git.oblomov.eu Git - git/blob - 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 const char *pushremote_name;
  53 static int explicit_default_remote_name;
  54
  55 static struct rewrites rewrites;
  56 static struct rewrites rewrites_push;
  57
  58 #define BUF_SIZE (2048)
  59 static char buffer[BUF_SIZE];
  60
  61 static int valid_remote(const struct remote *remote)
  62 {
  63         return (!!remote->url) || (!!remote->foreign_vcs);
  64 }
  65
  66 static const char *alias_url(const char *url, struct rewrites *r)
  67 {
  68         int i, j;
  69         char *ret;
  70         struct counted_string *longest;
  71         int longest_i;
  72
  73         longest = NULL;
  74         longest_i = -1;
  75         for (i = 0; i < r->rewrite_nr; i++) {
  76                 if (!r->rewrite[i])
  77                         continue;
  78                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  79                         if (starts_with(url, r->rewrite[i]->instead_of[j].s) &&
  80                             (!longest ||
  81                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  82                                 longest = &(r->rewrite[i]->instead_of[j]);
  83                                 longest_i = i;
  84                         }
  85                 }
  86         }
  87         if (!longest)
  88                 return url;
  89
  90         ret = xmalloc(r->rewrite[longest_i]->baselen +
  91                      (strlen(url) - longest->len) + 1);
  92         strcpy(ret, r->rewrite[longest_i]->base);
  93         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
  94         return ret;
  95 }
  96
  97 static void add_push_refspec(struct remote *remote, const char *ref)
  98 {
  99         ALLOC_GROW(remote->push_refspec,
 100                    remote->push_refspec_nr + 1,
 101                    remote->push_refspec_alloc);
 102         remote->push_refspec[remote->push_refspec_nr++] = ref;
 103 }
 104
 105 static void add_fetch_refspec(struct remote *remote, const char *ref)
 106 {
 107         ALLOC_GROW(remote->fetch_refspec,
 108                    remote->fetch_refspec_nr + 1,
 109                    remote->fetch_refspec_alloc);
 110         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
 111 }
 112
 113 static void add_url(struct remote *remote, const char *url)
 114 {
 115         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
 116         remote->url[remote->url_nr++] = url;
 117 }
 118
 119 static void add_pushurl(struct remote *remote, const char *pushurl)
 120 {
 121         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
 122         remote->pushurl[remote->pushurl_nr++] = pushurl;
 123 }
 124
 125 static void add_pushurl_alias(struct remote *remote, const char *url)
 126 {
 127         const char *pushurl = alias_url(url, &rewrites_push);
 128         if (pushurl != url)
 129                 add_pushurl(remote, pushurl);
 130 }
 131
 132 static void add_url_alias(struct remote *remote, const char *url)
 133 {
 134         add_url(remote, alias_url(url, &rewrites));
 135         add_pushurl_alias(remote, url);
 136 }
 137
 138 static struct remote *make_remote(const char *name, int len)
 139 {
 140         struct remote *ret;
 141         int i;
 142
 143         for (i = 0; i < remotes_nr; i++) {
 144                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
 145                            !remotes[i]->name[len]) :
 146                     !strcmp(name, remotes[i]->name))
 147                         return remotes[i];
 148         }
 149
 150         ret = xcalloc(1, sizeof(struct remote));
 151         ret->prune = -1;  /* unspecified */
 152         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 153         remotes[remotes_nr++] = ret;
 154         if (len)
 155                 ret->name = xstrndup(name, len);
 156         else
 157                 ret->name = xstrdup(name);
 158         return ret;
 159 }
 160
 161 static void add_merge(struct branch *branch, const char *name)
 162 {
 163         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 164                    branch->merge_alloc);
 165         branch->merge_name[branch->merge_nr++] = name;
 166 }
 167
 168 static struct branch *make_branch(const char *name, int len)
 169 {
 170         struct branch *ret;
 171         int i;
 172         char *refname;
 173
 174         for (i = 0; i < branches_nr; i++) {
 175                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 176                            !branches[i]->name[len]) :
 177                     !strcmp(name, branches[i]->name))
 178                         return branches[i];
 179         }
 180
 181         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 182         ret = xcalloc(1, sizeof(struct branch));
 183         branches[branches_nr++] = ret;
 184         if (len)
 185                 ret->name = xstrndup(name, len);
 186         else
 187                 ret->name = xstrdup(name);
 188         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
 189         strcpy(refname, "refs/heads/");
 190         strcpy(refname + strlen("refs/heads/"), ret->name);
 191         ret->refname = refname;
 192
 193         return ret;
 194 }
 195
 196 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 197 {
 198         struct rewrite *ret;
 199         int i;
 200
 201         for (i = 0; i < r->rewrite_nr; i++) {
 202                 if (len
 203                     ? (len == r->rewrite[i]->baselen &&
 204                        !strncmp(base, r->rewrite[i]->base, len))
 205                     : !strcmp(base, r->rewrite[i]->base))
 206                         return r->rewrite[i];
 207         }
 208
 209         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 210         ret = xcalloc(1, sizeof(struct rewrite));
 211         r->rewrite[r->rewrite_nr++] = ret;
 212         if (len) {
 213                 ret->base = xstrndup(base, len);
 214                 ret->baselen = len;
 215         }
 216         else {
 217                 ret->base = xstrdup(base);
 218                 ret->baselen = strlen(base);
 219         }
 220         return ret;
 221 }
 222
 223 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 224 {
 225         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 226         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 227         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 228         rewrite->instead_of_nr++;
 229 }
 230
 231 static void read_remotes_file(struct remote *remote)
 232 {
 233         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 234
 235         if (!f)
 236                 return;
 237         remote->origin = REMOTE_REMOTES;
 238         while (fgets(buffer, BUF_SIZE, f)) {
 239                 int value_list;
 240                 char *s, *p;
 241
 242                 if (starts_with(buffer, "URL:")) {
 243                         value_list = 0;
 244                         s = buffer + 4;
 245                 } else if (starts_with(buffer, "Push:")) {
 246                         value_list = 1;
 247                         s = buffer + 5;
 248                 } else if (starts_with(buffer, "Pull:")) {
 249                         value_list = 2;
 250                         s = buffer + 5;
 251                 } else
 252                         continue;
 253
 254                 while (isspace(*s))
 255                         s++;
 256                 if (!*s)
 257                         continue;
 258
 259                 p = s + strlen(s);
 260                 while (isspace(p[-1]))
 261                         *--p = 0;
 262
 263                 switch (value_list) {
 264                 case 0:
 265                         add_url_alias(remote, xstrdup(s));
 266                         break;
 267                 case 1:
 268                         add_push_refspec(remote, xstrdup(s));
 269                         break;
 270                 case 2:
 271                         add_fetch_refspec(remote, xstrdup(s));
 272                         break;
 273                 }
 274         }
 275         fclose(f);
 276 }
 277
 278 static void read_branches_file(struct remote *remote)
 279 {
 280         char *frag;
 281         struct strbuf branch = STRBUF_INIT;
 282         int n = 1000;
 283         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
 284         char *s, *p;
 285         int len;
 286
 287         if (!f)
 288                 return;
 289         s = fgets(buffer, BUF_SIZE, f);
 290         fclose(f);
 291         if (!s)
 292                 return;
 293         while (isspace(*s))
 294                 s++;
 295         if (!*s)
 296                 return;
 297         remote->origin = REMOTE_BRANCHES;
 298         p = s + strlen(s);
 299         while (isspace(p[-1]))
 300                 *--p = 0;
 301         len = p - s;
 302         p = xmalloc(len + 1);
 303         strcpy(p, s);
 304
 305         /*
 306          * The branches file would have URL and optionally
 307          * #branch specified.  The "master" (or specified) branch is
 308          * fetched and stored in the local branch of the same name.
 309          */
 310         frag = strchr(p, '#');
 311         if (frag) {
 312                 *(frag++) = '\0';
 313                 strbuf_addf(&branch, "refs/heads/%s", frag);
 314         } else
 315                 strbuf_addstr(&branch, "refs/heads/master");
 316
 317         strbuf_addf(&branch, ":refs/heads/%s", remote->name);
 318         add_url_alias(remote, p);
 319         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
 320         /*
 321          * Cogito compatible push: push current HEAD to remote #branch
 322          * (master if missing)
 323          */
 324         strbuf_init(&branch, 0);
 325         strbuf_addstr(&branch, "HEAD");
 326         if (frag)
 327                 strbuf_addf(&branch, ":refs/heads/%s", frag);
 328         else
 329                 strbuf_addstr(&branch, ":refs/heads/master");
 330         add_push_refspec(remote, strbuf_detach(&branch, NULL));
 331         remote->fetch_tags = 1; /* always auto-follow */
 332 }
 333
 334 static int handle_config(const char *key, const char *value, void *cb)
 335 {
 336         const char *name;
 337         const char *subkey;
 338         struct remote *remote;
 339         struct branch *branch;
 340         if (starts_with(key, "branch.")) {
 341                 name = key + 7;
 342                 subkey = strrchr(name, '.');
 343                 if (!subkey)
 344                         return 0;
 345                 branch = make_branch(name, subkey - name);
 346                 if (!strcmp(subkey, ".remote")) {
 347                         if (git_config_string(&branch->remote_name, key, value))
 348                                 return -1;
 349                         if (branch == current_branch) {
 350                                 default_remote_name = branch->remote_name;
 351                                 explicit_default_remote_name = 1;
 352                         }
 353                 } else if (!strcmp(subkey, ".pushremote")) {
 354                         if (branch == current_branch)
 355                                 if (git_config_string(&pushremote_name, key, value))
 356                                         return -1;
 357                 } else if (!strcmp(subkey, ".merge")) {
 358                         if (!value)
 359                                 return config_error_nonbool(key);
 360                         add_merge(branch, xstrdup(value));
 361                 }
 362                 return 0;
 363         }
 364         if (starts_with(key, "url.")) {
 365                 struct rewrite *rewrite;
 366                 name = key + 4;
 367                 subkey = strrchr(name, '.');
 368                 if (!subkey)
 369                         return 0;
 370                 if (!strcmp(subkey, ".insteadof")) {
 371                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 372                         if (!value)
 373                                 return config_error_nonbool(key);
 374                         add_instead_of(rewrite, xstrdup(value));
 375                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 376                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 377                         if (!value)
 378                                 return config_error_nonbool(key);
 379                         add_instead_of(rewrite, xstrdup(value));
 380                 }
 381         }
 382
 383         if (!starts_with(key,  "remote."))
 384                 return 0;
 385         name = key + 7;
 386
 387         /* Handle remote.* variables */
 388         if (!strcmp(name, "pushdefault"))
 389                 return git_config_string(&pushremote_name, key, value);
 390
 391         /* Handle remote.<name>.* variables */
 392         if (*name == '/') {
 393                 warning("Config remote shorthand cannot begin with '/': %s",
 394                         name);
 395                 return 0;
 396         }
 397         subkey = strrchr(name, '.');
 398         if (!subkey)
 399                 return 0;
 400         remote = make_remote(name, subkey - name);
 401         remote->origin = REMOTE_CONFIG;
 402         if (!strcmp(subkey, ".mirror"))
 403                 remote->mirror = git_config_bool(key, value);
 404         else if (!strcmp(subkey, ".skipdefaultupdate"))
 405                 remote->skip_default_update = git_config_bool(key, value);
 406         else if (!strcmp(subkey, ".skipfetchall"))
 407                 remote->skip_default_update = git_config_bool(key, value);
 408         else if (!strcmp(subkey, ".prune"))
 409                 remote->prune = 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 = "origin";
 487         current_branch = NULL;
 488         head_ref = resolve_ref_unsafe("HEAD", sha1, 0, &flag);
 489         if (head_ref && (flag & REF_ISSYMREF) &&
 490             starts_with(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 static struct remote *remote_get_1(const char *name, const char *pushremote_name)
 674 {
 675         struct remote *ret;
 676         int name_given = 0;
 677
 678         if (name)
 679                 name_given = 1;
 680         else {
 681                 if (pushremote_name) {
 682                         name = pushremote_name;
 683                         name_given = 1;
 684                 } else {
 685                         name = default_remote_name;
 686                         name_given = explicit_default_remote_name;
 687                 }
 688         }
 689
 690         ret = make_remote(name, 0);
 691         if (valid_remote_nick(name)) {
 692                 if (!valid_remote(ret))
 693                         read_remotes_file(ret);
 694                 if (!valid_remote(ret))
 695                         read_branches_file(ret);
 696         }
 697         if (name_given && !valid_remote(ret))
 698                 add_url_alias(ret, name);
 699         if (!valid_remote(ret))
 700                 return NULL;
 701         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 702         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 703         return ret;
 704 }
 705
 706 struct remote *remote_get(const char *name)
 707 {
 708         read_config();
 709         return remote_get_1(name, NULL);
 710 }
 711
 712 struct remote *pushremote_get(const char *name)
 713 {
 714         read_config();
 715         return remote_get_1(name, pushremote_name);
 716 }
 717
 718 int remote_is_configured(const char *name)
 719 {
 720         int i;
 721         read_config();
 722
 723         for (i = 0; i < remotes_nr; i++)
 724                 if (!strcmp(name, remotes[i]->name))
 725                         return 1;
 726         return 0;
 727 }
 728
 729 int for_each_remote(each_remote_fn fn, void *priv)
 730 {
 731         int i, result = 0;
 732         read_config();
 733         for (i = 0; i < remotes_nr && !result; i++) {
 734                 struct remote *r = remotes[i];
 735                 if (!r)
 736                         continue;
 737                 if (!r->fetch)
 738                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 739                                                        r->fetch_refspec);
 740                 if (!r->push)
 741                         r->push = parse_push_refspec(r->push_refspec_nr,
 742                                                      r->push_refspec);
 743                 result = fn(r, priv);
 744         }
 745         return result;
 746 }
 747
 748 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
 749 {
 750         if (strcmp(ref1->name, ref2->name)) {
 751                 if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 752                     ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
 753                         die(_("Cannot fetch both %s and %s to %s"),
 754                             ref1->name, ref2->name, ref2->peer_ref->name);
 755                 } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 756                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 757                         warning(_("%s usually tracks %s, not %s"),
 758                                 ref2->peer_ref->name, ref2->name, ref1->name);
 759                 } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
 760                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 761                         die(_("%s tracks both %s and %s"),
 762                             ref2->peer_ref->name, ref1->name, ref2->name);
 763                 } else {
 764                         /*
 765                          * This last possibility doesn't occur because
 766                          * FETCH_HEAD_IGNORE entries always appear at
 767                          * the end of the list.
 768                          */
 769                         die(_("Internal error"));
 770                 }
 771         }
 772         free(ref2->peer_ref);
 773         free(ref2);
 774 }
 775
 776 struct ref *ref_remove_duplicates(struct ref *ref_map)
 777 {
 778         struct string_list refs = STRING_LIST_INIT_NODUP;
 779         struct ref *retval = NULL;
 780         struct ref **p = &retval;
 781
 782         while (ref_map) {
 783                 struct ref *ref = ref_map;
 784
 785                 ref_map = ref_map->next;
 786                 ref->next = NULL;
 787
 788                 if (!ref->peer_ref) {
 789                         *p = ref;
 790                         p = &ref->next;
 791                 } else {
 792                         struct string_list_item *item =
 793                                 string_list_insert(&refs, ref->peer_ref->name);
 794
 795                         if (item->util) {
 796                                 /* Entry already existed */
 797                                 handle_duplicate((struct ref *)item->util, ref);
 798                         } else {
 799                                 *p = ref;
 800                                 p = &ref->next;
 801                                 item->util = ref;
 802                         }
 803                 }
 804         }
 805
 806         string_list_clear(&refs, 0);
 807         return retval;
 808 }
 809
 810 int remote_has_url(struct remote *remote, const char *url)
 811 {
 812         int i;
 813         for (i = 0; i < remote->url_nr; i++) {
 814                 if (!strcmp(remote->url[i], url))
 815                         return 1;
 816         }
 817         return 0;
 818 }
 819
 820 static int match_name_with_pattern(const char *key, const char *name,
 821                                    const char *value, char **result)
 822 {
 823         const char *kstar = strchr(key, '*');
 824         size_t klen;
 825         size_t ksuffixlen;
 826         size_t namelen;
 827         int ret;
 828         if (!kstar)
 829                 die("Key '%s' of pattern had no '*'", key);
 830         klen = kstar - key;
 831         ksuffixlen = strlen(kstar + 1);
 832         namelen = strlen(name);
 833         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 834                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 835         if (ret && value) {
 836                 const char *vstar = strchr(value, '*');
 837                 size_t vlen;
 838                 size_t vsuffixlen;
 839                 if (!vstar)
 840                         die("Value '%s' of pattern has no '*'", value);
 841                 vlen = vstar - value;
 842                 vsuffixlen = strlen(vstar + 1);
 843                 *result = xmalloc(vlen + vsuffixlen +
 844                                   strlen(name) -
 845                                   klen - ksuffixlen + 1);
 846                 strncpy(*result, value, vlen);
 847                 strncpy(*result + vlen,
 848                         name + klen, namelen - klen - ksuffixlen);
 849                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
 850                        vstar + 1);
 851         }
 852         return ret;
 853 }
 854
 855 int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
 856 {
 857         int i;
 858         int find_src = !query->src;
 859         const char *needle = find_src ? query->dst : query->src;
 860         char **result = find_src ? &query->src : &query->dst;
 861
 862         if (find_src && !query->dst)
 863                 return error("query_refspecs: need either src or dst");
 864
 865         for (i = 0; i < ref_count; i++) {
 866                 struct refspec *refspec = &refs[i];
 867                 const char *key = find_src ? refspec->dst : refspec->src;
 868                 const char *value = find_src ? refspec->src : refspec->dst;
 869
 870                 if (!refspec->dst)
 871                         continue;
 872                 if (refspec->pattern) {
 873                         if (match_name_with_pattern(key, needle, value, result)) {
 874                                 query->force = refspec->force;
 875                                 return 0;
 876                         }
 877                 } else if (!strcmp(needle, key)) {
 878                         *result = xstrdup(value);
 879                         query->force = refspec->force;
 880                         return 0;
 881                 }
 882         }
 883         return -1;
 884 }
 885
 886 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 887                      const char *name)
 888 {
 889         struct refspec query;
 890
 891         memset(&query, 0, sizeof(struct refspec));
 892         query.src = (char *)name;
 893
 894         if (query_refspecs(refspecs, nr_refspec, &query))
 895                 return NULL;
 896
 897         return query.dst;
 898 }
 899
 900 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 901 {
 902         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
 903 }
 904
 905 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 906                 const char *name)
 907 {
 908         size_t len = strlen(name);
 909         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 910         memcpy(ref->name, prefix, prefixlen);
 911         memcpy(ref->name + prefixlen, name, len);
 912         return ref;
 913 }
 914
 915 struct ref *alloc_ref(const char *name)
 916 {
 917         return alloc_ref_with_prefix("", 0, name);
 918 }
 919
 920 struct ref *copy_ref(const struct ref *ref)
 921 {
 922         struct ref *cpy;
 923         size_t len;
 924         if (!ref)
 925                 return NULL;
 926         len = strlen(ref->name);
 927         cpy = xmalloc(sizeof(struct ref) + len + 1);
 928         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 929         cpy->next = NULL;
 930         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 931         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 932         cpy->peer_ref = copy_ref(ref->peer_ref);
 933         return cpy;
 934 }
 935
 936 struct ref *copy_ref_list(const struct ref *ref)
 937 {
 938         struct ref *ret = NULL;
 939         struct ref **tail = &ret;
 940         while (ref) {
 941                 *tail = copy_ref(ref);
 942                 ref = ref->next;
 943                 tail = &((*tail)->next);
 944         }
 945         return ret;
 946 }
 947
 948 static void free_ref(struct ref *ref)
 949 {
 950         if (!ref)
 951                 return;
 952         free_ref(ref->peer_ref);
 953         free(ref->remote_status);
 954         free(ref->symref);
 955         free(ref);
 956 }
 957
 958 void free_refs(struct ref *ref)
 959 {
 960         struct ref *next;
 961         while (ref) {
 962                 next = ref->next;
 963                 free_ref(ref);
 964                 ref = next;
 965         }
 966 }
 967
 968 int ref_compare_name(const void *va, const void *vb)
 969 {
 970         const struct ref *a = va, *b = vb;
 971         return strcmp(a->name, b->name);
 972 }
 973
 974 static void *ref_list_get_next(const void *a)
 975 {
 976         return ((const struct ref *)a)->next;
 977 }
 978
 979 static void ref_list_set_next(void *a, void *next)
 980 {
 981         ((struct ref *)a)->next = next;
 982 }
 983
 984 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
 985 {
 986         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
 987 }
 988
 989 int count_refspec_match(const char *pattern,
 990                         struct ref *refs,
 991                         struct ref **matched_ref)
 992 {
 993         int patlen = strlen(pattern);
 994         struct ref *matched_weak = NULL;
 995         struct ref *matched = NULL;
 996         int weak_match = 0;
 997         int match = 0;
 998
 999         for (weak_match = match = 0; refs; refs = refs->next) {
1000                 char *name = refs->name;
1001                 int namelen = strlen(name);
1002
1003                 if (!refname_match(pattern, name, ref_rev_parse_rules))
1004                         continue;
1005
1006                 /* A match is "weak" if it is with refs outside
1007                  * heads or tags, and did not specify the pattern
1008                  * in full (e.g. "refs/remotes/origin/master") or at
1009                  * least from the toplevel (e.g. "remotes/origin/master");
1010                  * otherwise "git push $URL master" would result in
1011                  * ambiguity between remotes/origin/master and heads/master
1012                  * at the remote site.
1013                  */
1014                 if (namelen != patlen &&
1015                     patlen != namelen - 5 &&
1016                     !starts_with(name, "refs/heads/") &&
1017                     !starts_with(name, "refs/tags/")) {
1018                         /* We want to catch the case where only weak
1019                          * matches are found and there are multiple
1020                          * matches, and where more than one strong
1021                          * matches are found, as ambiguous.  One
1022                          * strong match with zero or more weak matches
1023                          * are acceptable as a unique match.
1024                          */
1025                         matched_weak = refs;
1026                         weak_match++;
1027                 }
1028                 else {
1029                         matched = refs;
1030                         match++;
1031                 }
1032         }
1033         if (!matched) {
1034                 *matched_ref = matched_weak;
1035                 return weak_match;
1036         }
1037         else {
1038                 *matched_ref = matched;
1039                 return match;
1040         }
1041 }
1042
1043 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1044 {
1045         **tail = ref;
1046         while (ref->next)
1047                 ref = ref->next;
1048         *tail = &ref->next;
1049 }
1050
1051 static struct ref *alloc_delete_ref(void)
1052 {
1053         struct ref *ref = alloc_ref("(delete)");
1054         hashclr(ref->new_sha1);
1055         return ref;
1056 }
1057
1058 static struct ref *try_explicit_object_name(const char *name)
1059 {
1060         unsigned char sha1[20];
1061         struct ref *ref;
1062
1063         if (!*name)
1064                 return alloc_delete_ref();
1065         if (get_sha1(name, sha1))
1066                 return NULL;
1067         ref = alloc_ref(name);
1068         hashcpy(ref->new_sha1, sha1);
1069         return ref;
1070 }
1071
1072 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1073 {
1074         struct ref *ret = alloc_ref(name);
1075         tail_link_ref(ret, tail);
1076         return ret;
1077 }
1078
1079 static char *guess_ref(const char *name, struct ref *peer)
1080 {
1081         struct strbuf buf = STRBUF_INIT;
1082         unsigned char sha1[20];
1083
1084         const char *r = resolve_ref_unsafe(peer->name, sha1, 1, NULL);
1085         if (!r)
1086                 return NULL;
1087
1088         if (starts_with(r, "refs/heads/"))
1089                 strbuf_addstr(&buf, "refs/heads/");
1090         else if (starts_with(r, "refs/tags/"))
1091                 strbuf_addstr(&buf, "refs/tags/");
1092         else
1093                 return NULL;
1094
1095         strbuf_addstr(&buf, name);
1096         return strbuf_detach(&buf, NULL);
1097 }
1098
1099 static int match_explicit(struct ref *src, struct ref *dst,
1100                           struct ref ***dst_tail,
1101                           struct refspec *rs)
1102 {
1103         struct ref *matched_src, *matched_dst;
1104         int copy_src;
1105
1106         const char *dst_value = rs->dst;
1107         char *dst_guess;
1108
1109         if (rs->pattern || rs->matching)
1110                 return 0;
1111
1112         matched_src = matched_dst = NULL;
1113         switch (count_refspec_match(rs->src, src, &matched_src)) {
1114         case 1:
1115                 copy_src = 1;
1116                 break;
1117         case 0:
1118                 /* The source could be in the get_sha1() format
1119                  * not a reference name.  :refs/other is a
1120                  * way to delete 'other' ref at the remote end.
1121                  */
1122                 matched_src = try_explicit_object_name(rs->src);
1123                 if (!matched_src)
1124                         return error("src refspec %s does not match any.", rs->src);
1125                 copy_src = 0;
1126                 break;
1127         default:
1128                 return error("src refspec %s matches more than one.", rs->src);
1129         }
1130
1131         if (!dst_value) {
1132                 unsigned char sha1[20];
1133                 int flag;
1134
1135                 dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
1136                 if (!dst_value ||
1137                     ((flag & REF_ISSYMREF) &&
1138                      !starts_with(dst_value, "refs/heads/")))
1139                         die("%s cannot be resolved to branch.",
1140                             matched_src->name);
1141         }
1142
1143         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1144         case 1:
1145                 break;
1146         case 0:
1147                 if (!memcmp(dst_value, "refs/", 5))
1148                         matched_dst = make_linked_ref(dst_value, dst_tail);
1149                 else if (is_null_sha1(matched_src->new_sha1))
1150                         error("unable to delete '%s': remote ref does not exist",
1151                               dst_value);
1152                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1153                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1154                 else
1155                         error("unable to push to unqualified destination: %s\n"
1156                               "The destination refspec neither matches an "
1157                               "existing ref on the remote nor\n"
1158                               "begins with refs/, and we are unable to "
1159                               "guess a prefix based on the source ref.",
1160                               dst_value);
1161                 break;
1162         default:
1163                 matched_dst = NULL;
1164                 error("dst refspec %s matches more than one.",
1165                       dst_value);
1166                 break;
1167         }
1168         if (!matched_dst)
1169                 return -1;
1170         if (matched_dst->peer_ref)
1171                 return error("dst ref %s receives from more than one src.",
1172                       matched_dst->name);
1173         else {
1174                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1175                 matched_dst->force = rs->force;
1176         }
1177         return 0;
1178 }
1179
1180 static int match_explicit_refs(struct ref *src, struct ref *dst,
1181                                struct ref ***dst_tail, struct refspec *rs,
1182                                int rs_nr)
1183 {
1184         int i, errs;
1185         for (i = errs = 0; i < rs_nr; i++)
1186                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1187         return errs;
1188 }
1189
1190 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1191                 int send_mirror, int direction, const struct refspec **ret_pat)
1192 {
1193         const struct refspec *pat;
1194         char *name;
1195         int i;
1196         int matching_refs = -1;
1197         for (i = 0; i < rs_nr; i++) {
1198                 if (rs[i].matching &&
1199                     (matching_refs == -1 || rs[i].force)) {
1200                         matching_refs = i;
1201                         continue;
1202                 }
1203
1204                 if (rs[i].pattern) {
1205                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1206                         int match;
1207                         if (direction == FROM_SRC)
1208                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1209                         else
1210                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1211                         if (match) {
1212                                 matching_refs = i;
1213                                 break;
1214                         }
1215                 }
1216         }
1217         if (matching_refs == -1)
1218                 return NULL;
1219
1220         pat = rs + matching_refs;
1221         if (pat->matching) {
1222                 /*
1223                  * "matching refs"; traditionally we pushed everything
1224                  * including refs outside refs/heads/ hierarchy, but
1225                  * that does not make much sense these days.
1226                  */
1227                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1228                         return NULL;
1229                 name = xstrdup(ref->name);
1230         }
1231         if (ret_pat)
1232                 *ret_pat = pat;
1233         return name;
1234 }
1235
1236 static struct ref **tail_ref(struct ref **head)
1237 {
1238         struct ref **tail = head;
1239         while (*tail)
1240                 tail = &((*tail)->next);
1241         return tail;
1242 }
1243
1244 struct tips {
1245         struct commit **tip;
1246         int nr, alloc;
1247 };
1248
1249 static void add_to_tips(struct tips *tips, const unsigned char *sha1)
1250 {
1251         struct commit *commit;
1252
1253         if (is_null_sha1(sha1))
1254                 return;
1255         commit = lookup_commit_reference_gently(sha1, 1);
1256         if (!commit || (commit->object.flags & TMP_MARK))
1257                 return;
1258         commit->object.flags |= TMP_MARK;
1259         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1260         tips->tip[tips->nr++] = commit;
1261 }
1262
1263 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1264 {
1265         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1266         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1267         struct string_list_item *item;
1268         struct ref *ref;
1269         struct tips sent_tips;
1270
1271         /*
1272          * Collect everything we know they would have at the end of
1273          * this push, and collect all tags they have.
1274          */
1275         memset(&sent_tips, 0, sizeof(sent_tips));
1276         for (ref = *dst; ref; ref = ref->next) {
1277                 if (ref->peer_ref &&
1278                     !is_null_sha1(ref->peer_ref->new_sha1))
1279                         add_to_tips(&sent_tips, ref->peer_ref->new_sha1);
1280                 else
1281                         add_to_tips(&sent_tips, ref->old_sha1);
1282                 if (starts_with(ref->name, "refs/tags/"))
1283                         string_list_append(&dst_tag, ref->name);
1284         }
1285         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1286
1287         sort_string_list(&dst_tag);
1288
1289         /* Collect tags they do not have. */
1290         for (ref = src; ref; ref = ref->next) {
1291                 if (!starts_with(ref->name, "refs/tags/"))
1292                         continue; /* not a tag */
1293                 if (string_list_has_string(&dst_tag, ref->name))
1294                         continue; /* they already have it */
1295                 if (sha1_object_info(ref->new_sha1, NULL) != OBJ_TAG)
1296                         continue; /* be conservative */
1297                 item = string_list_append(&src_tag, ref->name);
1298                 item->util = ref;
1299         }
1300         string_list_clear(&dst_tag, 0);
1301
1302         /*
1303          * At this point, src_tag lists tags that are missing from
1304          * dst, and sent_tips lists the tips we are pushing or those
1305          * that we know they already have. An element in the src_tag
1306          * that is an ancestor of any of the sent_tips needs to be
1307          * sent to the other side.
1308          */
1309         if (sent_tips.nr) {
1310                 for_each_string_list_item(item, &src_tag) {
1311                         struct ref *ref = item->util;
1312                         struct ref *dst_ref;
1313                         struct commit *commit;
1314
1315                         if (is_null_sha1(ref->new_sha1))
1316                                 continue;
1317                         commit = lookup_commit_reference_gently(ref->new_sha1, 1);
1318                         if (!commit)
1319                                 /* not pushing a commit, which is not an error */
1320                                 continue;
1321
1322                         /*
1323                          * Is this tag, which they do not have, reachable from
1324                          * any of the commits we are sending?
1325                          */
1326                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1327                                 continue;
1328
1329                         /* Add it in */
1330                         dst_ref = make_linked_ref(ref->name, dst_tail);
1331                         hashcpy(dst_ref->new_sha1, ref->new_sha1);
1332                         dst_ref->peer_ref = copy_ref(ref);
1333                 }
1334         }
1335         string_list_clear(&src_tag, 0);
1336         free(sent_tips.tip);
1337 }
1338
1339 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1340 {
1341         for ( ; list; list = list->next)
1342                 if (!strcmp(list->name, name))
1343                         return (struct ref *)list;
1344         return NULL;
1345 }
1346
1347 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1348 {
1349         for ( ; ref; ref = ref->next)
1350                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1351
1352         sort_string_list(ref_index);
1353 }
1354
1355 /*
1356  * Given the set of refs the local repository has, the set of refs the
1357  * remote repository has, and the refspec used for push, determine
1358  * what remote refs we will update and with what value by setting
1359  * peer_ref (which object is being pushed) and force (if the push is
1360  * forced) in elements of "dst". The function may add new elements to
1361  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1362  */
1363 int match_push_refs(struct ref *src, struct ref **dst,
1364                     int nr_refspec, const char **refspec, int flags)
1365 {
1366         struct refspec *rs;
1367         int send_all = flags & MATCH_REFS_ALL;
1368         int send_mirror = flags & MATCH_REFS_MIRROR;
1369         int send_prune = flags & MATCH_REFS_PRUNE;
1370         int errs;
1371         static const char *default_refspec[] = { ":", NULL };
1372         struct ref *ref, **dst_tail = tail_ref(dst);
1373         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1374
1375         if (!nr_refspec) {
1376                 nr_refspec = 1;
1377                 refspec = default_refspec;
1378         }
1379         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1380         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1381
1382         /* pick the remainder */
1383         for (ref = src; ref; ref = ref->next) {
1384                 struct string_list_item *dst_item;
1385                 struct ref *dst_peer;
1386                 const struct refspec *pat = NULL;
1387                 char *dst_name;
1388
1389                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1390                 if (!dst_name)
1391                         continue;
1392
1393                 if (!dst_ref_index.nr)
1394                         prepare_ref_index(&dst_ref_index, *dst);
1395
1396                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1397                 dst_peer = dst_item ? dst_item->util : NULL;
1398                 if (dst_peer) {
1399                         if (dst_peer->peer_ref)
1400                                 /* We're already sending something to this ref. */
1401                                 goto free_name;
1402                 } else {
1403                         if (pat->matching && !(send_all || send_mirror))
1404                                 /*
1405                                  * Remote doesn't have it, and we have no
1406                                  * explicit pattern, and we don't have
1407                                  * --all nor --mirror.
1408                                  */
1409                                 goto free_name;
1410
1411                         /* Create a new one and link it */
1412                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1413                         hashcpy(dst_peer->new_sha1, ref->new_sha1);
1414                         string_list_insert(&dst_ref_index,
1415                                 dst_peer->name)->util = dst_peer;
1416                 }
1417                 dst_peer->peer_ref = copy_ref(ref);
1418                 dst_peer->force = pat->force;
1419         free_name:
1420                 free(dst_name);
1421         }
1422
1423         string_list_clear(&dst_ref_index, 0);
1424
1425         if (flags & MATCH_REFS_FOLLOW_TAGS)
1426                 add_missing_tags(src, dst, &dst_tail);
1427
1428         if (send_prune) {
1429                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1430                 /* check for missing refs on the remote */
1431                 for (ref = *dst; ref; ref = ref->next) {
1432                         char *src_name;
1433
1434                         if (ref->peer_ref)
1435                                 /* We're already sending something to this ref. */
1436                                 continue;
1437
1438                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1439                         if (src_name) {
1440                                 if (!src_ref_index.nr)
1441                                         prepare_ref_index(&src_ref_index, src);
1442                                 if (!string_list_has_string(&src_ref_index,
1443                                             src_name))
1444                                         ref->peer_ref = alloc_delete_ref();
1445                                 free(src_name);
1446                         }
1447                 }
1448                 string_list_clear(&src_ref_index, 0);
1449         }
1450         if (errs)
1451                 return -1;
1452         return 0;
1453 }
1454
1455 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1456                              int force_update)
1457 {
1458         struct ref *ref;
1459
1460         for (ref = remote_refs; ref; ref = ref->next) {
1461                 int force_ref_update = ref->force || force_update;
1462                 int reject_reason = 0;
1463
1464                 if (ref->peer_ref)
1465                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1466                 else if (!send_mirror)
1467                         continue;
1468
1469                 ref->deletion = is_null_sha1(ref->new_sha1);
1470                 if (!ref->deletion &&
1471                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1472                         ref->status = REF_STATUS_UPTODATE;
1473                         continue;
1474                 }
1475
1476                 /*
1477                  * Bypass the usual "must fast-forward" check but
1478                  * replace it with a weaker "the old value must be
1479                  * this value we observed".  If the remote ref has
1480                  * moved and is now different from what we expect,
1481                  * reject any push.
1482                  *
1483                  * It also is an error if the user told us to check
1484                  * with the remote-tracking branch to find the value
1485                  * to expect, but we did not have such a tracking
1486                  * branch.
1487                  */
1488                 if (ref->expect_old_sha1) {
1489                         if (ref->expect_old_no_trackback ||
1490                             hashcmp(ref->old_sha1, ref->old_sha1_expect))
1491                                 reject_reason = REF_STATUS_REJECT_STALE;
1492                 }
1493
1494                 /*
1495                  * The usual "must fast-forward" rules.
1496                  *
1497                  * Decide whether an individual refspec A:B can be
1498                  * pushed.  The push will succeed if any of the
1499                  * following are true:
1500                  *
1501                  * (1) the remote reference B does not exist
1502                  *
1503                  * (2) the remote reference B is being removed (i.e.,
1504                  *     pushing :B where no source is specified)
1505                  *
1506                  * (3) the destination is not under refs/tags/, and
1507                  *     if the old and new value is a commit, the new
1508                  *     is a descendant of the old.
1509                  *
1510                  * (4) it is forced using the +A:B notation, or by
1511                  *     passing the --force argument
1512                  */
1513
1514                 else if (!ref->deletion && !is_null_sha1(ref->old_sha1)) {
1515                         if (starts_with(ref->name, "refs/tags/"))
1516                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1517                         else if (!has_sha1_file(ref->old_sha1))
1518                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1519                         else if (!lookup_commit_reference_gently(ref->old_sha1, 1) ||
1520                                  !lookup_commit_reference_gently(ref->new_sha1, 1))
1521                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1522                         else if (!ref_newer(ref->new_sha1, ref->old_sha1))
1523                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1524                 }
1525
1526                 /*
1527                  * "--force" will defeat any rejection implemented
1528                  * by the rules above.
1529                  */
1530                 if (!force_ref_update)
1531                         ref->status = reject_reason;
1532                 else if (reject_reason)
1533                         ref->forced_update = 1;
1534         }
1535 }
1536
1537 struct branch *branch_get(const char *name)
1538 {
1539         struct branch *ret;
1540
1541         read_config();
1542         if (!name || !*name || !strcmp(name, "HEAD"))
1543                 ret = current_branch;
1544         else
1545                 ret = make_branch(name, 0);
1546         if (ret && ret->remote_name) {
1547                 ret->remote = remote_get(ret->remote_name);
1548                 if (ret->merge_nr) {
1549                         int i;
1550                         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1551                         for (i = 0; i < ret->merge_nr; i++) {
1552                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1553                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1554                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1555                                     && !strcmp(ret->remote_name, "."))
1556                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1557                         }
1558                 }
1559         }
1560         return ret;
1561 }
1562
1563 int branch_has_merge_config(struct branch *branch)
1564 {
1565         return branch && !!branch->merge;
1566 }
1567
1568 int branch_merge_matches(struct branch *branch,
1569                                  int i,
1570                                  const char *refname)
1571 {
1572         if (!branch || i < 0 || i >= branch->merge_nr)
1573                 return 0;
1574         return refname_match(branch->merge[i]->src, refname, ref_fetch_rules);
1575 }
1576
1577 static int ignore_symref_update(const char *refname)
1578 {
1579         unsigned char sha1[20];
1580         int flag;
1581
1582         if (!resolve_ref_unsafe(refname, sha1, 0, &flag))
1583                 return 0; /* non-existing refs are OK */
1584         return (flag & REF_ISSYMREF);
1585 }
1586
1587 /*
1588  * Create and return a list of (struct ref) consisting of copies of
1589  * each remote_ref that matches refspec.  refspec must be a pattern.
1590  * Fill in the copies' peer_ref to describe the local tracking refs to
1591  * which they map.  Omit any references that would map to an existing
1592  * local symbolic ref.
1593  */
1594 static struct ref *get_expanded_map(const struct ref *remote_refs,
1595                                     const struct refspec *refspec)
1596 {
1597         const struct ref *ref;
1598         struct ref *ret = NULL;
1599         struct ref **tail = &ret;
1600
1601         for (ref = remote_refs; ref; ref = ref->next) {
1602                 char *expn_name = NULL;
1603
1604                 if (strchr(ref->name, '^'))
1605                         continue; /* a dereference item */
1606                 if (match_name_with_pattern(refspec->src, ref->name,
1607                                             refspec->dst, &expn_name) &&
1608                     !ignore_symref_update(expn_name)) {
1609                         struct ref *cpy = copy_ref(ref);
1610
1611                         cpy->peer_ref = alloc_ref(expn_name);
1612                         if (refspec->force)
1613                                 cpy->peer_ref->force = 1;
1614                         *tail = cpy;
1615                         tail = &cpy->next;
1616                 }
1617                 free(expn_name);
1618         }
1619
1620         return ret;
1621 }
1622
1623 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1624 {
1625         const struct ref *ref;
1626         for (ref = refs; ref; ref = ref->next) {
1627                 if (refname_match(name, ref->name, ref_fetch_rules))
1628                         return ref;
1629         }
1630         return NULL;
1631 }
1632
1633 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1634 {
1635         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1636
1637         if (!ref)
1638                 return NULL;
1639
1640         return copy_ref(ref);
1641 }
1642
1643 static struct ref *get_local_ref(const char *name)
1644 {
1645         if (!name || name[0] == '\0')
1646                 return NULL;
1647
1648         if (starts_with(name, "refs/"))
1649                 return alloc_ref(name);
1650
1651         if (starts_with(name, "heads/") ||
1652             starts_with(name, "tags/") ||
1653             starts_with(name, "remotes/"))
1654                 return alloc_ref_with_prefix("refs/", 5, name);
1655
1656         return alloc_ref_with_prefix("refs/heads/", 11, name);
1657 }
1658
1659 int get_fetch_map(const struct ref *remote_refs,
1660                   const struct refspec *refspec,
1661                   struct ref ***tail,
1662                   int missing_ok)
1663 {
1664         struct ref *ref_map, **rmp;
1665
1666         if (refspec->pattern) {
1667                 ref_map = get_expanded_map(remote_refs, refspec);
1668         } else {
1669                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1670
1671                 if (refspec->exact_sha1) {
1672                         ref_map = alloc_ref(name);
1673                         get_sha1_hex(name, ref_map->old_sha1);
1674                 } else {
1675                         ref_map = get_remote_ref(remote_refs, name);
1676                 }
1677                 if (!missing_ok && !ref_map)
1678                         die("Couldn't find remote ref %s", name);
1679                 if (ref_map) {
1680                         ref_map->peer_ref = get_local_ref(refspec->dst);
1681                         if (ref_map->peer_ref && refspec->force)
1682                                 ref_map->peer_ref->force = 1;
1683                 }
1684         }
1685
1686         for (rmp = &ref_map; *rmp; ) {
1687                 if ((*rmp)->peer_ref) {
1688                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1689                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1690                                 struct ref *ignore = *rmp;
1691                                 error("* Ignoring funny ref '%s' locally",
1692                                       (*rmp)->peer_ref->name);
1693                                 *rmp = (*rmp)->next;
1694                                 free(ignore->peer_ref);
1695                                 free(ignore);
1696                                 continue;
1697                         }
1698                 }
1699                 rmp = &((*rmp)->next);
1700         }
1701
1702         if (ref_map)
1703                 tail_link_ref(ref_map, tail);
1704
1705         return 0;
1706 }
1707
1708 int resolve_remote_symref(struct ref *ref, struct ref *list)
1709 {
1710         if (!ref->symref)
1711                 return 0;
1712         for (; list; list = list->next)
1713                 if (!strcmp(ref->symref, list->name)) {
1714                         hashcpy(ref->old_sha1, list->old_sha1);
1715                         return 0;
1716                 }
1717         return 1;
1718 }
1719
1720 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1721 {
1722         while (list) {
1723                 struct commit_list *temp = list;
1724                 temp->item->object.flags &= ~mark;
1725                 list = temp->next;
1726                 free(temp);
1727         }
1728 }
1729
1730 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1731 {
1732         struct object *o;
1733         struct commit *old, *new;
1734         struct commit_list *list, *used;
1735         int found = 0;
1736
1737         /*
1738          * Both new and old must be commit-ish and new is descendant of
1739          * old.  Otherwise we require --force.
1740          */
1741         o = deref_tag(parse_object(old_sha1), NULL, 0);
1742         if (!o || o->type != OBJ_COMMIT)
1743                 return 0;
1744         old = (struct commit *) o;
1745
1746         o = deref_tag(parse_object(new_sha1), NULL, 0);
1747         if (!o || o->type != OBJ_COMMIT)
1748                 return 0;
1749         new = (struct commit *) o;
1750
1751         if (parse_commit(new) < 0)
1752                 return 0;
1753
1754         used = list = NULL;
1755         commit_list_insert(new, &list);
1756         while (list) {
1757                 new = pop_most_recent_commit(&list, TMP_MARK);
1758                 commit_list_insert(new, &used);
1759                 if (new == old) {
1760                         found = 1;
1761                         break;
1762                 }
1763         }
1764         unmark_and_free(list, TMP_MARK);
1765         unmark_and_free(used, TMP_MARK);
1766         return found;
1767 }
1768
1769 /*
1770  * Compare a branch with its upstream, and save their differences (number
1771  * of commits) in *num_ours and *num_theirs.
1772  *
1773  * Return 0 if branch has no upstream (no base), -1 if upstream is missing
1774  * (with "gone" base), otherwise 1 (with base).
1775  */
1776 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1777 {
1778         unsigned char sha1[20];
1779         struct commit *ours, *theirs;
1780         char symmetric[84];
1781         struct rev_info revs;
1782         const char *rev_argv[10], *base;
1783         int rev_argc;
1784
1785         /* Cannot stat unless we are marked to build on top of somebody else. */
1786         if (!branch ||
1787             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1788                 return 0;
1789
1790         /* Cannot stat if what we used to build on no longer exists */
1791         base = branch->merge[0]->dst;
1792         if (read_ref(base, sha1))
1793                 return -1;
1794         theirs = lookup_commit_reference(sha1);
1795         if (!theirs)
1796                 return -1;
1797
1798         if (read_ref(branch->refname, sha1))
1799                 return -1;
1800         ours = lookup_commit_reference(sha1);
1801         if (!ours)
1802                 return -1;
1803
1804         /* are we the same? */
1805         if (theirs == ours) {
1806                 *num_theirs = *num_ours = 0;
1807                 return 1;
1808         }
1809
1810         /* Run "rev-list --left-right ours...theirs" internally... */
1811         rev_argc = 0;
1812         rev_argv[rev_argc++] = NULL;
1813         rev_argv[rev_argc++] = "--left-right";
1814         rev_argv[rev_argc++] = symmetric;
1815         rev_argv[rev_argc++] = "--";
1816         rev_argv[rev_argc] = NULL;
1817
1818         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1819         strcpy(symmetric + 40, "...");
1820         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1821
1822         init_revisions(&revs, NULL);
1823         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1824         prepare_revision_walk(&revs);
1825
1826         /* ... and count the commits on each side. */
1827         *num_ours = 0;
1828         *num_theirs = 0;
1829         while (1) {
1830                 struct commit *c = get_revision(&revs);
1831                 if (!c)
1832                         break;
1833                 if (c->object.flags & SYMMETRIC_LEFT)
1834                         (*num_ours)++;
1835                 else
1836                         (*num_theirs)++;
1837         }
1838
1839         /* clear object flags smudged by the above traversal */
1840         clear_commit_marks(ours, ALL_REV_FLAGS);
1841         clear_commit_marks(theirs, ALL_REV_FLAGS);
1842         return 1;
1843 }
1844
1845 /*
1846  * Return true when there is anything to report, otherwise false.
1847  */
1848 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1849 {
1850         int ours, theirs;
1851         const char *base;
1852         int upstream_is_gone = 0;
1853
1854         switch (stat_tracking_info(branch, &ours, &theirs)) {
1855         case 0:
1856                 /* no base */
1857                 return 0;
1858         case -1:
1859                 /* with "gone" base */
1860                 upstream_is_gone = 1;
1861                 break;
1862         default:
1863                 /* with base */
1864                 break;
1865         }
1866
1867         base = branch->merge[0]->dst;
1868         base = shorten_unambiguous_ref(base, 0);
1869         if (upstream_is_gone) {
1870                 strbuf_addf(sb,
1871                         _("Your branch is based on '%s', but the upstream is gone.\n"),
1872                         base);
1873                 if (advice_status_hints)
1874                         strbuf_addf(sb,
1875                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
1876         } else if (!ours && !theirs) {
1877                 strbuf_addf(sb,
1878                         _("Your branch is up-to-date with '%s'.\n"),
1879                         base);
1880         } else if (!theirs) {
1881                 strbuf_addf(sb,
1882                         Q_("Your branch is ahead of '%s' by %d commit.\n",
1883                            "Your branch is ahead of '%s' by %d commits.\n",
1884                            ours),
1885                         base, ours);
1886                 if (advice_status_hints)
1887                         strbuf_addf(sb,
1888                                 _("  (use \"git push\" to publish your local commits)\n"));
1889         } else if (!ours) {
1890                 strbuf_addf(sb,
1891                         Q_("Your branch is behind '%s' by %d commit, "
1892                                "and can be fast-forwarded.\n",
1893                            "Your branch is behind '%s' by %d commits, "
1894                                "and can be fast-forwarded.\n",
1895                            theirs),
1896                         base, theirs);
1897                 if (advice_status_hints)
1898                         strbuf_addf(sb,
1899                                 _("  (use \"git pull\" to update your local branch)\n"));
1900         } else {
1901                 strbuf_addf(sb,
1902                         Q_("Your branch and '%s' have diverged,\n"
1903                                "and have %d and %d different commit each, "
1904                                "respectively.\n",
1905                            "Your branch and '%s' have diverged,\n"
1906                                "and have %d and %d different commits each, "
1907                                "respectively.\n",
1908                            theirs),
1909                         base, ours, theirs);
1910                 if (advice_status_hints)
1911                         strbuf_addf(sb,
1912                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
1913         }
1914         return 1;
1915 }
1916
1917 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1918 {
1919         struct ref ***local_tail = cb_data;
1920         struct ref *ref;
1921         int len;
1922
1923         /* we already know it starts with refs/ to get here */
1924         if (check_refname_format(refname + 5, 0))
1925                 return 0;
1926
1927         len = strlen(refname) + 1;
1928         ref = xcalloc(1, sizeof(*ref) + len);
1929         hashcpy(ref->new_sha1, sha1);
1930         memcpy(ref->name, refname, len);
1931         **local_tail = ref;
1932         *local_tail = &ref->next;
1933         return 0;
1934 }
1935
1936 struct ref *get_local_heads(void)
1937 {
1938         struct ref *local_refs = NULL, **local_tail = &local_refs;
1939         for_each_ref(one_local_ref, &local_tail);
1940         return local_refs;
1941 }
1942
1943 struct ref *guess_remote_head(const struct ref *head,
1944                               const struct ref *refs,
1945                               int all)
1946 {
1947         const struct ref *r;
1948         struct ref *list = NULL;
1949         struct ref **tail = &list;
1950
1951         if (!head)
1952                 return NULL;
1953
1954         /*
1955          * Some transports support directly peeking at
1956          * where HEAD points; if that is the case, then
1957          * we don't have to guess.
1958          */
1959         if (head->symref)
1960                 return copy_ref(find_ref_by_name(refs, head->symref));
1961
1962         /* If refs/heads/master could be right, it is. */
1963         if (!all) {
1964                 r = find_ref_by_name(refs, "refs/heads/master");
1965                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1966                         return copy_ref(r);
1967         }
1968
1969         /* Look for another ref that points there */
1970         for (r = refs; r; r = r->next) {
1971                 if (r != head &&
1972                     starts_with(r->name, "refs/heads/") &&
1973                     !hashcmp(r->old_sha1, head->old_sha1)) {
1974                         *tail = copy_ref(r);
1975                         tail = &((*tail)->next);
1976                         if (!all)
1977                                 break;
1978                 }
1979         }
1980
1981         return list;
1982 }
1983
1984 struct stale_heads_info {
1985         struct string_list *ref_names;
1986         struct ref **stale_refs_tail;
1987         struct refspec *refs;
1988         int ref_count;
1989 };
1990
1991 static int get_stale_heads_cb(const char *refname,
1992         const unsigned char *sha1, int flags, void *cb_data)
1993 {
1994         struct stale_heads_info *info = cb_data;
1995         struct refspec query;
1996         memset(&query, 0, sizeof(struct refspec));
1997         query.dst = (char *)refname;
1998
1999         if (query_refspecs(info->refs, info->ref_count, &query))
2000                 return 0; /* No matches */
2001
2002         /*
2003          * If we did find a suitable refspec and it's not a symref and
2004          * it's not in the list of refs that currently exist in that
2005          * remote we consider it to be stale.
2006          */
2007         if (!((flags & REF_ISSYMREF) ||
2008               string_list_has_string(info->ref_names, query.src))) {
2009                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2010                 hashcpy(ref->new_sha1, sha1);
2011         }
2012
2013         free(query.src);
2014         return 0;
2015 }
2016
2017 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
2018 {
2019         struct ref *ref, *stale_refs = NULL;
2020         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2021         struct stale_heads_info info;
2022         info.ref_names = &ref_names;
2023         info.stale_refs_tail = &stale_refs;
2024         info.refs = refs;
2025         info.ref_count = ref_count;
2026         for (ref = fetch_map; ref; ref = ref->next)
2027                 string_list_append(&ref_names, ref->name);
2028         sort_string_list(&ref_names);
2029         for_each_ref(get_stale_heads_cb, &info);
2030         string_list_clear(&ref_names, 0);
2031         return stale_refs;
2032 }
2033
2034 /*
2035  * Compare-and-swap
2036  */
2037 void clear_cas_option(struct push_cas_option *cas)
2038 {
2039         int i;
2040
2041         for (i = 0; i < cas->nr; i++)
2042                 free(cas->entry[i].refname);
2043         free(cas->entry);
2044         memset(cas, 0, sizeof(*cas));
2045 }
2046
2047 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2048                                       const char *refname,
2049                                       size_t refnamelen)
2050 {
2051         struct push_cas *entry;
2052         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2053         entry = &cas->entry[cas->nr++];
2054         memset(entry, 0, sizeof(*entry));
2055         entry->refname = xmemdupz(refname, refnamelen);
2056         return entry;
2057 }
2058
2059 int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2060 {
2061         const char *colon;
2062         struct push_cas *entry;
2063
2064         if (unset) {
2065                 /* "--no-<option>" */
2066                 clear_cas_option(cas);
2067                 return 0;
2068         }
2069
2070         if (!arg) {
2071                 /* just "--<option>" */
2072                 cas->use_tracking_for_rest = 1;
2073                 return 0;
2074         }
2075
2076         /* "--<option>=refname" or "--<option>=refname:value" */
2077         colon = strchrnul(arg, ':');
2078         entry = add_cas_entry(cas, arg, colon - arg);
2079         if (!*colon)
2080                 entry->use_tracking = 1;
2081         else if (get_sha1(colon + 1, entry->expect))
2082                 return error("cannot parse expected object name '%s'", colon + 1);
2083         return 0;
2084 }
2085
2086 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2087 {
2088         return parse_push_cas_option(opt->value, arg, unset);
2089 }
2090
2091 int is_empty_cas(const struct push_cas_option *cas)
2092 {
2093         return !cas->use_tracking_for_rest && !cas->nr;
2094 }
2095
2096 /*
2097  * Look at remote.fetch refspec and see if we have a remote
2098  * tracking branch for the refname there.  Fill its current
2099  * value in sha1[].
2100  * If we cannot do so, return negative to signal an error.
2101  */
2102 static int remote_tracking(struct remote *remote, const char *refname,
2103                            unsigned char sha1[20])
2104 {
2105         char *dst;
2106
2107         dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
2108         if (!dst)
2109                 return -1; /* no tracking ref for refname at remote */
2110         if (read_ref(dst, sha1))
2111                 return -1; /* we know what the tracking ref is but we cannot read it */
2112         return 0;
2113 }
2114
2115 static void apply_cas(struct push_cas_option *cas,
2116                       struct remote *remote,
2117                       struct ref *ref)
2118 {
2119         int i;
2120
2121         /* Find an explicit --<option>=<name>[:<value>] entry */
2122         for (i = 0; i < cas->nr; i++) {
2123                 struct push_cas *entry = &cas->entry[i];
2124                 if (!refname_match(entry->refname, ref->name, ref_rev_parse_rules))
2125                         continue;
2126                 ref->expect_old_sha1 = 1;
2127                 if (!entry->use_tracking)
2128                         hashcpy(ref->old_sha1_expect, cas->entry[i].expect);
2129                 else if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2130                         ref->expect_old_no_trackback = 1;
2131                 return;
2132         }
2133
2134         /* Are we using "--<option>" to cover all? */
2135         if (!cas->use_tracking_for_rest)
2136                 return;
2137
2138         ref->expect_old_sha1 = 1;
2139         if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2140                 ref->expect_old_no_trackback = 1;
2141 }
2142
2143 void apply_push_cas(struct push_cas_option *cas,
2144                     struct remote *remote,
2145                     struct ref *remote_refs)
2146 {
2147         struct ref *ref;
2148         for (ref = remote_refs; ref; ref = ref->next)
2149                 apply_cas(cas, remote, ref);
2150 }