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