remote.c

   1 #include "cache.h"
   2 #include "remote.h"
   3 #include "refs.h"
   4 #include "commit.h"
   5 #include "diff.h"
   6 #include "revision.h"
   7 #include "dir.h"
   8 #include "tag.h"
   9
  10 static struct refspec s_tag_refspec = {
  11         0,
  12         1,
  13         0,
  14         "refs/tags/*",
  15         "refs/tags/*"
  16 };
  17
  18 const struct refspec *tag_refspec = &s_tag_refspec;
  19
  20 struct counted_string {
  21         size_t len;
  22         const char *s;
  23 };
  24 struct rewrite {
  25         const char *base;
  26         size_t baselen;
  27         struct counted_string *instead_of;
  28         int instead_of_nr;
  29         int instead_of_alloc;
  30 };
  31 struct rewrites {
  32         struct rewrite **rewrite;
  33         int rewrite_alloc;
  34         int rewrite_nr;
  35 };
  36
  37 static struct remote **remotes;
  38 static int remotes_alloc;
  39 static int remotes_nr;
  40
  41 static struct branch **branches;
  42 static int branches_alloc;
  43 static int branches_nr;
  44
  45 static struct branch *current_branch;
  46 static const char *default_remote_name;
  47 static int explicit_default_remote_name;
  48
  49 static struct rewrites rewrites;
  50 static struct rewrites rewrites_push;
  51
  52 #define BUF_SIZE (2048)
  53 static char buffer[BUF_SIZE];
  54
  55 static const char *alias_url(const char *url, struct rewrites *r)
  56 {
  57         int i, j;
  58         char *ret;
  59         struct counted_string *longest;
  60         int longest_i;
  61
  62         longest = NULL;
  63         longest_i = -1;
  64         for (i = 0; i < r->rewrite_nr; i++) {
  65                 if (!r->rewrite[i])
  66                         continue;
  67                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  68                         if (!prefixcmp(url, r->rewrite[i]->instead_of[j].s) &&
  69                             (!longest ||
  70                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  71                                 longest = &(r->rewrite[i]->instead_of[j]);
  72                                 longest_i = i;
  73                         }
  74                 }
  75         }
  76         if (!longest)
  77                 return url;
  78
  79         ret = xmalloc(r->rewrite[longest_i]->baselen +
  80                      (strlen(url) - longest->len) + 1);
  81         strcpy(ret, r->rewrite[longest_i]->base);
  82         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
  83         return ret;
  84 }
  85
  86 static void add_push_refspec(struct remote *remote, const char *ref)
  87 {
  88         ALLOC_GROW(remote->push_refspec,
  89                    remote->push_refspec_nr + 1,
  90                    remote->push_refspec_alloc);
  91         remote->push_refspec[remote->push_refspec_nr++] = ref;
  92 }
  93
  94 static void add_fetch_refspec(struct remote *remote, const char *ref)
  95 {
  96         ALLOC_GROW(remote->fetch_refspec,
  97                    remote->fetch_refspec_nr + 1,
  98                    remote->fetch_refspec_alloc);
  99         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
 100 }
 101
 102 static void add_url(struct remote *remote, const char *url)
 103 {
 104         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
 105         remote->url[remote->url_nr++] = url;
 106 }
 107
 108 static void add_pushurl(struct remote *remote, const char *pushurl)
 109 {
 110         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
 111         remote->pushurl[remote->pushurl_nr++] = pushurl;
 112 }
 113
 114 static void add_pushurl_alias(struct remote *remote, const char *url)
 115 {
 116         const char *pushurl = alias_url(url, &rewrites_push);
 117         if (pushurl != url)
 118                 add_pushurl(remote, pushurl);
 119 }
 120
 121 static void add_url_alias(struct remote *remote, const char *url)
 122 {
 123         add_url(remote, alias_url(url, &rewrites));
 124         add_pushurl_alias(remote, url);
 125 }
 126
 127 static struct remote *make_remote(const char *name, int len)
 128 {
 129         struct remote *ret;
 130         int i;
 131
 132         for (i = 0; i < remotes_nr; i++) {
 133                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
 134                            !remotes[i]->name[len]) :
 135                     !strcmp(name, remotes[i]->name))
 136                         return remotes[i];
 137         }
 138
 139         ret = xcalloc(1, sizeof(struct remote));
 140         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 141         remotes[remotes_nr++] = ret;
 142         if (len)
 143                 ret->name = xstrndup(name, len);
 144         else
 145                 ret->name = xstrdup(name);
 146         return ret;
 147 }
 148
 149 static void add_merge(struct branch *branch, const char *name)
 150 {
 151         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 152                    branch->merge_alloc);
 153         branch->merge_name[branch->merge_nr++] = name;
 154 }
 155
 156 static struct branch *make_branch(const char *name, int len)
 157 {
 158         struct branch *ret;
 159         int i;
 160         char *refname;
 161
 162         for (i = 0; i < branches_nr; i++) {
 163                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 164                            !branches[i]->name[len]) :
 165                     !strcmp(name, branches[i]->name))
 166                         return branches[i];
 167         }
 168
 169         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 170         ret = xcalloc(1, sizeof(struct branch));
 171         branches[branches_nr++] = ret;
 172         if (len)
 173                 ret->name = xstrndup(name, len);
 174         else
 175                 ret->name = xstrdup(name);
 176         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
 177         strcpy(refname, "refs/heads/");
 178         strcpy(refname + strlen("refs/heads/"), ret->name);
 179         ret->refname = refname;
 180
 181         return ret;
 182 }
 183
 184 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 185 {
 186         struct rewrite *ret;
 187         int i;
 188
 189         for (i = 0; i < r->rewrite_nr; i++) {
 190                 if (len
 191                     ? (len == r->rewrite[i]->baselen &&
 192                        !strncmp(base, r->rewrite[i]->base, len))
 193                     : !strcmp(base, r->rewrite[i]->base))
 194                         return r->rewrite[i];
 195         }
 196
 197         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 198         ret = xcalloc(1, sizeof(struct rewrite));
 199         r->rewrite[r->rewrite_nr++] = ret;
 200         if (len) {
 201                 ret->base = xstrndup(base, len);
 202                 ret->baselen = len;
 203         }
 204         else {
 205                 ret->base = xstrdup(base);
 206                 ret->baselen = strlen(base);
 207         }
 208         return ret;
 209 }
 210
 211 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 212 {
 213         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 214         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 215         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 216         rewrite->instead_of_nr++;
 217 }
 218
 219 static void read_remotes_file(struct remote *remote)
 220 {
 221         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 222
 223         if (!f)
 224                 return;
 225         remote->origin = REMOTE_REMOTES;
 226         while (fgets(buffer, BUF_SIZE, f)) {
 227                 int value_list;
 228                 char *s, *p;
 229
 230                 if (!prefixcmp(buffer, "URL:")) {
 231                         value_list = 0;
 232                         s = buffer + 4;
 233                 } else if (!prefixcmp(buffer, "Push:")) {
 234                         value_list = 1;
 235                         s = buffer + 5;
 236                 } else if (!prefixcmp(buffer, "Pull:")) {
 237                         value_list = 2;
 238                         s = buffer + 5;
 239                 } else
 240                         continue;
 241
 242                 while (isspace(*s))
 243                         s++;
 244                 if (!*s)
 245                         continue;
 246
 247                 p = s + strlen(s);
 248                 while (isspace(p[-1]))
 249                         *--p = 0;
 250
 251                 switch (value_list) {
 252                 case 0:
 253                         add_url_alias(remote, xstrdup(s));
 254                         break;
 255                 case 1:
 256                         add_push_refspec(remote, xstrdup(s));
 257                         break;
 258                 case 2:
 259                         add_fetch_refspec(remote, xstrdup(s));
 260                         break;
 261                 }
 262         }
 263         fclose(f);
 264 }
 265
 266 static void read_branches_file(struct remote *remote)
 267 {
 268         const char *slash = strchr(remote->name, '/');
 269         char *frag;
 270         struct strbuf branch = STRBUF_INIT;
 271         int n = slash ? slash - remote->name : 1000;
 272         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
 273         char *s, *p;
 274         int len;
 275
 276         if (!f)
 277                 return;
 278         s = fgets(buffer, BUF_SIZE, f);
 279         fclose(f);
 280         if (!s)
 281                 return;
 282         while (isspace(*s))
 283                 s++;
 284         if (!*s)
 285                 return;
 286         remote->origin = REMOTE_BRANCHES;
 287         p = s + strlen(s);
 288         while (isspace(p[-1]))
 289                 *--p = 0;
 290         len = p - s;
 291         if (slash)
 292                 len += strlen(slash);
 293         p = xmalloc(len + 1);
 294         strcpy(p, s);
 295         if (slash)
 296                 strcat(p, slash);
 297
 298         /*
 299          * With "slash", e.g. "git fetch jgarzik/netdev-2.6" when
 300          * reading from $GIT_DIR/branches/jgarzik fetches "HEAD" from
 301          * the partial URL obtained from the branches file plus
 302          * "/netdev-2.6" and does not store it in any tracking ref.
 303          * #branch specifier in the file is ignored.
 304          *
 305          * Otherwise, the branches file would have URL and optionally
 306          * #branch specified.  The "master" (or specified) branch is
 307          * fetched and stored in the local branch of the same name.
 308          */
 309         frag = strchr(p, '#');
 310         if (frag) {
 311                 *(frag++) = '\0';
 312                 strbuf_addf(&branch, "refs/heads/%s", frag);
 313         } else
 314                 strbuf_addstr(&branch, "refs/heads/master");
 315         if (!slash) {
 316                 strbuf_addf(&branch, ":refs/heads/%s", remote->name);
 317         } else {
 318                 strbuf_reset(&branch);
 319                 strbuf_addstr(&branch, "HEAD:");
 320         }
 321         add_url_alias(remote, p);
 322         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
 323         /*
 324          * Cogito compatible push: push current HEAD to remote #branch
 325          * (master if missing)
 326          */
 327         strbuf_init(&branch, 0);
 328         strbuf_addstr(&branch, "HEAD");
 329         if (frag)
 330                 strbuf_addf(&branch, ":refs/heads/%s", frag);
 331         else
 332                 strbuf_addstr(&branch, ":refs/heads/master");
 333         add_push_refspec(remote, strbuf_detach(&branch, NULL));
 334         remote->fetch_tags = 1; /* always auto-follow */
 335 }
 336
 337 static int handle_config(const char *key, const char *value, void *cb)
 338 {
 339         const char *name;
 340         const char *subkey;
 341         struct remote *remote;
 342         struct branch *branch;
 343         if (!prefixcmp(key, "branch.")) {
 344                 name = key + 7;
 345                 subkey = strrchr(name, '.');
 346                 if (!subkey)
 347                         return 0;
 348                 branch = make_branch(name, subkey - name);
 349                 if (!strcmp(subkey, ".remote")) {
 350                         if (!value)
 351                                 return config_error_nonbool(key);
 352                         branch->remote_name = xstrdup(value);
 353                         if (branch == current_branch) {
 354                                 default_remote_name = branch->remote_name;
 355                                 explicit_default_remote_name = 1;
 356                         }
 357                 } else if (!strcmp(subkey, ".merge")) {
 358                         if (!value)
 359                                 return config_error_nonbool(key);
 360                         add_merge(branch, xstrdup(value));
 361                 }
 362                 return 0;
 363         }
 364         if (!prefixcmp(key, "url.")) {
 365                 struct rewrite *rewrite;
 366                 name = key + 4;
 367                 subkey = strrchr(name, '.');
 368                 if (!subkey)
 369                         return 0;
 370                 if (!strcmp(subkey, ".insteadof")) {
 371                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 372                         if (!value)
 373                                 return config_error_nonbool(key);
 374                         add_instead_of(rewrite, xstrdup(value));
 375                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 376                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 377                         if (!value)
 378                                 return config_error_nonbool(key);
 379                         add_instead_of(rewrite, xstrdup(value));
 380                 }
 381         }
 382         if (prefixcmp(key,  "remote."))
 383                 return 0;
 384         name = key + 7;
 385         if (*name == '/') {
 386                 warning("Config remote shorthand cannot begin with '/': %s",
 387                         name);
 388                 return 0;
 389         }
 390         subkey = strrchr(name, '.');
 391         if (!subkey)
 392                 return 0;
 393         remote = make_remote(name, subkey - name);
 394         remote->origin = REMOTE_CONFIG;
 395         if (!strcmp(subkey, ".mirror"))
 396                 remote->mirror = git_config_bool(key, value);
 397         else if (!strcmp(subkey, ".skipdefaultupdate"))
 398                 remote->skip_default_update = git_config_bool(key, value);
 399
 400         else if (!strcmp(subkey, ".url")) {
 401                 const char *v;
 402                 if (git_config_string(&v, key, value))
 403                         return -1;
 404                 add_url(remote, v);
 405         } else if (!strcmp(subkey, ".pushurl")) {
 406                 const char *v;
 407                 if (git_config_string(&v, key, value))
 408                         return -1;
 409                 add_pushurl(remote, v);
 410         } else if (!strcmp(subkey, ".push")) {
 411                 const char *v;
 412                 if (git_config_string(&v, key, value))
 413                         return -1;
 414                 add_push_refspec(remote, v);
 415         } else if (!strcmp(subkey, ".fetch")) {
 416                 const char *v;
 417                 if (git_config_string(&v, key, value))
 418                         return -1;
 419                 add_fetch_refspec(remote, v);
 420         } else if (!strcmp(subkey, ".receivepack")) {
 421                 const char *v;
 422                 if (git_config_string(&v, key, value))
 423                         return -1;
 424                 if (!remote->receivepack)
 425                         remote->receivepack = v;
 426                 else
 427                         error("more than one receivepack given, using the first");
 428         } else if (!strcmp(subkey, ".uploadpack")) {
 429                 const char *v;
 430                 if (git_config_string(&v, key, value))
 431                         return -1;
 432                 if (!remote->uploadpack)
 433                         remote->uploadpack = v;
 434                 else
 435                         error("more than one uploadpack given, using the first");
 436         } else if (!strcmp(subkey, ".tagopt")) {
 437                 if (!strcmp(value, "--no-tags"))
 438                         remote->fetch_tags = -1;
 439         } else if (!strcmp(subkey, ".proxy")) {
 440                 return git_config_string((const char **)&remote->http_proxy,
 441                                          key, value);
 442         }
 443         return 0;
 444 }
 445
 446 static void alias_all_urls(void)
 447 {
 448         int i, j;
 449         for (i = 0; i < remotes_nr; i++) {
 450                 int add_pushurl_aliases;
 451                 if (!remotes[i])
 452                         continue;
 453                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 454                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 455                 }
 456                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 457                 for (j = 0; j < remotes[i]->url_nr; j++) {
 458                         if (add_pushurl_aliases)
 459                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 460                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 461                 }
 462         }
 463 }
 464
 465 static void read_config(void)
 466 {
 467         unsigned char sha1[20];
 468         const char *head_ref;
 469         int flag;
 470         if (default_remote_name) // did this already
 471                 return;
 472         default_remote_name = xstrdup("origin");
 473         current_branch = NULL;
 474         head_ref = resolve_ref("HEAD", sha1, 0, &flag);
 475         if (head_ref && (flag & REF_ISSYMREF) &&
 476             !prefixcmp(head_ref, "refs/heads/")) {
 477                 current_branch =
 478                         make_branch(head_ref + strlen("refs/heads/"), 0);
 479         }
 480         git_config(handle_config, NULL);
 481         alias_all_urls();
 482 }
 483
 484 /*
 485  * We need to make sure the tracking branches are well formed, but a
 486  * wildcard refspec in "struct refspec" must have a trailing slash. We
 487  * temporarily drop the trailing '/' while calling check_ref_format(),
 488  * and put it back.  The caller knows that a CHECK_REF_FORMAT_ONELEVEL
 489  * error return is Ok for a wildcard refspec.
 490  */
 491 static int verify_refname(char *name, int is_glob)
 492 {
 493         int result;
 494
 495         result = check_ref_format(name);
 496         if (is_glob && result == CHECK_REF_FORMAT_WILDCARD)
 497                 result = CHECK_REF_FORMAT_OK;
 498         return result;
 499 }
 500
 501 /*
 502  * This function frees a refspec array.
 503  * Warning: code paths should be checked to ensure that the src
 504  *          and dst pointers are always freeable pointers as well
 505  *          as the refspec pointer itself.
 506  */
 507 static void free_refspecs(struct refspec *refspec, int nr_refspec)
 508 {
 509         int i;
 510
 511         if (!refspec)
 512                 return;
 513
 514         for (i = 0; i < nr_refspec; i++) {
 515                 free(refspec[i].src);
 516                 free(refspec[i].dst);
 517         }
 518         free(refspec);
 519 }
 520
 521 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 522 {
 523         int i;
 524         int st;
 525         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 526
 527         for (i = 0; i < nr_refspec; i++) {
 528                 size_t llen;
 529                 int is_glob;
 530                 const char *lhs, *rhs;
 531
 532                 is_glob = 0;
 533
 534                 lhs = refspec[i];
 535                 if (*lhs == '+') {
 536                         rs[i].force = 1;
 537                         lhs++;
 538                 }
 539
 540                 rhs = strrchr(lhs, ':');
 541
 542                 /*
 543                  * Before going on, special case ":" (or "+:") as a refspec
 544                  * for matching refs.
 545                  */
 546                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
 547                         rs[i].matching = 1;
 548                         continue;
 549                 }
 550
 551                 if (rhs) {
 552                         size_t rlen = strlen(++rhs);
 553                         is_glob = (1 <= rlen && strchr(rhs, '*'));
 554                         rs[i].dst = xstrndup(rhs, rlen);
 555                 }
 556
 557                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 558                 if (1 <= llen && memchr(lhs, '*', llen)) {
 559                         if ((rhs && !is_glob) || (!rhs && fetch))
 560                                 goto invalid;
 561                         is_glob = 1;
 562                 } else if (rhs && is_glob) {
 563                         goto invalid;
 564                 }
 565
 566                 rs[i].pattern = is_glob;
 567                 rs[i].src = xstrndup(lhs, llen);
 568
 569                 if (fetch) {
 570                         /*
 571                          * LHS
 572                          * - empty is allowed; it means HEAD.
 573                          * - otherwise it must be a valid looking ref.
 574                          */
 575                         if (!*rs[i].src)
 576                                 ; /* empty is ok */
 577                         else {
 578                                 st = verify_refname(rs[i].src, is_glob);
 579                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 580                                         goto invalid;
 581                         }
 582                         /*
 583                          * RHS
 584                          * - missing is ok, and is same as empty.
 585                          * - empty is ok; it means not to store.
 586                          * - otherwise it must be a valid looking ref.
 587                          */
 588                         if (!rs[i].dst) {
 589                                 ; /* ok */
 590                         } else if (!*rs[i].dst) {
 591                                 ; /* ok */
 592                         } else {
 593                                 st = verify_refname(rs[i].dst, is_glob);
 594                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 595                                         goto invalid;
 596                         }
 597                 } else {
 598                         /*
 599                          * LHS
 600                          * - empty is allowed; it means delete.
 601                          * - when wildcarded, it must be a valid looking ref.
 602                          * - otherwise, it must be an extended SHA-1, but
 603                          *   there is no existing way to validate this.
 604                          */
 605                         if (!*rs[i].src)
 606                                 ; /* empty is ok */
 607                         else if (is_glob) {
 608                                 st = verify_refname(rs[i].src, is_glob);
 609                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 610                                         goto invalid;
 611                         }
 612                         else
 613                                 ; /* anything goes, for now */
 614                         /*
 615                          * RHS
 616                          * - missing is allowed, but LHS then must be a
 617                          *   valid looking ref.
 618                          * - empty is not allowed.
 619                          * - otherwise it must be a valid looking ref.
 620                          */
 621                         if (!rs[i].dst) {
 622                                 st = verify_refname(rs[i].src, is_glob);
 623                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 624                                         goto invalid;
 625                         } else if (!*rs[i].dst) {
 626                                 goto invalid;
 627                         } else {
 628                                 st = verify_refname(rs[i].dst, is_glob);
 629                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 630                                         goto invalid;
 631                         }
 632                 }
 633         }
 634         return rs;
 635
 636  invalid:
 637         if (verify) {
 638                 /*
 639                  * nr_refspec must be greater than zero and i must be valid
 640                  * since it is only possible to reach this point from within
 641                  * the for loop above.
 642                  */
 643                 free_refspecs(rs, i+1);
 644                 return NULL;
 645         }
 646         die("Invalid refspec '%s'", refspec[i]);
 647 }
 648
 649 int valid_fetch_refspec(const char *fetch_refspec_str)
 650 {
 651         const char *fetch_refspec[] = { fetch_refspec_str };
 652         struct refspec *refspec;
 653
 654         refspec = parse_refspec_internal(1, fetch_refspec, 1, 1);
 655         free_refspecs(refspec, 1);
 656         return !!refspec;
 657 }
 658
 659 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 660 {
 661         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 662 }
 663
 664 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 665 {
 666         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 667 }
 668
 669 static int valid_remote_nick(const char *name)
 670 {
 671         if (!name[0] || is_dot_or_dotdot(name))
 672                 return 0;
 673         return !strchr(name, '/'); /* no slash */
 674 }
 675
 676 struct remote *remote_get(const char *name)
 677 {
 678         struct remote *ret;
 679         int name_given = 0;
 680
 681         read_config();
 682         if (name)
 683                 name_given = 1;
 684         else {
 685                 name = default_remote_name;
 686                 name_given = explicit_default_remote_name;
 687         }
 688
 689         ret = make_remote(name, 0);
 690         if (valid_remote_nick(name)) {
 691                 if (!ret->url)
 692                         read_remotes_file(ret);
 693                 if (!ret->url)
 694                         read_branches_file(ret);
 695         }
 696         if (name_given && !ret->url)
 697                 add_url_alias(ret, name);
 698         if (!ret->url)
 699                 return NULL;
 700         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 701         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 702         return ret;
 703 }
 704
 705 int remote_is_configured(const char *name)
 706 {
 707         int i;
 708         read_config();
 709
 710         for (i = 0; i < remotes_nr; i++)
 711                 if (!strcmp(name, remotes[i]->name))
 712                         return 1;
 713         return 0;
 714 }
 715
 716 int for_each_remote(each_remote_fn fn, void *priv)
 717 {
 718         int i, result = 0;
 719         read_config();
 720         for (i = 0; i < remotes_nr && !result; i++) {
 721                 struct remote *r = remotes[i];
 722                 if (!r)
 723                         continue;
 724                 if (!r->fetch)
 725                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 726                                                        r->fetch_refspec);
 727                 if (!r->push)
 728                         r->push = parse_push_refspec(r->push_refspec_nr,
 729                                                      r->push_refspec);
 730                 result = fn(r, priv);
 731         }
 732         return result;
 733 }
 734
 735 void ref_remove_duplicates(struct ref *ref_map)
 736 {
 737         struct ref **posn;
 738         struct ref *next;
 739         for (; ref_map; ref_map = ref_map->next) {
 740                 if (!ref_map->peer_ref)
 741                         continue;
 742                 posn = &ref_map->next;
 743                 while (*posn) {
 744                         if ((*posn)->peer_ref &&
 745                             !strcmp((*posn)->peer_ref->name,
 746                                     ref_map->peer_ref->name)) {
 747                                 if (strcmp((*posn)->name, ref_map->name))
 748                                         die("%s tracks both %s and %s",
 749                                             ref_map->peer_ref->name,
 750                                             (*posn)->name, ref_map->name);
 751                                 next = (*posn)->next;
 752                                 free((*posn)->peer_ref);
 753                                 free(*posn);
 754                                 *posn = next;
 755                         } else {
 756                                 posn = &(*posn)->next;
 757                         }
 758                 }
 759         }
 760 }
 761
 762 int remote_has_url(struct remote *remote, const char *url)
 763 {
 764         int i;
 765         for (i = 0; i < remote->url_nr; i++) {
 766                 if (!strcmp(remote->url[i], url))
 767                         return 1;
 768         }
 769         return 0;
 770 }
 771
 772 static int match_name_with_pattern(const char *key, const char *name,
 773                                    const char *value, char **result)
 774 {
 775         const char *kstar = strchr(key, '*');
 776         size_t klen;
 777         size_t ksuffixlen;
 778         size_t namelen;
 779         int ret;
 780         if (!kstar)
 781                 die("Key '%s' of pattern had no '*'", key);
 782         klen = kstar - key;
 783         ksuffixlen = strlen(kstar + 1);
 784         namelen = strlen(name);
 785         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 786                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 787         if (ret && value) {
 788                 const char *vstar = strchr(value, '*');
 789                 size_t vlen;
 790                 size_t vsuffixlen;
 791                 if (!vstar)
 792                         die("Value '%s' of pattern has no '*'", value);
 793                 vlen = vstar - value;
 794                 vsuffixlen = strlen(vstar + 1);
 795                 *result = xmalloc(vlen + vsuffixlen +
 796                                   strlen(name) -
 797                                   klen - ksuffixlen + 1);
 798                 strncpy(*result, value, vlen);
 799                 strncpy(*result + vlen,
 800                         name + klen, namelen - klen - ksuffixlen);
 801                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
 802                        vstar + 1);
 803         }
 804         return ret;
 805 }
 806
 807 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 808 {
 809         int find_src = refspec->src == NULL;
 810         char *needle, **result;
 811         int i;
 812
 813         if (find_src) {
 814                 if (!refspec->dst)
 815                         return error("find_tracking: need either src or dst");
 816                 needle = refspec->dst;
 817                 result = &refspec->src;
 818         } else {
 819                 needle = refspec->src;
 820                 result = &refspec->dst;
 821         }
 822
 823         for (i = 0; i < remote->fetch_refspec_nr; i++) {
 824                 struct refspec *fetch = &remote->fetch[i];
 825                 const char *key = find_src ? fetch->dst : fetch->src;
 826                 const char *value = find_src ? fetch->src : fetch->dst;
 827                 if (!fetch->dst)
 828                         continue;
 829                 if (fetch->pattern) {
 830                         if (match_name_with_pattern(key, needle, value, result)) {
 831                                 refspec->force = fetch->force;
 832                                 return 0;
 833                         }
 834                 } else if (!strcmp(needle, key)) {
 835                         *result = xstrdup(value);
 836                         refspec->force = fetch->force;
 837                         return 0;
 838                 }
 839         }
 840         return -1;
 841 }
 842
 843 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 844                 const char *name)
 845 {
 846         size_t len = strlen(name);
 847         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 848         memcpy(ref->name, prefix, prefixlen);
 849         memcpy(ref->name + prefixlen, name, len);
 850         return ref;
 851 }
 852
 853 struct ref *alloc_ref(const char *name)
 854 {
 855         return alloc_ref_with_prefix("", 0, name);
 856 }
 857
 858 static struct ref *copy_ref(const struct ref *ref)
 859 {
 860         struct ref *cpy;
 861         size_t len;
 862         if (!ref)
 863                 return NULL;
 864         len = strlen(ref->name);
 865         cpy = xmalloc(sizeof(struct ref) + len + 1);
 866         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 867         cpy->next = NULL;
 868         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 869         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 870         cpy->peer_ref = copy_ref(ref->peer_ref);
 871         return cpy;
 872 }
 873
 874 struct ref *copy_ref_list(const struct ref *ref)
 875 {
 876         struct ref *ret = NULL;
 877         struct ref **tail = &ret;
 878         while (ref) {
 879                 *tail = copy_ref(ref);
 880                 ref = ref->next;
 881                 tail = &((*tail)->next);
 882         }
 883         return ret;
 884 }
 885
 886 static void free_ref(struct ref *ref)
 887 {
 888         if (!ref)
 889                 return;
 890         free_ref(ref->peer_ref);
 891         free(ref->remote_status);
 892         free(ref->symref);
 893         free(ref);
 894 }
 895
 896 void free_refs(struct ref *ref)
 897 {
 898         struct ref *next;
 899         while (ref) {
 900                 next = ref->next;
 901                 free_ref(ref);
 902                 ref = next;
 903         }
 904 }
 905
 906 static int count_refspec_match(const char *pattern,
 907                                struct ref *refs,
 908                                struct ref **matched_ref)
 909 {
 910         int patlen = strlen(pattern);
 911         struct ref *matched_weak = NULL;
 912         struct ref *matched = NULL;
 913         int weak_match = 0;
 914         int match = 0;
 915
 916         for (weak_match = match = 0; refs; refs = refs->next) {
 917                 char *name = refs->name;
 918                 int namelen = strlen(name);
 919
 920                 if (!refname_match(pattern, name, ref_rev_parse_rules))
 921                         continue;
 922
 923                 /* A match is "weak" if it is with refs outside
 924                  * heads or tags, and did not specify the pattern
 925                  * in full (e.g. "refs/remotes/origin/master") or at
 926                  * least from the toplevel (e.g. "remotes/origin/master");
 927                  * otherwise "git push $URL master" would result in
 928                  * ambiguity between remotes/origin/master and heads/master
 929                  * at the remote site.
 930                  */
 931                 if (namelen != patlen &&
 932                     patlen != namelen - 5 &&
 933                     prefixcmp(name, "refs/heads/") &&
 934                     prefixcmp(name, "refs/tags/")) {
 935                         /* We want to catch the case where only weak
 936                          * matches are found and there are multiple
 937                          * matches, and where more than one strong
 938                          * matches are found, as ambiguous.  One
 939                          * strong match with zero or more weak matches
 940                          * are acceptable as a unique match.
 941                          */
 942                         matched_weak = refs;
 943                         weak_match++;
 944                 }
 945                 else {
 946                         matched = refs;
 947                         match++;
 948                 }
 949         }
 950         if (!matched) {
 951                 *matched_ref = matched_weak;
 952                 return weak_match;
 953         }
 954         else {
 955                 *matched_ref = matched;
 956                 return match;
 957         }
 958 }
 959
 960 static void tail_link_ref(struct ref *ref, struct ref ***tail)
 961 {
 962         **tail = ref;
 963         while (ref->next)
 964                 ref = ref->next;
 965         *tail = &ref->next;
 966 }
 967
 968 static struct ref *try_explicit_object_name(const char *name)
 969 {
 970         unsigned char sha1[20];
 971         struct ref *ref;
 972
 973         if (!*name) {
 974                 ref = alloc_ref("(delete)");
 975                 hashclr(ref->new_sha1);
 976                 return ref;
 977         }
 978         if (get_sha1(name, sha1))
 979                 return NULL;
 980         ref = alloc_ref(name);
 981         hashcpy(ref->new_sha1, sha1);
 982         return ref;
 983 }
 984
 985 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
 986 {
 987         struct ref *ret = alloc_ref(name);
 988         tail_link_ref(ret, tail);
 989         return ret;
 990 }
 991
 992 static char *guess_ref(const char *name, struct ref *peer)
 993 {
 994         struct strbuf buf = STRBUF_INIT;
 995         unsigned char sha1[20];
 996
 997         const char *r = resolve_ref(peer->name, sha1, 1, NULL);
 998         if (!r)
 999                 return NULL;
1000
1001         if (!prefixcmp(r, "refs/heads/"))
1002                 strbuf_addstr(&buf, "refs/heads/");
1003         else if (!prefixcmp(r, "refs/tags/"))
1004                 strbuf_addstr(&buf, "refs/tags/");
1005         else
1006                 return NULL;
1007
1008         strbuf_addstr(&buf, name);
1009         return strbuf_detach(&buf, NULL);
1010 }
1011
1012 static int match_explicit(struct ref *src, struct ref *dst,
1013                           struct ref ***dst_tail,
1014                           struct refspec *rs)
1015 {
1016         struct ref *matched_src, *matched_dst;
1017         int copy_src;
1018
1019         const char *dst_value = rs->dst;
1020         char *dst_guess;
1021
1022         if (rs->pattern || rs->matching)
1023                 return 0;
1024
1025         matched_src = matched_dst = NULL;
1026         switch (count_refspec_match(rs->src, src, &matched_src)) {
1027         case 1:
1028                 copy_src = 1;
1029                 break;
1030         case 0:
1031                 /* The source could be in the get_sha1() format
1032                  * not a reference name.  :refs/other is a
1033                  * way to delete 'other' ref at the remote end.
1034                  */
1035                 matched_src = try_explicit_object_name(rs->src);
1036                 if (!matched_src)
1037                         return error("src refspec %s does not match any.", rs->src);
1038                 copy_src = 0;
1039                 break;
1040         default:
1041                 return error("src refspec %s matches more than one.", rs->src);
1042         }
1043
1044         if (!dst_value) {
1045                 unsigned char sha1[20];
1046                 int flag;
1047
1048                 dst_value = resolve_ref(matched_src->name, sha1, 1, &flag);
1049                 if (!dst_value ||
1050                     ((flag & REF_ISSYMREF) &&
1051                      prefixcmp(dst_value, "refs/heads/")))
1052                         die("%s cannot be resolved to branch.",
1053                             matched_src->name);
1054         }
1055
1056         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1057         case 1:
1058                 break;
1059         case 0:
1060                 if (!memcmp(dst_value, "refs/", 5))
1061                         matched_dst = make_linked_ref(dst_value, dst_tail);
1062                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1063                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1064                 else
1065                         error("unable to push to unqualified destination: %s\n"
1066                               "The destination refspec neither matches an "
1067                               "existing ref on the remote nor\n"
1068                               "begins with refs/, and we are unable to "
1069                               "guess a prefix based on the source ref.",
1070                               dst_value);
1071                 break;
1072         default:
1073                 matched_dst = NULL;
1074                 error("dst refspec %s matches more than one.",
1075                       dst_value);
1076                 break;
1077         }
1078         if (!matched_dst)
1079                 return -1;
1080         if (matched_dst->peer_ref)
1081                 return error("dst ref %s receives from more than one src.",
1082                       matched_dst->name);
1083         else {
1084                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1085                 matched_dst->force = rs->force;
1086         }
1087         return 0;
1088 }
1089
1090 static int match_explicit_refs(struct ref *src, struct ref *dst,
1091                                struct ref ***dst_tail, struct refspec *rs,
1092                                int rs_nr)
1093 {
1094         int i, errs;
1095         for (i = errs = 0; i < rs_nr; i++)
1096                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1097         return errs;
1098 }
1099
1100 static const struct refspec *check_pattern_match(const struct refspec *rs,
1101                                                  int rs_nr,
1102                                                  const struct ref *src)
1103 {
1104         int i;
1105         int matching_refs = -1;
1106         for (i = 0; i < rs_nr; i++) {
1107                 if (rs[i].matching &&
1108                     (matching_refs == -1 || rs[i].force)) {
1109                         matching_refs = i;
1110                         continue;
1111                 }
1112
1113                 if (rs[i].pattern && match_name_with_pattern(rs[i].src, src->name,
1114                                                              NULL, NULL))
1115                         return rs + i;
1116         }
1117         if (matching_refs != -1)
1118                 return rs + matching_refs;
1119         else
1120                 return NULL;
1121 }
1122
1123 static struct ref **tail_ref(struct ref **head)
1124 {
1125         struct ref **tail = head;
1126         while (*tail)
1127                 tail = &((*tail)->next);
1128         return tail;
1129 }
1130
1131 /*
1132  * Note. This is used only by "push"; refspec matching rules for
1133  * push and fetch are subtly different, so do not try to reuse it
1134  * without thinking.
1135  */
1136 int match_refs(struct ref *src, struct ref **dst,
1137                int nr_refspec, const char **refspec, int flags)
1138 {
1139         struct refspec *rs;
1140         int send_all = flags & MATCH_REFS_ALL;
1141         int send_mirror = flags & MATCH_REFS_MIRROR;
1142         int errs;
1143         static const char *default_refspec[] = { ":", NULL };
1144         struct ref **dst_tail = tail_ref(dst);
1145
1146         if (!nr_refspec) {
1147                 nr_refspec = 1;
1148                 refspec = default_refspec;
1149         }
1150         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1151         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1152
1153         /* pick the remainder */
1154         for ( ; src; src = src->next) {
1155                 struct ref *dst_peer;
1156                 const struct refspec *pat = NULL;
1157                 char *dst_name;
1158                 if (src->peer_ref)
1159                         continue;
1160
1161                 pat = check_pattern_match(rs, nr_refspec, src);
1162                 if (!pat)
1163                         continue;
1164
1165                 if (pat->matching) {
1166                         /*
1167                          * "matching refs"; traditionally we pushed everything
1168                          * including refs outside refs/heads/ hierarchy, but
1169                          * that does not make much sense these days.
1170                          */
1171                         if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
1172                                 continue;
1173                         dst_name = xstrdup(src->name);
1174
1175                 } else {
1176                         const char *dst_side = pat->dst ? pat->dst : pat->src;
1177                         if (!match_name_with_pattern(pat->src, src->name,
1178                                                      dst_side, &dst_name))
1179                                 die("Didn't think it matches any more");
1180                 }
1181                 dst_peer = find_ref_by_name(*dst, dst_name);
1182                 if (dst_peer) {
1183                         if (dst_peer->peer_ref)
1184                                 /* We're already sending something to this ref. */
1185                                 goto free_name;
1186
1187                 } else {
1188                         if (pat->matching && !(send_all || send_mirror))
1189                                 /*
1190                                  * Remote doesn't have it, and we have no
1191                                  * explicit pattern, and we don't have
1192                                  * --all nor --mirror.
1193                                  */
1194                                 goto free_name;
1195
1196                         /* Create a new one and link it */
1197                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1198                         hashcpy(dst_peer->new_sha1, src->new_sha1);
1199                 }
1200                 dst_peer->peer_ref = copy_ref(src);
1201                 dst_peer->force = pat->force;
1202         free_name:
1203                 free(dst_name);
1204         }
1205         if (errs)
1206                 return -1;
1207         return 0;
1208 }
1209
1210 struct branch *branch_get(const char *name)
1211 {
1212         struct branch *ret;
1213
1214         read_config();
1215         if (!name || !*name || !strcmp(name, "HEAD"))
1216                 ret = current_branch;
1217         else
1218                 ret = make_branch(name, 0);
1219         if (ret && ret->remote_name) {
1220                 ret->remote = remote_get(ret->remote_name);
1221                 if (ret->merge_nr) {
1222                         int i;
1223                         ret->merge = xcalloc(sizeof(*ret->merge),
1224                                              ret->merge_nr);
1225                         for (i = 0; i < ret->merge_nr; i++) {
1226                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1227                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1228                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1229                                     && !strcmp(ret->remote_name, "."))
1230                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1231                         }
1232                 }
1233         }
1234         return ret;
1235 }
1236
1237 int branch_has_merge_config(struct branch *branch)
1238 {
1239         return branch && !!branch->merge;
1240 }
1241
1242 int branch_merge_matches(struct branch *branch,
1243                                  int i,
1244                                  const char *refname)
1245 {
1246         if (!branch || i < 0 || i >= branch->merge_nr)
1247                 return 0;
1248         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1249 }
1250
1251 static struct ref *get_expanded_map(const struct ref *remote_refs,
1252                                     const struct refspec *refspec)
1253 {
1254         const struct ref *ref;
1255         struct ref *ret = NULL;
1256         struct ref **tail = &ret;
1257
1258         char *expn_name;
1259
1260         for (ref = remote_refs; ref; ref = ref->next) {
1261                 if (strchr(ref->name, '^'))
1262                         continue; /* a dereference item */
1263                 if (match_name_with_pattern(refspec->src, ref->name,
1264                                             refspec->dst, &expn_name)) {
1265                         struct ref *cpy = copy_ref(ref);
1266
1267                         cpy->peer_ref = alloc_ref(expn_name);
1268                         free(expn_name);
1269                         if (refspec->force)
1270                                 cpy->peer_ref->force = 1;
1271                         *tail = cpy;
1272                         tail = &cpy->next;
1273                 }
1274         }
1275
1276         return ret;
1277 }
1278
1279 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1280 {
1281         const struct ref *ref;
1282         for (ref = refs; ref; ref = ref->next) {
1283                 if (refname_match(name, ref->name, ref_fetch_rules))
1284                         return ref;
1285         }
1286         return NULL;
1287 }
1288
1289 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1290 {
1291         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1292
1293         if (!ref)
1294                 return NULL;
1295
1296         return copy_ref(ref);
1297 }
1298
1299 static struct ref *get_local_ref(const char *name)
1300 {
1301         if (!name || name[0] == '\0')
1302                 return NULL;
1303
1304         if (!prefixcmp(name, "refs/"))
1305                 return alloc_ref(name);
1306
1307         if (!prefixcmp(name, "heads/") ||
1308             !prefixcmp(name, "tags/") ||
1309             !prefixcmp(name, "remotes/"))
1310                 return alloc_ref_with_prefix("refs/", 5, name);
1311
1312         return alloc_ref_with_prefix("refs/heads/", 11, name);
1313 }
1314
1315 int get_fetch_map(const struct ref *remote_refs,
1316                   const struct refspec *refspec,
1317                   struct ref ***tail,
1318                   int missing_ok)
1319 {
1320         struct ref *ref_map, **rmp;
1321
1322         if (refspec->pattern) {
1323                 ref_map = get_expanded_map(remote_refs, refspec);
1324         } else {
1325                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1326
1327                 ref_map = get_remote_ref(remote_refs, name);
1328                 if (!missing_ok && !ref_map)
1329                         die("Couldn't find remote ref %s", name);
1330                 if (ref_map) {
1331                         ref_map->peer_ref = get_local_ref(refspec->dst);
1332                         if (ref_map->peer_ref && refspec->force)
1333                                 ref_map->peer_ref->force = 1;
1334                 }
1335         }
1336
1337         for (rmp = &ref_map; *rmp; ) {
1338                 if ((*rmp)->peer_ref) {
1339                         int st = check_ref_format((*rmp)->peer_ref->name + 5);
1340                         if (st && st != CHECK_REF_FORMAT_ONELEVEL) {
1341                                 struct ref *ignore = *rmp;
1342                                 error("* Ignoring funny ref '%s' locally",
1343                                       (*rmp)->peer_ref->name);
1344                                 *rmp = (*rmp)->next;
1345                                 free(ignore->peer_ref);
1346                                 free(ignore);
1347                                 continue;
1348                         }
1349                 }
1350                 rmp = &((*rmp)->next);
1351         }
1352
1353         if (ref_map)
1354                 tail_link_ref(ref_map, tail);
1355
1356         return 0;
1357 }
1358
1359 int resolve_remote_symref(struct ref *ref, struct ref *list)
1360 {
1361         if (!ref->symref)
1362                 return 0;
1363         for (; list; list = list->next)
1364                 if (!strcmp(ref->symref, list->name)) {
1365                         hashcpy(ref->old_sha1, list->old_sha1);
1366                         return 0;
1367                 }
1368         return 1;
1369 }
1370
1371 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1372 {
1373         while (list) {
1374                 struct commit_list *temp = list;
1375                 temp->item->object.flags &= ~mark;
1376                 list = temp->next;
1377                 free(temp);
1378         }
1379 }
1380
1381 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1382 {
1383         struct object *o;
1384         struct commit *old, *new;
1385         struct commit_list *list, *used;
1386         int found = 0;
1387
1388         /* Both new and old must be commit-ish and new is descendant of
1389          * old.  Otherwise we require --force.
1390          */
1391         o = deref_tag(parse_object(old_sha1), NULL, 0);
1392         if (!o || o->type != OBJ_COMMIT)
1393                 return 0;
1394         old = (struct commit *) o;
1395
1396         o = deref_tag(parse_object(new_sha1), NULL, 0);
1397         if (!o || o->type != OBJ_COMMIT)
1398                 return 0;
1399         new = (struct commit *) o;
1400
1401         if (parse_commit(new) < 0)
1402                 return 0;
1403
1404         used = list = NULL;
1405         commit_list_insert(new, &list);
1406         while (list) {
1407                 new = pop_most_recent_commit(&list, TMP_MARK);
1408                 commit_list_insert(new, &used);
1409                 if (new == old) {
1410                         found = 1;
1411                         break;
1412                 }
1413         }
1414         unmark_and_free(list, TMP_MARK);
1415         unmark_and_free(used, TMP_MARK);
1416         return found;
1417 }
1418
1419 /*
1420  * Return true if there is anything to report, otherwise false.
1421  */
1422 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1423 {
1424         unsigned char sha1[20];
1425         struct commit *ours, *theirs;
1426         char symmetric[84];
1427         struct rev_info revs;
1428         const char *rev_argv[10], *base;
1429         int rev_argc;
1430
1431         /*
1432          * Nothing to report unless we are marked to build on top of
1433          * somebody else.
1434          */
1435         if (!branch ||
1436             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1437                 return 0;
1438
1439         /*
1440          * If what we used to build on no longer exists, there is
1441          * nothing to report.
1442          */
1443         base = branch->merge[0]->dst;
1444         if (!resolve_ref(base, sha1, 1, NULL))
1445                 return 0;
1446         theirs = lookup_commit_reference(sha1);
1447         if (!theirs)
1448                 return 0;
1449
1450         if (!resolve_ref(branch->refname, sha1, 1, NULL))
1451                 return 0;
1452         ours = lookup_commit_reference(sha1);
1453         if (!ours)
1454                 return 0;
1455
1456         /* are we the same? */
1457         if (theirs == ours)
1458                 return 0;
1459
1460         /* Run "rev-list --left-right ours...theirs" internally... */
1461         rev_argc = 0;
1462         rev_argv[rev_argc++] = NULL;
1463         rev_argv[rev_argc++] = "--left-right";
1464         rev_argv[rev_argc++] = symmetric;
1465         rev_argv[rev_argc++] = "--";
1466         rev_argv[rev_argc] = NULL;
1467
1468         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1469         strcpy(symmetric + 40, "...");
1470         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1471
1472         init_revisions(&revs, NULL);
1473         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1474         prepare_revision_walk(&revs);
1475
1476         /* ... and count the commits on each side. */
1477         *num_ours = 0;
1478         *num_theirs = 0;
1479         while (1) {
1480                 struct commit *c = get_revision(&revs);
1481                 if (!c)
1482                         break;
1483                 if (c->object.flags & SYMMETRIC_LEFT)
1484                         (*num_ours)++;
1485                 else
1486                         (*num_theirs)++;
1487         }
1488
1489         /* clear object flags smudged by the above traversal */
1490         clear_commit_marks(ours, ALL_REV_FLAGS);
1491         clear_commit_marks(theirs, ALL_REV_FLAGS);
1492         return 1;
1493 }
1494
1495 /*
1496  * Return true when there is anything to report, otherwise false.
1497  */
1498 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1499 {
1500         int num_ours, num_theirs;
1501         const char *base;
1502
1503         if (!stat_tracking_info(branch, &num_ours, &num_theirs))
1504                 return 0;
1505
1506         base = branch->merge[0]->dst;
1507         base = shorten_unambiguous_ref(base, 0);
1508         if (!num_theirs)
1509                 strbuf_addf(sb, "Your branch is ahead of '%s' "
1510                             "by %d commit%s.\n",
1511                             base, num_ours, (num_ours == 1) ? "" : "s");
1512         else if (!num_ours)
1513                 strbuf_addf(sb, "Your branch is behind '%s' "
1514                             "by %d commit%s, "
1515                             "and can be fast-forwarded.\n",
1516                             base, num_theirs, (num_theirs == 1) ? "" : "s");
1517         else
1518                 strbuf_addf(sb, "Your branch and '%s' have diverged,\n"
1519                             "and have %d and %d different commit(s) each, "
1520                             "respectively.\n",
1521                             base, num_ours, num_theirs);
1522         return 1;
1523 }
1524
1525 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1526 {
1527         struct ref ***local_tail = cb_data;
1528         struct ref *ref;
1529         int len;
1530
1531         /* we already know it starts with refs/ to get here */
1532         if (check_ref_format(refname + 5))
1533                 return 0;
1534
1535         len = strlen(refname) + 1;
1536         ref = xcalloc(1, sizeof(*ref) + len);
1537         hashcpy(ref->new_sha1, sha1);
1538         memcpy(ref->name, refname, len);
1539         **local_tail = ref;
1540         *local_tail = &ref->next;
1541         return 0;
1542 }
1543
1544 struct ref *get_local_heads(void)
1545 {
1546         struct ref *local_refs = NULL, **local_tail = &local_refs;
1547         for_each_ref(one_local_ref, &local_tail);
1548         return local_refs;
1549 }
1550
1551 struct ref *guess_remote_head(const struct ref *head,
1552                               const struct ref *refs,
1553                               int all)
1554 {
1555         const struct ref *r;
1556         struct ref *list = NULL;
1557         struct ref **tail = &list;
1558
1559         if (!head)
1560                 return NULL;
1561
1562         /*
1563          * Some transports support directly peeking at
1564          * where HEAD points; if that is the case, then
1565          * we don't have to guess.
1566          */
1567         if (head->symref)
1568                 return copy_ref(find_ref_by_name(refs, head->symref));
1569
1570         /* If refs/heads/master could be right, it is. */
1571         if (!all) {
1572                 r = find_ref_by_name(refs, "refs/heads/master");
1573                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1574                         return copy_ref(r);
1575         }
1576
1577         /* Look for another ref that points there */
1578         for (r = refs; r; r = r->next) {
1579                 if (r != head && !hashcmp(r->old_sha1, head->old_sha1)) {
1580                         *tail = copy_ref(r);
1581                         tail = &((*tail)->next);
1582                         if (!all)
1583                                 break;
1584                 }
1585         }
1586
1587         return list;
1588 }