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