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
  56 static int valid_remote(const struct remote *remote)
  57 {
  58         return !remote->url != !remote->foreign_vcs;
  59 }
  60
  61 static const char *alias_url(const char *url, struct rewrites *r)
  62 {
  63         int i, j;
  64         char *ret;
  65         struct counted_string *longest;
  66         int longest_i;
  67
  68         longest = NULL;
  69         longest_i = -1;
  70         for (i = 0; i < r->rewrite_nr; i++) {
  71                 if (!r->rewrite[i])
  72                         continue;
  73                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  74                         if (!prefixcmp(url, r->rewrite[i]->instead_of[j].s) &&
  75                             (!longest ||
  76                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  77                                 longest = &(r->rewrite[i]->instead_of[j]);
  78                                 longest_i = i;
  79                         }
  80                 }
  81         }
  82         if (!longest)
  83                 return url;
  84
  85         ret = xmalloc(r->rewrite[longest_i]->baselen +
  86                      (strlen(url) - longest->len) + 1);
  87         strcpy(ret, r->rewrite[longest_i]->base);
  88         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
  89         return ret;
  90 }
  91
  92 static void add_push_refspec(struct remote *remote, const char *ref)
  93 {
  94         ALLOC_GROW(remote->push_refspec,
  95                    remote->push_refspec_nr + 1,
  96                    remote->push_refspec_alloc);
  97         remote->push_refspec[remote->push_refspec_nr++] = ref;
  98 }
  99
 100 static void add_fetch_refspec(struct remote *remote, const char *ref)
 101 {
 102         ALLOC_GROW(remote->fetch_refspec,
 103                    remote->fetch_refspec_nr + 1,
 104                    remote->fetch_refspec_alloc);
 105         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
 106 }
 107
 108 static void add_url(struct remote *remote, const char *url)
 109 {
 110         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
 111         remote->url[remote->url_nr++] = url;
 112 }
 113
 114 static void add_pushurl(struct remote *remote, const char *pushurl)
 115 {
 116         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
 117         remote->pushurl[remote->pushurl_nr++] = pushurl;
 118 }
 119
 120 static void add_pushurl_alias(struct remote *remote, const char *url)
 121 {
 122         const char *pushurl = alias_url(url, &rewrites_push);
 123         if (pushurl != url)
 124                 add_pushurl(remote, pushurl);
 125 }
 126
 127 static void add_url_alias(struct remote *remote, const char *url)
 128 {
 129         add_url(remote, alias_url(url, &rewrites));
 130         add_pushurl_alias(remote, url);
 131 }
 132
 133 static struct remote *make_remote(const char *name, int len)
 134 {
 135         struct remote *ret;
 136         int i;
 137
 138         for (i = 0; i < remotes_nr; i++) {
 139                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
 140                            !remotes[i]->name[len]) :
 141                     !strcmp(name, remotes[i]->name))
 142                         return remotes[i];
 143         }
 144
 145         ret = xcalloc(1, sizeof(struct remote));
 146         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 147         remotes[remotes_nr++] = ret;
 148         if (len)
 149                 ret->name = xstrndup(name, len);
 150         else
 151                 ret->name = xstrdup(name);
 152         return ret;
 153 }
 154
 155 static void add_merge(struct branch *branch, const char *name)
 156 {
 157         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 158                    branch->merge_alloc);
 159         branch->merge_name[branch->merge_nr++] = name;
 160 }
 161
 162 static struct branch *make_branch(const char *name, int len)
 163 {
 164         struct branch *ret;
 165         int i;
 166         char *refname;
 167
 168         for (i = 0; i < branches_nr; i++) {
 169                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 170                            !branches[i]->name[len]) :
 171                     !strcmp(name, branches[i]->name))
 172                         return branches[i];
 173         }
 174
 175         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 176         ret = xcalloc(1, sizeof(struct branch));
 177         branches[branches_nr++] = ret;
 178         if (len)
 179                 ret->name = xstrndup(name, len);
 180         else
 181                 ret->name = xstrdup(name);
 182         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
 183         strcpy(refname, "refs/heads/");
 184         strcpy(refname + strlen("refs/heads/"), ret->name);
 185         ret->refname = refname;
 186
 187         return ret;
 188 }
 189
 190 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 191 {
 192         struct rewrite *ret;
 193         int i;
 194
 195         for (i = 0; i < r->rewrite_nr; i++) {
 196                 if (len
 197                     ? (len == r->rewrite[i]->baselen &&
 198                        !strncmp(base, r->rewrite[i]->base, len))
 199                     : !strcmp(base, r->rewrite[i]->base))
 200                         return r->rewrite[i];
 201         }
 202
 203         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 204         ret = xcalloc(1, sizeof(struct rewrite));
 205         r->rewrite[r->rewrite_nr++] = ret;
 206         if (len) {
 207                 ret->base = xstrndup(base, len);
 208                 ret->baselen = len;
 209         }
 210         else {
 211                 ret->base = xstrdup(base);
 212                 ret->baselen = strlen(base);
 213         }
 214         return ret;
 215 }
 216
 217 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 218 {
 219         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 220         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 221         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 222         rewrite->instead_of_nr++;
 223 }
 224
 225 static void read_remotes_file(struct remote *remote)
 226 {
 227         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 228
 229         if (!f)
 230                 return;
 231         remote->origin = REMOTE_REMOTES;
 232         while (fgets(buffer, BUF_SIZE, f)) {
 233                 int value_list;
 234                 char *s, *p;
 235
 236                 if (!prefixcmp(buffer, "URL:")) {
 237                         value_list = 0;
 238                         s = buffer + 4;
 239                 } else if (!prefixcmp(buffer, "Push:")) {
 240                         value_list = 1;
 241                         s = buffer + 5;
 242                 } else if (!prefixcmp(buffer, "Pull:")) {
 243                         value_list = 2;
 244                         s = buffer + 5;
 245                 } else
 246                         continue;
 247
 248                 while (isspace(*s))
 249                         s++;
 250                 if (!*s)
 251                         continue;
 252
 253                 p = s + strlen(s);
 254                 while (isspace(p[-1]))
 255                         *--p = 0;
 256
 257                 switch (value_list) {
 258                 case 0:
 259                         add_url_alias(remote, xstrdup(s));
 260                         break;
 261                 case 1:
 262                         add_push_refspec(remote, xstrdup(s));
 263                         break;
 264                 case 2:
 265                         add_fetch_refspec(remote, xstrdup(s));
 266                         break;
 267                 }
 268         }
 269         fclose(f);
 270 }
 271
 272 static void read_branches_file(struct remote *remote)
 273 {
 274         const char *slash = strchr(remote->name, '/');
 275         char *frag;
 276         struct strbuf branch = STRBUF_INIT;
 277         int n = slash ? slash - remote->name : 1000;
 278         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
 279         char *s, *p;
 280         int len;
 281
 282         if (!f)
 283                 return;
 284         s = fgets(buffer, BUF_SIZE, f);
 285         fclose(f);
 286         if (!s)
 287                 return;
 288         while (isspace(*s))
 289                 s++;
 290         if (!*s)
 291                 return;
 292         remote->origin = REMOTE_BRANCHES;
 293         p = s + strlen(s);
 294         while (isspace(p[-1]))
 295                 *--p = 0;
 296         len = p - s;
 297         if (slash)
 298                 len += strlen(slash);
 299         p = xmalloc(len + 1);
 300         strcpy(p, s);
 301         if (slash)
 302                 strcat(p, slash);
 303
 304         /*
 305          * With "slash", e.g. "git fetch jgarzik/netdev-2.6" when
 306          * reading from $GIT_DIR/branches/jgarzik fetches "HEAD" from
 307          * the partial URL obtained from the branches file plus
 308          * "/netdev-2.6" and does not store it in any tracking ref.
 309          * #branch specifier in the file is ignored.
 310          *
 311          * Otherwise, the branches file would have URL and optionally
 312          * #branch specified.  The "master" (or specified) branch is
 313          * fetched and stored in the local branch of the same name.
 314          */
 315         frag = strchr(p, '#');
 316         if (frag) {
 317                 *(frag++) = '\0';
 318                 strbuf_addf(&branch, "refs/heads/%s", frag);
 319         } else
 320                 strbuf_addstr(&branch, "refs/heads/master");
 321         if (!slash) {
 322                 strbuf_addf(&branch, ":refs/heads/%s", remote->name);
 323         } else {
 324                 strbuf_reset(&branch);
 325                 strbuf_addstr(&branch, "HEAD:");
 326         }
 327         add_url_alias(remote, p);
 328         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
 329         /*
 330          * Cogito compatible push: push current HEAD to remote #branch
 331          * (master if missing)
 332          */
 333         strbuf_init(&branch, 0);
 334         strbuf_addstr(&branch, "HEAD");
 335         if (frag)
 336                 strbuf_addf(&branch, ":refs/heads/%s", frag);
 337         else
 338                 strbuf_addstr(&branch, ":refs/heads/master");
 339         add_push_refspec(remote, strbuf_detach(&branch, NULL));
 340         remote->fetch_tags = 1; /* always auto-follow */
 341 }
 342
 343 static int handle_config(const char *key, const char *value, void *cb)
 344 {
 345         const char *name;
 346         const char *subkey;
 347         struct remote *remote;
 348         struct branch *branch;
 349         if (!prefixcmp(key, "branch.")) {
 350                 name = key + 7;
 351                 subkey = strrchr(name, '.');
 352                 if (!subkey)
 353                         return 0;
 354                 branch = make_branch(name, subkey - name);
 355                 if (!strcmp(subkey, ".remote")) {
 356                         if (!value)
 357                                 return config_error_nonbool(key);
 358                         branch->remote_name = xstrdup(value);
 359                         if (branch == current_branch) {
 360                                 default_remote_name = branch->remote_name;
 361                                 explicit_default_remote_name = 1;
 362                         }
 363                 } else if (!strcmp(subkey, ".merge")) {
 364                         if (!value)
 365                                 return config_error_nonbool(key);
 366                         add_merge(branch, xstrdup(value));
 367                 }
 368                 return 0;
 369         }
 370         if (!prefixcmp(key, "url.")) {
 371                 struct rewrite *rewrite;
 372                 name = key + 4;
 373                 subkey = strrchr(name, '.');
 374                 if (!subkey)
 375                         return 0;
 376                 if (!strcmp(subkey, ".insteadof")) {
 377                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 378                         if (!value)
 379                                 return config_error_nonbool(key);
 380                         add_instead_of(rewrite, xstrdup(value));
 381                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 382                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 383                         if (!value)
 384                                 return config_error_nonbool(key);
 385                         add_instead_of(rewrite, xstrdup(value));
 386                 }
 387         }
 388         if (prefixcmp(key,  "remote."))
 389                 return 0;
 390         name = key + 7;
 391         if (*name == '/') {
 392                 warning("Config remote shorthand cannot begin with '/': %s",
 393                         name);
 394                 return 0;
 395         }
 396         subkey = strrchr(name, '.');
 397         if (!subkey)
 398                 return 0;
 399         remote = make_remote(name, subkey - name);
 400         remote->origin = REMOTE_CONFIG;
 401         if (!strcmp(subkey, ".mirror"))
 402                 remote->mirror = git_config_bool(key, value);
 403         else if (!strcmp(subkey, ".skipdefaultupdate"))
 404                 remote->skip_default_update = git_config_bool(key, value);
 405
 406         else if (!strcmp(subkey, ".url")) {
 407                 const char *v;
 408                 if (git_config_string(&v, key, value))
 409                         return -1;
 410                 add_url(remote, v);
 411         } else if (!strcmp(subkey, ".pushurl")) {
 412                 const char *v;
 413                 if (git_config_string(&v, key, value))
 414                         return -1;
 415                 add_pushurl(remote, v);
 416         } else if (!strcmp(subkey, ".push")) {
 417                 const char *v;
 418                 if (git_config_string(&v, key, value))
 419                         return -1;
 420                 add_push_refspec(remote, v);
 421         } else if (!strcmp(subkey, ".fetch")) {
 422                 const char *v;
 423                 if (git_config_string(&v, key, value))
 424                         return -1;
 425                 add_fetch_refspec(remote, v);
 426         } else if (!strcmp(subkey, ".receivepack")) {
 427                 const char *v;
 428                 if (git_config_string(&v, key, value))
 429                         return -1;
 430                 if (!remote->receivepack)
 431                         remote->receivepack = v;
 432                 else
 433                         error("more than one receivepack given, using the first");
 434         } else if (!strcmp(subkey, ".uploadpack")) {
 435                 const char *v;
 436                 if (git_config_string(&v, key, value))
 437                         return -1;
 438                 if (!remote->uploadpack)
 439                         remote->uploadpack = v;
 440                 else
 441                         error("more than one uploadpack given, using the first");
 442         } else if (!strcmp(subkey, ".tagopt")) {
 443                 if (!strcmp(value, "--no-tags"))
 444                         remote->fetch_tags = -1;
 445         } else if (!strcmp(subkey, ".proxy")) {
 446                 return git_config_string((const char **)&remote->http_proxy,
 447                                          key, value);
 448         } else if (!strcmp(subkey, ".vcs")) {
 449                 return git_config_string(&remote->foreign_vcs, key, value);
 450         }
 451         return 0;
 452 }
 453
 454 static void alias_all_urls(void)
 455 {
 456         int i, j;
 457         for (i = 0; i < remotes_nr; i++) {
 458                 int add_pushurl_aliases;
 459                 if (!remotes[i])
 460                         continue;
 461                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 462                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 463                 }
 464                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 465                 for (j = 0; j < remotes[i]->url_nr; j++) {
 466                         if (add_pushurl_aliases)
 467                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 468                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 469                 }
 470         }
 471 }
 472
 473 static void read_config(void)
 474 {
 475         unsigned char sha1[20];
 476         const char *head_ref;
 477         int flag;
 478         if (default_remote_name) // did this already
 479                 return;
 480         default_remote_name = xstrdup("origin");
 481         current_branch = NULL;
 482         head_ref = resolve_ref("HEAD", sha1, 0, &flag);
 483         if (head_ref && (flag & REF_ISSYMREF) &&
 484             !prefixcmp(head_ref, "refs/heads/")) {
 485                 current_branch =
 486                         make_branch(head_ref + strlen("refs/heads/"), 0);
 487         }
 488         git_config(handle_config, NULL);
 489         alias_all_urls();
 490 }
 491
 492 /*
 493  * We need to make sure the tracking branches are well formed, but a
 494  * wildcard refspec in "struct refspec" must have a trailing slash. We
 495  * temporarily drop the trailing '/' while calling check_ref_format(),
 496  * and put it back.  The caller knows that a CHECK_REF_FORMAT_ONELEVEL
 497  * error return is Ok for a wildcard refspec.
 498  */
 499 static int verify_refname(char *name, int is_glob)
 500 {
 501         int result;
 502
 503         result = check_ref_format(name);
 504         if (is_glob && result == CHECK_REF_FORMAT_WILDCARD)
 505                 result = CHECK_REF_FORMAT_OK;
 506         return result;
 507 }
 508
 509 /*
 510  * This function frees a refspec array.
 511  * Warning: code paths should be checked to ensure that the src
 512  *          and dst pointers are always freeable pointers as well
 513  *          as the refspec pointer itself.
 514  */
 515 static void free_refspecs(struct refspec *refspec, int nr_refspec)
 516 {
 517         int i;
 518
 519         if (!refspec)
 520                 return;
 521
 522         for (i = 0; i < nr_refspec; i++) {
 523                 free(refspec[i].src);
 524                 free(refspec[i].dst);
 525         }
 526         free(refspec);
 527 }
 528
 529 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 530 {
 531         int i;
 532         int st;
 533         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 534
 535         for (i = 0; i < nr_refspec; i++) {
 536                 size_t llen;
 537                 int is_glob;
 538                 const char *lhs, *rhs;
 539
 540                 is_glob = 0;
 541
 542                 lhs = refspec[i];
 543                 if (*lhs == '+') {
 544                         rs[i].force = 1;
 545                         lhs++;
 546                 }
 547
 548                 rhs = strrchr(lhs, ':');
 549
 550                 /*
 551                  * Before going on, special case ":" (or "+:") as a refspec
 552                  * for matching refs.
 553                  */
 554                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
 555                         rs[i].matching = 1;
 556                         continue;
 557                 }
 558
 559                 if (rhs) {
 560                         size_t rlen = strlen(++rhs);
 561                         is_glob = (1 <= rlen && strchr(rhs, '*'));
 562                         rs[i].dst = xstrndup(rhs, rlen);
 563                 }
 564
 565                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 566                 if (1 <= llen && memchr(lhs, '*', llen)) {
 567                         if ((rhs && !is_glob) || (!rhs && fetch))
 568                                 goto invalid;
 569                         is_glob = 1;
 570                 } else if (rhs && is_glob) {
 571                         goto invalid;
 572                 }
 573
 574                 rs[i].pattern = is_glob;
 575                 rs[i].src = xstrndup(lhs, llen);
 576
 577                 if (fetch) {
 578                         /*
 579                          * LHS
 580                          * - empty is allowed; it means HEAD.
 581                          * - otherwise it must be a valid looking ref.
 582                          */
 583                         if (!*rs[i].src)
 584                                 ; /* empty is ok */
 585                         else {
 586                                 st = verify_refname(rs[i].src, is_glob);
 587                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 588                                         goto invalid;
 589                         }
 590                         /*
 591                          * RHS
 592                          * - missing is ok, and is same as empty.
 593                          * - empty is ok; it means not to store.
 594                          * - otherwise it must be a valid looking ref.
 595                          */
 596                         if (!rs[i].dst) {
 597                                 ; /* ok */
 598                         } else if (!*rs[i].dst) {
 599                                 ; /* ok */
 600                         } else {
 601                                 st = verify_refname(rs[i].dst, is_glob);
 602                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 603                                         goto invalid;
 604                         }
 605                 } else {
 606                         /*
 607                          * LHS
 608                          * - empty is allowed; it means delete.
 609                          * - when wildcarded, it must be a valid looking ref.
 610                          * - otherwise, it must be an extended SHA-1, but
 611                          *   there is no existing way to validate this.
 612                          */
 613                         if (!*rs[i].src)
 614                                 ; /* empty is ok */
 615                         else if (is_glob) {
 616                                 st = verify_refname(rs[i].src, is_glob);
 617                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 618                                         goto invalid;
 619                         }
 620                         else
 621                                 ; /* anything goes, for now */
 622                         /*
 623                          * RHS
 624                          * - missing is allowed, but LHS then must be a
 625                          *   valid looking ref.
 626                          * - empty is not allowed.
 627                          * - otherwise it must be a valid looking ref.
 628                          */
 629                         if (!rs[i].dst) {
 630                                 st = verify_refname(rs[i].src, is_glob);
 631                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 632                                         goto invalid;
 633                         } else if (!*rs[i].dst) {
 634                                 goto invalid;
 635                         } else {
 636                                 st = verify_refname(rs[i].dst, is_glob);
 637                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 638                                         goto invalid;
 639                         }
 640                 }
 641         }
 642         return rs;
 643
 644  invalid:
 645         if (verify) {
 646                 /*
 647                  * nr_refspec must be greater than zero and i must be valid
 648                  * since it is only possible to reach this point from within
 649                  * the for loop above.
 650                  */
 651                 free_refspecs(rs, i+1);
 652                 return NULL;
 653         }
 654         die("Invalid refspec '%s'", refspec[i]);
 655 }
 656
 657 int valid_fetch_refspec(const char *fetch_refspec_str)
 658 {
 659         const char *fetch_refspec[] = { fetch_refspec_str };
 660         struct refspec *refspec;
 661
 662         refspec = parse_refspec_internal(1, fetch_refspec, 1, 1);
 663         free_refspecs(refspec, 1);
 664         return !!refspec;
 665 }
 666
 667 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 668 {
 669         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 670 }
 671
 672 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 673 {
 674         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 675 }
 676
 677 static int valid_remote_nick(const char *name)
 678 {
 679         if (!name[0] || is_dot_or_dotdot(name))
 680                 return 0;
 681         return !strchr(name, '/'); /* no slash */
 682 }
 683
 684 struct remote *remote_get(const char *name)
 685 {
 686         struct remote *ret;
 687         int name_given = 0;
 688
 689         read_config();
 690         if (name)
 691                 name_given = 1;
 692         else {
 693                 name = default_remote_name;
 694                 name_given = explicit_default_remote_name;
 695         }
 696
 697         ret = make_remote(name, 0);
 698         if (valid_remote_nick(name)) {
 699                 if (!valid_remote(ret))
 700                         read_remotes_file(ret);
 701                 if (!valid_remote(ret))
 702                         read_branches_file(ret);
 703         }
 704         if (name_given && !valid_remote(ret))
 705                 add_url_alias(ret, name);
 706         if (!valid_remote(ret))
 707                 return NULL;
 708         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 709         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 710         return ret;
 711 }
 712
 713 int remote_is_configured(const char *name)
 714 {
 715         int i;
 716         read_config();
 717
 718         for (i = 0; i < remotes_nr; i++)
 719                 if (!strcmp(name, remotes[i]->name))
 720                         return 1;
 721         return 0;
 722 }
 723
 724 int for_each_remote(each_remote_fn fn, void *priv)
 725 {
 726         int i, result = 0;
 727         read_config();
 728         for (i = 0; i < remotes_nr && !result; i++) {
 729                 struct remote *r = remotes[i];
 730                 if (!r)
 731                         continue;
 732                 if (!r->fetch)
 733                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 734                                                        r->fetch_refspec);
 735                 if (!r->push)
 736                         r->push = parse_push_refspec(r->push_refspec_nr,
 737                                                      r->push_refspec);
 738                 result = fn(r, priv);
 739         }
 740         return result;
 741 }
 742
 743 void ref_remove_duplicates(struct ref *ref_map)
 744 {
 745         struct ref **posn;
 746         struct ref *next;
 747         for (; ref_map; ref_map = ref_map->next) {
 748                 if (!ref_map->peer_ref)
 749                         continue;
 750                 posn = &ref_map->next;
 751                 while (*posn) {
 752                         if ((*posn)->peer_ref &&
 753                             !strcmp((*posn)->peer_ref->name,
 754                                     ref_map->peer_ref->name)) {
 755                                 if (strcmp((*posn)->name, ref_map->name))
 756                                         die("%s tracks both %s and %s",
 757                                             ref_map->peer_ref->name,
 758                                             (*posn)->name, ref_map->name);
 759                                 next = (*posn)->next;
 760                                 free((*posn)->peer_ref);
 761                                 free(*posn);
 762                                 *posn = next;
 763                         } else {
 764                                 posn = &(*posn)->next;
 765                         }
 766                 }
 767         }
 768 }
 769
 770 int remote_has_url(struct remote *remote, const char *url)
 771 {
 772         int i;
 773         for (i = 0; i < remote->url_nr; i++) {
 774                 if (!strcmp(remote->url[i], url))
 775                         return 1;
 776         }
 777         return 0;
 778 }
 779
 780 static int match_name_with_pattern(const char *key, const char *name,
 781                                    const char *value, char **result)
 782 {
 783         const char *kstar = strchr(key, '*');
 784         size_t klen;
 785         size_t ksuffixlen;
 786         size_t namelen;
 787         int ret;
 788         if (!kstar)
 789                 die("Key '%s' of pattern had no '*'", key);
 790         klen = kstar - key;
 791         ksuffixlen = strlen(kstar + 1);
 792         namelen = strlen(name);
 793         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 794                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 795         if (ret && value) {
 796                 const char *vstar = strchr(value, '*');
 797                 size_t vlen;
 798                 size_t vsuffixlen;
 799                 if (!vstar)
 800                         die("Value '%s' of pattern has no '*'", value);
 801                 vlen = vstar - value;
 802                 vsuffixlen = strlen(vstar + 1);
 803                 *result = xmalloc(vlen + vsuffixlen +
 804                                   strlen(name) -
 805                                   klen - ksuffixlen + 1);
 806                 strncpy(*result, value, vlen);
 807                 strncpy(*result + vlen,
 808                         name + klen, namelen - klen - ksuffixlen);
 809                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
 810                        vstar + 1);
 811         }
 812         return ret;
 813 }
 814
 815 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 816 {
 817         int find_src = refspec->src == NULL;
 818         char *needle, **result;
 819         int i;
 820
 821         if (find_src) {
 822                 if (!refspec->dst)
 823                         return error("find_tracking: need either src or dst");
 824                 needle = refspec->dst;
 825                 result = &refspec->src;
 826         } else {
 827                 needle = refspec->src;
 828                 result = &refspec->dst;
 829         }
 830
 831         for (i = 0; i < remote->fetch_refspec_nr; i++) {
 832                 struct refspec *fetch = &remote->fetch[i];
 833                 const char *key = find_src ? fetch->dst : fetch->src;
 834                 const char *value = find_src ? fetch->src : fetch->dst;
 835                 if (!fetch->dst)
 836                         continue;
 837                 if (fetch->pattern) {
 838                         if (match_name_with_pattern(key, needle, value, result)) {
 839                                 refspec->force = fetch->force;
 840                                 return 0;
 841                         }
 842                 } else if (!strcmp(needle, key)) {
 843                         *result = xstrdup(value);
 844                         refspec->force = fetch->force;
 845                         return 0;
 846                 }
 847         }
 848         return -1;
 849 }
 850
 851 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 852                 const char *name)
 853 {
 854         size_t len = strlen(name);
 855         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 856         memcpy(ref->name, prefix, prefixlen);
 857         memcpy(ref->name + prefixlen, name, len);
 858         return ref;
 859 }
 860
 861 struct ref *alloc_ref(const char *name)
 862 {
 863         return alloc_ref_with_prefix("", 0, name);
 864 }
 865
 866 static struct ref *copy_ref(const struct ref *ref)
 867 {
 868         struct ref *cpy;
 869         size_t len;
 870         if (!ref)
 871                 return NULL;
 872         len = strlen(ref->name);
 873         cpy = xmalloc(sizeof(struct ref) + len + 1);
 874         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 875         cpy->next = NULL;
 876         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 877         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 878         cpy->peer_ref = copy_ref(ref->peer_ref);
 879         return cpy;
 880 }
 881
 882 struct ref *copy_ref_list(const struct ref *ref)
 883 {
 884         struct ref *ret = NULL;
 885         struct ref **tail = &ret;
 886         while (ref) {
 887                 *tail = copy_ref(ref);
 888                 ref = ref->next;
 889                 tail = &((*tail)->next);
 890         }
 891         return ret;
 892 }
 893
 894 static void free_ref(struct ref *ref)
 895 {
 896         if (!ref)
 897                 return;
 898         free_ref(ref->peer_ref);
 899         free(ref->remote_status);
 900         free(ref->symref);
 901         free(ref);
 902 }
 903
 904 void free_refs(struct ref *ref)
 905 {
 906         struct ref *next;
 907         while (ref) {
 908                 next = ref->next;
 909                 free_ref(ref);
 910                 ref = next;
 911         }
 912 }
 913
 914 static int count_refspec_match(const char *pattern,
 915                                struct ref *refs,
 916                                struct ref **matched_ref)
 917 {
 918         int patlen = strlen(pattern);
 919         struct ref *matched_weak = NULL;
 920         struct ref *matched = NULL;
 921         int weak_match = 0;
 922         int match = 0;
 923
 924         for (weak_match = match = 0; refs; refs = refs->next) {
 925                 char *name = refs->name;
 926                 int namelen = strlen(name);
 927
 928                 if (!refname_match(pattern, name, ref_rev_parse_rules))
 929                         continue;
 930
 931                 /* A match is "weak" if it is with refs outside
 932                  * heads or tags, and did not specify the pattern
 933                  * in full (e.g. "refs/remotes/origin/master") or at
 934                  * least from the toplevel (e.g. "remotes/origin/master");
 935                  * otherwise "git push $URL master" would result in
 936                  * ambiguity between remotes/origin/master and heads/master
 937                  * at the remote site.
 938                  */
 939                 if (namelen != patlen &&
 940                     patlen != namelen - 5 &&
 941                     prefixcmp(name, "refs/heads/") &&
 942                     prefixcmp(name, "refs/tags/")) {
 943                         /* We want to catch the case where only weak
 944                          * matches are found and there are multiple
 945                          * matches, and where more than one strong
 946                          * matches are found, as ambiguous.  One
 947                          * strong match with zero or more weak matches
 948                          * are acceptable as a unique match.
 949                          */
 950                         matched_weak = refs;
 951                         weak_match++;
 952                 }
 953                 else {
 954                         matched = refs;
 955                         match++;
 956                 }
 957         }
 958         if (!matched) {
 959                 *matched_ref = matched_weak;
 960                 return weak_match;
 961         }
 962         else {
 963                 *matched_ref = matched;
 964                 return match;
 965         }
 966 }
 967
 968 static void tail_link_ref(struct ref *ref, struct ref ***tail)
 969 {
 970         **tail = ref;
 971         while (ref->next)
 972                 ref = ref->next;
 973         *tail = &ref->next;
 974 }
 975
 976 static struct ref *try_explicit_object_name(const char *name)
 977 {
 978         unsigned char sha1[20];
 979         struct ref *ref;
 980
 981         if (!*name) {
 982                 ref = alloc_ref("(delete)");
 983                 hashclr(ref->new_sha1);
 984                 return ref;
 985         }
 986         if (get_sha1(name, sha1))
 987                 return NULL;
 988         ref = alloc_ref(name);
 989         hashcpy(ref->new_sha1, sha1);
 990         return ref;
 991 }
 992
 993 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
 994 {
 995         struct ref *ret = alloc_ref(name);
 996         tail_link_ref(ret, tail);
 997         return ret;
 998 }
 999
1000 static char *guess_ref(const char *name, struct ref *peer)
1001 {
1002         struct strbuf buf = STRBUF_INIT;
1003         unsigned char sha1[20];
1004
1005         const char *r = resolve_ref(peer->name, sha1, 1, NULL);
1006         if (!r)
1007                 return NULL;
1008
1009         if (!prefixcmp(r, "refs/heads/"))
1010                 strbuf_addstr(&buf, "refs/heads/");
1011         else if (!prefixcmp(r, "refs/tags/"))
1012                 strbuf_addstr(&buf, "refs/tags/");
1013         else
1014                 return NULL;
1015
1016         strbuf_addstr(&buf, name);
1017         return strbuf_detach(&buf, NULL);
1018 }
1019
1020 static int match_explicit(struct ref *src, struct ref *dst,
1021                           struct ref ***dst_tail,
1022                           struct refspec *rs)
1023 {
1024         struct ref *matched_src, *matched_dst;
1025         int copy_src;
1026
1027         const char *dst_value = rs->dst;
1028         char *dst_guess;
1029
1030         if (rs->pattern || rs->matching)
1031                 return 0;
1032
1033         matched_src = matched_dst = NULL;
1034         switch (count_refspec_match(rs->src, src, &matched_src)) {
1035         case 1:
1036                 copy_src = 1;
1037                 break;
1038         case 0:
1039                 /* The source could be in the get_sha1() format
1040                  * not a reference name.  :refs/other is a
1041                  * way to delete 'other' ref at the remote end.
1042                  */
1043                 matched_src = try_explicit_object_name(rs->src);
1044                 if (!matched_src)
1045                         return error("src refspec %s does not match any.", rs->src);
1046                 copy_src = 0;
1047                 break;
1048         default:
1049                 return error("src refspec %s matches more than one.", rs->src);
1050         }
1051
1052         if (!dst_value) {
1053                 unsigned char sha1[20];
1054                 int flag;
1055
1056                 dst_value = resolve_ref(matched_src->name, sha1, 1, &flag);
1057                 if (!dst_value ||
1058                     ((flag & REF_ISSYMREF) &&
1059                      prefixcmp(dst_value, "refs/heads/")))
1060                         die("%s cannot be resolved to branch.",
1061                             matched_src->name);
1062         }
1063
1064         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1065         case 1:
1066                 break;
1067         case 0:
1068                 if (!memcmp(dst_value, "refs/", 5))
1069                         matched_dst = make_linked_ref(dst_value, dst_tail);
1070                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1071                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1072                 else
1073                         error("unable to push to unqualified destination: %s\n"
1074                               "The destination refspec neither matches an "
1075                               "existing ref on the remote nor\n"
1076                               "begins with refs/, and we are unable to "
1077                               "guess a prefix based on the source ref.",
1078                               dst_value);
1079                 break;
1080         default:
1081                 matched_dst = NULL;
1082                 error("dst refspec %s matches more than one.",
1083                       dst_value);
1084                 break;
1085         }
1086         if (!matched_dst)
1087                 return -1;
1088         if (matched_dst->peer_ref)
1089                 return error("dst ref %s receives from more than one src.",
1090                       matched_dst->name);
1091         else {
1092                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1093                 matched_dst->force = rs->force;
1094         }
1095         return 0;
1096 }
1097
1098 static int match_explicit_refs(struct ref *src, struct ref *dst,
1099                                struct ref ***dst_tail, struct refspec *rs,
1100                                int rs_nr)
1101 {
1102         int i, errs;
1103         for (i = errs = 0; i < rs_nr; i++)
1104                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1105         return errs;
1106 }
1107
1108 static const struct refspec *check_pattern_match(const struct refspec *rs,
1109                                                  int rs_nr,
1110                                                  const struct ref *src)
1111 {
1112         int i;
1113         int matching_refs = -1;
1114         for (i = 0; i < rs_nr; i++) {
1115                 if (rs[i].matching &&
1116                     (matching_refs == -1 || rs[i].force)) {
1117                         matching_refs = i;
1118                         continue;
1119                 }
1120
1121                 if (rs[i].pattern && match_name_with_pattern(rs[i].src, src->name,
1122                                                              NULL, NULL))
1123                         return rs + i;
1124         }
1125         if (matching_refs != -1)
1126                 return rs + matching_refs;
1127         else
1128                 return NULL;
1129 }
1130
1131 static struct ref **tail_ref(struct ref **head)
1132 {
1133         struct ref **tail = head;
1134         while (*tail)
1135                 tail = &((*tail)->next);
1136         return tail;
1137 }
1138
1139 /*
1140  * Note. This is used only by "push"; refspec matching rules for
1141  * push and fetch are subtly different, so do not try to reuse it
1142  * without thinking.
1143  */
1144 int match_refs(struct ref *src, struct ref **dst,
1145                int nr_refspec, const char **refspec, int flags)
1146 {
1147         struct refspec *rs;
1148         int send_all = flags & MATCH_REFS_ALL;
1149         int send_mirror = flags & MATCH_REFS_MIRROR;
1150         int errs;
1151         static const char *default_refspec[] = { ":", NULL };
1152         struct ref **dst_tail = tail_ref(dst);
1153
1154         if (!nr_refspec) {
1155                 nr_refspec = 1;
1156                 refspec = default_refspec;
1157         }
1158         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1159         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1160
1161         /* pick the remainder */
1162         for ( ; src; src = src->next) {
1163                 struct ref *dst_peer;
1164                 const struct refspec *pat = NULL;
1165                 char *dst_name;
1166                 if (src->peer_ref)
1167                         continue;
1168
1169                 pat = check_pattern_match(rs, nr_refspec, src);
1170                 if (!pat)
1171                         continue;
1172
1173                 if (pat->matching) {
1174                         /*
1175                          * "matching refs"; traditionally we pushed everything
1176                          * including refs outside refs/heads/ hierarchy, but
1177                          * that does not make much sense these days.
1178                          */
1179                         if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
1180                                 continue;
1181                         dst_name = xstrdup(src->name);
1182
1183                 } else {
1184                         const char *dst_side = pat->dst ? pat->dst : pat->src;
1185                         if (!match_name_with_pattern(pat->src, src->name,
1186                                                      dst_side, &dst_name))
1187                                 die("Didn't think it matches any more");
1188                 }
1189                 dst_peer = find_ref_by_name(*dst, dst_name);
1190                 if (dst_peer) {
1191                         if (dst_peer->peer_ref)
1192                                 /* We're already sending something to this ref. */
1193                                 goto free_name;
1194
1195                 } else {
1196                         if (pat->matching && !(send_all || send_mirror))
1197                                 /*
1198                                  * Remote doesn't have it, and we have no
1199                                  * explicit pattern, and we don't have
1200                                  * --all nor --mirror.
1201                                  */
1202                                 goto free_name;
1203
1204                         /* Create a new one and link it */
1205                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1206                         hashcpy(dst_peer->new_sha1, src->new_sha1);
1207                 }
1208                 dst_peer->peer_ref = copy_ref(src);
1209                 dst_peer->force = pat->force;
1210         free_name:
1211                 free(dst_name);
1212         }
1213         if (errs)
1214                 return -1;
1215         return 0;
1216 }
1217
1218 struct branch *branch_get(const char *name)
1219 {
1220         struct branch *ret;
1221
1222         read_config();
1223         if (!name || !*name || !strcmp(name, "HEAD"))
1224                 ret = current_branch;
1225         else
1226                 ret = make_branch(name, 0);
1227         if (ret && ret->remote_name) {
1228                 ret->remote = remote_get(ret->remote_name);
1229                 if (ret->merge_nr) {
1230                         int i;
1231                         ret->merge = xcalloc(sizeof(*ret->merge),
1232                                              ret->merge_nr);
1233                         for (i = 0; i < ret->merge_nr; i++) {
1234                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1235                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1236                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1237                                     && !strcmp(ret->remote_name, "."))
1238                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1239                         }
1240                 }
1241         }
1242         return ret;
1243 }
1244
1245 int branch_has_merge_config(struct branch *branch)
1246 {
1247         return branch && !!branch->merge;
1248 }
1249
1250 int branch_merge_matches(struct branch *branch,
1251                                  int i,
1252                                  const char *refname)
1253 {
1254         if (!branch || i < 0 || i >= branch->merge_nr)
1255                 return 0;
1256         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1257 }
1258
1259 static struct ref *get_expanded_map(const struct ref *remote_refs,
1260                                     const struct refspec *refspec)
1261 {
1262         const struct ref *ref;
1263         struct ref *ret = NULL;
1264         struct ref **tail = &ret;
1265
1266         char *expn_name;
1267
1268         for (ref = remote_refs; ref; ref = ref->next) {
1269                 if (strchr(ref->name, '^'))
1270                         continue; /* a dereference item */
1271                 if (match_name_with_pattern(refspec->src, ref->name,
1272                                             refspec->dst, &expn_name)) {
1273                         struct ref *cpy = copy_ref(ref);
1274
1275                         cpy->peer_ref = alloc_ref(expn_name);
1276                         free(expn_name);
1277                         if (refspec->force)
1278                                 cpy->peer_ref->force = 1;
1279                         *tail = cpy;
1280                         tail = &cpy->next;
1281                 }
1282         }
1283
1284         return ret;
1285 }
1286
1287 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1288 {
1289         const struct ref *ref;
1290         for (ref = refs; ref; ref = ref->next) {
1291                 if (refname_match(name, ref->name, ref_fetch_rules))
1292                         return ref;
1293         }
1294         return NULL;
1295 }
1296
1297 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1298 {
1299         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1300
1301         if (!ref)
1302                 return NULL;
1303
1304         return copy_ref(ref);
1305 }
1306
1307 static struct ref *get_local_ref(const char *name)
1308 {
1309         if (!name || name[0] == '\0')
1310                 return NULL;
1311
1312         if (!prefixcmp(name, "refs/"))
1313                 return alloc_ref(name);
1314
1315         if (!prefixcmp(name, "heads/") ||
1316             !prefixcmp(name, "tags/") ||
1317             !prefixcmp(name, "remotes/"))
1318                 return alloc_ref_with_prefix("refs/", 5, name);
1319
1320         return alloc_ref_with_prefix("refs/heads/", 11, name);
1321 }
1322
1323 int get_fetch_map(const struct ref *remote_refs,
1324                   const struct refspec *refspec,
1325                   struct ref ***tail,
1326                   int missing_ok)
1327 {
1328         struct ref *ref_map, **rmp;
1329
1330         if (refspec->pattern) {
1331                 ref_map = get_expanded_map(remote_refs, refspec);
1332         } else {
1333                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1334
1335                 ref_map = get_remote_ref(remote_refs, name);
1336                 if (!missing_ok && !ref_map)
1337                         die("Couldn't find remote ref %s", name);
1338                 if (ref_map) {
1339                         ref_map->peer_ref = get_local_ref(refspec->dst);
1340                         if (ref_map->peer_ref && refspec->force)
1341                                 ref_map->peer_ref->force = 1;
1342                 }
1343         }
1344
1345         for (rmp = &ref_map; *rmp; ) {
1346                 if ((*rmp)->peer_ref) {
1347                         int st = check_ref_format((*rmp)->peer_ref->name + 5);
1348                         if (st && st != CHECK_REF_FORMAT_ONELEVEL) {
1349                                 struct ref *ignore = *rmp;
1350                                 error("* Ignoring funny ref '%s' locally",
1351                                       (*rmp)->peer_ref->name);
1352                                 *rmp = (*rmp)->next;
1353                                 free(ignore->peer_ref);
1354                                 free(ignore);
1355                                 continue;
1356                         }
1357                 }
1358                 rmp = &((*rmp)->next);
1359         }
1360
1361         if (ref_map)
1362                 tail_link_ref(ref_map, tail);
1363
1364         return 0;
1365 }
1366
1367 int resolve_remote_symref(struct ref *ref, struct ref *list)
1368 {
1369         if (!ref->symref)
1370                 return 0;
1371         for (; list; list = list->next)
1372                 if (!strcmp(ref->symref, list->name)) {
1373                         hashcpy(ref->old_sha1, list->old_sha1);
1374                         return 0;
1375                 }
1376         return 1;
1377 }
1378
1379 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1380 {
1381         while (list) {
1382                 struct commit_list *temp = list;
1383                 temp->item->object.flags &= ~mark;
1384                 list = temp->next;
1385                 free(temp);
1386         }
1387 }
1388
1389 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1390 {
1391         struct object *o;
1392         struct commit *old, *new;
1393         struct commit_list *list, *used;
1394         int found = 0;
1395
1396         /* Both new and old must be commit-ish and new is descendant of
1397          * old.  Otherwise we require --force.
1398          */
1399         o = deref_tag(parse_object(old_sha1), NULL, 0);
1400         if (!o || o->type != OBJ_COMMIT)
1401                 return 0;
1402         old = (struct commit *) o;
1403
1404         o = deref_tag(parse_object(new_sha1), NULL, 0);
1405         if (!o || o->type != OBJ_COMMIT)
1406                 return 0;
1407         new = (struct commit *) o;
1408
1409         if (parse_commit(new) < 0)
1410                 return 0;
1411
1412         used = list = NULL;
1413         commit_list_insert(new, &list);
1414         while (list) {
1415                 new = pop_most_recent_commit(&list, TMP_MARK);
1416                 commit_list_insert(new, &used);
1417                 if (new == old) {
1418                         found = 1;
1419                         break;
1420                 }
1421         }
1422         unmark_and_free(list, TMP_MARK);
1423         unmark_and_free(used, TMP_MARK);
1424         return found;
1425 }
1426
1427 /*
1428  * Return true if there is anything to report, otherwise false.
1429  */
1430 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1431 {
1432         unsigned char sha1[20];
1433         struct commit *ours, *theirs;
1434         char symmetric[84];
1435         struct rev_info revs;
1436         const char *rev_argv[10], *base;
1437         int rev_argc;
1438
1439         /*
1440          * Nothing to report unless we are marked to build on top of
1441          * somebody else.
1442          */
1443         if (!branch ||
1444             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1445                 return 0;
1446
1447         /*
1448          * If what we used to build on no longer exists, there is
1449          * nothing to report.
1450          */
1451         base = branch->merge[0]->dst;
1452         if (!resolve_ref(base, sha1, 1, NULL))
1453                 return 0;
1454         theirs = lookup_commit_reference(sha1);
1455         if (!theirs)
1456                 return 0;
1457
1458         if (!resolve_ref(branch->refname, sha1, 1, NULL))
1459                 return 0;
1460         ours = lookup_commit_reference(sha1);
1461         if (!ours)
1462                 return 0;
1463
1464         /* are we the same? */
1465         if (theirs == ours)
1466                 return 0;
1467
1468         /* Run "rev-list --left-right ours...theirs" internally... */
1469         rev_argc = 0;
1470         rev_argv[rev_argc++] = NULL;
1471         rev_argv[rev_argc++] = "--left-right";
1472         rev_argv[rev_argc++] = symmetric;
1473         rev_argv[rev_argc++] = "--";
1474         rev_argv[rev_argc] = NULL;
1475
1476         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1477         strcpy(symmetric + 40, "...");
1478         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1479
1480         init_revisions(&revs, NULL);
1481         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1482         prepare_revision_walk(&revs);
1483
1484         /* ... and count the commits on each side. */
1485         *num_ours = 0;
1486         *num_theirs = 0;
1487         while (1) {
1488                 struct commit *c = get_revision(&revs);
1489                 if (!c)
1490                         break;
1491                 if (c->object.flags & SYMMETRIC_LEFT)
1492                         (*num_ours)++;
1493                 else
1494                         (*num_theirs)++;
1495         }
1496
1497         /* clear object flags smudged by the above traversal */
1498         clear_commit_marks(ours, ALL_REV_FLAGS);
1499         clear_commit_marks(theirs, ALL_REV_FLAGS);
1500         return 1;
1501 }
1502
1503 /*
1504  * Return true when there is anything to report, otherwise false.
1505  */
1506 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1507 {
1508         int num_ours, num_theirs;
1509         const char *base;
1510
1511         if (!stat_tracking_info(branch, &num_ours, &num_theirs))
1512                 return 0;
1513
1514         base = branch->merge[0]->dst;
1515         base = shorten_unambiguous_ref(base, 0);
1516         if (!num_theirs)
1517                 strbuf_addf(sb, "Your branch is ahead of '%s' "
1518                             "by %d commit%s.\n",
1519                             base, num_ours, (num_ours == 1) ? "" : "s");
1520         else if (!num_ours)
1521                 strbuf_addf(sb, "Your branch is behind '%s' "
1522                             "by %d commit%s, "
1523                             "and can be fast-forwarded.\n",
1524                             base, num_theirs, (num_theirs == 1) ? "" : "s");
1525         else
1526                 strbuf_addf(sb, "Your branch and '%s' have diverged,\n"
1527                             "and have %d and %d different commit(s) each, "
1528                             "respectively.\n",
1529                             base, num_ours, num_theirs);
1530         return 1;
1531 }
1532
1533 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1534 {
1535         struct ref ***local_tail = cb_data;
1536         struct ref *ref;
1537         int len;
1538
1539         /* we already know it starts with refs/ to get here */
1540         if (check_ref_format(refname + 5))
1541                 return 0;
1542
1543         len = strlen(refname) + 1;
1544         ref = xcalloc(1, sizeof(*ref) + len);
1545         hashcpy(ref->new_sha1, sha1);
1546         memcpy(ref->name, refname, len);
1547         **local_tail = ref;
1548         *local_tail = &ref->next;
1549         return 0;
1550 }
1551
1552 struct ref *get_local_heads(void)
1553 {
1554         struct ref *local_refs = NULL, **local_tail = &local_refs;
1555         for_each_ref(one_local_ref, &local_tail);
1556         return local_refs;
1557 }
1558
1559 struct ref *guess_remote_head(const struct ref *head,
1560                               const struct ref *refs,
1561                               int all)
1562 {
1563         const struct ref *r;
1564         struct ref *list = NULL;
1565         struct ref **tail = &list;
1566
1567         if (!head)
1568                 return NULL;
1569
1570         /*
1571          * Some transports support directly peeking at
1572          * where HEAD points; if that is the case, then
1573          * we don't have to guess.
1574          */
1575         if (head->symref)
1576                 return copy_ref(find_ref_by_name(refs, head->symref));
1577
1578         /* If refs/heads/master could be right, it is. */
1579         if (!all) {
1580                 r = find_ref_by_name(refs, "refs/heads/master");
1581                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1582                         return copy_ref(r);
1583         }
1584
1585         /* Look for another ref that points there */
1586         for (r = refs; r; r = r->next) {
1587                 if (r != head && !hashcmp(r->old_sha1, head->old_sha1)) {
1588                         *tail = copy_ref(r);
1589                         tail = &((*tail)->next);
1590                         if (!all)
1591                                 break;
1592                 }
1593         }
1594
1595         return list;
1596 }