remote.c

   1 #include "cache.h"
   2 #include "remote.h"
   3 #include "refs.h"
   4 #include "commit.h"
   5 #include "diff.h"
   6 #include "revision.h"
   7 #include "dir.h"
   8 #include "tag.h"
   9 #include "string-list.h"
  10 #include "mergesort.h"
  11
  12 enum map_direction { FROM_SRC, FROM_DST };
  13
  14 static struct refspec s_tag_refspec = {
  15         0,
  16         1,
  17         0,
  18         0,
  19         "refs/tags/*",
  20         "refs/tags/*"
  21 };
  22
  23 const struct refspec *tag_refspec = &s_tag_refspec;
  24
  25 struct counted_string {
  26         size_t len;
  27         const char *s;
  28 };
  29 struct rewrite {
  30         const char *base;
  31         size_t baselen;
  32         struct counted_string *instead_of;
  33         int instead_of_nr;
  34         int instead_of_alloc;
  35 };
  36 struct rewrites {
  37         struct rewrite **rewrite;
  38         int rewrite_alloc;
  39         int rewrite_nr;
  40 };
  41
  42 static struct remote **remotes;
  43 static int remotes_alloc;
  44 static int remotes_nr;
  45
  46 static struct branch **branches;
  47 static int branches_alloc;
  48 static int branches_nr;
  49
  50 static struct branch *current_branch;
  51 static const char *default_remote_name;
  52 static int explicit_default_remote_name;
  53
  54 static struct rewrites rewrites;
  55 static struct rewrites rewrites_push;
  56
  57 #define BUF_SIZE (2048)
  58 static char buffer[BUF_SIZE];
  59
  60 static int valid_remote(const struct remote *remote)
  61 {
  62         return (!!remote->url) || (!!remote->foreign_vcs);
  63 }
  64
  65 static const char *alias_url(const char *url, struct rewrites *r)
  66 {
  67         int i, j;
  68         char *ret;
  69         struct counted_string *longest;
  70         int longest_i;
  71
  72         longest = NULL;
  73         longest_i = -1;
  74         for (i = 0; i < r->rewrite_nr; i++) {
  75                 if (!r->rewrite[i])
  76                         continue;
  77                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  78                         if (!prefixcmp(url, r->rewrite[i]->instead_of[j].s) &&
  79                             (!longest ||
  80                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  81                                 longest = &(r->rewrite[i]->instead_of[j]);
  82                                 longest_i = i;
  83                         }
  84                 }
  85         }
  86         if (!longest)
  87                 return url;
  88
  89         ret = xmalloc(r->rewrite[longest_i]->baselen +
  90                      (strlen(url) - longest->len) + 1);
  91         strcpy(ret, r->rewrite[longest_i]->base);
  92         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
  93         return ret;
  94 }
  95
  96 static void add_push_refspec(struct remote *remote, const char *ref)
  97 {
  98         ALLOC_GROW(remote->push_refspec,
  99                    remote->push_refspec_nr + 1,
 100                    remote->push_refspec_alloc);
 101         remote->push_refspec[remote->push_refspec_nr++] = ref;
 102 }
 103
 104 static void add_fetch_refspec(struct remote *remote, const char *ref)
 105 {
 106         ALLOC_GROW(remote->fetch_refspec,
 107                    remote->fetch_refspec_nr + 1,
 108                    remote->fetch_refspec_alloc);
 109         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
 110 }
 111
 112 static void add_url(struct remote *remote, const char *url)
 113 {
 114         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
 115         remote->url[remote->url_nr++] = url;
 116 }
 117
 118 static void add_pushurl(struct remote *remote, const char *pushurl)
 119 {
 120         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
 121         remote->pushurl[remote->pushurl_nr++] = pushurl;
 122 }
 123
 124 static void add_pushurl_alias(struct remote *remote, const char *url)
 125 {
 126         const char *pushurl = alias_url(url, &rewrites_push);
 127         if (pushurl != url)
 128                 add_pushurl(remote, pushurl);
 129 }
 130
 131 static void add_url_alias(struct remote *remote, const char *url)
 132 {
 133         add_url(remote, alias_url(url, &rewrites));
 134         add_pushurl_alias(remote, url);
 135 }
 136
 137 static struct remote *make_remote(const char *name, int len)
 138 {
 139         struct remote *ret;
 140         int i;
 141
 142         for (i = 0; i < remotes_nr; i++) {
 143                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
 144                            !remotes[i]->name[len]) :
 145                     !strcmp(name, remotes[i]->name))
 146                         return remotes[i];
 147         }
 148
 149         ret = xcalloc(1, sizeof(struct remote));
 150         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 151         remotes[remotes_nr++] = ret;
 152         if (len)
 153                 ret->name = xstrndup(name, len);
 154         else
 155                 ret->name = xstrdup(name);
 156         return ret;
 157 }
 158
 159 static void add_merge(struct branch *branch, const char *name)
 160 {
 161         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 162                    branch->merge_alloc);
 163         branch->merge_name[branch->merge_nr++] = name;
 164 }
 165
 166 static struct branch *make_branch(const char *name, int len)
 167 {
 168         struct branch *ret;
 169         int i;
 170         char *refname;
 171
 172         for (i = 0; i < branches_nr; i++) {
 173                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 174                            !branches[i]->name[len]) :
 175                     !strcmp(name, branches[i]->name))
 176                         return branches[i];
 177         }
 178
 179         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 180         ret = xcalloc(1, sizeof(struct branch));
 181         branches[branches_nr++] = ret;
 182         if (len)
 183                 ret->name = xstrndup(name, len);
 184         else
 185                 ret->name = xstrdup(name);
 186         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
 187         strcpy(refname, "refs/heads/");
 188         strcpy(refname + strlen("refs/heads/"), ret->name);
 189         ret->refname = refname;
 190
 191         return ret;
 192 }
 193
 194 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 195 {
 196         struct rewrite *ret;
 197         int i;
 198
 199         for (i = 0; i < r->rewrite_nr; i++) {
 200                 if (len
 201                     ? (len == r->rewrite[i]->baselen &&
 202                        !strncmp(base, r->rewrite[i]->base, len))
 203                     : !strcmp(base, r->rewrite[i]->base))
 204                         return r->rewrite[i];
 205         }
 206
 207         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 208         ret = xcalloc(1, sizeof(struct rewrite));
 209         r->rewrite[r->rewrite_nr++] = ret;
 210         if (len) {
 211                 ret->base = xstrndup(base, len);
 212                 ret->baselen = len;
 213         }
 214         else {
 215                 ret->base = xstrdup(base);
 216                 ret->baselen = strlen(base);
 217         }
 218         return ret;
 219 }
 220
 221 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 222 {
 223         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 224         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 225         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 226         rewrite->instead_of_nr++;
 227 }
 228
 229 static void read_remotes_file(struct remote *remote)
 230 {
 231         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 232
 233         if (!f)
 234                 return;
 235         remote->origin = REMOTE_REMOTES;
 236         while (fgets(buffer, BUF_SIZE, f)) {
 237                 int value_list;
 238                 char *s, *p;
 239
 240                 if (!prefixcmp(buffer, "URL:")) {
 241                         value_list = 0;
 242                         s = buffer + 4;
 243                 } else if (!prefixcmp(buffer, "Push:")) {
 244                         value_list = 1;
 245                         s = buffer + 5;
 246                 } else if (!prefixcmp(buffer, "Pull:")) {
 247                         value_list = 2;
 248                         s = buffer + 5;
 249                 } else
 250                         continue;
 251
 252                 while (isspace(*s))
 253                         s++;
 254                 if (!*s)
 255                         continue;
 256
 257                 p = s + strlen(s);
 258                 while (isspace(p[-1]))
 259                         *--p = 0;
 260
 261                 switch (value_list) {
 262                 case 0:
 263                         add_url_alias(remote, xstrdup(s));
 264                         break;
 265                 case 1:
 266                         add_push_refspec(remote, xstrdup(s));
 267                         break;
 268                 case 2:
 269                         add_fetch_refspec(remote, xstrdup(s));
 270                         break;
 271                 }
 272         }
 273         fclose(f);
 274 }
 275
 276 static void read_branches_file(struct remote *remote)
 277 {
 278         const char *slash = strchr(remote->name, '/');
 279         char *frag;
 280         struct strbuf branch = STRBUF_INIT;
 281         int n = slash ? slash - remote->name : 1000;
 282         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
 283         char *s, *p;
 284         int len;
 285
 286         if (!f)
 287                 return;
 288         s = fgets(buffer, BUF_SIZE, f);
 289         fclose(f);
 290         if (!s)
 291                 return;
 292         while (isspace(*s))
 293                 s++;
 294         if (!*s)
 295                 return;
 296         remote->origin = REMOTE_BRANCHES;
 297         p = s + strlen(s);
 298         while (isspace(p[-1]))
 299                 *--p = 0;
 300         len = p - s;
 301         if (slash)
 302                 len += strlen(slash);
 303         p = xmalloc(len + 1);
 304         strcpy(p, s);
 305         if (slash)
 306                 strcat(p, slash);
 307
 308         /*
 309          * With "slash", e.g. "git fetch jgarzik/netdev-2.6" when
 310          * reading from $GIT_DIR/branches/jgarzik fetches "HEAD" from
 311          * the partial URL obtained from the branches file plus
 312          * "/netdev-2.6" and does not store it in any tracking ref.
 313          * #branch specifier in the file is ignored.
 314          *
 315          * Otherwise, the branches file would have URL and optionally
 316          * #branch specified.  The "master" (or specified) branch is
 317          * fetched and stored in the local branch of the same name.
 318          */
 319         frag = strchr(p, '#');
 320         if (frag) {
 321                 *(frag++) = '\0';
 322                 strbuf_addf(&branch, "refs/heads/%s", frag);
 323         } else
 324                 strbuf_addstr(&branch, "refs/heads/master");
 325         if (!slash) {
 326                 strbuf_addf(&branch, ":refs/heads/%s", remote->name);
 327         } else {
 328                 strbuf_reset(&branch);
 329                 strbuf_addstr(&branch, "HEAD:");
 330         }
 331         add_url_alias(remote, p);
 332         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
 333         /*
 334          * Cogito compatible push: push current HEAD to remote #branch
 335          * (master if missing)
 336          */
 337         strbuf_init(&branch, 0);
 338         strbuf_addstr(&branch, "HEAD");
 339         if (frag)
 340                 strbuf_addf(&branch, ":refs/heads/%s", frag);
 341         else
 342                 strbuf_addstr(&branch, ":refs/heads/master");
 343         add_push_refspec(remote, strbuf_detach(&branch, NULL));
 344         remote->fetch_tags = 1; /* always auto-follow */
 345 }
 346
 347 static int handle_config(const char *key, const char *value, void *cb)
 348 {
 349         const char *name;
 350         const char *subkey;
 351         struct remote *remote;
 352         struct branch *branch;
 353         if (!prefixcmp(key, "branch.")) {
 354                 name = key + 7;
 355                 subkey = strrchr(name, '.');
 356                 if (!subkey)
 357                         return 0;
 358                 branch = make_branch(name, subkey - name);
 359                 if (!strcmp(subkey, ".remote")) {
 360                         if (git_config_string(&branch->remote_name, key, value))
 361                                 return -1;
 362                         if (branch == current_branch) {
 363                                 default_remote_name = branch->remote_name;
 364                                 explicit_default_remote_name = 1;
 365                         }
 366                 } else if (!strcmp(subkey, ".merge")) {
 367                         if (!value)
 368                                 return config_error_nonbool(key);
 369                         add_merge(branch, xstrdup(value));
 370                 }
 371                 return 0;
 372         }
 373         if (!prefixcmp(key, "url.")) {
 374                 struct rewrite *rewrite;
 375                 name = key + 4;
 376                 subkey = strrchr(name, '.');
 377                 if (!subkey)
 378                         return 0;
 379                 if (!strcmp(subkey, ".insteadof")) {
 380                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 381                         if (!value)
 382                                 return config_error_nonbool(key);
 383                         add_instead_of(rewrite, xstrdup(value));
 384                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 385                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 386                         if (!value)
 387                                 return config_error_nonbool(key);
 388                         add_instead_of(rewrite, xstrdup(value));
 389                 }
 390         }
 391         if (prefixcmp(key,  "remote."))
 392                 return 0;
 393         name = key + 7;
 394         if (*name == '/') {
 395                 warning("Config remote shorthand cannot begin with '/': %s",
 396                         name);
 397                 return 0;
 398         }
 399         subkey = strrchr(name, '.');
 400         if (!subkey)
 401                 return 0;
 402         remote = make_remote(name, subkey - name);
 403         remote->origin = REMOTE_CONFIG;
 404         if (!strcmp(subkey, ".mirror"))
 405                 remote->mirror = git_config_bool(key, value);
 406         else if (!strcmp(subkey, ".skipdefaultupdate"))
 407                 remote->skip_default_update = git_config_bool(key, value);
 408         else if (!strcmp(subkey, ".skipfetchall"))
 409                 remote->skip_default_update = git_config_bool(key, value);
 410         else if (!strcmp(subkey, ".url")) {
 411                 const char *v;
 412                 if (git_config_string(&v, key, value))
 413                         return -1;
 414                 add_url(remote, v);
 415         } else if (!strcmp(subkey, ".pushurl")) {
 416                 const char *v;
 417                 if (git_config_string(&v, key, value))
 418                         return -1;
 419                 add_pushurl(remote, v);
 420         } else if (!strcmp(subkey, ".push")) {
 421                 const char *v;
 422                 if (git_config_string(&v, key, value))
 423                         return -1;
 424                 add_push_refspec(remote, v);
 425         } else if (!strcmp(subkey, ".fetch")) {
 426                 const char *v;
 427                 if (git_config_string(&v, key, value))
 428                         return -1;
 429                 add_fetch_refspec(remote, v);
 430         } else if (!strcmp(subkey, ".receivepack")) {
 431                 const char *v;
 432                 if (git_config_string(&v, key, value))
 433                         return -1;
 434                 if (!remote->receivepack)
 435                         remote->receivepack = v;
 436                 else
 437                         error("more than one receivepack given, using the first");
 438         } else if (!strcmp(subkey, ".uploadpack")) {
 439                 const char *v;
 440                 if (git_config_string(&v, key, value))
 441                         return -1;
 442                 if (!remote->uploadpack)
 443                         remote->uploadpack = v;
 444                 else
 445                         error("more than one uploadpack given, using the first");
 446         } else if (!strcmp(subkey, ".tagopt")) {
 447                 if (!strcmp(value, "--no-tags"))
 448                         remote->fetch_tags = -1;
 449                 else if (!strcmp(value, "--tags"))
 450                         remote->fetch_tags = 2;
 451         } else if (!strcmp(subkey, ".proxy")) {
 452                 return git_config_string((const char **)&remote->http_proxy,
 453                                          key, value);
 454         } else if (!strcmp(subkey, ".vcs")) {
 455                 return git_config_string(&remote->foreign_vcs, key, value);
 456         }
 457         return 0;
 458 }
 459
 460 static void alias_all_urls(void)
 461 {
 462         int i, j;
 463         for (i = 0; i < remotes_nr; i++) {
 464                 int add_pushurl_aliases;
 465                 if (!remotes[i])
 466                         continue;
 467                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 468                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 469                 }
 470                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 471                 for (j = 0; j < remotes[i]->url_nr; j++) {
 472                         if (add_pushurl_aliases)
 473                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 474                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 475                 }
 476         }
 477 }
 478
 479 static void read_config(void)
 480 {
 481         unsigned char sha1[20];
 482         const char *head_ref;
 483         int flag;
 484         if (default_remote_name) /* did this already */
 485                 return;
 486         default_remote_name = xstrdup("origin");
 487         current_branch = NULL;
 488         head_ref = resolve_ref_unsafe("HEAD", sha1, 0, &flag);
 489         if (head_ref && (flag & REF_ISSYMREF) &&
 490             !prefixcmp(head_ref, "refs/heads/")) {
 491                 current_branch =
 492                         make_branch(head_ref + strlen("refs/heads/"), 0);
 493         }
 494         git_config(handle_config, NULL);
 495         alias_all_urls();
 496 }
 497
 498 /*
 499  * This function frees a refspec array.
 500  * Warning: code paths should be checked to ensure that the src
 501  *          and dst pointers are always freeable pointers as well
 502  *          as the refspec pointer itself.
 503  */
 504 static void free_refspecs(struct refspec *refspec, int nr_refspec)
 505 {
 506         int i;
 507
 508         if (!refspec)
 509                 return;
 510
 511         for (i = 0; i < nr_refspec; i++) {
 512                 free(refspec[i].src);
 513                 free(refspec[i].dst);
 514         }
 515         free(refspec);
 516 }
 517
 518 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 519 {
 520         int i;
 521         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 522
 523         for (i = 0; i < nr_refspec; i++) {
 524                 size_t llen;
 525                 int is_glob;
 526                 const char *lhs, *rhs;
 527                 int flags;
 528
 529                 is_glob = 0;
 530
 531                 lhs = refspec[i];
 532                 if (*lhs == '+') {
 533                         rs[i].force = 1;
 534                         lhs++;
 535                 }
 536
 537                 rhs = strrchr(lhs, ':');
 538
 539                 /*
 540                  * Before going on, special case ":" (or "+:") as a refspec
 541                  * for pushing matching refs.
 542                  */
 543                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
 544                         rs[i].matching = 1;
 545                         continue;
 546                 }
 547
 548                 if (rhs) {
 549                         size_t rlen = strlen(++rhs);
 550                         is_glob = (1 <= rlen && strchr(rhs, '*'));
 551                         rs[i].dst = xstrndup(rhs, rlen);
 552                 }
 553
 554                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 555                 if (1 <= llen && memchr(lhs, '*', llen)) {
 556                         if ((rhs && !is_glob) || (!rhs && fetch))
 557                                 goto invalid;
 558                         is_glob = 1;
 559                 } else if (rhs && is_glob) {
 560                         goto invalid;
 561                 }
 562
 563                 rs[i].pattern = is_glob;
 564                 rs[i].src = xstrndup(lhs, llen);
 565                 flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
 566
 567                 if (fetch) {
 568                         unsigned char unused[40];
 569
 570                         /* LHS */
 571                         if (!*rs[i].src)
 572                                 ; /* empty is ok; it means "HEAD" */
 573                         else if (llen == 40 && !get_sha1_hex(rs[i].src, unused))
 574                                 rs[i].exact_sha1 = 1; /* ok */
 575                         else if (!check_refname_format(rs[i].src, flags))
 576                                 ; /* valid looking ref is ok */
 577                         else
 578                                 goto invalid;
 579                         /* RHS */
 580                         if (!rs[i].dst)
 581                                 ; /* missing is ok; it is the same as empty */
 582                         else if (!*rs[i].dst)
 583                                 ; /* empty is ok; it means "do not store" */
 584                         else if (!check_refname_format(rs[i].dst, flags))
 585                                 ; /* valid looking ref is ok */
 586                         else
 587                                 goto invalid;
 588                 } else {
 589                         /*
 590                          * LHS
 591                          * - empty is allowed; it means delete.
 592                          * - when wildcarded, it must be a valid looking ref.
 593                          * - otherwise, it must be an extended SHA-1, but
 594                          *   there is no existing way to validate this.
 595                          */
 596                         if (!*rs[i].src)
 597                                 ; /* empty is ok */
 598                         else if (is_glob) {
 599                                 if (check_refname_format(rs[i].src, flags))
 600                                         goto invalid;
 601                         }
 602                         else
 603                                 ; /* anything goes, for now */
 604                         /*
 605                          * RHS
 606                          * - missing is allowed, but LHS then must be a
 607                          *   valid looking ref.
 608                          * - empty is not allowed.
 609                          * - otherwise it must be a valid looking ref.
 610                          */
 611                         if (!rs[i].dst) {
 612                                 if (check_refname_format(rs[i].src, flags))
 613                                         goto invalid;
 614                         } else if (!*rs[i].dst) {
 615                                 goto invalid;
 616                         } else {
 617                                 if (check_refname_format(rs[i].dst, flags))
 618                                         goto invalid;
 619                         }
 620                 }
 621         }
 622         return rs;
 623
 624  invalid:
 625         if (verify) {
 626                 /*
 627                  * nr_refspec must be greater than zero and i must be valid
 628                  * since it is only possible to reach this point from within
 629                  * the for loop above.
 630                  */
 631                 free_refspecs(rs, i+1);
 632                 return NULL;
 633         }
 634         die("Invalid refspec '%s'", refspec[i]);
 635 }
 636
 637 int valid_fetch_refspec(const char *fetch_refspec_str)
 638 {
 639         struct refspec *refspec;
 640
 641         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
 642         free_refspecs(refspec, 1);
 643         return !!refspec;
 644 }
 645
 646 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 647 {
 648         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 649 }
 650
 651 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 652 {
 653         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 654 }
 655
 656 void free_refspec(int nr_refspec, struct refspec *refspec)
 657 {
 658         int i;
 659         for (i = 0; i < nr_refspec; i++) {
 660                 free(refspec[i].src);
 661                 free(refspec[i].dst);
 662         }
 663         free(refspec);
 664 }
 665
 666 static int valid_remote_nick(const char *name)
 667 {
 668         if (!name[0] || is_dot_or_dotdot(name))
 669                 return 0;
 670         return !strchr(name, '/'); /* no slash */
 671 }
 672
 673 struct remote *remote_get(const char *name)
 674 {
 675         struct remote *ret;
 676         int name_given = 0;
 677
 678         read_config();
 679         if (name)
 680                 name_given = 1;
 681         else {
 682                 name = default_remote_name;
 683                 name_given = explicit_default_remote_name;
 684         }
 685
 686         ret = make_remote(name, 0);
 687         if (valid_remote_nick(name)) {
 688                 if (!valid_remote(ret))
 689                         read_remotes_file(ret);
 690                 if (!valid_remote(ret))
 691                         read_branches_file(ret);
 692         }
 693         if (name_given && !valid_remote(ret))
 694                 add_url_alias(ret, name);
 695         if (!valid_remote(ret))
 696                 return NULL;
 697         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 698         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 699         return ret;
 700 }
 701
 702 int remote_is_configured(const char *name)
 703 {
 704         int i;
 705         read_config();
 706
 707         for (i = 0; i < remotes_nr; i++)
 708                 if (!strcmp(name, remotes[i]->name))
 709                         return 1;
 710         return 0;
 711 }
 712
 713 int for_each_remote(each_remote_fn fn, void *priv)
 714 {
 715         int i, result = 0;
 716         read_config();
 717         for (i = 0; i < remotes_nr && !result; i++) {
 718                 struct remote *r = remotes[i];
 719                 if (!r)
 720                         continue;
 721                 if (!r->fetch)
 722                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 723                                                        r->fetch_refspec);
 724                 if (!r->push)
 725                         r->push = parse_push_refspec(r->push_refspec_nr,
 726                                                      r->push_refspec);
 727                 result = fn(r, priv);
 728         }
 729         return result;
 730 }
 731
 732 void ref_remove_duplicates(struct ref *ref_map)
 733 {
 734         struct string_list refs = STRING_LIST_INIT_NODUP;
 735         struct string_list_item *item = NULL;
 736         struct ref *prev = NULL, *next = NULL;
 737         for (; ref_map; prev = ref_map, ref_map = next) {
 738                 next = ref_map->next;
 739                 if (!ref_map->peer_ref)
 740                         continue;
 741
 742                 item = string_list_lookup(&refs, ref_map->peer_ref->name);
 743                 if (item) {
 744                         if (strcmp(((struct ref *)item->util)->name,
 745                                    ref_map->name))
 746                                 die("%s tracks both %s and %s",
 747                                     ref_map->peer_ref->name,
 748                                     ((struct ref *)item->util)->name,
 749                                     ref_map->name);
 750                         prev->next = ref_map->next;
 751                         free(ref_map->peer_ref);
 752                         free(ref_map);
 753                         ref_map = prev; /* skip this; we freed it */
 754                         continue;
 755                 }
 756
 757                 item = string_list_insert(&refs, ref_map->peer_ref->name);
 758                 item->util = ref_map;
 759         }
 760         string_list_clear(&refs, 0);
 761 }
 762
 763 int remote_has_url(struct remote *remote, const char *url)
 764 {
 765         int i;
 766         for (i = 0; i < remote->url_nr; i++) {
 767                 if (!strcmp(remote->url[i], url))
 768                         return 1;
 769         }
 770         return 0;
 771 }
 772
 773 static int match_name_with_pattern(const char *key, const char *name,
 774                                    const char *value, char **result)
 775 {
 776         const char *kstar = strchr(key, '*');
 777         size_t klen;
 778         size_t ksuffixlen;
 779         size_t namelen;
 780         int ret;
 781         if (!kstar)
 782                 die("Key '%s' of pattern had no '*'", key);
 783         klen = kstar - key;
 784         ksuffixlen = strlen(kstar + 1);
 785         namelen = strlen(name);
 786         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 787                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 788         if (ret && value) {
 789                 const char *vstar = strchr(value, '*');
 790                 size_t vlen;
 791                 size_t vsuffixlen;
 792                 if (!vstar)
 793                         die("Value '%s' of pattern has no '*'", value);
 794                 vlen = vstar - value;
 795                 vsuffixlen = strlen(vstar + 1);
 796                 *result = xmalloc(vlen + vsuffixlen +
 797                                   strlen(name) -
 798                                   klen - ksuffixlen + 1);
 799                 strncpy(*result, value, vlen);
 800                 strncpy(*result + vlen,
 801                         name + klen, namelen - klen - ksuffixlen);
 802                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
 803                        vstar + 1);
 804         }
 805         return ret;
 806 }
 807
 808 static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
 809 {
 810         int i;
 811         int find_src = !query->src;
 812
 813         if (find_src && !query->dst)
 814                 return error("query_refspecs: need either src or dst");
 815
 816         for (i = 0; i < ref_count; i++) {
 817                 struct refspec *refspec = &refs[i];
 818                 const char *key = find_src ? refspec->dst : refspec->src;
 819                 const char *value = find_src ? refspec->src : refspec->dst;
 820                 const char *needle = find_src ? query->dst : query->src;
 821                 char **result = find_src ? &query->src : &query->dst;
 822
 823                 if (!refspec->dst)
 824                         continue;
 825                 if (refspec->pattern) {
 826                         if (match_name_with_pattern(key, needle, value, result)) {
 827                                 query->force = refspec->force;
 828                                 return 0;
 829                         }
 830                 } else if (!strcmp(needle, key)) {
 831                         *result = xstrdup(value);
 832                         query->force = refspec->force;
 833                         return 0;
 834                 }
 835         }
 836         return -1;
 837 }
 838
 839 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 840                      const char *name)
 841 {
 842         struct refspec query;
 843
 844         memset(&query, 0, sizeof(struct refspec));
 845         query.src = (char *)name;
 846
 847         if (query_refspecs(refspecs, nr_refspec, &query))
 848                 return NULL;
 849
 850         return query.dst;
 851 }
 852
 853 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 854 {
 855         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
 856 }
 857
 858 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 859                 const char *name)
 860 {
 861         size_t len = strlen(name);
 862         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 863         memcpy(ref->name, prefix, prefixlen);
 864         memcpy(ref->name + prefixlen, name, len);
 865         return ref;
 866 }
 867
 868 struct ref *alloc_ref(const char *name)
 869 {
 870         return alloc_ref_with_prefix("", 0, name);
 871 }
 872
 873 struct ref *copy_ref(const struct ref *ref)
 874 {
 875         struct ref *cpy;
 876         size_t len;
 877         if (!ref)
 878                 return NULL;
 879         len = strlen(ref->name);
 880         cpy = xmalloc(sizeof(struct ref) + len + 1);
 881         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 882         cpy->next = NULL;
 883         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 884         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 885         cpy->peer_ref = copy_ref(ref->peer_ref);
 886         return cpy;
 887 }
 888
 889 struct ref *copy_ref_list(const struct ref *ref)
 890 {
 891         struct ref *ret = NULL;
 892         struct ref **tail = &ret;
 893         while (ref) {
 894                 *tail = copy_ref(ref);
 895                 ref = ref->next;
 896                 tail = &((*tail)->next);
 897         }
 898         return ret;
 899 }
 900
 901 static void free_ref(struct ref *ref)
 902 {
 903         if (!ref)
 904                 return;
 905         free_ref(ref->peer_ref);
 906         free(ref->remote_status);
 907         free(ref->symref);
 908         free(ref);
 909 }
 910
 911 void free_refs(struct ref *ref)
 912 {
 913         struct ref *next;
 914         while (ref) {
 915                 next = ref->next;
 916                 free_ref(ref);
 917                 ref = next;
 918         }
 919 }
 920
 921 int ref_compare_name(const void *va, const void *vb)
 922 {
 923         const struct ref *a = va, *b = vb;
 924         return strcmp(a->name, b->name);
 925 }
 926
 927 static void *ref_list_get_next(const void *a)
 928 {
 929         return ((const struct ref *)a)->next;
 930 }
 931
 932 static void ref_list_set_next(void *a, void *next)
 933 {
 934         ((struct ref *)a)->next = next;
 935 }
 936
 937 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
 938 {
 939         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
 940 }
 941
 942 static int count_refspec_match(const char *pattern,
 943                                struct ref *refs,
 944                                struct ref **matched_ref)
 945 {
 946         int patlen = strlen(pattern);
 947         struct ref *matched_weak = NULL;
 948         struct ref *matched = NULL;
 949         int weak_match = 0;
 950         int match = 0;
 951
 952         for (weak_match = match = 0; refs; refs = refs->next) {
 953                 char *name = refs->name;
 954                 int namelen = strlen(name);
 955
 956                 if (!refname_match(pattern, name, ref_rev_parse_rules))
 957                         continue;
 958
 959                 /* A match is "weak" if it is with refs outside
 960                  * heads or tags, and did not specify the pattern
 961                  * in full (e.g. "refs/remotes/origin/master") or at
 962                  * least from the toplevel (e.g. "remotes/origin/master");
 963                  * otherwise "git push $URL master" would result in
 964                  * ambiguity between remotes/origin/master and heads/master
 965                  * at the remote site.
 966                  */
 967                 if (namelen != patlen &&
 968                     patlen != namelen - 5 &&
 969                     prefixcmp(name, "refs/heads/") &&
 970                     prefixcmp(name, "refs/tags/")) {
 971                         /* We want to catch the case where only weak
 972                          * matches are found and there are multiple
 973                          * matches, and where more than one strong
 974                          * matches are found, as ambiguous.  One
 975                          * strong match with zero or more weak matches
 976                          * are acceptable as a unique match.
 977                          */
 978                         matched_weak = refs;
 979                         weak_match++;
 980                 }
 981                 else {
 982                         matched = refs;
 983                         match++;
 984                 }
 985         }
 986         if (!matched) {
 987                 *matched_ref = matched_weak;
 988                 return weak_match;
 989         }
 990         else {
 991                 *matched_ref = matched;
 992                 return match;
 993         }
 994 }
 995
 996 static void tail_link_ref(struct ref *ref, struct ref ***tail)
 997 {
 998         **tail = ref;
 999         while (ref->next)
1000                 ref = ref->next;
1001         *tail = &ref->next;
1002 }
1003
1004 static struct ref *alloc_delete_ref(void)
1005 {
1006         struct ref *ref = alloc_ref("(delete)");
1007         hashclr(ref->new_sha1);
1008         return ref;
1009 }
1010
1011 static struct ref *try_explicit_object_name(const char *name)
1012 {
1013         unsigned char sha1[20];
1014         struct ref *ref;
1015
1016         if (!*name)
1017                 return alloc_delete_ref();
1018         if (get_sha1(name, sha1))
1019                 return NULL;
1020         ref = alloc_ref(name);
1021         hashcpy(ref->new_sha1, sha1);
1022         return ref;
1023 }
1024
1025 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1026 {
1027         struct ref *ret = alloc_ref(name);
1028         tail_link_ref(ret, tail);
1029         return ret;
1030 }
1031
1032 static char *guess_ref(const char *name, struct ref *peer)
1033 {
1034         struct strbuf buf = STRBUF_INIT;
1035         unsigned char sha1[20];
1036
1037         const char *r = resolve_ref_unsafe(peer->name, sha1, 1, NULL);
1038         if (!r)
1039                 return NULL;
1040
1041         if (!prefixcmp(r, "refs/heads/"))
1042                 strbuf_addstr(&buf, "refs/heads/");
1043         else if (!prefixcmp(r, "refs/tags/"))
1044                 strbuf_addstr(&buf, "refs/tags/");
1045         else
1046                 return NULL;
1047
1048         strbuf_addstr(&buf, name);
1049         return strbuf_detach(&buf, NULL);
1050 }
1051
1052 static int match_explicit(struct ref *src, struct ref *dst,
1053                           struct ref ***dst_tail,
1054                           struct refspec *rs)
1055 {
1056         struct ref *matched_src, *matched_dst;
1057         int copy_src;
1058
1059         const char *dst_value = rs->dst;
1060         char *dst_guess;
1061
1062         if (rs->pattern || rs->matching)
1063                 return 0;
1064
1065         matched_src = matched_dst = NULL;
1066         switch (count_refspec_match(rs->src, src, &matched_src)) {
1067         case 1:
1068                 copy_src = 1;
1069                 break;
1070         case 0:
1071                 /* The source could be in the get_sha1() format
1072                  * not a reference name.  :refs/other is a
1073                  * way to delete 'other' ref at the remote end.
1074                  */
1075                 matched_src = try_explicit_object_name(rs->src);
1076                 if (!matched_src)
1077                         return error("src refspec %s does not match any.", rs->src);
1078                 copy_src = 0;
1079                 break;
1080         default:
1081                 return error("src refspec %s matches more than one.", rs->src);
1082         }
1083
1084         if (!dst_value) {
1085                 unsigned char sha1[20];
1086                 int flag;
1087
1088                 dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
1089                 if (!dst_value ||
1090                     ((flag & REF_ISSYMREF) &&
1091                      prefixcmp(dst_value, "refs/heads/")))
1092                         die("%s cannot be resolved to branch.",
1093                             matched_src->name);
1094         }
1095
1096         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1097         case 1:
1098                 break;
1099         case 0:
1100                 if (!memcmp(dst_value, "refs/", 5))
1101                         matched_dst = make_linked_ref(dst_value, dst_tail);
1102                 else if (is_null_sha1(matched_src->new_sha1))
1103                         error("unable to delete '%s': remote ref does not exist",
1104                               dst_value);
1105                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1106                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1107                 else
1108                         error("unable to push to unqualified destination: %s\n"
1109                               "The destination refspec neither matches an "
1110                               "existing ref on the remote nor\n"
1111                               "begins with refs/, and we are unable to "
1112                               "guess a prefix based on the source ref.",
1113                               dst_value);
1114                 break;
1115         default:
1116                 matched_dst = NULL;
1117                 error("dst refspec %s matches more than one.",
1118                       dst_value);
1119                 break;
1120         }
1121         if (!matched_dst)
1122                 return -1;
1123         if (matched_dst->peer_ref)
1124                 return error("dst ref %s receives from more than one src.",
1125                       matched_dst->name);
1126         else {
1127                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1128                 matched_dst->force = rs->force;
1129         }
1130         return 0;
1131 }
1132
1133 static int match_explicit_refs(struct ref *src, struct ref *dst,
1134                                struct ref ***dst_tail, struct refspec *rs,
1135                                int rs_nr)
1136 {
1137         int i, errs;
1138         for (i = errs = 0; i < rs_nr; i++)
1139                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1140         return errs;
1141 }
1142
1143 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1144                 int send_mirror, int direction, const struct refspec **ret_pat)
1145 {
1146         const struct refspec *pat;
1147         char *name;
1148         int i;
1149         int matching_refs = -1;
1150         for (i = 0; i < rs_nr; i++) {
1151                 if (rs[i].matching &&
1152                     (matching_refs == -1 || rs[i].force)) {
1153                         matching_refs = i;
1154                         continue;
1155                 }
1156
1157                 if (rs[i].pattern) {
1158                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1159                         int match;
1160                         if (direction == FROM_SRC)
1161                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1162                         else
1163                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1164                         if (match) {
1165                                 matching_refs = i;
1166                                 break;
1167                         }
1168                 }
1169         }
1170         if (matching_refs == -1)
1171                 return NULL;
1172
1173         pat = rs + matching_refs;
1174         if (pat->matching) {
1175                 /*
1176                  * "matching refs"; traditionally we pushed everything
1177                  * including refs outside refs/heads/ hierarchy, but
1178                  * that does not make much sense these days.
1179                  */
1180                 if (!send_mirror && prefixcmp(ref->name, "refs/heads/"))
1181                         return NULL;
1182                 name = xstrdup(ref->name);
1183         }
1184         if (ret_pat)
1185                 *ret_pat = pat;
1186         return name;
1187 }
1188
1189 static struct ref **tail_ref(struct ref **head)
1190 {
1191         struct ref **tail = head;
1192         while (*tail)
1193                 tail = &((*tail)->next);
1194         return tail;
1195 }
1196
1197 struct tips {
1198         struct commit **tip;
1199         int nr, alloc;
1200 };
1201
1202 static void add_to_tips(struct tips *tips, const unsigned char *sha1)
1203 {
1204         struct commit *commit;
1205
1206         if (is_null_sha1(sha1))
1207                 return;
1208         commit = lookup_commit_reference_gently(sha1, 1);
1209         if (!commit || (commit->object.flags & TMP_MARK))
1210                 return;
1211         commit->object.flags |= TMP_MARK;
1212         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1213         tips->tip[tips->nr++] = commit;
1214 }
1215
1216 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1217 {
1218         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1219         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1220         struct string_list_item *item;
1221         struct ref *ref;
1222         struct tips sent_tips;
1223
1224         /*
1225          * Collect everything we know they would have at the end of
1226          * this push, and collect all tags they have.
1227          */
1228         memset(&sent_tips, 0, sizeof(sent_tips));
1229         for (ref = *dst; ref; ref = ref->next) {
1230                 if (ref->peer_ref &&
1231                     !is_null_sha1(ref->peer_ref->new_sha1))
1232                         add_to_tips(&sent_tips, ref->peer_ref->new_sha1);
1233                 else
1234                         add_to_tips(&sent_tips, ref->old_sha1);
1235                 if (!prefixcmp(ref->name, "refs/tags/"))
1236                         string_list_append(&dst_tag, ref->name);
1237         }
1238         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1239
1240         sort_string_list(&dst_tag);
1241
1242         /* Collect tags they do not have. */
1243         for (ref = src; ref; ref = ref->next) {
1244                 if (prefixcmp(ref->name, "refs/tags/"))
1245                         continue; /* not a tag */
1246                 if (string_list_has_string(&dst_tag, ref->name))
1247                         continue; /* they already have it */
1248                 if (sha1_object_info(ref->new_sha1, NULL) != OBJ_TAG)
1249                         continue; /* be conservative */
1250                 item = string_list_append(&src_tag, ref->name);
1251                 item->util = ref;
1252         }
1253         string_list_clear(&dst_tag, 0);
1254
1255         /*
1256          * At this point, src_tag lists tags that are missing from
1257          * dst, and sent_tips lists the tips we are pushing or those
1258          * that we know they already have. An element in the src_tag
1259          * that is an ancestor of any of the sent_tips needs to be
1260          * sent to the other side.
1261          */
1262         if (sent_tips.nr) {
1263                 for_each_string_list_item(item, &src_tag) {
1264                         struct ref *ref = item->util;
1265                         struct ref *dst_ref;
1266                         struct commit *commit;
1267
1268                         if (is_null_sha1(ref->new_sha1))
1269                                 continue;
1270                         commit = lookup_commit_reference_gently(ref->new_sha1, 1);
1271                         if (!commit)
1272                                 /* not pushing a commit, which is not an error */
1273                                 continue;
1274
1275                         /*
1276                          * Is this tag, which they do not have, reachable from
1277                          * any of the commits we are sending?
1278                          */
1279                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1280                                 continue;
1281
1282                         /* Add it in */
1283                         dst_ref = make_linked_ref(ref->name, dst_tail);
1284                         hashcpy(dst_ref->new_sha1, ref->new_sha1);
1285                         dst_ref->peer_ref = copy_ref(ref);
1286                 }
1287         }
1288         string_list_clear(&src_tag, 0);
1289         free(sent_tips.tip);
1290 }
1291
1292 /*
1293  * Given the set of refs the local repository has, the set of refs the
1294  * remote repository has, and the refspec used for push, determine
1295  * what remote refs we will update and with what value by setting
1296  * peer_ref (which object is being pushed) and force (if the push is
1297  * forced) in elements of "dst". The function may add new elements to
1298  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1299  */
1300 int match_push_refs(struct ref *src, struct ref **dst,
1301                     int nr_refspec, const char **refspec, int flags)
1302 {
1303         struct refspec *rs;
1304         int send_all = flags & MATCH_REFS_ALL;
1305         int send_mirror = flags & MATCH_REFS_MIRROR;
1306         int send_prune = flags & MATCH_REFS_PRUNE;
1307         int errs;
1308         static const char *default_refspec[] = { ":", NULL };
1309         struct ref *ref, **dst_tail = tail_ref(dst);
1310
1311         if (!nr_refspec) {
1312                 nr_refspec = 1;
1313                 refspec = default_refspec;
1314         }
1315         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1316         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1317
1318         /* pick the remainder */
1319         for (ref = src; ref; ref = ref->next) {
1320                 struct ref *dst_peer;
1321                 const struct refspec *pat = NULL;
1322                 char *dst_name;
1323
1324                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1325                 if (!dst_name)
1326                         continue;
1327
1328                 dst_peer = find_ref_by_name(*dst, dst_name);
1329                 if (dst_peer) {
1330                         if (dst_peer->peer_ref)
1331                                 /* We're already sending something to this ref. */
1332                                 goto free_name;
1333                 } else {
1334                         if (pat->matching && !(send_all || send_mirror))
1335                                 /*
1336                                  * Remote doesn't have it, and we have no
1337                                  * explicit pattern, and we don't have
1338                                  * --all nor --mirror.
1339                                  */
1340                                 goto free_name;
1341
1342                         /* Create a new one and link it */
1343                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1344                         hashcpy(dst_peer->new_sha1, ref->new_sha1);
1345                 }
1346                 dst_peer->peer_ref = copy_ref(ref);
1347                 dst_peer->force = pat->force;
1348         free_name:
1349                 free(dst_name);
1350         }
1351
1352         if (flags & MATCH_REFS_FOLLOW_TAGS)
1353                 add_missing_tags(src, dst, &dst_tail);
1354
1355         if (send_prune) {
1356                 /* check for missing refs on the remote */
1357                 for (ref = *dst; ref; ref = ref->next) {
1358                         char *src_name;
1359
1360                         if (ref->peer_ref)
1361                                 /* We're already sending something to this ref. */
1362                                 continue;
1363
1364                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1365                         if (src_name) {
1366                                 if (!find_ref_by_name(src, src_name))
1367                                         ref->peer_ref = alloc_delete_ref();
1368                                 free(src_name);
1369                         }
1370                 }
1371         }
1372         if (errs)
1373                 return -1;
1374         return 0;
1375 }
1376
1377 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1378         int force_update)
1379 {
1380         struct ref *ref;
1381
1382         for (ref = remote_refs; ref; ref = ref->next) {
1383                 int force_ref_update = ref->force || force_update;
1384
1385                 if (ref->peer_ref)
1386                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1387                 else if (!send_mirror)
1388                         continue;
1389
1390                 ref->deletion = is_null_sha1(ref->new_sha1);
1391                 if (!ref->deletion &&
1392                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1393                         ref->status = REF_STATUS_UPTODATE;
1394                         continue;
1395                 }
1396
1397                 /*
1398                  * Decide whether an individual refspec A:B can be
1399                  * pushed.  The push will succeed if any of the
1400                  * following are true:
1401                  *
1402                  * (1) the remote reference B does not exist
1403                  *
1404                  * (2) the remote reference B is being removed (i.e.,
1405                  *     pushing :B where no source is specified)
1406                  *
1407                  * (3) the destination is not under refs/tags/, and
1408                  *     if the old and new value is a commit, the new
1409                  *     is a descendant of the old.
1410                  *
1411                  * (4) it is forced using the +A:B notation, or by
1412                  *     passing the --force argument
1413                  */
1414
1415                 if (!ref->deletion && !is_null_sha1(ref->old_sha1)) {
1416                         int why = 0; /* why would this push require --force? */
1417
1418                         if (!prefixcmp(ref->name, "refs/tags/"))
1419                                 why = REF_STATUS_REJECT_ALREADY_EXISTS;
1420                         else if (!has_sha1_file(ref->old_sha1))
1421                                 why = REF_STATUS_REJECT_FETCH_FIRST;
1422                         else if (!lookup_commit_reference_gently(ref->old_sha1, 1) ||
1423                                  !lookup_commit_reference_gently(ref->new_sha1, 1))
1424                                 why = REF_STATUS_REJECT_NEEDS_FORCE;
1425                         else if (!ref_newer(ref->new_sha1, ref->old_sha1))
1426                                 why = REF_STATUS_REJECT_NONFASTFORWARD;
1427
1428                         if (!force_ref_update)
1429                                 ref->status = why;
1430                         else if (why)
1431                                 ref->forced_update = 1;
1432                 }
1433         }
1434 }
1435
1436 struct branch *branch_get(const char *name)
1437 {
1438         struct branch *ret;
1439
1440         read_config();
1441         if (!name || !*name || !strcmp(name, "HEAD"))
1442                 ret = current_branch;
1443         else
1444                 ret = make_branch(name, 0);
1445         if (ret && ret->remote_name) {
1446                 ret->remote = remote_get(ret->remote_name);
1447                 if (ret->merge_nr) {
1448                         int i;
1449                         ret->merge = xcalloc(sizeof(*ret->merge),
1450                                              ret->merge_nr);
1451                         for (i = 0; i < ret->merge_nr; i++) {
1452                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1453                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1454                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1455                                     && !strcmp(ret->remote_name, "."))
1456                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1457                         }
1458                 }
1459         }
1460         return ret;
1461 }
1462
1463 int branch_has_merge_config(struct branch *branch)
1464 {
1465         return branch && !!branch->merge;
1466 }
1467
1468 int branch_merge_matches(struct branch *branch,
1469                                  int i,
1470                                  const char *refname)
1471 {
1472         if (!branch || i < 0 || i >= branch->merge_nr)
1473                 return 0;
1474         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1475 }
1476
1477 static int ignore_symref_update(const char *refname)
1478 {
1479         unsigned char sha1[20];
1480         int flag;
1481
1482         if (!resolve_ref_unsafe(refname, sha1, 0, &flag))
1483                 return 0; /* non-existing refs are OK */
1484         return (flag & REF_ISSYMREF);
1485 }
1486
1487 static struct ref *get_expanded_map(const struct ref *remote_refs,
1488                                     const struct refspec *refspec)
1489 {
1490         const struct ref *ref;
1491         struct ref *ret = NULL;
1492         struct ref **tail = &ret;
1493
1494         char *expn_name;
1495
1496         for (ref = remote_refs; ref; ref = ref->next) {
1497                 if (strchr(ref->name, '^'))
1498                         continue; /* a dereference item */
1499                 if (match_name_with_pattern(refspec->src, ref->name,
1500                                             refspec->dst, &expn_name) &&
1501                     !ignore_symref_update(expn_name)) {
1502                         struct ref *cpy = copy_ref(ref);
1503
1504                         cpy->peer_ref = alloc_ref(expn_name);
1505                         free(expn_name);
1506                         if (refspec->force)
1507                                 cpy->peer_ref->force = 1;
1508                         *tail = cpy;
1509                         tail = &cpy->next;
1510                 }
1511         }
1512
1513         return ret;
1514 }
1515
1516 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1517 {
1518         const struct ref *ref;
1519         for (ref = refs; ref; ref = ref->next) {
1520                 if (refname_match(name, ref->name, ref_fetch_rules))
1521                         return ref;
1522         }
1523         return NULL;
1524 }
1525
1526 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1527 {
1528         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1529
1530         if (!ref)
1531                 return NULL;
1532
1533         return copy_ref(ref);
1534 }
1535
1536 static struct ref *get_local_ref(const char *name)
1537 {
1538         if (!name || name[0] == '\0')
1539                 return NULL;
1540
1541         if (!prefixcmp(name, "refs/"))
1542                 return alloc_ref(name);
1543
1544         if (!prefixcmp(name, "heads/") ||
1545             !prefixcmp(name, "tags/") ||
1546             !prefixcmp(name, "remotes/"))
1547                 return alloc_ref_with_prefix("refs/", 5, name);
1548
1549         return alloc_ref_with_prefix("refs/heads/", 11, name);
1550 }
1551
1552 int get_fetch_map(const struct ref *remote_refs,
1553                   const struct refspec *refspec,
1554                   struct ref ***tail,
1555                   int missing_ok)
1556 {
1557         struct ref *ref_map, **rmp;
1558
1559         if (refspec->pattern) {
1560                 ref_map = get_expanded_map(remote_refs, refspec);
1561         } else {
1562                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1563
1564                 if (refspec->exact_sha1) {
1565                         ref_map = alloc_ref(name);
1566                         get_sha1_hex(name, ref_map->old_sha1);
1567                 } else {
1568                         ref_map = get_remote_ref(remote_refs, name);
1569                 }
1570                 if (!missing_ok && !ref_map)
1571                         die("Couldn't find remote ref %s", name);
1572                 if (ref_map) {
1573                         ref_map->peer_ref = get_local_ref(refspec->dst);
1574                         if (ref_map->peer_ref && refspec->force)
1575                                 ref_map->peer_ref->force = 1;
1576                 }
1577         }
1578
1579         for (rmp = &ref_map; *rmp; ) {
1580                 if ((*rmp)->peer_ref) {
1581                         if (prefixcmp((*rmp)->peer_ref->name, "refs/") ||
1582                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1583                                 struct ref *ignore = *rmp;
1584                                 error("* Ignoring funny ref '%s' locally",
1585                                       (*rmp)->peer_ref->name);
1586                                 *rmp = (*rmp)->next;
1587                                 free(ignore->peer_ref);
1588                                 free(ignore);
1589                                 continue;
1590                         }
1591                 }
1592                 rmp = &((*rmp)->next);
1593         }
1594
1595         if (ref_map)
1596                 tail_link_ref(ref_map, tail);
1597
1598         return 0;
1599 }
1600
1601 int resolve_remote_symref(struct ref *ref, struct ref *list)
1602 {
1603         if (!ref->symref)
1604                 return 0;
1605         for (; list; list = list->next)
1606                 if (!strcmp(ref->symref, list->name)) {
1607                         hashcpy(ref->old_sha1, list->old_sha1);
1608                         return 0;
1609                 }
1610         return 1;
1611 }
1612
1613 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1614 {
1615         while (list) {
1616                 struct commit_list *temp = list;
1617                 temp->item->object.flags &= ~mark;
1618                 list = temp->next;
1619                 free(temp);
1620         }
1621 }
1622
1623 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1624 {
1625         struct object *o;
1626         struct commit *old, *new;
1627         struct commit_list *list, *used;
1628         int found = 0;
1629
1630         /*
1631          * Both new and old must be commit-ish and new is descendant of
1632          * old.  Otherwise we require --force.
1633          */
1634         o = deref_tag(parse_object(old_sha1), NULL, 0);
1635         if (!o || o->type != OBJ_COMMIT)
1636                 return 0;
1637         old = (struct commit *) o;
1638
1639         o = deref_tag(parse_object(new_sha1), NULL, 0);
1640         if (!o || o->type != OBJ_COMMIT)
1641                 return 0;
1642         new = (struct commit *) o;
1643
1644         if (parse_commit(new) < 0)
1645                 return 0;
1646
1647         used = list = NULL;
1648         commit_list_insert(new, &list);
1649         while (list) {
1650                 new = pop_most_recent_commit(&list, TMP_MARK);
1651                 commit_list_insert(new, &used);
1652                 if (new == old) {
1653                         found = 1;
1654                         break;
1655                 }
1656         }
1657         unmark_and_free(list, TMP_MARK);
1658         unmark_and_free(used, TMP_MARK);
1659         return found;
1660 }
1661
1662 /*
1663  * Return true if there is anything to report, otherwise false.
1664  */
1665 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1666 {
1667         unsigned char sha1[20];
1668         struct commit *ours, *theirs;
1669         char symmetric[84];
1670         struct rev_info revs;
1671         const char *rev_argv[10], *base;
1672         int rev_argc;
1673
1674         /*
1675          * Nothing to report unless we are marked to build on top of
1676          * somebody else.
1677          */
1678         if (!branch ||
1679             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1680                 return 0;
1681
1682         /*
1683          * If what we used to build on no longer exists, there is
1684          * nothing to report.
1685          */
1686         base = branch->merge[0]->dst;
1687         if (read_ref(base, sha1))
1688                 return 0;
1689         theirs = lookup_commit_reference(sha1);
1690         if (!theirs)
1691                 return 0;
1692
1693         if (read_ref(branch->refname, sha1))
1694                 return 0;
1695         ours = lookup_commit_reference(sha1);
1696         if (!ours)
1697                 return 0;
1698
1699         /* are we the same? */
1700         if (theirs == ours)
1701                 return 0;
1702
1703         /* Run "rev-list --left-right ours...theirs" internally... */
1704         rev_argc = 0;
1705         rev_argv[rev_argc++] = NULL;
1706         rev_argv[rev_argc++] = "--left-right";
1707         rev_argv[rev_argc++] = symmetric;
1708         rev_argv[rev_argc++] = "--";
1709         rev_argv[rev_argc] = NULL;
1710
1711         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1712         strcpy(symmetric + 40, "...");
1713         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1714
1715         init_revisions(&revs, NULL);
1716         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1717         prepare_revision_walk(&revs);
1718
1719         /* ... and count the commits on each side. */
1720         *num_ours = 0;
1721         *num_theirs = 0;
1722         while (1) {
1723                 struct commit *c = get_revision(&revs);
1724                 if (!c)
1725                         break;
1726                 if (c->object.flags & SYMMETRIC_LEFT)
1727                         (*num_ours)++;
1728                 else
1729                         (*num_theirs)++;
1730         }
1731
1732         /* clear object flags smudged by the above traversal */
1733         clear_commit_marks(ours, ALL_REV_FLAGS);
1734         clear_commit_marks(theirs, ALL_REV_FLAGS);
1735         return 1;
1736 }
1737
1738 /*
1739  * Return true when there is anything to report, otherwise false.
1740  */
1741 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1742 {
1743         int num_ours, num_theirs;
1744         const char *base;
1745
1746         if (!stat_tracking_info(branch, &num_ours, &num_theirs))
1747                 return 0;
1748
1749         base = branch->merge[0]->dst;
1750         base = shorten_unambiguous_ref(base, 0);
1751         if (!num_theirs) {
1752                 strbuf_addf(sb,
1753                         Q_("Your branch is ahead of '%s' by %d commit.\n",
1754                            "Your branch is ahead of '%s' by %d commits.\n",
1755                            num_ours),
1756                         base, num_ours);
1757                 if (advice_status_hints)
1758                         strbuf_addf(sb,
1759                                 _("  (use \"git push\" to publish your local commits)\n"));
1760         } else if (!num_ours) {
1761                 strbuf_addf(sb,
1762                         Q_("Your branch is behind '%s' by %d commit, "
1763                                "and can be fast-forwarded.\n",
1764                            "Your branch is behind '%s' by %d commits, "
1765                                "and can be fast-forwarded.\n",
1766                            num_theirs),
1767                         base, num_theirs);
1768                 if (advice_status_hints)
1769                         strbuf_addf(sb,
1770                                 _("  (use \"git pull\" to update your local branch)\n"));
1771         } else {
1772                 strbuf_addf(sb,
1773                         Q_("Your branch and '%s' have diverged,\n"
1774                                "and have %d and %d different commit each, "
1775                                "respectively.\n",
1776                            "Your branch and '%s' have diverged,\n"
1777                                "and have %d and %d different commits each, "
1778                                "respectively.\n",
1779                            num_theirs),
1780                         base, num_ours, num_theirs);
1781                 if (advice_status_hints)
1782                         strbuf_addf(sb,
1783                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
1784         }
1785         return 1;
1786 }
1787
1788 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1789 {
1790         struct ref ***local_tail = cb_data;
1791         struct ref *ref;
1792         int len;
1793
1794         /* we already know it starts with refs/ to get here */
1795         if (check_refname_format(refname + 5, 0))
1796                 return 0;
1797
1798         len = strlen(refname) + 1;
1799         ref = xcalloc(1, sizeof(*ref) + len);
1800         hashcpy(ref->new_sha1, sha1);
1801         memcpy(ref->name, refname, len);
1802         **local_tail = ref;
1803         *local_tail = &ref->next;
1804         return 0;
1805 }
1806
1807 struct ref *get_local_heads(void)
1808 {
1809         struct ref *local_refs = NULL, **local_tail = &local_refs;
1810         for_each_ref(one_local_ref, &local_tail);
1811         return local_refs;
1812 }
1813
1814 struct ref *guess_remote_head(const struct ref *head,
1815                               const struct ref *refs,
1816                               int all)
1817 {
1818         const struct ref *r;
1819         struct ref *list = NULL;
1820         struct ref **tail = &list;
1821
1822         if (!head)
1823                 return NULL;
1824
1825         /*
1826          * Some transports support directly peeking at
1827          * where HEAD points; if that is the case, then
1828          * we don't have to guess.
1829          */
1830         if (head->symref)
1831                 return copy_ref(find_ref_by_name(refs, head->symref));
1832
1833         /* If refs/heads/master could be right, it is. */
1834         if (!all) {
1835                 r = find_ref_by_name(refs, "refs/heads/master");
1836                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1837                         return copy_ref(r);
1838         }
1839
1840         /* Look for another ref that points there */
1841         for (r = refs; r; r = r->next) {
1842                 if (r != head &&
1843                     !prefixcmp(r->name, "refs/heads/") &&
1844                     !hashcmp(r->old_sha1, head->old_sha1)) {
1845                         *tail = copy_ref(r);
1846                         tail = &((*tail)->next);
1847                         if (!all)
1848                                 break;
1849                 }
1850         }
1851
1852         return list;
1853 }
1854
1855 struct stale_heads_info {
1856         struct string_list *ref_names;
1857         struct ref **stale_refs_tail;
1858         struct refspec *refs;
1859         int ref_count;
1860 };
1861
1862 static int get_stale_heads_cb(const char *refname,
1863         const unsigned char *sha1, int flags, void *cb_data)
1864 {
1865         struct stale_heads_info *info = cb_data;
1866         struct refspec query;
1867         memset(&query, 0, sizeof(struct refspec));
1868         query.dst = (char *)refname;
1869
1870         if (query_refspecs(info->refs, info->ref_count, &query))
1871                 return 0; /* No matches */
1872
1873         /*
1874          * If we did find a suitable refspec and it's not a symref and
1875          * it's not in the list of refs that currently exist in that
1876          * remote we consider it to be stale.
1877          */
1878         if (!((flags & REF_ISSYMREF) ||
1879               string_list_has_string(info->ref_names, query.src))) {
1880                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
1881                 hashcpy(ref->new_sha1, sha1);
1882         }
1883
1884         free(query.src);
1885         return 0;
1886 }
1887
1888 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
1889 {
1890         struct ref *ref, *stale_refs = NULL;
1891         struct string_list ref_names = STRING_LIST_INIT_NODUP;
1892         struct stale_heads_info info;
1893         info.ref_names = &ref_names;
1894         info.stale_refs_tail = &stale_refs;
1895         info.refs = refs;
1896         info.ref_count = ref_count;
1897         for (ref = fetch_map; ref; ref = ref->next)
1898                 string_list_append(&ref_names, ref->name);
1899         sort_string_list(&ref_names);
1900         for_each_ref(get_stale_heads_cb, &info);
1901         string_list_clear(&ref_names, 0);
1902         return stale_refs;
1903 }