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