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 int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
 861 {
 862         int i;
 863         int find_src = !query->src;
 864         const char *needle = find_src ? query->dst : query->src;
 865         char **result = find_src ? &query->src : &query->dst;
 866
 867         if (find_src && !query->dst)
 868                 return error("query_refspecs: need either src or dst");
 869
 870         for (i = 0; i < ref_count; i++) {
 871                 struct refspec *refspec = &refs[i];
 872                 const char *key = find_src ? refspec->dst : refspec->src;
 873                 const char *value = find_src ? refspec->src : refspec->dst;
 874
 875                 if (!refspec->dst)
 876                         continue;
 877                 if (refspec->pattern) {
 878                         if (match_name_with_pattern(key, needle, value, result)) {
 879                                 query->force = refspec->force;
 880                                 return 0;
 881                         }
 882                 } else if (!strcmp(needle, key)) {
 883                         *result = xstrdup(value);
 884                         query->force = refspec->force;
 885                         return 0;
 886                 }
 887         }
 888         return -1;
 889 }
 890
 891 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 892                      const char *name)
 893 {
 894         struct refspec query;
 895
 896         memset(&query, 0, sizeof(struct refspec));
 897         query.src = (char *)name;
 898
 899         if (query_refspecs(refspecs, nr_refspec, &query))
 900                 return NULL;
 901
 902         return query.dst;
 903 }
 904
 905 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 906 {
 907         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
 908 }
 909
 910 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 911                 const char *name)
 912 {
 913         size_t len = strlen(name);
 914         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 915         memcpy(ref->name, prefix, prefixlen);
 916         memcpy(ref->name + prefixlen, name, len);
 917         return ref;
 918 }
 919
 920 struct ref *alloc_ref(const char *name)
 921 {
 922         return alloc_ref_with_prefix("", 0, name);
 923 }
 924
 925 struct ref *copy_ref(const struct ref *ref)
 926 {
 927         struct ref *cpy;
 928         size_t len;
 929         if (!ref)
 930                 return NULL;
 931         len = strlen(ref->name);
 932         cpy = xmalloc(sizeof(struct ref) + len + 1);
 933         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 934         cpy->next = NULL;
 935         cpy->symref = ref->symref ? xstrdup(ref->symref) : NULL;
 936         cpy->remote_status = ref->remote_status ? xstrdup(ref->remote_status) : NULL;
 937         cpy->peer_ref = copy_ref(ref->peer_ref);
 938         return cpy;
 939 }
 940
 941 struct ref *copy_ref_list(const struct ref *ref)
 942 {
 943         struct ref *ret = NULL;
 944         struct ref **tail = &ret;
 945         while (ref) {
 946                 *tail = copy_ref(ref);
 947                 ref = ref->next;
 948                 tail = &((*tail)->next);
 949         }
 950         return ret;
 951 }
 952
 953 static void free_ref(struct ref *ref)
 954 {
 955         if (!ref)
 956                 return;
 957         free_ref(ref->peer_ref);
 958         free(ref->remote_status);
 959         free(ref->symref);
 960         free(ref);
 961 }
 962
 963 void free_refs(struct ref *ref)
 964 {
 965         struct ref *next;
 966         while (ref) {
 967                 next = ref->next;
 968                 free_ref(ref);
 969                 ref = next;
 970         }
 971 }
 972
 973 int ref_compare_name(const void *va, const void *vb)
 974 {
 975         const struct ref *a = va, *b = vb;
 976         return strcmp(a->name, b->name);
 977 }
 978
 979 static void *ref_list_get_next(const void *a)
 980 {
 981         return ((const struct ref *)a)->next;
 982 }
 983
 984 static void ref_list_set_next(void *a, void *next)
 985 {
 986         ((struct ref *)a)->next = next;
 987 }
 988
 989 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
 990 {
 991         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
 992 }
 993
 994 int count_refspec_match(const char *pattern,
 995                         struct ref *refs,
 996                         struct ref **matched_ref)
 997 {
 998         int patlen = strlen(pattern);
 999         struct ref *matched_weak = NULL;
1000         struct ref *matched = NULL;
1001         int weak_match = 0;
1002         int match = 0;
1003
1004         for (weak_match = match = 0; refs; refs = refs->next) {
1005                 char *name = refs->name;
1006                 int namelen = strlen(name);
1007
1008                 if (!refname_match(pattern, name))
1009                         continue;
1010
1011                 /* A match is "weak" if it is with refs outside
1012                  * heads or tags, and did not specify the pattern
1013                  * in full (e.g. "refs/remotes/origin/master") or at
1014                  * least from the toplevel (e.g. "remotes/origin/master");
1015                  * otherwise "git push $URL master" would result in
1016                  * ambiguity between remotes/origin/master and heads/master
1017                  * at the remote site.
1018                  */
1019                 if (namelen != patlen &&
1020                     patlen != namelen - 5 &&
1021                     !starts_with(name, "refs/heads/") &&
1022                     !starts_with(name, "refs/tags/")) {
1023                         /* We want to catch the case where only weak
1024                          * matches are found and there are multiple
1025                          * matches, and where more than one strong
1026                          * matches are found, as ambiguous.  One
1027                          * strong match with zero or more weak matches
1028                          * are acceptable as a unique match.
1029                          */
1030                         matched_weak = refs;
1031                         weak_match++;
1032                 }
1033                 else {
1034                         matched = refs;
1035                         match++;
1036                 }
1037         }
1038         if (!matched) {
1039                 if (matched_ref)
1040                         *matched_ref = matched_weak;
1041                 return weak_match;
1042         }
1043         else {
1044                 if (matched_ref)
1045                         *matched_ref = matched;
1046                 return match;
1047         }
1048 }
1049
1050 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1051 {
1052         **tail = ref;
1053         while (ref->next)
1054                 ref = ref->next;
1055         *tail = &ref->next;
1056 }
1057
1058 static struct ref *alloc_delete_ref(void)
1059 {
1060         struct ref *ref = alloc_ref("(delete)");
1061         hashclr(ref->new_sha1);
1062         return ref;
1063 }
1064
1065 static int try_explicit_object_name(const char *name,
1066                                     struct ref **match)
1067 {
1068         unsigned char sha1[20];
1069
1070         if (!*name) {
1071                 if (match)
1072                         *match = alloc_delete_ref();
1073                 return 0;
1074         }
1075
1076         if (get_sha1(name, sha1))
1077                 return -1;
1078
1079         if (match) {
1080                 *match = alloc_ref(name);
1081                 hashcpy((*match)->new_sha1, sha1);
1082         }
1083         return 0;
1084 }
1085
1086 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1087 {
1088         struct ref *ret = alloc_ref(name);
1089         tail_link_ref(ret, tail);
1090         return ret;
1091 }
1092
1093 static char *guess_ref(const char *name, struct ref *peer)
1094 {
1095         struct strbuf buf = STRBUF_INIT;
1096         unsigned char sha1[20];
1097
1098         const char *r = resolve_ref_unsafe(peer->name, sha1, 1, NULL);
1099         if (!r)
1100                 return NULL;
1101
1102         if (starts_with(r, "refs/heads/"))
1103                 strbuf_addstr(&buf, "refs/heads/");
1104         else if (starts_with(r, "refs/tags/"))
1105                 strbuf_addstr(&buf, "refs/tags/");
1106         else
1107                 return NULL;
1108
1109         strbuf_addstr(&buf, name);
1110         return strbuf_detach(&buf, NULL);
1111 }
1112
1113 static int match_explicit_lhs(struct ref *src,
1114                               struct refspec *rs,
1115                               struct ref **match,
1116                               int *allocated_match)
1117 {
1118         switch (count_refspec_match(rs->src, src, match)) {
1119         case 1:
1120                 if (allocated_match)
1121                         *allocated_match = 0;
1122                 return 0;
1123         case 0:
1124                 /* The source could be in the get_sha1() format
1125                  * not a reference name.  :refs/other is a
1126                  * way to delete 'other' ref at the remote end.
1127                  */
1128                 if (try_explicit_object_name(rs->src, match) < 0)
1129                         return error("src refspec %s does not match any.", rs->src);
1130                 if (allocated_match)
1131                         *allocated_match = 1;
1132                 return 0;
1133         default:
1134                 return error("src refspec %s matches more than one.", rs->src);
1135         }
1136 }
1137
1138 static int match_explicit(struct ref *src, struct ref *dst,
1139                           struct ref ***dst_tail,
1140                           struct refspec *rs)
1141 {
1142         struct ref *matched_src, *matched_dst;
1143         int allocated_src;
1144
1145         const char *dst_value = rs->dst;
1146         char *dst_guess;
1147
1148         if (rs->pattern || rs->matching)
1149                 return 0;
1150
1151         matched_src = matched_dst = NULL;
1152         if (match_explicit_lhs(src, rs, &matched_src, &allocated_src) < 0)
1153                 return -1;
1154
1155         if (!dst_value) {
1156                 unsigned char sha1[20];
1157                 int flag;
1158
1159                 dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
1160                 if (!dst_value ||
1161                     ((flag & REF_ISSYMREF) &&
1162                      !starts_with(dst_value, "refs/heads/")))
1163                         die("%s cannot be resolved to branch.",
1164                             matched_src->name);
1165         }
1166
1167         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1168         case 1:
1169                 break;
1170         case 0:
1171                 if (!memcmp(dst_value, "refs/", 5))
1172                         matched_dst = make_linked_ref(dst_value, dst_tail);
1173                 else if (is_null_sha1(matched_src->new_sha1))
1174                         error("unable to delete '%s': remote ref does not exist",
1175                               dst_value);
1176                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1177                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1178                 else
1179                         error("unable to push to unqualified destination: %s\n"
1180                               "The destination refspec neither matches an "
1181                               "existing ref on the remote nor\n"
1182                               "begins with refs/, and we are unable to "
1183                               "guess a prefix based on the source ref.",
1184                               dst_value);
1185                 break;
1186         default:
1187                 matched_dst = NULL;
1188                 error("dst refspec %s matches more than one.",
1189                       dst_value);
1190                 break;
1191         }
1192         if (!matched_dst)
1193                 return -1;
1194         if (matched_dst->peer_ref)
1195                 return error("dst ref %s receives from more than one src.",
1196                       matched_dst->name);
1197         else {
1198                 matched_dst->peer_ref = allocated_src ?
1199                                         matched_src :
1200                                         copy_ref(matched_src);
1201                 matched_dst->force = rs->force;
1202         }
1203         return 0;
1204 }
1205
1206 static int match_explicit_refs(struct ref *src, struct ref *dst,
1207                                struct ref ***dst_tail, struct refspec *rs,
1208                                int rs_nr)
1209 {
1210         int i, errs;
1211         for (i = errs = 0; i < rs_nr; i++)
1212                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1213         return errs;
1214 }
1215
1216 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1217                 int send_mirror, int direction, const struct refspec **ret_pat)
1218 {
1219         const struct refspec *pat;
1220         char *name;
1221         int i;
1222         int matching_refs = -1;
1223         for (i = 0; i < rs_nr; i++) {
1224                 if (rs[i].matching &&
1225                     (matching_refs == -1 || rs[i].force)) {
1226                         matching_refs = i;
1227                         continue;
1228                 }
1229
1230                 if (rs[i].pattern) {
1231                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1232                         int match;
1233                         if (direction == FROM_SRC)
1234                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1235                         else
1236                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1237                         if (match) {
1238                                 matching_refs = i;
1239                                 break;
1240                         }
1241                 }
1242         }
1243         if (matching_refs == -1)
1244                 return NULL;
1245
1246         pat = rs + matching_refs;
1247         if (pat->matching) {
1248                 /*
1249                  * "matching refs"; traditionally we pushed everything
1250                  * including refs outside refs/heads/ hierarchy, but
1251                  * that does not make much sense these days.
1252                  */
1253                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1254                         return NULL;
1255                 name = xstrdup(ref->name);
1256         }
1257         if (ret_pat)
1258                 *ret_pat = pat;
1259         return name;
1260 }
1261
1262 static struct ref **tail_ref(struct ref **head)
1263 {
1264         struct ref **tail = head;
1265         while (*tail)
1266                 tail = &((*tail)->next);
1267         return tail;
1268 }
1269
1270 struct tips {
1271         struct commit **tip;
1272         int nr, alloc;
1273 };
1274
1275 static void add_to_tips(struct tips *tips, const unsigned char *sha1)
1276 {
1277         struct commit *commit;
1278
1279         if (is_null_sha1(sha1))
1280                 return;
1281         commit = lookup_commit_reference_gently(sha1, 1);
1282         if (!commit || (commit->object.flags & TMP_MARK))
1283                 return;
1284         commit->object.flags |= TMP_MARK;
1285         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1286         tips->tip[tips->nr++] = commit;
1287 }
1288
1289 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1290 {
1291         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1292         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1293         struct string_list_item *item;
1294         struct ref *ref;
1295         struct tips sent_tips;
1296
1297         /*
1298          * Collect everything we know they would have at the end of
1299          * this push, and collect all tags they have.
1300          */
1301         memset(&sent_tips, 0, sizeof(sent_tips));
1302         for (ref = *dst; ref; ref = ref->next) {
1303                 if (ref->peer_ref &&
1304                     !is_null_sha1(ref->peer_ref->new_sha1))
1305                         add_to_tips(&sent_tips, ref->peer_ref->new_sha1);
1306                 else
1307                         add_to_tips(&sent_tips, ref->old_sha1);
1308                 if (starts_with(ref->name, "refs/tags/"))
1309                         string_list_append(&dst_tag, ref->name);
1310         }
1311         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1312
1313         sort_string_list(&dst_tag);
1314
1315         /* Collect tags they do not have. */
1316         for (ref = src; ref; ref = ref->next) {
1317                 if (!starts_with(ref->name, "refs/tags/"))
1318                         continue; /* not a tag */
1319                 if (string_list_has_string(&dst_tag, ref->name))
1320                         continue; /* they already have it */
1321                 if (sha1_object_info(ref->new_sha1, NULL) != OBJ_TAG)
1322                         continue; /* be conservative */
1323                 item = string_list_append(&src_tag, ref->name);
1324                 item->util = ref;
1325         }
1326         string_list_clear(&dst_tag, 0);
1327
1328         /*
1329          * At this point, src_tag lists tags that are missing from
1330          * dst, and sent_tips lists the tips we are pushing or those
1331          * that we know they already have. An element in the src_tag
1332          * that is an ancestor of any of the sent_tips needs to be
1333          * sent to the other side.
1334          */
1335         if (sent_tips.nr) {
1336                 for_each_string_list_item(item, &src_tag) {
1337                         struct ref *ref = item->util;
1338                         struct ref *dst_ref;
1339                         struct commit *commit;
1340
1341                         if (is_null_sha1(ref->new_sha1))
1342                                 continue;
1343                         commit = lookup_commit_reference_gently(ref->new_sha1, 1);
1344                         if (!commit)
1345                                 /* not pushing a commit, which is not an error */
1346                                 continue;
1347
1348                         /*
1349                          * Is this tag, which they do not have, reachable from
1350                          * any of the commits we are sending?
1351                          */
1352                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1353                                 continue;
1354
1355                         /* Add it in */
1356                         dst_ref = make_linked_ref(ref->name, dst_tail);
1357                         hashcpy(dst_ref->new_sha1, ref->new_sha1);
1358                         dst_ref->peer_ref = copy_ref(ref);
1359                 }
1360         }
1361         string_list_clear(&src_tag, 0);
1362         free(sent_tips.tip);
1363 }
1364
1365 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1366 {
1367         for ( ; list; list = list->next)
1368                 if (!strcmp(list->name, name))
1369                         return (struct ref *)list;
1370         return NULL;
1371 }
1372
1373 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1374 {
1375         for ( ; ref; ref = ref->next)
1376                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1377
1378         sort_string_list(ref_index);
1379 }
1380
1381 /*
1382  * Given only the set of local refs, sanity-check the set of push
1383  * refspecs. We can't catch all errors that match_push_refs would,
1384  * but we can catch some errors early before even talking to the
1385  * remote side.
1386  */
1387 int check_push_refs(struct ref *src, int nr_refspec, const char **refspec_names)
1388 {
1389         struct refspec *refspec = parse_push_refspec(nr_refspec, refspec_names);
1390         int ret = 0;
1391         int i;
1392
1393         for (i = 0; i < nr_refspec; i++) {
1394                 struct refspec *rs = refspec + i;
1395
1396                 if (rs->pattern || rs->matching)
1397                         continue;
1398
1399                 ret |= match_explicit_lhs(src, rs, NULL, NULL);
1400         }
1401
1402         free_refspec(nr_refspec, refspec);
1403         return ret;
1404 }
1405
1406 /*
1407  * Given the set of refs the local repository has, the set of refs the
1408  * remote repository has, and the refspec used for push, determine
1409  * what remote refs we will update and with what value by setting
1410  * peer_ref (which object is being pushed) and force (if the push is
1411  * forced) in elements of "dst". The function may add new elements to
1412  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1413  */
1414 int match_push_refs(struct ref *src, struct ref **dst,
1415                     int nr_refspec, const char **refspec, int flags)
1416 {
1417         struct refspec *rs;
1418         int send_all = flags & MATCH_REFS_ALL;
1419         int send_mirror = flags & MATCH_REFS_MIRROR;
1420         int send_prune = flags & MATCH_REFS_PRUNE;
1421         int errs;
1422         static const char *default_refspec[] = { ":", NULL };
1423         struct ref *ref, **dst_tail = tail_ref(dst);
1424         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1425
1426         if (!nr_refspec) {
1427                 nr_refspec = 1;
1428                 refspec = default_refspec;
1429         }
1430         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1431         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1432
1433         /* pick the remainder */
1434         for (ref = src; ref; ref = ref->next) {
1435                 struct string_list_item *dst_item;
1436                 struct ref *dst_peer;
1437                 const struct refspec *pat = NULL;
1438                 char *dst_name;
1439
1440                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1441                 if (!dst_name)
1442                         continue;
1443
1444                 if (!dst_ref_index.nr)
1445                         prepare_ref_index(&dst_ref_index, *dst);
1446
1447                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1448                 dst_peer = dst_item ? dst_item->util : NULL;
1449                 if (dst_peer) {
1450                         if (dst_peer->peer_ref)
1451                                 /* We're already sending something to this ref. */
1452                                 goto free_name;
1453                 } else {
1454                         if (pat->matching && !(send_all || send_mirror))
1455                                 /*
1456                                  * Remote doesn't have it, and we have no
1457                                  * explicit pattern, and we don't have
1458                                  * --all nor --mirror.
1459                                  */
1460                                 goto free_name;
1461
1462                         /* Create a new one and link it */
1463                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1464                         hashcpy(dst_peer->new_sha1, ref->new_sha1);
1465                         string_list_insert(&dst_ref_index,
1466                                 dst_peer->name)->util = dst_peer;
1467                 }
1468                 dst_peer->peer_ref = copy_ref(ref);
1469                 dst_peer->force = pat->force;
1470         free_name:
1471                 free(dst_name);
1472         }
1473
1474         string_list_clear(&dst_ref_index, 0);
1475
1476         if (flags & MATCH_REFS_FOLLOW_TAGS)
1477                 add_missing_tags(src, dst, &dst_tail);
1478
1479         if (send_prune) {
1480                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1481                 /* check for missing refs on the remote */
1482                 for (ref = *dst; ref; ref = ref->next) {
1483                         char *src_name;
1484
1485                         if (ref->peer_ref)
1486                                 /* We're already sending something to this ref. */
1487                                 continue;
1488
1489                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1490                         if (src_name) {
1491                                 if (!src_ref_index.nr)
1492                                         prepare_ref_index(&src_ref_index, src);
1493                                 if (!string_list_has_string(&src_ref_index,
1494                                             src_name))
1495                                         ref->peer_ref = alloc_delete_ref();
1496                                 free(src_name);
1497                         }
1498                 }
1499                 string_list_clear(&src_ref_index, 0);
1500         }
1501         if (errs)
1502                 return -1;
1503         return 0;
1504 }
1505
1506 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1507                              int force_update)
1508 {
1509         struct ref *ref;
1510
1511         for (ref = remote_refs; ref; ref = ref->next) {
1512                 int force_ref_update = ref->force || force_update;
1513                 int reject_reason = 0;
1514
1515                 if (ref->peer_ref)
1516                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1517                 else if (!send_mirror)
1518                         continue;
1519
1520                 ref->deletion = is_null_sha1(ref->new_sha1);
1521                 if (!ref->deletion &&
1522                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1523                         ref->status = REF_STATUS_UPTODATE;
1524                         continue;
1525                 }
1526
1527                 /*
1528                  * Bypass the usual "must fast-forward" check but
1529                  * replace it with a weaker "the old value must be
1530                  * this value we observed".  If the remote ref has
1531                  * moved and is now different from what we expect,
1532                  * reject any push.
1533                  *
1534                  * It also is an error if the user told us to check
1535                  * with the remote-tracking branch to find the value
1536                  * to expect, but we did not have such a tracking
1537                  * branch.
1538                  */
1539                 if (ref->expect_old_sha1) {
1540                         if (ref->expect_old_no_trackback ||
1541                             hashcmp(ref->old_sha1, ref->old_sha1_expect))
1542                                 reject_reason = REF_STATUS_REJECT_STALE;
1543                 }
1544
1545                 /*
1546                  * The usual "must fast-forward" rules.
1547                  *
1548                  * Decide whether an individual refspec A:B can be
1549                  * pushed.  The push will succeed if any of the
1550                  * following are true:
1551                  *
1552                  * (1) the remote reference B does not exist
1553                  *
1554                  * (2) the remote reference B is being removed (i.e.,
1555                  *     pushing :B where no source is specified)
1556                  *
1557                  * (3) the destination is not under refs/tags/, and
1558                  *     if the old and new value is a commit, the new
1559                  *     is a descendant of the old.
1560                  *
1561                  * (4) it is forced using the +A:B notation, or by
1562                  *     passing the --force argument
1563                  */
1564
1565                 else if (!ref->deletion && !is_null_sha1(ref->old_sha1)) {
1566                         if (starts_with(ref->name, "refs/tags/"))
1567                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1568                         else if (!has_sha1_file(ref->old_sha1))
1569                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1570                         else if (!lookup_commit_reference_gently(ref->old_sha1, 1) ||
1571                                  !lookup_commit_reference_gently(ref->new_sha1, 1))
1572                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1573                         else if (!ref_newer(ref->new_sha1, ref->old_sha1))
1574                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1575                 }
1576
1577                 /*
1578                  * "--force" will defeat any rejection implemented
1579                  * by the rules above.
1580                  */
1581                 if (!force_ref_update)
1582                         ref->status = reject_reason;
1583                 else if (reject_reason)
1584                         ref->forced_update = 1;
1585         }
1586 }
1587
1588 struct branch *branch_get(const char *name)
1589 {
1590         struct branch *ret;
1591
1592         read_config();
1593         if (!name || !*name || !strcmp(name, "HEAD"))
1594                 ret = current_branch;
1595         else
1596                 ret = make_branch(name, 0);
1597         if (ret && ret->remote_name) {
1598                 ret->remote = remote_get(ret->remote_name);
1599                 if (ret->merge_nr) {
1600                         int i;
1601                         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1602                         for (i = 0; i < ret->merge_nr; i++) {
1603                                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1604                                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1605                                 if (remote_find_tracking(ret->remote, ret->merge[i])
1606                                     && !strcmp(ret->remote_name, "."))
1607                                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1608                         }
1609                 }
1610         }
1611         return ret;
1612 }
1613
1614 int branch_has_merge_config(struct branch *branch)
1615 {
1616         return branch && !!branch->merge;
1617 }
1618
1619 int branch_merge_matches(struct branch *branch,
1620                                  int i,
1621                                  const char *refname)
1622 {
1623         if (!branch || i < 0 || i >= branch->merge_nr)
1624                 return 0;
1625         return refname_match(branch->merge[i]->src, refname);
1626 }
1627
1628 static int ignore_symref_update(const char *refname)
1629 {
1630         unsigned char sha1[20];
1631         int flag;
1632
1633         if (!resolve_ref_unsafe(refname, sha1, 0, &flag))
1634                 return 0; /* non-existing refs are OK */
1635         return (flag & REF_ISSYMREF);
1636 }
1637
1638 /*
1639  * Create and return a list of (struct ref) consisting of copies of
1640  * each remote_ref that matches refspec.  refspec must be a pattern.
1641  * Fill in the copies' peer_ref to describe the local tracking refs to
1642  * which they map.  Omit any references that would map to an existing
1643  * local symbolic ref.
1644  */
1645 static struct ref *get_expanded_map(const struct ref *remote_refs,
1646                                     const struct refspec *refspec)
1647 {
1648         const struct ref *ref;
1649         struct ref *ret = NULL;
1650         struct ref **tail = &ret;
1651
1652         for (ref = remote_refs; ref; ref = ref->next) {
1653                 char *expn_name = NULL;
1654
1655                 if (strchr(ref->name, '^'))
1656                         continue; /* a dereference item */
1657                 if (match_name_with_pattern(refspec->src, ref->name,
1658                                             refspec->dst, &expn_name) &&
1659                     !ignore_symref_update(expn_name)) {
1660                         struct ref *cpy = copy_ref(ref);
1661
1662                         cpy->peer_ref = alloc_ref(expn_name);
1663                         if (refspec->force)
1664                                 cpy->peer_ref->force = 1;
1665                         *tail = cpy;
1666                         tail = &cpy->next;
1667                 }
1668                 free(expn_name);
1669         }
1670
1671         return ret;
1672 }
1673
1674 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1675 {
1676         const struct ref *ref;
1677         for (ref = refs; ref; ref = ref->next) {
1678                 if (refname_match(name, ref->name))
1679                         return ref;
1680         }
1681         return NULL;
1682 }
1683
1684 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1685 {
1686         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1687
1688         if (!ref)
1689                 return NULL;
1690
1691         return copy_ref(ref);
1692 }
1693
1694 static struct ref *get_local_ref(const char *name)
1695 {
1696         if (!name || name[0] == '\0')
1697                 return NULL;
1698
1699         if (starts_with(name, "refs/"))
1700                 return alloc_ref(name);
1701
1702         if (starts_with(name, "heads/") ||
1703             starts_with(name, "tags/") ||
1704             starts_with(name, "remotes/"))
1705                 return alloc_ref_with_prefix("refs/", 5, name);
1706
1707         return alloc_ref_with_prefix("refs/heads/", 11, name);
1708 }
1709
1710 int get_fetch_map(const struct ref *remote_refs,
1711                   const struct refspec *refspec,
1712                   struct ref ***tail,
1713                   int missing_ok)
1714 {
1715         struct ref *ref_map, **rmp;
1716
1717         if (refspec->pattern) {
1718                 ref_map = get_expanded_map(remote_refs, refspec);
1719         } else {
1720                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1721
1722                 if (refspec->exact_sha1) {
1723                         ref_map = alloc_ref(name);
1724                         get_sha1_hex(name, ref_map->old_sha1);
1725                 } else {
1726                         ref_map = get_remote_ref(remote_refs, name);
1727                 }
1728                 if (!missing_ok && !ref_map)
1729                         die("Couldn't find remote ref %s", name);
1730                 if (ref_map) {
1731                         ref_map->peer_ref = get_local_ref(refspec->dst);
1732                         if (ref_map->peer_ref && refspec->force)
1733                                 ref_map->peer_ref->force = 1;
1734                 }
1735         }
1736
1737         for (rmp = &ref_map; *rmp; ) {
1738                 if ((*rmp)->peer_ref) {
1739                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1740                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1741                                 struct ref *ignore = *rmp;
1742                                 error("* Ignoring funny ref '%s' locally",
1743                                       (*rmp)->peer_ref->name);
1744                                 *rmp = (*rmp)->next;
1745                                 free(ignore->peer_ref);
1746                                 free(ignore);
1747                                 continue;
1748                         }
1749                 }
1750                 rmp = &((*rmp)->next);
1751         }
1752
1753         if (ref_map)
1754                 tail_link_ref(ref_map, tail);
1755
1756         return 0;
1757 }
1758
1759 int resolve_remote_symref(struct ref *ref, struct ref *list)
1760 {
1761         if (!ref->symref)
1762                 return 0;
1763         for (; list; list = list->next)
1764                 if (!strcmp(ref->symref, list->name)) {
1765                         hashcpy(ref->old_sha1, list->old_sha1);
1766                         return 0;
1767                 }
1768         return 1;
1769 }
1770
1771 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1772 {
1773         while (list) {
1774                 struct commit_list *temp = list;
1775                 temp->item->object.flags &= ~mark;
1776                 list = temp->next;
1777                 free(temp);
1778         }
1779 }
1780
1781 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1782 {
1783         struct object *o;
1784         struct commit *old, *new;
1785         struct commit_list *list, *used;
1786         int found = 0;
1787
1788         /*
1789          * Both new and old must be commit-ish and new is descendant of
1790          * old.  Otherwise we require --force.
1791          */
1792         o = deref_tag(parse_object(old_sha1), NULL, 0);
1793         if (!o || o->type != OBJ_COMMIT)
1794                 return 0;
1795         old = (struct commit *) o;
1796
1797         o = deref_tag(parse_object(new_sha1), NULL, 0);
1798         if (!o || o->type != OBJ_COMMIT)
1799                 return 0;
1800         new = (struct commit *) o;
1801
1802         if (parse_commit(new) < 0)
1803                 return 0;
1804
1805         used = list = NULL;
1806         commit_list_insert(new, &list);
1807         while (list) {
1808                 new = pop_most_recent_commit(&list, TMP_MARK);
1809                 commit_list_insert(new, &used);
1810                 if (new == old) {
1811                         found = 1;
1812                         break;
1813                 }
1814         }
1815         unmark_and_free(list, TMP_MARK);
1816         unmark_and_free(used, TMP_MARK);
1817         return found;
1818 }
1819
1820 /*
1821  * Compare a branch with its upstream, and save their differences (number
1822  * of commits) in *num_ours and *num_theirs.
1823  *
1824  * Return 0 if branch has no upstream (no base), -1 if upstream is missing
1825  * (with "gone" base), otherwise 1 (with base).
1826  */
1827 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
1828 {
1829         unsigned char sha1[20];
1830         struct commit *ours, *theirs;
1831         char symmetric[84];
1832         struct rev_info revs;
1833         const char *rev_argv[10], *base;
1834         int rev_argc;
1835
1836         /* Cannot stat unless we are marked to build on top of somebody else. */
1837         if (!branch ||
1838             !branch->merge || !branch->merge[0] || !branch->merge[0]->dst)
1839                 return 0;
1840
1841         /* Cannot stat if what we used to build on no longer exists */
1842         base = branch->merge[0]->dst;
1843         if (read_ref(base, sha1))
1844                 return -1;
1845         theirs = lookup_commit_reference(sha1);
1846         if (!theirs)
1847                 return -1;
1848
1849         if (read_ref(branch->refname, sha1))
1850                 return -1;
1851         ours = lookup_commit_reference(sha1);
1852         if (!ours)
1853                 return -1;
1854
1855         /* are we the same? */
1856         if (theirs == ours) {
1857                 *num_theirs = *num_ours = 0;
1858                 return 1;
1859         }
1860
1861         /* Run "rev-list --left-right ours...theirs" internally... */
1862         rev_argc = 0;
1863         rev_argv[rev_argc++] = NULL;
1864         rev_argv[rev_argc++] = "--left-right";
1865         rev_argv[rev_argc++] = symmetric;
1866         rev_argv[rev_argc++] = "--";
1867         rev_argv[rev_argc] = NULL;
1868
1869         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
1870         strcpy(symmetric + 40, "...");
1871         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
1872
1873         init_revisions(&revs, NULL);
1874         setup_revisions(rev_argc, rev_argv, &revs, NULL);
1875         prepare_revision_walk(&revs);
1876
1877         /* ... and count the commits on each side. */
1878         *num_ours = 0;
1879         *num_theirs = 0;
1880         while (1) {
1881                 struct commit *c = get_revision(&revs);
1882                 if (!c)
1883                         break;
1884                 if (c->object.flags & SYMMETRIC_LEFT)
1885                         (*num_ours)++;
1886                 else
1887                         (*num_theirs)++;
1888         }
1889
1890         /* clear object flags smudged by the above traversal */
1891         clear_commit_marks(ours, ALL_REV_FLAGS);
1892         clear_commit_marks(theirs, ALL_REV_FLAGS);
1893         return 1;
1894 }
1895
1896 /*
1897  * Return true when there is anything to report, otherwise false.
1898  */
1899 int format_tracking_info(struct branch *branch, struct strbuf *sb)
1900 {
1901         int ours, theirs;
1902         const char *base;
1903         int upstream_is_gone = 0;
1904
1905         switch (stat_tracking_info(branch, &ours, &theirs)) {
1906         case 0:
1907                 /* no base */
1908                 return 0;
1909         case -1:
1910                 /* with "gone" base */
1911                 upstream_is_gone = 1;
1912                 break;
1913         default:
1914                 /* with base */
1915                 break;
1916         }
1917
1918         base = branch->merge[0]->dst;
1919         base = shorten_unambiguous_ref(base, 0);
1920         if (upstream_is_gone) {
1921                 strbuf_addf(sb,
1922                         _("Your branch is based on '%s', but the upstream is gone.\n"),
1923                         base);
1924                 if (advice_status_hints)
1925                         strbuf_addf(sb,
1926                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
1927         } else if (!ours && !theirs) {
1928                 strbuf_addf(sb,
1929                         _("Your branch is up-to-date with '%s'.\n"),
1930                         base);
1931         } else if (!theirs) {
1932                 strbuf_addf(sb,
1933                         Q_("Your branch is ahead of '%s' by %d commit.\n",
1934                            "Your branch is ahead of '%s' by %d commits.\n",
1935                            ours),
1936                         base, ours);
1937                 if (advice_status_hints)
1938                         strbuf_addf(sb,
1939                                 _("  (use \"git push\" to publish your local commits)\n"));
1940         } else if (!ours) {
1941                 strbuf_addf(sb,
1942                         Q_("Your branch is behind '%s' by %d commit, "
1943                                "and can be fast-forwarded.\n",
1944                            "Your branch is behind '%s' by %d commits, "
1945                                "and can be fast-forwarded.\n",
1946                            theirs),
1947                         base, theirs);
1948                 if (advice_status_hints)
1949                         strbuf_addf(sb,
1950                                 _("  (use \"git pull\" to update your local branch)\n"));
1951         } else {
1952                 strbuf_addf(sb,
1953                         Q_("Your branch and '%s' have diverged,\n"
1954                                "and have %d and %d different commit each, "
1955                                "respectively.\n",
1956                            "Your branch and '%s' have diverged,\n"
1957                                "and have %d and %d different commits each, "
1958                                "respectively.\n",
1959                            theirs),
1960                         base, ours, theirs);
1961                 if (advice_status_hints)
1962                         strbuf_addf(sb,
1963                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
1964         }
1965         return 1;
1966 }
1967
1968 static int one_local_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
1969 {
1970         struct ref ***local_tail = cb_data;
1971         struct ref *ref;
1972         int len;
1973
1974         /* we already know it starts with refs/ to get here */
1975         if (check_refname_format(refname + 5, 0))
1976                 return 0;
1977
1978         len = strlen(refname) + 1;
1979         ref = xcalloc(1, sizeof(*ref) + len);
1980         hashcpy(ref->new_sha1, sha1);
1981         memcpy(ref->name, refname, len);
1982         **local_tail = ref;
1983         *local_tail = &ref->next;
1984         return 0;
1985 }
1986
1987 struct ref *get_local_heads(void)
1988 {
1989         struct ref *local_refs = NULL, **local_tail = &local_refs;
1990         for_each_ref(one_local_ref, &local_tail);
1991         return local_refs;
1992 }
1993
1994 struct ref *guess_remote_head(const struct ref *head,
1995                               const struct ref *refs,
1996                               int all)
1997 {
1998         const struct ref *r;
1999         struct ref *list = NULL;
2000         struct ref **tail = &list;
2001
2002         if (!head)
2003                 return NULL;
2004
2005         /*
2006          * Some transports support directly peeking at
2007          * where HEAD points; if that is the case, then
2008          * we don't have to guess.
2009          */
2010         if (head->symref)
2011                 return copy_ref(find_ref_by_name(refs, head->symref));
2012
2013         /* If refs/heads/master could be right, it is. */
2014         if (!all) {
2015                 r = find_ref_by_name(refs, "refs/heads/master");
2016                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
2017                         return copy_ref(r);
2018         }
2019
2020         /* Look for another ref that points there */
2021         for (r = refs; r; r = r->next) {
2022                 if (r != head &&
2023                     starts_with(r->name, "refs/heads/") &&
2024                     !hashcmp(r->old_sha1, head->old_sha1)) {
2025                         *tail = copy_ref(r);
2026                         tail = &((*tail)->next);
2027                         if (!all)
2028                                 break;
2029                 }
2030         }
2031
2032         return list;
2033 }
2034
2035 struct stale_heads_info {
2036         struct string_list *ref_names;
2037         struct ref **stale_refs_tail;
2038         struct refspec *refs;
2039         int ref_count;
2040 };
2041
2042 static int get_stale_heads_cb(const char *refname,
2043         const unsigned char *sha1, int flags, void *cb_data)
2044 {
2045         struct stale_heads_info *info = cb_data;
2046         struct refspec query;
2047         memset(&query, 0, sizeof(struct refspec));
2048         query.dst = (char *)refname;
2049
2050         if (query_refspecs(info->refs, info->ref_count, &query))
2051                 return 0; /* No matches */
2052
2053         /*
2054          * If we did find a suitable refspec and it's not a symref and
2055          * it's not in the list of refs that currently exist in that
2056          * remote we consider it to be stale.
2057          */
2058         if (!((flags & REF_ISSYMREF) ||
2059               string_list_has_string(info->ref_names, query.src))) {
2060                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2061                 hashcpy(ref->new_sha1, sha1);
2062         }
2063
2064         free(query.src);
2065         return 0;
2066 }
2067
2068 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
2069 {
2070         struct ref *ref, *stale_refs = NULL;
2071         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2072         struct stale_heads_info info;
2073         info.ref_names = &ref_names;
2074         info.stale_refs_tail = &stale_refs;
2075         info.refs = refs;
2076         info.ref_count = ref_count;
2077         for (ref = fetch_map; ref; ref = ref->next)
2078                 string_list_append(&ref_names, ref->name);
2079         sort_string_list(&ref_names);
2080         for_each_ref(get_stale_heads_cb, &info);
2081         string_list_clear(&ref_names, 0);
2082         return stale_refs;
2083 }
2084
2085 /*
2086  * Compare-and-swap
2087  */
2088 void clear_cas_option(struct push_cas_option *cas)
2089 {
2090         int i;
2091
2092         for (i = 0; i < cas->nr; i++)
2093                 free(cas->entry[i].refname);
2094         free(cas->entry);
2095         memset(cas, 0, sizeof(*cas));
2096 }
2097
2098 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2099                                       const char *refname,
2100                                       size_t refnamelen)
2101 {
2102         struct push_cas *entry;
2103         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2104         entry = &cas->entry[cas->nr++];
2105         memset(entry, 0, sizeof(*entry));
2106         entry->refname = xmemdupz(refname, refnamelen);
2107         return entry;
2108 }
2109
2110 int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2111 {
2112         const char *colon;
2113         struct push_cas *entry;
2114
2115         if (unset) {
2116                 /* "--no-<option>" */
2117                 clear_cas_option(cas);
2118                 return 0;
2119         }
2120
2121         if (!arg) {
2122                 /* just "--<option>" */
2123                 cas->use_tracking_for_rest = 1;
2124                 return 0;
2125         }
2126
2127         /* "--<option>=refname" or "--<option>=refname:value" */
2128         colon = strchrnul(arg, ':');
2129         entry = add_cas_entry(cas, arg, colon - arg);
2130         if (!*colon)
2131                 entry->use_tracking = 1;
2132         else if (get_sha1(colon + 1, entry->expect))
2133                 return error("cannot parse expected object name '%s'", colon + 1);
2134         return 0;
2135 }
2136
2137 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2138 {
2139         return parse_push_cas_option(opt->value, arg, unset);
2140 }
2141
2142 int is_empty_cas(const struct push_cas_option *cas)
2143 {
2144         return !cas->use_tracking_for_rest && !cas->nr;
2145 }
2146
2147 /*
2148  * Look at remote.fetch refspec and see if we have a remote
2149  * tracking branch for the refname there.  Fill its current
2150  * value in sha1[].
2151  * If we cannot do so, return negative to signal an error.
2152  */
2153 static int remote_tracking(struct remote *remote, const char *refname,
2154                            unsigned char sha1[20])
2155 {
2156         char *dst;
2157
2158         dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
2159         if (!dst)
2160                 return -1; /* no tracking ref for refname at remote */
2161         if (read_ref(dst, sha1))
2162                 return -1; /* we know what the tracking ref is but we cannot read it */
2163         return 0;
2164 }
2165
2166 static void apply_cas(struct push_cas_option *cas,
2167                       struct remote *remote,
2168                       struct ref *ref)
2169 {
2170         int i;
2171
2172         /* Find an explicit --<option>=<name>[:<value>] entry */
2173         for (i = 0; i < cas->nr; i++) {
2174                 struct push_cas *entry = &cas->entry[i];
2175                 if (!refname_match(entry->refname, ref->name))
2176                         continue;
2177                 ref->expect_old_sha1 = 1;
2178                 if (!entry->use_tracking)
2179                         hashcpy(ref->old_sha1_expect, cas->entry[i].expect);
2180                 else if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2181                         ref->expect_old_no_trackback = 1;
2182                 return;
2183         }
2184
2185         /* Are we using "--<option>" to cover all? */
2186         if (!cas->use_tracking_for_rest)
2187                 return;
2188
2189         ref->expect_old_sha1 = 1;
2190         if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2191                 ref->expect_old_no_trackback = 1;
2192 }
2193
2194 void apply_push_cas(struct push_cas_option *cas,
2195                     struct remote *remote,
2196                     struct ref *remote_refs)
2197 {
2198         struct ref *ref;
2199         for (ref = remote_refs; ref; ref = ref->next)
2200                 apply_cas(cas, remote, ref);
2201 }