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 #include "mergesort.h"
  11
  12 enum map_direction { FROM_SRC, FROM_DST };
  13
  14 static struct refspec s_tag_refspec = {
  15         0,
  16         1,
  17         0,
  18         "refs/tags/*",
  19         "refs/tags/*"
  20 };
  21
  22 const struct refspec *tag_refspec = &s_tag_refspec;
  23
  24 struct counted_string {
  25         size_t len;
  26         const char *s;
  27 };
  28 struct rewrite {
  29         const char *base;
  30         size_t baselen;
  31         struct counted_string *instead_of;
  32         int instead_of_nr;
  33         int instead_of_alloc;
  34 };
  35 struct rewrites {
  36         struct rewrite **rewrite;
  37         int rewrite_alloc;
  38         int rewrite_nr;
  39 };
  40
  41 static struct remote **remotes;
  42 static int remotes_alloc;
  43 static int remotes_nr;
  44
  45 static struct branch **branches;
  46 static int branches_alloc;
  47 static int branches_nr;
  48
  49 static struct branch *current_branch;
  50 static const char *default_remote_name;
  51 static int explicit_default_remote_name;
  52
  53 static struct rewrites rewrites;
  54 static struct rewrites rewrites_push;
  55
  56 #define BUF_SIZE (2048)
  57 static char buffer[BUF_SIZE];
  58
  59 static int valid_remote(const struct remote *remote)
  60 {
  61         return (!!remote->url) || (!!remote->foreign_vcs);
  62 }
  63
  64 static const char *alias_url(const char *url, struct rewrites *r)
  65 {
  66         int i, j;
  67         char *ret;
  68         struct counted_string *longest;
  69         int longest_i;
  70
  71         longest = NULL;
  72         longest_i = -1;
  73         for (i = 0; i < r->rewrite_nr; i++) {
  74                 if (!r->rewrite[i])
  75                         continue;
  76                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  77                         if (!prefixcmp(url, r->rewrite[i]->instead_of[j].s) &&
  78                             (!longest ||
  79                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  80                                 longest = &(r->rewrite[i]->instead_of[j]);
  81                                 longest_i = i;
  82                         }
  83                 }
  84         }
  85         if (!longest)
  86                 return url;
  87
  88         ret = xmalloc(r->rewrite[longest_i]->baselen +
  89                      (strlen(url) - longest->len) + 1);
  90         strcpy(ret, r->rewrite[longest_i]->base);
  91         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
  92         return ret;
  93 }
  94
  95 static void add_push_refspec(struct remote *remote, const char *ref)
  96 {
  97         ALLOC_GROW(remote->push_refspec,
  98                    remote->push_refspec_nr + 1,
  99                    remote->push_refspec_alloc);
 100         remote->push_refspec[remote->push_refspec_nr++] = ref;
 101 }
 102
 103 static void add_fetch_refspec(struct remote *remote, const char *ref)
 104 {
 105         ALLOC_GROW(remote->fetch_refspec,
 106                    remote->fetch_refspec_nr + 1,
 107                    remote->fetch_refspec_alloc);
 108         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
 109 }
 110
 111 static void add_url(struct remote *remote, const char *url)
 112 {
 113         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
 114         remote->url[remote->url_nr++] = url;
 115 }
 116
 117 static void add_pushurl(struct remote *remote, const char *pushurl)
 118 {
 119         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
 120         remote->pushurl[remote->pushurl_nr++] = pushurl;
 121 }
 122
 123 static void add_pushurl_alias(struct remote *remote, const char *url)
 124 {
 125         const char *pushurl = alias_url(url, &rewrites_push);
 126         if (pushurl != url)
 127                 add_pushurl(remote, pushurl);
 128 }
 129
 130 static void add_url_alias(struct remote *remote, const char *url)
 131 {
 132         add_url(remote, alias_url(url, &rewrites));
 133         add_pushurl_alias(remote, url);
 134 }
 135
 136 static struct remote *make_remote(const char *name, int len)
 137 {
 138         struct remote *ret;
 139         int i;
 140
 141         for (i = 0; i < remotes_nr; i++) {
 142                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
 143                            !remotes[i]->name[len]) :
 144                     !strcmp(name, remotes[i]->name))
 145                         return remotes[i];
 146         }
 147
 148         ret = xcalloc(1, sizeof(struct remote));
 149         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 150         remotes[remotes_nr++] = ret;
 151         if (len)
 152                 ret->name = xstrndup(name, len);
 153         else
 154                 ret->name = xstrdup(name);
 155         return ret;
 156 }
 157
 158 static void add_merge(struct branch *branch, const char *name)
 159 {
 160         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 161                    branch->merge_alloc);
 162         branch->merge_name[branch->merge_nr++] = name;
 163 }
 164
 165 static struct branch *make_branch(const char *name, int len)
 166 {
 167         struct branch *ret;
 168         int i;
 169         char *refname;
 170
 171         for (i = 0; i < branches_nr; i++) {
 172                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 173                            !branches[i]->name[len]) :
 174                     !strcmp(name, branches[i]->name))
 175                         return branches[i];
 176         }
 177
 178         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 179         ret = xcalloc(1, sizeof(struct branch));
 180         branches[branches_nr++] = ret;
 181         if (len)
 182                 ret->name = xstrndup(name, len);
 183         else
 184                 ret->name = xstrdup(name);
 185         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
 186         strcpy(refname, "refs/heads/");
 187         strcpy(refname + strlen("refs/heads/"), ret->name);
 188         ret->refname = refname;
 189
 190         return ret;
 191 }
 192
 193 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 194 {
 195         struct rewrite *ret;
 196         int i;
 197
 198         for (i = 0; i < r->rewrite_nr; i++) {
 199                 if (len
 200                     ? (len == r->rewrite[i]->baselen &&
 201                        !strncmp(base, r->rewrite[i]->base, len))
 202                     : !strcmp(base, r->rewrite[i]->base))
 203                         return r->rewrite[i];
 204         }
 205
 206         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 207         ret = xcalloc(1, sizeof(struct rewrite));
 208         r->rewrite[r->rewrite_nr++] = ret;
 209         if (len) {
 210                 ret->base = xstrndup(base, len);
 211                 ret->baselen = len;
 212         }
 213         else {
 214                 ret->base = xstrdup(base);
 215                 ret->baselen = strlen(base);
 216         }
 217         return ret;
 218 }
 219
 220 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 221 {
 222         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 223         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 224         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 225         rewrite->instead_of_nr++;
 226 }
 227
 228 static void read_remotes_file(struct remote *remote)
 229 {
 230         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 231
 232         if (!f)
 233                 return;
 234         remote->origin = REMOTE_REMOTES;
 235         while (fgets(buffer, BUF_SIZE, f)) {
 236                 int value_list;
 237                 char *s, *p;
 238
 239                 if (!prefixcmp(buffer, "URL:")) {
 240                         value_list = 0;
 241                         s = buffer + 4;
 242                 } else if (!prefixcmp(buffer, "Push:")) {
 243                         value_list = 1;
 244                         s = buffer + 5;
 245                 } else if (!prefixcmp(buffer, "Pull:")) {
 246                         value_list = 2;
 247                         s = buffer + 5;
 248                 } else
 249                         continue;
 250
 251                 while (isspace(*s))
 252                         s++;
 253                 if (!*s)
 254                         continue;
 255
 256                 p = s + strlen(s);
 257                 while (isspace(p[-1]))
 258                         *--p = 0;
 259
 260                 switch (value_list) {
 261                 case 0:
 262                         add_url_alias(remote, xstrdup(s));
 263                         break;
 264                 case 1:
 265                         add_push_refspec(remote, xstrdup(s));
 266                         break;
 267                 case 2:
 268                         add_fetch_refspec(remote, xstrdup(s));
 269                         break;
 270                 }
 271         }
 272         fclose(f);
 273 }
 274
 275 static void read_branches_file(struct remote *remote)
 276 {
 277         const char *slash = strchr(remote->name, '/');
 278         char *frag;
 279         struct strbuf branch = STRBUF_INIT;
 280         int n = slash ? slash - remote->name : 1000;
 281         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
 282         char *s, *p;
 283         int len;
 284
 285         if (!f)
 286                 return;
 287         s = fgets(buffer, BUF_SIZE, f);
 288         fclose(f);
 289         if (!s)
 290                 return;
 291         while (isspace(*s))
 292                 s++;
 293         if (!*s)
 294                 return;
 295         remote->origin = REMOTE_BRANCHES;
 296         p = s + strlen(s);
 297         while (isspace(p[-1]))
 298                 *--p = 0;
 299         len = p - s;
 300         if (slash)
 301                 len += strlen(slash);
 302         p = xmalloc(len + 1);
 303         strcpy(p, s);
 304         if (slash)
 305                 strcat(p, slash);
 306
 307         /*
 308          * With "slash", e.g. "git fetch jgarzik/netdev-2.6" when
 309          * reading from $GIT_DIR/branches/jgarzik fetches "HEAD" from
 310          * the partial URL obtained from the branches file plus
 311          * "/netdev-2.6" and does not store it in any tracking ref.
 312          * #branch specifier in the file is ignored.
 313          *
 314          * Otherwise, the branches file would have URL and optionally
 315          * #branch specified.  The "master" (or specified) branch is
 316          * fetched and stored in the local branch of the same name.
 317          */
 318         frag = strchr(p, '#');
 319         if (frag) {
 320                 *(frag++) = '\0';
 321                 strbuf_addf(&branch, "refs/heads/%s", frag);
 322         } else
 323                 strbuf_addstr(&branch, "refs/heads/master");
 324         if (!slash) {
 325                 strbuf_addf(&branch, ":refs/heads/%s", remote->name);
 326         } else {
 327                 strbuf_reset(&branch);
 328                 strbuf_addstr(&branch, "HEAD:");
 329         }
 330         add_url_alias(remote, p);
 331         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
 332         /*
 333          * Cogito compatible push: push current HEAD to remote #branch
 334          * (master if missing)
 335          */
 336         strbuf_init(&branch, 0);
 337         strbuf_addstr(&branch, "HEAD");
 338         if (frag)
 339                 strbuf_addf(&branch, ":refs/heads/%s", frag);
 340         else
 341                 strbuf_addstr(&branch, ":refs/heads/master");
 342         add_push_refspec(remote, strbuf_detach(&branch, NULL));
 343         remote->fetch_tags = 1; /* always auto-follow */
 344 }
 345
 346 static int handle_config(const char *key, const char *value, void *cb)
 347 {
 348         const char *name;
 349         const char *subkey;
 350         struct remote *remote;
 351         struct branch *branch;
 352         if (!prefixcmp(key, "branch.")) {
 353                 name = key + 7;
 354                 subkey = strrchr(name, '.');
 355                 if (!subkey)
 356                         return 0;
 357                 branch = make_branch(name, subkey - name);
 358                 if (!strcmp(subkey, ".remote")) {
 359                         if (!value)
 360                                 return config_error_nonbool(key);
 361                         branch->remote_name = xstrdup(value);
 362                         if (branch == current_branch) {
 363                                 default_remote_name = branch->remote_name;
 364                                 explicit_default_remote_name = 1;
 365                         }
 366                 } else if (!strcmp(subkey, ".merge")) {
 367                         if (!value)
 368                                 return config_error_nonbool(key);
 369                         add_merge(branch, xstrdup(value));
 370                 }
 371                 return 0;
 372         }
 373         if (!prefixcmp(key, "url.")) {
 374                 struct rewrite *rewrite;
 375                 name = key + 4;
 376                 subkey = strrchr(name, '.');
 377                 if (!subkey)
 378                         return 0;
 379                 if (!strcmp(subkey, ".insteadof")) {
 380                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 381                         if (!value)
 382                                 return config_error_nonbool(key);
 383                         add_instead_of(rewrite, xstrdup(value));
 384                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 385                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 386                         if (!value)
 387                                 return config_error_nonbool(key);
 388                         add_instead_of(rewrite, xstrdup(value));
 389                 }
 390         }
 391         if (prefixcmp(key,  "remote."))
 392                 return 0;
 393         name = key + 7;
 394         if (*name == '/') {
 395                 warning("Config remote shorthand cannot begin with '/': %s",
 396                         name);
 397                 return 0;
 398         }
 399         subkey = strrchr(name, '.');
 400         if (!subkey)
 401                 return 0;
 402         remote = make_remote(name, subkey - name);
 403         remote->origin = REMOTE_CONFIG;
 404         if (!strcmp(subkey, ".mirror"))
 405                 remote->mirror = git_config_bool(key, value);
 406         else if (!strcmp(subkey, ".skipdefaultupdate"))
 407                 remote->skip_default_update = git_config_bool(key, value);
 408         else if (!strcmp(subkey, ".skipfetchall"))
 409                 remote->skip_default_update = git_config_bool(key, value);
 410         else if (!strcmp(subkey, ".url")) {
 411                 const char *v;
 412                 if (git_config_string(&v, key, value))
 413                         return -1;
 414                 add_url(remote, v);
 415         } else if (!strcmp(subkey, ".pushurl")) {
 416                 const char *v;
 417                 if (git_config_string(&v, key, value))
 418                         return -1;
 419                 add_pushurl(remote, v);
 420         } else if (!strcmp(subkey, ".push")) {
 421                 const char *v;
 422                 if (git_config_string(&v, key, value))
 423                         return -1;
 424                 add_push_refspec(remote, v);
 425         } else if (!strcmp(subkey, ".fetch")) {
 426                 const char *v;
 427                 if (git_config_string(&v, key, value))
 428                         return -1;
 429                 add_fetch_refspec(remote, v);
 430         } else if (!strcmp(subkey, ".receivepack")) {
 431                 const char *v;
 432                 if (git_config_string(&v, key, value))
 433                         return -1;
 434                 if (!remote->receivepack)
 435                         remote->receivepack = v;
 436                 else
 437                         error("more than one receivepack given, using the first");
 438         } else if (!strcmp(subkey, ".uploadpack")) {
 439                 const char *v;
 440                 if (git_config_string(&v, key, value))
 441                         return -1;
 442                 if (!remote->uploadpack)
 443                         remote->uploadpack = v;
 444                 else
 445                         error("more than one uploadpack given, using the first");
 446         } else if (!strcmp(subkey, ".tagopt")) {
 447                 if (!strcmp(value, "--no-tags"))
 448                         remote->fetch_tags = -1;
 449                 else if (!strcmp(value, "--tags"))
 450                         remote->fetch_tags = 2;
 451         } else if (!strcmp(subkey, ".proxy")) {
 452                 return git_config_string((const char **)&remote->http_proxy,
 453                                          key, value);
 454         } else if (!strcmp(subkey, ".vcs")) {
 455                 return git_config_string(&remote->foreign_vcs, key, value);
 456         }
 457         return 0;
 458 }
 459
 460 static void alias_all_urls(void)
 461 {
 462         int i, j;
 463         for (i = 0; i < remotes_nr; i++) {
 464                 int add_pushurl_aliases;
 465                 if (!remotes[i])
 466                         continue;
 467                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 468                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 469                 }
 470                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 471                 for (j = 0; j < remotes[i]->url_nr; j++) {
 472                         if (add_pushurl_aliases)
 473                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 474                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 475                 }
 476         }
 477 }
 478
 479 static void read_config(void)
 480 {
 481         unsigned char sha1[20];
 482         const char *head_ref;
 483         int flag;
 484         if (default_remote_name) /* did this already */
 485                 return;
 486         default_remote_name = xstrdup("origin");
 487         current_branch = NULL;
 488         head_ref = resolve_ref_unsafe("HEAD", sha1, 0, &flag);
 489         if (head_ref && (flag & REF_ISSYMREF) &&
 490             !prefixcmp(head_ref, "refs/heads/")) {
 491                 current_branch =
 492                         make_branch(head_ref + strlen("refs/heads/"), 0);
 493         }
 494         git_config(handle_config, NULL);
 495         alias_all_urls();
 496 }
 497
 498 /*
 499  * This function frees a refspec array.
 500  * Warning: code paths should be checked to ensure that the src
 501  *          and dst pointers are always freeable pointers as well
 502  *          as the refspec pointer itself.
 503  */
 504 static void free_refspecs(struct refspec *refspec, int nr_refspec)
 505 {
 506         int i;
 507
 508         if (!refspec)
 509                 return;
 510
 511         for (i = 0; i < nr_refspec; i++) {
 512                 free(refspec[i].src);
 513                 free(refspec[i].dst);
 514         }
 515         free(refspec);
 516 }
 517
 518 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 519 {
 520         int i;
 521         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 522
 523         for (i = 0; i < nr_refspec; i++) {
 524                 size_t llen;
 525                 int is_glob;
 526                 const char *lhs, *rhs;
 527                 int flags;
 528
 529                 is_glob = 0;
 530
 531                 lhs = refspec[i];
 532                 if (*lhs == '+') {
 533                         rs[i].force = 1;
 534                         lhs++;
 535                 }
 536
 537                 rhs = strrchr(lhs, ':');
 538
 539                 /*
 540                  * Before going on, special case ":" (or "+:") as a refspec
 541                  * for matching refs.
 542                  */
 543                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
 544                         rs[i].matching = 1;
 545                         continue;
 546                 }
 547
 548                 if (rhs) {
 549                         size_t rlen = strlen(++rhs);
 550                         is_glob = (1 <= rlen && strchr(rhs, '*'));
 551                         rs[i].dst = xstrndup(rhs, rlen);
 552                 }
 553
 554                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 555                 if (1 <= llen && memchr(lhs, '*', llen)) {
 556                         if ((rhs && !is_glob) || (!rhs && fetch))
 557                                 goto invalid;
 558                         is_glob = 1;
 559                 } else if (rhs && is_glob) {
 560                         goto invalid;
 561                 }
 562
 563                 rs[i].pattern = is_glob;
 564                 rs[i].src = xstrndup(lhs, llen);
 565                 flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
 566
 567                 if (fetch) {
 568                         /*
 569                          * LHS
 570                          * - empty is allowed; it means HEAD.
 571                          * - otherwise it must be a valid looking ref.
 572                          */
 573                         if (!*rs[i].src)
 574                                 ; /* empty is ok */
 575                         else if (check_refname_format(rs[i].src, flags))
 576                                 goto invalid;
 577                         /*
 578                          * RHS
 579                          * - missing is ok, and is same as empty.
 580                          * - empty is ok; it means not to store.
 581                          * - otherwise it must be a valid looking ref.
 582                          */
 583                         if (!rs[i].dst)
 584                                 ; /* ok */
 585                         else if (!*rs[i].dst)
 586                                 ; /* ok */
 587                         else if (check_refname_format(rs[i].dst, flags))
 588                                 goto invalid;
 589                 } else {
 590                         /*
 591                          * LHS
 592                          * - empty is allowed; it means delete.
 593                          * - when wildcarded, it must be a valid looking ref.
 594                          * - otherwise, it must be an extended SHA-1, but
 595                          *   there is no existing way to validate this.
 596                          */
 597                         if (!*rs[i].src)
 598                                 ; /* empty is ok */
 599                         else if (is_glob) {
 600                                 if (check_refname_format(rs[i].src, flags))
 601                                         goto invalid;
 602                         }
 603                         else
 604                                 ; /* anything goes, for now */
 605                         /*
 606                          * RHS
 607                          * - missing is allowed, but LHS then must be a
 608                          *   valid looking ref.
 609                          * - empty is not allowed.
 610                          * - otherwise it must be a valid looking ref.
 611                          */
 612                         if (!rs[i].dst) {
 613                                 if (check_refname_format(rs[i].src, flags))
 614                                         goto invalid;
 615                         } else if (!*rs[i].dst) {
 616                                 goto invalid;
 617                         } else {
 618                                 if (check_refname_format(rs[i].dst, flags))
 619                                         goto invalid;
 620                         }
 621                 }
 622         }
 623         return rs;
 624
 625  invalid:
 626         if (verify) {
 627                 /*
 628                  * nr_refspec must be greater than zero and i must be valid
 629                  * since it is only possible to reach this point from within
 630                  * the for loop above.
 631                  */
 632                 free_refspecs(rs, i+1);
 633                 return NULL;
 634         }
 635         die("Invalid refspec '%s'", refspec[i]);
 636 }
 637
 638 int valid_fetch_refspec(const char *fetch_refspec_str)
 639 {
 640         struct refspec *refspec;
 641
 642         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
 643         free_refspecs(refspec, 1);
 644         return !!refspec;
 645 }
 646
 647 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 648 {
 649         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 650 }
 651
 652 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 653 {
 654         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 655 }
 656
 657 void free_refspec(int nr_refspec, struct refspec *refspec)
 658 {
 659         int i;
 660         for (i = 0; i < nr_refspec; i++) {
 661                 free(refspec[i].src);
 662                 free(refspec[i].dst);
 663         }
 664         free(refspec);
 665 }
 666
 667 static int valid_remote_nick(const char *name)
 668 {
 669         if (!name[0] || is_dot_or_dotdot(name))
 670                 return 0;
 671         return !strchr(name, '/'); /* no slash */
 672 }
 673
 674 struct remote *remote_get(const char *name)
 675 {
 676         struct remote *ret;
 677         int name_given = 0;
 678
 679         read_config();
 680         if (name)
 681                 name_given = 1;
 682         else {
 683                 name = default_remote_name;
 684                 name_given = explicit_default_remote_name;
 685         }
 686
 687         ret = make_remote(name, 0);
 688         if (valid_remote_nick(name)) {
 689                 if (!valid_remote(ret))
 690                         read_remotes_file(ret);
 691                 if (!valid_remote(ret))
 692                         read_branches_file(ret);
 693         }
 694         if (name_given && !valid_remote(ret))
 695                 add_url_alias(ret, name);
 696         if (!valid_remote(ret))
 697                 return NULL;
 698         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 699         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 700         return ret;
 701 }
 702
 703 int remote_is_configured(const char *name)
 704 {
 705         int i;
 706         read_config();
 707
 708         for (i = 0; i < remotes_nr; i++)
 709                 if (!strcmp(name, remotes[i]->name))
 710                         return 1;
 711         return 0;
 712 }
 713
 714 int for_each_remote(each_remote_fn fn, void *priv)
 715 {
 716         int i, result = 0;
 717         read_config();
 718         for (i = 0; i < remotes_nr && !result; i++) {
 719                 struct remote *r = remotes[i];
 720                 if (!r)
 721                         continue;
 722                 if (!r->fetch)
 723                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 724                                                        r->fetch_refspec);
 725                 if (!r->push)
 726                         r->push = parse_push_refspec(r->push_refspec_nr,
 727                                                      r->push_refspec);
 728                 result = fn(r, priv);
 729         }
 730         return result;
 731 }
 732
 733 void ref_remove_duplicates(struct ref *ref_map)
 734 {
 735         struct string_list refs = STRING_LIST_INIT_NODUP;
 736         struct string_list_item *item = NULL;
 737         struct ref *prev = NULL, *next = NULL;
 738         for (; ref_map; prev = ref_map, ref_map = next) {
 739                 next = ref_map->next;
 740                 if (!ref_map->peer_ref)
 741                         continue;
 742
 743                 item = string_list_lookup(&refs, ref_map->peer_ref->name);
 744                 if (item) {
 745                         if (strcmp(((struct ref *)item->util)->name,
 746                                    ref_map->name))
 747                                 die("%s tracks both %s and %s",
 748                                     ref_map->peer_ref->name,
 749                                     ((struct ref *)item->util)->name,
 750                                     ref_map->name);
 751                         prev->next = ref_map->next;
 752                         free(ref_map->peer_ref);
 753                         free(ref_map);
 754                         ref_map = prev; /* skip this; we freed it */
 755                         continue;
 756                 }
 757
 758                 item = string_list_insert(&refs, ref_map->peer_ref->name);
 759                 item->util = ref_map;
 760         }
 761         string_list_clear(&refs, 0);
 762 }
 763
 764 int remote_has_url(struct remote *remote, const char *url)
 765 {
 766         int i;
 767         for (i = 0; i < remote->url_nr; i++) {
 768                 if (!strcmp(remote->url[i], url))
 769                         return 1;
 770         }
 771         return 0;
 772 }
 773
 774 static int match_name_with_pattern(const char *key, const char *name,
 775                                    const char *value, char **result)
 776 {
 777         const char *kstar = strchr(key, '*');
 778         size_t klen;
 779         size_t ksuffixlen;
 780         size_t namelen;
 781         int ret;
 782         if (!kstar)
 783                 die("Key '%s' of pattern had no '*'", key);
 784         klen = kstar - key;
 785         ksuffixlen = strlen(kstar + 1);
 786         namelen = strlen(name);
 787         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 788                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 789         if (ret && value) {
 790                 const char *vstar = strchr(value, '*');
 791                 size_t vlen;
 792                 size_t vsuffixlen;
 793                 if (!vstar)
 794                         die("Value '%s' of pattern has no '*'", value);
 795                 vlen = vstar - value;
 796                 vsuffixlen = strlen(vstar + 1);
 797                 *result = xmalloc(vlen + vsuffixlen +
 798                                   strlen(name) -
 799                                   klen - ksuffixlen + 1);
 800                 strncpy(*result, value, vlen);
 801                 strncpy(*result + vlen,
 802                         name + klen, namelen - klen - ksuffixlen);
 803                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
 804                        vstar + 1);
 805         }
 806         return ret;
 807 }
 808
 809 static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
 810 {
 811         int i;
 812         int find_src = !query->src;
 813
 814         if (find_src && !query->dst)
 815                 return error("query_refspecs: need either src or dst");
 816
 817         for (i = 0; i < ref_count; i++) {
 818                 struct refspec *refspec = &refs[i];
 819                 const char *key = find_src ? refspec->dst : refspec->src;
 820                 const char *value = find_src ? refspec->src : refspec->dst;
 821                 const char *needle = find_src ? query->dst : query->src;
 822                 char **result = find_src ? &query->src : &query->dst;
 823
 824                 if (!refspec->dst)
 825                         continue;
 826                 if (refspec->pattern) {
 827                         if (match_name_with_pattern(key, needle, value, result)) {
 828                                 query->force = refspec->force;
 829                                 return 0;
 830                         }
 831                 } else if (!strcmp(needle, key)) {
 832                         *result = xstrdup(value);
 833                         query->force = refspec->force;
 834                         return 0;
 835                 }
 836         }
 837         return -1;
 838 }
 839
 840 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 841                      const char *name)
 842 {
 843         struct refspec query;
 844
 845         memset(&query, 0, sizeof(struct refspec));
 846         query.src = (char *)name;
 847
 848         if (query_refspecs(refspecs, nr_refspec, &query))
 849                 return NULL;
 850
 851         return query.dst;
 852 }
 853
 854 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 855 {
 856         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
 857 }
 858
 859 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 860                 const char *name)
 861 {
 862         size_t len = strlen(name);
 863         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 864         memcpy(ref->name, prefix, prefixlen);
 865         memcpy(ref->name + prefixlen, name, len);
 866         return ref;
 867 }
 868
 869 struct ref *alloc_ref(const char *name)
 870 {
 871         return alloc_ref_with_prefix("", 0, name);
 872 }
 873
 874 struct ref *copy_ref(const struct ref *ref)
 875 {
 876         struct ref *cpy;
 877         size_t len;
 878         if (!ref)
 879                 return NULL;
 880         len = strlen(ref->name);
 881         cpy = xmalloc(sizeof(struct ref) + len + 1);
 882         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 883         cpy->next = NULL;
 884         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 885         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 886         cpy->peer_ref = copy_ref(ref->peer_ref);
 887         return cpy;
 888 }
 889
 890 struct ref *copy_ref_list(const struct ref *ref)
 891 {
 892         struct ref *ret = NULL;
 893         struct ref **tail = &ret;
 894         while (ref) {
 895                 *tail = copy_ref(ref);
 896                 ref = ref->next;
 897                 tail = &((*tail)->next);
 898         }
 899         return ret;
 900 }
 901
 902 static void free_ref(struct ref *ref)
 903 {
 904         if (!ref)
 905                 return;
 906         free_ref(ref->peer_ref);
 907         free(ref->remote_status);
 908         free(ref->symref);
 909         free(ref);
 910 }
 911
 912 void free_refs(struct ref *ref)
 913 {
 914         struct ref *next;
 915         while (ref) {
 916                 next = ref->next;
 917                 free_ref(ref);
 918                 ref = next;
 919         }
 920 }
 921
 922 int ref_compare_name(const void *va, const void *vb)
 923 {
 924         const struct ref *a = va, *b = vb;
 925         return strcmp(a->name, b->name);
 926 }
 927
 928 static void *ref_list_get_next(const void *a)
 929 {
 930         return ((const struct ref *)a)->next;
 931 }
 932
 933 static void ref_list_set_next(void *a, void *next)
 934 {
 935         ((struct ref *)a)->next = next;
 936 }
 937
 938 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
 939 {
 940         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
 941 }
 942
 943 static int count_refspec_match(const char *pattern,
 944                                struct ref *refs,
 945                                struct ref **matched_ref)
 946 {
 947         int patlen = strlen(pattern);
 948         struct ref *matched_weak = NULL;
 949         struct ref *matched = NULL;
 950         int weak_match = 0;
 951         int match = 0;
 952
 953         for (weak_match = match = 0; refs; refs = refs->next) {
 954                 char *name = refs->name;
 955                 int namelen = strlen(name);
 956
 957                 if (!refname_match(pattern, name, ref_rev_parse_rules))
 958                         continue;
 959
 960                 /* A match is "weak" if it is with refs outside
 961                  * heads or tags, and did not specify the pattern
 962                  * in full (e.g. "refs/remotes/origin/master") or at
 963                  * least from the toplevel (e.g. "remotes/origin/master");
 964                  * otherwise "git push $URL master" would result in
 965                  * ambiguity between remotes/origin/master and heads/master
 966                  * at the remote site.
 967                  */
 968                 if (namelen != patlen &&
 969                     patlen != namelen - 5 &&
 970                     prefixcmp(name, "refs/heads/") &&
 971                     prefixcmp(name, "refs/tags/")) {
 972                         /* We want to catch the case where only weak
 973                          * matches are found and there are multiple
 974                          * matches, and where more than one strong
 975                          * matches are found, as ambiguous.  One
 976                          * strong match with zero or more weak matches
 977                          * are acceptable as a unique match.
 978                          */
 979                         matched_weak = refs;
 980                         weak_match++;
 981                 }
 982                 else {
 983                         matched = refs;
 984                         match++;
 985                 }
 986         }
 987         if (!matched) {
 988                 *matched_ref = matched_weak;
 989                 return weak_match;
 990         }
 991         else {
 992                 *matched_ref = matched;
 993                 return match;
 994         }
 995 }
 996
 997 static void tail_link_ref(struct ref *ref, struct ref ***tail)
 998 {
 999         **tail = ref;
1000         while (ref->next)
1001                 ref = ref->next;
1002         *tail = &ref->next;
1003 }
1004
1005 static struct ref *alloc_delete_ref(void)
1006 {
1007         struct ref *ref = alloc_ref("(delete)");
1008         hashclr(ref->new_sha1);
1009         return ref;
1010 }
1011
1012 static struct ref *try_explicit_object_name(const char *name)
1013 {
1014         unsigned char sha1[20];
1015         struct ref *ref;
1016
1017         if (!*name)
1018                 return alloc_delete_ref();
1019         if (get_sha1(name, sha1))
1020                 return NULL;
1021         ref = alloc_ref(name);
1022         hashcpy(ref->new_sha1, sha1);
1023         return ref;
1024 }
1025
1026 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1027 {
1028         struct ref *ret = alloc_ref(name);
1029         tail_link_ref(ret, tail);
1030         return ret;
1031 }
1032
1033 static char *guess_ref(const char *name, struct ref *peer)
1034 {
1035         struct strbuf buf = STRBUF_INIT;
1036         unsigned char sha1[20];
1037
1038         const char *r = resolve_ref_unsafe(peer->name, sha1, 1, NULL);
1039         if (!r)
1040                 return NULL;
1041
1042         if (!prefixcmp(r, "refs/heads/"))
1043                 strbuf_addstr(&buf, "refs/heads/");
1044         else if (!prefixcmp(r, "refs/tags/"))
1045                 strbuf_addstr(&buf, "refs/tags/");
1046         else
1047                 return NULL;
1048
1049         strbuf_addstr(&buf, name);
1050         return strbuf_detach(&buf, NULL);
1051 }
1052
1053 static int match_explicit(struct ref *src, struct ref *dst,
1054                           struct ref ***dst_tail,
1055                           struct refspec *rs)
1056 {
1057         struct ref *matched_src, *matched_dst;
1058         int copy_src;
1059
1060         const char *dst_value = rs->dst;
1061         char *dst_guess;
1062
1063         if (rs->pattern || rs->matching)
1064                 return 0;
1065
1066         matched_src = matched_dst = NULL;
1067         switch (count_refspec_match(rs->src, src, &matched_src)) {
1068         case 1:
1069                 copy_src = 1;
1070                 break;
1071         case 0:
1072                 /* The source could be in the get_sha1() format
1073                  * not a reference name.  :refs/other is a
1074                  * way to delete 'other' ref at the remote end.
1075                  */
1076                 matched_src = try_explicit_object_name(rs->src);
1077                 if (!matched_src)
1078                         return error("src refspec %s does not match any.", rs->src);
1079                 copy_src = 0;
1080                 break;
1081         default:
1082                 return error("src refspec %s matches more than one.", rs->src);
1083         }
1084
1085         if (!dst_value) {
1086                 unsigned char sha1[20];
1087                 int flag;
1088
1089                 dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
1090                 if (!dst_value ||
1091                     ((flag & REF_ISSYMREF) &&
1092                      prefixcmp(dst_value, "refs/heads/")))
1093                         die("%s cannot be resolved to branch.",
1094                             matched_src->name);
1095         }
1096
1097         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1098         case 1:
1099                 break;
1100         case 0:
1101                 if (!memcmp(dst_value, "refs/", 5))
1102                         matched_dst = make_linked_ref(dst_value, dst_tail);
1103                 else if (is_null_sha1(matched_src->new_sha1))
1104                         error("unable to delete '%s': remote ref does not exist",
1105                               dst_value);
1106                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1107                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1108                 else
1109                         error("unable to push to unqualified destination: %s\n"
1110                               "The destination refspec neither matches an "
1111                               "existing ref on the remote nor\n"
1112                               "begins with refs/, and we are unable to "
1113                               "guess a prefix based on the source ref.",
1114                               dst_value);
1115                 break;
1116         default:
1117                 matched_dst = NULL;
1118                 error("dst refspec %s matches more than one.",
1119                       dst_value);
1120                 break;
1121         }
1122         if (!matched_dst)
1123                 return -1;
1124         if (matched_dst->peer_ref)
1125                 return error("dst ref %s receives from more than one src.",
1126                       matched_dst->name);
1127         else {
1128                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1129                 matched_dst->force = rs->force;
1130         }
1131         return 0;
1132 }
1133
1134 static int match_explicit_refs(struct ref *src, struct ref *dst,
1135                                struct ref ***dst_tail, struct refspec *rs,
1136                                int rs_nr)
1137 {
1138         int i, errs;
1139         for (i = errs = 0; i < rs_nr; i++)
1140                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1141         return errs;
1142 }
1143
1144 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1145                 int send_mirror, int direction, const struct refspec **ret_pat)
1146 {
1147         const struct refspec *pat;
1148         char *name;
1149         int i;
1150         int matching_refs = -1;
1151         for (i = 0; i < rs_nr; i++) {
1152                 if (rs[i].matching &&
1153                     (matching_refs == -1 || rs[i].force)) {
1154                         matching_refs = i;
1155                         continue;
1156                 }
1157
1158                 if (rs[i].pattern) {
1159                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1160                         int match;
1161                         if (direction == FROM_SRC)
1162                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1163                         else
1164                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1165                         if (match) {
1166                                 matching_refs = i;
1167                                 break;
1168                         }
1169                 }
1170         }
1171         if (matching_refs == -1)
1172                 return NULL;
1173
1174         pat = rs + matching_refs;
1175         if (pat->matching) {
1176                 /*
1177                  * "matching refs"; traditionally we pushed everything
1178                  * including refs outside refs/heads/ hierarchy, but
1179                  * that does not make much sense these days.
1180                  */
1181                 if (!send_mirror && prefixcmp(ref->name, "refs/heads/"))
1182                         return NULL;
1183                 name = xstrdup(ref->name);
1184         }
1185         if (ret_pat)
1186                 *ret_pat = pat;
1187         return name;
1188 }
1189
1190 static struct ref **tail_ref(struct ref **head)
1191 {
1192         struct ref **tail = head;
1193         while (*tail)
1194                 tail = &((*tail)->next);
1195         return tail;
1196 }
1197
1198 /*
1199  * Given the set of refs the local repository has, the set of refs the
1200  * remote repository has, and the refspec used for push, determine
1201  * what remote refs we will update and with what value by setting
1202  * peer_ref (which object is being pushed) and force (if the push is
1203  * forced) in elements of "dst". The function may add new elements to
1204  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1205  */
1206 int match_push_refs(struct ref *src, struct ref **dst,
1207                     int nr_refspec, const char **refspec, int flags)
1208 {
1209         struct refspec *rs;
1210         int send_all = flags & MATCH_REFS_ALL;
1211         int send_mirror = flags & MATCH_REFS_MIRROR;
1212         int send_prune = flags & MATCH_REFS_PRUNE;
1213         int errs;
1214         static const char *default_refspec[] = { ":", NULL };
1215         struct ref *ref, **dst_tail = tail_ref(dst);
1216
1217         if (!nr_refspec) {
1218                 nr_refspec = 1;
1219                 refspec = default_refspec;
1220         }
1221         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1222         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1223
1224         /* pick the remainder */
1225         for (ref = src; ref; ref = ref->next) {
1226                 struct ref *dst_peer;
1227                 const struct refspec *pat = NULL;
1228                 char *dst_name;
1229
1230                 if (ref->peer_ref)
1231                         continue;
1232
1233                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1234                 if (!dst_name)
1235                         continue;
1236
1237                 dst_peer = find_ref_by_name(*dst, dst_name);
1238                 if (dst_peer) {
1239                         if (dst_peer->peer_ref)
1240                                 /* We're already sending something to this ref. */
1241                                 goto free_name;
1242                 } else {
1243                         if (pat->matching && !(send_all || send_mirror))
1244                                 /*
1245                                  * Remote doesn't have it, and we have no
1246                                  * explicit pattern, and we don't have
1247                                  * --all nor --mirror.
1248                                  */
1249                                 goto free_name;
1250
1251                         /* Create a new one and link it */
1252                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1253                         hashcpy(dst_peer->new_sha1, ref->new_sha1);
1254                 }
1255                 dst_peer->peer_ref = copy_ref(ref);
1256                 dst_peer->force = pat->force;
1257         free_name:
1258                 free(dst_name);
1259         }
1260         if (send_prune) {
1261                 /* check for missing refs on the remote */
1262                 for (ref = *dst; ref; ref = ref->next) {
1263                         char *src_name;
1264
1265                         if (ref->peer_ref)
1266                                 /* We're already sending something to this ref. */
1267                                 continue;
1268
1269                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1270                         if (src_name) {
1271                                 if (!find_ref_by_name(src, src_name))
1272                                         ref->peer_ref = alloc_delete_ref();
1273                                 free(src_name);
1274                         }
1275                 }
1276         }
1277         if (errs)
1278                 return -1;
1279         return 0;
1280 }
1281
1282 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1283         int force_update)
1284 {
1285         struct ref *ref;
1286
1287         for (ref = remote_refs; ref; ref = ref->next) {
1288                 int force_ref_update = ref->force || force_update;
1289
1290                 if (ref->peer_ref)
1291                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1292                 else if (!send_mirror)
1293                         continue;
1294
1295                 ref->deletion = is_null_sha1(ref->new_sha1);
1296                 if (!ref->deletion &&
1297                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1298                         ref->status = REF_STATUS_UPTODATE;
1299                         continue;
1300                 }
1301
1302                 /*
1303                  * Decide whether an individual refspec A:B can be
1304                  * pushed.  The push will succeed if any of the
1305                  * following are true:
1306                  *
1307                  * (1) the remote reference B does not exist
1308                  *
1309                  * (2) the remote reference B is being removed (i.e.,
1310                  *     pushing :B where no source is specified)
1311                  *
1312                  * (3) the destination is not under refs/tags/, and
1313                  *     if the old and new value is a commit, the new
1314                  *     is a descendant of the old.
1315                  *
1316                  * (4) it is forced using the +A:B notation, or by
1317                  *     passing the --force argument
1318                  */
1319
1320                 if (!ref->deletion && !is_null_sha1(ref->old_sha1)) {
1321                         int why = 0; /* why would this push require --force? */
1322
1323                         if (!prefixcmp(ref->name, "refs/tags/"))
1324                                 why = REF_STATUS_REJECT_ALREADY_EXISTS;
1325                         else if (!has_sha1_file(ref->old_sha1))
1326                                 why = REF_STATUS_REJECT_FETCH_FIRST;
1327                         else if (!lookup_commit_reference_gently(ref->old_sha1, 1) ||
1328                                  !lookup_commit_reference_gently(ref->new_sha1, 1))
1329                                 why = REF_STATUS_REJECT_NEEDS_FORCE;
1330                         else if (!ref_newer(ref->new_sha1, ref->old_sha1))
1331                                 why = REF_STATUS_REJECT_NONFASTFORWARD;
1332
1333                         if (!force_ref_update)
1334                                 ref->status = why;
1335                         else if (why)
1336                                 ref->forced_update = 1;
1337                 }
1338         }
1339 }
1340
1341 struct branch *branch_get(const char *name)
1342 {
1343         struct branch *ret;
1344
1345         read_config();
1346         if (!name || !*name || !strcmp(name, "HEAD"))
1347                 ret = current_branch;
1348         else
1349                 ret = make_branch(name, 0);
1350         if (ret && ret->remote_name) {
1351                 ret->remote = remote_get(ret->remote_name);
1352                 if (ret->merge_nr) {
1353                         int i;
1354                         ret->merge = xcalloc(sizeof(*ret->merge),
1355                                              ret->merge_nr);
1356                         for (i = 0; i < ret->merge_nr; i++) {
1357                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1358                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1359                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1360                                     && !strcmp(ret->remote_name, "."))
1361                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1362                         }
1363                 }
1364         }
1365         return ret;
1366 }
1367
1368 int branch_has_merge_config(struct branch *branch)
1369 {
1370         return branch && !!branch->merge;
1371 }
1372
1373 int branch_merge_matches(struct branch *branch,
1374                                  int i,
1375                                  const char *refname)
1376 {
1377         if (!branch || i < 0 || i >= branch->merge_nr)
1378                 return 0;
1379         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1380 }
1381
1382 static int ignore_symref_update(const char *refname)
1383 {
1384         unsigned char sha1[20];
1385         int flag;
1386
1387         if (!resolve_ref_unsafe(refname, sha1, 0, &flag))
1388                 return 0; /* non-existing refs are OK */
1389         return (flag & REF_ISSYMREF);
1390 }
1391
1392 static struct ref *get_expanded_map(const struct ref *remote_refs,
1393                                     const struct refspec *refspec)
1394 {
1395         const struct ref *ref;
1396         struct ref *ret = NULL;
1397         struct ref **tail = &ret;
1398
1399         char *expn_name;
1400
1401         for (ref = remote_refs; ref; ref = ref->next) {
1402                 if (strchr(ref->name, '^'))
1403                         continue; /* a dereference item */
1404                 if (match_name_with_pattern(refspec->src, ref->name,
1405                                             refspec->dst, &expn_name) &&
1406                     !ignore_symref_update(expn_name)) {
1407                         struct ref *cpy = copy_ref(ref);
1408
1409                         cpy->peer_ref = alloc_ref(expn_name);
1410                         free(expn_name);
1411                         if (refspec->force)
1412                                 cpy->peer_ref->force = 1;
1413                         *tail = cpy;
1414                         tail = &cpy->next;
1415                 }
1416         }
1417
1418         return ret;
1419 }
1420
1421 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1422 {
1423         const struct ref *ref;
1424         for (ref = refs; ref; ref = ref->next) {
1425                 if (refname_match(name, ref->name, ref_fetch_rules))
1426                         return ref;
1427         }
1428         return NULL;
1429 }
1430
1431 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1432 {
1433         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1434
1435         if (!ref)
1436                 return NULL;
1437
1438         return copy_ref(ref);
1439 }
1440
1441 static struct ref *get_local_ref(const char *name)
1442 {
1443         if (!name || name[0] == '\0')
1444                 return NULL;
1445
1446         if (!prefixcmp(name, "refs/"))
1447                 return alloc_ref(name);
1448
1449         if (!prefixcmp(name, "heads/") ||
1450             !prefixcmp(name, "tags/") ||
1451             !prefixcmp(name, "remotes/"))
1452                 return alloc_ref_with_prefix("refs/", 5, name);
1453
1454         return alloc_ref_with_prefix("refs/heads/", 11, name);
1455 }
1456
1457 int get_fetch_map(const struct ref *remote_refs,
1458                   const struct refspec *refspec,
1459                   struct ref ***tail,
1460                   int missing_ok)
1461 {
1462         struct ref *ref_map, **rmp;
1463
1464         if (refspec->pattern) {
1465                 ref_map = get_expanded_map(remote_refs, refspec);
1466         } else {
1467                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1468
1469                 ref_map = get_remote_ref(remote_refs, name);
1470                 if (!missing_ok && !ref_map)
1471                         die("Couldn't find remote ref %s", name);
1472                 if (ref_map) {
1473                         ref_map->peer_ref = get_local_ref(refspec->dst);
1474                         if (ref_map->peer_ref && refspec->force)
1475                                 ref_map->peer_ref->force = 1;
1476                 }
1477         }
1478
1479         for (rmp = &ref_map; *rmp; ) {
1480                 if ((*rmp)->peer_ref) {
1481                         if (prefixcmp((*rmp)->peer_ref->name, "refs/") ||
1482                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1483                                 struct ref *ignore = *rmp;
1484                                 error("* Ignoring funny ref '%s' locally",
1485                                       (*rmp)->peer_ref->name);
1486                                 *rmp = (*rmp)->next;
1487                                 free(ignore->peer_ref);
1488                                 free(ignore);
1489                                 continue;
1490                         }
1491                 }
1492                 rmp = &((*rmp)->next);
1493         }
1494
1495         if (ref_map)
1496                 tail_link_ref(ref_map, tail);
1497
1498         return 0;
1499 }
1500
1501 int resolve_remote_symref(struct ref *ref, struct ref *list)
1502 {
1503         if (!ref->symref)
1504                 return 0;
1505         for (; list; list = list->next)
1506                 if (!strcmp(ref->symref, list->name)) {
1507                         hashcpy(ref->old_sha1, list->old_sha1);
1508                         return 0;
1509                 }
1510         return 1;
1511 }
1512
1513 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1514 {
1515         while (list) {
1516                 struct commit_list *temp = list;
1517                 temp->item->object.flags &= ~mark;
1518                 list = temp->next;
1519                 free(temp);
1520         }
1521 }
1522
1523 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1524 {
1525         struct object *o;
1526         struct commit *old, *new;
1527         struct commit_list *list, *used;
1528         int found = 0;
1529
1530         /*
1531          * Both new and old must be commit-ish and new is descendant of
1532          * old.  Otherwise we require --force.
1533          */
1534         o = deref_tag(parse_object(old_sha1), NULL, 0);
1535         if (!o || o->type != OBJ_COMMIT)
1536                 return 0;
1537         old = (struct commit *) o;
1538
1539         o = deref_tag(parse_object(new_sha1), NULL, 0);
1540         if (!o || o->type != OBJ_COMMIT)
1541                 return 0;
1542         new = (struct commit *) o;
1543
1544         if (parse_commit(new) < 0)
1545                 return 0;
1546
1547         used = list = NULL;
1548         commit_list_insert(new, &list);
1549         while (list) {
1550                 new = pop_most_recent_commit(&list, TMP_MARK);
1551                 commit_list_insert(new, &used);
1552                 if (new == old) {
1553                         found = 1;
1554                         break;
1555                 }
1556         }
1557         unmark_and_free(list, TMP_MARK);
1558         unmark_and_free(used, TMP_MARK);
1559         return found;
1560 }
1561
1562 /*
1563  * Return true if there is anything to report, otherwise false.
1564  */
1565 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1566 {
1567         unsigned char sha1[20];
1568         struct commit *ours, *theirs;
1569         char symmetric[84];
1570         struct rev_info revs;
1571         const char *rev_argv[10], *base;
1572         int rev_argc;
1573
1574         /*
1575          * Nothing to report unless we are marked to build on top of
1576          * somebody else.
1577          */
1578         if (!branch ||
1579             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1580                 return 0;
1581
1582         /*
1583          * If what we used to build on no longer exists, there is
1584          * nothing to report.
1585          */
1586         base = branch->merge[0]->dst;
1587         if (read_ref(base, sha1))
1588                 return 0;
1589         theirs = lookup_commit_reference(sha1);
1590         if (!theirs)
1591                 return 0;
1592
1593         if (read_ref(branch->refname, sha1))
1594                 return 0;
1595         ours = lookup_commit_reference(sha1);
1596         if (!ours)
1597                 return 0;
1598
1599         /* are we the same? */
1600         if (theirs == ours)
1601                 return 0;
1602
1603         /* Run "rev-list --left-right ours...theirs" internally... */
1604         rev_argc = 0;
1605         rev_argv[rev_argc++] = NULL;
1606         rev_argv[rev_argc++] = "--left-right";
1607         rev_argv[rev_argc++] = symmetric;
1608         rev_argv[rev_argc++] = "--";
1609         rev_argv[rev_argc] = NULL;
1610
1611         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1612         strcpy(symmetric + 40, "...");
1613         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1614
1615         init_revisions(&revs, NULL);
1616         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1617         prepare_revision_walk(&revs);
1618
1619         /* ... and count the commits on each side. */
1620         *num_ours = 0;
1621         *num_theirs = 0;
1622         while (1) {
1623                 struct commit *c = get_revision(&revs);
1624                 if (!c)
1625                         break;
1626                 if (c->object.flags & SYMMETRIC_LEFT)
1627                         (*num_ours)++;
1628                 else
1629                         (*num_theirs)++;
1630         }
1631
1632         /* clear object flags smudged by the above traversal */
1633         clear_commit_marks(ours, ALL_REV_FLAGS);
1634         clear_commit_marks(theirs, ALL_REV_FLAGS);
1635         return 1;
1636 }
1637
1638 /*
1639  * Return true when there is anything to report, otherwise false.
1640  */
1641 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1642 {
1643         int num_ours, num_theirs;
1644         const char *base;
1645
1646         if (!stat_tracking_info(branch, &num_ours, &num_theirs))
1647                 return 0;
1648
1649         base = branch->merge[0]->dst;
1650         base = shorten_unambiguous_ref(base, 0);
1651         if (!num_theirs) {
1652                 strbuf_addf(sb,
1653                         Q_("Your branch is ahead of '%s' by %d commit.\n",
1654                            "Your branch is ahead of '%s' by %d commits.\n",
1655                            num_ours),
1656                         base, num_ours);
1657                 if (advice_status_hints)
1658                         strbuf_addf(sb,
1659                                 _("  (use \"git push\" to publish your local commits)\n"));
1660         } else if (!num_ours) {
1661                 strbuf_addf(sb,
1662                         Q_("Your branch is behind '%s' by %d commit, "
1663                                "and can be fast-forwarded.\n",
1664                            "Your branch is behind '%s' by %d commits, "
1665                                "and can be fast-forwarded.\n",
1666                            num_theirs),
1667                         base, num_theirs);
1668                 if (advice_status_hints)
1669                         strbuf_addf(sb,
1670                                 _("  (use \"git pull\" to update your local branch)\n"));
1671         } else {
1672                 strbuf_addf(sb,
1673                         Q_("Your branch and '%s' have diverged,\n"
1674                                "and have %d and %d different commit each, "
1675                                "respectively.\n",
1676                            "Your branch and '%s' have diverged,\n"
1677                                "and have %d and %d different commits each, "
1678                                "respectively.\n",
1679                            num_theirs),
1680                         base, num_ours, num_theirs);
1681                 if (advice_status_hints)
1682                         strbuf_addf(sb,
1683                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
1684         }
1685         return 1;
1686 }
1687
1688 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1689 {
1690         struct ref ***local_tail = cb_data;
1691         struct ref *ref;
1692         int len;
1693
1694         /* we already know it starts with refs/ to get here */
1695         if (check_refname_format(refname + 5, 0))
1696                 return 0;
1697
1698         len = strlen(refname) + 1;
1699         ref = xcalloc(1, sizeof(*ref) + len);
1700         hashcpy(ref->new_sha1, sha1);
1701         memcpy(ref->name, refname, len);
1702         **local_tail = ref;
1703         *local_tail = &ref->next;
1704         return 0;
1705 }
1706
1707 struct ref *get_local_heads(void)
1708 {
1709         struct ref *local_refs = NULL, **local_tail = &local_refs;
1710         for_each_ref(one_local_ref, &local_tail);
1711         return local_refs;
1712 }
1713
1714 struct ref *guess_remote_head(const struct ref *head,
1715                               const struct ref *refs,
1716                               int all)
1717 {
1718         const struct ref *r;
1719         struct ref *list = NULL;
1720         struct ref **tail = &list;
1721
1722         if (!head)
1723                 return NULL;
1724
1725         /*
1726          * Some transports support directly peeking at
1727          * where HEAD points; if that is the case, then
1728          * we don't have to guess.
1729          */
1730         if (head->symref)
1731                 return copy_ref(find_ref_by_name(refs, head->symref));
1732
1733         /* If refs/heads/master could be right, it is. */
1734         if (!all) {
1735                 r = find_ref_by_name(refs, "refs/heads/master");
1736                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1737                         return copy_ref(r);
1738         }
1739
1740         /* Look for another ref that points there */
1741         for (r = refs; r; r = r->next) {
1742                 if (r != head &&
1743                     !prefixcmp(r->name, "refs/heads/") &&
1744                     !hashcmp(r->old_sha1, head->old_sha1)) {
1745                         *tail = copy_ref(r);
1746                         tail = &((*tail)->next);
1747                         if (!all)
1748                                 break;
1749                 }
1750         }
1751
1752         return list;
1753 }
1754
1755 struct stale_heads_info {
1756         struct string_list *ref_names;
1757         struct ref **stale_refs_tail;
1758         struct refspec *refs;
1759         int ref_count;
1760 };
1761
1762 static int get_stale_heads_cb(const char *refname,
1763         const unsigned char *sha1, int flags, void *cb_data)
1764 {
1765         struct stale_heads_info *info = cb_data;
1766         struct refspec query;
1767         memset(&query, 0, sizeof(struct refspec));
1768         query.dst = (char *)refname;
1769
1770         if (query_refspecs(info->refs, info->ref_count, &query))
1771                 return 0; /* No matches */
1772
1773         /*
1774          * If we did find a suitable refspec and it's not a symref and
1775          * it's not in the list of refs that currently exist in that
1776          * remote we consider it to be stale.
1777          */
1778         if (!((flags & REF_ISSYMREF) ||
1779               string_list_has_string(info->ref_names, query.src))) {
1780                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
1781                 hashcpy(ref->new_sha1, sha1);
1782         }
1783
1784         free(query.src);
1785         return 0;
1786 }
1787
1788 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
1789 {
1790         struct ref *ref, *stale_refs = NULL;
1791         struct string_list ref_names = STRING_LIST_INIT_NODUP;
1792         struct stale_heads_info info;
1793         info.ref_names = &ref_names;
1794         info.stale_refs_tail = &stale_refs;
1795         info.refs = refs;
1796         info.ref_count = ref_count;
1797         for (ref = fetch_map; ref; ref = ref->next)
1798                 string_list_append(&ref_names, ref->name);
1799         sort_string_list(&ref_names);
1800         for_each_ref(get_stale_heads_cb, &info);
1801         string_list_clear(&ref_names, 0);
1802         return stale_refs;
1803 }