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(subkey, ".proxy")) {
 447                 return git_config_string((const char **)&remote->http_proxy,
 448                                          key, value);
 449         } else if (!strcmp(subkey, ".vcs")) {
 450                 return git_config_string(&remote->foreign_vcs, key, value);
 451         }
 452         return 0;
 453 }
 454
 455 static void alias_all_urls(void)
 456 {
 457         int i, j;
 458         for (i = 0; i < remotes_nr; i++) {
 459                 int add_pushurl_aliases;
 460                 if (!remotes[i])
 461                         continue;
 462                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 463                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 464                 }
 465                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 466                 for (j = 0; j < remotes[i]->url_nr; j++) {
 467                         if (add_pushurl_aliases)
 468                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 469                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 470                 }
 471         }
 472 }
 473
 474 static void read_config(void)
 475 {
 476         unsigned char sha1[20];
 477         const char *head_ref;
 478         int flag;
 479         if (default_remote_name) // did this already
 480                 return;
 481         default_remote_name = xstrdup("origin");
 482         current_branch = NULL;
 483         head_ref = resolve_ref("HEAD", sha1, 0, &flag);
 484         if (head_ref && (flag & REF_ISSYMREF) &&
 485             !prefixcmp(head_ref, "refs/heads/")) {
 486                 current_branch =
 487                         make_branch(head_ref + strlen("refs/heads/"), 0);
 488         }
 489         git_config(handle_config, NULL);
 490         alias_all_urls();
 491 }
 492
 493 /*
 494  * We need to make sure the tracking branches are well formed, but a
 495  * wildcard refspec in "struct refspec" must have a trailing slash. We
 496  * temporarily drop the trailing '/' while calling check_ref_format(),
 497  * and put it back.  The caller knows that a CHECK_REF_FORMAT_ONELEVEL
 498  * error return is Ok for a wildcard refspec.
 499  */
 500 static int verify_refname(char *name, int is_glob)
 501 {
 502         int result;
 503
 504         result = check_ref_format(name);
 505         if (is_glob && result == CHECK_REF_FORMAT_WILDCARD)
 506                 result = CHECK_REF_FORMAT_OK;
 507         return result;
 508 }
 509
 510 /*
 511  * This function frees a refspec array.
 512  * Warning: code paths should be checked to ensure that the src
 513  *          and dst pointers are always freeable pointers as well
 514  *          as the refspec pointer itself.
 515  */
 516 static void free_refspecs(struct refspec *refspec, int nr_refspec)
 517 {
 518         int i;
 519
 520         if (!refspec)
 521                 return;
 522
 523         for (i = 0; i < nr_refspec; i++) {
 524                 free(refspec[i].src);
 525                 free(refspec[i].dst);
 526         }
 527         free(refspec);
 528 }
 529
 530 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 531 {
 532         int i;
 533         int st;
 534         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 535
 536         for (i = 0; i < nr_refspec; i++) {
 537                 size_t llen;
 538                 int is_glob;
 539                 const char *lhs, *rhs;
 540
 541                 is_glob = 0;
 542
 543                 lhs = refspec[i];
 544                 if (*lhs == '+') {
 545                         rs[i].force = 1;
 546                         lhs++;
 547                 }
 548
 549                 rhs = strrchr(lhs, ':');
 550
 551                 /*
 552                  * Before going on, special case ":" (or "+:") as a refspec
 553                  * for matching refs.
 554                  */
 555                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
 556                         rs[i].matching = 1;
 557                         continue;
 558                 }
 559
 560                 if (rhs) {
 561                         size_t rlen = strlen(++rhs);
 562                         is_glob = (1 <= rlen && strchr(rhs, '*'));
 563                         rs[i].dst = xstrndup(rhs, rlen);
 564                 }
 565
 566                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 567                 if (1 <= llen && memchr(lhs, '*', llen)) {
 568                         if ((rhs && !is_glob) || (!rhs && fetch))
 569                                 goto invalid;
 570                         is_glob = 1;
 571                 } else if (rhs && is_glob) {
 572                         goto invalid;
 573                 }
 574
 575                 rs[i].pattern = is_glob;
 576                 rs[i].src = xstrndup(lhs, llen);
 577
 578                 if (fetch) {
 579                         /*
 580                          * LHS
 581                          * - empty is allowed; it means HEAD.
 582                          * - otherwise it must be a valid looking ref.
 583                          */
 584                         if (!*rs[i].src)
 585                                 ; /* empty is ok */
 586                         else {
 587                                 st = verify_refname(rs[i].src, is_glob);
 588                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 589                                         goto invalid;
 590                         }
 591                         /*
 592                          * RHS
 593                          * - missing is ok, and is same as empty.
 594                          * - empty is ok; it means not to store.
 595                          * - otherwise it must be a valid looking ref.
 596                          */
 597                         if (!rs[i].dst) {
 598                                 ; /* ok */
 599                         } else if (!*rs[i].dst) {
 600                                 ; /* ok */
 601                         } else {
 602                                 st = verify_refname(rs[i].dst, is_glob);
 603                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 604                                         goto invalid;
 605                         }
 606                 } else {
 607                         /*
 608                          * LHS
 609                          * - empty is allowed; it means delete.
 610                          * - when wildcarded, it must be a valid looking ref.
 611                          * - otherwise, it must be an extended SHA-1, but
 612                          *   there is no existing way to validate this.
 613                          */
 614                         if (!*rs[i].src)
 615                                 ; /* empty is ok */
 616                         else if (is_glob) {
 617                                 st = verify_refname(rs[i].src, is_glob);
 618                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 619                                         goto invalid;
 620                         }
 621                         else
 622                                 ; /* anything goes, for now */
 623                         /*
 624                          * RHS
 625                          * - missing is allowed, but LHS then must be a
 626                          *   valid looking ref.
 627                          * - empty is not allowed.
 628                          * - otherwise it must be a valid looking ref.
 629                          */
 630                         if (!rs[i].dst) {
 631                                 st = verify_refname(rs[i].src, is_glob);
 632                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 633                                         goto invalid;
 634                         } else if (!*rs[i].dst) {
 635                                 goto invalid;
 636                         } else {
 637                                 st = verify_refname(rs[i].dst, is_glob);
 638                                 if (st && st != CHECK_REF_FORMAT_ONELEVEL)
 639                                         goto invalid;
 640                         }
 641                 }
 642         }
 643         return rs;
 644
 645  invalid:
 646         if (verify) {
 647                 /*
 648                  * nr_refspec must be greater than zero and i must be valid
 649                  * since it is only possible to reach this point from within
 650                  * the for loop above.
 651                  */
 652                 free_refspecs(rs, i+1);
 653                 return NULL;
 654         }
 655         die("Invalid refspec '%s'", refspec[i]);
 656 }
 657
 658 int valid_fetch_refspec(const char *fetch_refspec_str)
 659 {
 660         struct refspec *refspec;
 661
 662         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
 663         free_refspecs(refspec, 1);
 664         return !!refspec;
 665 }
 666
 667 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 668 {
 669         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 670 }
 671
 672 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 673 {
 674         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 675 }
 676
 677 void free_refspec(int nr_refspec, struct refspec *refspec)
 678 {
 679         int i;
 680         for (i = 0; i < nr_refspec; i++) {
 681                 free(refspec[i].src);
 682                 free(refspec[i].dst);
 683         }
 684         free(refspec);
 685 }
 686
 687 static int valid_remote_nick(const char *name)
 688 {
 689         if (!name[0] || is_dot_or_dotdot(name))
 690                 return 0;
 691         return !strchr(name, '/'); /* no slash */
 692 }
 693
 694 struct remote *remote_get(const char *name)
 695 {
 696         struct remote *ret;
 697         int name_given = 0;
 698
 699         read_config();
 700         if (name)
 701                 name_given = 1;
 702         else {
 703                 name = default_remote_name;
 704                 name_given = explicit_default_remote_name;
 705         }
 706
 707         ret = make_remote(name, 0);
 708         if (valid_remote_nick(name)) {
 709                 if (!valid_remote(ret))
 710                         read_remotes_file(ret);
 711                 if (!valid_remote(ret))
 712                         read_branches_file(ret);
 713         }
 714         if (name_given && !valid_remote(ret))
 715                 add_url_alias(ret, name);
 716         if (!valid_remote(ret))
 717                 return NULL;
 718         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 719         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 720         return ret;
 721 }
 722
 723 int remote_is_configured(const char *name)
 724 {
 725         int i;
 726         read_config();
 727
 728         for (i = 0; i < remotes_nr; i++)
 729                 if (!strcmp(name, remotes[i]->name))
 730                         return 1;
 731         return 0;
 732 }
 733
 734 int for_each_remote(each_remote_fn fn, void *priv)
 735 {
 736         int i, result = 0;
 737         read_config();
 738         for (i = 0; i < remotes_nr && !result; i++) {
 739                 struct remote *r = remotes[i];
 740                 if (!r)
 741                         continue;
 742                 if (!r->fetch)
 743                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 744                                                        r->fetch_refspec);
 745                 if (!r->push)
 746                         r->push = parse_push_refspec(r->push_refspec_nr,
 747                                                      r->push_refspec);
 748                 result = fn(r, priv);
 749         }
 750         return result;
 751 }
 752
 753 void ref_remove_duplicates(struct ref *ref_map)
 754 {
 755         struct string_list refs = { NULL, 0, 0, 0 };
 756         struct string_list_item *item = NULL;
 757         struct ref *prev = NULL, *next = NULL;
 758         for (; ref_map; prev = ref_map, ref_map = next) {
 759                 next = ref_map->next;
 760                 if (!ref_map->peer_ref)
 761                         continue;
 762
 763                 item = string_list_lookup(ref_map->peer_ref->name, &refs);
 764                 if (item) {
 765                         if (strcmp(((struct ref *)item->util)->name,
 766                                    ref_map->name))
 767                                 die("%s tracks both %s and %s",
 768                                     ref_map->peer_ref->name,
 769                                     ((struct ref *)item->util)->name,
 770                                     ref_map->name);
 771                         prev->next = ref_map->next;
 772                         free(ref_map->peer_ref);
 773                         free(ref_map);
 774                         ref_map = prev; /* skip this; we freed it */
 775                         continue;
 776                 }
 777
 778                 item = string_list_insert(ref_map->peer_ref->name, &refs);
 779                 item->util = ref_map;
 780         }
 781         string_list_clear(&refs, 0);
 782 }
 783
 784 int remote_has_url(struct remote *remote, const char *url)
 785 {
 786         int i;
 787         for (i = 0; i < remote->url_nr; i++) {
 788                 if (!strcmp(remote->url[i], url))
 789                         return 1;
 790         }
 791         return 0;
 792 }
 793
 794 static int match_name_with_pattern(const char *key, const char *name,
 795                                    const char *value, char **result)
 796 {
 797         const char *kstar = strchr(key, '*');
 798         size_t klen;
 799         size_t ksuffixlen;
 800         size_t namelen;
 801         int ret;
 802         if (!kstar)
 803                 die("Key '%s' of pattern had no '*'", key);
 804         klen = kstar - key;
 805         ksuffixlen = strlen(kstar + 1);
 806         namelen = strlen(name);
 807         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 808                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 809         if (ret && value) {
 810                 const char *vstar = strchr(value, '*');
 811                 size_t vlen;
 812                 size_t vsuffixlen;
 813                 if (!vstar)
 814                         die("Value '%s' of pattern has no '*'", value);
 815                 vlen = vstar - value;
 816                 vsuffixlen = strlen(vstar + 1);
 817                 *result = xmalloc(vlen + vsuffixlen +
 818                                   strlen(name) -
 819                                   klen - ksuffixlen + 1);
 820                 strncpy(*result, value, vlen);
 821                 strncpy(*result + vlen,
 822                         name + klen, namelen - klen - ksuffixlen);
 823                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
 824                        vstar + 1);
 825         }
 826         return ret;
 827 }
 828
 829 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 830                      const char *name)
 831 {
 832         int i;
 833         char *ret = NULL;
 834         for (i = 0; i < nr_refspec; i++) {
 835                 struct refspec *refspec = refspecs + i;
 836                 if (refspec->pattern) {
 837                         if (match_name_with_pattern(refspec->src, name,
 838                                                     refspec->dst, &ret))
 839                                 return ret;
 840                 } else if (!strcmp(refspec->src, name))
 841                         return strdup(refspec->dst);
 842         }
 843         return NULL;
 844 }
 845
 846 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 847 {
 848         int find_src = refspec->src == NULL;
 849         char *needle, **result;
 850         int i;
 851
 852         if (find_src) {
 853                 if (!refspec->dst)
 854                         return error("find_tracking: need either src or dst");
 855                 needle = refspec->dst;
 856                 result = &refspec->src;
 857         } else {
 858                 needle = refspec->src;
 859                 result = &refspec->dst;
 860         }
 861
 862         for (i = 0; i < remote->fetch_refspec_nr; i++) {
 863                 struct refspec *fetch = &remote->fetch[i];
 864                 const char *key = find_src ? fetch->dst : fetch->src;
 865                 const char *value = find_src ? fetch->src : fetch->dst;
 866                 if (!fetch->dst)
 867                         continue;
 868                 if (fetch->pattern) {
 869                         if (match_name_with_pattern(key, needle, value, result)) {
 870                                 refspec->force = fetch->force;
 871                                 return 0;
 872                         }
 873                 } else if (!strcmp(needle, key)) {
 874                         *result = xstrdup(value);
 875                         refspec->force = fetch->force;
 876                         return 0;
 877                 }
 878         }
 879         return -1;
 880 }
 881
 882 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 883                 const char *name)
 884 {
 885         size_t len = strlen(name);
 886         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 887         memcpy(ref->name, prefix, prefixlen);
 888         memcpy(ref->name + prefixlen, name, len);
 889         return ref;
 890 }
 891
 892 struct ref *alloc_ref(const char *name)
 893 {
 894         return alloc_ref_with_prefix("", 0, name);
 895 }
 896
 897 static struct ref *copy_ref(const struct ref *ref)
 898 {
 899         struct ref *cpy;
 900         size_t len;
 901         if (!ref)
 902                 return NULL;
 903         len = strlen(ref->name);
 904         cpy = xmalloc(sizeof(struct ref) + len + 1);
 905         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 906         cpy->next = NULL;
 907         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 908         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 909         cpy->peer_ref = copy_ref(ref->peer_ref);
 910         return cpy;
 911 }
 912
 913 struct ref *copy_ref_list(const struct ref *ref)
 914 {
 915         struct ref *ret = NULL;
 916         struct ref **tail = &ret;
 917         while (ref) {
 918                 *tail = copy_ref(ref);
 919                 ref = ref->next;
 920                 tail = &((*tail)->next);
 921         }
 922         return ret;
 923 }
 924
 925 static void free_ref(struct ref *ref)
 926 {
 927         if (!ref)
 928                 return;
 929         free_ref(ref->peer_ref);
 930         free(ref->remote_status);
 931         free(ref->symref);
 932         free(ref);
 933 }
 934
 935 void free_refs(struct ref *ref)
 936 {
 937         struct ref *next;
 938         while (ref) {
 939                 next = ref->next;
 940                 free_ref(ref);
 941                 ref = next;
 942         }
 943 }
 944
 945 static int count_refspec_match(const char *pattern,
 946                                struct ref *refs,
 947                                struct ref **matched_ref)
 948 {
 949         int patlen = strlen(pattern);
 950         struct ref *matched_weak = NULL;
 951         struct ref *matched = NULL;
 952         int weak_match = 0;
 953         int match = 0;
 954
 955         for (weak_match = match = 0; refs; refs = refs->next) {
 956                 char *name = refs->name;
 957                 int namelen = strlen(name);
 958
 959                 if (!refname_match(pattern, name, ref_rev_parse_rules))
 960                         continue;
 961
 962                 /* A match is "weak" if it is with refs outside
 963                  * heads or tags, and did not specify the pattern
 964                  * in full (e.g. "refs/remotes/origin/master") or at
 965                  * least from the toplevel (e.g. "remotes/origin/master");
 966                  * otherwise "git push $URL master" would result in
 967                  * ambiguity between remotes/origin/master and heads/master
 968                  * at the remote site.
 969                  */
 970                 if (namelen != patlen &&
 971                     patlen != namelen - 5 &&
 972                     prefixcmp(name, "refs/heads/") &&
 973                     prefixcmp(name, "refs/tags/")) {
 974                         /* We want to catch the case where only weak
 975                          * matches are found and there are multiple
 976                          * matches, and where more than one strong
 977                          * matches are found, as ambiguous.  One
 978                          * strong match with zero or more weak matches
 979                          * are acceptable as a unique match.
 980                          */
 981                         matched_weak = refs;
 982                         weak_match++;
 983                 }
 984                 else {
 985                         matched = refs;
 986                         match++;
 987                 }
 988         }
 989         if (!matched) {
 990                 *matched_ref = matched_weak;
 991                 return weak_match;
 992         }
 993         else {
 994                 *matched_ref = matched;
 995                 return match;
 996         }
 997 }
 998
 999 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1000 {
1001         **tail = ref;
1002         while (ref->next)
1003                 ref = ref->next;
1004         *tail = &ref->next;
1005 }
1006
1007 static struct ref *try_explicit_object_name(const char *name)
1008 {
1009         unsigned char sha1[20];
1010         struct ref *ref;
1011
1012         if (!*name) {
1013                 ref = alloc_ref("(delete)");
1014                 hashclr(ref->new_sha1);
1015                 return ref;
1016         }
1017         if (get_sha1(name, sha1))
1018                 return NULL;
1019         ref = alloc_ref(name);
1020         hashcpy(ref->new_sha1, sha1);
1021         return ref;
1022 }
1023
1024 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1025 {
1026         struct ref *ret = alloc_ref(name);
1027         tail_link_ref(ret, tail);
1028         return ret;
1029 }
1030
1031 static char *guess_ref(const char *name, struct ref *peer)
1032 {
1033         struct strbuf buf = STRBUF_INIT;
1034         unsigned char sha1[20];
1035
1036         const char *r = resolve_ref(peer->name, sha1, 1, NULL);
1037         if (!r)
1038                 return NULL;
1039
1040         if (!prefixcmp(r, "refs/heads/"))
1041                 strbuf_addstr(&buf, "refs/heads/");
1042         else if (!prefixcmp(r, "refs/tags/"))
1043                 strbuf_addstr(&buf, "refs/tags/");
1044         else
1045                 return NULL;
1046
1047         strbuf_addstr(&buf, name);
1048         return strbuf_detach(&buf, NULL);
1049 }
1050
1051 static int match_explicit(struct ref *src, struct ref *dst,
1052                           struct ref ***dst_tail,
1053                           struct refspec *rs)
1054 {
1055         struct ref *matched_src, *matched_dst;
1056         int copy_src;
1057
1058         const char *dst_value = rs->dst;
1059         char *dst_guess;
1060
1061         if (rs->pattern || rs->matching)
1062                 return 0;
1063
1064         matched_src = matched_dst = NULL;
1065         switch (count_refspec_match(rs->src, src, &matched_src)) {
1066         case 1:
1067                 copy_src = 1;
1068                 break;
1069         case 0:
1070                 /* The source could be in the get_sha1() format
1071                  * not a reference name.  :refs/other is a
1072                  * way to delete 'other' ref at the remote end.
1073                  */
1074                 matched_src = try_explicit_object_name(rs->src);
1075                 if (!matched_src)
1076                         return error("src refspec %s does not match any.", rs->src);
1077                 copy_src = 0;
1078                 break;
1079         default:
1080                 return error("src refspec %s matches more than one.", rs->src);
1081         }
1082
1083         if (!dst_value) {
1084                 unsigned char sha1[20];
1085                 int flag;
1086
1087                 dst_value = resolve_ref(matched_src->name, sha1, 1, &flag);
1088                 if (!dst_value ||
1089                     ((flag & REF_ISSYMREF) &&
1090                      prefixcmp(dst_value, "refs/heads/")))
1091                         die("%s cannot be resolved to branch.",
1092                             matched_src->name);
1093         }
1094
1095         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1096         case 1:
1097                 break;
1098         case 0:
1099                 if (!memcmp(dst_value, "refs/", 5))
1100                         matched_dst = make_linked_ref(dst_value, dst_tail);
1101                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1102                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1103                 else
1104                         error("unable to push to unqualified destination: %s\n"
1105                               "The destination refspec neither matches an "
1106                               "existing ref on the remote nor\n"
1107                               "begins with refs/, and we are unable to "
1108                               "guess a prefix based on the source ref.",
1109                               dst_value);
1110                 break;
1111         default:
1112                 matched_dst = NULL;
1113                 error("dst refspec %s matches more than one.",
1114                       dst_value);
1115                 break;
1116         }
1117         if (!matched_dst)
1118                 return -1;
1119         if (matched_dst->peer_ref)
1120                 return error("dst ref %s receives from more than one src.",
1121                       matched_dst->name);
1122         else {
1123                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1124                 matched_dst->force = rs->force;
1125         }
1126         return 0;
1127 }
1128
1129 static int match_explicit_refs(struct ref *src, struct ref *dst,
1130                                struct ref ***dst_tail, struct refspec *rs,
1131                                int rs_nr)
1132 {
1133         int i, errs;
1134         for (i = errs = 0; i < rs_nr; i++)
1135                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1136         return errs;
1137 }
1138
1139 static const struct refspec *check_pattern_match(const struct refspec *rs,
1140                                                  int rs_nr,
1141                                                  const struct ref *src)
1142 {
1143         int i;
1144         int matching_refs = -1;
1145         for (i = 0; i < rs_nr; i++) {
1146                 if (rs[i].matching &&
1147                     (matching_refs == -1 || rs[i].force)) {
1148                         matching_refs = i;
1149                         continue;
1150                 }
1151
1152                 if (rs[i].pattern && match_name_with_pattern(rs[i].src, src->name,
1153                                                              NULL, NULL))
1154                         return rs + i;
1155         }
1156         if (matching_refs != -1)
1157                 return rs + matching_refs;
1158         else
1159                 return NULL;
1160 }
1161
1162 static struct ref **tail_ref(struct ref **head)
1163 {
1164         struct ref **tail = head;
1165         while (*tail)
1166                 tail = &((*tail)->next);
1167         return tail;
1168 }
1169
1170 /*
1171  * Note. This is used only by "push"; refspec matching rules for
1172  * push and fetch are subtly different, so do not try to reuse it
1173  * without thinking.
1174  */
1175 int match_refs(struct ref *src, struct ref **dst,
1176                int nr_refspec, const char **refspec, int flags)
1177 {
1178         struct refspec *rs;
1179         int send_all = flags & MATCH_REFS_ALL;
1180         int send_mirror = flags & MATCH_REFS_MIRROR;
1181         int errs;
1182         static const char *default_refspec[] = { ":", NULL };
1183         struct ref **dst_tail = tail_ref(dst);
1184
1185         if (!nr_refspec) {
1186                 nr_refspec = 1;
1187                 refspec = default_refspec;
1188         }
1189         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1190         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1191
1192         /* pick the remainder */
1193         for ( ; src; src = src->next) {
1194                 struct ref *dst_peer;
1195                 const struct refspec *pat = NULL;
1196                 char *dst_name;
1197                 if (src->peer_ref)
1198                         continue;
1199
1200                 pat = check_pattern_match(rs, nr_refspec, src);
1201                 if (!pat)
1202                         continue;
1203
1204                 if (pat->matching) {
1205                         /*
1206                          * "matching refs"; traditionally we pushed everything
1207                          * including refs outside refs/heads/ hierarchy, but
1208                          * that does not make much sense these days.
1209                          */
1210                         if (!send_mirror && prefixcmp(src->name, "refs/heads/"))
1211                                 continue;
1212                         dst_name = xstrdup(src->name);
1213
1214                 } else {
1215                         const char *dst_side = pat->dst ? pat->dst : pat->src;
1216                         if (!match_name_with_pattern(pat->src, src->name,
1217                                                      dst_side, &dst_name))
1218                                 die("Didn't think it matches any more");
1219                 }
1220                 dst_peer = find_ref_by_name(*dst, dst_name);
1221                 if (dst_peer) {
1222                         if (dst_peer->peer_ref)
1223                                 /* We're already sending something to this ref. */
1224                                 goto free_name;
1225
1226                 } else {
1227                         if (pat->matching && !(send_all || send_mirror))
1228                                 /*
1229                                  * Remote doesn't have it, and we have no
1230                                  * explicit pattern, and we don't have
1231                                  * --all nor --mirror.
1232                                  */
1233                                 goto free_name;
1234
1235                         /* Create a new one and link it */
1236                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1237                         hashcpy(dst_peer->new_sha1, src->new_sha1);
1238                 }
1239                 dst_peer->peer_ref = copy_ref(src);
1240                 dst_peer->force = pat->force;
1241         free_name:
1242                 free(dst_name);
1243         }
1244         if (errs)
1245                 return -1;
1246         return 0;
1247 }
1248
1249 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1250         int force_update)
1251 {
1252         struct ref *ref;
1253
1254         for (ref = remote_refs; ref; ref = ref->next) {
1255                 if (ref->peer_ref)
1256                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1257                 else if (!send_mirror)
1258                         continue;
1259
1260                 ref->deletion = is_null_sha1(ref->new_sha1);
1261                 if (!ref->deletion &&
1262                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1263                         ref->status = REF_STATUS_UPTODATE;
1264                         continue;
1265                 }
1266
1267                 /* This part determines what can overwrite what.
1268                  * The rules are:
1269                  *
1270                  * (0) you can always use --force or +A:B notation to
1271                  *     selectively force individual ref pairs.
1272                  *
1273                  * (1) if the old thing does not exist, it is OK.
1274                  *
1275                  * (2) if you do not have the old thing, you are not allowed
1276                  *     to overwrite it; you would not know what you are losing
1277                  *     otherwise.
1278                  *
1279                  * (3) if both new and old are commit-ish, and new is a
1280                  *     descendant of old, it is OK.
1281                  *
1282                  * (4) regardless of all of the above, removing :B is
1283                  *     always allowed.
1284                  */
1285
1286                 ref->nonfastforward =
1287                         !ref->deletion &&
1288                         !is_null_sha1(ref->old_sha1) &&
1289                         (!has_sha1_file(ref->old_sha1)
1290                           || !ref_newer(ref->new_sha1, ref->old_sha1));
1291
1292                 if (ref->nonfastforward && !ref->force && !force_update) {
1293                         ref->status = REF_STATUS_REJECT_NONFASTFORWARD;
1294                         continue;
1295                 }
1296         }
1297 }
1298
1299 struct branch *branch_get(const char *name)
1300 {
1301         struct branch *ret;
1302
1303         read_config();
1304         if (!name || !*name || !strcmp(name, "HEAD"))
1305                 ret = current_branch;
1306         else
1307                 ret = make_branch(name, 0);
1308         if (ret && ret->remote_name) {
1309                 ret->remote = remote_get(ret->remote_name);
1310                 if (ret->merge_nr) {
1311                         int i;
1312                         ret->merge = xcalloc(sizeof(*ret->merge),
1313                                              ret->merge_nr);
1314                         for (i = 0; i < ret->merge_nr; i++) {
1315                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1316                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1317                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1318                                     && !strcmp(ret->remote_name, "."))
1319                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1320                         }
1321                 }
1322         }
1323         return ret;
1324 }
1325
1326 int branch_has_merge_config(struct branch *branch)
1327 {
1328         return branch && !!branch->merge;
1329 }
1330
1331 int branch_merge_matches(struct branch *branch,
1332                                  int i,
1333                                  const char *refname)
1334 {
1335         if (!branch || i < 0 || i >= branch->merge_nr)
1336                 return 0;
1337         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1338 }
1339
1340 static struct ref *get_expanded_map(const struct ref *remote_refs,
1341                                     const struct refspec *refspec)
1342 {
1343         const struct ref *ref;
1344         struct ref *ret = NULL;
1345         struct ref **tail = &ret;
1346
1347         char *expn_name;
1348
1349         for (ref = remote_refs; ref; ref = ref->next) {
1350                 if (strchr(ref->name, '^'))
1351                         continue; /* a dereference item */
1352                 if (match_name_with_pattern(refspec->src, ref->name,
1353                                             refspec->dst, &expn_name)) {
1354                         struct ref *cpy = copy_ref(ref);
1355
1356                         cpy->peer_ref = alloc_ref(expn_name);
1357                         free(expn_name);
1358                         if (refspec->force)
1359                                 cpy->peer_ref->force = 1;
1360                         *tail = cpy;
1361                         tail = &cpy->next;
1362                 }
1363         }
1364
1365         return ret;
1366 }
1367
1368 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1369 {
1370         const struct ref *ref;
1371         for (ref = refs; ref; ref = ref->next) {
1372                 if (refname_match(name, ref->name, ref_fetch_rules))
1373                         return ref;
1374         }
1375         return NULL;
1376 }
1377
1378 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1379 {
1380         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1381
1382         if (!ref)
1383                 return NULL;
1384
1385         return copy_ref(ref);
1386 }
1387
1388 static struct ref *get_local_ref(const char *name)
1389 {
1390         if (!name || name[0] == '\0')
1391                 return NULL;
1392
1393         if (!prefixcmp(name, "refs/"))
1394                 return alloc_ref(name);
1395
1396         if (!prefixcmp(name, "heads/") ||
1397             !prefixcmp(name, "tags/") ||
1398             !prefixcmp(name, "remotes/"))
1399                 return alloc_ref_with_prefix("refs/", 5, name);
1400
1401         return alloc_ref_with_prefix("refs/heads/", 11, name);
1402 }
1403
1404 int get_fetch_map(const struct ref *remote_refs,
1405                   const struct refspec *refspec,
1406                   struct ref ***tail,
1407                   int missing_ok)
1408 {
1409         struct ref *ref_map, **rmp;
1410
1411         if (refspec->pattern) {
1412                 ref_map = get_expanded_map(remote_refs, refspec);
1413         } else {
1414                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1415
1416                 ref_map = get_remote_ref(remote_refs, name);
1417                 if (!missing_ok && !ref_map)
1418                         die("Couldn't find remote ref %s", name);
1419                 if (ref_map) {
1420                         ref_map->peer_ref = get_local_ref(refspec->dst);
1421                         if (ref_map->peer_ref && refspec->force)
1422                                 ref_map->peer_ref->force = 1;
1423                 }
1424         }
1425
1426         for (rmp = &ref_map; *rmp; ) {
1427                 if ((*rmp)->peer_ref) {
1428                         int st = check_ref_format((*rmp)->peer_ref->name + 5);
1429                         if (st && st != CHECK_REF_FORMAT_ONELEVEL) {
1430                                 struct ref *ignore = *rmp;
1431                                 error("* Ignoring funny ref '%s' locally",
1432                                       (*rmp)->peer_ref->name);
1433                                 *rmp = (*rmp)->next;
1434                                 free(ignore->peer_ref);
1435                                 free(ignore);
1436                                 continue;
1437                         }
1438                 }
1439                 rmp = &((*rmp)->next);
1440         }
1441
1442         if (ref_map)
1443                 tail_link_ref(ref_map, tail);
1444
1445         return 0;
1446 }
1447
1448 int resolve_remote_symref(struct ref *ref, struct ref *list)
1449 {
1450         if (!ref->symref)
1451                 return 0;
1452         for (; list; list = list->next)
1453                 if (!strcmp(ref->symref, list->name)) {
1454                         hashcpy(ref->old_sha1, list->old_sha1);
1455                         return 0;
1456                 }
1457         return 1;
1458 }
1459
1460 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1461 {
1462         while (list) {
1463                 struct commit_list *temp = list;
1464                 temp->item->object.flags &= ~mark;
1465                 list = temp->next;
1466                 free(temp);
1467         }
1468 }
1469
1470 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1471 {
1472         struct object *o;
1473         struct commit *old, *new;
1474         struct commit_list *list, *used;
1475         int found = 0;
1476
1477         /* Both new and old must be commit-ish and new is descendant of
1478          * old.  Otherwise we require --force.
1479          */
1480         o = deref_tag(parse_object(old_sha1), NULL, 0);
1481         if (!o || o->type != OBJ_COMMIT)
1482                 return 0;
1483         old = (struct commit *) o;
1484
1485         o = deref_tag(parse_object(new_sha1), NULL, 0);
1486         if (!o || o->type != OBJ_COMMIT)
1487                 return 0;
1488         new = (struct commit *) o;
1489
1490         if (parse_commit(new) < 0)
1491                 return 0;
1492
1493         used = list = NULL;
1494         commit_list_insert(new, &list);
1495         while (list) {
1496                 new = pop_most_recent_commit(&list, TMP_MARK);
1497                 commit_list_insert(new, &used);
1498                 if (new == old) {
1499                         found = 1;
1500                         break;
1501                 }
1502         }
1503         unmark_and_free(list, TMP_MARK);
1504         unmark_and_free(used, TMP_MARK);
1505         return found;
1506 }
1507
1508 /*
1509  * Return true if there is anything to report, otherwise false.
1510  */
1511 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1512 {
1513         unsigned char sha1[20];
1514         struct commit *ours, *theirs;
1515         char symmetric[84];
1516         struct rev_info revs;
1517         const char *rev_argv[10], *base;
1518         int rev_argc;
1519
1520         /*
1521          * Nothing to report unless we are marked to build on top of
1522          * somebody else.
1523          */
1524         if (!branch ||
1525             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1526                 return 0;
1527
1528         /*
1529          * If what we used to build on no longer exists, there is
1530          * nothing to report.
1531          */
1532         base = branch->merge[0]->dst;
1533         if (!resolve_ref(base, sha1, 1, NULL))
1534                 return 0;
1535         theirs = lookup_commit_reference(sha1);
1536         if (!theirs)
1537                 return 0;
1538
1539         if (!resolve_ref(branch->refname, sha1, 1, NULL))
1540                 return 0;
1541         ours = lookup_commit_reference(sha1);
1542         if (!ours)
1543                 return 0;
1544
1545         /* are we the same? */
1546         if (theirs == ours)
1547                 return 0;
1548
1549         /* Run "rev-list --left-right ours...theirs" internally... */
1550         rev_argc = 0;
1551         rev_argv[rev_argc++] = NULL;
1552         rev_argv[rev_argc++] = "--left-right";
1553         rev_argv[rev_argc++] = symmetric;
1554         rev_argv[rev_argc++] = "--";
1555         rev_argv[rev_argc] = NULL;
1556
1557         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1558         strcpy(symmetric + 40, "...");
1559         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1560
1561         init_revisions(&revs, NULL);
1562         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1563         prepare_revision_walk(&revs);
1564
1565         /* ... and count the commits on each side. */
1566         *num_ours = 0;
1567         *num_theirs = 0;
1568         while (1) {
1569                 struct commit *c = get_revision(&revs);
1570                 if (!c)
1571                         break;
1572                 if (c->object.flags & SYMMETRIC_LEFT)
1573                         (*num_ours)++;
1574                 else
1575                         (*num_theirs)++;
1576         }
1577
1578         /* clear object flags smudged by the above traversal */
1579         clear_commit_marks(ours, ALL_REV_FLAGS);
1580         clear_commit_marks(theirs, ALL_REV_FLAGS);
1581         return 1;
1582 }
1583
1584 /*
1585  * Return true when there is anything to report, otherwise false.
1586  */
1587 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1588 {
1589         int num_ours, num_theirs;
1590         const char *base;
1591
1592         if (!stat_tracking_info(branch, &num_ours, &num_theirs))
1593                 return 0;
1594
1595         base = branch->merge[0]->dst;
1596         base = shorten_unambiguous_ref(base, 0);
1597         if (!num_theirs)
1598                 strbuf_addf(sb, "Your branch is ahead of '%s' "
1599                             "by %d commit%s.\n",
1600                             base, num_ours, (num_ours == 1) ? "" : "s");
1601         else if (!num_ours)
1602                 strbuf_addf(sb, "Your branch is behind '%s' "
1603                             "by %d commit%s, "
1604                             "and can be fast-forwarded.\n",
1605                             base, num_theirs, (num_theirs == 1) ? "" : "s");
1606         else
1607                 strbuf_addf(sb, "Your branch and '%s' have diverged,\n"
1608                             "and have %d and %d different commit(s) each, "
1609                             "respectively.\n",
1610                             base, num_ours, num_theirs);
1611         return 1;
1612 }
1613
1614 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1615 {
1616         struct ref ***local_tail = cb_data;
1617         struct ref *ref;
1618         int len;
1619
1620         /* we already know it starts with refs/ to get here */
1621         if (check_ref_format(refname + 5))
1622                 return 0;
1623
1624         len = strlen(refname) + 1;
1625         ref = xcalloc(1, sizeof(*ref) + len);
1626         hashcpy(ref->new_sha1, sha1);
1627         memcpy(ref->name, refname, len);
1628         **local_tail = ref;
1629         *local_tail = &ref->next;
1630         return 0;
1631 }
1632
1633 struct ref *get_local_heads(void)
1634 {
1635         struct ref *local_refs = NULL, **local_tail = &local_refs;
1636         for_each_ref(one_local_ref, &local_tail);
1637         return local_refs;
1638 }
1639
1640 struct ref *guess_remote_head(const struct ref *head,
1641                               const struct ref *refs,
1642                               int all)
1643 {
1644         const struct ref *r;
1645         struct ref *list = NULL;
1646         struct ref **tail = &list;
1647
1648         if (!head)
1649                 return NULL;
1650
1651         /*
1652          * Some transports support directly peeking at
1653          * where HEAD points; if that is the case, then
1654          * we don't have to guess.
1655          */
1656         if (head->symref)
1657                 return copy_ref(find_ref_by_name(refs, head->symref));
1658
1659         /* If refs/heads/master could be right, it is. */
1660         if (!all) {
1661                 r = find_ref_by_name(refs, "refs/heads/master");
1662                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1663                         return copy_ref(r);
1664         }
1665
1666         /* Look for another ref that points there */
1667         for (r = refs; r; r = r->next) {
1668                 if (r != head && !hashcmp(r->old_sha1, head->old_sha1)) {
1669                         *tail = copy_ref(r);
1670                         tail = &((*tail)->next);
1671                         if (!all)
1672                                 break;
1673                 }
1674         }
1675
1676         return list;
1677 }
1678
1679 struct stale_heads_info {
1680         struct remote *remote;
1681         struct string_list *ref_names;
1682         struct ref **stale_refs_tail;
1683 };
1684
1685 static int get_stale_heads_cb(const char *refname,
1686         const unsigned char *sha1, int flags, void *cb_data)
1687 {
1688         struct stale_heads_info *info = cb_data;
1689         struct refspec refspec;
1690         memset(&refspec, 0, sizeof(refspec));
1691         refspec.dst = (char *)refname;
1692         if (!remote_find_tracking(info->remote, &refspec)) {
1693                 if (!((flags & REF_ISSYMREF) ||
1694                     string_list_has_string(info->ref_names, refspec.src))) {
1695                         struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
1696                         hashcpy(ref->new_sha1, sha1);
1697                 }
1698         }
1699         return 0;
1700 }
1701
1702 struct ref *get_stale_heads(struct remote *remote, struct ref *fetch_map)
1703 {
1704         struct ref *ref, *stale_refs = NULL;
1705         struct string_list ref_names = { NULL, 0, 0, 0 };
1706         struct stale_heads_info info;
1707         info.remote = remote;
1708         info.ref_names = &ref_names;
1709         info.stale_refs_tail = &stale_refs;
1710         for (ref = fetch_map; ref; ref = ref->next)
1711                 string_list_append(ref->name, &ref_names);
1712         sort_string_list(&ref_names);
1713         for_each_ref(get_stale_heads_cb, &info);
1714         string_list_clear(&ref_names, 0);
1715         return stale_refs;
1716 }