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 #include "string-list.h"
  10
  11 static struct refspec s_tag_refspec = {
  12         0,
  13         1,
  14         0,
  15         "refs/tags/*",
  16         "refs/tags/*"
  17 };
  18
  19 const struct refspec *tag_refspec = &s_tag_refspec;
  20
  21 struct counted_string {
  22         size_t len;
  23         const char *s;
  24 };
  25 struct rewrite {
  26         const char *base;
  27         size_t baselen;
  28         struct counted_string *instead_of;
  29         int instead_of_nr;
  30         int instead_of_alloc;
  31 };
  32 struct rewrites {
  33         struct rewrite **rewrite;
  34         int rewrite_alloc;
  35         int rewrite_nr;
  36 };
  37
  38 static struct remote **remotes;
  39 static int remotes_alloc;
  40 static int remotes_nr;
  41
  42 static struct branch **branches;
  43 static int branches_alloc;
  44 static int branches_nr;
  45
  46 static struct branch *current_branch;
  47 static const char *default_remote_name;
  48 static int explicit_default_remote_name;
  49
  50 static struct rewrites rewrites;
  51 static struct rewrites rewrites_push;
  52
  53 #define BUF_SIZE (2048)
  54 static char buffer[BUF_SIZE];
  55
  56 static int valid_remote(const struct remote *remote)
  57 {
  58         return (!!remote->url) || (!!remote->foreign_vcs);
  59 }
  60
  61 static const char *alias_url(const char *url, struct rewrites *r)
  62 {
  63         int i, j;
  64         char *ret;
  65         struct counted_string *longest;
  66         int longest_i;
  67
  68         longest = NULL;
  69         longest_i = -1;
  70         for (i = 0; i < r->rewrite_nr; i++) {
  71                 if (!r->rewrite[i])
  72                         continue;
  73                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  74                         if (!prefixcmp(url, r->rewrite[i]->instead_of[j].s) &&
  75                             (!longest ||
  76                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  77                                 longest = &(r->rewrite[i]->instead_of[j]);
  78                                 longest_i = i;
  79                         }
  80                 }
  81         }
  82         if (!longest)
  83                 return url;
  84
  85         ret = xmalloc(r->rewrite[longest_i]->baselen +
  86                      (strlen(url) - longest->len) + 1);
  87         strcpy(ret, r->rewrite[longest_i]->base);
  88         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
  89         return ret;
  90 }
  91
  92 static void add_push_refspec(struct remote *remote, const char *ref)
  93 {
  94         ALLOC_GROW(remote->push_refspec,
  95                    remote->push_refspec_nr + 1,
  96                    remote->push_refspec_alloc);
  97         remote->push_refspec[remote->push_refspec_nr++] = ref;
  98 }
  99
 100 static void add_fetch_refspec(struct remote *remote, const char *ref)
 101 {
 102         ALLOC_GROW(remote->fetch_refspec,
 103                    remote->fetch_refspec_nr + 1,
 104                    remote->fetch_refspec_alloc);
 105         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
 106 }
 107
 108 static void add_url(struct remote *remote, const char *url)
 109 {
 110         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
 111         remote->url[remote->url_nr++] = url;
 112 }
 113
 114 static void add_pushurl(struct remote *remote, const char *pushurl)
 115 {
 116         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
 117         remote->pushurl[remote->pushurl_nr++] = pushurl;
 118 }
 119
 120 static void add_pushurl_alias(struct remote *remote, const char *url)
 121 {
 122         const char *pushurl = alias_url(url, &rewrites_push);
 123         if (pushurl != url)
 124                 add_pushurl(remote, pushurl);
 125 }
 126
 127 static void add_url_alias(struct remote *remote, const char *url)
 128 {
 129         add_url(remote, alias_url(url, &rewrites));
 130         add_pushurl_alias(remote, url);
 131 }
 132
 133 static struct remote *make_remote(const char *name, int len)
 134 {
 135         struct remote *ret;
 136         int i;
 137
 138         for (i = 0; i < remotes_nr; i++) {
 139                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
 140                            !remotes[i]->name[len]) :
 141                     !strcmp(name, remotes[i]->name))
 142                         return remotes[i];
 143         }
 144
 145         ret = xcalloc(1, sizeof(struct remote));
 146         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 147         remotes[remotes_nr++] = ret;
 148         if (len)
 149                 ret->name = xstrndup(name, len);
 150         else
 151                 ret->name = xstrdup(name);
 152         return ret;
 153 }
 154
 155 static void add_merge(struct branch *branch, const char *name)
 156 {
 157         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 158                    branch->merge_alloc);
 159         branch->merge_name[branch->merge_nr++] = name;
 160 }
 161
 162 static struct branch *make_branch(const char *name, int len)
 163 {
 164         struct branch *ret;
 165         int i;
 166         char *refname;
 167
 168         for (i = 0; i < branches_nr; i++) {
 169                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 170                            !branches[i]->name[len]) :
 171                     !strcmp(name, branches[i]->name))
 172                         return branches[i];
 173         }
 174
 175         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 176         ret = xcalloc(1, sizeof(struct branch));
 177         branches[branches_nr++] = ret;
 178         if (len)
 179                 ret->name = xstrndup(name, len);
 180         else
 181                 ret->name = xstrdup(name);
 182         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
 183         strcpy(refname, "refs/heads/");
 184         strcpy(refname + strlen("refs/heads/"), ret->name);
 185         ret->refname = refname;
 186
 187         return ret;
 188 }
 189
 190 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 191 {
 192         struct rewrite *ret;
 193         int i;
 194
 195         for (i = 0; i < r->rewrite_nr; i++) {
 196                 if (len
 197                     ? (len == r->rewrite[i]->baselen &&
 198                        !strncmp(base, r->rewrite[i]->base, len))
 199                     : !strcmp(base, r->rewrite[i]->base))
 200                         return r->rewrite[i];
 201         }
 202
 203         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 204         ret = xcalloc(1, sizeof(struct rewrite));
 205         r->rewrite[r->rewrite_nr++] = ret;
 206         if (len) {
 207                 ret->base = xstrndup(base, len);
 208                 ret->baselen = len;
 209         }
 210         else {
 211                 ret->base = xstrdup(base);
 212                 ret->baselen = strlen(base);
 213         }
 214         return ret;
 215 }
 216
 217 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 218 {
 219         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 220         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 221         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 222         rewrite->instead_of_nr++;
 223 }
 224
 225 static void read_remotes_file(struct remote *remote)
 226 {
 227         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 228
 229         if (!f)
 230                 return;
 231         remote->origin = REMOTE_REMOTES;
 232         while (fgets(buffer, BUF_SIZE, f)) {
 233                 int value_list;
 234                 char *s, *p;
 235
 236                 if (!prefixcmp(buffer, "URL:")) {
 237                         value_list = 0;
 238                         s = buffer + 4;
 239                 } else if (!prefixcmp(buffer, "Push:")) {
 240                         value_list = 1;
 241                         s = buffer + 5;
 242                 } else if (!prefixcmp(buffer, "Pull:")) {
 243                         value_list = 2;
 244                         s = buffer + 5;
 245                 } else
 246                         continue;
 247
 248                 while (isspace(*s))
 249                         s++;
 250                 if (!*s)
 251                         continue;
 252
 253                 p = s + strlen(s);
 254                 while (isspace(p[-1]))
 255                         *--p = 0;
 256
 257                 switch (value_list) {
 258                 case 0:
 259                         add_url_alias(remote, xstrdup(s));
 260                         break;
 261                 case 1:
 262                         add_push_refspec(remote, xstrdup(s));
 263                         break;
 264                 case 2:
 265                         add_fetch_refspec(remote, xstrdup(s));
 266                         break;
 267                 }
 268         }
 269         fclose(f);
 270 }
 271
 272 static void read_branches_file(struct remote *remote)
 273 {
 274         const char *slash = strchr(remote->name, '/');
 275         char *frag;
 276         struct strbuf branch = STRBUF_INIT;
 277         int n = slash ? slash - remote->name : 1000;
 278         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
 279         char *s, *p;
 280         int len;
 281
 282         if (!f)
 283                 return;
 284         s = fgets(buffer, BUF_SIZE, f);
 285         fclose(f);
 286         if (!s)
 287                 return;
 288         while (isspace(*s))
 289                 s++;
 290         if (!*s)
 291                 return;
 292         remote->origin = REMOTE_BRANCHES;
 293         p = s + strlen(s);
 294         while (isspace(p[-1]))
 295                 *--p = 0;
 296         len = p - s;
 297         if (slash)
 298                 len += strlen(slash);
 299         p = xmalloc(len + 1);
 300         strcpy(p, s);
 301         if (slash)
 302                 strcat(p, slash);
 303
 304         /*
 305          * With "slash", e.g. "git fetch jgarzik/netdev-2.6" when
 306          * reading from $GIT_DIR/branches/jgarzik fetches "HEAD" from
 307          * the partial URL obtained from the branches file plus
 308          * "/netdev-2.6" and does not store it in any tracking ref.
 309          * #branch specifier in the file is ignored.
 310          *
 311          * Otherwise, the branches file would have URL and optionally
 312          * #branch specified.  The "master" (or specified) branch is
 313          * fetched and stored in the local branch of the same name.
 314          */
 315         frag = strchr(p, '#');
 316         if (frag) {
 317                 *(frag++) = '\0';
 318                 strbuf_addf(&branch, "refs/heads/%s", frag);
 319         } else
 320                 strbuf_addstr(&branch, "refs/heads/master");
 321         if (!slash) {
 322                 strbuf_addf(&branch, ":refs/heads/%s", remote->name);
 323         } else {
 324                 strbuf_reset(&branch);
 325                 strbuf_addstr(&branch, "HEAD:");
 326         }
 327         add_url_alias(remote, p);
 328         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
 329         /*
 330          * Cogito compatible push: push current HEAD to remote #branch
 331          * (master if missing)
 332          */
 333         strbuf_init(&branch, 0);
 334         strbuf_addstr(&branch, "HEAD");
 335         if (frag)
 336                 strbuf_addf(&branch, ":refs/heads/%s", frag);
 337         else
 338                 strbuf_addstr(&branch, ":refs/heads/master");
 339         add_push_refspec(remote, strbuf_detach(&branch, NULL));
 340         remote->fetch_tags = 1; /* always auto-follow */
 341 }
 342
 343 static int handle_config(const char *key, const char *value, void *cb)
 344 {
 345         const char *name;
 346         const char *subkey;
 347         struct remote *remote;
 348         struct branch *branch;
 349         if (!prefixcmp(key, "branch.")) {
 350                 name = key + 7;
 351                 subkey = strrchr(name, '.');
 352                 if (!subkey)
 353                         return 0;
 354                 branch = make_branch(name, subkey - name);
 355                 if (!strcmp(subkey, ".remote")) {
 356                         if (!value)
 357                                 return config_error_nonbool(key);
 358                         branch->remote_name = xstrdup(value);
 359                         if (branch == current_branch) {
 360                                 default_remote_name = branch->remote_name;
 361                                 explicit_default_remote_name = 1;
 362                         }
 363                 } else if (!strcmp(subkey, ".merge")) {
 364                         if (!value)
 365                                 return config_error_nonbool(key);
 366                         add_merge(branch, xstrdup(value));
 367                 }
 368                 return 0;
 369         }
 370         if (!prefixcmp(key, "url.")) {
 371                 struct rewrite *rewrite;
 372                 name = key + 4;
 373                 subkey = strrchr(name, '.');
 374                 if (!subkey)
 375                         return 0;
 376                 if (!strcmp(subkey, ".insteadof")) {
 377                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 378                         if (!value)
 379                                 return config_error_nonbool(key);
 380                         add_instead_of(rewrite, xstrdup(value));
 381                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 382                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 383                         if (!value)
 384                                 return config_error_nonbool(key);
 385                         add_instead_of(rewrite, xstrdup(value));
 386                 }
 387         }
 388         if (prefixcmp(key,  "remote."))
 389                 return 0;
 390         name = key + 7;
 391         if (*name == '/') {
 392                 warning("Config remote shorthand cannot begin with '/': %s",
 393                         name);
 394                 return 0;
 395         }
 396         subkey = strrchr(name, '.');
 397         if (!subkey)
 398                 return 0;
 399         remote = make_remote(name, subkey - name);
 400         remote->origin = REMOTE_CONFIG;
 401         if (!strcmp(subkey, ".mirror"))
 402                 remote->mirror = git_config_bool(key, value);
 403         else if (!strcmp(subkey, ".skipdefaultupdate"))
 404                 remote->skip_default_update = git_config_bool(key, value);
 405         else if (!strcmp(subkey, ".skipfetchall"))
 406                 remote->skip_default_update = git_config_bool(key, value);
 407         else if (!strcmp(subkey, ".url")) {
 408                 const char *v;
 409                 if (git_config_string(&v, key, value))
 410                         return -1;
 411                 add_url(remote, v);
 412         } else if (!strcmp(subkey, ".pushurl")) {
 413                 const char *v;
 414                 if (git_config_string(&v, key, value))
 415                         return -1;
 416                 add_pushurl(remote, v);
 417         } else if (!strcmp(subkey, ".push")) {
 418                 const char *v;
 419                 if (git_config_string(&v, key, value))
 420                         return -1;
 421                 add_push_refspec(remote, v);
 422         } else if (!strcmp(subkey, ".fetch")) {
 423                 const char *v;
 424                 if (git_config_string(&v, key, value))
 425                         return -1;
 426                 add_fetch_refspec(remote, v);
 427         } else if (!strcmp(subkey, ".receivepack")) {
 428                 const char *v;
 429                 if (git_config_string(&v, key, value))
 430                         return -1;
 431                 if (!remote->receivepack)
 432                         remote->receivepack = v;
 433                 else
 434                         error("more than one receivepack given, using the first");
 435         } else if (!strcmp(subkey, ".uploadpack")) {
 436                 const char *v;
 437                 if (git_config_string(&v, key, value))
 438                         return -1;
 439                 if (!remote->uploadpack)
 440                         remote->uploadpack = v;
 441                 else
 442                         error("more than one uploadpack given, using the first");
 443         } else if (!strcmp(subkey, ".tagopt")) {
 444                 if (!strcmp(value, "--no-tags"))
 445                         remote->fetch_tags = -1;
 446                 else if (!strcmp(value, "--tags"))
 447                         remote->fetch_tags = 2;
 448         } else if (!strcmp(subkey, ".proxy")) {
 449                 return git_config_string((const char **)&remote->http_proxy,
 450                                          key, value);
 451         } else if (!strcmp(subkey, ".vcs")) {
 452                 return git_config_string(&remote->foreign_vcs, key, value);
 453         }
 454         return 0;
 455 }
 456
 457 static void alias_all_urls(void)
 458 {
 459         int i, j;
 460         for (i = 0; i < remotes_nr; i++) {
 461                 int add_pushurl_aliases;
 462                 if (!remotes[i])
 463                         continue;
 464                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 465                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 466                 }
 467                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 468                 for (j = 0; j < remotes[i]->url_nr; j++) {
 469                         if (add_pushurl_aliases)
 470                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 471                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 472                 }
 473         }
 474 }
 475
 476 static void read_config(void)
 477 {
 478         unsigned char sha1[20];
 479         const char *head_ref;
 480         int flag;
 481         if (default_remote_name) /* did this already */
 482                 return;
 483         default_remote_name = xstrdup("origin");
 484         current_branch = NULL;
 485         head_ref = resolve_ref("HEAD", sha1, 0, &flag);
 486         if (head_ref && (flag & REF_ISSYMREF) &&
 487             !prefixcmp(head_ref, "refs/heads/")) {
 488                 current_branch =
 489                         make_branch(head_ref + strlen("refs/heads/"), 0);
 490         }
 491         git_config(handle_config, NULL);
 492         alias_all_urls();
 493 }
 494
 495 /*
 496  * We need to make sure the tracking branches are well formed, but a
 497  * wildcard refspec in "struct refspec" must have a trailing slash. We
 498  * temporarily drop the trailing '/' while calling check_ref_format(),
 499  * and put it back.  The caller knows that a CHECK_REF_FORMAT_ONELEVEL
 500  * error return is Ok for a wildcard refspec.
 501  */
 502 static int verify_refname(char *name, int is_glob)
 503 {
 504         int result;
 505
 506         result = check_ref_format(name);
 507         if (is_glob && result == CHECK_REF_FORMAT_WILDCARD)
 508                 result = CHECK_REF_FORMAT_OK;
 509         return result;
 510 }
 511
 512 /*
 513  * This function frees a refspec array.
 514  * Warning: code paths should be checked to ensure that the src
 515  *          and dst pointers are always freeable pointers as well
 516  *          as the refspec pointer itself.
 517  */
 518 static void free_refspecs(struct refspec *refspec, int nr_refspec)
 519 {
 520         int i;
 521
 522         if (!refspec)
 523                 return;
 524
 525         for (i = 0; i < nr_refspec; i++) {
 526                 free(refspec[i].src);
 527                 free(refspec[i].dst);
 528         }
 529         free(refspec);
 530 }
 531
 532 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 533 {
 534         int i;
 535         int st;
 536         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 537
 538         for (i = 0; i < nr_refspec; i++) {
 539                 size_t llen;
 540                 int is_glob;
 541                 const char *lhs, *rhs;
 542
 543                 is_glob = 0;
 544
 545                 lhs = refspec[i];
 546                 if (*lhs == '+') {
 547                         rs[i].force = 1;
 548                         lhs++;
 549                 }
 550
 551                 rhs = strrchr(lhs, ':');
 552
 553                 /*
 554                  * Before going on, special case ":" (or "+:") as a refspec
 555                  * for matching refs.
 556                  */
 557                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
 558                         rs[i].matching = 1;
 559                         continue;
 560                 }
 561
 562                 if (rhs) {
 563                         size_t rlen = strlen(++rhs);
 564                         is_glob = (1 <= rlen && strchr(rhs, '*'));
 565                         rs[i].dst = xstrndup(rhs, rlen);
 566                 }
 567
 568                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 569                 if (1 <= llen && memchr(lhs, '*', llen)) {
 570                         if ((rhs && !is_glob) || (!rhs && fetch))
 571                                 goto invalid;
 572                         is_glob = 1;
 573                 } else if (rhs && is_glob) {
 574                         goto invalid;
 575                 }
 576
 577                 rs[i].pattern = is_glob;
 578                 rs[i].src = xstrndup(lhs, llen);
 579
 580                 if (fetch) {
 581                         /*
 582                          * LHS
 583                          * - empty is allowed; it means HEAD.
 584                          * - otherwise it must be a valid looking ref.
 585                          */
 586                         if (!*rs[i].src)
 587                                 ; /* empty is ok */
 588                         else {
 589                                 st = verify_refname(rs[i].src, is_glob);
 590                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 591                                         goto invalid;
 592                         }
 593                         /*
 594                          * RHS
 595                          * - missing is ok, and is same as empty.
 596                          * - empty is ok; it means not to store.
 597                          * - otherwise it must be a valid looking ref.
 598                          */
 599                         if (!rs[i].dst) {
 600                                 ; /* ok */
 601                         } else if (!*rs[i].dst) {
 602                                 ; /* ok */
 603                         } else {
 604                                 st = verify_refname(rs[i].dst, is_glob);
 605                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 606                                         goto invalid;
 607                         }
 608                 } else {
 609                         /*
 610                          * LHS
 611                          * - empty is allowed; it means delete.
 612                          * - when wildcarded, it must be a valid looking ref.
 613                          * - otherwise, it must be an extended SHA-1, but
 614                          *   there is no existing way to validate this.
 615                          */
 616                         if (!*rs[i].src)
 617                                 ; /* empty is ok */
 618                         else if (is_glob) {
 619                                 st = verify_refname(rs[i].src, is_glob);
 620                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 621                                         goto invalid;
 622                         }
 623                         else
 624                                 ; /* anything goes, for now */
 625                         /*
 626                          * RHS
 627                          * - missing is allowed, but LHS then must be a
 628                          *   valid looking ref.
 629                          * - empty is not allowed.
 630                          * - otherwise it must be a valid looking ref.
 631                          */
 632                         if (!rs[i].dst) {
 633                                 st = verify_refname(rs[i].src, is_glob);
 634                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 635                                         goto invalid;
 636                         } else if (!*rs[i].dst) {
 637                                 goto invalid;
 638                         } else {
 639                                 st = verify_refname(rs[i].dst, is_glob);
 640                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 641                                         goto invalid;
 642                         }
 643                 }
 644         }
 645         return rs;
 646
 647  invalid:
 648         if (verify) {
 649                 /*
 650                  * nr_refspec must be greater than zero and i must be valid
 651                  * since it is only possible to reach this point from within
 652                  * the for loop above.
 653                  */
 654                 free_refspecs(rs, i+1);
 655                 return NULL;
 656         }
 657         die("Invalid refspec '%s'", refspec[i]);
 658 }
 659
 660 int valid_fetch_refspec(const char *fetch_refspec_str)
 661 {
 662         const char *fetch_refspec[] = { fetch_refspec_str };
 663         struct refspec *refspec;
 664
 665         refspec = parse_refspec_internal(1, fetch_refspec, 1, 1);
 666         free_refspecs(refspec, 1);
 667         return !!refspec;
 668 }
 669
 670 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 671 {
 672         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 673 }
 674
 675 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 676 {
 677         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 678 }
 679
 680 void free_refspec(int nr_refspec, struct refspec *refspec)
 681 {
 682         int i;
 683         for (i = 0; i < nr_refspec; i++) {
 684                 free(refspec[i].src);
 685                 free(refspec[i].dst);
 686         }
 687         free(refspec);
 688 }
 689
 690 static int valid_remote_nick(const char *name)
 691 {
 692         if (!name[0] || is_dot_or_dotdot(name))
 693                 return 0;
 694         return !strchr(name, '/'); /* no slash */
 695 }
 696
 697 struct remote *remote_get(const char *name)
 698 {
 699         struct remote *ret;
 700         int name_given = 0;
 701
 702         read_config();
 703         if (name)
 704                 name_given = 1;
 705         else {
 706                 name = default_remote_name;
 707                 name_given = explicit_default_remote_name;
 708         }
 709
 710         ret = make_remote(name, 0);
 711         if (valid_remote_nick(name)) {
 712                 if (!valid_remote(ret))
 713                         read_remotes_file(ret);
 714                 if (!valid_remote(ret))
 715                         read_branches_file(ret);
 716         }
 717         if (name_given && !valid_remote(ret))
 718                 add_url_alias(ret, name);
 719         if (!valid_remote(ret))
 720                 return NULL;
 721         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 722         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 723         return ret;
 724 }
 725
 726 int remote_is_configured(const char *name)
 727 {
 728         int i;
 729         read_config();
 730
 731         for (i = 0; i < remotes_nr; i++)
 732                 if (!strcmp(name, remotes[i]->name))
 733                         return 1;
 734         return 0;
 735 }
 736
 737 int for_each_remote(each_remote_fn fn, void *priv)
 738 {
 739         int i, result = 0;
 740         read_config();
 741         for (i = 0; i < remotes_nr && !result; i++) {
 742                 struct remote *r = remotes[i];
 743                 if (!r)
 744                         continue;
 745                 if (!r->fetch)
 746                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 747                                                        r->fetch_refspec);
 748                 if (!r->push)
 749                         r->push = parse_push_refspec(r->push_refspec_nr,
 750                                                      r->push_refspec);
 751                 result = fn(r, priv);
 752         }
 753         return result;
 754 }
 755
 756 void ref_remove_duplicates(struct ref *ref_map)
 757 {
 758         struct string_list refs = { NULL, 0, 0, 0 };
 759         struct string_list_item *item = NULL;
 760         struct ref *prev = NULL, *next = NULL;
 761         for (; ref_map; prev = ref_map, ref_map = next) {
 762                 next = ref_map->next;
 763                 if (!ref_map->peer_ref)
 764                         continue;
 765
 766                 item = string_list_lookup(ref_map->peer_ref->name, &refs);
 767                 if (item) {
 768                         if (strcmp(((struct ref *)item->util)->name,
 769                                    ref_map->name))
 770                                 die("%s tracks both %s and %s",
 771                                     ref_map->peer_ref->name,
 772                                     ((struct ref *)item->util)->name,
 773                                     ref_map->name);
 774                         prev->next = ref_map->next;
 775                         free(ref_map->peer_ref);
 776                         free(ref_map);
 777                         ref_map = prev; /* skip this; we freed it */
 778                         continue;
 779                 }
 780
 781                 item = string_list_insert(ref_map->peer_ref->name, &refs);
 782                 item->util = ref_map;
 783         }
 784         string_list_clear(&refs, 0);
 785 }
 786
 787 int remote_has_url(struct remote *remote, const char *url)
 788 {
 789         int i;
 790         for (i = 0; i < remote->url_nr; i++) {
 791                 if (!strcmp(remote->url[i], url))
 792                         return 1;
 793         }
 794         return 0;
 795 }
 796
 797 static int match_name_with_pattern(const char *key, const char *name,
 798                                    const char *value, char **result)
 799 {
 800         const char *kstar = strchr(key, '*');
 801         size_t klen;
 802         size_t ksuffixlen;
 803         size_t namelen;
 804         int ret;
 805         if (!kstar)
 806                 die("Key '%s' of pattern had no '*'", key);
 807         klen = kstar - key;
 808         ksuffixlen = strlen(kstar + 1);
 809         namelen = strlen(name);
 810         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 811                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 812         if (ret && value) {
 813                 const char *vstar = strchr(value, '*');
 814                 size_t vlen;
 815                 size_t vsuffixlen;
 816                 if (!vstar)
 817                         die("Value '%s' of pattern has no '*'", value);
 818                 vlen = vstar - value;
 819                 vsuffixlen = strlen(vstar + 1);
 820                 *result = xmalloc(vlen + vsuffixlen +
 821                                   strlen(name) -
 822                                   klen - ksuffixlen + 1);
 823                 strncpy(*result, value, vlen);
 824                 strncpy(*result + vlen,
 825                         name + klen, namelen - klen - ksuffixlen);
 826                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
 827                        vstar + 1);
 828         }
 829         return ret;
 830 }
 831
 832 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 833                      const char *name)
 834 {
 835         int i;
 836         char *ret = NULL;
 837         for (i = 0; i < nr_refspec; i++) {
 838                 struct refspec *refspec = refspecs + i;
 839                 if (refspec->pattern) {
 840                         if (match_name_with_pattern(refspec->src, name,
 841                                                     refspec->dst, &ret))
 842                                 return ret;
 843                 } else if (!strcmp(refspec->src, name))
 844                         return strdup(refspec->dst);
 845         }
 846         return NULL;
 847 }
 848
 849 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 850 {
 851         int find_src = refspec->src == NULL;
 852         char *needle, **result;
 853         int i;
 854
 855         if (find_src) {
 856                 if (!refspec->dst)
 857                         return error("find_tracking: need either src or dst");
 858                 needle = refspec->dst;
 859                 result = &refspec->src;
 860         } else {
 861                 needle = refspec->src;
 862                 result = &refspec->dst;
 863         }
 864
 865         for (i = 0; i < remote->fetch_refspec_nr; i++) {
 866                 struct refspec *fetch = &remote->fetch[i];
 867                 const char *key = find_src ? fetch->dst : fetch->src;
 868                 const char *value = find_src ? fetch->src : fetch->dst;
 869                 if (!fetch->dst)
 870                         continue;
 871                 if (fetch->pattern) {
 872                         if (match_name_with_pattern(key, needle, value, result)) {
 873                                 refspec->force = fetch->force;
 874                                 return 0;
 875                         }
 876                 } else if (!strcmp(needle, key)) {
 877                         *result = xstrdup(value);
 878                         refspec->force = fetch->force;
 879                         return 0;
 880                 }
 881         }
 882         return -1;
 883 }
 884
 885 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 886                 const char *name)
 887 {
 888         size_t len = strlen(name);
 889         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 890         memcpy(ref->name, prefix, prefixlen);
 891         memcpy(ref->name + prefixlen, name, len);
 892         return ref;
 893 }
 894
 895 struct ref *alloc_ref(const char *name)
 896 {
 897         return alloc_ref_with_prefix("", 0, name);
 898 }
 899
 900 static struct ref *copy_ref(const struct ref *ref)
 901 {
 902         struct ref *cpy;
 903         size_t len;
 904         if (!ref)
 905                 return NULL;
 906         len = strlen(ref->name);
 907         cpy = xmalloc(sizeof(struct ref) + len + 1);
 908         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 909         cpy->next = NULL;
 910         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 911         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 912         cpy->peer_ref = copy_ref(ref->peer_ref);
 913         return cpy;
 914 }
 915
 916 struct ref *copy_ref_list(const struct ref *ref)
 917 {
 918         struct ref *ret = NULL;
 919         struct ref **tail = &ret;
 920         while (ref) {
 921                 *tail = copy_ref(ref);
 922                 ref = ref->next;
 923                 tail = &((*tail)->next);
 924         }
 925         return ret;
 926 }
 927
 928 static void free_ref(struct ref *ref)
 929 {
 930         if (!ref)
 931                 return;
 932         free_ref(ref->peer_ref);
 933         free(ref->remote_status);
 934         free(ref->symref);
 935         free(ref);
 936 }
 937
 938 void free_refs(struct ref *ref)
 939 {
 940         struct ref *next;
 941         while (ref) {
 942                 next = ref->next;
 943                 free_ref(ref);
 944                 ref = next;
 945         }
 946 }
 947
 948 static int count_refspec_match(const char *pattern,
 949                                struct ref *refs,
 950                                struct ref **matched_ref)
 951 {
 952         int patlen = strlen(pattern);
 953         struct ref *matched_weak = NULL;
 954         struct ref *matched = NULL;
 955         int weak_match = 0;
 956         int match = 0;
 957
 958         for (weak_match = match = 0; refs; refs = refs->next) {
 959                 char *name = refs->name;
 960                 int namelen = strlen(name);
 961
 962                 if (!refname_match(pattern, name, ref_rev_parse_rules))
 963                         continue;
 964
 965                 /* A match is "weak" if it is with refs outside
 966                  * heads or tags, and did not specify the pattern
 967                  * in full (e.g. "refs/remotes/origin/master") or at
 968                  * least from the toplevel (e.g. "remotes/origin/master");
 969                  * otherwise "git push $URL master" would result in
 970                  * ambiguity between remotes/origin/master and heads/master
 971                  * at the remote site.
 972                  */
 973                 if (namelen != patlen &&
 974                     patlen != namelen - 5 &&
 975                     prefixcmp(name, "refs/heads/") &&
 976                     prefixcmp(name, "refs/tags/")) {
 977                         /* We want to catch the case where only weak
 978                          * matches are found and there are multiple
 979                          * matches, and where more than one strong
 980                          * matches are found, as ambiguous.  One
 981                          * strong match with zero or more weak matches
 982                          * are acceptable as a unique match.
 983                          */
 984                         matched_weak = refs;
 985                         weak_match++;
 986                 }
 987                 else {
 988                         matched = refs;
 989                         match++;
 990                 }
 991         }
 992         if (!matched) {
 993                 *matched_ref = matched_weak;
 994                 return weak_match;
 995         }
 996         else {
 997                 *matched_ref = matched;
 998                 return match;
 999         }
1000 }
1001
1002 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1003 {
1004         **tail = ref;
1005         while (ref->next)
1006                 ref = ref->next;
1007         *tail = &ref->next;
1008 }
1009
1010 static struct ref *try_explicit_object_name(const char *name)
1011 {
1012         unsigned char sha1[20];
1013         struct ref *ref;
1014
1015         if (!*name) {
1016                 ref = alloc_ref("(delete)");
1017                 hashclr(ref->new_sha1);
1018                 return ref;
1019         }
1020         if (get_sha1(name, sha1))
1021                 return NULL;
1022         ref = alloc_ref(name);
1023         hashcpy(ref->new_sha1, sha1);
1024         return ref;
1025 }
1026
1027 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1028 {
1029         struct ref *ret = alloc_ref(name);
1030         tail_link_ref(ret, tail);
1031         return ret;
1032 }
1033
1034 static char *guess_ref(const char *name, struct ref *peer)
1035 {
1036         struct strbuf buf = STRBUF_INIT;
1037         unsigned char sha1[20];
1038
1039         const char *r = resolve_ref(peer->name, sha1, 1, NULL);
1040         if (!r)
1041                 return NULL;
1042
1043         if (!prefixcmp(r, "refs/heads/"))
1044                 strbuf_addstr(&buf, "refs/heads/");
1045         else if (!prefixcmp(r, "refs/tags/"))
1046                 strbuf_addstr(&buf, "refs/tags/");
1047         else
1048                 return NULL;
1049
1050         strbuf_addstr(&buf, name);
1051         return strbuf_detach(&buf, NULL);
1052 }
1053
1054 static int match_explicit(struct ref *src, struct ref *dst,
1055                           struct ref ***dst_tail,
1056                           struct refspec *rs)
1057 {
1058         struct ref *matched_src, *matched_dst;
1059         int copy_src;
1060
1061         const char *dst_value = rs->dst;
1062         char *dst_guess;
1063
1064         if (rs->pattern || rs->matching)
1065                 return 0;
1066
1067         matched_src = matched_dst = NULL;
1068         switch (count_refspec_match(rs->src, src, &matched_src)) {
1069         case 1:
1070                 copy_src = 1;
1071                 break;
1072         case 0:
1073                 /* The source could be in the get_sha1() format
1074                  * not a reference name.  :refs/other is a
1075                  * way to delete 'other' ref at the remote end.
1076                  */
1077                 matched_src = try_explicit_object_name(rs->src);
1078                 if (!matched_src)
1079                         return error("src refspec %s does not match any.", rs->src);
1080                 copy_src = 0;
1081                 break;
1082         default:
1083                 return error("src refspec %s matches more than one.", rs->src);
1084         }
1085
1086         if (!dst_value) {
1087                 unsigned char sha1[20];
1088                 int flag;
1089
1090                 dst_value = resolve_ref(matched_src->name, sha1, 1, &flag);
1091                 if (!dst_value ||
1092                     ((flag & REF_ISSYMREF) &&
1093                      prefixcmp(dst_value, "refs/heads/")))
1094                         die("%s cannot be resolved to branch.",
1095                             matched_src->name);
1096         }
1097
1098         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1099         case 1:
1100                 break;
1101         case 0:
1102                 if (!memcmp(dst_value, "refs/", 5))
1103                         matched_dst = make_linked_ref(dst_value, dst_tail);
1104                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1105                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1106                 else
1107                         error("unable to push to unqualified destination: %s\n"
1108                               "The destination refspec neither matches an "
1109                               "existing ref on the remote nor\n"
1110                               "begins with refs/, and we are unable to "
1111                               "guess a prefix based on the source ref.",
1112                               dst_value);
1113                 break;
1114         default:
1115                 matched_dst = NULL;
1116                 error("dst refspec %s matches more than one.",
1117                       dst_value);
1118                 break;
1119         }
1120         if (!matched_dst)
1121                 return -1;
1122         if (matched_dst->peer_ref)
1123                 return error("dst ref %s receives from more than one src.",
1124                       matched_dst->name);
1125         else {
1126                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1127                 matched_dst->force = rs->force;
1128         }
1129         return 0;
1130 }
1131
1132 static int match_explicit_refs(struct ref *src, struct ref *dst,
1133                                struct ref ***dst_tail, struct refspec *rs,
1134                                int rs_nr)
1135 {
1136         int i, errs;
1137         for (i = errs = 0; i < rs_nr; i++)
1138                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1139         return errs;
1140 }
1141
1142 static const struct refspec *check_pattern_match(const struct refspec *rs,
1143                                                  int rs_nr,
1144                                                  const struct ref *src)
1145 {
1146         int i;
1147         int matching_refs = -1;
1148         for (i = 0; i < rs_nr; i++) {
1149                 if (rs[i].matching &&
1150                     (matching_refs == -1 || rs[i].force)) {
1151                         matching_refs = i;
1152                         continue;
1153                 }
1154
1155                 if (rs[i].pattern && match_name_with_pattern(rs[i].src, src->name,
1156                                                              NULL, NULL))
1157                         return rs + i;
1158         }
1159         if (matching_refs != -1)
1160                 return rs + matching_refs;
1161         else
1162                 return NULL;
1163 }
1164
1165 static struct ref **tail_ref(struct ref **head)
1166 {
1167         struct ref **tail = head;
1168         while (*tail)
1169                 tail = &((*tail)->next);
1170         return tail;
1171 }
1172
1173 /*
1174  * Note. This is used only by "push"; refspec matching rules for
1175  * push and fetch are subtly different, so do not try to reuse it
1176  * without thinking.
1177  */
1178 int match_refs(struct ref *src, struct ref **dst,
1179                int nr_refspec, const char **refspec, int flags)
1180 {
1181         struct refspec *rs;
1182         int send_all = flags & MATCH_REFS_ALL;
1183         int send_mirror = flags & MATCH_REFS_MIRROR;
1184         int errs;
1185         static const char *default_refspec[] = { ":", NULL };
1186         struct ref **dst_tail = tail_ref(dst);
1187
1188         if (!nr_refspec) {
1189                 nr_refspec = 1;
1190                 refspec = default_refspec;
1191         }
1192         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1193         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1194
1195         /* pick the remainder */
1196         for ( ; src; src = src->next) {
1197                 struct ref *dst_peer;
1198                 const struct refspec *pat = NULL;
1199                 char *dst_name;
1200                 if (src->peer_ref)
1201                         continue;
1202
1203                 pat = check_pattern_match(rs, nr_refspec, src);
1204                 if (!pat)
1205                         continue;
1206
1207                 if (pat->matching) {
1208                         /*
1209                          * "matching refs"; traditionally we pushed everything
1210                          * including refs outside refs/heads/ hierarchy, but
1211                          * that does not make much sense these days.
1212                          */
1213                         if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
1214                                 continue;
1215                         dst_name = xstrdup(src->name);
1216
1217                 } else {
1218                         const char *dst_side = pat->dst ? pat->dst : pat->src;
1219                         if (!match_name_with_pattern(pat->src, src->name,
1220                                                      dst_side, &dst_name))
1221                                 die("Didn't think it matches any more");
1222                 }
1223                 dst_peer = find_ref_by_name(*dst, dst_name);
1224                 if (dst_peer) {
1225                         if (dst_peer->peer_ref)
1226                                 /* We're already sending something to this ref. */
1227                                 goto free_name;
1228
1229                 } else {
1230                         if (pat->matching && !(send_all || send_mirror))
1231                                 /*
1232                                  * Remote doesn't have it, and we have no
1233                                  * explicit pattern, and we don't have
1234                                  * --all nor --mirror.
1235                                  */
1236                                 goto free_name;
1237
1238                         /* Create a new one and link it */
1239                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1240                         hashcpy(dst_peer->new_sha1, src->new_sha1);
1241                 }
1242                 dst_peer->peer_ref = copy_ref(src);
1243                 dst_peer->force = pat->force;
1244         free_name:
1245                 free(dst_name);
1246         }
1247         if (errs)
1248                 return -1;
1249         return 0;
1250 }
1251
1252 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1253         int force_update)
1254 {
1255         struct ref *ref;
1256
1257         for (ref = remote_refs; ref; ref = ref->next) {
1258                 if (ref->peer_ref)
1259                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1260                 else if (!send_mirror)
1261                         continue;
1262
1263                 ref->deletion = is_null_sha1(ref->new_sha1);
1264                 if (!ref->deletion &&
1265                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1266                         ref->status = REF_STATUS_UPTODATE;
1267                         continue;
1268                 }
1269
1270                 /* This part determines what can overwrite what.
1271                  * The rules are:
1272                  *
1273                  * (0) you can always use --force or +A:B notation to
1274                  *     selectively force individual ref pairs.
1275                  *
1276                  * (1) if the old thing does not exist, it is OK.
1277                  *
1278                  * (2) if you do not have the old thing, you are not allowed
1279                  *     to overwrite it; you would not know what you are losing
1280                  *     otherwise.
1281                  *
1282                  * (3) if both new and old are commit-ish, and new is a
1283                  *     descendant of old, it is OK.
1284                  *
1285                  * (4) regardless of all of the above, removing :B is
1286                  *     always allowed.
1287                  */
1288
1289                 ref->nonfastforward =
1290                         !ref->deletion &&
1291                         !is_null_sha1(ref->old_sha1) &&
1292                         (!has_sha1_file(ref->old_sha1)
1293                           || !ref_newer(ref->new_sha1, ref->old_sha1));
1294
1295                 if (ref->nonfastforward && !ref->force && !force_update) {
1296                         ref->status = REF_STATUS_REJECT_NONFASTFORWARD;
1297                         continue;
1298                 }
1299         }
1300 }
1301
1302 struct branch *branch_get(const char *name)
1303 {
1304         struct branch *ret;
1305
1306         read_config();
1307         if (!name || !*name || !strcmp(name, "HEAD"))
1308                 ret = current_branch;
1309         else
1310                 ret = make_branch(name, 0);
1311         if (ret && ret->remote_name) {
1312                 ret->remote = remote_get(ret->remote_name);
1313                 if (ret->merge_nr) {
1314                         int i;
1315                         ret->merge = xcalloc(sizeof(*ret->merge),
1316                                              ret->merge_nr);
1317                         for (i = 0; i < ret->merge_nr; i++) {
1318                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1319                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1320                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1321                                     && !strcmp(ret->remote_name, "."))
1322                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1323                         }
1324                 }
1325         }
1326         return ret;
1327 }
1328
1329 int branch_has_merge_config(struct branch *branch)
1330 {
1331         return branch && !!branch->merge;
1332 }
1333
1334 int branch_merge_matches(struct branch *branch,
1335                                  int i,
1336                                  const char *refname)
1337 {
1338         if (!branch || i < 0 || i >= branch->merge_nr)
1339                 return 0;
1340         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1341 }
1342
1343 static struct ref *get_expanded_map(const struct ref *remote_refs,
1344                                     const struct refspec *refspec)
1345 {
1346         const struct ref *ref;
1347         struct ref *ret = NULL;
1348         struct ref **tail = &ret;
1349
1350         char *expn_name;
1351
1352         for (ref = remote_refs; ref; ref = ref->next) {
1353                 if (strchr(ref->name, '^'))
1354                         continue; /* a dereference item */
1355                 if (match_name_with_pattern(refspec->src, ref->name,
1356                                             refspec->dst, &expn_name)) {
1357                         struct ref *cpy = copy_ref(ref);
1358
1359                         cpy->peer_ref = alloc_ref(expn_name);
1360                         free(expn_name);
1361                         if (refspec->force)
1362                                 cpy->peer_ref->force = 1;
1363                         *tail = cpy;
1364                         tail = &cpy->next;
1365                 }
1366         }
1367
1368         return ret;
1369 }
1370
1371 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1372 {
1373         const struct ref *ref;
1374         for (ref = refs; ref; ref = ref->next) {
1375                 if (refname_match(name, ref->name, ref_fetch_rules))
1376                         return ref;
1377         }
1378         return NULL;
1379 }
1380
1381 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1382 {
1383         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1384
1385         if (!ref)
1386                 return NULL;
1387
1388         return copy_ref(ref);
1389 }
1390
1391 static struct ref *get_local_ref(const char *name)
1392 {
1393         if (!name || name[0] == '\0')
1394                 return NULL;
1395
1396         if (!prefixcmp(name, "refs/"))
1397                 return alloc_ref(name);
1398
1399         if (!prefixcmp(name, "heads/") ||
1400             !prefixcmp(name, "tags/") ||
1401             !prefixcmp(name, "remotes/"))
1402                 return alloc_ref_with_prefix("refs/", 5, name);
1403
1404         return alloc_ref_with_prefix("refs/heads/", 11, name);
1405 }
1406
1407 int get_fetch_map(const struct ref *remote_refs,
1408                   const struct refspec *refspec,
1409                   struct ref ***tail,
1410                   int missing_ok)
1411 {
1412         struct ref *ref_map, **rmp;
1413
1414         if (refspec->pattern) {
1415                 ref_map = get_expanded_map(remote_refs, refspec);
1416         } else {
1417                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1418
1419                 ref_map = get_remote_ref(remote_refs, name);
1420                 if (!missing_ok && !ref_map)
1421                         die("Couldn't find remote ref %s", name);
1422                 if (ref_map) {
1423                         ref_map->peer_ref = get_local_ref(refspec->dst);
1424                         if (ref_map->peer_ref && refspec->force)
1425                                 ref_map->peer_ref->force = 1;
1426                 }
1427         }
1428
1429         for (rmp = &ref_map; *rmp; ) {
1430                 if ((*rmp)->peer_ref) {
1431                         int st = check_ref_format((*rmp)->peer_ref->name + 5);
1432                         if (st && st != CHECK_REF_FORMAT_ONELEVEL) {
1433                                 struct ref *ignore = *rmp;
1434                                 error("* Ignoring funny ref '%s' locally",
1435                                       (*rmp)->peer_ref->name);
1436                                 *rmp = (*rmp)->next;
1437                                 free(ignore->peer_ref);
1438                                 free(ignore);
1439                                 continue;
1440                         }
1441                 }
1442                 rmp = &((*rmp)->next);
1443         }
1444
1445         if (ref_map)
1446                 tail_link_ref(ref_map, tail);
1447
1448         return 0;
1449 }
1450
1451 int resolve_remote_symref(struct ref *ref, struct ref *list)
1452 {
1453         if (!ref->symref)
1454                 return 0;
1455         for (; list; list = list->next)
1456                 if (!strcmp(ref->symref, list->name)) {
1457                         hashcpy(ref->old_sha1, list->old_sha1);
1458                         return 0;
1459                 }
1460         return 1;
1461 }
1462
1463 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1464 {
1465         while (list) {
1466                 struct commit_list *temp = list;
1467                 temp->item->object.flags &= ~mark;
1468                 list = temp->next;
1469                 free(temp);
1470         }
1471 }
1472
1473 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1474 {
1475         struct object *o;
1476         struct commit *old, *new;
1477         struct commit_list *list, *used;
1478         int found = 0;
1479
1480         /* Both new and old must be commit-ish and new is descendant of
1481          * old.  Otherwise we require --force.
1482          */
1483         o = deref_tag(parse_object(old_sha1), NULL, 0);
1484         if (!o || o->type != OBJ_COMMIT)
1485                 return 0;
1486         old = (struct commit *) o;
1487
1488         o = deref_tag(parse_object(new_sha1), NULL, 0);
1489         if (!o || o->type != OBJ_COMMIT)
1490                 return 0;
1491         new = (struct commit *) o;
1492
1493         if (parse_commit(new) < 0)
1494                 return 0;
1495
1496         used = list = NULL;
1497         commit_list_insert(new, &list);
1498         while (list) {
1499                 new = pop_most_recent_commit(&list, TMP_MARK);
1500                 commit_list_insert(new, &used);
1501                 if (new == old) {
1502                         found = 1;
1503                         break;
1504                 }
1505         }
1506         unmark_and_free(list, TMP_MARK);
1507         unmark_and_free(used, TMP_MARK);
1508         return found;
1509 }
1510
1511 /*
1512  * Return true if there is anything to report, otherwise false.
1513  */
1514 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1515 {
1516         unsigned char sha1[20];
1517         struct commit *ours, *theirs;
1518         char symmetric[84];
1519         struct rev_info revs;
1520         const char *rev_argv[10], *base;
1521         int rev_argc;
1522
1523         /*
1524          * Nothing to report unless we are marked to build on top of
1525          * somebody else.
1526          */
1527         if (!branch ||
1528             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1529                 return 0;
1530
1531         /*
1532          * If what we used to build on no longer exists, there is
1533          * nothing to report.
1534          */
1535         base = branch->merge[0]->dst;
1536         if (!resolve_ref(base, sha1, 1, NULL))
1537                 return 0;
1538         theirs = lookup_commit_reference(sha1);
1539         if (!theirs)
1540                 return 0;
1541
1542         if (!resolve_ref(branch->refname, sha1, 1, NULL))
1543                 return 0;
1544         ours = lookup_commit_reference(sha1);
1545         if (!ours)
1546                 return 0;
1547
1548         /* are we the same? */
1549         if (theirs == ours)
1550                 return 0;
1551
1552         /* Run "rev-list --left-right ours...theirs" internally... */
1553         rev_argc = 0;
1554         rev_argv[rev_argc++] = NULL;
1555         rev_argv[rev_argc++] = "--left-right";
1556         rev_argv[rev_argc++] = symmetric;
1557         rev_argv[rev_argc++] = "--";
1558         rev_argv[rev_argc] = NULL;
1559
1560         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1561         strcpy(symmetric + 40, "...");
1562         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1563
1564         init_revisions(&revs, NULL);
1565         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1566         prepare_revision_walk(&revs);
1567
1568         /* ... and count the commits on each side. */
1569         *num_ours = 0;
1570         *num_theirs = 0;
1571         while (1) {
1572                 struct commit *c = get_revision(&revs);
1573                 if (!c)
1574                         break;
1575                 if (c->object.flags & SYMMETRIC_LEFT)
1576                         (*num_ours)++;
1577                 else
1578                         (*num_theirs)++;
1579         }
1580
1581         /* clear object flags smudged by the above traversal */
1582         clear_commit_marks(ours, ALL_REV_FLAGS);
1583         clear_commit_marks(theirs, ALL_REV_FLAGS);
1584         return 1;
1585 }
1586
1587 /*
1588  * Return true when there is anything to report, otherwise false.
1589  */
1590 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1591 {
1592         int num_ours, num_theirs;
1593         const char *base;
1594
1595         if (!stat_tracking_info(branch, &num_ours, &num_theirs))
1596                 return 0;
1597
1598         base = branch->merge[0]->dst;
1599         base = shorten_unambiguous_ref(base, 0);
1600         if (!num_theirs)
1601                 strbuf_addf(sb, "Your branch is ahead of '%s' "
1602                             "by %d commit%s.\n",
1603                             base, num_ours, (num_ours == 1) ? "" : "s");
1604         else if (!num_ours)
1605                 strbuf_addf(sb, "Your branch is behind '%s' "
1606                             "by %d commit%s, "
1607                             "and can be fast-forwarded.\n",
1608                             base, num_theirs, (num_theirs == 1) ? "" : "s");
1609         else
1610                 strbuf_addf(sb, "Your branch and '%s' have diverged,\n"
1611                             "and have %d and %d different commit(s) each, "
1612                             "respectively.\n",
1613                             base, num_ours, num_theirs);
1614         return 1;
1615 }
1616
1617 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1618 {
1619         struct ref ***local_tail = cb_data;
1620         struct ref *ref;
1621         int len;
1622
1623         /* we already know it starts with refs/ to get here */
1624         if (check_ref_format(refname + 5))
1625                 return 0;
1626
1627         len = strlen(refname) + 1;
1628         ref = xcalloc(1, sizeof(*ref) + len);
1629         hashcpy(ref->new_sha1, sha1);
1630         memcpy(ref->name, refname, len);
1631         **local_tail = ref;
1632         *local_tail = &ref->next;
1633         return 0;
1634 }
1635
1636 struct ref *get_local_heads(void)
1637 {
1638         struct ref *local_refs = NULL, **local_tail = &local_refs;
1639         for_each_ref(one_local_ref, &local_tail);
1640         return local_refs;
1641 }
1642
1643 struct ref *guess_remote_head(const struct ref *head,
1644                               const struct ref *refs,
1645                               int all)
1646 {
1647         const struct ref *r;
1648         struct ref *list = NULL;
1649         struct ref **tail = &list;
1650
1651         if (!head)
1652                 return NULL;
1653
1654         /*
1655          * Some transports support directly peeking at
1656          * where HEAD points; if that is the case, then
1657          * we don't have to guess.
1658          */
1659         if (head->symref)
1660                 return copy_ref(find_ref_by_name(refs, head->symref));
1661
1662         /* If refs/heads/master could be right, it is. */
1663         if (!all) {
1664                 r = find_ref_by_name(refs, "refs/heads/master");
1665                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1666                         return copy_ref(r);
1667         }
1668
1669         /* Look for another ref that points there */
1670         for (r = refs; r; r = r->next) {
1671                 if (r != head && !hashcmp(r->old_sha1, head->old_sha1)) {
1672                         *tail = copy_ref(r);
1673                         tail = &((*tail)->next);
1674                         if (!all)
1675                                 break;
1676                 }
1677         }
1678
1679         return list;
1680 }
1681
1682 struct stale_heads_info {
1683         struct remote *remote;
1684         struct string_list *ref_names;
1685         struct ref **stale_refs_tail;
1686 };
1687
1688 static int get_stale_heads_cb(const char *refname,
1689         const unsigned char *sha1, int flags, void *cb_data)
1690 {
1691         struct stale_heads_info *info = cb_data;
1692         struct refspec refspec;
1693         memset(&refspec, 0, sizeof(refspec));
1694         refspec.dst = (char *)refname;
1695         if (!remote_find_tracking(info->remote, &refspec)) {
1696                 if (!((flags & REF_ISSYMREF) ||
1697                     string_list_has_string(info->ref_names, refspec.src))) {
1698                         struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
1699                         hashcpy(ref->new_sha1, sha1);
1700                 }
1701         }
1702         return 0;
1703 }
1704
1705 struct ref *get_stale_heads(struct remote *remote, struct ref *fetch_map)
1706 {
1707         struct ref *ref, *stale_refs = NULL;
1708         struct string_list ref_names = { NULL, 0, 0, 0 };
1709         struct stale_heads_info info;
1710         info.remote = remote;
1711         info.ref_names = &ref_names;
1712         info.stale_refs_tail = &stale_refs;
1713         for (ref = fetch_map; ref; ref = ref->next)
1714                 string_list_append(ref->name, &ref_names);
1715         sort_string_list(&ref_names);
1716         for_each_ref(get_stale_heads_cb, &info);
1717         string_list_clear(&ref_names, 0);
1718         return stale_refs;
1719 }