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