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