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 *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 static void query_refspecs_multiple(struct refspec *refs, int ref_count, struct refspec *query, struct string_list *results)
 861 {
 862         int i;
 863         int find_src = !query->src;
 864
 865         if (find_src && !query->dst)
 866                 error("query_refspecs_multiple: need either src or dst");
 867
 868         for (i = 0; i < ref_count; i++) {
 869                 struct refspec *refspec = &refs[i];
 870                 const char *key = find_src ? refspec->dst : refspec->src;
 871                 const char *value = find_src ? refspec->src : refspec->dst;
 872                 const char *needle = find_src ? query->dst : query->src;
 873                 char **result = find_src ? &query->src : &query->dst;
 874
 875                 if (!refspec->dst)
 876                         continue;
 877                 if (refspec->pattern) {
 878                         if (match_name_with_pattern(key, needle, value, result))
 879                                 string_list_append_nodup(results, *result);
 880                 } else if (!strcmp(needle, key)) {
 881                         string_list_append(results, value);
 882                 }
 883         }
 884 }
 885
 886 int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
 887 {
 888         int i;
 889         int find_src = !query->src;
 890         const char *needle = find_src ? query->dst : query->src;
 891         char **result = find_src ? &query->src : &query->dst;
 892
 893         if (find_src && !query->dst)
 894                 return error("query_refspecs: need either src or dst");
 895
 896         for (i = 0; i < ref_count; i++) {
 897                 struct refspec *refspec = &refs[i];
 898                 const char *key = find_src ? refspec->dst : refspec->src;
 899                 const char *value = find_src ? refspec->src : refspec->dst;
 900
 901                 if (!refspec->dst)
 902                         continue;
 903                 if (refspec->pattern) {
 904                         if (match_name_with_pattern(key, needle, value, result)) {
 905                                 query->force = refspec->force;
 906                                 return 0;
 907                         }
 908                 } else if (!strcmp(needle, key)) {
 909                         *result = xstrdup(value);
 910                         query->force = refspec->force;
 911                         return 0;
 912                 }
 913         }
 914         return -1;
 915 }
 916
 917 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 918                      const char *name)
 919 {
 920         struct refspec query;
 921
 922         memset(&query, 0, sizeof(struct refspec));
 923         query.src = (char *)name;
 924
 925         if (query_refspecs(refspecs, nr_refspec, &query))
 926                 return NULL;
 927
 928         return query.dst;
 929 }
 930
 931 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 932 {
 933         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
 934 }
 935
 936 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 937                 const char *name)
 938 {
 939         size_t len = strlen(name);
 940         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 941         memcpy(ref->name, prefix, prefixlen);
 942         memcpy(ref->name + prefixlen, name, len);
 943         return ref;
 944 }
 945
 946 struct ref *alloc_ref(const char *name)
 947 {
 948         return alloc_ref_with_prefix("", 0, name);
 949 }
 950
 951 struct ref *copy_ref(const struct ref *ref)
 952 {
 953         struct ref *cpy;
 954         size_t len;
 955         if (!ref)
 956                 return NULL;
 957         len = strlen(ref->name);
 958         cpy = xmalloc(sizeof(struct ref) + len + 1);
 959         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 960         cpy->next = NULL;
 961         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 962         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 963         cpy->peer_ref = copy_ref(ref->peer_ref);
 964         return cpy;
 965 }
 966
 967 struct ref *copy_ref_list(const struct ref *ref)
 968 {
 969         struct ref *ret = NULL;
 970         struct ref **tail = &ret;
 971         while (ref) {
 972                 *tail = copy_ref(ref);
 973                 ref = ref->next;
 974                 tail = &((*tail)->next);
 975         }
 976         return ret;
 977 }
 978
 979 static void free_ref(struct ref *ref)
 980 {
 981         if (!ref)
 982                 return;
 983         free_ref(ref->peer_ref);
 984         free(ref->remote_status);
 985         free(ref->symref);
 986         free(ref);
 987 }
 988
 989 void free_refs(struct ref *ref)
 990 {
 991         struct ref *next;
 992         while (ref) {
 993                 next = ref->next;
 994                 free_ref(ref);
 995                 ref = next;
 996         }
 997 }
 998
 999 int ref_compare_name(const void *va, const void *vb)
1000 {
1001         const struct ref *a = va, *b = vb;
1002         return strcmp(a->name, b->name);
1003 }
1004
1005 static void *ref_list_get_next(const void *a)
1006 {
1007         return ((const struct ref *)a)->next;
1008 }
1009
1010 static void ref_list_set_next(void *a, void *next)
1011 {
1012         ((struct ref *)a)->next = next;
1013 }
1014
1015 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
1016 {
1017         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
1018 }
1019
1020 int count_refspec_match(const char *pattern,
1021                         struct ref *refs,
1022                         struct ref **matched_ref)
1023 {
1024         int patlen = strlen(pattern);
1025         struct ref *matched_weak = NULL;
1026         struct ref *matched = NULL;
1027         int weak_match = 0;
1028         int match = 0;
1029
1030         for (weak_match = match = 0; refs; refs = refs->next) {
1031                 char *name = refs->name;
1032                 int namelen = strlen(name);
1033
1034                 if (!refname_match(pattern, name))
1035                         continue;
1036
1037                 /* A match is "weak" if it is with refs outside
1038                  * heads or tags, and did not specify the pattern
1039                  * in full (e.g. "refs/remotes/origin/master") or at
1040                  * least from the toplevel (e.g. "remotes/origin/master");
1041                  * otherwise "git push $URL master" would result in
1042                  * ambiguity between remotes/origin/master and heads/master
1043                  * at the remote site.
1044                  */
1045                 if (namelen != patlen &&
1046                     patlen != namelen - 5 &&
1047                     !starts_with(name, "refs/heads/") &&
1048                     !starts_with(name, "refs/tags/")) {
1049                         /* We want to catch the case where only weak
1050                          * matches are found and there are multiple
1051                          * matches, and where more than one strong
1052                          * matches are found, as ambiguous.  One
1053                          * strong match with zero or more weak matches
1054                          * are acceptable as a unique match.
1055                          */
1056                         matched_weak = refs;
1057                         weak_match++;
1058                 }
1059                 else {
1060                         matched = refs;
1061                         match++;
1062                 }
1063         }
1064         if (!matched) {
1065                 *matched_ref = matched_weak;
1066                 return weak_match;
1067         }
1068         else {
1069                 *matched_ref = matched;
1070                 return match;
1071         }
1072 }
1073
1074 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1075 {
1076         **tail = ref;
1077         while (ref->next)
1078                 ref = ref->next;
1079         *tail = &ref->next;
1080 }
1081
1082 static struct ref *alloc_delete_ref(void)
1083 {
1084         struct ref *ref = alloc_ref("(delete)");
1085         hashclr(ref->new_sha1);
1086         return ref;
1087 }
1088
1089 static struct ref *try_explicit_object_name(const char *name)
1090 {
1091         unsigned char sha1[20];
1092         struct ref *ref;
1093
1094         if (!*name)
1095                 return alloc_delete_ref();
1096         if (get_sha1(name, sha1))
1097                 return NULL;
1098         ref = alloc_ref(name);
1099         hashcpy(ref->new_sha1, sha1);
1100         return ref;
1101 }
1102
1103 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1104 {
1105         struct ref *ret = alloc_ref(name);
1106         tail_link_ref(ret, tail);
1107         return ret;
1108 }
1109
1110 static char *guess_ref(const char *name, struct ref *peer)
1111 {
1112         struct strbuf buf = STRBUF_INIT;
1113         unsigned char sha1[20];
1114
1115         const char *r = resolve_ref_unsafe(peer->name, sha1, 1, NULL);
1116         if (!r)
1117                 return NULL;
1118
1119         if (starts_with(r, "refs/heads/"))
1120                 strbuf_addstr(&buf, "refs/heads/");
1121         else if (starts_with(r, "refs/tags/"))
1122                 strbuf_addstr(&buf, "refs/tags/");
1123         else
1124                 return NULL;
1125
1126         strbuf_addstr(&buf, name);
1127         return strbuf_detach(&buf, NULL);
1128 }
1129
1130 static int match_explicit(struct ref *src, struct ref *dst,
1131                           struct ref ***dst_tail,
1132                           struct refspec *rs)
1133 {
1134         struct ref *matched_src, *matched_dst;
1135         int copy_src;
1136
1137         const char *dst_value = rs->dst;
1138         char *dst_guess;
1139
1140         if (rs->pattern || rs->matching)
1141                 return 0;
1142
1143         matched_src = matched_dst = NULL;
1144         switch (count_refspec_match(rs->src, src, &matched_src)) {
1145         case 1:
1146                 copy_src = 1;
1147                 break;
1148         case 0:
1149                 /* The source could be in the get_sha1() format
1150                  * not a reference name.  :refs/other is a
1151                  * way to delete 'other' ref at the remote end.
1152                  */
1153                 matched_src = try_explicit_object_name(rs->src);
1154                 if (!matched_src)
1155                         return error("src refspec %s does not match any.", rs->src);
1156                 copy_src = 0;
1157                 break;
1158         default:
1159                 return error("src refspec %s matches more than one.", rs->src);
1160         }
1161
1162         if (!dst_value) {
1163                 unsigned char sha1[20];
1164                 int flag;
1165
1166                 dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
1167                 if (!dst_value ||
1168                     ((flag & REF_ISSYMREF) &&
1169                      !starts_with(dst_value, "refs/heads/")))
1170                         die("%s cannot be resolved to branch.",
1171                             matched_src->name);
1172         }
1173
1174         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1175         case 1:
1176                 break;
1177         case 0:
1178                 if (!memcmp(dst_value, "refs/", 5))
1179                         matched_dst = make_linked_ref(dst_value, dst_tail);
1180                 else if (is_null_sha1(matched_src->new_sha1))
1181                         error("unable to delete '%s': remote ref does not exist",
1182                               dst_value);
1183                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1184                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1185                 else
1186                         error("unable to push to unqualified destination: %s\n"
1187                               "The destination refspec neither matches an "
1188                               "existing ref on the remote nor\n"
1189                               "begins with refs/, and we are unable to "
1190                               "guess a prefix based on the source ref.",
1191                               dst_value);
1192                 break;
1193         default:
1194                 matched_dst = NULL;
1195                 error("dst refspec %s matches more than one.",
1196                       dst_value);
1197                 break;
1198         }
1199         if (!matched_dst)
1200                 return -1;
1201         if (matched_dst->peer_ref)
1202                 return error("dst ref %s receives from more than one src.",
1203                       matched_dst->name);
1204         else {
1205                 matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src;
1206                 matched_dst->force = rs->force;
1207         }
1208         return 0;
1209 }
1210
1211 static int match_explicit_refs(struct ref *src, struct ref *dst,
1212                                struct ref ***dst_tail, struct refspec *rs,
1213                                int rs_nr)
1214 {
1215         int i, errs;
1216         for (i = errs = 0; i < rs_nr; i++)
1217                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1218         return errs;
1219 }
1220
1221 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1222                 int send_mirror, int direction, const struct refspec **ret_pat)
1223 {
1224         const struct refspec *pat;
1225         char *name;
1226         int i;
1227         int matching_refs = -1;
1228         for (i = 0; i < rs_nr; i++) {
1229                 if (rs[i].matching &&
1230                     (matching_refs == -1 || rs[i].force)) {
1231                         matching_refs = i;
1232                         continue;
1233                 }
1234
1235                 if (rs[i].pattern) {
1236                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1237                         int match;
1238                         if (direction == FROM_SRC)
1239                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1240                         else
1241                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1242                         if (match) {
1243                                 matching_refs = i;
1244                                 break;
1245                         }
1246                 }
1247         }
1248         if (matching_refs == -1)
1249                 return NULL;
1250
1251         pat = rs + matching_refs;
1252         if (pat->matching) {
1253                 /*
1254                  * "matching refs"; traditionally we pushed everything
1255                  * including refs outside refs/heads/ hierarchy, but
1256                  * that does not make much sense these days.
1257                  */
1258                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1259                         return NULL;
1260                 name = xstrdup(ref->name);
1261         }
1262         if (ret_pat)
1263                 *ret_pat = pat;
1264         return name;
1265 }
1266
1267 static struct ref **tail_ref(struct ref **head)
1268 {
1269         struct ref **tail = head;
1270         while (*tail)
1271                 tail = &((*tail)->next);
1272         return tail;
1273 }
1274
1275 struct tips {
1276         struct commit **tip;
1277         int nr, alloc;
1278 };
1279
1280 static void add_to_tips(struct tips *tips, const unsigned char *sha1)
1281 {
1282         struct commit *commit;
1283
1284         if (is_null_sha1(sha1))
1285                 return;
1286         commit = lookup_commit_reference_gently(sha1, 1);
1287         if (!commit || (commit->object.flags & TMP_MARK))
1288                 return;
1289         commit->object.flags |= TMP_MARK;
1290         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1291         tips->tip[tips->nr++] = commit;
1292 }
1293
1294 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1295 {
1296         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1297         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1298         struct string_list_item *item;
1299         struct ref *ref;
1300         struct tips sent_tips;
1301
1302         /*
1303          * Collect everything we know they would have at the end of
1304          * this push, and collect all tags they have.
1305          */
1306         memset(&sent_tips, 0, sizeof(sent_tips));
1307         for (ref = *dst; ref; ref = ref->next) {
1308                 if (ref->peer_ref &&
1309                     !is_null_sha1(ref->peer_ref->new_sha1))
1310                         add_to_tips(&sent_tips, ref->peer_ref->new_sha1);
1311                 else
1312                         add_to_tips(&sent_tips, ref->old_sha1);
1313                 if (starts_with(ref->name, "refs/tags/"))
1314                         string_list_append(&dst_tag, ref->name);
1315         }
1316         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1317
1318         sort_string_list(&dst_tag);
1319
1320         /* Collect tags they do not have. */
1321         for (ref = src; ref; ref = ref->next) {
1322                 if (!starts_with(ref->name, "refs/tags/"))
1323                         continue; /* not a tag */
1324                 if (string_list_has_string(&dst_tag, ref->name))
1325                         continue; /* they already have it */
1326                 if (sha1_object_info(ref->new_sha1, NULL) != OBJ_TAG)
1327                         continue; /* be conservative */
1328                 item = string_list_append(&src_tag, ref->name);
1329                 item->util = ref;
1330         }
1331         string_list_clear(&dst_tag, 0);
1332
1333         /*
1334          * At this point, src_tag lists tags that are missing from
1335          * dst, and sent_tips lists the tips we are pushing or those
1336          * that we know they already have. An element in the src_tag
1337          * that is an ancestor of any of the sent_tips needs to be
1338          * sent to the other side.
1339          */
1340         if (sent_tips.nr) {
1341                 for_each_string_list_item(item, &src_tag) {
1342                         struct ref *ref = item->util;
1343                         struct ref *dst_ref;
1344                         struct commit *commit;
1345
1346                         if (is_null_sha1(ref->new_sha1))
1347                                 continue;
1348                         commit = lookup_commit_reference_gently(ref->new_sha1, 1);
1349                         if (!commit)
1350                                 /* not pushing a commit, which is not an error */
1351                                 continue;
1352
1353                         /*
1354                          * Is this tag, which they do not have, reachable from
1355                          * any of the commits we are sending?
1356                          */
1357                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1358                                 continue;
1359
1360                         /* Add it in */
1361                         dst_ref = make_linked_ref(ref->name, dst_tail);
1362                         hashcpy(dst_ref->new_sha1, ref->new_sha1);
1363                         dst_ref->peer_ref = copy_ref(ref);
1364                 }
1365         }
1366         string_list_clear(&src_tag, 0);
1367         free(sent_tips.tip);
1368 }
1369
1370 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1371 {
1372         for ( ; list; list = list->next)
1373                 if (!strcmp(list->name, name))
1374                         return (struct ref *)list;
1375         return NULL;
1376 }
1377
1378 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1379 {
1380         for ( ; ref; ref = ref->next)
1381                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1382
1383         sort_string_list(ref_index);
1384 }
1385
1386 /*
1387  * Given the set of refs the local repository has, the set of refs the
1388  * remote repository has, and the refspec used for push, determine
1389  * what remote refs we will update and with what value by setting
1390  * peer_ref (which object is being pushed) and force (if the push is
1391  * forced) in elements of "dst". The function may add new elements to
1392  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1393  */
1394 int match_push_refs(struct ref *src, struct ref **dst,
1395                     int nr_refspec, const char **refspec, int flags)
1396 {
1397         struct refspec *rs;
1398         int send_all = flags & MATCH_REFS_ALL;
1399         int send_mirror = flags & MATCH_REFS_MIRROR;
1400         int send_prune = flags & MATCH_REFS_PRUNE;
1401         int errs;
1402         static const char *default_refspec[] = { ":", NULL };
1403         struct ref *ref, **dst_tail = tail_ref(dst);
1404         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1405
1406         if (!nr_refspec) {
1407                 nr_refspec = 1;
1408                 refspec = default_refspec;
1409         }
1410         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1411         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1412
1413         /* pick the remainder */
1414         for (ref = src; ref; ref = ref->next) {
1415                 struct string_list_item *dst_item;
1416                 struct ref *dst_peer;
1417                 const struct refspec *pat = NULL;
1418                 char *dst_name;
1419
1420                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1421                 if (!dst_name)
1422                         continue;
1423
1424                 if (!dst_ref_index.nr)
1425                         prepare_ref_index(&dst_ref_index, *dst);
1426
1427                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1428                 dst_peer = dst_item ? dst_item->util : NULL;
1429                 if (dst_peer) {
1430                         if (dst_peer->peer_ref)
1431                                 /* We're already sending something to this ref. */
1432                                 goto free_name;
1433                 } else {
1434                         if (pat->matching && !(send_all || send_mirror))
1435                                 /*
1436                                  * Remote doesn't have it, and we have no
1437                                  * explicit pattern, and we don't have
1438                                  * --all or --mirror.
1439                                  */
1440                                 goto free_name;
1441
1442                         /* Create a new one and link it */
1443                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1444                         hashcpy(dst_peer->new_sha1, ref->new_sha1);
1445                         string_list_insert(&dst_ref_index,
1446                                 dst_peer->name)->util = dst_peer;
1447                 }
1448                 dst_peer->peer_ref = copy_ref(ref);
1449                 dst_peer->force = pat->force;
1450         free_name:
1451                 free(dst_name);
1452         }
1453
1454         string_list_clear(&dst_ref_index, 0);
1455
1456         if (flags & MATCH_REFS_FOLLOW_TAGS)
1457                 add_missing_tags(src, dst, &dst_tail);
1458
1459         if (send_prune) {
1460                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1461                 /* check for missing refs on the remote */
1462                 for (ref = *dst; ref; ref = ref->next) {
1463                         char *src_name;
1464
1465                         if (ref->peer_ref)
1466                                 /* We're already sending something to this ref. */
1467                                 continue;
1468
1469                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1470                         if (src_name) {
1471                                 if (!src_ref_index.nr)
1472                                         prepare_ref_index(&src_ref_index, src);
1473                                 if (!string_list_has_string(&src_ref_index,
1474                                             src_name))
1475                                         ref->peer_ref = alloc_delete_ref();
1476                                 free(src_name);
1477                         }
1478                 }
1479                 string_list_clear(&src_ref_index, 0);
1480         }
1481         if (errs)
1482                 return -1;
1483         return 0;
1484 }
1485
1486 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1487                              int force_update)
1488 {
1489         struct ref *ref;
1490
1491         for (ref = remote_refs; ref; ref = ref->next) {
1492                 int force_ref_update = ref->force || force_update;
1493                 int reject_reason = 0;
1494
1495                 if (ref->peer_ref)
1496                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1497                 else if (!send_mirror)
1498                         continue;
1499
1500                 ref->deletion = is_null_sha1(ref->new_sha1);
1501                 if (!ref->deletion &&
1502                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1503                         ref->status = REF_STATUS_UPTODATE;
1504                         continue;
1505                 }
1506
1507                 /*
1508                  * Bypass the usual "must fast-forward" check but
1509                  * replace it with a weaker "the old value must be
1510                  * this value we observed".  If the remote ref has
1511                  * moved and is now different from what we expect,
1512                  * reject any push.
1513                  *
1514                  * It also is an error if the user told us to check
1515                  * with the remote-tracking branch to find the value
1516                  * to expect, but we did not have such a tracking
1517                  * branch.
1518                  */
1519                 if (ref->expect_old_sha1) {
1520                         if (ref->expect_old_no_trackback ||
1521                             hashcmp(ref->old_sha1, ref->old_sha1_expect))
1522                                 reject_reason = REF_STATUS_REJECT_STALE;
1523                 }
1524
1525                 /*
1526                  * The usual "must fast-forward" rules.
1527                  *
1528                  * Decide whether an individual refspec A:B can be
1529                  * pushed.  The push will succeed if any of the
1530                  * following are true:
1531                  *
1532                  * (1) the remote reference B does not exist
1533                  *
1534                  * (2) the remote reference B is being removed (i.e.,
1535                  *     pushing :B where no source is specified)
1536                  *
1537                  * (3) the destination is not under refs/tags/, and
1538                  *     if the old and new value is a commit, the new
1539                  *     is a descendant of the old.
1540                  *
1541                  * (4) it is forced using the +A:B notation, or by
1542                  *     passing the --force argument
1543                  */
1544
1545                 else if (!ref->deletion && !is_null_sha1(ref->old_sha1)) {
1546                         if (starts_with(ref->name, "refs/tags/"))
1547                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1548                         else if (!has_sha1_file(ref->old_sha1))
1549                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1550                         else if (!lookup_commit_reference_gently(ref->old_sha1, 1) ||
1551                                  !lookup_commit_reference_gently(ref->new_sha1, 1))
1552                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1553                         else if (!ref_newer(ref->new_sha1, ref->old_sha1))
1554                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1555                 }
1556
1557                 /*
1558                  * "--force" will defeat any rejection implemented
1559                  * by the rules above.
1560                  */
1561                 if (!force_ref_update)
1562                         ref->status = reject_reason;
1563                 else if (reject_reason)
1564                         ref->forced_update = 1;
1565         }
1566 }
1567
1568 struct branch *branch_get(const char *name)
1569 {
1570         struct branch *ret;
1571
1572         read_config();
1573         if (!name || !*name || !strcmp(name, "HEAD"))
1574                 ret = current_branch;
1575         else
1576                 ret = make_branch(name, 0);
1577         if (ret && ret->remote_name) {
1578                 ret->remote = remote_get(ret->remote_name);
1579                 if (ret->merge_nr) {
1580                         int i;
1581                         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1582                         for (i = 0; i < ret->merge_nr; i++) {
1583                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1584                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1585                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1586                                     && !strcmp(ret->remote_name, "."))
1587                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1588                         }
1589                 }
1590         }
1591         return ret;
1592 }
1593
1594 int branch_has_merge_config(struct branch *branch)
1595 {
1596         return branch && !!branch->merge;
1597 }
1598
1599 int branch_merge_matches(struct branch *branch,
1600                                  int i,
1601                                  const char *refname)
1602 {
1603         if (!branch || i < 0 || i >= branch->merge_nr)
1604                 return 0;
1605         return refname_match(branch->merge[i]->src, refname);
1606 }
1607
1608 static int ignore_symref_update(const char *refname)
1609 {
1610         unsigned char sha1[20];
1611         int flag;
1612
1613         if (!resolve_ref_unsafe(refname, sha1, 0, &flag))
1614                 return 0; /* non-existing refs are OK */
1615         return (flag & REF_ISSYMREF);
1616 }
1617
1618 /*
1619  * Create and return a list of (struct ref) consisting of copies of
1620  * each remote_ref that matches refspec.  refspec must be a pattern.
1621  * Fill in the copies' peer_ref to describe the local tracking refs to
1622  * which they map.  Omit any references that would map to an existing
1623  * local symbolic ref.
1624  */
1625 static struct ref *get_expanded_map(const struct ref *remote_refs,
1626                                     const struct refspec *refspec)
1627 {
1628         const struct ref *ref;
1629         struct ref *ret = NULL;
1630         struct ref **tail = &ret;
1631
1632         for (ref = remote_refs; ref; ref = ref->next) {
1633                 char *expn_name = NULL;
1634
1635                 if (strchr(ref->name, '^'))
1636                         continue; /* a dereference item */
1637                 if (match_name_with_pattern(refspec->src, ref->name,
1638                                             refspec->dst, &expn_name) &&
1639                     !ignore_symref_update(expn_name)) {
1640                         struct ref *cpy = copy_ref(ref);
1641
1642                         cpy->peer_ref = alloc_ref(expn_name);
1643                         if (refspec->force)
1644                                 cpy->peer_ref->force = 1;
1645                         *tail = cpy;
1646                         tail = &cpy->next;
1647                 }
1648                 free(expn_name);
1649         }
1650
1651         return ret;
1652 }
1653
1654 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1655 {
1656         const struct ref *ref;
1657         for (ref = refs; ref; ref = ref->next) {
1658                 if (refname_match(name, ref->name))
1659                         return ref;
1660         }
1661         return NULL;
1662 }
1663
1664 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1665 {
1666         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1667
1668         if (!ref)
1669                 return NULL;
1670
1671         return copy_ref(ref);
1672 }
1673
1674 static struct ref *get_local_ref(const char *name)
1675 {
1676         if (!name || name[0] == '\0')
1677                 return NULL;
1678
1679         if (starts_with(name, "refs/"))
1680                 return alloc_ref(name);
1681
1682         if (starts_with(name, "heads/") ||
1683             starts_with(name, "tags/") ||
1684             starts_with(name, "remotes/"))
1685                 return alloc_ref_with_prefix("refs/", 5, name);
1686
1687         return alloc_ref_with_prefix("refs/heads/", 11, name);
1688 }
1689
1690 int get_fetch_map(const struct ref *remote_refs,
1691                   const struct refspec *refspec,
1692                   struct ref ***tail,
1693                   int missing_ok)
1694 {
1695         struct ref *ref_map, **rmp;
1696
1697         if (refspec->pattern) {
1698                 ref_map = get_expanded_map(remote_refs, refspec);
1699         } else {
1700                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1701
1702                 if (refspec->exact_sha1) {
1703                         ref_map = alloc_ref(name);
1704                         get_sha1_hex(name, ref_map->old_sha1);
1705                 } else {
1706                         ref_map = get_remote_ref(remote_refs, name);
1707                 }
1708                 if (!missing_ok && !ref_map)
1709                         die("Couldn't find remote ref %s", name);
1710                 if (ref_map) {
1711                         ref_map->peer_ref = get_local_ref(refspec->dst);
1712                         if (ref_map->peer_ref && refspec->force)
1713                                 ref_map->peer_ref->force = 1;
1714                 }
1715         }
1716
1717         for (rmp = &ref_map; *rmp; ) {
1718                 if ((*rmp)->peer_ref) {
1719                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1720                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1721                                 struct ref *ignore = *rmp;
1722                                 error("* Ignoring funny ref '%s' locally",
1723                                       (*rmp)->peer_ref->name);
1724                                 *rmp = (*rmp)->next;
1725                                 free(ignore->peer_ref);
1726                                 free(ignore);
1727                                 continue;
1728                         }
1729                 }
1730                 rmp = &((*rmp)->next);
1731         }
1732
1733         if (ref_map)
1734                 tail_link_ref(ref_map, tail);
1735
1736         return 0;
1737 }
1738
1739 int resolve_remote_symref(struct ref *ref, struct ref *list)
1740 {
1741         if (!ref->symref)
1742                 return 0;
1743         for (; list; list = list->next)
1744                 if (!strcmp(ref->symref, list->name)) {
1745                         hashcpy(ref->old_sha1, list->old_sha1);
1746                         return 0;
1747                 }
1748         return 1;
1749 }
1750
1751 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1752 {
1753         while (list) {
1754                 struct commit_list *temp = list;
1755                 temp->item->object.flags &= ~mark;
1756                 list = temp->next;
1757                 free(temp);
1758         }
1759 }
1760
1761 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1762 {
1763         struct object *o;
1764         struct commit *old, *new;
1765         struct commit_list *list, *used;
1766         int found = 0;
1767
1768         /*
1769          * Both new and old must be commit-ish and new is descendant of
1770          * old.  Otherwise we require --force.
1771          */
1772         o = deref_tag(parse_object(old_sha1), NULL, 0);
1773         if (!o || o->type != OBJ_COMMIT)
1774                 return 0;
1775         old = (struct commit *) o;
1776
1777         o = deref_tag(parse_object(new_sha1), NULL, 0);
1778         if (!o || o->type != OBJ_COMMIT)
1779                 return 0;
1780         new = (struct commit *) o;
1781
1782         if (parse_commit(new) < 0)
1783                 return 0;
1784
1785         used = list = NULL;
1786         commit_list_insert(new, &list);
1787         while (list) {
1788                 new = pop_most_recent_commit(&list, TMP_MARK);
1789                 commit_list_insert(new, &used);
1790                 if (new == old) {
1791                         found = 1;
1792                         break;
1793                 }
1794         }
1795         unmark_and_free(list, TMP_MARK);
1796         unmark_and_free(used, TMP_MARK);
1797         return found;
1798 }
1799
1800 /*
1801  * Compare a branch with its upstream, and save their differences (number
1802  * of commits) in *num_ours and *num_theirs.
1803  *
1804  * Return 0 if branch has no upstream (no base), -1 if upstream is missing
1805  * (with "gone" base), otherwise 1 (with base).
1806  */
1807 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1808 {
1809         unsigned char sha1[20];
1810         struct commit *ours, *theirs;
1811         char symmetric[84];
1812         struct rev_info revs;
1813         const char *rev_argv[10], *base;
1814         int rev_argc;
1815
1816         /* Cannot stat unless we are marked to build on top of somebody else. */
1817         if (!branch ||
1818             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1819                 return 0;
1820
1821         /* Cannot stat if what we used to build on no longer exists */
1822         base = branch->merge[0]->dst;
1823         if (read_ref(base, sha1))
1824                 return -1;
1825         theirs = lookup_commit_reference(sha1);
1826         if (!theirs)
1827                 return -1;
1828
1829         if (read_ref(branch->refname, sha1))
1830                 return -1;
1831         ours = lookup_commit_reference(sha1);
1832         if (!ours)
1833                 return -1;
1834
1835         /* are we the same? */
1836         if (theirs == ours) {
1837                 *num_theirs = *num_ours = 0;
1838                 return 1;
1839         }
1840
1841         /* Run "rev-list --left-right ours...theirs" internally... */
1842         rev_argc = 0;
1843         rev_argv[rev_argc++] = NULL;
1844         rev_argv[rev_argc++] = "--left-right";
1845         rev_argv[rev_argc++] = symmetric;
1846         rev_argv[rev_argc++] = "--";
1847         rev_argv[rev_argc] = NULL;
1848
1849         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1850         strcpy(symmetric + 40, "...");
1851         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1852
1853         init_revisions(&revs, NULL);
1854         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1855         prepare_revision_walk(&revs);
1856
1857         /* ... and count the commits on each side. */
1858         *num_ours = 0;
1859         *num_theirs = 0;
1860         while (1) {
1861                 struct commit *c = get_revision(&revs);
1862                 if (!c)
1863                         break;
1864                 if (c->object.flags & SYMMETRIC_LEFT)
1865                         (*num_ours)++;
1866                 else
1867                         (*num_theirs)++;
1868         }
1869
1870         /* clear object flags smudged by the above traversal */
1871         clear_commit_marks(ours, ALL_REV_FLAGS);
1872         clear_commit_marks(theirs, ALL_REV_FLAGS);
1873         return 1;
1874 }
1875
1876 /*
1877  * Return true when there is anything to report, otherwise false.
1878  */
1879 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1880 {
1881         int ours, theirs;
1882         const char *base;
1883         int upstream_is_gone = 0;
1884
1885         switch (stat_tracking_info(branch, &ours, &theirs)) {
1886         case 0:
1887                 /* no base */
1888                 return 0;
1889         case -1:
1890                 /* with "gone" base */
1891                 upstream_is_gone = 1;
1892                 break;
1893         default:
1894                 /* with base */
1895                 break;
1896         }
1897
1898         base = branch->merge[0]->dst;
1899         base = shorten_unambiguous_ref(base, 0);
1900         if (upstream_is_gone) {
1901                 strbuf_addf(sb,
1902                         _("Your branch is based on '%s', but the upstream is gone.\n"),
1903                         base);
1904                 if (advice_status_hints)
1905                         strbuf_addf(sb,
1906                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
1907         } else if (!ours && !theirs) {
1908                 strbuf_addf(sb,
1909                         _("Your branch is up-to-date with '%s'.\n"),
1910                         base);
1911         } else if (!theirs) {
1912                 strbuf_addf(sb,
1913                         Q_("Your branch is ahead of '%s' by %d commit.\n",
1914                            "Your branch is ahead of '%s' by %d commits.\n",
1915                            ours),
1916                         base, ours);
1917                 if (advice_status_hints)
1918                         strbuf_addf(sb,
1919                                 _("  (use \"git push\" to publish your local commits)\n"));
1920         } else if (!ours) {
1921                 strbuf_addf(sb,
1922                         Q_("Your branch is behind '%s' by %d commit, "
1923                                "and can be fast-forwarded.\n",
1924                            "Your branch is behind '%s' by %d commits, "
1925                                "and can be fast-forwarded.\n",
1926                            theirs),
1927                         base, theirs);
1928                 if (advice_status_hints)
1929                         strbuf_addf(sb,
1930                                 _("  (use \"git pull\" to update your local branch)\n"));
1931         } else {
1932                 strbuf_addf(sb,
1933                         Q_("Your branch and '%s' have diverged,\n"
1934                                "and have %d and %d different commit each, "
1935                                "respectively.\n",
1936                            "Your branch and '%s' have diverged,\n"
1937                                "and have %d and %d different commits each, "
1938                                "respectively.\n",
1939                            theirs),
1940                         base, ours, theirs);
1941                 if (advice_status_hints)
1942                         strbuf_addf(sb,
1943                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
1944         }
1945         return 1;
1946 }
1947
1948 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1949 {
1950         struct ref ***local_tail = cb_data;
1951         struct ref *ref;
1952         int len;
1953
1954         /* we already know it starts with refs/ to get here */
1955         if (check_refname_format(refname + 5, 0))
1956                 return 0;
1957
1958         len = strlen(refname) + 1;
1959         ref = xcalloc(1, sizeof(*ref) + len);
1960         hashcpy(ref->new_sha1, sha1);
1961         memcpy(ref->name, refname, len);
1962         **local_tail = ref;
1963         *local_tail = &ref->next;
1964         return 0;
1965 }
1966
1967 struct ref *get_local_heads(void)
1968 {
1969         struct ref *local_refs = NULL, **local_tail = &local_refs;
1970         for_each_ref(one_local_ref, &local_tail);
1971         return local_refs;
1972 }
1973
1974 struct ref *guess_remote_head(const struct ref *head,
1975                               const struct ref *refs,
1976                               int all)
1977 {
1978         const struct ref *r;
1979         struct ref *list = NULL;
1980         struct ref **tail = &list;
1981
1982         if (!head)
1983                 return NULL;
1984
1985         /*
1986          * Some transports support directly peeking at
1987          * where HEAD points; if that is the case, then
1988          * we don't have to guess.
1989          */
1990         if (head->symref)
1991                 return copy_ref(find_ref_by_name(refs, head->symref));
1992
1993         /* If refs/heads/master could be right, it is. */
1994         if (!all) {
1995                 r = find_ref_by_name(refs, "refs/heads/master");
1996                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
1997                         return copy_ref(r);
1998         }
1999
2000         /* Look for another ref that points there */
2001         for (r = refs; r; r = r->next) {
2002                 if (r != head &&
2003                     starts_with(r->name, "refs/heads/") &&
2004                     !hashcmp(r->old_sha1, head->old_sha1)) {
2005                         *tail = copy_ref(r);
2006                         tail = &((*tail)->next);
2007                         if (!all)
2008                                 break;
2009                 }
2010         }
2011
2012         return list;
2013 }
2014
2015 struct stale_heads_info {
2016         struct string_list *ref_names;
2017         struct ref **stale_refs_tail;
2018         struct refspec *refs;
2019         int ref_count;
2020 };
2021
2022 static int get_stale_heads_cb(const char *refname,
2023         const unsigned char *sha1, int flags, void *cb_data)
2024 {
2025         struct stale_heads_info *info = cb_data;
2026         struct string_list matches = STRING_LIST_INIT_DUP;
2027         struct refspec query;
2028         int i, stale = 1;
2029         memset(&query, 0, sizeof(struct refspec));
2030         query.dst = (char *)refname;
2031
2032         query_refspecs_multiple(info->refs, info->ref_count, &query, &matches);
2033         if (matches.nr == 0)
2034                 goto clean_exit; /* No matches */
2035
2036         /*
2037          * If we did find a suitable refspec and it's not a symref and
2038          * it's not in the list of refs that currently exist in that
2039          * remote, we consider it to be stale. In order to deal with
2040          * overlapping refspecs, we need to go over all of the
2041          * matching refs.
2042          */
2043         if (flags & REF_ISSYMREF)
2044                 goto clean_exit;
2045
2046         for (i = 0; stale && i < matches.nr; i++)
2047                 if (string_list_has_string(info->ref_names, matches.items[i].string))
2048                         stale = 0;
2049
2050         if (stale) {
2051                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2052                 hashcpy(ref->new_sha1, sha1);
2053         }
2054
2055 clean_exit:
2056         string_list_clear(&matches, 0);
2057         return 0;
2058 }
2059
2060 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
2061 {
2062         struct ref *ref, *stale_refs = NULL;
2063         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2064         struct stale_heads_info info;
2065         info.ref_names = &ref_names;
2066         info.stale_refs_tail = &stale_refs;
2067         info.refs = refs;
2068         info.ref_count = ref_count;
2069         for (ref = fetch_map; ref; ref = ref->next)
2070                 string_list_append(&ref_names, ref->name);
2071         sort_string_list(&ref_names);
2072         for_each_ref(get_stale_heads_cb, &info);
2073         string_list_clear(&ref_names, 0);
2074         return stale_refs;
2075 }
2076
2077 /*
2078  * Compare-and-swap
2079  */
2080 void clear_cas_option(struct push_cas_option *cas)
2081 {
2082         int i;
2083
2084         for (i = 0; i < cas->nr; i++)
2085                 free(cas->entry[i].refname);
2086         free(cas->entry);
2087         memset(cas, 0, sizeof(*cas));
2088 }
2089
2090 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2091                                       const char *refname,
2092                                       size_t refnamelen)
2093 {
2094         struct push_cas *entry;
2095         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2096         entry = &cas->entry[cas->nr++];
2097         memset(entry, 0, sizeof(*entry));
2098         entry->refname = xmemdupz(refname, refnamelen);
2099         return entry;
2100 }
2101
2102 int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2103 {
2104         const char *colon;
2105         struct push_cas *entry;
2106
2107         if (unset) {
2108                 /* "--no-<option>" */
2109                 clear_cas_option(cas);
2110                 return 0;
2111         }
2112
2113         if (!arg) {
2114                 /* just "--<option>" */
2115                 cas->use_tracking_for_rest = 1;
2116                 return 0;
2117         }
2118
2119         /* "--<option>=refname" or "--<option>=refname:value" */
2120         colon = strchrnul(arg, ':');
2121         entry = add_cas_entry(cas, arg, colon - arg);
2122         if (!*colon)
2123                 entry->use_tracking = 1;
2124         else if (get_sha1(colon + 1, entry->expect))
2125                 return error("cannot parse expected object name '%s'", colon + 1);
2126         return 0;
2127 }
2128
2129 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2130 {
2131         return parse_push_cas_option(opt->value, arg, unset);
2132 }
2133
2134 int is_empty_cas(const struct push_cas_option *cas)
2135 {
2136         return !cas->use_tracking_for_rest && !cas->nr;
2137 }
2138
2139 /*
2140  * Look at remote.fetch refspec and see if we have a remote
2141  * tracking branch for the refname there.  Fill its current
2142  * value in sha1[].
2143  * If we cannot do so, return negative to signal an error.
2144  */
2145 static int remote_tracking(struct remote *remote, const char *refname,
2146                            unsigned char sha1[20])
2147 {
2148         char *dst;
2149
2150         dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
2151         if (!dst)
2152                 return -1; /* no tracking ref for refname at remote */
2153         if (read_ref(dst, sha1))
2154                 return -1; /* we know what the tracking ref is but we cannot read it */
2155         return 0;
2156 }
2157
2158 static void apply_cas(struct push_cas_option *cas,
2159                       struct remote *remote,
2160                       struct ref *ref)
2161 {
2162         int i;
2163
2164         /* Find an explicit --<option>=<name>[:<value>] entry */
2165         for (i = 0; i < cas->nr; i++) {
2166                 struct push_cas *entry = &cas->entry[i];
2167                 if (!refname_match(entry->refname, ref->name))
2168                         continue;
2169                 ref->expect_old_sha1 = 1;
2170                 if (!entry->use_tracking)
2171                         hashcpy(ref->old_sha1_expect, cas->entry[i].expect);
2172                 else if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2173                         ref->expect_old_no_trackback = 1;
2174                 return;
2175         }
2176
2177         /* Are we using "--<option>" to cover all? */
2178         if (!cas->use_tracking_for_rest)
2179                 return;
2180
2181         ref->expect_old_sha1 = 1;
2182         if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2183                 ref->expect_old_no_trackback = 1;
2184 }
2185
2186 void apply_push_cas(struct push_cas_option *cas,
2187                     struct remote *remote,
2188                     struct ref *remote_refs)
2189 {
2190         struct ref *ref;
2191         for (ref = remote_refs; ref; ref = ref->next)
2192                 apply_cas(cas, remote, ref);
2193 }