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