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 (git_config_string(&branch->pushremote_name, key, value))
 356                                 return -1;
 357                         if (branch == current_branch)
 358                                 branch_pushremote_name = xstrdup(branch->pushremote_name);
 359                 } else if (!strcmp(subkey, ".merge")) {
 360                         if (!value)
 361                                 return config_error_nonbool(key);
 362                         add_merge(branch, xstrdup(value));
 363                 } else if (!strcmp(subkey, ".push")) {
 364                         if (git_config_string(&branch->push_name, key, value))
 365                                 return -1;
 366                 }
 367                 return 0;
 368         }
 369         if (starts_with(key, "url.")) {
 370                 struct rewrite *rewrite;
 371                 name = key + 4;
 372                 subkey = strrchr(name, '.');
 373                 if (!subkey)
 374                         return 0;
 375                 if (!strcmp(subkey, ".insteadof")) {
 376                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 377                         if (!value)
 378                                 return config_error_nonbool(key);
 379                         add_instead_of(rewrite, xstrdup(value));
 380                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 381                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 382                         if (!value)
 383                                 return config_error_nonbool(key);
 384                         add_instead_of(rewrite, xstrdup(value));
 385                 }
 386         }
 387
 388         if (!starts_with(key,  "remote."))
 389                 return 0;
 390         name = key + 7;
 391
 392         /* Handle remote.* variables */
 393         if (!strcmp(name, "pushdefault"))
 394                 return git_config_string(&pushremote_name, key, value);
 395
 396         /* Handle remote.<name>.* variables */
 397         if (*name == '/') {
 398                 warning("Config remote shorthand cannot begin with '/': %s",
 399                         name);
 400                 return 0;
 401         }
 402         subkey = strrchr(name, '.');
 403         if (!subkey)
 404                 return 0;
 405         remote = make_remote(name, subkey - name);
 406         remote->origin = REMOTE_CONFIG;
 407         if (!strcmp(subkey, ".mirror"))
 408                 remote->mirror = git_config_bool(key, value);
 409         else if (!strcmp(subkey, ".skipdefaultupdate"))
 410                 remote->skip_default_update = git_config_bool(key, value);
 411         else if (!strcmp(subkey, ".skipfetchall"))
 412                 remote->skip_default_update = git_config_bool(key, value);
 413         else if (!strcmp(subkey, ".prune"))
 414                 remote->prune = git_config_bool(key, value);
 415         else if (!strcmp(subkey, ".url")) {
 416                 const char *v;
 417                 if (git_config_string(&v, key, value))
 418                         return -1;
 419                 add_url(remote, v);
 420         } else if (!strcmp(subkey, ".pushurl")) {
 421                 const char *v;
 422                 if (git_config_string(&v, key, value))
 423                         return -1;
 424                 add_pushurl(remote, v);
 425         } else if (!strcmp(subkey, ".push")) {
 426                 const char *v;
 427                 if (git_config_string(&v, key, value))
 428                         return -1;
 429                 add_push_refspec(remote, v);
 430         } else if (!strcmp(subkey, ".fetch")) {
 431                 const char *v;
 432                 if (git_config_string(&v, key, value))
 433                         return -1;
 434                 add_fetch_refspec(remote, v);
 435         } else if (!strcmp(subkey, ".receivepack")) {
 436                 const char *v;
 437                 if (git_config_string(&v, key, value))
 438                         return -1;
 439                 if (!remote->receivepack)
 440                         remote->receivepack = v;
 441                 else
 442                         error("more than one receivepack given, using the first");
 443         } else if (!strcmp(subkey, ".uploadpack")) {
 444                 const char *v;
 445                 if (git_config_string(&v, key, value))
 446                         return -1;
 447                 if (!remote->uploadpack)
 448                         remote->uploadpack = v;
 449                 else
 450                         error("more than one uploadpack given, using the first");
 451         } else if (!strcmp(subkey, ".tagopt")) {
 452                 if (!strcmp(value, "--no-tags"))
 453                         remote->fetch_tags = -1;
 454                 else if (!strcmp(value, "--tags"))
 455                         remote->fetch_tags = 2;
 456         } else if (!strcmp(subkey, ".proxy")) {
 457                 return git_config_string((const char **)&remote->http_proxy,
 458                                          key, value);
 459         } else if (!strcmp(subkey, ".vcs")) {
 460                 return git_config_string(&remote->foreign_vcs, key, value);
 461         }
 462         return 0;
 463 }
 464
 465 static void alias_all_urls(void)
 466 {
 467         int i, j;
 468         for (i = 0; i < remotes_nr; i++) {
 469                 int add_pushurl_aliases;
 470                 if (!remotes[i])
 471                         continue;
 472                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 473                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 474                 }
 475                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 476                 for (j = 0; j < remotes[i]->url_nr; j++) {
 477                         if (add_pushurl_aliases)
 478                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 479                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 480                 }
 481         }
 482 }
 483
 484 static void read_config(void)
 485 {
 486         unsigned char sha1[20];
 487         const char *head_ref;
 488         int flag;
 489         if (default_remote_name) /* did this already */
 490                 return;
 491         default_remote_name = "origin";
 492         current_branch = NULL;
 493         head_ref = resolve_ref_unsafe("HEAD", sha1, 0, &flag);
 494         if (head_ref && (flag & REF_ISSYMREF) &&
 495             starts_with(head_ref, "refs/heads/")) {
 496                 current_branch =
 497                         make_branch(head_ref + strlen("refs/heads/"), 0);
 498         }
 499         git_config(handle_config, NULL);
 500         if (branch_pushremote_name) {
 501                 free((char *)pushremote_name);
 502                 pushremote_name = branch_pushremote_name;
 503         }
 504         alias_all_urls();
 505 }
 506
 507 /*
 508  * This function frees a refspec array.
 509  * Warning: code paths should be checked to ensure that the src
 510  *          and dst pointers are always freeable pointers as well
 511  *          as the refspec pointer itself.
 512  */
 513 static void free_refspecs(struct refspec *refspec, int nr_refspec)
 514 {
 515         int i;
 516
 517         if (!refspec)
 518                 return;
 519
 520         for (i = 0; i < nr_refspec; i++) {
 521                 free(refspec[i].src);
 522                 free(refspec[i].dst);
 523         }
 524         free(refspec);
 525 }
 526
 527 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 528 {
 529         int i;
 530         struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 531
 532         for (i = 0; i < nr_refspec; i++) {
 533                 size_t llen;
 534                 int is_glob;
 535                 const char *lhs, *rhs;
 536                 int flags;
 537
 538                 is_glob = 0;
 539
 540                 lhs = refspec[i];
 541                 if (*lhs == '+') {
 542                         rs[i].force = 1;
 543                         lhs++;
 544                 }
 545
 546                 rhs = strrchr(lhs, ':');
 547
 548                 /*
 549                  * Before going on, special case ":" (or "+:") as a refspec
 550                  * for pushing matching refs.
 551                  */
 552                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
 553                         rs[i].matching = 1;
 554                         continue;
 555                 }
 556
 557                 if (rhs) {
 558                         size_t rlen = strlen(++rhs);
 559                         is_glob = (1 <= rlen && strchr(rhs, '*'));
 560                         rs[i].dst = xstrndup(rhs, rlen);
 561                 }
 562
 563                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 564                 if (1 <= llen && memchr(lhs, '*', llen)) {
 565                         if ((rhs && !is_glob) || (!rhs && fetch))
 566                                 goto invalid;
 567                         is_glob = 1;
 568                 } else if (rhs && is_glob) {
 569                         goto invalid;
 570                 }
 571
 572                 rs[i].pattern = is_glob;
 573                 rs[i].src = xstrndup(lhs, llen);
 574                 flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
 575
 576                 if (fetch) {
 577                         unsigned char unused[40];
 578
 579                         /* LHS */
 580                         if (!*rs[i].src)
 581                                 ; /* empty is ok; it means "HEAD" */
 582                         else if (llen == 40 && !get_sha1_hex(rs[i].src, unused))
 583                                 rs[i].exact_sha1 = 1; /* ok */
 584                         else if (!check_refname_format(rs[i].src, flags))
 585                                 ; /* valid looking ref is ok */
 586                         else
 587                                 goto invalid;
 588                         /* RHS */
 589                         if (!rs[i].dst)
 590                                 ; /* missing is ok; it is the same as empty */
 591                         else if (!*rs[i].dst)
 592                                 ; /* empty is ok; it means "do not store" */
 593                         else if (!check_refname_format(rs[i].dst, flags))
 594                                 ; /* valid looking ref is ok */
 595                         else
 596                                 goto invalid;
 597                 } else {
 598                         /*
 599                          * LHS
 600                          * - empty is allowed; it means delete.
 601                          * - when wildcarded, it must be a valid looking ref.
 602                          * - otherwise, it must be an extended SHA-1, but
 603                          *   there is no existing way to validate this.
 604                          */
 605                         if (!*rs[i].src)
 606                                 ; /* empty is ok */
 607                         else if (is_glob) {
 608                                 if (check_refname_format(rs[i].src, flags))
 609                                         goto invalid;
 610                         }
 611                         else
 612                                 ; /* anything goes, for now */
 613                         /*
 614                          * RHS
 615                          * - missing is allowed, but LHS then must be a
 616                          *   valid looking ref.
 617                          * - empty is not allowed.
 618                          * - otherwise it must be a valid looking ref.
 619                          */
 620                         if (!rs[i].dst) {
 621                                 if (check_refname_format(rs[i].src, flags))
 622                                         goto invalid;
 623                         } else if (!*rs[i].dst) {
 624                                 goto invalid;
 625                         } else {
 626                                 if (check_refname_format(rs[i].dst, flags))
 627                                         goto invalid;
 628                         }
 629                 }
 630         }
 631         return rs;
 632
 633  invalid:
 634         if (verify) {
 635                 /*
 636                  * nr_refspec must be greater than zero and i must be valid
 637                  * since it is only possible to reach this point from within
 638                  * the for loop above.
 639                  */
 640                 free_refspecs(rs, i+1);
 641                 return NULL;
 642         }
 643         die("Invalid refspec '%s'", refspec[i]);
 644 }
 645
 646 int valid_fetch_refspec(const char *fetch_refspec_str)
 647 {
 648         struct refspec *refspec;
 649
 650         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
 651         free_refspecs(refspec, 1);
 652         return !!refspec;
 653 }
 654
 655 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 656 {
 657         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 658 }
 659
 660 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 661 {
 662         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 663 }
 664
 665 void free_refspec(int nr_refspec, struct refspec *refspec)
 666 {
 667         int i;
 668         for (i = 0; i < nr_refspec; i++) {
 669                 free(refspec[i].src);
 670                 free(refspec[i].dst);
 671         }
 672         free(refspec);
 673 }
 674
 675 static int valid_remote_nick(const char *name)
 676 {
 677         if (!name[0] || is_dot_or_dotdot(name))
 678                 return 0;
 679         return !strchr(name, '/'); /* no slash */
 680 }
 681
 682 static struct remote *remote_get_1(const char *name, const char *pushremote_name)
 683 {
 684         struct remote *ret;
 685         int name_given = 0;
 686
 687         if (name)
 688                 name_given = 1;
 689         else {
 690                 if (pushremote_name) {
 691                         name = pushremote_name;
 692                         name_given = 1;
 693                 } else {
 694                         name = default_remote_name;
 695                         name_given = explicit_default_remote_name;
 696                 }
 697         }
 698
 699         ret = make_remote(name, 0);
 700         if (valid_remote_nick(name)) {
 701                 if (!valid_remote(ret))
 702                         read_remotes_file(ret);
 703                 if (!valid_remote(ret))
 704                         read_branches_file(ret);
 705         }
 706         if (name_given && !valid_remote(ret))
 707                 add_url_alias(ret, name);
 708         if (!valid_remote(ret))
 709                 return NULL;
 710         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 711         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 712         return ret;
 713 }
 714
 715 struct remote *remote_get(const char *name)
 716 {
 717         read_config();
 718         return remote_get_1(name, NULL);
 719 }
 720
 721 struct remote *pushremote_get(const char *name)
 722 {
 723         read_config();
 724         return remote_get_1(name, pushremote_name);
 725 }
 726
 727 int remote_is_configured(const char *name)
 728 {
 729         int i;
 730         read_config();
 731
 732         for (i = 0; i < remotes_nr; i++)
 733                 if (!strcmp(name, remotes[i]->name))
 734                         return 1;
 735         return 0;
 736 }
 737
 738 int for_each_remote(each_remote_fn fn, void *priv)
 739 {
 740         int i, result = 0;
 741         read_config();
 742         for (i = 0; i < remotes_nr && !result; i++) {
 743                 struct remote *r = remotes[i];
 744                 if (!r)
 745                         continue;
 746                 if (!r->fetch)
 747                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 748                                                        r->fetch_refspec);
 749                 if (!r->push)
 750                         r->push = parse_push_refspec(r->push_refspec_nr,
 751                                                      r->push_refspec);
 752                 result = fn(r, priv);
 753         }
 754         return result;
 755 }
 756
 757 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
 758 {
 759         if (strcmp(ref1->name, ref2->name)) {
 760                 if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 761                     ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
 762                         die(_("Cannot fetch both %s and %s to %s"),
 763                             ref1->name, ref2->name, ref2->peer_ref->name);
 764                 } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 765                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 766                         warning(_("%s usually tracks %s, not %s"),
 767                                 ref2->peer_ref->name, ref2->name, ref1->name);
 768                 } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
 769                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 770                         die(_("%s tracks both %s and %s"),
 771                             ref2->peer_ref->name, ref1->name, ref2->name);
 772                 } else {
 773                         /*
 774                          * This last possibility doesn't occur because
 775                          * FETCH_HEAD_IGNORE entries always appear at
 776                          * the end of the list.
 777                          */
 778                         die(_("Internal error"));
 779                 }
 780         }
 781         free(ref2->peer_ref);
 782         free(ref2);
 783 }
 784
 785 struct ref *ref_remove_duplicates(struct ref *ref_map)
 786 {
 787         struct string_list refs = STRING_LIST_INIT_NODUP;
 788         struct ref *retval = NULL;
 789         struct ref **p = &retval;
 790
 791         while (ref_map) {
 792                 struct ref *ref = ref_map;
 793
 794                 ref_map = ref_map->next;
 795                 ref->next = NULL;
 796
 797                 if (!ref->peer_ref) {
 798                         *p = ref;
 799                         p = &ref->next;
 800                 } else {
 801                         struct string_list_item *item =
 802                                 string_list_insert(&refs, ref->peer_ref->name);
 803
 804                         if (item->util) {
 805                                 /* Entry already existed */
 806                                 handle_duplicate((struct ref *)item->util, ref);
 807                         } else {
 808                                 *p = ref;
 809                                 p = &ref->next;
 810                                 item->util = ref;
 811                         }
 812                 }
 813         }
 814
 815         string_list_clear(&refs, 0);
 816         return retval;
 817 }
 818
 819 int remote_has_url(struct remote *remote, const char *url)
 820 {
 821         int i;
 822         for (i = 0; i < remote->url_nr; i++) {
 823                 if (!strcmp(remote->url[i], url))
 824                         return 1;
 825         }
 826         return 0;
 827 }
 828
 829 static int match_name_with_pattern(const char *key, const char *name,
 830                                    const char *value, char **result)
 831 {
 832         const char *kstar = strchr(key, '*');
 833         size_t klen;
 834         size_t ksuffixlen;
 835         size_t namelen;
 836         int ret;
 837         if (!kstar)
 838                 die("Key '%s' of pattern had no '*'", key);
 839         klen = kstar - key;
 840         ksuffixlen = strlen(kstar + 1);
 841         namelen = strlen(name);
 842         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 843                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 844         if (ret && value) {
 845                 const char *vstar = strchr(value, '*');
 846                 size_t vlen;
 847                 size_t vsuffixlen;
 848                 if (!vstar)
 849                         die("Value '%s' of pattern has no '*'", value);
 850                 vlen = vstar - value;
 851                 vsuffixlen = strlen(vstar + 1);
 852                 *result = xmalloc(vlen + vsuffixlen +
 853                                   strlen(name) -
 854                                   klen - ksuffixlen + 1);
 855                 strncpy(*result, value, vlen);
 856                 strncpy(*result + vlen,
 857                         name + klen, namelen - klen - ksuffixlen);
 858                 strcpy(*result + vlen + namelen - klen - ksuffixlen,
 859                        vstar + 1);
 860         }
 861         return ret;
 862 }
 863
 864 static void query_refspecs_multiple(struct refspec *refs, int ref_count, struct refspec *query, struct string_list *results)
 865 {
 866         int i;
 867         int find_src = !query->src;
 868
 869         if (find_src && !query->dst)
 870                 error("query_refspecs_multiple: need either src or dst");
 871
 872         for (i = 0; i < ref_count; i++) {
 873                 struct refspec *refspec = &refs[i];
 874                 const char *key = find_src ? refspec->dst : refspec->src;
 875                 const char *value = find_src ? refspec->src : refspec->dst;
 876                 const char *needle = find_src ? query->dst : query->src;
 877                 char **result = find_src ? &query->src : &query->dst;
 878
 879                 if (!refspec->dst)
 880                         continue;
 881                 if (refspec->pattern) {
 882                         if (match_name_with_pattern(key, needle, value, result))
 883                                 string_list_append_nodup(results, *result);
 884                 } else if (!strcmp(needle, key)) {
 885                         string_list_append(results, value);
 886                 }
 887         }
 888 }
 889
 890 int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
 891 {
 892         int i;
 893         int find_src = !query->src;
 894         const char *needle = find_src ? query->dst : query->src;
 895         char **result = find_src ? &query->src : &query->dst;
 896
 897         if (find_src && !query->dst)
 898                 return error("query_refspecs: need either src or dst");
 899
 900         for (i = 0; i < ref_count; i++) {
 901                 struct refspec *refspec = &refs[i];
 902                 const char *key = find_src ? refspec->dst : refspec->src;
 903                 const char *value = find_src ? refspec->src : refspec->dst;
 904
 905                 if (!refspec->dst)
 906                         continue;
 907                 if (refspec->pattern) {
 908                         if (match_name_with_pattern(key, needle, value, result)) {
 909                                 query->force = refspec->force;
 910                                 return 0;
 911                         }
 912                 } else if (!strcmp(needle, key)) {
 913                         *result = xstrdup(value);
 914                         query->force = refspec->force;
 915                         return 0;
 916                 }
 917         }
 918         return -1;
 919 }
 920
 921 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 922                      const char *name)
 923 {
 924         struct refspec query;
 925
 926         memset(&query, 0, sizeof(struct refspec));
 927         query.src = (char *)name;
 928
 929         if (query_refspecs(refspecs, nr_refspec, &query))
 930                 return NULL;
 931
 932         return query.dst;
 933 }
 934
 935 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 936 {
 937         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
 938 }
 939
 940 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 941                 const char *name)
 942 {
 943         size_t len = strlen(name);
 944         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 945         memcpy(ref->name, prefix, prefixlen);
 946         memcpy(ref->name + prefixlen, name, len);
 947         return ref;
 948 }
 949
 950 struct ref *alloc_ref(const char *name)
 951 {
 952         return alloc_ref_with_prefix("", 0, name);
 953 }
 954
 955 struct ref *copy_ref(const struct ref *ref)
 956 {
 957         struct ref *cpy;
 958         size_t len;
 959         if (!ref)
 960                 return NULL;
 961         len = strlen(ref->name);
 962         cpy = xmalloc(sizeof(struct ref) + len + 1);
 963         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 964         cpy->next = NULL;
 965         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 966         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 967         cpy->peer_ref = copy_ref(ref->peer_ref);
 968         return cpy;
 969 }
 970
 971 struct ref *copy_ref_list(const struct ref *ref)
 972 {
 973         struct ref *ret = NULL;
 974         struct ref **tail = &ret;
 975         while (ref) {
 976                 *tail = copy_ref(ref);
 977                 ref = ref->next;
 978                 tail = &((*tail)->next);
 979         }
 980         return ret;
 981 }
 982
 983 static void free_ref(struct ref *ref)
 984 {
 985         if (!ref)
 986                 return;
 987         free_ref(ref->peer_ref);
 988         free(ref->remote_status);
 989         free(ref->symref);
 990         free(ref);
 991 }
 992
 993 void free_refs(struct ref *ref)
 994 {
 995         struct ref *next;
 996         while (ref) {
 997                 next = ref->next;
 998                 free_ref(ref);
 999                 ref = next;
1000         }
1001 }
1002
1003 int ref_compare_name(const void *va, const void *vb)
1004 {
1005         const struct ref *a = va, *b = vb;
1006         return strcmp(a->name, b->name);
1007 }
1008
1009 static void *ref_list_get_next(const void *a)
1010 {
1011         return ((const struct ref *)a)->next;
1012 }
1013
1014 static void ref_list_set_next(void *a, void *next)
1015 {
1016         ((struct ref *)a)->next = next;
1017 }
1018
1019 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
1020 {
1021         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
1022 }
1023
1024 int count_refspec_match(const char *pattern,
1025                         struct ref *refs,
1026                         struct ref **matched_ref)
1027 {
1028         int patlen = strlen(pattern);
1029         struct ref *matched_weak = NULL;
1030         struct ref *matched = NULL;
1031         int weak_match = 0;
1032         int match = 0;
1033
1034         for (weak_match = match = 0; refs; refs = refs->next) {
1035                 char *name = refs->name;
1036                 int namelen = strlen(name);
1037
1038                 if (!refname_match(pattern, name))
1039                         continue;
1040
1041                 /* A match is "weak" if it is with refs outside
1042                  * heads or tags, and did not specify the pattern
1043                  * in full (e.g. "refs/remotes/origin/master") or at
1044                  * least from the toplevel (e.g. "remotes/origin/master");
1045                  * otherwise "git push $URL master" would result in
1046                  * ambiguity between remotes/origin/master and heads/master
1047                  * at the remote site.
1048                  */
1049                 if (namelen != patlen &&
1050                     patlen != namelen - 5 &&
1051                     !starts_with(name, "refs/heads/") &&
1052                     !starts_with(name, "refs/tags/")) {
1053                         /* We want to catch the case where only weak
1054                          * matches are found and there are multiple
1055                          * matches, and where more than one strong
1056                          * matches are found, as ambiguous.  One
1057                          * strong match with zero or more weak matches
1058                          * are acceptable as a unique match.
1059                          */
1060                         matched_weak = refs;
1061                         weak_match++;
1062                 }
1063                 else {
1064                         matched = refs;
1065                         match++;
1066                 }
1067         }
1068         if (!matched) {
1069                 if (matched_ref)
1070                         *matched_ref = matched_weak;
1071                 return weak_match;
1072         }
1073         else {
1074                 if (matched_ref)
1075                         *matched_ref = matched;
1076                 return match;
1077         }
1078 }
1079
1080 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1081 {
1082         **tail = ref;
1083         while (ref->next)
1084                 ref = ref->next;
1085         *tail = &ref->next;
1086 }
1087
1088 static struct ref *alloc_delete_ref(void)
1089 {
1090         struct ref *ref = alloc_ref("(delete)");
1091         hashclr(ref->new_sha1);
1092         return ref;
1093 }
1094
1095 static int try_explicit_object_name(const char *name,
1096                                     struct ref **match)
1097 {
1098         unsigned char sha1[20];
1099
1100         if (!*name) {
1101                 if (match)
1102                         *match = alloc_delete_ref();
1103                 return 0;
1104         }
1105
1106         if (get_sha1(name, sha1))
1107                 return -1;
1108
1109         if (match) {
1110                 *match = alloc_ref(name);
1111                 hashcpy((*match)->new_sha1, sha1);
1112         }
1113         return 0;
1114 }
1115
1116 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1117 {
1118         struct ref *ret = alloc_ref(name);
1119         tail_link_ref(ret, tail);
1120         return ret;
1121 }
1122
1123 static char *guess_ref(const char *name, struct ref *peer)
1124 {
1125         struct strbuf buf = STRBUF_INIT;
1126         unsigned char sha1[20];
1127
1128         const char *r = resolve_ref_unsafe(peer->name, sha1, 1, NULL);
1129         if (!r)
1130                 return NULL;
1131
1132         if (starts_with(r, "refs/heads/"))
1133                 strbuf_addstr(&buf, "refs/heads/");
1134         else if (starts_with(r, "refs/tags/"))
1135                 strbuf_addstr(&buf, "refs/tags/");
1136         else
1137                 return NULL;
1138
1139         strbuf_addstr(&buf, name);
1140         return strbuf_detach(&buf, NULL);
1141 }
1142
1143 static int match_explicit_lhs(struct ref *src,
1144                               struct refspec *rs,
1145                               struct ref **match,
1146                               int *allocated_match)
1147 {
1148         switch (count_refspec_match(rs->src, src, match)) {
1149         case 1:
1150                 if (allocated_match)
1151                         *allocated_match = 0;
1152                 return 0;
1153         case 0:
1154                 /* The source could be in the get_sha1() format
1155                  * not a reference name.  :refs/other is a
1156                  * way to delete 'other' ref at the remote end.
1157                  */
1158                 if (try_explicit_object_name(rs->src, match) < 0)
1159                         return error("src refspec %s does not match any.", rs->src);
1160                 if (allocated_match)
1161                         *allocated_match = 1;
1162                 return 0;
1163         default:
1164                 return error("src refspec %s matches more than one.", rs->src);
1165         }
1166 }
1167
1168 static int match_explicit(struct ref *src, struct ref *dst,
1169                           struct ref ***dst_tail,
1170                           struct refspec *rs)
1171 {
1172         struct ref *matched_src, *matched_dst;
1173         int allocated_src = 0;
1174
1175         const char *dst_value = rs->dst;
1176         char *dst_guess;
1177
1178         if (rs->pattern || rs->matching)
1179                 return 0;
1180
1181         matched_src = matched_dst = NULL;
1182         if (match_explicit_lhs(src, rs, &matched_src, &allocated_src) < 0)
1183                 return -1;
1184
1185         if (!dst_value) {
1186                 unsigned char sha1[20];
1187                 int flag;
1188
1189                 dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
1190                 if (!dst_value ||
1191                     ((flag & REF_ISSYMREF) &&
1192                      !starts_with(dst_value, "refs/heads/")))
1193                         die("%s cannot be resolved to branch.",
1194                             matched_src->name);
1195         }
1196
1197         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1198         case 1:
1199                 break;
1200         case 0:
1201                 if (!memcmp(dst_value, "refs/", 5))
1202                         matched_dst = make_linked_ref(dst_value, dst_tail);
1203                 else if (is_null_sha1(matched_src->new_sha1))
1204                         error("unable to delete '%s': remote ref does not exist",
1205                               dst_value);
1206                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1207                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1208                 else
1209                         error("unable to push to unqualified destination: %s\n"
1210                               "The destination refspec neither matches an "
1211                               "existing ref on the remote nor\n"
1212                               "begins with refs/, and we are unable to "
1213                               "guess a prefix based on the source ref.",
1214                               dst_value);
1215                 break;
1216         default:
1217                 matched_dst = NULL;
1218                 error("dst refspec %s matches more than one.",
1219                       dst_value);
1220                 break;
1221         }
1222         if (!matched_dst)
1223                 return -1;
1224         if (matched_dst->peer_ref)
1225                 return error("dst ref %s receives from more than one src.",
1226                       matched_dst->name);
1227         else {
1228                 matched_dst->peer_ref = allocated_src ?
1229                                         matched_src :
1230                                         copy_ref(matched_src);
1231                 matched_dst->force = rs->force;
1232         }
1233         return 0;
1234 }
1235
1236 static int match_explicit_refs(struct ref *src, struct ref *dst,
1237                                struct ref ***dst_tail, struct refspec *rs,
1238                                int rs_nr)
1239 {
1240         int i, errs;
1241         for (i = errs = 0; i < rs_nr; i++)
1242                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1243         return errs;
1244 }
1245
1246 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1247                 int send_mirror, int direction, const struct refspec **ret_pat)
1248 {
1249         const struct refspec *pat;
1250         char *name;
1251         int i;
1252         int matching_refs = -1;
1253         for (i = 0; i < rs_nr; i++) {
1254                 if (rs[i].matching &&
1255                     (matching_refs == -1 || rs[i].force)) {
1256                         matching_refs = i;
1257                         continue;
1258                 }
1259
1260                 if (rs[i].pattern) {
1261                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1262                         int match;
1263                         if (direction == FROM_SRC)
1264                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1265                         else
1266                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1267                         if (match) {
1268                                 matching_refs = i;
1269                                 break;
1270                         }
1271                 }
1272         }
1273         if (matching_refs == -1)
1274                 return NULL;
1275
1276         pat = rs + matching_refs;
1277         if (pat->matching) {
1278                 /*
1279                  * "matching refs"; traditionally we pushed everything
1280                  * including refs outside refs/heads/ hierarchy, but
1281                  * that does not make much sense these days.
1282                  */
1283                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1284                         return NULL;
1285                 name = xstrdup(ref->name);
1286         }
1287         if (ret_pat)
1288                 *ret_pat = pat;
1289         return name;
1290 }
1291
1292 static struct ref **tail_ref(struct ref **head)
1293 {
1294         struct ref **tail = head;
1295         while (*tail)
1296                 tail = &((*tail)->next);
1297         return tail;
1298 }
1299
1300 struct tips {
1301         struct commit **tip;
1302         int nr, alloc;
1303 };
1304
1305 static void add_to_tips(struct tips *tips, const unsigned char *sha1)
1306 {
1307         struct commit *commit;
1308
1309         if (is_null_sha1(sha1))
1310                 return;
1311         commit = lookup_commit_reference_gently(sha1, 1);
1312         if (!commit || (commit->object.flags & TMP_MARK))
1313                 return;
1314         commit->object.flags |= TMP_MARK;
1315         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1316         tips->tip[tips->nr++] = commit;
1317 }
1318
1319 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1320 {
1321         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1322         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1323         struct string_list_item *item;
1324         struct ref *ref;
1325         struct tips sent_tips;
1326
1327         /*
1328          * Collect everything we know they would have at the end of
1329          * this push, and collect all tags they have.
1330          */
1331         memset(&sent_tips, 0, sizeof(sent_tips));
1332         for (ref = *dst; ref; ref = ref->next) {
1333                 if (ref->peer_ref &&
1334                     !is_null_sha1(ref->peer_ref->new_sha1))
1335                         add_to_tips(&sent_tips, ref->peer_ref->new_sha1);
1336                 else
1337                         add_to_tips(&sent_tips, ref->old_sha1);
1338                 if (starts_with(ref->name, "refs/tags/"))
1339                         string_list_append(&dst_tag, ref->name);
1340         }
1341         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1342
1343         sort_string_list(&dst_tag);
1344
1345         /* Collect tags they do not have. */
1346         for (ref = src; ref; ref = ref->next) {
1347                 if (!starts_with(ref->name, "refs/tags/"))
1348                         continue; /* not a tag */
1349                 if (string_list_has_string(&dst_tag, ref->name))
1350                         continue; /* they already have it */
1351                 if (sha1_object_info(ref->new_sha1, NULL) != OBJ_TAG)
1352                         continue; /* be conservative */
1353                 item = string_list_append(&src_tag, ref->name);
1354                 item->util = ref;
1355         }
1356         string_list_clear(&dst_tag, 0);
1357
1358         /*
1359          * At this point, src_tag lists tags that are missing from
1360          * dst, and sent_tips lists the tips we are pushing or those
1361          * that we know they already have. An element in the src_tag
1362          * that is an ancestor of any of the sent_tips needs to be
1363          * sent to the other side.
1364          */
1365         if (sent_tips.nr) {
1366                 for_each_string_list_item(item, &src_tag) {
1367                         struct ref *ref = item->util;
1368                         struct ref *dst_ref;
1369                         struct commit *commit;
1370
1371                         if (is_null_sha1(ref->new_sha1))
1372                                 continue;
1373                         commit = lookup_commit_reference_gently(ref->new_sha1, 1);
1374                         if (!commit)
1375                                 /* not pushing a commit, which is not an error */
1376                                 continue;
1377
1378                         /*
1379                          * Is this tag, which they do not have, reachable from
1380                          * any of the commits we are sending?
1381                          */
1382                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1383                                 continue;
1384
1385                         /* Add it in */
1386                         dst_ref = make_linked_ref(ref->name, dst_tail);
1387                         hashcpy(dst_ref->new_sha1, ref->new_sha1);
1388                         dst_ref->peer_ref = copy_ref(ref);
1389                 }
1390         }
1391         string_list_clear(&src_tag, 0);
1392         free(sent_tips.tip);
1393 }
1394
1395 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1396 {
1397         for ( ; list; list = list->next)
1398                 if (!strcmp(list->name, name))
1399                         return (struct ref *)list;
1400         return NULL;
1401 }
1402
1403 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1404 {
1405         for ( ; ref; ref = ref->next)
1406                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1407
1408         sort_string_list(ref_index);
1409 }
1410
1411 /*
1412  * Given only the set of local refs, sanity-check the set of push
1413  * refspecs. We can't catch all errors that match_push_refs would,
1414  * but we can catch some errors early before even talking to the
1415  * remote side.
1416  */
1417 int check_push_refs(struct ref *src, int nr_refspec, const char **refspec_names)
1418 {
1419         struct refspec *refspec = parse_push_refspec(nr_refspec, refspec_names);
1420         int ret = 0;
1421         int i;
1422
1423         for (i = 0; i < nr_refspec; i++) {
1424                 struct refspec *rs = refspec + i;
1425
1426                 if (rs->pattern || rs->matching)
1427                         continue;
1428
1429                 ret |= match_explicit_lhs(src, rs, NULL, NULL);
1430         }
1431
1432         free_refspec(nr_refspec, refspec);
1433         return ret;
1434 }
1435
1436 /*
1437  * Given the set of refs the local repository has, the set of refs the
1438  * remote repository has, and the refspec used for push, determine
1439  * what remote refs we will update and with what value by setting
1440  * peer_ref (which object is being pushed) and force (if the push is
1441  * forced) in elements of "dst". The function may add new elements to
1442  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1443  */
1444 int match_push_refs(struct ref *src, struct ref **dst,
1445                     int nr_refspec, const char **refspec, int flags)
1446 {
1447         struct refspec *rs;
1448         int send_all = flags & MATCH_REFS_ALL;
1449         int send_mirror = flags & MATCH_REFS_MIRROR;
1450         int send_prune = flags & MATCH_REFS_PRUNE;
1451         int errs;
1452         static const char *default_refspec[] = { ":", NULL };
1453         struct ref *ref, **dst_tail = tail_ref(dst);
1454         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1455
1456         if (!nr_refspec) {
1457                 nr_refspec = 1;
1458                 refspec = default_refspec;
1459         }
1460         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1461         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1462
1463         /* pick the remainder */
1464         for (ref = src; ref; ref = ref->next) {
1465                 struct string_list_item *dst_item;
1466                 struct ref *dst_peer;
1467                 const struct refspec *pat = NULL;
1468                 char *dst_name;
1469
1470                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1471                 if (!dst_name)
1472                         continue;
1473
1474                 if (!dst_ref_index.nr)
1475                         prepare_ref_index(&dst_ref_index, *dst);
1476
1477                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1478                 dst_peer = dst_item ? dst_item->util : NULL;
1479                 if (dst_peer) {
1480                         if (dst_peer->peer_ref)
1481                                 /* We're already sending something to this ref. */
1482                                 goto free_name;
1483                 } else {
1484                         if (pat->matching && !(send_all || send_mirror))
1485                                 /*
1486                                  * Remote doesn't have it, and we have no
1487                                  * explicit pattern, and we don't have
1488                                  * --all or --mirror.
1489                                  */
1490                                 goto free_name;
1491
1492                         /* Create a new one and link it */
1493                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1494                         hashcpy(dst_peer->new_sha1, ref->new_sha1);
1495                         string_list_insert(&dst_ref_index,
1496                                 dst_peer->name)->util = dst_peer;
1497                 }
1498                 dst_peer->peer_ref = copy_ref(ref);
1499                 dst_peer->force = pat->force;
1500         free_name:
1501                 free(dst_name);
1502         }
1503
1504         string_list_clear(&dst_ref_index, 0);
1505
1506         if (flags & MATCH_REFS_FOLLOW_TAGS)
1507                 add_missing_tags(src, dst, &dst_tail);
1508
1509         if (send_prune) {
1510                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1511                 /* check for missing refs on the remote */
1512                 for (ref = *dst; ref; ref = ref->next) {
1513                         char *src_name;
1514
1515                         if (ref->peer_ref)
1516                                 /* We're already sending something to this ref. */
1517                                 continue;
1518
1519                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1520                         if (src_name) {
1521                                 if (!src_ref_index.nr)
1522                                         prepare_ref_index(&src_ref_index, src);
1523                                 if (!string_list_has_string(&src_ref_index,
1524                                             src_name))
1525                                         ref->peer_ref = alloc_delete_ref();
1526                                 free(src_name);
1527                         }
1528                 }
1529                 string_list_clear(&src_ref_index, 0);
1530         }
1531         if (errs)
1532                 return -1;
1533         return 0;
1534 }
1535
1536 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1537                              int force_update)
1538 {
1539         struct ref *ref;
1540
1541         for (ref = remote_refs; ref; ref = ref->next) {
1542                 int force_ref_update = ref->force || force_update;
1543                 int reject_reason = 0;
1544
1545                 if (ref->peer_ref)
1546                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1547                 else if (!send_mirror)
1548                         continue;
1549
1550                 ref->deletion = is_null_sha1(ref->new_sha1);
1551                 if (!ref->deletion &&
1552                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1553                         ref->status = REF_STATUS_UPTODATE;
1554                         continue;
1555                 }
1556
1557                 /*
1558                  * Bypass the usual "must fast-forward" check but
1559                  * replace it with a weaker "the old value must be
1560                  * this value we observed".  If the remote ref has
1561                  * moved and is now different from what we expect,
1562                  * reject any push.
1563                  *
1564                  * It also is an error if the user told us to check
1565                  * with the remote-tracking branch to find the value
1566                  * to expect, but we did not have such a tracking
1567                  * branch.
1568                  */
1569                 if (ref->expect_old_sha1) {
1570                         if (ref->expect_old_no_trackback ||
1571                             hashcmp(ref->old_sha1, ref->old_sha1_expect))
1572                                 reject_reason = REF_STATUS_REJECT_STALE;
1573                 }
1574
1575                 /*
1576                  * The usual "must fast-forward" rules.
1577                  *
1578                  * Decide whether an individual refspec A:B can be
1579                  * pushed.  The push will succeed if any of the
1580                  * following are true:
1581                  *
1582                  * (1) the remote reference B does not exist
1583                  *
1584                  * (2) the remote reference B is being removed (i.e.,
1585                  *     pushing :B where no source is specified)
1586                  *
1587                  * (3) the destination is not under refs/tags/, and
1588                  *     if the old and new value is a commit, the new
1589                  *     is a descendant of the old.
1590                  *
1591                  * (4) it is forced using the +A:B notation, or by
1592                  *     passing the --force argument
1593                  */
1594
1595                 else if (!ref->deletion && !is_null_sha1(ref->old_sha1)) {
1596                         if (starts_with(ref->name, "refs/tags/"))
1597                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1598                         else if (!has_sha1_file(ref->old_sha1))
1599                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1600                         else if (!lookup_commit_reference_gently(ref->old_sha1, 1) ||
1601                                  !lookup_commit_reference_gently(ref->new_sha1, 1))
1602                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1603                         else if (!ref_newer(ref->new_sha1, ref->old_sha1))
1604                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1605                 }
1606
1607                 /*
1608                  * "--force" will defeat any rejection implemented
1609                  * by the rules above.
1610                  */
1611                 if (!force_ref_update)
1612                         ref->status = reject_reason;
1613                 else if (reject_reason)
1614                         ref->forced_update = 1;
1615         }
1616 }
1617
1618 struct branch *branch_get(const char *name)
1619 {
1620         struct branch *ret;
1621
1622         read_config();
1623         if (!name || !*name || !strcmp(name, "HEAD"))
1624                 ret = current_branch;
1625         else
1626                 ret = make_branch(name, 0);
1627         if (ret && ret->remote_name) {
1628                 ret->remote = remote_get(ret->remote_name);
1629                 if (ret->merge_nr) {
1630                         int i;
1631                         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1632                         for (i = 0; i < ret->merge_nr; i++) {
1633                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1634                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1635                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1636                                     && !strcmp(ret->remote_name, "."))
1637                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1638                         }
1639                 }
1640         }
1641         if (ret && ret->pushremote_name && ret->push_name) {
1642                 struct remote *pushremote;
1643                 pushremote = pushremote_get(ret->pushremote_name);
1644                 ret->push.src = xstrdup(ret->push_name);
1645                 if (remote_find_tracking(pushremote, &ret->push)
1646                     && !strcmp(ret->pushremote_name, "."))
1647                         ret->push.dst = xstrdup(ret->push_name);
1648         }
1649         return ret;
1650 }
1651
1652 int branch_has_merge_config(struct branch *branch)
1653 {
1654         return branch && !!branch->merge;
1655 }
1656
1657 int branch_merge_matches(struct branch *branch,
1658                                  int i,
1659                                  const char *refname)
1660 {
1661         if (!branch || i < 0 || i >= branch->merge_nr)
1662                 return 0;
1663         return refname_match(branch->merge[i]->src, refname);
1664 }
1665
1666 static int ignore_symref_update(const char *refname)
1667 {
1668         unsigned char sha1[20];
1669         int flag;
1670
1671         if (!resolve_ref_unsafe(refname, sha1, 0, &flag))
1672                 return 0; /* non-existing refs are OK */
1673         return (flag & REF_ISSYMREF);
1674 }
1675
1676 /*
1677  * Create and return a list of (struct ref) consisting of copies of
1678  * each remote_ref that matches refspec.  refspec must be a pattern.
1679  * Fill in the copies' peer_ref to describe the local tracking refs to
1680  * which they map.  Omit any references that would map to an existing
1681  * local symbolic ref.
1682  */
1683 static struct ref *get_expanded_map(const struct ref *remote_refs,
1684                                     const struct refspec *refspec)
1685 {
1686         const struct ref *ref;
1687         struct ref *ret = NULL;
1688         struct ref **tail = &ret;
1689
1690         for (ref = remote_refs; ref; ref = ref->next) {
1691                 char *expn_name = NULL;
1692
1693                 if (strchr(ref->name, '^'))
1694                         continue; /* a dereference item */
1695                 if (match_name_with_pattern(refspec->src, ref->name,
1696                                             refspec->dst, &expn_name) &&
1697                     !ignore_symref_update(expn_name)) {
1698                         struct ref *cpy = copy_ref(ref);
1699
1700                         cpy->peer_ref = alloc_ref(expn_name);
1701                         if (refspec->force)
1702                                 cpy->peer_ref->force = 1;
1703                         *tail = cpy;
1704                         tail = &cpy->next;
1705                 }
1706                 free(expn_name);
1707         }
1708
1709         return ret;
1710 }
1711
1712 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1713 {
1714         const struct ref *ref;
1715         for (ref = refs; ref; ref = ref->next) {
1716                 if (refname_match(name, ref->name))
1717                         return ref;
1718         }
1719         return NULL;
1720 }
1721
1722 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1723 {
1724         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1725
1726         if (!ref)
1727                 return NULL;
1728
1729         return copy_ref(ref);
1730 }
1731
1732 static struct ref *get_local_ref(const char *name)
1733 {
1734         if (!name || name[0] == '\0')
1735                 return NULL;
1736
1737         if (starts_with(name, "refs/"))
1738                 return alloc_ref(name);
1739
1740         if (starts_with(name, "heads/") ||
1741             starts_with(name, "tags/") ||
1742             starts_with(name, "remotes/"))
1743                 return alloc_ref_with_prefix("refs/", 5, name);
1744
1745         return alloc_ref_with_prefix("refs/heads/", 11, name);
1746 }
1747
1748 int get_fetch_map(const struct ref *remote_refs,
1749                   const struct refspec *refspec,
1750                   struct ref ***tail,
1751                   int missing_ok)
1752 {
1753         struct ref *ref_map, **rmp;
1754
1755         if (refspec->pattern) {
1756                 ref_map = get_expanded_map(remote_refs, refspec);
1757         } else {
1758                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1759
1760                 if (refspec->exact_sha1) {
1761                         ref_map = alloc_ref(name);
1762                         get_sha1_hex(name, ref_map->old_sha1);
1763                 } else {
1764                         ref_map = get_remote_ref(remote_refs, name);
1765                 }
1766                 if (!missing_ok && !ref_map)
1767                         die("Couldn't find remote ref %s", name);
1768                 if (ref_map) {
1769                         ref_map->peer_ref = get_local_ref(refspec->dst);
1770                         if (ref_map->peer_ref && refspec->force)
1771                                 ref_map->peer_ref->force = 1;
1772                 }
1773         }
1774
1775         for (rmp = &ref_map; *rmp; ) {
1776                 if ((*rmp)->peer_ref) {
1777                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1778                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1779                                 struct ref *ignore = *rmp;
1780                                 error("* Ignoring funny ref '%s' locally",
1781                                       (*rmp)->peer_ref->name);
1782                                 *rmp = (*rmp)->next;
1783                                 free(ignore->peer_ref);
1784                                 free(ignore);
1785                                 continue;
1786                         }
1787                 }
1788                 rmp = &((*rmp)->next);
1789         }
1790
1791         if (ref_map)
1792                 tail_link_ref(ref_map, tail);
1793
1794         return 0;
1795 }
1796
1797 int resolve_remote_symref(struct ref *ref, struct ref *list)
1798 {
1799         if (!ref->symref)
1800                 return 0;
1801         for (; list; list = list->next)
1802                 if (!strcmp(ref->symref, list->name)) {
1803                         hashcpy(ref->old_sha1, list->old_sha1);
1804                         return 0;
1805                 }
1806         return 1;
1807 }
1808
1809 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1810 {
1811         while (list) {
1812                 struct commit_list *temp = list;
1813                 temp->item->object.flags &= ~mark;
1814                 list = temp->next;
1815                 free(temp);
1816         }
1817 }
1818
1819 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1820 {
1821         struct object *o;
1822         struct commit *old, *new;
1823         struct commit_list *list, *used;
1824         int found = 0;
1825
1826         /*
1827          * Both new and old must be commit-ish and new is descendant of
1828          * old.  Otherwise we require --force.
1829          */
1830         o = deref_tag(parse_object(old_sha1), NULL, 0);
1831         if (!o || o->type != OBJ_COMMIT)
1832                 return 0;
1833         old = (struct commit *) o;
1834
1835         o = deref_tag(parse_object(new_sha1), NULL, 0);
1836         if (!o || o->type != OBJ_COMMIT)
1837                 return 0;
1838         new = (struct commit *) o;
1839
1840         if (parse_commit(new) < 0)
1841                 return 0;
1842
1843         used = list = NULL;
1844         commit_list_insert(new, &list);
1845         while (list) {
1846                 new = pop_most_recent_commit(&list, TMP_MARK);
1847                 commit_list_insert(new, &used);
1848                 if (new == old) {
1849                         found = 1;
1850                         break;
1851                 }
1852         }
1853         unmark_and_free(list, TMP_MARK);
1854         unmark_and_free(used, TMP_MARK);
1855         return found;
1856 }
1857
1858 /*
1859  * Compare a branch with its upstream, and save their differences (number
1860  * of commits) in *num_ours and *num_theirs.
1861  *
1862  * Return 0 if branch has no upstream (no base), -1 if upstream is missing
1863  * (with "gone" base), otherwise 1 (with base).
1864  */
1865 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1866 {
1867         unsigned char sha1[20];
1868         struct commit *ours, *theirs;
1869         char symmetric[84];
1870         struct rev_info revs;
1871         const char *rev_argv[10], *base;
1872         int rev_argc;
1873
1874         /* Cannot stat unless we are marked to build on top of somebody else. */
1875         if (!branch ||
1876             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1877                 return 0;
1878
1879         /* Cannot stat if what we used to build on no longer exists */
1880         base = branch->merge[0]->dst;
1881         if (read_ref(base, sha1))
1882                 return -1;
1883         theirs = lookup_commit_reference(sha1);
1884         if (!theirs)
1885                 return -1;
1886
1887         if (read_ref(branch->refname, sha1))
1888                 return -1;
1889         ours = lookup_commit_reference(sha1);
1890         if (!ours)
1891                 return -1;
1892
1893         /* are we the same? */
1894         if (theirs == ours) {
1895                 *num_theirs = *num_ours = 0;
1896                 return 1;
1897         }
1898
1899         /* Run "rev-list --left-right ours...theirs" internally... */
1900         rev_argc = 0;
1901         rev_argv[rev_argc++] = NULL;
1902         rev_argv[rev_argc++] = "--left-right";
1903         rev_argv[rev_argc++] = symmetric;
1904         rev_argv[rev_argc++] = "--";
1905         rev_argv[rev_argc] = NULL;
1906
1907         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1908         strcpy(symmetric + 40, "...");
1909         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1910
1911         init_revisions(&revs, NULL);
1912         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1913         prepare_revision_walk(&revs);
1914
1915         /* ... and count the commits on each side. */
1916         *num_ours = 0;
1917         *num_theirs = 0;
1918         while (1) {
1919                 struct commit *c = get_revision(&revs);
1920                 if (!c)
1921                         break;
1922                 if (c->object.flags & SYMMETRIC_LEFT)
1923                         (*num_ours)++;
1924                 else
1925                         (*num_theirs)++;
1926         }
1927
1928         /* clear object flags smudged by the above traversal */
1929         clear_commit_marks(ours, ALL_REV_FLAGS);
1930         clear_commit_marks(theirs, ALL_REV_FLAGS);
1931         return 1;
1932 }
1933
1934 /*
1935  * Return true when there is anything to report, otherwise false.
1936  */
1937 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1938 {
1939         int ours, theirs;
1940         const char *base;
1941         int upstream_is_gone = 0;
1942
1943         switch (stat_tracking_info(branch, &ours, &theirs)) {
1944         case 0:
1945                 /* no base */
1946                 return 0;
1947         case -1:
1948                 /* with "gone" base */
1949                 upstream_is_gone = 1;
1950                 break;
1951         default:
1952                 /* with base */
1953                 break;
1954         }
1955
1956         base = branch->merge[0]->dst;
1957         base = shorten_unambiguous_ref(base, 0);
1958         if (upstream_is_gone) {
1959                 strbuf_addf(sb,
1960                         _("Your branch is based on '%s', but the upstream is gone.\n"),
1961                         base);
1962                 if (advice_status_hints)
1963                         strbuf_addf(sb,
1964                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
1965         } else if (!ours && !theirs) {
1966                 strbuf_addf(sb,
1967                         _("Your branch is up-to-date with '%s'.\n"),
1968                         base);
1969         } else if (!theirs) {
1970                 strbuf_addf(sb,
1971                         Q_("Your branch is ahead of '%s' by %d commit.\n",
1972                            "Your branch is ahead of '%s' by %d commits.\n",
1973                            ours),
1974                         base, ours);
1975                 if (advice_status_hints && !branch->push.dst)
1976                         strbuf_addf(sb,
1977                                 _("  (use \"git push\" to publish your local commits)\n"));
1978         } else if (!ours) {
1979                 strbuf_addf(sb,
1980                         Q_("Your branch is behind '%s' by %d commit, "
1981                                "and can be fast-forwarded.\n",
1982                            "Your branch is behind '%s' by %d commits, "
1983                                "and can be fast-forwarded.\n",
1984                            theirs),
1985                         base, theirs);
1986                 if (advice_status_hints)
1987                         strbuf_addf(sb,
1988                                 _("  (use \"git pull\" to update your local branch)\n"));
1989         } else {
1990                 strbuf_addf(sb,
1991                         Q_("Your branch and '%s' have diverged,\n"
1992                                "and have %d and %d different commit each, "
1993                                "respectively.\n",
1994                            "Your branch and '%s' have diverged,\n"
1995                                "and have %d and %d different commits each, "
1996                                "respectively.\n",
1997                            theirs),
1998                         base, ours, theirs);
1999                 if (advice_status_hints)
2000                         strbuf_addf(sb,
2001                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
2002         }
2003         if (branch->push.dst) {
2004                 unsigned char local_sha1[20];
2005                 unsigned char remote_sha1[20];
2006                 const char *pub;
2007
2008                 pub = shorten_unambiguous_ref(branch->push.dst, 0);
2009
2010                 /* Is it published? */
2011                 if (!read_ref(branch->refname, local_sha1) &&
2012                                 !read_ref(branch->push.dst, remote_sha1)) {
2013                         if (hashcmp(local_sha1, remote_sha1)) {
2014                                 strbuf_addf(sb, _("Some commits haven't been published to '%s'.\n"), pub);
2015                                 if (advice_status_hints)
2016                                         strbuf_addf(sb, _("  (use \"git push\" to publish your local commits)\n"));
2017                         }
2018                 }
2019         }
2020         return 1;
2021 }
2022
2023 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
2024 {
2025         struct ref ***local_tail = cb_data;
2026         struct ref *ref;
2027         int len;
2028
2029         /* we already know it starts with refs/ to get here */
2030         if (check_refname_format(refname + 5, 0))
2031                 return 0;
2032
2033         len = strlen(refname) + 1;
2034         ref = xcalloc(1, sizeof(*ref) + len);
2035         hashcpy(ref->new_sha1, sha1);
2036         memcpy(ref->name, refname, len);
2037         **local_tail = ref;
2038         *local_tail = &ref->next;
2039         return 0;
2040 }
2041
2042 struct ref *get_local_heads(void)
2043 {
2044         struct ref *local_refs = NULL, **local_tail = &local_refs;
2045         for_each_ref(one_local_ref, &local_tail);
2046         return local_refs;
2047 }
2048
2049 struct ref *guess_remote_head(const struct ref *head,
2050                               const struct ref *refs,
2051                               int all)
2052 {
2053         const struct ref *r;
2054         struct ref *list = NULL;
2055         struct ref **tail = &list;
2056
2057         if (!head)
2058                 return NULL;
2059
2060         /*
2061          * Some transports support directly peeking at
2062          * where HEAD points; if that is the case, then
2063          * we don't have to guess.
2064          */
2065         if (head->symref)
2066                 return copy_ref(find_ref_by_name(refs, head->symref));
2067
2068         /* If refs/heads/master could be right, it is. */
2069         if (!all) {
2070                 r = find_ref_by_name(refs, "refs/heads/master");
2071                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
2072                         return copy_ref(r);
2073         }
2074
2075         /* Look for another ref that points there */
2076         for (r = refs; r; r = r->next) {
2077                 if (r != head &&
2078                     starts_with(r->name, "refs/heads/") &&
2079                     !hashcmp(r->old_sha1, head->old_sha1)) {
2080                         *tail = copy_ref(r);
2081                         tail = &((*tail)->next);
2082                         if (!all)
2083                                 break;
2084                 }
2085         }
2086
2087         return list;
2088 }
2089
2090 struct stale_heads_info {
2091         struct string_list *ref_names;
2092         struct ref **stale_refs_tail;
2093         struct refspec *refs;
2094         int ref_count;
2095 };
2096
2097 static int get_stale_heads_cb(const char *refname,
2098         const unsigned char *sha1, int flags, void *cb_data)
2099 {
2100         struct stale_heads_info *info = cb_data;
2101         struct string_list matches = STRING_LIST_INIT_DUP;
2102         struct refspec query;
2103         int i, stale = 1;
2104         memset(&query, 0, sizeof(struct refspec));
2105         query.dst = (char *)refname;
2106
2107         query_refspecs_multiple(info->refs, info->ref_count, &query, &matches);
2108         if (matches.nr == 0)
2109                 goto clean_exit; /* No matches */
2110
2111         /*
2112          * If we did find a suitable refspec and it's not a symref and
2113          * it's not in the list of refs that currently exist in that
2114          * remote, we consider it to be stale. In order to deal with
2115          * overlapping refspecs, we need to go over all of the
2116          * matching refs.
2117          */
2118         if (flags & REF_ISSYMREF)
2119                 goto clean_exit;
2120
2121         for (i = 0; stale && i < matches.nr; i++)
2122                 if (string_list_has_string(info->ref_names, matches.items[i].string))
2123                         stale = 0;
2124
2125         if (stale) {
2126                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2127                 hashcpy(ref->new_sha1, sha1);
2128         }
2129
2130 clean_exit:
2131         string_list_clear(&matches, 0);
2132         return 0;
2133 }
2134
2135 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
2136 {
2137         struct ref *ref, *stale_refs = NULL;
2138         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2139         struct stale_heads_info info;
2140         info.ref_names = &ref_names;
2141         info.stale_refs_tail = &stale_refs;
2142         info.refs = refs;
2143         info.ref_count = ref_count;
2144         for (ref = fetch_map; ref; ref = ref->next)
2145                 string_list_append(&ref_names, ref->name);
2146         sort_string_list(&ref_names);
2147         for_each_ref(get_stale_heads_cb, &info);
2148         string_list_clear(&ref_names, 0);
2149         return stale_refs;
2150 }
2151
2152 /*
2153  * Compare-and-swap
2154  */
2155 void clear_cas_option(struct push_cas_option *cas)
2156 {
2157         int i;
2158
2159         for (i = 0; i < cas->nr; i++)
2160                 free(cas->entry[i].refname);
2161         free(cas->entry);
2162         memset(cas, 0, sizeof(*cas));
2163 }
2164
2165 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2166                                       const char *refname,
2167                                       size_t refnamelen)
2168 {
2169         struct push_cas *entry;
2170         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2171         entry = &cas->entry[cas->nr++];
2172         memset(entry, 0, sizeof(*entry));
2173         entry->refname = xmemdupz(refname, refnamelen);
2174         return entry;
2175 }
2176
2177 int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2178 {
2179         const char *colon;
2180         struct push_cas *entry;
2181
2182         if (unset) {
2183                 /* "--no-<option>" */
2184                 clear_cas_option(cas);
2185                 return 0;
2186         }
2187
2188         if (!arg) {
2189                 /* just "--<option>" */
2190                 cas->use_tracking_for_rest = 1;
2191                 return 0;
2192         }
2193
2194         /* "--<option>=refname" or "--<option>=refname:value" */
2195         colon = strchrnul(arg, ':');
2196         entry = add_cas_entry(cas, arg, colon - arg);
2197         if (!*colon)
2198                 entry->use_tracking = 1;
2199         else if (get_sha1(colon + 1, entry->expect))
2200                 return error("cannot parse expected object name '%s'", colon + 1);
2201         return 0;
2202 }
2203
2204 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2205 {
2206         return parse_push_cas_option(opt->value, arg, unset);
2207 }
2208
2209 int is_empty_cas(const struct push_cas_option *cas)
2210 {
2211         return !cas->use_tracking_for_rest && !cas->nr;
2212 }
2213
2214 /*
2215  * Look at remote.fetch refspec and see if we have a remote
2216  * tracking branch for the refname there.  Fill its current
2217  * value in sha1[].
2218  * If we cannot do so, return negative to signal an error.
2219  */
2220 static int remote_tracking(struct remote *remote, const char *refname,
2221                            unsigned char sha1[20])
2222 {
2223         char *dst;
2224
2225         dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
2226         if (!dst)
2227                 return -1; /* no tracking ref for refname at remote */
2228         if (read_ref(dst, sha1))
2229                 return -1; /* we know what the tracking ref is but we cannot read it */
2230         return 0;
2231 }
2232
2233 static void apply_cas(struct push_cas_option *cas,
2234                       struct remote *remote,
2235                       struct ref *ref)
2236 {
2237         int i;
2238
2239         /* Find an explicit --<option>=<name>[:<value>] entry */
2240         for (i = 0; i < cas->nr; i++) {
2241                 struct push_cas *entry = &cas->entry[i];
2242                 if (!refname_match(entry->refname, ref->name))
2243                         continue;
2244                 ref->expect_old_sha1 = 1;
2245                 if (!entry->use_tracking)
2246                         hashcpy(ref->old_sha1_expect, cas->entry[i].expect);
2247                 else if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2248                         ref->expect_old_no_trackback = 1;
2249                 return;
2250         }
2251
2252         /* Are we using "--<option>" to cover all? */
2253         if (!cas->use_tracking_for_rest)
2254                 return;
2255
2256         ref->expect_old_sha1 = 1;
2257         if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2258                 ref->expect_old_no_trackback = 1;
2259 }
2260
2261 void apply_push_cas(struct push_cas_option *cas,
2262                     struct remote *remote,
2263                     struct ref *remote_refs)
2264 {
2265         struct ref *ref;
2266         for (ref = remote_refs; ref; ref = ref->next)
2267                 apply_cas(cas, remote, ref);
2268 }