git.oblomov.eu Git - git/blob - remote.c

   1 #include "cache.h"
   2 #include "remote.h"
   3 #include "refs.h"
   4 #include "commit.h"
   5 #include "diff.h"
   6 #include "revision.h"
   7 #include "dir.h"
   8 #include "tag.h"
   9
  10 static struct refspec s_tag_refspec = {
  11         0,
  12         1,
  13         0,
  14         "refs/tags/*",
  15         "refs/tags/*"
  16 };
  17
  18 const struct refspec *tag_refspec = &s_tag_refspec;
  19
  20 struct counted_string {
  21         size_t len;
  22         const char *s;
  23 };
  24 struct rewrite {
  25         const char *base;
  26         size_t baselen;
  27         struct counted_string *instead_of;
  28         int instead_of_nr;
  29         int instead_of_alloc;
  30 };
  31 struct rewrites {
  32         struct rewrite **rewrite;
  33         int rewrite_alloc;
  34         int rewrite_nr;
  35 };
  36
  37 static struct remote **remotes;
  38 static int remotes_alloc;
  39 static int remotes_nr;
  40
  41 static struct branch **branches;
  42 static int branches_alloc;
  43 static int branches_nr;
  44
  45 static struct branch *current_branch;
  46 static const char *default_remote_name;
  47 static int explicit_default_remote_name;
  48
  49 static struct rewrites rewrites;
  50 static struct rewrites rewrites_push;
  51
  52 #define BUF_SIZE (2048)
  53 static char buffer[BUF_SIZE];
  54
  55 static int valid_remote(const struct remote *remote)
  56 {
  57         return !!remote->url;
  58 }
  59
  60 static const char *alias_url(const char *url, struct rewrites *r)
  61 {
  62         int i, j;
  63         char *ret;
  64         struct counted_string *longest;
  65         int longest_i;
  66
  67         longest = NULL;
  68         longest_i = -1;
  69         for (i = 0; i < r->rewrite_nr; i++) {
  70                 if (!r->rewrite[i])
  71                         continue;
  72                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  73                         if (!prefixcmp(url, r->rewrite[i]->instead_of[j].s) &&
  74                             (!longest ||
  75                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  76                                 longest = &(r->rewrite[i]->instead_of[j]);
  77                                 longest_i = i;
  78                         }
  79                 }
  80         }
  81         if (!longest)
  82                 return url;
  83
  84         ret = xmalloc(r->rewrite[longest_i]->baselen +
  85                      (strlen(url) - longest->len) + 1);
  86         strcpy(ret, r->rewrite[longest_i]->base);
  87         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
  88         return ret;
  89 }
  90
  91 static void add_push_refspec(struct remote *remote, const char *ref)
  92 {
  93         ALLOC_GROW(remote->push_refspec,
  94                    remote->push_refspec_nr + 1,
  95                    remote->push_refspec_alloc);
  96         remote->push_refspec[remote->push_refspec_nr++] = ref;
  97 }
  98
  99 static void add_fetch_refspec(struct remote *remote, const char *ref)
 100 {
 101         ALLOC_GROW(remote->fetch_refspec,
 102                    remote->fetch_refspec_nr + 1,
 103                    remote->fetch_refspec_alloc);
 104         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
 105 }
 106
 107 static void add_url(struct remote *remote, const char *url)
 108 {
 109         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
 110         remote->url[remote->url_nr++] = url;
 111 }
 112
 113 static void add_pushurl(struct remote *remote, const char *pushurl)
 114 {
 115         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
 116         remote->pushurl[remote->pushurl_nr++] = pushurl;
 117 }
 118
 119 static void add_pushurl_alias(struct remote *remote, const char *url)
 120 {
 121         const char *pushurl = alias_url(url, &rewrites_push);
 122         if (pushurl != url)
 123                 add_pushurl(remote, pushurl);
 124 }
 125
 126 static void add_url_alias(struct remote *remote, const char *url)
 127 {
 128         add_url(remote, alias_url(url, &rewrites));
 129         add_pushurl_alias(remote, url);
 130 }
 131
 132 static struct remote *make_remote(const char *name, int len)
 133 {
 134         struct remote *ret;
 135         int i;
 136
 137         for (i = 0; i < remotes_nr; i++) {
 138                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
 139                            !remotes[i]->name[len]) :
 140                     !strcmp(name, remotes[i]->name))
 141                         return remotes[i];
 142         }
 143
 144         ret = xcalloc(1, sizeof(struct remote));
 145         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 146         remotes[remotes_nr++] = ret;
 147         if (len)
 148                 ret->name = xstrndup(name, len);
 149         else
 150                 ret->name = xstrdup(name);
 151         return ret;
 152 }
 153
 154 static void add_merge(struct branch *branch, const char *name)
 155 {
 156         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 157                    branch->merge_alloc);
 158         branch->merge_name[branch->merge_nr++] = name;
 159 }
 160
 161 static struct branch *make_branch(const char *name, int len)
 162 {
 163         struct branch *ret;
 164         int i;
 165         char *refname;
 166
 167         for (i = 0; i < branches_nr; i++) {
 168                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 169                            !branches[i]->name[len]) :
 170                     !strcmp(name, branches[i]->name))
 171                         return branches[i];
 172         }
 173
 174         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 175         ret = xcalloc(1, sizeof(struct branch));
 176         branches[branches_nr++] = ret;
 177         if (len)
 178                 ret->name = xstrndup(name, len);
 179         else
 180                 ret->name = xstrdup(name);
 181         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
 182         strcpy(refname, "refs/heads/");
 183         strcpy(refname + strlen("refs/heads/"), ret->name);
 184         ret->refname = refname;
 185
 186         return ret;
 187 }
 188
 189 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 190 {
 191         struct rewrite *ret;
 192         int i;
 193
 194         for (i = 0; i < r->rewrite_nr; i++) {
 195                 if (len
 196                     ? (len == r->rewrite[i]->baselen &&
 197                        !strncmp(base, r->rewrite[i]->base, len))
 198                     : !strcmp(base, r->rewrite[i]->base))
 199                         return r->rewrite[i];
 200         }
 201
 202         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 203         ret = xcalloc(1, sizeof(struct rewrite));
 204         r->rewrite[r->rewrite_nr++] = ret;
 205         if (len) {
 206                 ret->base = xstrndup(base, len);
 207                 ret->baselen = len;
 208         }
 209         else {
 210                 ret->base = xstrdup(base);
 211                 ret->baselen = strlen(base);
 212         }
 213         return ret;
 214 }
 215
 216 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 217 {
 218         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 219         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 220         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 221         rewrite->instead_of_nr++;
 222 }
 223
 224 static void read_remotes_file(struct remote *remote)
 225 {
 226         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 227
 228         if (!f)
 229                 return;
 230         remote->origin = REMOTE_REMOTES;
 231         while (fgets(buffer, BUF_SIZE, f)) {
 232                 int value_list;
 233                 char *s, *p;
 234
 235                 if (!prefixcmp(buffer, "URL:")) {
 236                         value_list = 0;
 237                         s = buffer + 4;
 238                 } else if (!prefixcmp(buffer, "Push:")) {
 239                         value_list = 1;
 240                         s = buffer + 5;
 241                 } else if (!prefixcmp(buffer, "Pull:")) {
 242                         value_list = 2;
 243                         s = buffer + 5;
 244                 } else
 245                         continue;
 246
 247                 while (isspace(*s))
 248                         s++;
 249                 if (!*s)
 250                         continue;
 251
 252                 p = s + strlen(s);
 253                 while (isspace(p[-1]))
 254                         *--p = 0;
 255
 256                 switch (value_list) {
 257                 case 0:
 258                         add_url_alias(remote, xstrdup(s));
 259                         break;
 260                 case 1:
 261                         add_push_refspec(remote, xstrdup(s));
 262                         break;
 263                 case 2:
 264                         add_fetch_refspec(remote, xstrdup(s));
 265                         break;
 266                 }
 267         }
 268         fclose(f);
 269 }
 270
 271 static void read_branches_file(struct remote *remote)
 272 {
 273         const char *slash = strchr(remote->name, '/');
 274         char *frag;
 275         struct strbuf branch = STRBUF_INIT;
 276         int n = slash ? slash - remote->name : 1000;
 277         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
 278         char *s, *p;
 279         int len;
 280
 281         if (!f)
 282                 return;
 283         s = fgets(buffer, BUF_SIZE, f);
 284         fclose(f);
 285         if (!s)
 286                 return;
 287         while (isspace(*s))
 288                 s++;
 289         if (!*s)
 290                 return;
 291         remote->origin = REMOTE_BRANCHES;
 292         p = s + strlen(s);
 293         while (isspace(p[-1]))
 294                 *--p = 0;
 295         len = p - s;
 296         if (slash)
 297                 len += strlen(slash);
 298         p = xmalloc(len + 1);
 299         strcpy(p, s);
 300         if (slash)
 301                 strcat(p, slash);
 302
 303         /*
 304          * With "slash", e.g. "git fetch jgarzik/netdev-2.6" when
 305          * reading from $GIT_DIR/branches/jgarzik fetches "HEAD" from
 306          * the partial URL obtained from the branches file plus
 307          * "/netdev-2.6" and does not store it in any tracking ref.
 308          * #branch specifier in the file is ignored.
 309          *
 310          * Otherwise, the branches file would have URL and optionally
 311          * #branch specified.  The "master" (or specified) branch is
 312          * fetched and stored in the local branch of the same name.
 313          */
 314         frag = strchr(p, '#');
 315         if (frag) {
 316                 *(frag++) = '\0';
 317                 strbuf_addf(&branch, "refs/heads/%s", frag);
 318         } else
 319                 strbuf_addstr(&branch, "refs/heads/master");
 320         if (!slash) {
 321                 strbuf_addf(&branch, ":refs/heads/%s", remote->name);
 322         } else {
 323                 strbuf_reset(&branch);
 324                 strbuf_addstr(&branch, "HEAD:");
 325         }
 326         add_url_alias(remote, p);
 327         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
 328         /*
 329          * Cogito compatible push: push current HEAD to remote #branch
 330          * (master if missing)
 331          */
 332         strbuf_init(&branch, 0);
 333         strbuf_addstr(&branch, "HEAD");
 334         if (frag)
 335                 strbuf_addf(&branch, ":refs/heads/%s", frag);
 336         else
 337                 strbuf_addstr(&branch, ":refs/heads/master");
 338         add_push_refspec(remote, strbuf_detach(&branch, NULL));
 339         remote->fetch_tags = 1; /* always auto-follow */
 340 }
 341
 342 static int handle_config(const char *key, const char *value, void *cb)
 343 {
 344         const char *name;
 345         const char *subkey;
 346         struct remote *remote;
 347         struct branch *branch;
 348         if (!prefixcmp(key, "branch.")) {
 349                 name = key + 7;
 350                 subkey = strrchr(name, '.');
 351                 if (!subkey)
 352                         return 0;
 353                 branch = make_branch(name, subkey - name);
 354                 if (!strcmp(subkey, ".remote")) {
 355                         if (!value)
 356                                 return config_error_nonbool(key);
 357                         branch->remote_name = xstrdup(value);
 358                         if (branch == current_branch) {
 359                                 default_remote_name = branch->remote_name;
 360                                 explicit_default_remote_name = 1;
 361                         }
 362                 } else if (!strcmp(subkey, ".merge")) {
 363                         if (!value)
 364                                 return config_error_nonbool(key);
 365                         add_merge(branch, xstrdup(value));
 366                 }
 367                 return 0;
 368         }
 369         if (!prefixcmp(key, "url.")) {
 370                 struct rewrite *rewrite;
 371                 name = key + 4;
 372                 subkey = strrchr(name, '.');
 373                 if (!subkey)
 374                         return 0;
 375                 if (!strcmp(subkey, ".insteadof")) {
 376                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 377                         if (!value)
 378                                 return config_error_nonbool(key);
 379                         add_instead_of(rewrite, xstrdup(value));
 380                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 381                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 382                         if (!value)
 383                                 return config_error_nonbool(key);
 384                         add_instead_of(rewrite, xstrdup(value));
 385                 }
 386         }
 387         if (prefixcmp(key,  "remote."))
 388                 return 0;
 389         name = key + 7;
 390         if (*name == '/') {
 391                 warning("Config remote shorthand cannot begin with '/': %s",
 392                         name);
 393                 return 0;
 394         }
 395         subkey = strrchr(name, '.');
 396         if (!subkey)
 397                 return 0;
 398         remote = make_remote(name, subkey - name);
 399         remote->origin = REMOTE_CONFIG;
 400         if (!strcmp(subkey, ".mirror"))
 401                 remote->mirror = git_config_bool(key, value);
 402         else if (!strcmp(subkey, ".skipdefaultupdate"))
 403                 remote->skip_default_update = git_config_bool(key, value);
 404
 405         else if (!strcmp(subkey, ".url")) {
 406                 const char *v;
 407                 if (git_config_string(&v, key, value))
 408                         return -1;
 409                 add_url(remote, v);
 410         } else if (!strcmp(subkey, ".pushurl")) {
 411                 const char *v;
 412                 if (git_config_string(&v, key, value))
 413                         return -1;
 414                 add_pushurl(remote, v);
 415         } else if (!strcmp(subkey, ".push")) {
 416                 const char *v;
 417                 if (git_config_string(&v, key, value))
 418                         return -1;
 419                 add_push_refspec(remote, v);
 420         } else if (!strcmp(subkey, ".fetch")) {
 421                 const char *v;
 422                 if (git_config_string(&v, key, value))
 423                         return -1;
 424                 add_fetch_refspec(remote, v);
 425         } else if (!strcmp(subkey, ".receivepack")) {
 426                 const char *v;
 427                 if (git_config_string(&v, key, value))
 428                         return -1;
 429                 if (!remote->receivepack)
 430                         remote->receivepack = v;
 431                 else
 432                         error("more than one receivepack given, using the first");
 433         } else if (!strcmp(subkey, ".uploadpack")) {
 434                 const char *v;
 435                 if (git_config_string(&v, key, value))
 436                         return -1;
 437                 if (!remote->uploadpack)
 438                         remote->uploadpack = v;
 439                 else
 440                         error("more than one uploadpack given, using the first");
 441         } else if (!strcmp(subkey, ".tagopt")) {
 442                 if (!strcmp(value, "--no-tags"))
 443                         remote->fetch_tags = -1;
 444         } else if (!strcmp(subkey, ".proxy")) {
 445                 return git_config_string((const char **)&remote->http_proxy,
 446                                          key, value);
 447         }
 448         return 0;
 449 }
 450
 451 static void alias_all_urls(void)
 452 {
 453         int i, j;
 454         for (i = 0; i < remotes_nr; i++) {
 455                 int add_pushurl_aliases;
 456                 if (!remotes[i])
 457                         continue;
 458                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 459                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 460                 }
 461                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 462                 for (j = 0; j < remotes[i]->url_nr; j++) {
 463                         if (add_pushurl_aliases)
 464                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 465                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 466                 }
 467         }
 468 }
 469
 470 static void read_config(void)
 471 {
 472         unsigned char sha1[20];
 473         const char *head_ref;
 474         int flag;
 475         if (default_remote_name) // did this already
 476                 return;
 477         default_remote_name = xstrdup("origin");
 478         current_branch = NULL;
 479         head_ref = resolve_ref("HEAD", sha1, 0, &flag);
 480         if (head_ref && (flag & REF_ISSYMREF) &&
 481             !prefixcmp(head_ref, "refs/heads/")) {
 482                 current_branch =
 483                         make_branch(head_ref + strlen("refs/heads/"), 0);
 484         }
 485         git_config(handle_config, NULL);
 486         alias_all_urls();
 487 }
 488
 489 /*
 490  * We need to make sure the tracking branches are well formed, but a
 491  * wildcard refspec in "struct refspec" must have a trailing slash. We
 492  * temporarily drop the trailing '/' while calling check_ref_format(),
 493  * and put it back.  The caller knows that a CHECK_REF_FORMAT_ONELEVEL
 494  * error return is Ok for a wildcard refspec.
 495  */
 496 static int verify_refname(char *name, int is_glob)
 497 {
 498         int result;
 499
 500         result = check_ref_format(name);
 501         if (is_glob && result == CHECK_REF_FORMAT_WILDCARD)
 502                 result = CHECK_REF_FORMAT_OK;
 503         return result;
 504 }
 505
 506 /*
 507  * This function frees a refspec array.
 508  * Warning: code paths should be checked to ensure that the src
 509  *          and dst pointers are always freeable pointers as well
 510  *          as the refspec pointer itself.
 511  */
 512 static void free_refspecs(struct refspec *refspec, int nr_refspec)
 513 {
 514         int i;
 515
 516         if (!refspec)
 517                 return;
 518
 519         for (i = 0; i < nr_refspec; i++) {
 520                 free(refspec[i].src);
 521                 free(refspec[i].dst);
 522         }
 523         free(refspec);
 524 }
 525
 526 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 527 {
 528         int i;
 529         int st;
 530         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 531
 532         for (i = 0; i < nr_refspec; i++) {
 533                 size_t llen;
 534                 int is_glob;
 535                 const char *lhs, *rhs;
 536
 537                 is_glob = 0;
 538
 539                 lhs = refspec[i];
 540                 if (*lhs == '+') {
 541                         rs[i].force = 1;
 542                         lhs++;
 543                 }
 544
 545                 rhs = strrchr(lhs, ':');
 546
 547                 /*
 548                  * Before going on, special case ":" (or "+:") as a refspec
 549                  * for matching refs.
 550                  */
 551                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
 552                         rs[i].matching = 1;
 553                         continue;
 554                 }
 555
 556                 if (rhs) {
 557                         size_t rlen = strlen(++rhs);
 558                         is_glob = (1 <= rlen && strchr(rhs, '*'));
 559                         rs[i].dst = xstrndup(rhs, rlen);
 560                 }
 561
 562                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 563                 if (1 <= llen && memchr(lhs, '*', llen)) {
 564                         if ((rhs && !is_glob) || (!rhs && fetch))
 565                                 goto invalid;
 566                         is_glob = 1;
 567                 } else if (rhs && is_glob) {
 568                         goto invalid;
 569                 }
 570
 571                 rs[i].pattern = is_glob;
 572                 rs[i].src = xstrndup(lhs, llen);
 573
 574                 if (fetch) {
 575                         /*
 576                          * LHS
 577                          * - empty is allowed; it means HEAD.
 578                          * - otherwise it must be a valid looking ref.
 579                          */
 580                         if (!*rs[i].src)
 581                                 ; /* empty is ok */
 582                         else {
 583                                 st = verify_refname(rs[i].src, is_glob);
 584                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 585                                         goto invalid;
 586                         }
 587                         /*
 588                          * RHS
 589                          * - missing is ok, and is same as empty.
 590                          * - empty is ok; it means not to store.
 591                          * - otherwise it must be a valid looking ref.
 592                          */
 593                         if (!rs[i].dst) {
 594                                 ; /* ok */
 595                         } else if (!*rs[i].dst) {
 596                                 ; /* ok */
 597                         } else {
 598                                 st = verify_refname(rs[i].dst, is_glob);
 599                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 600                                         goto invalid;
 601                         }
 602                 } else {
 603                         /*
 604                          * LHS
 605                          * - empty is allowed; it means delete.
 606                          * - when wildcarded, it must be a valid looking ref.
 607                          * - otherwise, it must be an extended SHA-1, but
 608                          *   there is no existing way to validate this.
 609                          */
 610                         if (!*rs[i].src)
 611                                 ; /* empty is ok */
 612                         else if (is_glob) {
 613                                 st = verify_refname(rs[i].src, is_glob);
 614                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 615                                         goto invalid;
 616                         }
 617                         else
 618                                 ; /* anything goes, for now */
 619                         /*
 620                          * RHS
 621                          * - missing is allowed, but LHS then must be a
 622                          *   valid looking ref.
 623                          * - empty is not allowed.
 624                          * - otherwise it must be a valid looking ref.
 625                          */
 626                         if (!rs[i].dst) {
 627                                 st = verify_refname(rs[i].src, is_glob);
 628                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 629                                         goto invalid;
 630                         } else if (!*rs[i].dst) {
 631                                 goto invalid;
 632                         } else {
 633                                 st = verify_refname(rs[i].dst, is_glob);
 634                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 635                                         goto invalid;
 636                         }
 637                 }
 638         }
 639         return rs;
 640
 641  invalid:
 642         if (verify) {
 643                 /*
 644                  * nr_refspec must be greater than zero and i must be valid
 645                  * since it is only possible to reach this point from within
 646                  * the for loop above.
 647                  */
 648                 free_refspecs(rs, i+1);
 649                 return NULL;
 650         }
 651         die("Invalid refspec '%s'", refspec[i]);
 652 }
 653
 654 int valid_fetch_refspec(const char *fetch_refspec_str)
 655 {
 656         const char *fetch_refspec[] = { fetch_refspec_str };
 657         struct refspec *refspec;
 658
 659         refspec = parse_refspec_internal(1, fetch_refspec, 1, 1);
 660         free_refspecs(refspec, 1);
 661         return !!refspec;
 662 }
 663
 664 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 665 {
 666         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 667 }
 668
 669 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 670 {
 671         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 672 }
 673
 674 static int valid_remote_nick(const char *name)
 675 {
 676         if (!name[0] || is_dot_or_dotdot(name))
 677                 return 0;
 678         return !strchr(name, '/'); /* no slash */
 679 }
 680
 681 struct remote *remote_get(const char *name)
 682 {
 683         struct remote *ret;
 684         int name_given = 0;
 685
 686         read_config();
 687         if (name)
 688                 name_given = 1;
 689         else {
 690                 name = default_remote_name;
 691                 name_given = explicit_default_remote_name;
 692         }
 693
 694         ret = make_remote(name, 0);
 695         if (valid_remote_nick(name)) {
 696                 if (!valid_remote(ret))
 697                         read_remotes_file(ret);
 698                 if (!valid_remote(ret))
 699                         read_branches_file(ret);
 700         }
 701         if (name_given && !valid_remote(ret))
 702                 add_url_alias(ret, name);
 703         if (!valid_remote(ret))
 704                 return NULL;
 705         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 706         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 707         return ret;
 708 }
 709
 710 int remote_is_configured(const char *name)
 711 {
 712         int i;
 713         read_config();
 714
 715         for (i = 0; i < remotes_nr; i++)
 716                 if (!strcmp(name, remotes[i]->name))
 717                         return 1;
 718         return 0;
 719 }
 720
 721 int for_each_remote(each_remote_fn fn, void *priv)
 722 {
 723         int i, result = 0;
 724         read_config();
 725         for (i = 0; i < remotes_nr && !result; i++) {
 726                 struct remote *r = remotes[i];
 727                 if (!r)
 728                         continue;
 729                 if (!r->fetch)
 730                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 731                                                        r->fetch_refspec);
 732                 if (!r->push)
 733                         r->push = parse_push_refspec(r->push_refspec_nr,
 734                                                      r->push_refspec);
 735                 result = fn(r, priv);
 736         }
 737         return result;
 738 }
 739
 740 void ref_remove_duplicates(struct ref *ref_map)
 741 {
 742         struct ref **posn;
 743         struct ref *next;
 744         for (; ref_map; ref_map = ref_map->next) {
 745                 if (!ref_map->peer_ref)
 746                         continue;
 747                 posn = &ref_map->next;
 748                 while (*posn) {
 749                         if ((*posn)->peer_ref &&
 750                             !strcmp((*posn)->peer_ref->name,
 751                                     ref_map->peer_ref->name)) {
 752                                 if (strcmp((*posn)->name, ref_map->name))
 753                                         die("%s tracks both %s and %s",
 754                                             ref_map->peer_ref->name,
 755                                             (*posn)->name, ref_map->name);
 756                                 next = (*posn)->next;
 757                                 free((*posn)->peer_ref);
 758                                 free(*posn);
 759                                 *posn = next;
 760                         } else {
 761                                 posn = &(*posn)->next;
 762                         }
 763                 }
 764         }
 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 }