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 *branch_pushremote_name;
  53 static const char *pushremote_name;
  54 static int explicit_default_remote_name;
  55
  56 static struct rewrites rewrites;
  57 static struct rewrites rewrites_push;
  58
  59 #define BUF_SIZE (2048)
  60 static char buffer[BUF_SIZE];
  61
  62 static int valid_remote(const struct remote *remote)
  63 {
  64         return (!!remote->url) || (!!remote->foreign_vcs);
  65 }
  66
  67 static const char *alias_url(const char *url, struct rewrites *r)
  68 {
  69         int i, j;
  70         char *ret;
  71         struct counted_string *longest;
  72         int longest_i;
  73
  74         longest = NULL;
  75         longest_i = -1;
  76         for (i = 0; i < r->rewrite_nr; i++) {
  77                 if (!r->rewrite[i])
  78                         continue;
  79                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  80                         if (starts_with(url, r->rewrite[i]->instead_of[j].s) &&
  81                             (!longest ||
  82                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  83                                 longest = &(r->rewrite[i]->instead_of[j]);
  84                                 longest_i = i;
  85                         }
  86                 }
  87         }
  88         if (!longest)
  89                 return url;
  90
  91         ret = xmalloc(r->rewrite[longest_i]->baselen +
  92                      (strlen(url) - longest->len) + 1);
  93         strcpy(ret, r->rewrite[longest_i]->base);
  94         strcpy(ret + r->rewrite[longest_i]->baselen, url + longest->len);
  95         return ret;
  96 }
  97
  98 static void add_push_refspec(struct remote *remote, const char *ref)
  99 {
 100         ALLOC_GROW(remote->push_refspec,
 101                    remote->push_refspec_nr + 1,
 102                    remote->push_refspec_alloc);
 103         remote->push_refspec[remote->push_refspec_nr++] = ref;
 104 }
 105
 106 static void add_fetch_refspec(struct remote *remote, const char *ref)
 107 {
 108         ALLOC_GROW(remote->fetch_refspec,
 109                    remote->fetch_refspec_nr + 1,
 110                    remote->fetch_refspec_alloc);
 111         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
 112 }
 113
 114 static void add_url(struct remote *remote, const char *url)
 115 {
 116         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
 117         remote->url[remote->url_nr++] = url;
 118 }
 119
 120 static void add_pushurl(struct remote *remote, const char *pushurl)
 121 {
 122         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
 123         remote->pushurl[remote->pushurl_nr++] = pushurl;
 124 }
 125
 126 static void add_pushurl_alias(struct remote *remote, const char *url)
 127 {
 128         const char *pushurl = alias_url(url, &rewrites_push);
 129         if (pushurl != url)
 130                 add_pushurl(remote, pushurl);
 131 }
 132
 133 static void add_url_alias(struct remote *remote, const char *url)
 134 {
 135         add_url(remote, alias_url(url, &rewrites));
 136         add_pushurl_alias(remote, url);
 137 }
 138
 139 static struct remote *make_remote(const char *name, int len)
 140 {
 141         struct remote *ret;
 142         int i;
 143
 144         for (i = 0; i < remotes_nr; i++) {
 145                 if (len ? (!strncmp(name, remotes[i]->name, len) &&
 146                            !remotes[i]->name[len]) :
 147                     !strcmp(name, remotes[i]->name))
 148                         return remotes[i];
 149         }
 150
 151         ret = xcalloc(1, sizeof(struct remote));
 152         ret->prune = -1;  /* unspecified */
 153         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 154         remotes[remotes_nr++] = ret;
 155         if (len)
 156                 ret->name = xstrndup(name, len);
 157         else
 158                 ret->name = xstrdup(name);
 159         return ret;
 160 }
 161
 162 static void add_merge(struct branch *branch, const char *name)
 163 {
 164         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 165                    branch->merge_alloc);
 166         branch->merge_name[branch->merge_nr++] = name;
 167 }
 168
 169 static struct branch *make_branch(const char *name, int len)
 170 {
 171         struct branch *ret;
 172         int i;
 173         char *refname;
 174
 175         for (i = 0; i < branches_nr; i++) {
 176                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 177                            !branches[i]->name[len]) :
 178                     !strcmp(name, branches[i]->name))
 179                         return branches[i];
 180         }
 181
 182         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 183         ret = xcalloc(1, sizeof(struct branch));
 184         branches[branches_nr++] = ret;
 185         if (len)
 186                 ret->name = xstrndup(name, len);
 187         else
 188                 ret->name = xstrdup(name);
 189         refname = xmalloc(strlen(name) + strlen("refs/heads/") + 1);
 190         strcpy(refname, "refs/heads/");
 191         strcpy(refname + strlen("refs/heads/"), ret->name);
 192         ret->refname = refname;
 193
 194         return ret;
 195 }
 196
 197 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 198 {
 199         struct rewrite *ret;
 200         int i;
 201
 202         for (i = 0; i < r->rewrite_nr; i++) {
 203                 if (len
 204                     ? (len == r->rewrite[i]->baselen &&
 205                        !strncmp(base, r->rewrite[i]->base, len))
 206                     : !strcmp(base, r->rewrite[i]->base))
 207                         return r->rewrite[i];
 208         }
 209
 210         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 211         ret = xcalloc(1, sizeof(struct rewrite));
 212         r->rewrite[r->rewrite_nr++] = ret;
 213         if (len) {
 214                 ret->base = xstrndup(base, len);
 215                 ret->baselen = len;
 216         }
 217         else {
 218                 ret->base = xstrdup(base);
 219                 ret->baselen = strlen(base);
 220         }
 221         return ret;
 222 }
 223
 224 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 225 {
 226         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 227         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 228         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 229         rewrite->instead_of_nr++;
 230 }
 231
 232 static void read_remotes_file(struct remote *remote)
 233 {
 234         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 235
 236         if (!f)
 237                 return;
 238         remote->origin = REMOTE_REMOTES;
 239         while (fgets(buffer, BUF_SIZE, f)) {
 240                 int value_list;
 241                 char *s, *p;
 242
 243                 if (starts_with(buffer, "URL:")) {
 244                         value_list = 0;
 245                         s = buffer + 4;
 246                 } else if (starts_with(buffer, "Push:")) {
 247                         value_list = 1;
 248                         s = buffer + 5;
 249                 } else if (starts_with(buffer, "Pull:")) {
 250                         value_list = 2;
 251                         s = buffer + 5;
 252                 } else
 253                         continue;
 254
 255                 while (isspace(*s))
 256                         s++;
 257                 if (!*s)
 258                         continue;
 259
 260                 p = s + strlen(s);
 261                 while (isspace(p[-1]))
 262                         *--p = 0;
 263
 264                 switch (value_list) {
 265                 case 0:
 266                         add_url_alias(remote, xstrdup(s));
 267                         break;
 268                 case 1:
 269                         add_push_refspec(remote, xstrdup(s));
 270                         break;
 271                 case 2:
 272                         add_fetch_refspec(remote, xstrdup(s));
 273                         break;
 274                 }
 275         }
 276         fclose(f);
 277 }
 278
 279 static void read_branches_file(struct remote *remote)
 280 {
 281         char *frag;
 282         struct strbuf branch = STRBUF_INIT;
 283         int n = 1000;
 284         FILE *f = fopen(git_path("branches/%.*s", n, remote->name), "r");
 285         char *s, *p;
 286         int len;
 287
 288         if (!f)
 289                 return;
 290         s = fgets(buffer, BUF_SIZE, f);
 291         fclose(f);
 292         if (!s)
 293                 return;
 294         while (isspace(*s))
 295                 s++;
 296         if (!*s)
 297                 return;
 298         remote->origin = REMOTE_BRANCHES;
 299         p = s + strlen(s);
 300         while (isspace(p[-1]))
 301                 *--p = 0;
 302         len = p - s;
 303         p = xmalloc(len + 1);
 304         strcpy(p, s);
 305
 306         /*
 307          * The branches file would have URL and optionally
 308          * #branch specified.  The "master" (or specified) branch is
 309          * fetched and stored in the local branch of the same name.
 310          */
 311         frag = strchr(p, '#');
 312         if (frag) {
 313                 *(frag++) = '\0';
 314                 strbuf_addf(&branch, "refs/heads/%s", frag);
 315         } else
 316                 strbuf_addstr(&branch, "refs/heads/master");
 317
 318         strbuf_addf(&branch, ":refs/heads/%s", remote->name);
 319         add_url_alias(remote, p);
 320         add_fetch_refspec(remote, strbuf_detach(&branch, NULL));
 321         /*
 322          * Cogito compatible push: push current HEAD to remote #branch
 323          * (master if missing)
 324          */
 325         strbuf_init(&branch, 0);
 326         strbuf_addstr(&branch, "HEAD");
 327         if (frag)
 328                 strbuf_addf(&branch, ":refs/heads/%s", frag);
 329         else
 330                 strbuf_addstr(&branch, ":refs/heads/master");
 331         add_push_refspec(remote, strbuf_detach(&branch, NULL));
 332         remote->fetch_tags = 1; /* always auto-follow */
 333 }
 334
 335 static int handle_config(const char *key, const char *value, void *cb)
 336 {
 337         const char *name;
 338         const char *subkey;
 339         struct remote *remote;
 340         struct branch *branch;
 341         if (starts_with(key, "branch.")) {
 342                 name = key + 7;
 343                 subkey = strrchr(name, '.');
 344                 if (!subkey)
 345                         return 0;
 346                 branch = make_branch(name, subkey - name);
 347                 if (!strcmp(subkey, ".remote")) {
 348                         if (git_config_string(&branch->remote_name, key, value))
 349                                 return -1;
 350                         if (branch == current_branch) {
 351                                 default_remote_name = branch->remote_name;
 352                                 explicit_default_remote_name = 1;
 353                         }
 354                 } else if (!strcmp(subkey, ".pushremote")) {
 355                         if (branch == current_branch)
 356                                 if (git_config_string(&branch_pushremote_name, key, value))
 357                                         return -1;
 358                 } else if (!strcmp(subkey, ".merge")) {
 359                         if (!value)
 360                                 return config_error_nonbool(key);
 361                         add_merge(branch, xstrdup(value));
 362                 }
 363                 return 0;
 364         }
 365         if (starts_with(key, "url.")) {
 366                 struct rewrite *rewrite;
 367                 name = key + 4;
 368                 subkey = strrchr(name, '.');
 369                 if (!subkey)
 370                         return 0;
 371                 if (!strcmp(subkey, ".insteadof")) {
 372                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 373                         if (!value)
 374                                 return config_error_nonbool(key);
 375                         add_instead_of(rewrite, xstrdup(value));
 376                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 377                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 378                         if (!value)
 379                                 return config_error_nonbool(key);
 380                         add_instead_of(rewrite, xstrdup(value));
 381                 }
 382         }
 383
 384         if (!starts_with(key,  "remote."))
 385                 return 0;
 386         name = key + 7;
 387
 388         /* Handle remote.* variables */
 389         if (!strcmp(name, "pushdefault"))
 390                 return git_config_string(&pushremote_name, key, value);
 391
 392         /* Handle remote.<name>.* variables */
 393         if (*name == '/') {
 394                 warning("Config remote shorthand cannot begin with '/': %s",
 395                         name);
 396                 return 0;
 397         }
 398         subkey = strrchr(name, '.');
 399         if (!subkey)
 400                 return 0;
 401         remote = make_remote(name, subkey - name);
 402         remote->origin = REMOTE_CONFIG;
 403         if (!strcmp(subkey, ".mirror"))
 404                 remote->mirror = git_config_bool(key, value);
 405         else if (!strcmp(subkey, ".skipdefaultupdate"))
 406                 remote->skip_default_update = git_config_bool(key, value);
 407         else if (!strcmp(subkey, ".skipfetchall"))
 408                 remote->skip_default_update = git_config_bool(key, value);
 409         else if (!strcmp(subkey, ".prune"))
 410                 remote->prune = git_config_bool(key, value);
 411         else if (!strcmp(subkey, ".url")) {
 412                 const char *v;
 413                 if (git_config_string(&v, key, value))
 414                         return -1;
 415                 add_url(remote, v);
 416         } else if (!strcmp(subkey, ".pushurl")) {
 417                 const char *v;
 418                 if (git_config_string(&v, key, value))
 419                         return -1;
 420                 add_pushurl(remote, v);
 421         } else if (!strcmp(subkey, ".push")) {
 422                 const char *v;
 423                 if (git_config_string(&v, key, value))
 424                         return -1;
 425                 add_push_refspec(remote, v);
 426         } else if (!strcmp(subkey, ".fetch")) {
 427                 const char *v;
 428                 if (git_config_string(&v, key, value))
 429                         return -1;
 430                 add_fetch_refspec(remote, v);
 431         } else if (!strcmp(subkey, ".receivepack")) {
 432                 const char *v;
 433                 if (git_config_string(&v, key, value))
 434                         return -1;
 435                 if (!remote->receivepack)
 436                         remote->receivepack = v;
 437                 else
 438                         error("more than one receivepack given, using the first");
 439         } else if (!strcmp(subkey, ".uploadpack")) {
 440                 const char *v;
 441                 if (git_config_string(&v, key, value))
 442                         return -1;
 443                 if (!remote->uploadpack)
 444                         remote->uploadpack = v;
 445                 else
 446                         error("more than one uploadpack given, using the first");
 447         } else if (!strcmp(subkey, ".tagopt")) {
 448                 if (!strcmp(value, "--no-tags"))
 449                         remote->fetch_tags = -1;
 450                 else if (!strcmp(value, "--tags"))
 451                         remote->fetch_tags = 2;
 452         } else if (!strcmp(subkey, ".proxy")) {
 453                 return git_config_string((const char **)&remote->http_proxy,
 454                                          key, value);
 455         } else if (!strcmp(subkey, ".vcs")) {
 456                 return git_config_string(&remote->foreign_vcs, key, value);
 457         }
 458         return 0;
 459 }
 460
 461 static void alias_all_urls(void)
 462 {
 463         int i, j;
 464         for (i = 0; i < remotes_nr; i++) {
 465                 int add_pushurl_aliases;
 466                 if (!remotes[i])
 467                         continue;
 468                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 469                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 470                 }
 471                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 472                 for (j = 0; j < remotes[i]->url_nr; j++) {
 473                         if (add_pushurl_aliases)
 474                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 475                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 476                 }
 477         }
 478 }
 479
 480 static void read_config(void)
 481 {
 482         unsigned char sha1[20];
 483         const char *head_ref;
 484         int flag;
 485         if (default_remote_name) /* did this already */
 486                 return;
 487         default_remote_name = "origin";
 488         current_branch = NULL;
 489         head_ref = resolve_ref_unsafe("HEAD", sha1, 0, &flag);
 490         if (head_ref && (flag & REF_ISSYMREF) &&
 491             starts_with(head_ref, "refs/heads/")) {
 492                 current_branch =
 493                         make_branch(head_ref + strlen("refs/heads/"), 0);
 494         }
 495         git_config(handle_config, NULL);
 496         if (branch_pushremote_name) {
 497                 free((char *)pushremote_name);
 498                 pushremote_name = branch_pushremote_name;
 499         }
 500         alias_all_urls();
 501 }
 502
 503 /*
 504  * This function frees a refspec array.
 505  * Warning: code paths should be checked to ensure that the src
 506  *          and dst pointers are always freeable pointers as well
 507  *          as the refspec pointer itself.
 508  */
 509 static void free_refspecs(struct refspec *refspec, int nr_refspec)
 510 {
 511         int i;
 512
 513         if (!refspec)
 514                 return;
 515
 516         for (i = 0; i < nr_refspec; i++) {
 517                 free(refspec[i].src);
 518                 free(refspec[i].dst);
 519         }
 520         free(refspec);
 521 }
 522
 523 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 524 {
 525         int i;
 526         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 527
 528         for (i = 0; i < nr_refspec; i++) {
 529                 size_t llen;
 530                 int is_glob;
 531                 const char *lhs, *rhs;
 532                 int flags;
 533
 534                 is_glob = 0;
 535
 536                 lhs = refspec[i];
 537                 if (*lhs == '+') {
 538                         rs[i].force = 1;
 539                         lhs++;
 540                 }
 541
 542                 rhs = strrchr(lhs, ':');
 543
 544                 /*
 545                  * Before going on, special case ":" (or "+:") as a refspec
 546                  * for pushing matching refs.
 547                  */
 548                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
 549                         rs[i].matching = 1;
 550                         continue;
 551                 }
 552
 553                 if (rhs) {
 554                         size_t rlen = strlen(++rhs);
 555                         is_glob = (1 <= rlen && strchr(rhs, '*'));
 556                         rs[i].dst = xstrndup(rhs, rlen);
 557                 }
 558
 559                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 560                 if (1 <= llen && memchr(lhs, '*', llen)) {
 561                         if ((rhs && !is_glob) || (!rhs && fetch))
 562                                 goto invalid;
 563                         is_glob = 1;
 564                 } else if (rhs && is_glob) {
 565                         goto invalid;
 566                 }
 567
 568                 rs[i].pattern = is_glob;
 569                 rs[i].src = xstrndup(lhs, llen);
 570                 flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
 571
 572                 if (fetch) {
 573                         unsigned char unused[40];
 574
 575                         /* LHS */
 576                         if (!*rs[i].src)
 577                                 ; /* empty is ok; it means "HEAD" */
 578                         else if (llen == 40 && !get_sha1_hex(rs[i].src, unused))
 579                                 rs[i].exact_sha1 = 1; /* ok */
 580                         else if (!check_refname_format(rs[i].src, flags))
 581                                 ; /* valid looking ref is ok */
 582                         else
 583                                 goto invalid;
 584                         /* RHS */
 585                         if (!rs[i].dst)
 586                                 ; /* missing is ok; it is the same as empty */
 587                         else if (!*rs[i].dst)
 588                                 ; /* empty is ok; it means "do not store" */
 589                         else if (!check_refname_format(rs[i].dst, flags))
 590                                 ; /* valid looking ref is ok */
 591                         else
 592                                 goto invalid;
 593                 } else {
 594                         /*
 595                          * LHS
 596                          * - empty is allowed; it means delete.
 597                          * - when wildcarded, it must be a valid looking ref.
 598                          * - otherwise, it must be an extended SHA-1, but
 599                          *   there is no existing way to validate this.
 600                          */
 601                         if (!*rs[i].src)
 602                                 ; /* empty is ok */
 603                         else if (is_glob) {
 604                                 if (check_refname_format(rs[i].src, flags))
 605                                         goto invalid;
 606                         }
 607                         else
 608                                 ; /* anything goes, for now */
 609                         /*
 610                          * RHS
 611                          * - missing is allowed, but LHS then must be a
 612                          *   valid looking ref.
 613                          * - empty is not allowed.
 614                          * - otherwise it must be a valid looking ref.
 615                          */
 616                         if (!rs[i].dst) {
 617                                 if (check_refname_format(rs[i].src, flags))
 618                                         goto invalid;
 619                         } else if (!*rs[i].dst) {
 620                                 goto invalid;
 621                         } else {
 622                                 if (check_refname_format(rs[i].dst, flags))
 623                                         goto invalid;
 624                         }
 625                 }
 626         }
 627         return rs;
 628
 629  invalid:
 630         if (verify) {
 631                 /*
 632                  * nr_refspec must be greater than zero and i must be valid
 633                  * since it is only possible to reach this point from within
 634                  * the for loop above.
 635                  */
 636                 free_refspecs(rs, i+1);
 637                 return NULL;
 638         }
 639         die("Invalid refspec '%s'", refspec[i]);
 640 }
 641
 642 int valid_fetch_refspec(const char *fetch_refspec_str)
 643 {
 644         struct refspec *refspec;
 645
 646         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
 647         free_refspecs(refspec, 1);
 648         return !!refspec;
 649 }
 650
 651 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 652 {
 653         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 654 }
 655
 656 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 657 {
 658         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 659 }
 660
 661 void free_refspec(int nr_refspec, struct refspec *refspec)
 662 {
 663         int i;
 664         for (i = 0; i < nr_refspec; i++) {
 665                 free(refspec[i].src);
 666                 free(refspec[i].dst);
 667         }
 668         free(refspec);
 669 }
 670
 671 static int valid_remote_nick(const char *name)
 672 {
 673         if (!name[0] || is_dot_or_dotdot(name))
 674                 return 0;
 675         return !strchr(name, '/'); /* no slash */
 676 }
 677
 678 static struct remote *remote_get_1(const char *name, const char *pushremote_name)
 679 {
 680         struct remote *ret;
 681         int name_given = 0;
 682
 683         if (name)
 684                 name_given = 1;
 685         else {
 686                 if (pushremote_name) {
 687                         name = pushremote_name;
 688                         name_given = 1;
 689                 } else {
 690                         name = default_remote_name;
 691                         name_given = explicit_default_remote_name;
 692                 }
 693         }
 694
 695         ret = make_remote(name, 0);
 696         if (valid_remote_nick(name)) {
 697                 if (!valid_remote(ret))
 698                         read_remotes_file(ret);
 699                 if (!valid_remote(ret))
 700                         read_branches_file(ret);
 701         }
 702         if (name_given && !valid_remote(ret))
 703                 add_url_alias(ret, name);
 704         if (!valid_remote(ret))
 705                 return NULL;
 706         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 707         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 708         return ret;
 709 }
 710
 711 struct remote *remote_get(const char *name)
 712 {
 713         read_config();
 714         return remote_get_1(name, NULL);
 715 }
 716
 717 struct remote *pushremote_get(const char *name)
 718 {
 719         read_config();
 720         return remote_get_1(name, pushremote_name);
 721 }
 722
 723 int remote_is_configured(const char *name)
 724 {
 725         int i;
 726         read_config();
 727
 728         for (i = 0; i < remotes_nr; i++)
 729                 if (!strcmp(name, remotes[i]->name))
 730                         return 1;
 731         return 0;
 732 }
 733
 734 int for_each_remote(each_remote_fn fn, void *priv)
 735 {
 736         int i, result = 0;
 737         read_config();
 738         for (i = 0; i < remotes_nr && !result; i++) {
 739                 struct remote *r = remotes[i];
 740                 if (!r)
 741                         continue;
 742                 if (!r->fetch)
 743                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 744                                                        r->fetch_refspec);
 745                 if (!r->push)
 746                         r->push = parse_push_refspec(r->push_refspec_nr,
 747                                                      r->push_refspec);
 748                 result = fn(r, priv);
 749         }
 750         return result;
 751 }
 752
 753 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
 754 {
 755         if (strcmp(ref1->name, ref2->name)) {
 756                 if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 757                     ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
 758                         die(_("Cannot fetch both %s and %s to %s"),
 759                             ref1->name, ref2->name, ref2->peer_ref->name);
 760                 } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 761                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 762                         warning(_("%s usually tracks %s, not %s"),
 763                                 ref2->peer_ref->name, ref2->name, ref1->name);
 764                 } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
 765                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 766                         die(_("%s tracks both %s and %s"),
 767                             ref2->peer_ref->name, ref1->name, ref2->name);
 768                 } else {
 769                         /*
 770                          * This last possibility doesn't occur because
 771                          * FETCH_HEAD_IGNORE entries always appear at
 772                          * the end of the list.
 773                          */
 774                         die(_("Internal error"));
 775                 }
 776         }
 777         free(ref2->peer_ref);
 778         free(ref2);
 779 }
 780
 781 struct ref *ref_remove_duplicates(struct ref *ref_map)
 782 {
 783         struct string_list refs = STRING_LIST_INIT_NODUP;
 784         struct ref *retval = NULL;
 785         struct ref **p = &retval;
 786
 787         while (ref_map) {
 788                 struct ref *ref = ref_map;
 789
 790                 ref_map = ref_map->next;
 791                 ref->next = NULL;
 792
 793                 if (!ref->peer_ref) {
 794                         *p = ref;
 795                         p = &ref->next;
 796                 } else {
 797                         struct string_list_item *item =
 798                                 string_list_insert(&refs, ref->peer_ref->name);
 799
 800                         if (item->util) {
 801                                 /* Entry already existed */
 802                                 handle_duplicate((struct ref *)item->util, ref);
 803                         } else {
 804                                 *p = ref;
 805                                 p = &ref->next;
 806                                 item->util = ref;
 807                         }
 808                 }
 809         }
 810
 811         string_list_clear(&refs, 0);
 812         return retval;
 813 }
 814
 815 int remote_has_url(struct remote *remote, const char *url)
 816 {
 817         int i;
 818         for (i = 0; i < remote->url_nr; i++) {
 819                 if (!strcmp(remote->url[i], url))
 820                         return 1;
 821         }
 822         return 0;
 823 }
 824
 825 static int match_name_with_pattern(const char *key, const char *name,
 826                                    const char *value, char **result)
 827 {
 828         const char *kstar = strchr(key, '*');
 829         size_t klen;
 830         size_t ksuffixlen;
 831         size_t namelen;
 832         int ret;
 833         if (!kstar)
 834                 die("Key '%s' of pattern had no '*'", key);
 835         klen = kstar - key;
 836         ksuffixlen = strlen(kstar + 1);
 837         namelen = strlen(name);
 838         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 839                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 840         if (ret && value) {
 841                 const char *vstar = strchr(value, '*');
 842                 size_t vlen;
 843                 size_t vsuffixlen;
 844                 if (!vstar)
 845                         die("Value '%s' of pattern has no '*'", value);
 846                 vlen = vstar - value;
 847                 vsuffixlen = strlen(vstar + 1);
 848                 *result = xmalloc(vlen + vsuffixlen +
 849                                   strlen(name) -
 850                                   klen - ksuffixlen + 1);
 851                 strncpy(*result, value, vlen);
 852                 strncpy(*result + vlen,
 853                         name + klen, namelen - klen - ksuffixlen);
 854                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
 855                        vstar + 1);
 856         }
 857         return ret;
 858 }
 859
 860 int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
 861 {
 862         int i;
 863         int find_src = !query->src;
 864         const char *needle = find_src ? query->dst : query->src;
 865         char **result = find_src ? &query->src : &query->dst;
 866
 867         if (find_src && !query->dst)
 868                 return error("query_refspecs: need either src or dst");
 869
 870         for (i = 0; i < ref_count; i++) {
 871                 struct refspec *refspec = &refs[i];
 872                 const char *key = find_src ? refspec->dst : refspec->src;
 873                 const char *value = find_src ? refspec->src : refspec->dst;
 874
 875                 if (!refspec->dst)
 876                         continue;
 877                 if (refspec->pattern) {
 878                         if (match_name_with_pattern(key, needle, value, result)) {
 879                                 query->force = refspec->force;
 880                                 return 0;
 881                         }
 882                 } else if (!strcmp(needle, key)) {
 883                         *result = xstrdup(value);
 884                         query->force = refspec->force;
 885                         return 0;
 886                 }
 887         }
 888         return -1;
 889 }
 890
 891 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 892                      const char *name)
 893 {
 894         struct refspec query;
 895
 896         memset(&query, 0, sizeof(struct refspec));
 897         query.src = (char *)name;
 898
 899         if (query_refspecs(refspecs, nr_refspec, &query))
 900                 return NULL;
 901
 902         return query.dst;
 903 }
 904
 905 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 906 {
 907         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
 908 }
 909
 910 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 911                 const char *name)
 912 {
 913         size_t len = strlen(name);
 914         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 915         memcpy(ref->name, prefix, prefixlen);
 916         memcpy(ref->name + prefixlen, name, len);
 917         return ref;
 918 }
 919
 920 struct ref *alloc_ref(const char *name)
 921 {
 922         return alloc_ref_with_prefix("", 0, name);
 923 }
 924
 925 struct ref *copy_ref(const struct ref *ref)
 926 {
 927         struct ref *cpy;
 928         size_t len;
 929         if (!ref)
 930                 return NULL;
 931         len = strlen(ref->name);
 932         cpy = xmalloc(sizeof(struct ref) + len + 1);
 933         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 934         cpy->next = NULL;
 935         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 936         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 937         cpy->peer_ref = copy_ref(ref->peer_ref);
 938         return cpy;
 939 }
 940
 941 struct ref *copy_ref_list(const struct ref *ref)
 942 {
 943         struct ref *ret = NULL;
 944         struct ref **tail = &ret;
 945         while (ref) {
 946                 *tail = copy_ref(ref);
 947                 ref = ref->next;
 948                 tail = &((*tail)->next);
 949         }
 950         return ret;
 951 }
 952
 953 static void free_ref(struct ref *ref)
 954 {
 955         if (!ref)
 956                 return;
 957         free_ref(ref->peer_ref);
 958         free(ref->remote_status);
 959         free(ref->symref);
 960         free(ref);
 961 }
 962
 963 void free_refs(struct ref *ref)
 964 {
 965         struct ref *next;
 966         while (ref) {
 967                 next = ref->next;
 968                 free_ref(ref);
 969                 ref = next;
 970         }
 971 }
 972
 973 int ref_compare_name(const void *va, const void *vb)
 974 {
 975         const struct ref *a = va, *b = vb;
 976         return strcmp(a->name, b->name);
 977 }
 978
 979 static void *ref_list_get_next(const void *a)
 980 {
 981         return ((const struct ref *)a)->next;
 982 }
 983
 984 static void ref_list_set_next(void *a, void *next)
 985 {
 986         ((struct ref *)a)->next = next;
 987 }
 988
 989 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
 990 {
 991         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
 992 }
 993
 994 int count_refspec_match(const char *pattern,
 995                         struct ref *refs,
 996                         struct ref **matched_ref)
 997 {
 998         int patlen = strlen(pattern);
 999         struct ref *matched_weak = NULL;
1000         struct ref *matched = NULL;
1001         int weak_match = 0;
1002         int match = 0;
1003
1004         for (weak_match = match = 0; refs; refs = refs->next) {
1005                 char *name = refs->name;
1006                 int namelen = strlen(name);
1007
1008                 if (!refname_match(pattern, name))
1009                         continue;
1010
1011                 /* A match is "weak" if it is with refs outside
1012                  * heads or tags, and did not specify the pattern
1013                  * in full (e.g. "refs/remotes/origin/master") or at
1014                  * least from the toplevel (e.g. "remotes/origin/master");
1015                  * otherwise "git push $URL master" would result in
1016                  * ambiguity between remotes/origin/master and heads/master
1017                  * at the remote site.
1018                  */
1019                 if (namelen != patlen &&
1020                     patlen != namelen - 5 &&
1021                     !starts_with(name, "refs/heads/") &&
1022                     !starts_with(name, "refs/tags/")) {
1023                         /* We want to catch the case where only weak
1024                          * matches are found and there are multiple
1025                          * matches, and where more than one strong
1026                          * matches are found, as ambiguous.  One
1027                          * strong match with zero or more weak matches
1028                          * are acceptable as a unique match.
1029                          */
1030                         matched_weak = refs;
1031                         weak_match++;
1032                 }
1033                 else {
1034                         matched = refs;
1035                         match++;
1036                 }
1037         }
1038         if (!matched) {
1039                 *matched_ref = matched_weak;
1040                 return weak_match;
1041         }
1042         else {
1043                 *matched_ref = matched;
1044                 return match;
1045         }
1046 }
1047
1048 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1049 {
1050         **tail = ref;
1051         while (ref->next)
1052                 ref = ref->next;
1053         *tail = &ref->next;
1054 }
1055
1056 static struct ref *alloc_delete_ref(void)
1057 {
1058         struct ref *ref = alloc_ref("(delete)");
1059         hashclr(ref->new_sha1);
1060         return ref;
1061 }
1062
1063 static struct ref *try_explicit_object_name(const char *name)
1064 {
1065         unsigned char sha1[20];
1066         struct ref *ref;
1067
1068         if (!*name)
1069                 return alloc_delete_ref();
1070         if (get_sha1(name, sha1))
1071                 return NULL;
1072         ref = alloc_ref(name);
1073         hashcpy(ref->new_sha1, sha1);
1074         return ref;
1075 }
1076
1077 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1078 {
1079         struct ref *ret = alloc_ref(name);
1080         tail_link_ref(ret, tail);
1081         return ret;
1082 }
1083
1084 static char *guess_ref(const char *name, struct ref *peer)
1085 {
1086         struct strbuf buf = STRBUF_INIT;
1087         unsigned char sha1[20];
1088
1089         const char *r = resolve_ref_unsafe(peer->name, sha1, 1, NULL);
1090         if (!r)
1091                 return NULL;
1092
1093         if (starts_with(r, "refs/heads/"))
1094                 strbuf_addstr(&buf, "refs/heads/");
1095         else if (starts_with(r, "refs/tags/"))
1096                 strbuf_addstr(&buf, "refs/tags/");
1097         else
1098                 return NULL;
1099
1100         strbuf_addstr(&buf, name);
1101         return strbuf_detach(&buf, NULL);
1102 }
1103
1104 static int match_explicit(struct ref *src, struct ref *dst,
1105                           struct ref ***dst_tail,
1106                           struct refspec *rs)
1107 {
1108         struct ref *matched_src, *matched_dst;
1109         int copy_src;
1110
1111         const char *dst_value = rs->dst;
1112         char *dst_guess;
1113
1114         if (rs->pattern || rs->matching)
1115                 return 0;
1116
1117         matched_src = matched_dst = NULL;
1118         switch (count_refspec_match(rs->src, src, &matched_src)) {
1119         case 1:
1120                 copy_src = 1;
1121                 break;
1122         case 0:
1123                 /* The source could be in the get_sha1() format
1124                  * not a reference name.  :refs/other is a
1125                  * way to delete 'other' ref at the remote end.
1126                  */
1127                 matched_src = try_explicit_object_name(rs->src);
1128                 if (!matched_src)
1129                         return error("src refspec %s does not match any.", rs->src);
1130                 copy_src = 0;
1131                 break;
1132         default:
1133                 return error("src refspec %s matches more than one.", rs->src);
1134         }
1135
1136         if (!dst_value) {
1137                 unsigned char sha1[20];
1138                 int flag;
1139
1140                 dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
1141                 if (!dst_value ||
1142                     ((flag & REF_ISSYMREF) &&
1143                      !starts_with(dst_value, "refs/heads/")))
1144                         die("%s cannot be resolved to branch.",
1145                             matched_src->name);
1146         }
1147
1148         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1149         case 1:
1150                 break;
1151         case 0:
1152                 if (!memcmp(dst_value, "refs/", 5))
1153                         matched_dst = make_linked_ref(dst_value, dst_tail);
1154                 else if (is_null_sha1(matched_src->new_sha1))
1155                         error("unable to delete '%s': remote ref does not exist",
1156                               dst_value);
1157                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1158                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1159                 else
1160                         error("unable to push to unqualified destination: %s\n"
1161                               "The destination refspec neither matches an "
1162                               "existing ref on the remote nor\n"
1163                               "begins with refs/, and we are unable to "
1164                               "guess a prefix based on the source ref.",
1165                               dst_value);
1166                 break;
1167         default:
1168                 matched_dst = NULL;
1169                 error("dst refspec %s matches more than one.",
1170                       dst_value);
1171                 break;
1172         }
1173         if (!matched_dst)
1174                 return -1;
1175         if (matched_dst->peer_ref)
1176                 return error("dst ref %s receives from more than one src.",
1177                       matched_dst->name);
1178         else {
1179                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1180                 matched_dst->force = rs->force;
1181         }
1182         return 0;
1183 }
1184
1185 static int match_explicit_refs(struct ref *src, struct ref *dst,
1186                                struct ref ***dst_tail, struct refspec *rs,
1187                                int rs_nr)
1188 {
1189         int i, errs;
1190         for (i = errs = 0; i < rs_nr; i++)
1191                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1192         return errs;
1193 }
1194
1195 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1196                 int send_mirror, int direction, const struct refspec **ret_pat)
1197 {
1198         const struct refspec *pat;
1199         char *name;
1200         int i;
1201         int matching_refs = -1;
1202         for (i = 0; i < rs_nr; i++) {
1203                 if (rs[i].matching &&
1204                     (matching_refs == -1 || rs[i].force)) {
1205                         matching_refs = i;
1206                         continue;
1207                 }
1208
1209                 if (rs[i].pattern) {
1210                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1211                         int match;
1212                         if (direction == FROM_SRC)
1213                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1214                         else
1215                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1216                         if (match) {
1217                                 matching_refs = i;
1218                                 break;
1219                         }
1220                 }
1221         }
1222         if (matching_refs == -1)
1223                 return NULL;
1224
1225         pat = rs + matching_refs;
1226         if (pat->matching) {
1227                 /*
1228                  * "matching refs"; traditionally we pushed everything
1229                  * including refs outside refs/heads/ hierarchy, but
1230                  * that does not make much sense these days.
1231                  */
1232                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1233                         return NULL;
1234                 name = xstrdup(ref->name);
1235         }
1236         if (ret_pat)
1237                 *ret_pat = pat;
1238         return name;
1239 }
1240
1241 static struct ref **tail_ref(struct ref **head)
1242 {
1243         struct ref **tail = head;
1244         while (*tail)
1245                 tail = &((*tail)->next);
1246         return tail;
1247 }
1248
1249 struct tips {
1250         struct commit **tip;
1251         int nr, alloc;
1252 };
1253
1254 static void add_to_tips(struct tips *tips, const unsigned char *sha1)
1255 {
1256         struct commit *commit;
1257
1258         if (is_null_sha1(sha1))
1259                 return;
1260         commit = lookup_commit_reference_gently(sha1, 1);
1261         if (!commit || (commit->object.flags & TMP_MARK))
1262                 return;
1263         commit->object.flags |= TMP_MARK;
1264         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1265         tips->tip[tips->nr++] = commit;
1266 }
1267
1268 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1269 {
1270         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1271         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1272         struct string_list_item *item;
1273         struct ref *ref;
1274         struct tips sent_tips;
1275
1276         /*
1277          * Collect everything we know they would have at the end of
1278          * this push, and collect all tags they have.
1279          */
1280         memset(&sent_tips, 0, sizeof(sent_tips));
1281         for (ref = *dst; ref; ref = ref->next) {
1282                 if (ref->peer_ref &&
1283                     !is_null_sha1(ref->peer_ref->new_sha1))
1284                         add_to_tips(&sent_tips, ref->peer_ref->new_sha1);
1285                 else
1286                         add_to_tips(&sent_tips, ref->old_sha1);
1287                 if (starts_with(ref->name, "refs/tags/"))
1288                         string_list_append(&dst_tag, ref->name);
1289         }
1290         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1291
1292         sort_string_list(&dst_tag);
1293
1294         /* Collect tags they do not have. */
1295         for (ref = src; ref; ref = ref->next) {
1296                 if (!starts_with(ref->name, "refs/tags/"))
1297                         continue; /* not a tag */
1298                 if (string_list_has_string(&dst_tag, ref->name))
1299                         continue; /* they already have it */
1300                 if (sha1_object_info(ref->new_sha1, NULL) != OBJ_TAG)
1301                         continue; /* be conservative */
1302                 item = string_list_append(&src_tag, ref->name);
1303                 item->util = ref;
1304         }
1305         string_list_clear(&dst_tag, 0);
1306
1307         /*
1308          * At this point, src_tag lists tags that are missing from
1309          * dst, and sent_tips lists the tips we are pushing or those
1310          * that we know they already have. An element in the src_tag
1311          * that is an ancestor of any of the sent_tips needs to be
1312          * sent to the other side.
1313          */
1314         if (sent_tips.nr) {
1315                 for_each_string_list_item(item, &src_tag) {
1316                         struct ref *ref = item->util;
1317                         struct ref *dst_ref;
1318                         struct commit *commit;
1319
1320                         if (is_null_sha1(ref->new_sha1))
1321                                 continue;
1322                         commit = lookup_commit_reference_gently(ref->new_sha1, 1);
1323                         if (!commit)
1324                                 /* not pushing a commit, which is not an error */
1325                                 continue;
1326
1327                         /*
1328                          * Is this tag, which they do not have, reachable from
1329                          * any of the commits we are sending?
1330                          */
1331                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1332                                 continue;
1333
1334                         /* Add it in */
1335                         dst_ref = make_linked_ref(ref->name, dst_tail);
1336                         hashcpy(dst_ref->new_sha1, ref->new_sha1);
1337                         dst_ref->peer_ref = copy_ref(ref);
1338                 }
1339         }
1340         string_list_clear(&src_tag, 0);
1341         free(sent_tips.tip);
1342 }
1343
1344 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1345 {
1346         for ( ; list; list = list->next)
1347                 if (!strcmp(list->name, name))
1348                         return (struct ref *)list;
1349         return NULL;
1350 }
1351
1352 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1353 {
1354         for ( ; ref; ref = ref->next)
1355                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1356
1357         sort_string_list(ref_index);
1358 }
1359
1360 /*
1361  * Given the set of refs the local repository has, the set of refs the
1362  * remote repository has, and the refspec used for push, determine
1363  * what remote refs we will update and with what value by setting
1364  * peer_ref (which object is being pushed) and force (if the push is
1365  * forced) in elements of "dst". The function may add new elements to
1366  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1367  */
1368 int match_push_refs(struct ref *src, struct ref **dst,
1369                     int nr_refspec, const char **refspec, int flags)
1370 {
1371         struct refspec *rs;
1372         int send_all = flags & MATCH_REFS_ALL;
1373         int send_mirror = flags & MATCH_REFS_MIRROR;
1374         int send_prune = flags & MATCH_REFS_PRUNE;
1375         int errs;
1376         static const char *default_refspec[] = { ":", NULL };
1377         struct ref *ref, **dst_tail = tail_ref(dst);
1378         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1379
1380         if (!nr_refspec) {
1381                 nr_refspec = 1;
1382                 refspec = default_refspec;
1383         }
1384         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1385         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1386
1387         /* pick the remainder */
1388         for (ref = src; ref; ref = ref->next) {
1389                 struct string_list_item *dst_item;
1390                 struct ref *dst_peer;
1391                 const struct refspec *pat = NULL;
1392                 char *dst_name;
1393
1394                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1395                 if (!dst_name)
1396                         continue;
1397
1398                 if (!dst_ref_index.nr)
1399                         prepare_ref_index(&dst_ref_index, *dst);
1400
1401                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1402                 dst_peer = dst_item ? dst_item->util : NULL;
1403                 if (dst_peer) {
1404                         if (dst_peer->peer_ref)
1405                                 /* We're already sending something to this ref. */
1406                                 goto free_name;
1407                 } else {
1408                         if (pat->matching && !(send_all || send_mirror))
1409                                 /*
1410                                  * Remote doesn't have it, and we have no
1411                                  * explicit pattern, and we don't have
1412                                  * --all nor --mirror.
1413                                  */
1414                                 goto free_name;
1415
1416                         /* Create a new one and link it */
1417                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1418                         hashcpy(dst_peer->new_sha1, ref->new_sha1);
1419                         string_list_insert(&dst_ref_index,
1420                                 dst_peer->name)->util = dst_peer;
1421                 }
1422                 dst_peer->peer_ref = copy_ref(ref);
1423                 dst_peer->force = pat->force;
1424         free_name:
1425                 free(dst_name);
1426         }
1427
1428         string_list_clear(&dst_ref_index, 0);
1429
1430         if (flags & MATCH_REFS_FOLLOW_TAGS)
1431                 add_missing_tags(src, dst, &dst_tail);
1432
1433         if (send_prune) {
1434                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1435                 /* check for missing refs on the remote */
1436                 for (ref = *dst; ref; ref = ref->next) {
1437                         char *src_name;
1438
1439                         if (ref->peer_ref)
1440                                 /* We're already sending something to this ref. */
1441                                 continue;
1442
1443                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1444                         if (src_name) {
1445                                 if (!src_ref_index.nr)
1446                                         prepare_ref_index(&src_ref_index, src);
1447                                 if (!string_list_has_string(&src_ref_index,
1448                                             src_name))
1449                                         ref->peer_ref = alloc_delete_ref();
1450                                 free(src_name);
1451                         }
1452                 }
1453                 string_list_clear(&src_ref_index, 0);
1454         }
1455         if (errs)
1456                 return -1;
1457         return 0;
1458 }
1459
1460 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1461                              int force_update)
1462 {
1463         struct ref *ref;
1464
1465         for (ref = remote_refs; ref; ref = ref->next) {
1466                 int force_ref_update = ref->force || force_update;
1467                 int reject_reason = 0;
1468
1469                 if (ref->peer_ref)
1470                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1471                 else if (!send_mirror)
1472                         continue;
1473
1474                 ref->deletion = is_null_sha1(ref->new_sha1);
1475                 if (!ref->deletion &&
1476                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1477                         ref->status = REF_STATUS_UPTODATE;
1478                         continue;
1479                 }
1480
1481                 /*
1482                  * Bypass the usual "must fast-forward" check but
1483                  * replace it with a weaker "the old value must be
1484                  * this value we observed".  If the remote ref has
1485                  * moved and is now different from what we expect,
1486                  * reject any push.
1487                  *
1488                  * It also is an error if the user told us to check
1489                  * with the remote-tracking branch to find the value
1490                  * to expect, but we did not have such a tracking
1491                  * branch.
1492                  */
1493                 if (ref->expect_old_sha1) {
1494                         if (ref->expect_old_no_trackback ||
1495                             hashcmp(ref->old_sha1, ref->old_sha1_expect))
1496                                 reject_reason = REF_STATUS_REJECT_STALE;
1497                 }
1498
1499                 /*
1500                  * The usual "must fast-forward" rules.
1501                  *
1502                  * Decide whether an individual refspec A:B can be
1503                  * pushed.  The push will succeed if any of the
1504                  * following are true:
1505                  *
1506                  * (1) the remote reference B does not exist
1507                  *
1508                  * (2) the remote reference B is being removed (i.e.,
1509                  *     pushing :B where no source is specified)
1510                  *
1511                  * (3) the destination is not under refs/tags/, and
1512                  *     if the old and new value is a commit, the new
1513                  *     is a descendant of the old.
1514                  *
1515                  * (4) it is forced using the +A:B notation, or by
1516                  *     passing the --force argument
1517                  */
1518
1519                 else if (!ref->deletion && !is_null_sha1(ref->old_sha1)) {
1520                         if (starts_with(ref->name, "refs/tags/"))
1521                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1522                         else if (!has_sha1_file(ref->old_sha1))
1523                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1524                         else if (!lookup_commit_reference_gently(ref->old_sha1, 1) ||
1525                                  !lookup_commit_reference_gently(ref->new_sha1, 1))
1526                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1527                         else if (!ref_newer(ref->new_sha1, ref->old_sha1))
1528                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1529                 }
1530
1531                 /*
1532                  * "--force" will defeat any rejection implemented
1533                  * by the rules above.
1534                  */
1535                 if (!force_ref_update)
1536                         ref->status = reject_reason;
1537                 else if (reject_reason)
1538                         ref->forced_update = 1;
1539         }
1540 }
1541
1542 struct branch *branch_get(const char *name)
1543 {
1544         struct branch *ret;
1545
1546         read_config();
1547         if (!name || !*name || !strcmp(name, "HEAD"))
1548                 ret = current_branch;
1549         else
1550                 ret = make_branch(name, 0);
1551         if (ret && ret->remote_name) {
1552                 ret->remote = remote_get(ret->remote_name);
1553                 if (ret->merge_nr) {
1554                         int i;
1555                         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1556                         for (i = 0; i < ret->merge_nr; i++) {
1557                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1558                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1559                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1560                                     && !strcmp(ret->remote_name, "."))
1561                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1562                         }
1563                 }
1564         }
1565         return ret;
1566 }
1567
1568 int branch_has_merge_config(struct branch *branch)
1569 {
1570         return branch && !!branch->merge;
1571 }
1572
1573 int branch_merge_matches(struct branch *branch,
1574                                  int i,
1575                                  const char *refname)
1576 {
1577         if (!branch || i < 0 || i >= branch->merge_nr)
1578                 return 0;
1579         return refname_match(branch->merge[i]->src, refname);
1580 }
1581
1582 static int ignore_symref_update(const char *refname)
1583 {
1584         unsigned char sha1[20];
1585         int flag;
1586
1587         if (!resolve_ref_unsafe(refname, sha1, 0, &flag))
1588                 return 0; /* non-existing refs are OK */
1589         return (flag & REF_ISSYMREF);
1590 }
1591
1592 /*
1593  * Create and return a list of (struct ref) consisting of copies of
1594  * each remote_ref that matches refspec.  refspec must be a pattern.
1595  * Fill in the copies' peer_ref to describe the local tracking refs to
1596  * which they map.  Omit any references that would map to an existing
1597  * local symbolic ref.
1598  */
1599 static struct ref *get_expanded_map(const struct ref *remote_refs,
1600                                     const struct refspec *refspec)
1601 {
1602         const struct ref *ref;
1603         struct ref *ret = NULL;
1604         struct ref **tail = &ret;
1605
1606         for (ref = remote_refs; ref; ref = ref->next) {
1607                 char *expn_name = NULL;
1608
1609                 if (strchr(ref->name, '^'))
1610                         continue; /* a dereference item */
1611                 if (match_name_with_pattern(refspec->src, ref->name,
1612                                             refspec->dst, &expn_name) &&
1613                     !ignore_symref_update(expn_name)) {
1614                         struct ref *cpy = copy_ref(ref);
1615
1616                         cpy->peer_ref = alloc_ref(expn_name);
1617                         if (refspec->force)
1618                                 cpy->peer_ref->force = 1;
1619                         *tail = cpy;
1620                         tail = &cpy->next;
1621                 }
1622                 free(expn_name);
1623         }
1624
1625         return ret;
1626 }
1627
1628 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1629 {
1630         const struct ref *ref;
1631         for (ref = refs; ref; ref = ref->next) {
1632                 if (refname_match(name, ref->name))
1633                         return ref;
1634         }
1635         return NULL;
1636 }
1637
1638 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1639 {
1640         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1641
1642         if (!ref)
1643                 return NULL;
1644
1645         return copy_ref(ref);
1646 }
1647
1648 static struct ref *get_local_ref(const char *name)
1649 {
1650         if (!name || name[0] == '\0')
1651                 return NULL;
1652
1653         if (starts_with(name, "refs/"))
1654                 return alloc_ref(name);
1655
1656         if (starts_with(name, "heads/") ||
1657             starts_with(name, "tags/") ||
1658             starts_with(name, "remotes/"))
1659                 return alloc_ref_with_prefix("refs/", 5, name);
1660
1661         return alloc_ref_with_prefix("refs/heads/", 11, name);
1662 }
1663
1664 int get_fetch_map(const struct ref *remote_refs,
1665                   const struct refspec *refspec,
1666                   struct ref ***tail,
1667                   int missing_ok)
1668 {
1669         struct ref *ref_map, **rmp;
1670
1671         if (refspec->pattern) {
1672                 ref_map = get_expanded_map(remote_refs, refspec);
1673         } else {
1674                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1675
1676                 if (refspec->exact_sha1) {
1677                         ref_map = alloc_ref(name);
1678                         get_sha1_hex(name, ref_map->old_sha1);
1679                 } else {
1680                         ref_map = get_remote_ref(remote_refs, name);
1681                 }
1682                 if (!missing_ok && !ref_map)
1683                         die("Couldn't find remote ref %s", name);
1684                 if (ref_map) {
1685                         ref_map->peer_ref = get_local_ref(refspec->dst);
1686                         if (ref_map->peer_ref && refspec->force)
1687                                 ref_map->peer_ref->force = 1;
1688                 }
1689         }
1690
1691         for (rmp = &ref_map; *rmp; ) {
1692                 if ((*rmp)->peer_ref) {
1693                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1694                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1695                                 struct ref *ignore = *rmp;
1696                                 error("* Ignoring funny ref '%s' locally",
1697                                       (*rmp)->peer_ref->name);
1698                                 *rmp = (*rmp)->next;
1699                                 free(ignore->peer_ref);
1700                                 free(ignore);
1701                                 continue;
1702                         }
1703                 }
1704                 rmp = &((*rmp)->next);
1705         }
1706
1707         if (ref_map)
1708                 tail_link_ref(ref_map, tail);
1709
1710         return 0;
1711 }
1712
1713 int resolve_remote_symref(struct ref *ref, struct ref *list)
1714 {
1715         if (!ref->symref)
1716                 return 0;
1717         for (; list; list = list->next)
1718                 if (!strcmp(ref->symref, list->name)) {
1719                         hashcpy(ref->old_sha1, list->old_sha1);
1720                         return 0;
1721                 }
1722         return 1;
1723 }
1724
1725 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1726 {
1727         while (list) {
1728                 struct commit_list *temp = list;
1729                 temp->item->object.flags &= ~mark;
1730                 list = temp->next;
1731                 free(temp);
1732         }
1733 }
1734
1735 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1736 {
1737         struct object *o;
1738         struct commit *old, *new;
1739         struct commit_list *list, *used;
1740         int found = 0;
1741
1742         /*
1743          * Both new and old must be commit-ish and new is descendant of
1744          * old.  Otherwise we require --force.
1745          */
1746         o = deref_tag(parse_object(old_sha1), NULL, 0);
1747         if (!o || o->type != OBJ_COMMIT)
1748                 return 0;
1749         old = (struct commit *) o;
1750
1751         o = deref_tag(parse_object(new_sha1), NULL, 0);
1752         if (!o || o->type != OBJ_COMMIT)
1753                 return 0;
1754         new = (struct commit *) o;
1755
1756         if (parse_commit(new) < 0)
1757                 return 0;
1758
1759         used = list = NULL;
1760         commit_list_insert(new, &list);
1761         while (list) {
1762                 new = pop_most_recent_commit(&list, TMP_MARK);
1763                 commit_list_insert(new, &used);
1764                 if (new == old) {
1765                         found = 1;
1766                         break;
1767                 }
1768         }
1769         unmark_and_free(list, TMP_MARK);
1770         unmark_and_free(used, TMP_MARK);
1771         return found;
1772 }
1773
1774 /*
1775  * Compare a branch with its upstream, and save their differences (number
1776  * of commits) in *num_ours and *num_theirs.
1777  *
1778  * Return 0 if branch has no upstream (no base), -1 if upstream is missing
1779  * (with "gone" base), otherwise 1 (with base).
1780  */
1781 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1782 {
1783         unsigned char sha1[20];
1784         struct commit *ours, *theirs;
1785         char symmetric[84];
1786         struct rev_info revs;
1787         const char *rev_argv[10], *base;
1788         int rev_argc;
1789
1790         /* Cannot stat unless we are marked to build on top of somebody else. */
1791         if (!branch ||
1792             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1793                 return 0;
1794
1795         /* Cannot stat if what we used to build on no longer exists */
1796         base = branch->merge[0]->dst;
1797         if (read_ref(base, sha1))
1798                 return -1;
1799         theirs = lookup_commit_reference(sha1);
1800         if (!theirs)
1801                 return -1;
1802
1803         if (read_ref(branch->refname, sha1))
1804                 return -1;
1805         ours = lookup_commit_reference(sha1);
1806         if (!ours)
1807                 return -1;
1808
1809         /* are we the same? */
1810         if (theirs == ours) {
1811                 *num_theirs = *num_ours = 0;
1812                 return 1;
1813         }
1814
1815         /* Run "rev-list --left-right ours...theirs" internally... */
1816         rev_argc = 0;
1817         rev_argv[rev_argc++] = NULL;
1818         rev_argv[rev_argc++] = "--left-right";
1819         rev_argv[rev_argc++] = symmetric;
1820         rev_argv[rev_argc++] = "--";
1821         rev_argv[rev_argc] = NULL;
1822
1823         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1824         strcpy(symmetric + 40, "...");
1825         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1826
1827         init_revisions(&revs, NULL);
1828         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1829         prepare_revision_walk(&revs);
1830
1831         /* ... and count the commits on each side. */
1832         *num_ours = 0;
1833         *num_theirs = 0;
1834         while (1) {
1835                 struct commit *c = get_revision(&revs);
1836                 if (!c)
1837                         break;
1838                 if (c->object.flags & SYMMETRIC_LEFT)
1839                         (*num_ours)++;
1840                 else
1841                         (*num_theirs)++;
1842         }
1843
1844         /* clear object flags smudged by the above traversal */
1845         clear_commit_marks(ours, ALL_REV_FLAGS);
1846         clear_commit_marks(theirs, ALL_REV_FLAGS);
1847         return 1;
1848 }
1849
1850 /*
1851  * Return true when there is anything to report, otherwise false.
1852  */
1853 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1854 {
1855         int ours, theirs;
1856         const char *base;
1857         int upstream_is_gone = 0;
1858
1859         switch (stat_tracking_info(branch, &ours, &theirs)) {
1860         case 0:
1861                 /* no base */
1862                 return 0;
1863         case -1:
1864                 /* with "gone" base */
1865                 upstream_is_gone = 1;
1866                 break;
1867         default:
1868                 /* with base */
1869                 break;
1870         }
1871
1872         base = branch->merge[0]->dst;
1873         base = shorten_unambiguous_ref(base, 0);
1874         if (upstream_is_gone) {
1875                 strbuf_addf(sb,
1876                         _("Your branch is based on '%s', but the upstream is gone.\n"),
1877                         base);
1878                 if (advice_status_hints)
1879                         strbuf_addf(sb,
1880                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
1881         } else if (!ours && !theirs) {
1882                 strbuf_addf(sb,
1883                         _("Your branch is up-to-date with '%s'.\n"),
1884                         base);
1885         } else if (!theirs) {
1886                 strbuf_addf(sb,
1887                         Q_("Your branch is ahead of '%s' by %d commit.\n",
1888                            "Your branch is ahead of '%s' by %d commits.\n",
1889                            ours),
1890                         base, ours);
1891                 if (advice_status_hints)
1892                         strbuf_addf(sb,
1893                                 _("  (use \"git push\" to publish your local commits)\n"));
1894         } else if (!ours) {
1895                 strbuf_addf(sb,
1896                         Q_("Your branch is behind '%s' by %d commit, "
1897                                "and can be fast-forwarded.\n",
1898                            "Your branch is behind '%s' by %d commits, "
1899                                "and can be fast-forwarded.\n",
1900                            theirs),
1901                         base, theirs);
1902                 if (advice_status_hints)
1903                         strbuf_addf(sb,
1904                                 _("  (use \"git pull\" to update your local branch)\n"));
1905         } else {
1906                 strbuf_addf(sb,
1907                         Q_("Your branch and '%s' have diverged,\n"
1908                                "and have %d and %d different commit each, "
1909                                "respectively.\n",
1910                            "Your branch and '%s' have diverged,\n"
1911                                "and have %d and %d different commits each, "
1912                                "respectively.\n",
1913                            theirs),
1914                         base, ours, theirs);
1915                 if (advice_status_hints)
1916                         strbuf_addf(sb,
1917                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
1918         }
1919         return 1;
1920 }
1921
1922 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1923 {
1924         struct ref ***local_tail = cb_data;
1925         struct ref *ref;
1926         int len;
1927
1928         /* we already know it starts with refs/ to get here */
1929         if (check_refname_format(refname + 5, 0))
1930                 return 0;
1931
1932         len = strlen(refname) + 1;
1933         ref = xcalloc(1, sizeof(*ref) + len);
1934         hashcpy(ref->new_sha1, sha1);
1935         memcpy(ref->name, refname, len);
1936         **local_tail = ref;
1937         *local_tail = &ref->next;
1938         return 0;
1939 }
1940
1941 struct ref *get_local_heads(void)
1942 {
1943         struct ref *local_refs = NULL, **local_tail = &local_refs;
1944         for_each_ref(one_local_ref, &local_tail);
1945         return local_refs;
1946 }
1947
1948 struct ref *guess_remote_head(const struct ref *head,
1949                               const struct ref *refs,
1950                               int all)
1951 {
1952         const struct ref *r;
1953         struct ref *list = NULL;
1954         struct ref **tail = &list;
1955
1956         if (!head)
1957                 return NULL;
1958
1959         /*
1960          * Some transports support directly peeking at
1961          * where HEAD points; if that is the case, then
1962          * we don't have to guess.
1963          */
1964         if (head->symref)
1965                 return copy_ref(find_ref_by_name(refs, head->symref));
1966
1967         /* If refs/heads/master could be right, it is. */
1968         if (!all) {
1969                 r = find_ref_by_name(refs, "refs/heads/master");
1970                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1971                         return copy_ref(r);
1972         }
1973
1974         /* Look for another ref that points there */
1975         for (r = refs; r; r = r->next) {
1976                 if (r != head &&
1977                     starts_with(r->name, "refs/heads/") &&
1978                     !hashcmp(r->old_sha1, head->old_sha1)) {
1979                         *tail = copy_ref(r);
1980                         tail = &((*tail)->next);
1981                         if (!all)
1982                                 break;
1983                 }
1984         }
1985
1986         return list;
1987 }
1988
1989 struct stale_heads_info {
1990         struct string_list *ref_names;
1991         struct ref **stale_refs_tail;
1992         struct refspec *refs;
1993         int ref_count;
1994 };
1995
1996 static int get_stale_heads_cb(const char *refname,
1997         const unsigned char *sha1, int flags, void *cb_data)
1998 {
1999         struct stale_heads_info *info = cb_data;
2000         struct refspec query;
2001         memset(&query, 0, sizeof(struct refspec));
2002         query.dst = (char *)refname;
2003
2004         if (query_refspecs(info->refs, info->ref_count, &query))
2005                 return 0; /* No matches */
2006
2007         /*
2008          * If we did find a suitable refspec and it's not a symref and
2009          * it's not in the list of refs that currently exist in that
2010          * remote we consider it to be stale.
2011          */
2012         if (!((flags & REF_ISSYMREF) ||
2013               string_list_has_string(info->ref_names, query.src))) {
2014                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2015                 hashcpy(ref->new_sha1, sha1);
2016         }
2017
2018         free(query.src);
2019         return 0;
2020 }
2021
2022 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
2023 {
2024         struct ref *ref, *stale_refs = NULL;
2025         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2026         struct stale_heads_info info;
2027         info.ref_names = &ref_names;
2028         info.stale_refs_tail = &stale_refs;
2029         info.refs = refs;
2030         info.ref_count = ref_count;
2031         for (ref = fetch_map; ref; ref = ref->next)
2032                 string_list_append(&ref_names, ref->name);
2033         sort_string_list(&ref_names);
2034         for_each_ref(get_stale_heads_cb, &info);
2035         string_list_clear(&ref_names, 0);
2036         return stale_refs;
2037 }
2038
2039 /*
2040  * Compare-and-swap
2041  */
2042 void clear_cas_option(struct push_cas_option *cas)
2043 {
2044         int i;
2045
2046         for (i = 0; i < cas->nr; i++)
2047                 free(cas->entry[i].refname);
2048         free(cas->entry);
2049         memset(cas, 0, sizeof(*cas));
2050 }
2051
2052 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2053                                       const char *refname,
2054                                       size_t refnamelen)
2055 {
2056         struct push_cas *entry;
2057         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2058         entry = &cas->entry[cas->nr++];
2059         memset(entry, 0, sizeof(*entry));
2060         entry->refname = xmemdupz(refname, refnamelen);
2061         return entry;
2062 }
2063
2064 int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2065 {
2066         const char *colon;
2067         struct push_cas *entry;
2068
2069         if (unset) {
2070                 /* "--no-<option>" */
2071                 clear_cas_option(cas);
2072                 return 0;
2073         }
2074
2075         if (!arg) {
2076                 /* just "--<option>" */
2077                 cas->use_tracking_for_rest = 1;
2078                 return 0;
2079         }
2080
2081         /* "--<option>=refname" or "--<option>=refname:value" */
2082         colon = strchrnul(arg, ':');
2083         entry = add_cas_entry(cas, arg, colon - arg);
2084         if (!*colon)
2085                 entry->use_tracking = 1;
2086         else if (get_sha1(colon + 1, entry->expect))
2087                 return error("cannot parse expected object name '%s'", colon + 1);
2088         return 0;
2089 }
2090
2091 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2092 {
2093         return parse_push_cas_option(opt->value, arg, unset);
2094 }
2095
2096 int is_empty_cas(const struct push_cas_option *cas)
2097 {
2098         return !cas->use_tracking_for_rest && !cas->nr;
2099 }
2100
2101 /*
2102  * Look at remote.fetch refspec and see if we have a remote
2103  * tracking branch for the refname there.  Fill its current
2104  * value in sha1[].
2105  * If we cannot do so, return negative to signal an error.
2106  */
2107 static int remote_tracking(struct remote *remote, const char *refname,
2108                            unsigned char sha1[20])
2109 {
2110         char *dst;
2111
2112         dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
2113         if (!dst)
2114                 return -1; /* no tracking ref for refname at remote */
2115         if (read_ref(dst, sha1))
2116                 return -1; /* we know what the tracking ref is but we cannot read it */
2117         return 0;
2118 }
2119
2120 static void apply_cas(struct push_cas_option *cas,
2121                       struct remote *remote,
2122                       struct ref *ref)
2123 {
2124         int i;
2125
2126         /* Find an explicit --<option>=<name>[:<value>] entry */
2127         for (i = 0; i < cas->nr; i++) {
2128                 struct push_cas *entry = &cas->entry[i];
2129                 if (!refname_match(entry->refname, ref->name))
2130                         continue;
2131                 ref->expect_old_sha1 = 1;
2132                 if (!entry->use_tracking)
2133                         hashcpy(ref->old_sha1_expect, cas->entry[i].expect);
2134                 else if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2135                         ref->expect_old_no_trackback = 1;
2136                 return;
2137         }
2138
2139         /* Are we using "--<option>" to cover all? */
2140         if (!cas->use_tracking_for_rest)
2141                 return;
2142
2143         ref->expect_old_sha1 = 1;
2144         if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2145                 ref->expect_old_no_trackback = 1;
2146 }
2147
2148 void apply_push_cas(struct push_cas_option *cas,
2149                     struct remote *remote,
2150                     struct ref *remote_refs)
2151 {
2152         struct ref *ref;
2153         for (ref = remote_refs; ref; ref = ref->next)
2154                 apply_cas(cas, remote, ref);
2155 }