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 for_each_remote(each_remote_fn fn, void *priv)
 671 {
 672         int i, result = 0;
 673         read_config();
 674         for (i = 0; i < remotes_nr && !result; i++) {
 675                 struct remote *r = remotes[i];
 676                 if (!r)
 677                         continue;
 678                 if (!r->fetch)
 679                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 680                                                        r->fetch_refspec);
 681                 if (!r->push)
 682                         r->push = parse_push_refspec(r->push_refspec_nr,
 683                                                      r->push_refspec);
 684                 result = fn(r, priv);
 685         }
 686         return result;
 687 }
 688
 689 void ref_remove_duplicates(struct ref *ref_map)
 690 {
 691         struct ref **posn;
 692         struct ref *next;
 693         for (; ref_map; ref_map = ref_map->next) {
 694                 if (!ref_map->peer_ref)
 695                         continue;
 696                 posn = &ref_map->next;
 697                 while (*posn) {
 698                         if ((*posn)->peer_ref &&
 699                             !strcmp((*posn)->peer_ref->name,
 700                                     ref_map->peer_ref->name)) {
 701                                 if (strcmp((*posn)->name, ref_map->name))
 702                                         die("%s tracks both %s and %s",
 703                                             ref_map->peer_ref->name,
 704                                             (*posn)->name, ref_map->name);
 705                                 next = (*posn)->next;
 706                                 free((*posn)->peer_ref);
 707                                 free(*posn);
 708                                 *posn = next;
 709                         } else {
 710                                 posn = &(*posn)->next;
 711                         }
 712                 }
 713         }
 714 }
 715
 716 int remote_has_url(struct remote *remote, const char *url)
 717 {
 718         int i;
 719         for (i = 0; i < remote->url_nr; i++) {
 720                 if (!strcmp(remote->url[i], url))
 721                         return 1;
 722         }
 723         return 0;
 724 }
 725
 726 static int match_name_with_pattern(const char *key, const char *name,
 727                                    const char *value, char **result)
 728 {
 729         const char *kstar = strchr(key, '*');
 730         size_t klen;
 731         size_t ksuffixlen;
 732         size_t namelen;
 733         int ret;
 734         if (!kstar)
 735                 die("Key '%s' of pattern had no '*'", key);
 736         klen = kstar - key;
 737         ksuffixlen = strlen(kstar + 1);
 738         namelen = strlen(name);
 739         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 740                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 741         if (ret && value) {
 742                 const char *vstar = strchr(value, '*');
 743                 size_t vlen;
 744                 size_t vsuffixlen;
 745                 if (!vstar)
 746                         die("Value '%s' of pattern has no '*'", value);
 747                 vlen = vstar - value;
 748                 vsuffixlen = strlen(vstar + 1);
 749                 *result = xmalloc(vlen + vsuffixlen +
 750                                   strlen(name) -
 751                                   klen - ksuffixlen + 1);
 752                 strncpy(*result, value, vlen);
 753                 strncpy(*result + vlen,
 754                         name + klen, namelen - klen - ksuffixlen);
 755                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
 756                        vstar + 1);
 757         }
 758         return ret;
 759 }
 760
 761 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 762 {
 763         int find_src = refspec->src == NULL;
 764         char *needle, **result;
 765         int i;
 766
 767         if (find_src) {
 768                 if (!refspec->dst)
 769                         return error("find_tracking: need either src or dst");
 770                 needle = refspec->dst;
 771                 result = &refspec->src;
 772         } else {
 773                 needle = refspec->src;
 774                 result = &refspec->dst;
 775         }
 776
 777         for (i = 0; i < remote->fetch_refspec_nr; i++) {
 778                 struct refspec *fetch = &remote->fetch[i];
 779                 const char *key = find_src ? fetch->dst : fetch->src;
 780                 const char *value = find_src ? fetch->src : fetch->dst;
 781                 if (!fetch->dst)
 782                         continue;
 783                 if (fetch->pattern) {
 784                         if (match_name_with_pattern(key, needle, value, result)) {
 785                                 refspec->force = fetch->force;
 786                                 return 0;
 787                         }
 788                 } else if (!strcmp(needle, key)) {
 789                         *result = xstrdup(value);
 790                         refspec->force = fetch->force;
 791                         return 0;
 792                 }
 793         }
 794         return -1;
 795 }
 796
 797 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 798                 const char *name)
 799 {
 800         size_t len = strlen(name);
 801         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 802         memcpy(ref->name, prefix, prefixlen);
 803         memcpy(ref->name + prefixlen, name, len);
 804         return ref;
 805 }
 806
 807 struct ref *alloc_ref(const char *name)
 808 {
 809         return alloc_ref_with_prefix("", 0, name);
 810 }
 811
 812 static struct ref *copy_ref(const struct ref *ref)
 813 {
 814         struct ref *cpy;
 815         size_t len;
 816         if (!ref)
 817                 return NULL;
 818         len = strlen(ref->name);
 819         cpy = xmalloc(sizeof(struct ref) + len + 1);
 820         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 821         cpy->next = NULL;
 822         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 823         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 824         cpy->peer_ref = copy_ref(ref->peer_ref);
 825         return cpy;
 826 }
 827
 828 struct ref *copy_ref_list(const struct ref *ref)
 829 {
 830         struct ref *ret = NULL;
 831         struct ref **tail = &ret;
 832         while (ref) {
 833                 *tail = copy_ref(ref);
 834                 ref = ref->next;
 835                 tail = &((*tail)->next);
 836         }
 837         return ret;
 838 }
 839
 840 static void free_ref(struct ref *ref)
 841 {
 842         if (!ref)
 843                 return;
 844         free_ref(ref->peer_ref);
 845         free(ref->remote_status);
 846         free(ref->symref);
 847         free(ref);
 848 }
 849
 850 void free_refs(struct ref *ref)
 851 {
 852         struct ref *next;
 853         while (ref) {
 854                 next = ref->next;
 855                 free_ref(ref);
 856                 ref = next;
 857         }
 858 }
 859
 860 static int count_refspec_match(const char *pattern,
 861                                struct ref *refs,
 862                                struct ref **matched_ref)
 863 {
 864         int patlen = strlen(pattern);
 865         struct ref *matched_weak = NULL;
 866         struct ref *matched = NULL;
 867         int weak_match = 0;
 868         int match = 0;
 869
 870         for (weak_match = match = 0; refs; refs = refs->next) {
 871                 char *name = refs->name;
 872                 int namelen = strlen(name);
 873
 874                 if (!refname_match(pattern, name, ref_rev_parse_rules))
 875                         continue;
 876
 877                 /* A match is "weak" if it is with refs outside
 878                  * heads or tags, and did not specify the pattern
 879                  * in full (e.g. "refs/remotes/origin/master") or at
 880                  * least from the toplevel (e.g. "remotes/origin/master");
 881                  * otherwise "git push $URL master" would result in
 882                  * ambiguity between remotes/origin/master and heads/master
 883                  * at the remote site.
 884                  */
 885                 if (namelen != patlen &&
 886                     patlen != namelen - 5 &&
 887                     prefixcmp(name, "refs/heads/") &&
 888                     prefixcmp(name, "refs/tags/")) {
 889                         /* We want to catch the case where only weak
 890                          * matches are found and there are multiple
 891                          * matches, and where more than one strong
 892                          * matches are found, as ambiguous.  One
 893                          * strong match with zero or more weak matches
 894                          * are acceptable as a unique match.
 895                          */
 896                         matched_weak = refs;
 897                         weak_match++;
 898                 }
 899                 else {
 900                         matched = refs;
 901                         match++;
 902                 }
 903         }
 904         if (!matched) {
 905                 *matched_ref = matched_weak;
 906                 return weak_match;
 907         }
 908         else {
 909                 *matched_ref = matched;
 910                 return match;
 911         }
 912 }
 913
 914 static void tail_link_ref(struct ref *ref, struct ref ***tail)
 915 {
 916         **tail = ref;
 917         while (ref->next)
 918                 ref = ref->next;
 919         *tail = &ref->next;
 920 }
 921
 922 static struct ref *try_explicit_object_name(const char *name)
 923 {
 924         unsigned char sha1[20];
 925         struct ref *ref;
 926
 927         if (!*name) {
 928                 ref = alloc_ref("(delete)");
 929                 hashclr(ref->new_sha1);
 930                 return ref;
 931         }
 932         if (get_sha1(name, sha1))
 933                 return NULL;
 934         ref = alloc_ref(name);
 935         hashcpy(ref->new_sha1, sha1);
 936         return ref;
 937 }
 938
 939 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
 940 {
 941         struct ref *ret = alloc_ref(name);
 942         tail_link_ref(ret, tail);
 943         return ret;
 944 }
 945
 946 static char *guess_ref(const char *name, struct ref *peer)
 947 {
 948         struct strbuf buf = STRBUF_INIT;
 949         unsigned char sha1[20];
 950
 951         const char *r = resolve_ref(peer->name, sha1, 1, NULL);
 952         if (!r)
 953                 return NULL;
 954
 955         if (!prefixcmp(r, "refs/heads/"))
 956                 strbuf_addstr(&buf, "refs/heads/");
 957         else if (!prefixcmp(r, "refs/tags/"))
 958                 strbuf_addstr(&buf, "refs/tags/");
 959         else
 960                 return NULL;
 961
 962         strbuf_addstr(&buf, name);
 963         return strbuf_detach(&buf, NULL);
 964 }
 965
 966 static int match_explicit(struct ref *src, struct ref *dst,
 967                           struct ref ***dst_tail,
 968                           struct refspec *rs)
 969 {
 970         struct ref *matched_src, *matched_dst;
 971         int copy_src;
 972
 973         const char *dst_value = rs->dst;
 974         char *dst_guess;
 975
 976         if (rs->pattern || rs->matching)
 977                 return 0;
 978
 979         matched_src = matched_dst = NULL;
 980         switch (count_refspec_match(rs->src, src, &matched_src)) {
 981         case 1:
 982                 copy_src = 1;
 983                 break;
 984         case 0:
 985                 /* The source could be in the get_sha1() format
 986                  * not a reference name.  :refs/other is a
 987                  * way to delete 'other' ref at the remote end.
 988                  */
 989                 matched_src = try_explicit_object_name(rs->src);
 990                 if (!matched_src)
 991                         return error("src refspec %s does not match any.", rs->src);
 992                 copy_src = 0;
 993                 break;
 994         default:
 995                 return error("src refspec %s matches more than one.", rs->src);
 996         }
 997
 998         if (!dst_value) {
 999                 unsigned char sha1[20];
1000                 int flag;
1001
1002                 dst_value = resolve_ref(matched_src->name, sha1, 1, &flag);
1003                 if (!dst_value ||
1004                     ((flag & REF_ISSYMREF) &&
1005                      prefixcmp(dst_value, "refs/heads/")))
1006                         die("%s cannot be resolved to branch.",
1007                             matched_src->name);
1008         }
1009
1010         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1011         case 1:
1012                 break;
1013         case 0:
1014                 if (!memcmp(dst_value, "refs/", 5))
1015                         matched_dst = make_linked_ref(dst_value, dst_tail);
1016                 else if((dst_guess = guess_ref(dst_value, matched_src)))
1017                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1018                 else
1019                         error("unable to push to unqualified destination: %s\n"
1020                               "The destination refspec neither matches an "
1021                               "existing ref on the remote nor\n"
1022                               "begins with refs/, and we are unable to "
1023                               "guess a prefix based on the source ref.",
1024                               dst_value);
1025                 break;
1026         default:
1027                 matched_dst = NULL;
1028                 error("dst refspec %s matches more than one.",
1029                       dst_value);
1030                 break;
1031         }
1032         if (!matched_dst)
1033                 return -1;
1034         if (matched_dst->peer_ref)
1035                 return error("dst ref %s receives from more than one src.",
1036                       matched_dst->name);
1037         else {
1038                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1039                 matched_dst->force = rs->force;
1040         }
1041         return 0;
1042 }
1043
1044 static int match_explicit_refs(struct ref *src, struct ref *dst,
1045                                struct ref ***dst_tail, struct refspec *rs,
1046                                int rs_nr)
1047 {
1048         int i, errs;
1049         for (i = errs = 0; i < rs_nr; i++)
1050                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1051         return errs;
1052 }
1053
1054 static const struct refspec *check_pattern_match(const struct refspec *rs,
1055                                                  int rs_nr,
1056                                                  const struct ref *src)
1057 {
1058         int i;
1059         int matching_refs = -1;
1060         for (i = 0; i < rs_nr; i++) {
1061                 if (rs[i].matching &&
1062                     (matching_refs == -1 || rs[i].force)) {
1063                         matching_refs = i;
1064                         continue;
1065                 }
1066
1067                 if (rs[i].pattern && match_name_with_pattern(rs[i].src, src->name,
1068                                                              NULL, NULL))
1069                         return rs + i;
1070         }
1071         if (matching_refs != -1)
1072                 return rs + matching_refs;
1073         else
1074                 return NULL;
1075 }
1076
1077 /*
1078  * Note. This is used only by "push"; refspec matching rules for
1079  * push and fetch are subtly different, so do not try to reuse it
1080  * without thinking.
1081  */
1082 int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
1083                int nr_refspec, const char **refspec, int flags)
1084 {
1085         struct refspec *rs;
1086         int send_all = flags & MATCH_REFS_ALL;
1087         int send_mirror = flags & MATCH_REFS_MIRROR;
1088         int errs;
1089         static const char *default_refspec[] = { ":", 0 };
1090
1091         if (!nr_refspec) {
1092                 nr_refspec = 1;
1093                 refspec = default_refspec;
1094         }
1095         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1096         errs = match_explicit_refs(src, dst, dst_tail, rs, nr_refspec);
1097
1098         /* pick the remainder */
1099         for ( ; src; src = src->next) {
1100                 struct ref *dst_peer;
1101                 const struct refspec *pat = NULL;
1102                 char *dst_name;
1103                 if (src->peer_ref)
1104                         continue;
1105
1106                 pat = check_pattern_match(rs, nr_refspec, src);
1107                 if (!pat)
1108                         continue;
1109
1110                 if (pat->matching) {
1111                         /*
1112                          * "matching refs"; traditionally we pushed everything
1113                          * including refs outside refs/heads/ hierarchy, but
1114                          * that does not make much sense these days.
1115                          */
1116                         if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
1117                                 continue;
1118                         dst_name = xstrdup(src->name);
1119
1120                 } else {
1121                         const char *dst_side = pat->dst ? pat->dst : pat->src;
1122                         if (!match_name_with_pattern(pat->src, src->name,
1123                                                      dst_side, &dst_name))
1124                                 die("Didn't think it matches any more");
1125                 }
1126                 dst_peer = find_ref_by_name(dst, dst_name);
1127                 if (dst_peer) {
1128                         if (dst_peer->peer_ref)
1129                                 /* We're already sending something to this ref. */
1130                                 goto free_name;
1131
1132                 } else {
1133                         if (pat->matching && !(send_all || send_mirror))
1134                                 /*
1135                                  * Remote doesn't have it, and we have no
1136                                  * explicit pattern, and we don't have
1137                                  * --all nor --mirror.
1138                                  */
1139                                 goto free_name;
1140
1141                         /* Create a new one and link it */
1142                         dst_peer = make_linked_ref(dst_name, dst_tail);
1143                         hashcpy(dst_peer->new_sha1, src->new_sha1);
1144                 }
1145                 dst_peer->peer_ref = copy_ref(src);
1146                 dst_peer->force = pat->force;
1147         free_name:
1148                 free(dst_name);
1149         }
1150         if (errs)
1151                 return -1;
1152         return 0;
1153 }
1154
1155 struct branch *branch_get(const char *name)
1156 {
1157         struct branch *ret;
1158
1159         read_config();
1160         if (!name || !*name || !strcmp(name, "HEAD"))
1161                 ret = current_branch;
1162         else
1163                 ret = make_branch(name, 0);
1164         if (ret && ret->remote_name) {
1165                 ret->remote = remote_get(ret->remote_name);
1166                 if (ret->merge_nr) {
1167                         int i;
1168                         ret->merge = xcalloc(sizeof(*ret->merge),
1169                                              ret->merge_nr);
1170                         for (i = 0; i < ret->merge_nr; i++) {
1171                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1172                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1173                                 remote_find_tracking(ret->remote,
1174                                                      ret->merge[i]);
1175                         }
1176                 }
1177         }
1178         return ret;
1179 }
1180
1181 int branch_has_merge_config(struct branch *branch)
1182 {
1183         return branch && !!branch->merge;
1184 }
1185
1186 int branch_merge_matches(struct branch *branch,
1187                                  int i,
1188                                  const char *refname)
1189 {
1190         if (!branch || i < 0 || i >= branch->merge_nr)
1191                 return 0;
1192         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1193 }
1194
1195 static struct ref *get_expanded_map(const struct ref *remote_refs,
1196                                     const struct refspec *refspec)
1197 {
1198         const struct ref *ref;
1199         struct ref *ret = NULL;
1200         struct ref **tail = &ret;
1201
1202         char *expn_name;
1203
1204         for (ref = remote_refs; ref; ref = ref->next) {
1205                 if (strchr(ref->name, '^'))
1206                         continue; /* a dereference item */
1207                 if (match_name_with_pattern(refspec->src, ref->name,
1208                                             refspec->dst, &expn_name)) {
1209                         struct ref *cpy = copy_ref(ref);
1210
1211                         cpy->peer_ref = alloc_ref(expn_name);
1212                         free(expn_name);
1213                         if (refspec->force)
1214                                 cpy->peer_ref->force = 1;
1215                         *tail = cpy;
1216                         tail = &cpy->next;
1217                 }
1218         }
1219
1220         return ret;
1221 }
1222
1223 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1224 {
1225         const struct ref *ref;
1226         for (ref = refs; ref; ref = ref->next) {
1227                 if (refname_match(name, ref->name, ref_fetch_rules))
1228                         return ref;
1229         }
1230         return NULL;
1231 }
1232
1233 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1234 {
1235         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1236
1237         if (!ref)
1238                 return NULL;
1239
1240         return copy_ref(ref);
1241 }
1242
1243 static struct ref *get_local_ref(const char *name)
1244 {
1245         if (!name)
1246                 return NULL;
1247
1248         if (!prefixcmp(name, "refs/"))
1249                 return alloc_ref(name);
1250
1251         if (!prefixcmp(name, "heads/") ||
1252             !prefixcmp(name, "tags/") ||
1253             !prefixcmp(name, "remotes/"))
1254                 return alloc_ref_with_prefix("refs/", 5, name);
1255
1256         return alloc_ref_with_prefix("refs/heads/", 11, name);
1257 }
1258
1259 int get_fetch_map(const struct ref *remote_refs,
1260                   const struct refspec *refspec,
1261                   struct ref ***tail,
1262                   int missing_ok)
1263 {
1264         struct ref *ref_map, **rmp;
1265
1266         if (refspec->pattern) {
1267                 ref_map = get_expanded_map(remote_refs, refspec);
1268         } else {
1269                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1270
1271                 ref_map = get_remote_ref(remote_refs, name);
1272                 if (!missing_ok && !ref_map)
1273                         die("Couldn't find remote ref %s", name);
1274                 if (ref_map) {
1275                         ref_map->peer_ref = get_local_ref(refspec->dst);
1276                         if (ref_map->peer_ref && refspec->force)
1277                                 ref_map->peer_ref->force = 1;
1278                 }
1279         }
1280
1281         for (rmp = &ref_map; *rmp; ) {
1282                 if ((*rmp)->peer_ref) {
1283                         int st = check_ref_format((*rmp)->peer_ref->name + 5);
1284                         if (st && st != CHECK_REF_FORMAT_ONELEVEL) {
1285                                 struct ref *ignore = *rmp;
1286                                 error("* Ignoring funny ref '%s' locally",
1287                                       (*rmp)->peer_ref->name);
1288                                 *rmp = (*rmp)->next;
1289                                 free(ignore->peer_ref);
1290                                 free(ignore);
1291                                 continue;
1292                         }
1293                 }
1294                 rmp = &((*rmp)->next);
1295         }
1296
1297         if (ref_map)
1298                 tail_link_ref(ref_map, tail);
1299
1300         return 0;
1301 }
1302
1303 int resolve_remote_symref(struct ref *ref, struct ref *list)
1304 {
1305         if (!ref->symref)
1306                 return 0;
1307         for (; list; list = list->next)
1308                 if (!strcmp(ref->symref, list->name)) {
1309                         hashcpy(ref->old_sha1, list->old_sha1);
1310                         return 0;
1311                 }
1312         return 1;
1313 }
1314
1315 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1316 {
1317         while (list) {
1318                 struct commit_list *temp = list;
1319                 temp->item->object.flags &= ~mark;
1320                 list = temp->next;
1321                 free(temp);
1322         }
1323 }
1324
1325 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1326 {
1327         struct object *o;
1328         struct commit *old, *new;
1329         struct commit_list *list, *used;
1330         int found = 0;
1331
1332         /* Both new and old must be commit-ish and new is descendant of
1333          * old.  Otherwise we require --force.
1334          */
1335         o = deref_tag(parse_object(old_sha1), NULL, 0);
1336         if (!o || o->type != OBJ_COMMIT)
1337                 return 0;
1338         old = (struct commit *) o;
1339
1340         o = deref_tag(parse_object(new_sha1), NULL, 0);
1341         if (!o || o->type != OBJ_COMMIT)
1342                 return 0;
1343         new = (struct commit *) o;
1344
1345         if (parse_commit(new) < 0)
1346                 return 0;
1347
1348         used = list = NULL;
1349         commit_list_insert(new, &list);
1350         while (list) {
1351                 new = pop_most_recent_commit(&list, TMP_MARK);
1352                 commit_list_insert(new, &used);
1353                 if (new == old) {
1354                         found = 1;
1355                         break;
1356                 }
1357         }
1358         unmark_and_free(list, TMP_MARK);
1359         unmark_and_free(used, TMP_MARK);
1360         return found;
1361 }
1362
1363 /*
1364  * Return true if there is anything to report, otherwise false.
1365  */
1366 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1367 {
1368         unsigned char sha1[20];
1369         struct commit *ours, *theirs;
1370         char symmetric[84];
1371         struct rev_info revs;
1372         const char *rev_argv[10], *base;
1373         int rev_argc;
1374
1375         /*
1376          * Nothing to report unless we are marked to build on top of
1377          * somebody else.
1378          */
1379         if (!branch ||
1380             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1381                 return 0;
1382
1383         /*
1384          * If what we used to build on no longer exists, there is
1385          * nothing to report.
1386          */
1387         base = branch->merge[0]->dst;
1388         if (!resolve_ref(base, sha1, 1, NULL))
1389                 return 0;
1390         theirs = lookup_commit(sha1);
1391         if (!theirs)
1392                 return 0;
1393
1394         if (!resolve_ref(branch->refname, sha1, 1, NULL))
1395                 return 0;
1396         ours = lookup_commit(sha1);
1397         if (!ours)
1398                 return 0;
1399
1400         /* are we the same? */
1401         if (theirs == ours)
1402                 return 0;
1403
1404         /* Run "rev-list --no-merges --left-right ours...theirs" internally... */
1405         rev_argc = 0;
1406         rev_argv[rev_argc++] = NULL;
1407         rev_argv[rev_argc++] = "--no-merges";
1408         rev_argv[rev_argc++] = "--left-right";
1409         rev_argv[rev_argc++] = symmetric;
1410         rev_argv[rev_argc++] = "--";
1411         rev_argv[rev_argc] = NULL;
1412
1413         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1414         strcpy(symmetric + 40, "...");
1415         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1416
1417         init_revisions(&revs, NULL);
1418         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1419         prepare_revision_walk(&revs);
1420
1421         /* ... and count the commits on each side. */
1422         *num_ours = 0;
1423         *num_theirs = 0;
1424         while (1) {
1425                 struct commit *c = get_revision(&revs);
1426                 if (!c)
1427                         break;
1428                 if (c->object.flags & SYMMETRIC_LEFT)
1429                         (*num_ours)++;
1430                 else
1431                         (*num_theirs)++;
1432         }
1433
1434         /* clear object flags smudged by the above traversal */
1435         clear_commit_marks(ours, ALL_REV_FLAGS);
1436         clear_commit_marks(theirs, ALL_REV_FLAGS);
1437         return 1;
1438 }
1439
1440 /*
1441  * Return true when there is anything to report, otherwise false.
1442  */
1443 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1444 {
1445         int num_ours, num_theirs;
1446         const char *base;
1447
1448         if (!stat_tracking_info(branch, &num_ours, &num_theirs))
1449                 return 0;
1450
1451         base = branch->merge[0]->dst;
1452         if (!prefixcmp(base, "refs/remotes/")) {
1453                 base += strlen("refs/remotes/");
1454         }
1455         if (!num_theirs)
1456                 strbuf_addf(sb, "Your branch is ahead of '%s' "
1457                             "by %d commit%s.\n",
1458                             base, num_ours, (num_ours == 1) ? "" : "s");
1459         else if (!num_ours)
1460                 strbuf_addf(sb, "Your branch is behind '%s' "
1461                             "by %d commit%s, "
1462                             "and can be fast-forwarded.\n",
1463                             base, num_theirs, (num_theirs == 1) ? "" : "s");
1464         else
1465                 strbuf_addf(sb, "Your branch and '%s' have diverged,\n"
1466                             "and have %d and %d different commit(s) each, "
1467                             "respectively.\n",
1468                             base, num_ours, num_theirs);
1469         return 1;
1470 }
1471
1472 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1473 {
1474         struct ref ***local_tail = cb_data;
1475         struct ref *ref;
1476         int len;
1477
1478         /* we already know it starts with refs/ to get here */
1479         if (check_ref_format(refname + 5))
1480                 return 0;
1481
1482         len = strlen(refname) + 1;
1483         ref = xcalloc(1, sizeof(*ref) + len);
1484         hashcpy(ref->new_sha1, sha1);
1485         memcpy(ref->name, refname, len);
1486         **local_tail = ref;
1487         *local_tail = &ref->next;
1488         return 0;
1489 }
1490
1491 struct ref *get_local_heads(void)
1492 {
1493         struct ref *local_refs, **local_tail = &local_refs;
1494         for_each_ref(one_local_ref, &local_tail);
1495         return local_refs;
1496 }
1497
1498 struct ref *guess_remote_head(const struct ref *head,
1499                               const struct ref *refs,
1500                               int all)
1501 {
1502         const struct ref *r;
1503         struct ref *list = NULL;
1504         struct ref **tail = &list;
1505
1506         if (!head)
1507                 return NULL;
1508
1509         /*
1510          * Some transports support directly peeking at
1511          * where HEAD points; if that is the case, then
1512          * we don't have to guess.
1513          */
1514         if (head->symref)
1515                 return copy_ref(find_ref_by_name(refs, head->symref));
1516
1517         /* If refs/heads/master could be right, it is. */
1518         if (!all) {
1519                 r = find_ref_by_name(refs, "refs/heads/master");
1520                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1521                         return copy_ref(r);
1522         }
1523
1524         /* Look for another ref that points there */
1525         for (r = refs; r; r = r->next) {
1526                 if (r != head && !hashcmp(r->old_sha1, head->old_sha1)) {
1527                         *tail = copy_ref(r);
1528                         tail = &((*tail)->next);
1529                         if (!all)
1530                                 break;
1531                 }
1532         }
1533
1534         return list;
1535 }