query->dst)
 837                 return error("query_refspecs: need either src or dst");
 838
 839         for (i = 0; i < ref_count; i++) {
 840                 struct refspec *refspec = &refs[i];
 841                 const char *key = find_src ? refspec->dst : refspec->src;
 842                 const char *value = find_src ? refspec->src : refspec->dst;
 843                 const char *needle = find_src ? query->dst : query->src;
 844                 char **result = find_src ? &query->src : &query->dst;
 845
 846                 if (!refspec->dst)
 847                         continue;
 848                 if (refspec->pattern) {
 849                         if (match_name_with_pattern(key, needle, value, result)) {
 850                                 query->force = refspec->force;
 851                                 return 0;
 852                         }
 853                 } else if (!strcmp(needle, key)) {
 854                         *result = xstrdup(value);
 855                         query->force = refspec->force;
 856                         return 0;
 857                 }
 858         }
 859         return -1;
 860 }
 861
 862 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 863                      const char *name)
 864 {
 865         struct refspec query;
 866
 867         memset(&query, 0, sizeof(struct refspec));
 868         query.src = (char *)name;
 869
 870         if (query_refspecs(refspecs, nr_refspec, &query))
 871                 return NULL;
 872
 873         return query.dst;
 874 }
 875
 876 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 877 {
 878         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
 879 }
 880
 881 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 882                 const char *name)
 883 {
 884         size_t len = strlen(name);
 885         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 886         memcpy(ref->name, prefix, prefixlen);
 887         memcpy(ref->name + prefixlen, name, len);
 888         return ref;
 889 }
 890
 891 struct ref *alloc_ref(const char *name)
 892 {
 893         return alloc_ref_with_prefix("", 0, name);
 894 }
 895
 896 struct ref *copy_ref(const struct ref *ref)
 897 {
 898         struct ref *cpy;
 899         size_t len;
 900         if (!ref)
 901                 return NULL;
 902         len = strlen(ref->name);
 903         cpy = xmalloc(sizeof(struct ref) + len + 1);
 904         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 905         cpy->next = NULL;
 906         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 907         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 908         cpy->peer_ref = copy_ref(ref->peer_ref);
 909         return cpy;
 910 }
 911
 912 struct ref *copy_ref_list(const struct ref *ref)
 913 {
 914         struct ref *ret = NULL;
 915         struct ref **tail = &ret;
 916         while (ref) {
 917                 *tail = copy_ref(ref);
 918                 ref = ref->next;
 919                 tail = &((*tail)->next);
 920         }
 921         return ret;
 922 }
 923
 924 static void free_ref(struct ref *ref)
 925 {
 926         if (!ref)
 927                 return;
 928         free_ref(ref->peer_ref);
 929         free(ref->remote_status);
 930         free(ref->symref);
 931         free(ref);
 932 }
 933
 934 void free_refs(struct ref *ref)
 935 {
 936         struct ref *next;
 937         while (ref) {
 938                 next = ref->next;
 939                 free_ref(ref);
 940                 ref = next;
 941         }
 942 }
 943
 944 static int count_refspec_match(const char *pattern,
 945                                struct ref *refs,
 946                                struct ref **matched_ref)
 947 {
 948         int patlen = strlen(pattern);
 949         struct ref *matched_weak = NULL;
 950         struct ref *matched = NULL;
 951         int weak_match = 0;
 952         int match = 0;
 953
 954         for (weak_match = match = 0; refs; refs = refs->next) {
 955                 char *name = refs->name;
 956                 int namelen = strlen(name);
 957
 958                 if (!refname_match(pattern, name, ref_rev_parse_rules))
 959                         continue;
 960
 961                 /* A match is "weak" if it is with refs outside
 962                  * heads or tags, and did not specify the pattern
 963                  * in full (e.g. "refs/remotes/origin/master") or at
 964                  * least from the toplevel (e.g. "remotes/origin/master");
 965                  * otherwise "git push $URL master" would result in
 966                  * ambiguity between remotes/origin/master and heads/master
 967                  * at the remote site.
 968                  */
 969                 if (namelen != patlen &&
 970                     patlen != namelen - 5 &&
 971                     prefixcmp(name, "refs/heads/") &&
 972                     prefixcmp(name, "refs/tags/")) {
 973                         /* We want to catch the case where only weak
 974                          * matches are found and there are multiple
 975                          * matches, and where more than one strong
 976                          * matches are found, as ambiguous.  One
 977                          * strong match with zero or more weak matches
 978                          * are acceptable as a unique match.
 979                          */
 980                         matched_weak = refs;
 981                         weak_match++;
 982                 }
 983                 else {
 984                         matched = refs;
 985                         match++;
 986                 }
 987         }
 988         if (!matched) {
 989                 *matched_ref = matched_weak;
 990                 return weak_match;
 991         }
 992         else {
 993                 *matched_ref = matched;
 994                 return match;
 995         }
 996 }
 997
 998 static void tail_link_ref(struct ref *ref, struct ref ***tail)
 999 {
1000         **tail = ref;
1001         while (ref->next)
1002                 ref = ref->next;
1003         *tail = &ref->next;
1004 }
1005
1006 static struct ref *try_explicit_object_name(const char *name)
1007 {
1008         unsigned char sha1[20];
1009         struct ref *ref;
1010
1011         if (!*name) {
1012                 ref = alloc_ref("(delete)");
1013                 hashclr(ref->new_sha1);
1014                 return ref;
1015         }
1016         if (get_sha1(name, sha1))
1017                 return NULL;
1018         ref = alloc_ref(name);
1019         hashcpy(ref->new_sha1, sha1);
1020         return ref;
1021 }
1022
1023 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1024 {
1025         struct ref *ret = alloc_ref(name);
1026         tail_link_ref(ret, tail);
1027         return ret;
1028 }
1029
1030 static char *guess_ref(const char *name, struct ref *peer)
1031 {
1032         struct strbuf buf = STRBUF_INIT;
1033         unsigned char sha1[20];
1034
1035         const char *r = resolve_ref(peer->name, sha1, 1, NULL);
1036         if (!r)
1037                 return NULL;
1038
1039         if (!prefixcmp(r, "refs/heads/"))
1040                 strbuf_addstr(&buf, "refs/heads/");
1041         else if (!prefixcmp(r, "refs/tags/"))
1042                 strbuf_addstr(&buf, "refs/tags/");
1043         else
1044                 return NULL;
1045
1046         strbuf_addstr(&buf, name);
1047         return strbuf_detach(&buf, NULL);
1048 }
1049
1050 static int match_explicit(struct ref *src, struct ref *dst,
1051                           struct ref ***dst_tail,
1052                           struct refspec *rs)
1053 {
1054         struct ref *matched_src, *matched_dst;
1055         int copy_src;
1056
1057         const char *dst_value = rs->dst;
1058         char *dst_guess;
1059
1060         if (rs->pattern || rs->matching)
1061                 return 0;
1062
1063         matched_src = matched_dst = NULL;
1064         switch (count_refspec_match(rs->src, src, &matched_src)) {
1065         case 1:
1066                 copy_src = 1;
1067                 break;
1068         case 0:
1069                 /* The source could be in the get_sha1() format
1070                  * not a reference name.  :refs/other is a
1071                  * way to delete 'other' ref at the remote end.
1072                  */
1073                 matched_src = try_explicit_object_name(rs->src);
1074                 if (!matched_src)
1075                         return error("src refspec %s does not match any.", rs->src);
1076                 copy_src = 0;
1077                 break;
1078         default:
1079                 return error("src refspec %s matches more than one.", rs->src);
1080         }
1081
1082         if (!dst_value) {
1083                 unsigned char sha1[20];
1084                 int flag;
1085
1086                 dst_value = resolve_ref(matched_src->name, sha1, 1, &flag);
1087                 if (!dst_value ||
1088                     ((flag & REF_ISSYMREF) &&
1089                      prefixcmp(dst_value, "refs/heads/")))
1090                         die("%s cannot be resolved to branch.",
1091                             matched_src->name);
1092         }
1093
1094         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1095         case 1:
1096                 break;
1097         case 0:
1098                 if (!memcmp(dst_value, "refs/", 5))
1099                         matched_dst = make_linked_ref(dst_value, dst_tail);
1100                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1101                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1102                 else
1103                         error("unable to push to unqualified destination: %s\n"
1104                               "The destination refspec neither matches an "
1105                               "existing ref on the remote nor\n"
1106                               "begins with refs/, and we are unable to "
1107                               "guess a prefix based on the source ref.",
1108                               dst_value);
1109                 break;
1110         default:
1111                 matched_dst = NULL;
1112                 error("dst refspec %s matches more than one.",
1113                       dst_value);
1114                 break;
1115         }
1116         if (!matched_dst)
1117                 return -1;
1118         if (matched_dst->peer_ref)
1119                 return error("dst ref %s receives from more than one src.",
1120                       matched_dst->name);
1121         else {
1122                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1123                 matched_dst->force = rs->force;
1124         }
1125         return 0;
1126 }
1127
1128 static int match_explicit_refs(struct ref *src, struct ref *dst,
1129                                struct ref ***dst_tail, struct refspec *rs,
1130                                int rs_nr)
1131 {
1132         int i, errs;
1133         for (i = errs = 0; i < rs_nr; i++)
1134                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1135         return errs;
1136 }
1137
1138 static const struct refspec *check_pattern_match(const struct refspec *rs,
1139                                                  int rs_nr,
1140                                                  const struct ref *src)
1141 {
1142         int i;
1143         int matching_refs = -1;
1144         for (i = 0; i < rs_nr; i++) {
1145                 if (rs[i].matching &&
1146                     (matching_refs == -1 || rs[i].force)) {
1147                         matching_refs = i;
1148                         continue;
1149                 }
1150
1151                 if (rs[i].pattern && match_name_with_pattern(rs[i].src, src->name,
1152                                                              NULL, NULL))
1153                         return rs + i;
1154         }
1155         if (matching_refs != -1)
1156                 return rs + matching_refs;
1157         else
1158                 return NULL;
1159 }
1160
1161 static struct ref **tail_ref(struct ref **head)
1162 {
1163         struct ref **tail = head;
1164         while (*tail)
1165                 tail = &((*tail)->next);
1166         return tail;
1167 }
1168
1169 /*
1170  * Note. This is used only by "push"; refspec matching rules for
1171  * push and fetch are subtly different, so do not try to reuse it
1172  * without thinking.
1173  */
1174 int match_refs(struct ref *src, struct ref **dst,
1175                int nr_refspec, const char **refspec, int flags)
1176 {
1177         struct refspec *rs;
1178         int send_all = flags & MATCH_REFS_ALL;
1179         int send_mirror = flags & MATCH_REFS_MIRROR;
1180         int errs;
1181         static const char *default_refspec[] = { ":", NULL };
1182         struct ref **dst_tail = tail_ref(dst);
1183
1184         if (!nr_refspec) {
1185                 nr_refspec = 1;
1186                 refspec = default_refspec;
1187         }
1188         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1189         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1190
1191         /* pick the remainder */
1192         for ( ; src; src = src->next) {
1193                 struct ref *dst_peer;
1194                 const struct refspec *pat = NULL;
1195                 char *dst_name;
1196                 if (src->peer_ref)
1197                         continue;
1198
1199                 pat = check_pattern_match(rs, nr_refspec, src);
1200                 if (!pat)
1201                         continue;
1202
1203                 if (pat->matching) {
1204                         /*
1205                          * "matching refs"; traditionally we pushed everything
1206                          * including refs outside refs/heads/ hierarchy, but
1207                          * that does not make much sense these days.
1208                          */
1209                         if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
1210                                 continue;
1211                         dst_name = xstrdup(src->name);
1212
1213                 } else {
1214                         const char *dst_side = pat->dst ? pat->dst : pat->src;
1215                         if (!match_name_with_pattern(pat->src, src->name,
1216                                                      dst_side, &dst_name))
1217                                 die("Didn't think it matches any more");
1218                 }
1219                 dst_peer = find_ref_by_name(*dst, dst_name);
1220                 if (dst_peer) {
1221                         if (dst_peer->peer_ref)
1222                                 /* We're already sending something to this ref. */
1223                                 goto free_name;
1224
1225                 } else {
1226                         if (pat->matching && !(send_all || send_mirror))
1227                                 /*
1228                                  * Remote doesn't have it, and we have no
1229                                  * explicit pattern, and we don't have
1230                                  * --all nor --mirror.
1231                                  */
1232                                 goto free_name;
1233
1234                         /* Create a new one and link it */
1235                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1236                         hashcpy(dst_peer->new_sha1, src->new_sha1);
1237                 }
1238                 dst_peer->peer_ref = copy_ref(src);
1239                 dst_peer->force = pat->force;
1240         free_name:
1241                 free(dst_name);
1242         }
1243         if (errs)
1244                 return -1;
1245         return 0;
1246 }
1247
1248 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1249         int force_update)
1250 {
1251         struct ref *ref;
1252
1253         for (ref = remote_refs; ref; ref = ref->next) {
1254                 if (ref->peer_ref)
1255                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1256                 else if (!send_mirror)
1257                         continue;
1258
1259                 ref->deletion = is_null_sha1(ref->new_sha1);
1260                 if (!ref->deletion &&
1261                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1262                         ref->status = REF_STATUS_UPTODATE;
1263                         continue;
1264                 }
1265
1266                 /* This part determines what can overwrite what.
1267                  * The rules are:
1268                  *
1269                  * (0) you can always use --force or +A:B notation to
1270                  *     selectively force individual ref pairs.
1271                  *
1272                  * (1) if the old thing does not exist, it is OK.
1273                  *
1274                  * (2) if you do not have the old thing, you are not allowed
1275                  *     to overwrite it; you would not know what you are losing
1276                  *     otherwise.
1277                  *
1278                  * (3) if both new and old are commit-ish, and new is a
1279                  *     descendant of old, it is OK.
1280                  *
1281                  * (4) regardless of all of the above, removing :B is
1282                  *     always allowed.
1283                  */
1284
1285                 ref->nonfastforward =
1286                         !ref->deletion &&
1287                         !is_null_sha1(ref->old_sha1) &&
1288                         (!has_sha1_file(ref->old_sha1)
1289                           || !ref_newer(ref->new_sha1, ref->old_sha1));
1290
1291                 if (ref->nonfastforward && !ref->force && !force_update) {
1292                         ref->status = REF_STATUS_REJECT_NONFASTFORWARD;
1293                         continue;
1294                 }
1295         }
1296 }
1297
1298 struct branch *branch_get(const char *name)
1299 {
1300         struct branch *ret;
1301
1302         read_config();
1303         if (!name || !*name || !strcmp(name, "HEAD"))
1304                 ret = current_branch;
1305         else
1306                 ret = make_branch(name, 0);
1307         if (ret && ret->remote_name) {
1308                 ret->remote = remote_get(ret->remote_name);
1309                 if (ret->merge_nr) {
1310                         int i;
1311                         ret->merge = xcalloc(sizeof(*ret->merge),
1312                                              ret->merge_nr);
1313                         for (i = 0; i < ret->merge_nr; i++) {
1314                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1315                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1316                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1317                                     && !strcmp(ret->remote_name, "."))
1318                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1319                         }
1320                 }
1321         }
1322         return ret;
1323 }
1324
1325 int branch_has_merge_config(struct branch *branch)
1326 {
1327         return branch && !!branch->merge;
1328 }
1329
1330 int branch_merge_matches(struct branch *branch,
1331                                  int i,
1332                                  const char *refname)
1333 {
1334         if (!branch || i < 0 || i >= branch->merge_nr)
1335                 return 0;
1336         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1337 }
1338
1339 static struct ref *get_expanded_map(const struct ref *remote_refs,
1340                                     const struct refspec *refspec)
1341 {
1342         const struct ref *ref;
1343         struct ref *ret = NULL;
1344         struct ref **tail = &ret;
1345
1346         char *expn_name;
1347
1348         for (ref = remote_refs; ref; ref = ref->next) {
1349                 if (strchr(ref->name, '^'))
1350                         continue; /* a dereference item */
1351                 if (match_name_with_pattern(refspec->src, ref->name,
1352                                             refspec->dst, &expn_name)) {
1353                         struct ref *cpy = copy_ref(ref);
1354
1355                         cpy->peer_ref = alloc_ref(expn_name);
1356                         free(expn_name);
1357                         if (refspec->force)
1358                                 cpy->peer_ref->force = 1;
1359                         *tail = cpy;
1360                         tail = &cpy->next;
1361                 }
1362         }
1363
1364         return ret;
1365 }
1366
1367 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1368 {
1369         const struct ref *ref;
1370         for (ref = refs; ref; ref = ref->next) {
1371                 if (refname_match(name, ref->name, ref_fetch_rules))
1372                         return ref;
1373         }
1374         return NULL;
1375 }
1376
1377 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1378 {
1379         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1380
1381         if (!ref)
1382                 return NULL;
1383
1384         return copy_ref(ref);
1385 }
1386
1387 static struct ref *get_local_ref(const char *name)
1388 {
1389         if (!name || name[0] == '\0')
1390                 return NULL;
1391
1392         if (!prefixcmp(name, "refs/"))
1393                 return alloc_ref(name);
1394
1395         if (!prefixcmp(name, "heads/") ||
1396             !prefixcmp(name, "tags/") ||
1397             !prefixcmp(name, "remotes/"))
1398                 return alloc_ref_with_prefix("refs/", 5, name);
1399
1400         return alloc_ref_with_prefix("refs/heads/", 11, name);
1401 }
1402
1403 int get_fetch_map(const struct ref *remote_refs,
1404                   const struct refspec *refspec,
1405                   struct ref ***tail,
1406                   int missing_ok)
1407 {
1408         struct ref *ref_map, **rmp;
1409
1410         if (refspec->pattern) {
1411                 ref_map = get_expanded_map(remote_refs, refspec);
1412         } else {
1413                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1414
1415                 ref_map = get_remote_ref(remote_refs, name);
1416                 if (!missing_ok && !ref_map)
1417                         die("Couldn't find remote ref %s", name);
1418                 if (ref_map) {
1419                         ref_map->peer_ref = get_local_ref(refspec->dst);
1420                         if (ref_map->peer_ref && refspec->force)
1421                                 ref_map->peer_ref->force = 1;
1422                 }
1423         }
1424
1425         for (rmp = &ref_map; *rmp; ) {
1426                 if ((*rmp)->peer_ref) {
1427                         int st = check_ref_format((*rmp)->peer_ref->name + 5);
1428                         if (st && st != CHECK_REF_FORMAT_ONELEVEL) {
1429                                 struct ref *ignore = *rmp;
1430                                 error("* Ignoring funny ref '%s' locally",
1431                                       (*rmp)->peer_ref->name);
1432                                 *rmp = (*rmp)->next;
1433                                 free(ignore->peer_ref);
1434                                 free(ignore);
1435                                 continue;
1436                         }
1437                 }
1438                 rmp = &((*rmp)->next);
1439         }
1440
1441         if (ref_map)
1442                 tail_link_ref(ref_map, tail);
1443
1444         return 0;
1445 }
1446
1447 int resolve_remote_symref(struct ref *ref, struct ref *list)
1448 {
1449         if (!ref->symref)
1450                 return 0;
1451         for (; list; list = list->next)
1452                 if (!strcmp(ref->symref, list->name)) {
1453                         hashcpy(ref->old_sha1, list->old_sha1);
1454                         return 0;
1455                 }
1456         return 1;
1457 }
1458
1459 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1460 {
1461         while (list) {
1462                 struct commit_list *temp = list;
1463                 temp->item->object.flags &= ~mark;
1464                 list = temp->next;
1465                 free(temp);
1466         }
1467 }
1468
1469 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1470 {
1471         struct object *o;
1472         struct commit *old, *new;
1473         struct commit_list *list, *used;
1474         int found = 0;
1475
1476         /* Both new and old must be commit-ish and new is descendant of
1477          * old.  Otherwise we require --force.
1478          */
1479         o = deref_tag(parse_object(old_sha1), NULL, 0);
1480         if (!o || o->type != OBJ_COMMIT)
1481                 return 0;
1482         old = (struct commit *) o;
1483
1484         o = deref_tag(parse_object(new_sha1), NULL, 0);
1485         if (!o || o->type != OBJ_COMMIT)
1486                 return 0;
1487         new = (struct commit *) o;
1488
1489         if (parse_commit(new) < 0)
1490                 return 0;
1491
1492         used = list = NULL;
1493         commit_list_insert(new, &list);
1494         while (list) {
1495                 new = pop_most_recent_commit(&list, TMP_MARK);
1496                 commit_list_insert(new, &used);
1497                 if (new == old) {
1498                         found = 1;
1499                         break;
1500                 }
1501         }
1502         unmark_and_free(list, TMP_MARK);
1503         unmark_and_free(used, TMP_MARK);
1504         return found;
1505 }
1506
1507 /*
1508  * Return true if there is anything to report, otherwise false.
1509  */
1510 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1511 {
1512         unsigned char sha1[20];
1513         struct commit *ours, *theirs;
1514         char symmetric[84];
1515         struct rev_info revs;
1516         const char *rev_argv[10], *base;
1517         int rev_argc;
1518
1519         /*
1520          * Nothing to report unless we are marked to build on top of
1521          * somebody else.
1522          */
1523         if (!branch ||
1524             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1525                 return 0;
1526
1527         /*
1528          * If what we used to build on no longer exists, there is
1529          * nothing to report.
1530          */
1531         base = branch->merge[0]->dst;
1532         if (!resolve_ref(base, sha1, 1, NULL))
1533                 return 0;
1534         theirs = lookup_commit_reference(sha1);
1535         if (!theirs)
1536                 return 0;
1537
1538         if (!resolve_ref(branch->refname, sha1, 1, NULL))
1539                 return 0;
1540         ours = lookup_commit_reference(sha1);
1541         if (!ours)
1542                 return 0;
1543
1544         /* are we the same? */
1545         if (theirs == ours)
1546                 return 0;
1547
1548         /* Run "rev-list --left-right ours...theirs" internally... */
1549         rev_argc = 0;
1550         rev_argv[rev_argc++] = NULL;
1551         rev_argv[rev_argc++] = "--left-right";
1552         rev_argv[rev_argc++] = symmetric;
1553         rev_argv[rev_argc++] = "--";
1554         rev_argv[rev_argc] = NULL;
1555
1556         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1557         strcpy(symmetric + 40, "...");
1558         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1559
1560         init_revisions(&revs, NULL);
1561         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1562         prepare_revision_walk(&revs);
1563
1564         /* ... and count the commits on each side. */
1565         *num_ours = 0;
1566         *num_theirs = 0;
1567         while (1) {
1568                 struct commit *c = get_revision(&revs);
1569                 if (!c)
1570                         break;
1571                 if (c->object.flags & SYMMETRIC_LEFT)
1572                         (*num_ours)++;
1573                 else
1574                         (*num_theirs)++;
1575         }
1576
1577         /* clear object flags smudged by the above traversal */
1578         clear_commit_marks(ours, ALL_REV_FLAGS);
1579         clear_commit_marks(theirs, ALL_REV_FLAGS);
1580         return 1;
1581 }
1582
1583 /*
1584  * Return true when there is anything to report, otherwise false.
1585  */
1586 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1587 {
1588         int num_ours, num_theirs;
1589         const char *base;
1590
1591         if (!stat_tracking_info(branch, &num_ours, &num_theirs))
1592                 return 0;
1593
1594         base = branch->merge[0]->dst;
1595         base = shorten_unambiguous_ref(base, 0);
1596         if (!num_theirs)
1597                 strbuf_addf(sb, "Your branch is ahead of '%s' "
1598                             "by %d commit%s.\n",
1599                             base, num_ours, (num_ours == 1) ? "" : "s");
1600         else if (!num_ours)
1601                 strbuf_addf(sb, "Your branch is behind '%s' "
1602                             "by %d commit%s, "
1603                             "and can be fast-forwarded.\n",
1604                             base, num_theirs, (num_theirs == 1) ? "" : "s");
1605         else
1606                 strbuf_addf(sb, "Your branch and '%s' have diverged,\n"
1607                             "and have %d and %d different commit(s) each, "
1608                             "respectively.\n",
1609                             base, num_ours, num_theirs);
1610         return 1;
1611 }
1612
1613 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1614 {
1615         struct ref ***local_tail = cb_data;
1616         struct ref *ref;
1617         int len;
1618
1619         /* we already know it starts with refs/ to get here */
1620         if (check_ref_format(refname + 5))
1621                 return 0;
1622
1623         len = strlen(refname) + 1;
1624         ref = xcalloc(1, sizeof(*ref) + len);
1625         hashcpy(ref->new_sha1, sha1);
1626         memcpy(ref->name, refname, len);
1627         **local_tail = ref;
1628         *local_tail = &ref->next;
1629         return 0;
1630 }
1631
1632 struct ref *get_local_heads(void)
1633 {
1634         struct ref *local_refs = NULL, **local_tail = &local_refs;
1635         for_each_ref(one_local_ref, &local_tail);
1636         return local_refs;
1637 }
1638
1639 struct ref *guess_remote_head(const struct ref *head,
1640                               const struct ref *refs,
1641                               int all)
1642 {
1643         const struct ref *r;
1644         struct ref *list = NULL;
1645         struct ref **tail = &list;
1646
1647         if (!head)
1648                 return NULL;
1649
1650         /*
1651          * Some transports support directly peeking at
1652          * where HEAD points; if that is the case, then
1653          * we don't have to guess.
1654          */
1655         if (head->symref)
1656                 return copy_ref(find_ref_by_name(refs, head->symref));
1657
1658         /* If refs/heads/master could be right, it is. */
1659         if (!all) {
1660                 r = find_ref_by_name(refs, "refs/heads/master");
1661                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1662                         return copy_ref(r);
1663         }
1664
1665         /* Look for another ref that points there */
1666         for (r = refs; r; r = r->next) {
1667                 if (r != head &&
1668                     !prefixcmp(r->name, "refs/heads/") &&
1669                     !hashcmp(r->old_sha1, head->old_sha1)) {
1670                         *tail = copy_ref(r);
1671                         tail = &((*tail)->next);
1672                         if (!all)
1673                                 break;
1674                 }
1675         }
1676
1677         return list;
1678 }
1679
1680 struct stale_heads_info {
1681         struct string_list *ref_names;
1682         struct ref **stale_refs_tail;
1683         struct refspec *refs;
1684         int ref_count;
1685 };
1686
1687 static int get_stale_heads_cb(const char *refname,
1688         const unsigned char *sha1, int flags, void *cb_data)
1689 {
1690         struct stale_heads_info *info = cb_data;
1691         struct refspec query;
1692         memset(&query, 0, sizeof(struct refspec));
1693         query.dst = (char *)refname;
1694
1695         if (query_refspecs(info->refs, info->ref_count, &query))
1696                 return 0; /* No matches */
1697
1698         /*
1699          * If we did find a suitable refspec and it's not a symref and
1700          * it's not in the list of refs that currently exist in that
1701          * remote we consider it to be stale.
1702          */
1703         if (!((flags & REF_ISSYMREF) ||
1704               string_list_has_string(info->ref_names, query.src))) {
1705                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
1706                 hashcpy(ref->new_sha1, sha1);
1707         }
1708
1709         free(query.src);
1710         return 0;
1711 }
1712
1713 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
1714 {
1715         struct ref *ref, *stale_refs = NULL;
1716         struct string_list ref_names = STRING_LIST_INIT_NODUP;
1717         struct stale_heads_info info;
1718         info.ref_names = &ref_names;
1719         info.stale_refs_tail = &stale_refs;
1720         info.refs = refs;
1721         info.ref_count = ref_count;
1722         for (ref = fetch_map; ref; ref = ref->next)
1723                 string_list_append(&ref_names, ref->name);
1724         sort_string_list(&ref_names);
1725         for_each_ref(get_stale_heads_cb, &info);
1726         string_list_clear(&ref_names, 0);
1727         return stale_refs;
1728 }