remote.c

   1 #include "cache.h"
   2 #include "remote.h"
   3 #include "refs.h"
   4 #include "commit.h"
   5 #include "diff.h"
   6 #include "revision.h"
   7 #include "dir.h"
   8 #include "tag.h"
   9 #include "string-list.h"
  10
  11 static struct refspec s_tag_refspec = {
  12         0,
  13         1,
  14         0,
  15         "refs/tags/*",
  16         "refs/tags/*"
  17 };
  18
  19 const struct refspec *tag_refspec = &s_tag_refspec;
  20
  21 struct counted_string {
  22         size_t len;
  23         const char *s;
  24 };
  25 struct rewrite {
  26         const char *base;
  27         size_t baselen;
  28         struct counted_string *instead_of;
  29         int instead_of_nr;
  30         int instead_of_alloc;
  31 };
  32 struct rewrites {
  33         struct rewrite **rewrite;
  34         int rewrite_alloc;
  35         int rewrite_nr;
  36 };
  37
  38 static struct remote **remotes;
  39 static int remotes_alloc;
  40 static int remotes_nr;
  41
  42 static struct branch **branches;
  43 static int branches_alloc;
  44 static int branches_nr;
  45
  46 static struct branch *current_branch;
  47 static const char *default_remote_name;
  48 static int explicit_default_remote_name;
  49
  50 static struct rewrites rewrites;
  51 static struct rewrites rewrites_push;
  52
  53 #define BUF_SIZE (2048)
  54 static char buffer[BUF_SIZE];
  55
  56 static const char *alias_url(const char *url, struct rewrites *r)
  57 {
  58         int i, j;
  59         char *ret;
  60         struct counted_string *longest;
  61         int longest_i;
  62
  63         longest = NULL;
  64         longest_i = -1;
  65         for (i = 0; i < r->rewrite_nr; i++) {
  66                 if (!r->rewrite[i])
  67                         continue;
  68                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  69                         if (!prefixcmp(url, r->rewrite[i]->instead_of[j].s) &&
  70                             (!longest ||
  71                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  72                                 longest = &(r->rewrite[i]->instead_of[j]);
  73                                 longest_i = i;
  74                         }
  75                 }
  76         }
  77         if (!longest)
  78                 return url;
  79
  80         ret = xmalloc(r->rewrite[longest_i]->baselen +
  81                      (strlen(url) - longest->len) + 1);
  82         strcpy(ret, r->rewrite[longest_i]->base);
  83         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
  84         return ret;
  85 }
  86
  87 static void add_push_refspec(struct remote *remote, const char *ref)
  88 {
  89         ALLOC_GROW(remote->push_refspec,
  90                    remote->push_refspec_nr + 1,
  91                    remote->push_refspec_alloc);
  92         remote->push_refspec[remote->push_refspec_nr++] = ref;
  93 }
  94
  95 static void add_fetch_refspec(struct remote *remote, const char *ref)
  96 {
  97         ALLOC_GROW(remote->fetch_refspec,
  98                    remote->fetch_refspec_nr + 1,
  99                    remote->fetch_refspec_alloc);
 100         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
 101 }
 102
 103 static void add_url(struct remote *remote, const char *url)
 104 {
 105         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
 106         remote->url[remote->url_nr++] = url;
 107 }
 108
 109 static void add_pushurl(struct remote *remote, const char *pushurl)
 110 {
 111         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
 112         remote->pushurl[remote->pushurl_nr++] = pushurl;
 113 }
 114
 115 static void add_pushurl_alias(struct remote *remote, const char *url)
 116 {
 117         const char *pushurl = alias_url(url, &rewrites_push);
 118         if (pushurl != url)
 119                 add_pushurl(remote, pushurl);
 120 }
 121
 122 static void add_url_alias(struct remote *remote, const char *url)
 123 {
 124         add_url(remote, alias_url(url, &rewrites));
 125         add_pushurl_alias(remote, url);
 126 }
 127
 128 static struct remote *make_remote(const char *name, int len)
 129 {
 130         struct remote *ret;
 131         int i;
 132
 133         for (i = 0; i < remotes_nr; i++) {
 134                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
 135                            !remotes[i]->name[len]) :
 136                     !strcmp(name, remotes[i]->name))
 137                         return remotes[i];
 138         }
 139
 140         ret = xcalloc(1, sizeof(struct remote));
 141         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 142         remotes[remotes_nr++] = ret;
 143         if (len)
 144                 ret->name = xstrndup(name, len);
 145         else
 146                 ret->name = xstrdup(name);
 147         return ret;
 148 }
 149
 150 static void add_merge(struct branch *branch, const char *name)
 151 {
 152         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 153                    branch->merge_alloc);
 154         branch->merge_name[branch->merge_nr++] = name;
 155 }
 156
 157 static struct branch *make_branch(const char *name, int len)
 158 {
 159         struct branch *ret;
 160         int i;
 161         char *refname;
 162
 163         for (i = 0; i < branches_nr; i++) {
 164                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 165                            !branches[i]->name[len]) :
 166                     !strcmp(name, branches[i]->name))
 167                         return branches[i];
 168         }
 169
 170         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 171         ret = xcalloc(1, sizeof(struct branch));
 172         branches[branches_nr++] = ret;
 173         if (len)
 174                 ret->name = xstrndup(name, len);
 175         else
 176                 ret->name = xstrdup(name);
 177         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
 178         strcpy(refname, "refs/heads/");
 179         strcpy(refname + strlen("refs/heads/"), ret->name);
 180         ret->refname = refname;
 181
 182         return ret;
 183 }
 184
 185 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 186 {
 187         struct rewrite *ret;
 188         int i;
 189
 190         for (i = 0; i < r->rewrite_nr; i++) {
 191                 if (len
 192                     ? (len == r->rewrite[i]->baselen &&
 193                        !strncmp(base, r->rewrite[i]->base, len))
 194                     : !strcmp(base, r->rewrite[i]->base))
 195                         return r->rewrite[i];
 196         }
 197
 198         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 199         ret = xcalloc(1, sizeof(struct rewrite));
 200         r->rewrite[r->rewrite_nr++] = ret;
 201         if (len) {
 202                 ret->base = xstrndup(base, len);
 203                 ret->baselen = len;
 204         }
 205         else {
 206                 ret->base = xstrdup(base);
 207                 ret->baselen = strlen(base);
 208         }
 209         return ret;
 210 }
 211
 212 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 213 {
 214         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 215         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 216         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 217         rewrite->instead_of_nr++;
 218 }
 219
 220 static void read_remotes_file(struct remote *remote)
 221 {
 222         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 223
 224         if (!f)
 225                 return;
 226         remote->origin = REMOTE_REMOTES;
 227         while (fgets(buffer, BUF_SIZE, f)) {
 228                 int value_list;
 229                 char *s, *p;
 230
 231                 if (!prefixcmp(buffer, "URL:")) {
 232                         value_list = 0;
 233                         s = buffer + 4;
 234                 } else if (!prefixcmp(buffer, "Push:")) {
 235                         value_list = 1;
 236                         s = buffer + 5;
 237                 } else if (!prefixcmp(buffer, "Pull:")) {
 238                         value_list = 2;
 239                         s = buffer + 5;
 240                 } else
 241                         continue;
 242
 243                 while (isspace(*s))
 244                         s++;
 245                 if (!*s)
 246                         continue;
 247
 248                 p = s + strlen(s);
 249                 while (isspace(p[-1]))
 250                         *--p = 0;
 251
 252                 switch (value_list) {
 253                 case 0:
 254                         add_url_alias(remote, xstrdup(s));
 255                         break;
 256                 case 1:
 257                         add_push_refspec(remote, xstrdup(s));
 258                         break;
 259                 case 2:
 260                         add_fetch_refspec(remote, xstrdup(s));
 261                         break;
 262                 }
 263         }
 264         fclose(f);
 265 }
 266
 267 static void read_branches_file(struct remote *remote)
 268 {
 269         const char *slash = strchr(remote->name, '/');
 270         char *frag;
 271         struct strbuf branch = STRBUF_INIT;
 272         int n = slash ? slash - remote->name : 1000;
 273         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
 274         char *s, *p;
 275         int len;
 276
 277         if (!f)
 278                 return;
 279         s = fgets(buffer, BUF_SIZE, f);
 280         fclose(f);
 281         if (!s)
 282                 return;
 283         while (isspace(*s))
 284                 s++;
 285         if (!*s)
 286                 return;
 287         remote->origin = REMOTE_BRANCHES;
 288         p = s + strlen(s);
 289         while (isspace(p[-1]))
 290                 *--p = 0;
 291         len = p - s;
 292         if (slash)
 293                 len += strlen(slash);
 294         p = xmalloc(len + 1);
 295         strcpy(p, s);
 296         if (slash)
 297                 strcat(p, slash);
 298
 299         /*
 300          * With "slash", e.g. "git fetch jgarzik/netdev-2.6" when
 301          * reading from $GIT_DIR/branches/jgarzik fetches "HEAD" from
 302          * the partial URL obtained from the branches file plus
 303          * "/netdev-2.6" and does not store it in any tracking ref.
 304          * #branch specifier in the file is ignored.
 305          *
 306          * Otherwise, the branches file would have URL and optionally
 307          * #branch specified.  The "master" (or specified) branch is
 308          * fetched and stored in the local branch of the same name.
 309          */
 310         frag = strchr(p, '#');
 311         if (frag) {
 312                 *(frag++) = '\0';
 313                 strbuf_addf(&branch, "refs/heads/%s", frag);
 314         } else
 315                 strbuf_addstr(&branch, "refs/heads/master");
 316         if (!slash) {
 317                 strbuf_addf(&branch, ":refs/heads/%s", remote->name);
 318         } else {
 319                 strbuf_reset(&branch);
 320                 strbuf_addstr(&branch, "HEAD:");
 321         }
 322         add_url_alias(remote, p);
 323         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
 324         /*
 325          * Cogito compatible push: push current HEAD to remote #branch
 326          * (master if missing)
 327          */
 328         strbuf_init(&branch, 0);
 329         strbuf_addstr(&branch, "HEAD");
 330         if (frag)
 331                 strbuf_addf(&branch, ":refs/heads/%s", frag);
 332         else
 333                 strbuf_addstr(&branch, ":refs/heads/master");
 334         add_push_refspec(remote, strbuf_detach(&branch, NULL));
 335         remote->fetch_tags = 1; /* always auto-follow */
 336 }
 337
 338 static int handle_config(const char *key, const char *value, void *cb)
 339 {
 340         const char *name;
 341         const char *subkey;
 342         struct remote *remote;
 343         struct branch *branch;
 344         if (!prefixcmp(key, "branch.")) {
 345                 name = key + 7;
 346                 subkey = strrchr(name, '.');
 347                 if (!subkey)
 348                         return 0;
 349                 branch = make_branch(name, subkey - name);
 350                 if (!strcmp(subkey, ".remote")) {
 351                         if (!value)
 352                                 return config_error_nonbool(key);
 353                         branch->remote_name = xstrdup(value);
 354                         if (branch == current_branch) {
 355                                 default_remote_name = branch->remote_name;
 356                                 explicit_default_remote_name = 1;
 357                         }
 358                 } else if (!strcmp(subkey, ".merge")) {
 359                         if (!value)
 360                                 return config_error_nonbool(key);
 361                         add_merge(branch, xstrdup(value));
 362                 }
 363                 return 0;
 364         }
 365         if (!prefixcmp(key, "url.")) {
 366                 struct rewrite *rewrite;
 367                 name = key + 4;
 368                 subkey = strrchr(name, '.');
 369                 if (!subkey)
 370                         return 0;
 371                 if (!strcmp(subkey, ".insteadof")) {
 372                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 373                         if (!value)
 374                                 return config_error_nonbool(key);
 375                         add_instead_of(rewrite, xstrdup(value));
 376                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 377                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 378                         if (!value)
 379                                 return config_error_nonbool(key);
 380                         add_instead_of(rewrite, xstrdup(value));
 381                 }
 382         }
 383         if (prefixcmp(key,  "remote."))
 384                 return 0;
 385         name = key + 7;
 386         if (*name == '/') {
 387                 warning("Config remote shorthand cannot begin with '/': %s",
 388                         name);
 389                 return 0;
 390         }
 391         subkey = strrchr(name, '.');
 392         if (!subkey)
 393                 return 0;
 394         remote = make_remote(name, subkey - name);
 395         remote->origin = REMOTE_CONFIG;
 396         if (!strcmp(subkey, ".mirror"))
 397                 remote->mirror = git_config_bool(key, value);
 398         else if (!strcmp(subkey, ".skipdefaultupdate"))
 399                 remote->skip_default_update = git_config_bool(key, value);
 400
 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 string_list refs = { NULL, 0, 0, 0 };
 739         struct string_list_item *item = NULL;
 740         struct ref *prev = NULL, *next = NULL;
 741         for (; ref_map; prev = ref_map, ref_map = next) {
 742                 next = ref_map->next;
 743                 if (!ref_map->peer_ref)
 744                         continue;
 745
 746                 item = string_list_lookup(ref_map->peer_ref->name, &refs);
 747                 if (item) {
 748                         if (strcmp(((struct ref *)item->util)->name,
 749                                    ref_map->name))
 750                                 die("%s tracks both %s and %s",
 751                                     ref_map->peer_ref->name,
 752                                     ((struct ref *)item->util)->name,
 753                                     ref_map->name);
 754                         prev->next = ref_map->next;
 755                         free(ref_map->peer_ref);
 756                         free(ref_map);
 757                         ref_map = prev; /* skip this; we freed it */
 758                         continue;
 759                 }
 760
 761                 item = string_list_insert(ref_map->peer_ref->name, &refs);
 762                 item->util = ref_map;
 763         }
 764         string_list_clear(&refs, 0);
 765 }
 766
 767 int remote_has_url(struct remote *remote, const char *url)
 768 {
 769         int i;
 770         for (i = 0; i < remote->url_nr; i++) {
 771                 if (!strcmp(remote->url[i], url))
 772                         return 1;
 773         }
 774         return 0;
 775 }
 776
 777 static int match_name_with_pattern(const char *key, const char *name,
 778                                    const char *value, char **result)
 779 {
 780         const char *kstar = strchr(key, '*');
 781         size_t klen;
 782         size_t ksuffixlen;
 783         size_t namelen;
 784         int ret;
 785         if (!kstar)
 786                 die("Key '%s' of pattern had no '*'", key);
 787         klen = kstar - key;
 788         ksuffixlen = strlen(kstar + 1);
 789         namelen = strlen(name);
 790         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 791                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 792         if (ret && value) {
 793                 const char *vstar = strchr(value, '*');
 794                 size_t vlen;
 795                 size_t vsuffixlen;
 796                 if (!vstar)
 797                         die("Value '%s' of pattern has no '*'", value);
 798                 vlen = vstar - value;
 799                 vsuffixlen = strlen(vstar + 1);
 800                 *result = xmalloc(vlen + vsuffixlen +
 801                                   strlen(name) -
 802                                   klen - ksuffixlen + 1);
 803                 strncpy(*result, value, vlen);
 804                 strncpy(*result + vlen,
 805                         name + klen, namelen - klen - ksuffixlen);
 806                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
 807                        vstar + 1);
 808         }
 809         return ret;
 810 }
 811
 812 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 813 {
 814         int find_src = refspec->src == NULL;
 815         char *needle, **result;
 816         int i;
 817
 818         if (find_src) {
 819                 if (!refspec->dst)
 820                         return error("find_tracking: need either src or dst");
 821                 needle = refspec->dst;
 822                 result = &refspec->src;
 823         } else {
 824                 needle = refspec->src;
 825                 result = &refspec->dst;
 826         }
 827
 828         for (i = 0; i < remote->fetch_refspec_nr; i++) {
 829                 struct refspec *fetch = &remote->fetch[i];
 830                 const char *key = find_src ? fetch->dst : fetch->src;
 831                 const char *value = find_src ? fetch->src : fetch->dst;
 832                 if (!fetch->dst)
 833                         continue;
 834                 if (fetch->pattern) {
 835                         if (match_name_with_pattern(key, needle, value, result)) {
 836                                 refspec->force = fetch->force;
 837                                 return 0;
 838                         }
 839                 } else if (!strcmp(needle, key)) {
 840                         *result = xstrdup(value);
 841                         refspec->force = fetch->force;
 842                         return 0;
 843                 }
 844         }
 845         return -1;
 846 }
 847
 848 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 849                 const char *name)
 850 {
 851         size_t len = strlen(name);
 852         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 853         memcpy(ref->name, prefix, prefixlen);
 854         memcpy(ref->name + prefixlen, name, len);
 855         return ref;
 856 }
 857
 858 struct ref *alloc_ref(const char *name)
 859 {
 860         return alloc_ref_with_prefix("", 0, name);
 861 }
 862
 863 static struct ref *copy_ref(const struct ref *ref)
 864 {
 865         struct ref *cpy;
 866         size_t len;
 867         if (!ref)
 868                 return NULL;
 869         len = strlen(ref->name);
 870         cpy = xmalloc(sizeof(struct ref) + len + 1);
 871         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 872         cpy->next = NULL;
 873         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 874         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 875         cpy->peer_ref = copy_ref(ref->peer_ref);
 876         return cpy;
 877 }
 878
 879 struct ref *copy_ref_list(const struct ref *ref)
 880 {
 881         struct ref *ret = NULL;
 882         struct ref **tail = &ret;
 883         while (ref) {
 884                 *tail = copy_ref(ref);
 885                 ref = ref->next;
 886                 tail = &((*tail)->next);
 887         }
 888         return ret;
 889 }
 890
 891 static void free_ref(struct ref *ref)
 892 {
 893         if (!ref)
 894                 return;
 895         free_ref(ref->peer_ref);
 896         free(ref->remote_status);
 897         free(ref->symref);
 898         free(ref);
 899 }
 900
 901 void free_refs(struct ref *ref)
 902 {
 903         struct ref *next;
 904         while (ref) {
 905                 next = ref->next;
 906                 free_ref(ref);
 907                 ref = next;
 908         }
 909 }
 910
 911 static int count_refspec_match(const char *pattern,
 912                                struct ref *refs,
 913                                struct ref **matched_ref)
 914 {
 915         int patlen = strlen(pattern);
 916         struct ref *matched_weak = NULL;
 917         struct ref *matched = NULL;
 918         int weak_match = 0;
 919         int match = 0;
 920
 921         for (weak_match = match = 0; refs; refs = refs->next) {
 922                 char *name = refs->name;
 923                 int namelen = strlen(name);
 924
 925                 if (!refname_match(pattern, name, ref_rev_parse_rules))
 926                         continue;
 927
 928                 /* A match is "weak" if it is with refs outside
 929                  * heads or tags, and did not specify the pattern
 930                  * in full (e.g. "refs/remotes/origin/master") or at
 931                  * least from the toplevel (e.g. "remotes/origin/master");
 932                  * otherwise "git push $URL master" would result in
 933                  * ambiguity between remotes/origin/master and heads/master
 934                  * at the remote site.
 935                  */
 936                 if (namelen != patlen &&
 937                     patlen != namelen - 5 &&
 938                     prefixcmp(name, "refs/heads/") &&
 939                     prefixcmp(name, "refs/tags/")) {
 940                         /* We want to catch the case where only weak
 941                          * matches are found and there are multiple
 942                          * matches, and where more than one strong
 943                          * matches are found, as ambiguous.  One
 944                          * strong match with zero or more weak matches
 945                          * are acceptable as a unique match.
 946                          */
 947                         matched_weak = refs;
 948                         weak_match++;
 949                 }
 950                 else {
 951                         matched = refs;
 952                         match++;
 953                 }
 954         }
 955         if (!matched) {
 956                 *matched_ref = matched_weak;
 957                 return weak_match;
 958         }
 959         else {
 960                 *matched_ref = matched;
 961                 return match;
 962         }
 963 }
 964
 965 static void tail_link_ref(struct ref *ref, struct ref ***tail)
 966 {
 967         **tail = ref;
 968         while (ref->next)
 969                 ref = ref->next;
 970         *tail = &ref->next;
 971 }
 972
 973 static struct ref *try_explicit_object_name(const char *name)
 974 {
 975         unsigned char sha1[20];
 976         struct ref *ref;
 977
 978         if (!*name) {
 979                 ref = alloc_ref("(delete)");
 980                 hashclr(ref->new_sha1);
 981                 return ref;
 982         }
 983         if (get_sha1(name, sha1))
 984                 return NULL;
 985         ref = alloc_ref(name);
 986         hashcpy(ref->new_sha1, sha1);
 987         return ref;
 988 }
 989
 990 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
 991 {
 992         struct ref *ret = alloc_ref(name);
 993         tail_link_ref(ret, tail);
 994         return ret;
 995 }
 996
 997 static char *guess_ref(const char *name, struct ref *peer)
 998 {
 999         struct strbuf buf = STRBUF_INIT;
1000         unsigned char sha1[20];
1001
1002         const char *r = resolve_ref(peer->name, sha1, 1, NULL);
1003         if (!r)
1004                 return NULL;
1005
1006         if (!prefixcmp(r, "refs/heads/"))
1007                 strbuf_addstr(&buf, "refs/heads/");
1008         else if (!prefixcmp(r, "refs/tags/"))
1009                 strbuf_addstr(&buf, "refs/tags/");
1010         else
1011                 return NULL;
1012
1013         strbuf_addstr(&buf, name);
1014         return strbuf_detach(&buf, NULL);
1015 }
1016
1017 static int match_explicit(struct ref *src, struct ref *dst,
1018                           struct ref ***dst_tail,
1019                           struct refspec *rs)
1020 {
1021         struct ref *matched_src, *matched_dst;
1022         int copy_src;
1023
1024         const char *dst_value = rs->dst;
1025         char *dst_guess;
1026
1027         if (rs->pattern || rs->matching)
1028                 return 0;
1029
1030         matched_src = matched_dst = NULL;
1031         switch (count_refspec_match(rs->src, src, &matched_src)) {
1032         case 1:
1033                 copy_src = 1;
1034                 break;
1035         case 0:
1036                 /* The source could be in the get_sha1() format
1037                  * not a reference name.  :refs/other is a
1038                  * way to delete 'other' ref at the remote end.
1039                  */
1040                 matched_src = try_explicit_object_name(rs->src);
1041                 if (!matched_src)
1042                         return error("src refspec %s does not match any.", rs->src);
1043                 copy_src = 0;
1044                 break;
1045         default:
1046                 return error("src refspec %s matches more than one.", rs->src);
1047         }
1048
1049         if (!dst_value) {
1050                 unsigned char sha1[20];
1051                 int flag;
1052
1053                 dst_value = resolve_ref(matched_src->name, sha1, 1, &flag);
1054                 if (!dst_value ||
1055                     ((flag & REF_ISSYMREF) &&
1056                      prefixcmp(dst_value, "refs/heads/")))
1057                         die("%s cannot be resolved to branch.",
1058                             matched_src->name);
1059         }
1060
1061         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1062         case 1:
1063                 break;
1064         case 0:
1065                 if (!memcmp(dst_value, "refs/", 5))
1066                         matched_dst = make_linked_ref(dst_value, dst_tail);
1067                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1068                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1069                 else
1070                         error("unable to push to unqualified destination: %s\n"
1071                               "The destination refspec neither matches an "
1072                               "existing ref on the remote nor\n"
1073                               "begins with refs/, and we are unable to "
1074                               "guess a prefix based on the source ref.",
1075                               dst_value);
1076                 break;
1077         default:
1078                 matched_dst = NULL;
1079                 error("dst refspec %s matches more than one.",
1080                       dst_value);
1081                 break;
1082         }
1083         if (!matched_dst)
1084                 return -1;
1085         if (matched_dst->peer_ref)
1086                 return error("dst ref %s receives from more than one src.",
1087                       matched_dst->name);
1088         else {
1089                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1090                 matched_dst->force = rs->force;
1091         }
1092         return 0;
1093 }
1094
1095 static int match_explicit_refs(struct ref *src, struct ref *dst,
1096                                struct ref ***dst_tail, struct refspec *rs,
1097                                int rs_nr)
1098 {
1099         int i, errs;
1100         for (i = errs = 0; i < rs_nr; i++)
1101                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1102         return errs;
1103 }
1104
1105 static const struct refspec *check_pattern_match(const struct refspec *rs,
1106                                                  int rs_nr,
1107                                                  const struct ref *src)
1108 {
1109         int i;
1110         int matching_refs = -1;
1111         for (i = 0; i < rs_nr; i++) {
1112                 if (rs[i].matching &&
1113                     (matching_refs == -1 || rs[i].force)) {
1114                         matching_refs = i;
1115                         continue;
1116                 }
1117
1118                 if (rs[i].pattern && match_name_with_pattern(rs[i].src, src->name,
1119                                                              NULL, NULL))
1120                         return rs + i;
1121         }
1122         if (matching_refs != -1)
1123                 return rs + matching_refs;
1124         else
1125                 return NULL;
1126 }
1127
1128 static struct ref **tail_ref(struct ref **head)
1129 {
1130         struct ref **tail = head;
1131         while (*tail)
1132                 tail = &((*tail)->next);
1133         return tail;
1134 }
1135
1136 /*
1137  * Note. This is used only by "push"; refspec matching rules for
1138  * push and fetch are subtly different, so do not try to reuse it
1139  * without thinking.
1140  */
1141 int match_refs(struct ref *src, struct ref **dst,
1142                int nr_refspec, const char **refspec, int flags)
1143 {
1144         struct refspec *rs;
1145         int send_all = flags & MATCH_REFS_ALL;
1146         int send_mirror = flags & MATCH_REFS_MIRROR;
1147         int errs;
1148         static const char *default_refspec[] = { ":", NULL };
1149         struct ref **dst_tail = tail_ref(dst);
1150
1151         if (!nr_refspec) {
1152                 nr_refspec = 1;
1153                 refspec = default_refspec;
1154         }
1155         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1156         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1157
1158         /* pick the remainder */
1159         for ( ; src; src = src->next) {
1160                 struct ref *dst_peer;
1161                 const struct refspec *pat = NULL;
1162                 char *dst_name;
1163                 if (src->peer_ref)
1164                         continue;
1165
1166                 pat = check_pattern_match(rs, nr_refspec, src);
1167                 if (!pat)
1168                         continue;
1169
1170                 if (pat->matching) {
1171                         /*
1172                          * "matching refs"; traditionally we pushed everything
1173                          * including refs outside refs/heads/ hierarchy, but
1174                          * that does not make much sense these days.
1175                          */
1176                         if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
1177                                 continue;
1178                         dst_name = xstrdup(src->name);
1179
1180                 } else {
1181                         const char *dst_side = pat->dst ? pat->dst : pat->src;
1182                         if (!match_name_with_pattern(pat->src, src->name,
1183                                                      dst_side, &dst_name))
1184                                 die("Didn't think it matches any more");
1185                 }
1186                 dst_peer = find_ref_by_name(*dst, dst_name);
1187                 if (dst_peer) {
1188                         if (dst_peer->peer_ref)
1189                                 /* We're already sending something to this ref. */
1190                                 goto free_name;
1191
1192                 } else {
1193                         if (pat->matching && !(send_all || send_mirror))
1194                                 /*
1195                                  * Remote doesn't have it, and we have no
1196                                  * explicit pattern, and we don't have
1197                                  * --all nor --mirror.
1198                                  */
1199                                 goto free_name;
1200
1201                         /* Create a new one and link it */
1202                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1203                         hashcpy(dst_peer->new_sha1, src->new_sha1);
1204                 }
1205                 dst_peer->peer_ref = copy_ref(src);
1206                 dst_peer->force = pat->force;
1207         free_name:
1208                 free(dst_name);
1209         }
1210         if (errs)
1211                 return -1;
1212         return 0;
1213 }
1214
1215 struct branch *branch_get(const char *name)
1216 {
1217         struct branch *ret;
1218
1219         read_config();
1220         if (!name || !*name || !strcmp(name, "HEAD"))
1221                 ret = current_branch;
1222         else
1223                 ret = make_branch(name, 0);
1224         if (ret && ret->remote_name) {
1225                 ret->remote = remote_get(ret->remote_name);
1226                 if (ret->merge_nr) {
1227                         int i;
1228                         ret->merge = xcalloc(sizeof(*ret->merge),
1229                                              ret->merge_nr);
1230                         for (i = 0; i < ret->merge_nr; i++) {
1231                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1232                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1233                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1234                                     && !strcmp(ret->remote_name, "."))
1235                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1236                         }
1237                 }
1238         }
1239         return ret;
1240 }
1241
1242 int branch_has_merge_config(struct branch *branch)
1243 {
1244         return branch && !!branch->merge;
1245 }
1246
1247 int branch_merge_matches(struct branch *branch,
1248                                  int i,
1249                                  const char *refname)
1250 {
1251         if (!branch || i < 0 || i >= branch->merge_nr)
1252                 return 0;
1253         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1254 }
1255
1256 static struct ref *get_expanded_map(const struct ref *remote_refs,
1257                                     const struct refspec *refspec)
1258 {
1259         const struct ref *ref;
1260         struct ref *ret = NULL;
1261         struct ref **tail = &ret;
1262
1263         char *expn_name;
1264
1265         for (ref = remote_refs; ref; ref = ref->next) {
1266                 if (strchr(ref->name, '^'))
1267                         continue; /* a dereference item */
1268                 if (match_name_with_pattern(refspec->src, ref->name,
1269                                             refspec->dst, &expn_name)) {
1270                         struct ref *cpy = copy_ref(ref);
1271
1272                         cpy->peer_ref = alloc_ref(expn_name);
1273                         free(expn_name);
1274                         if (refspec->force)
1275                                 cpy->peer_ref->force = 1;
1276                         *tail = cpy;
1277                         tail = &cpy->next;
1278                 }
1279         }
1280
1281         return ret;
1282 }
1283
1284 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1285 {
1286         const struct ref *ref;
1287         for (ref = refs; ref; ref = ref->next) {
1288                 if (refname_match(name, ref->name, ref_fetch_rules))
1289                         return ref;
1290         }
1291         return NULL;
1292 }
1293
1294 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1295 {
1296         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1297
1298         if (!ref)
1299                 return NULL;
1300
1301         return copy_ref(ref);
1302 }
1303
1304 static struct ref *get_local_ref(const char *name)
1305 {
1306         if (!name || name[0] == '\0')
1307                 return NULL;
1308
1309         if (!prefixcmp(name, "refs/"))
1310                 return alloc_ref(name);
1311
1312         if (!prefixcmp(name, "heads/") ||
1313             !prefixcmp(name, "tags/") ||
1314             !prefixcmp(name, "remotes/"))
1315                 return alloc_ref_with_prefix("refs/", 5, name);
1316
1317         return alloc_ref_with_prefix("refs/heads/", 11, name);
1318 }
1319
1320 int get_fetch_map(const struct ref *remote_refs,
1321                   const struct refspec *refspec,
1322                   struct ref ***tail,
1323                   int missing_ok)
1324 {
1325         struct ref *ref_map, **rmp;
1326
1327         if (refspec->pattern) {
1328                 ref_map = get_expanded_map(remote_refs, refspec);
1329         } else {
1330                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1331
1332                 ref_map = get_remote_ref(remote_refs, name);
1333                 if (!missing_ok && !ref_map)
1334                         die("Couldn't find remote ref %s", name);
1335                 if (ref_map) {
1336                         ref_map->peer_ref = get_local_ref(refspec->dst);
1337                         if (ref_map->peer_ref && refspec->force)
1338                                 ref_map->peer_ref->force = 1;
1339                 }
1340         }
1341
1342         for (rmp = &ref_map; *rmp; ) {
1343                 if ((*rmp)->peer_ref) {
1344                         int st = check_ref_format((*rmp)->peer_ref->name + 5);
1345                         if (st && st != CHECK_REF_FORMAT_ONELEVEL) {
1346                                 struct ref *ignore = *rmp;
1347                                 error("* Ignoring funny ref '%s' locally",
1348                                       (*rmp)->peer_ref->name);
1349                                 *rmp = (*rmp)->next;
1350                                 free(ignore->peer_ref);
1351                                 free(ignore);
1352                                 continue;
1353                         }
1354                 }
1355                 rmp = &((*rmp)->next);
1356         }
1357
1358         if (ref_map)
1359                 tail_link_ref(ref_map, tail);
1360
1361         return 0;
1362 }
1363
1364 int resolve_remote_symref(struct ref *ref, struct ref *list)
1365 {
1366         if (!ref->symref)
1367                 return 0;
1368         for (; list; list = list->next)
1369                 if (!strcmp(ref->symref, list->name)) {
1370                         hashcpy(ref->old_sha1, list->old_sha1);
1371                         return 0;
1372                 }
1373         return 1;
1374 }
1375
1376 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1377 {
1378         while (list) {
1379                 struct commit_list *temp = list;
1380                 temp->item->object.flags &= ~mark;
1381                 list = temp->next;
1382                 free(temp);
1383         }
1384 }
1385
1386 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1387 {
1388         struct object *o;
1389         struct commit *old, *new;
1390         struct commit_list *list, *used;
1391         int found = 0;
1392
1393         /* Both new and old must be commit-ish and new is descendant of
1394          * old.  Otherwise we require --force.
1395          */
1396         o = deref_tag(parse_object(old_sha1), NULL, 0);
1397         if (!o || o->type != OBJ_COMMIT)
1398                 return 0;
1399         old = (struct commit *) o;
1400
1401         o = deref_tag(parse_object(new_sha1), NULL, 0);
1402         if (!o || o->type != OBJ_COMMIT)
1403                 return 0;
1404         new = (struct commit *) o;
1405
1406         if (parse_commit(new) < 0)
1407                 return 0;
1408
1409         used = list = NULL;
1410         commit_list_insert(new, &list);
1411         while (list) {
1412                 new = pop_most_recent_commit(&list, TMP_MARK);
1413                 commit_list_insert(new, &used);
1414                 if (new == old) {
1415                         found = 1;
1416                         break;
1417                 }
1418         }
1419         unmark_and_free(list, TMP_MARK);
1420         unmark_and_free(used, TMP_MARK);
1421         return found;
1422 }
1423
1424 /*
1425  * Return true if there is anything to report, otherwise false.
1426  */
1427 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1428 {
1429         unsigned char sha1[20];
1430         struct commit *ours, *theirs;
1431         char symmetric[84];
1432         struct rev_info revs;
1433         const char *rev_argv[10], *base;
1434         int rev_argc;
1435
1436         /*
1437          * Nothing to report unless we are marked to build on top of
1438          * somebody else.
1439          */
1440         if (!branch ||
1441             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1442                 return 0;
1443
1444         /*
1445          * If what we used to build on no longer exists, there is
1446          * nothing to report.
1447          */
1448         base = branch->merge[0]->dst;
1449         if (!resolve_ref(base, sha1, 1, NULL))
1450                 return 0;
1451         theirs = lookup_commit_reference(sha1);
1452         if (!theirs)
1453                 return 0;
1454
1455         if (!resolve_ref(branch->refname, sha1, 1, NULL))
1456                 return 0;
1457         ours = lookup_commit_reference(sha1);
1458         if (!ours)
1459                 return 0;
1460
1461         /* are we the same? */
1462         if (theirs == ours)
1463                 return 0;
1464
1465         /* Run "rev-list --left-right ours...theirs" internally... */
1466         rev_argc = 0;
1467         rev_argv[rev_argc++] = NULL;
1468         rev_argv[rev_argc++] = "--left-right";
1469         rev_argv[rev_argc++] = symmetric;
1470         rev_argv[rev_argc++] = "--";
1471         rev_argv[rev_argc] = NULL;
1472
1473         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1474         strcpy(symmetric + 40, "...");
1475         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1476
1477         init_revisions(&revs, NULL);
1478         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1479         prepare_revision_walk(&revs);
1480
1481         /* ... and count the commits on each side. */
1482         *num_ours = 0;
1483         *num_theirs = 0;
1484         while (1) {
1485                 struct commit *c = get_revision(&revs);
1486                 if (!c)
1487                         break;
1488                 if (c->object.flags & SYMMETRIC_LEFT)
1489                         (*num_ours)++;
1490                 else
1491                         (*num_theirs)++;
1492         }
1493
1494         /* clear object flags smudged by the above traversal */
1495         clear_commit_marks(ours, ALL_REV_FLAGS);
1496         clear_commit_marks(theirs, ALL_REV_FLAGS);
1497         return 1;
1498 }
1499
1500 /*
1501  * Return true when there is anything to report, otherwise false.
1502  */
1503 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1504 {
1505         int num_ours, num_theirs;
1506         const char *base;
1507
1508         if (!stat_tracking_info(branch, &num_ours, &num_theirs))
1509                 return 0;
1510
1511         base = branch->merge[0]->dst;
1512         base = shorten_unambiguous_ref(base, 0);
1513         if (!num_theirs)
1514                 strbuf_addf(sb, "Your branch is ahead of '%s' "
1515                             "by %d commit%s.\n",
1516                             base, num_ours, (num_ours == 1) ? "" : "s");
1517         else if (!num_ours)
1518                 strbuf_addf(sb, "Your branch is behind '%s' "
1519                             "by %d commit%s, "
1520                             "and can be fast-forwarded.\n",
1521                             base, num_theirs, (num_theirs == 1) ? "" : "s");
1522         else
1523                 strbuf_addf(sb, "Your branch and '%s' have diverged,\n"
1524                             "and have %d and %d different commit(s) each, "
1525                             "respectively.\n",
1526                             base, num_ours, num_theirs);
1527         return 1;
1528 }
1529
1530 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1531 {
1532         struct ref ***local_tail = cb_data;
1533         struct ref *ref;
1534         int len;
1535
1536         /* we already know it starts with refs/ to get here */
1537         if (check_ref_format(refname + 5))
1538                 return 0;
1539
1540         len = strlen(refname) + 1;
1541         ref = xcalloc(1, sizeof(*ref) + len);
1542         hashcpy(ref->new_sha1, sha1);
1543         memcpy(ref->name, refname, len);
1544         **local_tail = ref;
1545         *local_tail = &ref->next;
1546         return 0;
1547 }
1548
1549 struct ref *get_local_heads(void)
1550 {
1551         struct ref *local_refs = NULL, **local_tail = &local_refs;
1552         for_each_ref(one_local_ref, &local_tail);
1553         return local_refs;
1554 }
1555
1556 struct ref *guess_remote_head(const struct ref *head,
1557                               const struct ref *refs,
1558                               int all)
1559 {
1560         const struct ref *r;
1561         struct ref *list = NULL;
1562         struct ref **tail = &list;
1563
1564         if (!head)
1565                 return NULL;
1566
1567         /*
1568          * Some transports support directly peeking at
1569          * where HEAD points; if that is the case, then
1570          * we don't have to guess.
1571          */
1572         if (head->symref)
1573                 return copy_ref(find_ref_by_name(refs, head->symref));
1574
1575         /* If refs/heads/master could be right, it is. */
1576         if (!all) {
1577                 r = find_ref_by_name(refs, "refs/heads/master");
1578                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1579                         return copy_ref(r);
1580         }
1581
1582         /* Look for another ref that points there */
1583         for (r = refs; r; r = r->next) {
1584                 if (r != head && !hashcmp(r->old_sha1, head->old_sha1)) {
1585                         *tail = copy_ref(r);
1586                         tail = &((*tail)->next);
1587                         if (!all)
1588                                 break;
1589                 }
1590         }
1591
1592         return list;
1593 }