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 static struct hashmap remotes_hash;
  46
  47 static struct branch **branches;
  48 static int branches_alloc;
  49 static int branches_nr;
  50
  51 static struct branch *current_branch;
  52 static const char *pushremote_name;
  53
  54 static struct rewrites rewrites;
  55 static struct rewrites rewrites_push;
  56
  57 static int valid_remote(const struct remote *remote)
  58 {
  59         return (!!remote->url) || (!!remote->foreign_vcs);
  60 }
  61
  62 static const char *alias_url(const char *url, struct rewrites *r)
  63 {
  64         int i, j;
  65         struct counted_string *longest;
  66         int longest_i;
  67
  68         longest = NULL;
  69         longest_i = -1;
  70         for (i = 0; i < r->rewrite_nr; i++) {
  71                 if (!r->rewrite[i])
  72                         continue;
  73                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  74                         if (starts_with(url, r->rewrite[i]->instead_of[j].s) &&
  75                             (!longest ||
  76                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  77                                 longest = &(r->rewrite[i]->instead_of[j]);
  78                                 longest_i = i;
  79                         }
  80                 }
  81         }
  82         if (!longest)
  83                 return url;
  84
  85         return xstrfmt("%s%s", r->rewrite[longest_i]->base, url + longest->len);
  86 }
  87
  88 static void add_push_refspec(struct remote *remote, const char *ref)
  89 {
  90         ALLOC_GROW(remote->push_refspec,
  91                    remote->push_refspec_nr + 1,
  92                    remote->push_refspec_alloc);
  93         remote->push_refspec[remote->push_refspec_nr++] = ref;
  94 }
  95
  96 static void add_fetch_refspec(struct remote *remote, const char *ref)
  97 {
  98         ALLOC_GROW(remote->fetch_refspec,
  99                    remote->fetch_refspec_nr + 1,
 100                    remote->fetch_refspec_alloc);
 101         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
 102 }
 103
 104 static void add_url(struct remote *remote, const char *url)
 105 {
 106         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
 107         remote->url[remote->url_nr++] = url;
 108 }
 109
 110 static void add_pushurl(struct remote *remote, const char *pushurl)
 111 {
 112         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
 113         remote->pushurl[remote->pushurl_nr++] = pushurl;
 114 }
 115
 116 static void add_pushurl_alias(struct remote *remote, const char *url)
 117 {
 118         const char *pushurl = alias_url(url, &rewrites_push);
 119         if (pushurl != url)
 120                 add_pushurl(remote, pushurl);
 121 }
 122
 123 static void add_url_alias(struct remote *remote, const char *url)
 124 {
 125         add_url(remote, alias_url(url, &rewrites));
 126         add_pushurl_alias(remote, url);
 127 }
 128
 129 struct remotes_hash_key {
 130         const char *str;
 131         int len;
 132 };
 133
 134 static int remotes_hash_cmp(const struct remote *a, const struct remote *b, const struct remotes_hash_key *key)
 135 {
 136         if (key)
 137                 return strncmp(a->name, key->str, key->len) || a->name[key->len];
 138         else
 139                 return strcmp(a->name, b->name);
 140 }
 141
 142 static inline void init_remotes_hash(void)
 143 {
 144         if (!remotes_hash.cmpfn)
 145                 hashmap_init(&remotes_hash, (hashmap_cmp_fn)remotes_hash_cmp, 0);
 146 }
 147
 148 static struct remote *make_remote(const char *name, int len)
 149 {
 150         struct remote *ret, *replaced;
 151         struct remotes_hash_key lookup;
 152         struct hashmap_entry lookup_entry;
 153
 154         if (!len)
 155                 len = strlen(name);
 156
 157         init_remotes_hash();
 158         lookup.str = name;
 159         lookup.len = len;
 160         hashmap_entry_init(&lookup_entry, memhash(name, len));
 161
 162         if ((ret = hashmap_get(&remotes_hash, &lookup_entry, &lookup)) != NULL)
 163                 return ret;
 164
 165         ret = xcalloc(1, sizeof(struct remote));
 166         ret->prune = -1;  /* unspecified */
 167         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 168         remotes[remotes_nr++] = ret;
 169         ret->name = xstrndup(name, len);
 170
 171         hashmap_entry_init(ret, lookup_entry.hash);
 172         replaced = hashmap_put(&remotes_hash, ret);
 173         assert(replaced == NULL);  /* no previous entry overwritten */
 174         return ret;
 175 }
 176
 177 static void add_merge(struct branch *branch, const char *name)
 178 {
 179         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 180                    branch->merge_alloc);
 181         branch->merge_name[branch->merge_nr++] = name;
 182 }
 183
 184 static struct branch *make_branch(const char *name, int len)
 185 {
 186         struct branch *ret;
 187         int i;
 188
 189         for (i = 0; i < branches_nr; i++) {
 190                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 191                            !branches[i]->name[len]) :
 192                     !strcmp(name, branches[i]->name))
 193                         return branches[i];
 194         }
 195
 196         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 197         ret = xcalloc(1, sizeof(struct branch));
 198         branches[branches_nr++] = ret;
 199         if (len)
 200                 ret->name = xstrndup(name, len);
 201         else
 202                 ret->name = xstrdup(name);
 203         ret->refname = xstrfmt("refs/heads/%s", ret->name);
 204
 205         return ret;
 206 }
 207
 208 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 209 {
 210         struct rewrite *ret;
 211         int i;
 212
 213         for (i = 0; i < r->rewrite_nr; i++) {
 214                 if (len
 215                     ? (len == r->rewrite[i]->baselen &&
 216                        !strncmp(base, r->rewrite[i]->base, len))
 217                     : !strcmp(base, r->rewrite[i]->base))
 218                         return r->rewrite[i];
 219         }
 220
 221         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 222         ret = xcalloc(1, sizeof(struct rewrite));
 223         r->rewrite[r->rewrite_nr++] = ret;
 224         if (len) {
 225                 ret->base = xstrndup(base, len);
 226                 ret->baselen = len;
 227         }
 228         else {
 229                 ret->base = xstrdup(base);
 230                 ret->baselen = strlen(base);
 231         }
 232         return ret;
 233 }
 234
 235 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 236 {
 237         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 238         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 239         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 240         rewrite->instead_of_nr++;
 241 }
 242
 243 static const char *skip_spaces(const char *s)
 244 {
 245         while (isspace(*s))
 246                 s++;
 247         return s;
 248 }
 249
 250 static void read_remotes_file(struct remote *remote)
 251 {
 252         struct strbuf buf = STRBUF_INIT;
 253         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 254
 255         if (!f)
 256                 return;
 257         remote->origin = REMOTE_REMOTES;
 258         while (strbuf_getline(&buf, f, '\n') != EOF) {
 259                 const char *v;
 260
 261                 strbuf_rtrim(&buf);
 262
 263                 if (skip_prefix(buf.buf, "URL:", &v))
 264                         add_url_alias(remote, xstrdup(skip_spaces(v)));
 265                 else if (skip_prefix(buf.buf, "Push:", &v))
 266                         add_push_refspec(remote, xstrdup(skip_spaces(v)));
 267                 else if (skip_prefix(buf.buf, "Pull:", &v))
 268                         add_fetch_refspec(remote, xstrdup(skip_spaces(v)));
 269         }
 270         strbuf_release(&buf);
 271         fclose(f);
 272 }
 273
 274 static void read_branches_file(struct remote *remote)
 275 {
 276         char *frag;
 277         struct strbuf buf = STRBUF_INIT;
 278         FILE *f = fopen(git_path("branches/%s", remote->name), "r");
 279
 280         if (!f)
 281                 return;
 282
 283         strbuf_getline(&buf, f, '\n');
 284         strbuf_trim(&buf);
 285         if (!buf.len) {
 286                 strbuf_release(&buf);
 287                 return;
 288         }
 289
 290         remote->origin = REMOTE_BRANCHES;
 291
 292         /*
 293          * The branches file would have URL and optionally
 294          * #branch specified.  The "master" (or specified) branch is
 295          * fetched and stored in the local branch matching the
 296          * remote name.
 297          */
 298         frag = strchr(buf.buf, '#');
 299         if (frag)
 300                 *(frag++) = '\0';
 301         else
 302                 frag = "master";
 303
 304         add_url_alias(remote, strbuf_detach(&buf, NULL));
 305         add_fetch_refspec(remote, xstrfmt("refs/heads/%s:refs/heads/%s",
 306                                           frag, remote->name));
 307
 308         /*
 309          * Cogito compatible push: push current HEAD to remote #branch
 310          * (master if missing)
 311          */
 312         add_push_refspec(remote, xstrfmt("HEAD:refs/heads/%s", frag));
 313         remote->fetch_tags = 1; /* always auto-follow */
 314 }
 315
 316 static int handle_config(const char *key, const char *value, void *cb)
 317 {
 318         const char *name;
 319         const char *subkey;
 320         struct remote *remote;
 321         struct branch *branch;
 322         if (starts_with(key, "branch.")) {
 323                 name = key + 7;
 324                 subkey = strrchr(name, '.');
 325                 if (!subkey)
 326                         return 0;
 327                 branch = make_branch(name, subkey - name);
 328                 if (!strcmp(subkey, ".remote")) {
 329                         return git_config_string(&branch->remote_name, key, value);
 330                 } else if (!strcmp(subkey, ".pushremote")) {
 331                         return git_config_string(&branch->pushremote_name, key, value);
 332                 } else if (!strcmp(subkey, ".merge")) {
 333                         if (!value)
 334                                 return config_error_nonbool(key);
 335                         add_merge(branch, xstrdup(value));
 336                 }
 337                 return 0;
 338         }
 339         if (starts_with(key, "url.")) {
 340                 struct rewrite *rewrite;
 341                 name = key + 4;
 342                 subkey = strrchr(name, '.');
 343                 if (!subkey)
 344                         return 0;
 345                 if (!strcmp(subkey, ".insteadof")) {
 346                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 347                         if (!value)
 348                                 return config_error_nonbool(key);
 349                         add_instead_of(rewrite, xstrdup(value));
 350                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 351                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 352                         if (!value)
 353                                 return config_error_nonbool(key);
 354                         add_instead_of(rewrite, xstrdup(value));
 355                 }
 356         }
 357
 358         if (!starts_with(key,  "remote."))
 359                 return 0;
 360         name = key + 7;
 361
 362         /* Handle remote.* variables */
 363         if (!strcmp(name, "pushdefault"))
 364                 return git_config_string(&pushremote_name, key, value);
 365
 366         /* Handle remote.<name>.* variables */
 367         if (*name == '/') {
 368                 warning("Config remote shorthand cannot begin with '/': %s",
 369                         name);
 370                 return 0;
 371         }
 372         subkey = strrchr(name, '.');
 373         if (!subkey)
 374                 return 0;
 375         remote = make_remote(name, subkey - name);
 376         remote->origin = REMOTE_CONFIG;
 377         if (!strcmp(subkey, ".mirror"))
 378                 remote->mirror = git_config_bool(key, value);
 379         else if (!strcmp(subkey, ".skipdefaultupdate"))
 380                 remote->skip_default_update = git_config_bool(key, value);
 381         else if (!strcmp(subkey, ".skipfetchall"))
 382                 remote->skip_default_update = git_config_bool(key, value);
 383         else if (!strcmp(subkey, ".prune"))
 384                 remote->prune = git_config_bool(key, value);
 385         else if (!strcmp(subkey, ".url")) {
 386                 const char *v;
 387                 if (git_config_string(&v, key, value))
 388                         return -1;
 389                 add_url(remote, v);
 390         } else if (!strcmp(subkey, ".pushurl")) {
 391                 const char *v;
 392                 if (git_config_string(&v, key, value))
 393                         return -1;
 394                 add_pushurl(remote, v);
 395         } else if (!strcmp(subkey, ".push")) {
 396                 const char *v;
 397                 if (git_config_string(&v, key, value))
 398                         return -1;
 399                 add_push_refspec(remote, v);
 400         } else if (!strcmp(subkey, ".fetch")) {
 401                 const char *v;
 402                 if (git_config_string(&v, key, value))
 403                         return -1;
 404                 add_fetch_refspec(remote, v);
 405         } else if (!strcmp(subkey, ".receivepack")) {
 406                 const char *v;
 407                 if (git_config_string(&v, key, value))
 408                         return -1;
 409                 if (!remote->receivepack)
 410                         remote->receivepack = v;
 411                 else
 412                         error("more than one receivepack given, using the first");
 413         } else if (!strcmp(subkey, ".uploadpack")) {
 414                 const char *v;
 415                 if (git_config_string(&v, key, value))
 416                         return -1;
 417                 if (!remote->uploadpack)
 418                         remote->uploadpack = v;
 419                 else
 420                         error("more than one uploadpack given, using the first");
 421         } else if (!strcmp(subkey, ".tagopt")) {
 422                 if (!strcmp(value, "--no-tags"))
 423                         remote->fetch_tags = -1;
 424                 else if (!strcmp(value, "--tags"))
 425                         remote->fetch_tags = 2;
 426         } else if (!strcmp(subkey, ".proxy")) {
 427                 return git_config_string((const char **)&remote->http_proxy,
 428                                          key, value);
 429         } else if (!strcmp(subkey, ".vcs")) {
 430                 return git_config_string(&remote->foreign_vcs, key, value);
 431         }
 432         return 0;
 433 }
 434
 435 static void alias_all_urls(void)
 436 {
 437         int i, j;
 438         for (i = 0; i < remotes_nr; i++) {
 439                 int add_pushurl_aliases;
 440                 if (!remotes[i])
 441                         continue;
 442                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 443                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 444                 }
 445                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 446                 for (j = 0; j < remotes[i]->url_nr; j++) {
 447                         if (add_pushurl_aliases)
 448                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 449                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 450                 }
 451         }
 452 }
 453
 454 static void read_config(void)
 455 {
 456         static int loaded;
 457         unsigned char sha1[20];
 458         const char *head_ref;
 459         int flag;
 460
 461         if (loaded)
 462                 return;
 463         loaded = 1;
 464
 465         current_branch = NULL;
 466         head_ref = resolve_ref_unsafe("HEAD", 0, sha1, &flag);
 467         if (head_ref && (flag & REF_ISSYMREF) &&
 468             skip_prefix(head_ref, "refs/heads/", &head_ref)) {
 469                 current_branch = make_branch(head_ref, 0);
 470         }
 471         git_config(handle_config, NULL);
 472         alias_all_urls();
 473 }
 474
 475 /*
 476  * This function frees a refspec array.
 477  * Warning: code paths should be checked to ensure that the src
 478  *          and dst pointers are always freeable pointers as well
 479  *          as the refspec pointer itself.
 480  */
 481 static void free_refspecs(struct refspec *refspec, int nr_refspec)
 482 {
 483         int i;
 484
 485         if (!refspec)
 486                 return;
 487
 488         for (i = 0; i < nr_refspec; i++) {
 489                 free(refspec[i].src);
 490                 free(refspec[i].dst);
 491         }
 492         free(refspec);
 493 }
 494
 495 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 496 {
 497         int i;
 498         struct refspec *rs = xcalloc(nr_refspec, sizeof(*rs));
 499
 500         for (i = 0; i < nr_refspec; i++) {
 501                 size_t llen;
 502                 int is_glob;
 503                 const char *lhs, *rhs;
 504                 int flags;
 505
 506                 is_glob = 0;
 507
 508                 lhs = refspec[i];
 509                 if (*lhs == '+') {
 510                         rs[i].force = 1;
 511                         lhs++;
 512                 }
 513
 514                 rhs = strrchr(lhs, ':');
 515
 516                 /*
 517                  * Before going on, special case ":" (or "+:") as a refspec
 518                  * for pushing matching refs.
 519                  */
 520                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
 521                         rs[i].matching = 1;
 522                         continue;
 523                 }
 524
 525                 if (rhs) {
 526                         size_t rlen = strlen(++rhs);
 527                         is_glob = (1 <= rlen && strchr(rhs, '*'));
 528                         rs[i].dst = xstrndup(rhs, rlen);
 529                 }
 530
 531                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 532                 if (1 <= llen && memchr(lhs, '*', llen)) {
 533                         if ((rhs && !is_glob) || (!rhs && fetch))
 534                                 goto invalid;
 535                         is_glob = 1;
 536                 } else if (rhs && is_glob) {
 537                         goto invalid;
 538                 }
 539
 540                 rs[i].pattern = is_glob;
 541                 rs[i].src = xstrndup(lhs, llen);
 542                 flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
 543
 544                 if (fetch) {
 545                         unsigned char unused[40];
 546
 547                         /* LHS */
 548                         if (!*rs[i].src)
 549                                 ; /* empty is ok; it means "HEAD" */
 550                         else if (llen == 40 && !get_sha1_hex(rs[i].src, unused))
 551                                 rs[i].exact_sha1 = 1; /* ok */
 552                         else if (!check_refname_format(rs[i].src, flags))
 553                                 ; /* valid looking ref is ok */
 554                         else
 555                                 goto invalid;
 556                         /* RHS */
 557                         if (!rs[i].dst)
 558                                 ; /* missing is ok; it is the same as empty */
 559                         else if (!*rs[i].dst)
 560                                 ; /* empty is ok; it means "do not store" */
 561                         else if (!check_refname_format(rs[i].dst, flags))
 562                                 ; /* valid looking ref is ok */
 563                         else
 564                                 goto invalid;
 565                 } else {
 566                         /*
 567                          * LHS
 568                          * - empty is allowed; it means delete.
 569                          * - when wildcarded, it must be a valid looking ref.
 570                          * - otherwise, it must be an extended SHA-1, but
 571                          *   there is no existing way to validate this.
 572                          */
 573                         if (!*rs[i].src)
 574                                 ; /* empty is ok */
 575                         else if (is_glob) {
 576                                 if (check_refname_format(rs[i].src, flags))
 577                                         goto invalid;
 578                         }
 579                         else
 580                                 ; /* anything goes, for now */
 581                         /*
 582                          * RHS
 583                          * - missing is allowed, but LHS then must be a
 584                          *   valid looking ref.
 585                          * - empty is not allowed.
 586                          * - otherwise it must be a valid looking ref.
 587                          */
 588                         if (!rs[i].dst) {
 589                                 if (check_refname_format(rs[i].src, flags))
 590                                         goto invalid;
 591                         } else if (!*rs[i].dst) {
 592                                 goto invalid;
 593                         } else {
 594                                 if (check_refname_format(rs[i].dst, flags))
 595                                         goto invalid;
 596                         }
 597                 }
 598         }
 599         return rs;
 600
 601  invalid:
 602         if (verify) {
 603                 /*
 604                  * nr_refspec must be greater than zero and i must be valid
 605                  * since it is only possible to reach this point from within
 606                  * the for loop above.
 607                  */
 608                 free_refspecs(rs, i+1);
 609                 return NULL;
 610         }
 611         die("Invalid refspec '%s'", refspec[i]);
 612 }
 613
 614 int valid_fetch_refspec(const char *fetch_refspec_str)
 615 {
 616         struct refspec *refspec;
 617
 618         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
 619         free_refspecs(refspec, 1);
 620         return !!refspec;
 621 }
 622
 623 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 624 {
 625         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 626 }
 627
 628 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 629 {
 630         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 631 }
 632
 633 void free_refspec(int nr_refspec, struct refspec *refspec)
 634 {
 635         int i;
 636         for (i = 0; i < nr_refspec; i++) {
 637                 free(refspec[i].src);
 638                 free(refspec[i].dst);
 639         }
 640         free(refspec);
 641 }
 642
 643 static int valid_remote_nick(const char *name)
 644 {
 645         if (!name[0] || is_dot_or_dotdot(name))
 646                 return 0;
 647         return !strchr(name, '/'); /* no slash */
 648 }
 649
 650 const char *remote_for_branch(struct branch *branch, int *explicit)
 651 {
 652         if (branch && branch->remote_name) {
 653                 if (explicit)
 654                         *explicit = 1;
 655                 return branch->remote_name;
 656         }
 657         if (explicit)
 658                 *explicit = 0;
 659         return "origin";
 660 }
 661
 662 const char *pushremote_for_branch(struct branch *branch, int *explicit)
 663 {
 664         if (branch && branch->pushremote_name) {
 665                 if (explicit)
 666                         *explicit = 1;
 667                 return branch->pushremote_name;
 668         }
 669         if (pushremote_name) {
 670                 if (explicit)
 671                         *explicit = 1;
 672                 return pushremote_name;
 673         }
 674         return remote_for_branch(branch, explicit);
 675 }
 676
 677 static struct remote *remote_get_1(const char *name,
 678                                    const char *(*get_default)(struct branch *, int *))
 679 {
 680         struct remote *ret;
 681         int name_given = 0;
 682
 683         read_config();
 684
 685         if (name)
 686                 name_given = 1;
 687         else
 688                 name = get_default(current_branch, &name_given);
 689
 690         ret = make_remote(name, 0);
 691         if (valid_remote_nick(name)) {
 692                 if (!valid_remote(ret))
 693                         read_remotes_file(ret);
 694                 if (!valid_remote(ret))
 695                         read_branches_file(ret);
 696         }
 697         if (name_given && !valid_remote(ret))
 698                 add_url_alias(ret, name);
 699         if (!valid_remote(ret))
 700                 return NULL;
 701         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 702         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 703         return ret;
 704 }
 705
 706 struct remote *remote_get(const char *name)
 707 {
 708         return remote_get_1(name, remote_for_branch);
 709 }
 710
 711 struct remote *pushremote_get(const char *name)
 712 {
 713         return remote_get_1(name, pushremote_for_branch);
 714 }
 715
 716 int remote_is_configured(const char *name)
 717 {
 718         struct remotes_hash_key lookup;
 719         struct hashmap_entry lookup_entry;
 720         read_config();
 721
 722         init_remotes_hash();
 723         lookup.str = name;
 724         lookup.len = strlen(name);
 725         hashmap_entry_init(&lookup_entry, memhash(name, lookup.len));
 726
 727         return hashmap_get(&remotes_hash, &lookup_entry, &lookup) != NULL;
 728 }
 729
 730 int for_each_remote(each_remote_fn fn, void *priv)
 731 {
 732         int i, result = 0;
 733         read_config();
 734         for (i = 0; i < remotes_nr && !result; i++) {
 735                 struct remote *r = remotes[i];
 736                 if (!r)
 737                         continue;
 738                 if (!r->fetch)
 739                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 740                                                        r->fetch_refspec);
 741                 if (!r->push)
 742                         r->push = parse_push_refspec(r->push_refspec_nr,
 743                                                      r->push_refspec);
 744                 result = fn(r, priv);
 745         }
 746         return result;
 747 }
 748
 749 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
 750 {
 751         if (strcmp(ref1->name, ref2->name)) {
 752                 if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 753                     ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
 754                         die(_("Cannot fetch both %s and %s to %s"),
 755                             ref1->name, ref2->name, ref2->peer_ref->name);
 756                 } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 757                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 758                         warning(_("%s usually tracks %s, not %s"),
 759                                 ref2->peer_ref->name, ref2->name, ref1->name);
 760                 } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
 761                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 762                         die(_("%s tracks both %s and %s"),
 763                             ref2->peer_ref->name, ref1->name, ref2->name);
 764                 } else {
 765                         /*
 766                          * This last possibility doesn't occur because
 767                          * FETCH_HEAD_IGNORE entries always appear at
 768                          * the end of the list.
 769                          */
 770                         die(_("Internal error"));
 771                 }
 772         }
 773         free(ref2->peer_ref);
 774         free(ref2);
 775 }
 776
 777 struct ref *ref_remove_duplicates(struct ref *ref_map)
 778 {
 779         struct string_list refs = STRING_LIST_INIT_NODUP;
 780         struct ref *retval = NULL;
 781         struct ref **p = &retval;
 782
 783         while (ref_map) {
 784                 struct ref *ref = ref_map;
 785
 786                 ref_map = ref_map->next;
 787                 ref->next = NULL;
 788
 789                 if (!ref->peer_ref) {
 790                         *p = ref;
 791                         p = &ref->next;
 792                 } else {
 793                         struct string_list_item *item =
 794                                 string_list_insert(&refs, ref->peer_ref->name);
 795
 796                         if (item->util) {
 797                                 /* Entry already existed */
 798                                 handle_duplicate((struct ref *)item->util, ref);
 799                         } else {
 800                                 *p = ref;
 801                                 p = &ref->next;
 802                                 item->util = ref;
 803                         }
 804                 }
 805         }
 806
 807         string_list_clear(&refs, 0);
 808         return retval;
 809 }
 810
 811 int remote_has_url(struct remote *remote, const char *url)
 812 {
 813         int i;
 814         for (i = 0; i < remote->url_nr; i++) {
 815                 if (!strcmp(remote->url[i], url))
 816                         return 1;
 817         }
 818         return 0;
 819 }
 820
 821 static int match_name_with_pattern(const char *key, const char *name,
 822                                    const char *value, char **result)
 823 {
 824         const char *kstar = strchr(key, '*');
 825         size_t klen;
 826         size_t ksuffixlen;
 827         size_t namelen;
 828         int ret;
 829         if (!kstar)
 830                 die("Key '%s' of pattern had no '*'", key);
 831         klen = kstar - key;
 832         ksuffixlen = strlen(kstar + 1);
 833         namelen = strlen(name);
 834         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 835                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 836         if (ret && value) {
 837                 struct strbuf sb = STRBUF_INIT;
 838                 const char *vstar = strchr(value, '*');
 839                 if (!vstar)
 840                         die("Value '%s' of pattern has no '*'", value);
 841                 strbuf_add(&sb, value, vstar - value);
 842                 strbuf_add(&sb, name + klen, namelen - klen - ksuffixlen);
 843                 strbuf_addstr(&sb, vstar + 1);
 844                 *result = strbuf_detach(&sb, NULL);
 845         }
 846         return ret;
 847 }
 848
 849 static void query_refspecs_multiple(struct refspec *refs, int ref_count, struct refspec *query, struct string_list *results)
 850 {
 851         int i;
 852         int find_src = !query->src;
 853
 854         if (find_src && !query->dst)
 855                 error("query_refspecs_multiple: need either src or dst");
 856
 857         for (i = 0; i < ref_count; i++) {
 858                 struct refspec *refspec = &refs[i];
 859                 const char *key = find_src ? refspec->dst : refspec->src;
 860                 const char *value = find_src ? refspec->src : refspec->dst;
 861                 const char *needle = find_src ? query->dst : query->src;
 862                 char **result = find_src ? &query->src : &query->dst;
 863
 864                 if (!refspec->dst)
 865                         continue;
 866                 if (refspec->pattern) {
 867                         if (match_name_with_pattern(key, needle, value, result))
 868                                 string_list_append_nodup(results, *result);
 869                 } else if (!strcmp(needle, key)) {
 870                         string_list_append(results, value);
 871                 }
 872         }
 873 }
 874
 875 int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
 876 {
 877         int i;
 878         int find_src = !query->src;
 879         const char *needle = find_src ? query->dst : query->src;
 880         char **result = find_src ? &query->src : &query->dst;
 881
 882         if (find_src && !query->dst)
 883                 return error("query_refspecs: need either src or dst");
 884
 885         for (i = 0; i < ref_count; i++) {
 886                 struct refspec *refspec = &refs[i];
 887                 const char *key = find_src ? refspec->dst : refspec->src;
 888                 const char *value = find_src ? refspec->src : refspec->dst;
 889
 890                 if (!refspec->dst)
 891                         continue;
 892                 if (refspec->pattern) {
 893                         if (match_name_with_pattern(key, needle, value, result)) {
 894                                 query->force = refspec->force;
 895                                 return 0;
 896                         }
 897                 } else if (!strcmp(needle, key)) {
 898                         *result = xstrdup(value);
 899                         query->force = refspec->force;
 900                         return 0;
 901                 }
 902         }
 903         return -1;
 904 }
 905
 906 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 907                      const char *name)
 908 {
 909         struct refspec query;
 910
 911         memset(&query, 0, sizeof(struct refspec));
 912         query.src = (char *)name;
 913
 914         if (query_refspecs(refspecs, nr_refspec, &query))
 915                 return NULL;
 916
 917         return query.dst;
 918 }
 919
 920 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 921 {
 922         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
 923 }
 924
 925 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 926                 const char *name)
 927 {
 928         size_t len = strlen(name);
 929         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 930         memcpy(ref->name, prefix, prefixlen);
 931         memcpy(ref->name + prefixlen, name, len);
 932         return ref;
 933 }
 934
 935 struct ref *alloc_ref(const char *name)
 936 {
 937         return alloc_ref_with_prefix("", 0, name);
 938 }
 939
 940 struct ref *copy_ref(const struct ref *ref)
 941 {
 942         struct ref *cpy;
 943         size_t len;
 944         if (!ref)
 945                 return NULL;
 946         len = strlen(ref->name);
 947         cpy = xmalloc(sizeof(struct ref) + len + 1);
 948         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 949         cpy->next = NULL;
 950         cpy->symref = xstrdup_or_null(ref->symref);
 951         cpy->remote_status = xstrdup_or_null(ref->remote_status);
 952         cpy->peer_ref = copy_ref(ref->peer_ref);
 953         return cpy;
 954 }
 955
 956 struct ref *copy_ref_list(const struct ref *ref)
 957 {
 958         struct ref *ret = NULL;
 959         struct ref **tail = &ret;
 960         while (ref) {
 961                 *tail = copy_ref(ref);
 962                 ref = ref->next;
 963                 tail = &((*tail)->next);
 964         }
 965         return ret;
 966 }
 967
 968 static void free_ref(struct ref *ref)
 969 {
 970         if (!ref)
 971                 return;
 972         free_ref(ref->peer_ref);
 973         free(ref->remote_status);
 974         free(ref->symref);
 975         free(ref);
 976 }
 977
 978 void free_refs(struct ref *ref)
 979 {
 980         struct ref *next;
 981         while (ref) {
 982                 next = ref->next;
 983                 free_ref(ref);
 984                 ref = next;
 985         }
 986 }
 987
 988 int ref_compare_name(const void *va, const void *vb)
 989 {
 990         const struct ref *a = va, *b = vb;
 991         return strcmp(a->name, b->name);
 992 }
 993
 994 static void *ref_list_get_next(const void *a)
 995 {
 996         return ((const struct ref *)a)->next;
 997 }
 998
 999 static void ref_list_set_next(void *a, void *next)
1000 {
1001         ((struct ref *)a)->next = next;
1002 }
1003
1004 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
1005 {
1006         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
1007 }
1008
1009 int count_refspec_match(const char *pattern,
1010                         struct ref *refs,
1011                         struct ref **matched_ref)
1012 {
1013         int patlen = strlen(pattern);
1014         struct ref *matched_weak = NULL;
1015         struct ref *matched = NULL;
1016         int weak_match = 0;
1017         int match = 0;
1018
1019         for (weak_match = match = 0; refs; refs = refs->next) {
1020                 char *name = refs->name;
1021                 int namelen = strlen(name);
1022
1023                 if (!refname_match(pattern, name))
1024                         continue;
1025
1026                 /* A match is "weak" if it is with refs outside
1027                  * heads or tags, and did not specify the pattern
1028                  * in full (e.g. "refs/remotes/origin/master") or at
1029                  * least from the toplevel (e.g. "remotes/origin/master");
1030                  * otherwise "git push $URL master" would result in
1031                  * ambiguity between remotes/origin/master and heads/master
1032                  * at the remote site.
1033                  */
1034                 if (namelen != patlen &&
1035                     patlen != namelen - 5 &&
1036                     !starts_with(name, "refs/heads/") &&
1037                     !starts_with(name, "refs/tags/")) {
1038                         /* We want to catch the case where only weak
1039                          * matches are found and there are multiple
1040                          * matches, and where more than one strong
1041                          * matches are found, as ambiguous.  One
1042                          * strong match with zero or more weak matches
1043                          * are acceptable as a unique match.
1044                          */
1045                         matched_weak = refs;
1046                         weak_match++;
1047                 }
1048                 else {
1049                         matched = refs;
1050                         match++;
1051                 }
1052         }
1053         if (!matched) {
1054                 if (matched_ref)
1055                         *matched_ref = matched_weak;
1056                 return weak_match;
1057         }
1058         else {
1059                 if (matched_ref)
1060                         *matched_ref = matched;
1061                 return match;
1062         }
1063 }
1064
1065 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1066 {
1067         **tail = ref;
1068         while (ref->next)
1069                 ref = ref->next;
1070         *tail = &ref->next;
1071 }
1072
1073 static struct ref *alloc_delete_ref(void)
1074 {
1075         struct ref *ref = alloc_ref("(delete)");
1076         hashclr(ref->new_sha1);
1077         return ref;
1078 }
1079
1080 static int try_explicit_object_name(const char *name,
1081                                     struct ref **match)
1082 {
1083         unsigned char sha1[20];
1084
1085         if (!*name) {
1086                 if (match)
1087                         *match = alloc_delete_ref();
1088                 return 0;
1089         }
1090
1091         if (get_sha1(name, sha1))
1092                 return -1;
1093
1094         if (match) {
1095                 *match = alloc_ref(name);
1096                 hashcpy((*match)->new_sha1, sha1);
1097         }
1098         return 0;
1099 }
1100
1101 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1102 {
1103         struct ref *ret = alloc_ref(name);
1104         tail_link_ref(ret, tail);
1105         return ret;
1106 }
1107
1108 static char *guess_ref(const char *name, struct ref *peer)
1109 {
1110         struct strbuf buf = STRBUF_INIT;
1111         unsigned char sha1[20];
1112
1113         const char *r = resolve_ref_unsafe(peer->name, RESOLVE_REF_READING,
1114                                            sha1, NULL);
1115         if (!r)
1116                 return NULL;
1117
1118         if (starts_with(r, "refs/heads/"))
1119                 strbuf_addstr(&buf, "refs/heads/");
1120         else if (starts_with(r, "refs/tags/"))
1121                 strbuf_addstr(&buf, "refs/tags/");
1122         else
1123                 return NULL;
1124
1125         strbuf_addstr(&buf, name);
1126         return strbuf_detach(&buf, NULL);
1127 }
1128
1129 static int match_explicit_lhs(struct ref *src,
1130                               struct refspec *rs,
1131                               struct ref **match,
1132                               int *allocated_match)
1133 {
1134         switch (count_refspec_match(rs->src, src, match)) {
1135         case 1:
1136                 if (allocated_match)
1137                         *allocated_match = 0;
1138                 return 0;
1139         case 0:
1140                 /* The source could be in the get_sha1() format
1141                  * not a reference name.  :refs/other is a
1142                  * way to delete 'other' ref at the remote end.
1143                  */
1144                 if (try_explicit_object_name(rs->src, match) < 0)
1145                         return error("src refspec %s does not match any.", rs->src);
1146                 if (allocated_match)
1147                         *allocated_match = 1;
1148                 return 0;
1149         default:
1150                 return error("src refspec %s matches more than one.", rs->src);
1151         }
1152 }
1153
1154 static int match_explicit(struct ref *src, struct ref *dst,
1155                           struct ref ***dst_tail,
1156                           struct refspec *rs)
1157 {
1158         struct ref *matched_src, *matched_dst;
1159         int allocated_src;
1160
1161         const char *dst_value = rs->dst;
1162         char *dst_guess;
1163
1164         if (rs->pattern || rs->matching)
1165                 return 0;
1166
1167         matched_src = matched_dst = NULL;
1168         if (match_explicit_lhs(src, rs, &matched_src, &allocated_src) < 0)
1169                 return -1;
1170
1171         if (!dst_value) {
1172                 unsigned char sha1[20];
1173                 int flag;
1174
1175                 dst_value = resolve_ref_unsafe(matched_src->name,
1176                                                RESOLVE_REF_READING,
1177                                                sha1, &flag);
1178                 if (!dst_value ||
1179                     ((flag & REF_ISSYMREF) &&
1180                      !starts_with(dst_value, "refs/heads/")))
1181                         die("%s cannot be resolved to branch.",
1182                             matched_src->name);
1183         }
1184
1185         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1186         case 1:
1187                 break;
1188         case 0:
1189                 if (starts_with(dst_value, "refs/"))
1190                         matched_dst = make_linked_ref(dst_value, dst_tail);
1191                 else if (is_null_sha1(matched_src->new_sha1))
1192                         error("unable to delete '%s': remote ref does not exist",
1193                               dst_value);
1194                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1195                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1196                 else
1197                         error("unable to push to unqualified destination: %s\n"
1198                               "The destination refspec neither matches an "
1199                               "existing ref on the remote nor\n"
1200                               "begins with refs/, and we are unable to "
1201                               "guess a prefix based on the source ref.",
1202                               dst_value);
1203                 break;
1204         default:
1205                 matched_dst = NULL;
1206                 error("dst refspec %s matches more than one.",
1207                       dst_value);
1208                 break;
1209         }
1210         if (!matched_dst)
1211                 return -1;
1212         if (matched_dst->peer_ref)
1213                 return error("dst ref %s receives from more than one src.",
1214                       matched_dst->name);
1215         else {
1216                 matched_dst->peer_ref = allocated_src ?
1217                                         matched_src :
1218                                         copy_ref(matched_src);
1219                 matched_dst->force = rs->force;
1220         }
1221         return 0;
1222 }
1223
1224 static int match_explicit_refs(struct ref *src, struct ref *dst,
1225                                struct ref ***dst_tail, struct refspec *rs,
1226                                int rs_nr)
1227 {
1228         int i, errs;
1229         for (i = errs = 0; i < rs_nr; i++)
1230                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1231         return errs;
1232 }
1233
1234 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1235                 int send_mirror, int direction, const struct refspec **ret_pat)
1236 {
1237         const struct refspec *pat;
1238         char *name;
1239         int i;
1240         int matching_refs = -1;
1241         for (i = 0; i < rs_nr; i++) {
1242                 if (rs[i].matching &&
1243                     (matching_refs == -1 || rs[i].force)) {
1244                         matching_refs = i;
1245                         continue;
1246                 }
1247
1248                 if (rs[i].pattern) {
1249                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1250                         int match;
1251                         if (direction == FROM_SRC)
1252                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1253                         else
1254                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1255                         if (match) {
1256                                 matching_refs = i;
1257                                 break;
1258                         }
1259                 }
1260         }
1261         if (matching_refs == -1)
1262                 return NULL;
1263
1264         pat = rs + matching_refs;
1265         if (pat->matching) {
1266                 /*
1267                  * "matching refs"; traditionally we pushed everything
1268                  * including refs outside refs/heads/ hierarchy, but
1269                  * that does not make much sense these days.
1270                  */
1271                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1272                         return NULL;
1273                 name = xstrdup(ref->name);
1274         }
1275         if (ret_pat)
1276                 *ret_pat = pat;
1277         return name;
1278 }
1279
1280 static struct ref **tail_ref(struct ref **head)
1281 {
1282         struct ref **tail = head;
1283         while (*tail)
1284                 tail = &((*tail)->next);
1285         return tail;
1286 }
1287
1288 struct tips {
1289         struct commit **tip;
1290         int nr, alloc;
1291 };
1292
1293 static void add_to_tips(struct tips *tips, const unsigned char *sha1)
1294 {
1295         struct commit *commit;
1296
1297         if (is_null_sha1(sha1))
1298                 return;
1299         commit = lookup_commit_reference_gently(sha1, 1);
1300         if (!commit || (commit->object.flags & TMP_MARK))
1301                 return;
1302         commit->object.flags |= TMP_MARK;
1303         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1304         tips->tip[tips->nr++] = commit;
1305 }
1306
1307 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1308 {
1309         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1310         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1311         struct string_list_item *item;
1312         struct ref *ref;
1313         struct tips sent_tips;
1314
1315         /*
1316          * Collect everything we know they would have at the end of
1317          * this push, and collect all tags they have.
1318          */
1319         memset(&sent_tips, 0, sizeof(sent_tips));
1320         for (ref = *dst; ref; ref = ref->next) {
1321                 if (ref->peer_ref &&
1322                     !is_null_sha1(ref->peer_ref->new_sha1))
1323                         add_to_tips(&sent_tips, ref->peer_ref->new_sha1);
1324                 else
1325                         add_to_tips(&sent_tips, ref->old_sha1);
1326                 if (starts_with(ref->name, "refs/tags/"))
1327                         string_list_append(&dst_tag, ref->name);
1328         }
1329         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1330
1331         string_list_sort(&dst_tag);
1332
1333         /* Collect tags they do not have. */
1334         for (ref = src; ref; ref = ref->next) {
1335                 if (!starts_with(ref->name, "refs/tags/"))
1336                         continue; /* not a tag */
1337                 if (string_list_has_string(&dst_tag, ref->name))
1338                         continue; /* they already have it */
1339                 if (sha1_object_info(ref->new_sha1, NULL) != OBJ_TAG)
1340                         continue; /* be conservative */
1341                 item = string_list_append(&src_tag, ref->name);
1342                 item->util = ref;
1343         }
1344         string_list_clear(&dst_tag, 0);
1345
1346         /*
1347          * At this point, src_tag lists tags that are missing from
1348          * dst, and sent_tips lists the tips we are pushing or those
1349          * that we know they already have. An element in the src_tag
1350          * that is an ancestor of any of the sent_tips needs to be
1351          * sent to the other side.
1352          */
1353         if (sent_tips.nr) {
1354                 for_each_string_list_item(item, &src_tag) {
1355                         struct ref *ref = item->util;
1356                         struct ref *dst_ref;
1357                         struct commit *commit;
1358
1359                         if (is_null_sha1(ref->new_sha1))
1360                                 continue;
1361                         commit = lookup_commit_reference_gently(ref->new_sha1, 1);
1362                         if (!commit)
1363                                 /* not pushing a commit, which is not an error */
1364                                 continue;
1365
1366                         /*
1367                          * Is this tag, which they do not have, reachable from
1368                          * any of the commits we are sending?
1369                          */
1370                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1371                                 continue;
1372
1373                         /* Add it in */
1374                         dst_ref = make_linked_ref(ref->name, dst_tail);
1375                         hashcpy(dst_ref->new_sha1, ref->new_sha1);
1376                         dst_ref->peer_ref = copy_ref(ref);
1377                 }
1378         }
1379         string_list_clear(&src_tag, 0);
1380         free(sent_tips.tip);
1381 }
1382
1383 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1384 {
1385         for ( ; list; list = list->next)
1386                 if (!strcmp(list->name, name))
1387                         return (struct ref *)list;
1388         return NULL;
1389 }
1390
1391 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1392 {
1393         for ( ; ref; ref = ref->next)
1394                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1395
1396         string_list_sort(ref_index);
1397 }
1398
1399 /*
1400  * Given only the set of local refs, sanity-check the set of push
1401  * refspecs. We can't catch all errors that match_push_refs would,
1402  * but we can catch some errors early before even talking to the
1403  * remote side.
1404  */
1405 int check_push_refs(struct ref *src, int nr_refspec, const char **refspec_names)
1406 {
1407         struct refspec *refspec = parse_push_refspec(nr_refspec, refspec_names);
1408         int ret = 0;
1409         int i;
1410
1411         for (i = 0; i < nr_refspec; i++) {
1412                 struct refspec *rs = refspec + i;
1413
1414                 if (rs->pattern || rs->matching)
1415                         continue;
1416
1417                 ret |= match_explicit_lhs(src, rs, NULL, NULL);
1418         }
1419
1420         free_refspec(nr_refspec, refspec);
1421         return ret;
1422 }
1423
1424 /*
1425  * Given the set of refs the local repository has, the set of refs the
1426  * remote repository has, and the refspec used for push, determine
1427  * what remote refs we will update and with what value by setting
1428  * peer_ref (which object is being pushed) and force (if the push is
1429  * forced) in elements of "dst". The function may add new elements to
1430  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1431  */
1432 int match_push_refs(struct ref *src, struct ref **dst,
1433                     int nr_refspec, const char **refspec, int flags)
1434 {
1435         struct refspec *rs;
1436         int send_all = flags & MATCH_REFS_ALL;
1437         int send_mirror = flags & MATCH_REFS_MIRROR;
1438         int send_prune = flags & MATCH_REFS_PRUNE;
1439         int errs;
1440         static const char *default_refspec[] = { ":", NULL };
1441         struct ref *ref, **dst_tail = tail_ref(dst);
1442         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1443
1444         if (!nr_refspec) {
1445                 nr_refspec = 1;
1446                 refspec = default_refspec;
1447         }
1448         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1449         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1450
1451         /* pick the remainder */
1452         for (ref = src; ref; ref = ref->next) {
1453                 struct string_list_item *dst_item;
1454                 struct ref *dst_peer;
1455                 const struct refspec *pat = NULL;
1456                 char *dst_name;
1457
1458                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1459                 if (!dst_name)
1460                         continue;
1461
1462                 if (!dst_ref_index.nr)
1463                         prepare_ref_index(&dst_ref_index, *dst);
1464
1465                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1466                 dst_peer = dst_item ? dst_item->util : NULL;
1467                 if (dst_peer) {
1468                         if (dst_peer->peer_ref)
1469                                 /* We're already sending something to this ref. */
1470                                 goto free_name;
1471                 } else {
1472                         if (pat->matching && !(send_all || send_mirror))
1473                                 /*
1474                                  * Remote doesn't have it, and we have no
1475                                  * explicit pattern, and we don't have
1476                                  * --all or --mirror.
1477                                  */
1478                                 goto free_name;
1479
1480                         /* Create a new one and link it */
1481                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1482                         hashcpy(dst_peer->new_sha1, ref->new_sha1);
1483                         string_list_insert(&dst_ref_index,
1484                                 dst_peer->name)->util = dst_peer;
1485                 }
1486                 dst_peer->peer_ref = copy_ref(ref);
1487                 dst_peer->force = pat->force;
1488         free_name:
1489                 free(dst_name);
1490         }
1491
1492         string_list_clear(&dst_ref_index, 0);
1493
1494         if (flags & MATCH_REFS_FOLLOW_TAGS)
1495                 add_missing_tags(src, dst, &dst_tail);
1496
1497         if (send_prune) {
1498                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1499                 /* check for missing refs on the remote */
1500                 for (ref = *dst; ref; ref = ref->next) {
1501                         char *src_name;
1502
1503                         if (ref->peer_ref)
1504                                 /* We're already sending something to this ref. */
1505                                 continue;
1506
1507                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1508                         if (src_name) {
1509                                 if (!src_ref_index.nr)
1510                                         prepare_ref_index(&src_ref_index, src);
1511                                 if (!string_list_has_string(&src_ref_index,
1512                                             src_name))
1513                                         ref->peer_ref = alloc_delete_ref();
1514                                 free(src_name);
1515                         }
1516                 }
1517                 string_list_clear(&src_ref_index, 0);
1518         }
1519         if (errs)
1520                 return -1;
1521         return 0;
1522 }
1523
1524 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1525                              int force_update)
1526 {
1527         struct ref *ref;
1528
1529         for (ref = remote_refs; ref; ref = ref->next) {
1530                 int force_ref_update = ref->force || force_update;
1531                 int reject_reason = 0;
1532
1533                 if (ref->peer_ref)
1534                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1535                 else if (!send_mirror)
1536                         continue;
1537
1538                 ref->deletion = is_null_sha1(ref->new_sha1);
1539                 if (!ref->deletion &&
1540                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1541                         ref->status = REF_STATUS_UPTODATE;
1542                         continue;
1543                 }
1544
1545                 /*
1546                  * Bypass the usual "must fast-forward" check but
1547                  * replace it with a weaker "the old value must be
1548                  * this value we observed".  If the remote ref has
1549                  * moved and is now different from what we expect,
1550                  * reject any push.
1551                  *
1552                  * It also is an error if the user told us to check
1553                  * with the remote-tracking branch to find the value
1554                  * to expect, but we did not have such a tracking
1555                  * branch.
1556                  */
1557                 if (ref->expect_old_sha1) {
1558                         if (ref->expect_old_no_trackback ||
1559                             hashcmp(ref->old_sha1, ref->old_sha1_expect))
1560                                 reject_reason = REF_STATUS_REJECT_STALE;
1561                 }
1562
1563                 /*
1564                  * The usual "must fast-forward" rules.
1565                  *
1566                  * Decide whether an individual refspec A:B can be
1567                  * pushed.  The push will succeed if any of the
1568                  * following are true:
1569                  *
1570                  * (1) the remote reference B does not exist
1571                  *
1572                  * (2) the remote reference B is being removed (i.e.,
1573                  *     pushing :B where no source is specified)
1574                  *
1575                  * (3) the destination is not under refs/tags/, and
1576                  *     if the old and new value is a commit, the new
1577                  *     is a descendant of the old.
1578                  *
1579                  * (4) it is forced using the +A:B notation, or by
1580                  *     passing the --force argument
1581                  */
1582
1583                 else if (!ref->deletion && !is_null_sha1(ref->old_sha1)) {
1584                         if (starts_with(ref->name, "refs/tags/"))
1585                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1586                         else if (!has_sha1_file(ref->old_sha1))
1587                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1588                         else if (!lookup_commit_reference_gently(ref->old_sha1, 1) ||
1589                                  !lookup_commit_reference_gently(ref->new_sha1, 1))
1590                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1591                         else if (!ref_newer(ref->new_sha1, ref->old_sha1))
1592                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1593                 }
1594
1595                 /*
1596                  * "--force" will defeat any rejection implemented
1597                  * by the rules above.
1598                  */
1599                 if (!force_ref_update)
1600                         ref->status = reject_reason;
1601                 else if (reject_reason)
1602                         ref->forced_update = 1;
1603         }
1604 }
1605
1606 static void set_merge(struct branch *ret)
1607 {
1608         struct remote *remote;
1609         char *ref;
1610         unsigned char sha1[20];
1611         int i;
1612
1613         if (!ret)
1614                 return; /* no branch */
1615         if (ret->merge)
1616                 return; /* already run */
1617         if (!ret->remote_name || !ret->merge_nr) {
1618                 /*
1619                  * no merge config; let's make sure we don't confuse callers
1620                  * with a non-zero merge_nr but a NULL merge
1621                  */
1622                 ret->merge_nr = 0;
1623                 return;
1624         }
1625
1626         remote = remote_get(ret->remote_name);
1627
1628         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1629         for (i = 0; i < ret->merge_nr; i++) {
1630                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1631                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1632                 if (!remote_find_tracking(remote, ret->merge[i]) ||
1633                     strcmp(ret->remote_name, "."))
1634                         continue;
1635                 if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
1636                              sha1, &ref) == 1)
1637                         ret->merge[i]->dst = ref;
1638                 else
1639                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1640         }
1641 }
1642
1643 struct branch *branch_get(const char *name)
1644 {
1645         struct branch *ret;
1646
1647         read_config();
1648         if (!name || !*name || !strcmp(name, "HEAD"))
1649                 ret = current_branch;
1650         else
1651                 ret = make_branch(name, 0);
1652         set_merge(ret);
1653         return ret;
1654 }
1655
1656 int branch_has_merge_config(struct branch *branch)
1657 {
1658         return branch && !!branch->merge;
1659 }
1660
1661 int branch_merge_matches(struct branch *branch,
1662                                  int i,
1663                                  const char *refname)
1664 {
1665         if (!branch || i < 0 || i >= branch->merge_nr)
1666                 return 0;
1667         return refname_match(branch->merge[i]->src, refname);
1668 }
1669
1670 __attribute((format (printf,2,3)))
1671 static const char *error_buf(struct strbuf *err, const char *fmt, ...)
1672 {
1673         if (err) {
1674                 va_list ap;
1675                 va_start(ap, fmt);
1676                 strbuf_vaddf(err, fmt, ap);
1677                 va_end(ap);
1678         }
1679         return NULL;
1680 }
1681
1682 const char *branch_get_upstream(struct branch *branch, struct strbuf *err)
1683 {
1684         if (!branch)
1685                 return error_buf(err, _("HEAD does not point to a branch"));
1686
1687         if (!branch->merge || !branch->merge[0]) {
1688                 /*
1689                  * no merge config; is it because the user didn't define any,
1690                  * or because it is not a real branch, and get_branch
1691                  * auto-vivified it?
1692                  */
1693                 if (!ref_exists(branch->refname))
1694                         return error_buf(err, _("no such branch: '%s'"),
1695                                          branch->name);
1696                 return error_buf(err,
1697                                  _("no upstream configured for branch '%s'"),
1698                                  branch->name);
1699         }
1700
1701         if (!branch->merge[0]->dst)
1702                 return error_buf(err,
1703                                  _("upstream branch '%s' not stored as a remote-tracking branch"),
1704                                  branch->merge[0]->src);
1705
1706         return branch->merge[0]->dst;
1707 }
1708
1709 static const char *tracking_for_push_dest(struct remote *remote,
1710                                           const char *refname,
1711                                           struct strbuf *err)
1712 {
1713         char *ret;
1714
1715         ret = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
1716         if (!ret)
1717                 return error_buf(err,
1718                                  _("push destination '%s' on remote '%s' has no local tracking branch"),
1719                                  refname, remote->name);
1720         return ret;
1721 }
1722
1723 static const char *branch_get_push_1(struct branch *branch, struct strbuf *err)
1724 {
1725         struct remote *remote;
1726
1727         if (!branch)
1728                 return error_buf(err, _("HEAD does not point to a branch"));
1729
1730         remote = remote_get(pushremote_for_branch(branch, NULL));
1731         if (!remote)
1732                 return error_buf(err,
1733                                  _("branch '%s' has no remote for pushing"),
1734                                  branch->name);
1735
1736         if (remote->push_refspec_nr) {
1737                 char *dst;
1738                 const char *ret;
1739
1740                 dst = apply_refspecs(remote->push, remote->push_refspec_nr,
1741                                      branch->refname);
1742                 if (!dst)
1743                         return error_buf(err,
1744                                          _("push refspecs for '%s' do not include '%s'"),
1745                                          remote->name, branch->name);
1746
1747                 ret = tracking_for_push_dest(remote, dst, err);
1748                 free(dst);
1749                 return ret;
1750         }
1751
1752         if (remote->mirror)
1753                 return tracking_for_push_dest(remote, branch->refname, err);
1754
1755         switch (push_default) {
1756         case PUSH_DEFAULT_NOTHING:
1757                 return error_buf(err, _("push has no destination (push.default is 'nothing')"));
1758
1759         case PUSH_DEFAULT_MATCHING:
1760         case PUSH_DEFAULT_CURRENT:
1761                 return tracking_for_push_dest(remote, branch->refname, err);
1762
1763         case PUSH_DEFAULT_UPSTREAM:
1764                 return branch_get_upstream(branch, err);
1765
1766         case PUSH_DEFAULT_UNSPECIFIED:
1767         case PUSH_DEFAULT_SIMPLE:
1768                 {
1769                         const char *up, *cur;
1770
1771                         up = branch_get_upstream(branch, err);
1772                         if (!up)
1773                                 return NULL;
1774                         cur = tracking_for_push_dest(remote, branch->refname, err);
1775                         if (!cur)
1776                                 return NULL;
1777                         if (strcmp(cur, up))
1778                                 return error_buf(err,
1779                                                  _("cannot resolve 'simple' push to a single destination"));
1780                         return cur;
1781                 }
1782         }
1783
1784         die("BUG: unhandled push situation");
1785 }
1786
1787 const char *branch_get_push(struct branch *branch, struct strbuf *err)
1788 {
1789         if (!branch->push_tracking_ref)
1790                 branch->push_tracking_ref = branch_get_push_1(branch, err);
1791         return branch->push_tracking_ref;
1792 }
1793
1794 static int ignore_symref_update(const char *refname)
1795 {
1796         unsigned char sha1[20];
1797         int flag;
1798
1799         if (!resolve_ref_unsafe(refname, 0, sha1, &flag))
1800                 return 0; /* non-existing refs are OK */
1801         return (flag & REF_ISSYMREF);
1802 }
1803
1804 /*
1805  * Create and return a list of (struct ref) consisting of copies of
1806  * each remote_ref that matches refspec.  refspec must be a pattern.
1807  * Fill in the copies' peer_ref to describe the local tracking refs to
1808  * which they map.  Omit any references that would map to an existing
1809  * local symbolic ref.
1810  */
1811 static struct ref *get_expanded_map(const struct ref *remote_refs,
1812                                     const struct refspec *refspec)
1813 {
1814         const struct ref *ref;
1815         struct ref *ret = NULL;
1816         struct ref **tail = &ret;
1817
1818         for (ref = remote_refs; ref; ref = ref->next) {
1819                 char *expn_name = NULL;
1820
1821                 if (strchr(ref->name, '^'))
1822                         continue; /* a dereference item */
1823                 if (match_name_with_pattern(refspec->src, ref->name,
1824                                             refspec->dst, &expn_name) &&
1825                     !ignore_symref_update(expn_name)) {
1826                         struct ref *cpy = copy_ref(ref);
1827
1828                         cpy->peer_ref = alloc_ref(expn_name);
1829                         if (refspec->force)
1830                                 cpy->peer_ref->force = 1;
1831                         *tail = cpy;
1832                         tail = &cpy->next;
1833                 }
1834                 free(expn_name);
1835         }
1836
1837         return ret;
1838 }
1839
1840 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1841 {
1842         const struct ref *ref;
1843         for (ref = refs; ref; ref = ref->next) {
1844                 if (refname_match(name, ref->name))
1845                         return ref;
1846         }
1847         return NULL;
1848 }
1849
1850 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1851 {
1852         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1853
1854         if (!ref)
1855                 return NULL;
1856
1857         return copy_ref(ref);
1858 }
1859
1860 static struct ref *get_local_ref(const char *name)
1861 {
1862         if (!name || name[0] == '\0')
1863                 return NULL;
1864
1865         if (starts_with(name, "refs/"))
1866                 return alloc_ref(name);
1867
1868         if (starts_with(name, "heads/") ||
1869             starts_with(name, "tags/") ||
1870             starts_with(name, "remotes/"))
1871                 return alloc_ref_with_prefix("refs/", 5, name);
1872
1873         return alloc_ref_with_prefix("refs/heads/", 11, name);
1874 }
1875
1876 int get_fetch_map(const struct ref *remote_refs,
1877                   const struct refspec *refspec,
1878                   struct ref ***tail,
1879                   int missing_ok)
1880 {
1881         struct ref *ref_map, **rmp;
1882
1883         if (refspec->pattern) {
1884                 ref_map = get_expanded_map(remote_refs, refspec);
1885         } else {
1886                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1887
1888                 if (refspec->exact_sha1) {
1889                         ref_map = alloc_ref(name);
1890                         get_sha1_hex(name, ref_map->old_sha1);
1891                 } else {
1892                         ref_map = get_remote_ref(remote_refs, name);
1893                 }
1894                 if (!missing_ok && !ref_map)
1895                         die("Couldn't find remote ref %s", name);
1896                 if (ref_map) {
1897                         ref_map->peer_ref = get_local_ref(refspec->dst);
1898                         if (ref_map->peer_ref && refspec->force)
1899                                 ref_map->peer_ref->force = 1;
1900                 }
1901         }
1902
1903         for (rmp = &ref_map; *rmp; ) {
1904                 if ((*rmp)->peer_ref) {
1905                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1906                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1907                                 struct ref *ignore = *rmp;
1908                                 error("* Ignoring funny ref '%s' locally",
1909                                       (*rmp)->peer_ref->name);
1910                                 *rmp = (*rmp)->next;
1911                                 free(ignore->peer_ref);
1912                                 free(ignore);
1913                                 continue;
1914                         }
1915                 }
1916                 rmp = &((*rmp)->next);
1917         }
1918
1919         if (ref_map)
1920                 tail_link_ref(ref_map, tail);
1921
1922         return 0;
1923 }
1924
1925 int resolve_remote_symref(struct ref *ref, struct ref *list)
1926 {
1927         if (!ref->symref)
1928                 return 0;
1929         for (; list; list = list->next)
1930                 if (!strcmp(ref->symref, list->name)) {
1931                         hashcpy(ref->old_sha1, list->old_sha1);
1932                         return 0;
1933                 }
1934         return 1;
1935 }
1936
1937 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1938 {
1939         while (list) {
1940                 struct commit_list *temp = list;
1941                 temp->item->object.flags &= ~mark;
1942                 list = temp->next;
1943                 free(temp);
1944         }
1945 }
1946
1947 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1948 {
1949         struct object *o;
1950         struct commit *old, *new;
1951         struct commit_list *list, *used;
1952         int found = 0;
1953
1954         /*
1955          * Both new and old must be commit-ish and new is descendant of
1956          * old.  Otherwise we require --force.
1957          */
1958         o = deref_tag(parse_object(old_sha1), NULL, 0);
1959         if (!o || o->type != OBJ_COMMIT)
1960                 return 0;
1961         old = (struct commit *) o;
1962
1963         o = deref_tag(parse_object(new_sha1), NULL, 0);
1964         if (!o || o->type != OBJ_COMMIT)
1965                 return 0;
1966         new = (struct commit *) o;
1967
1968         if (parse_commit(new) < 0)
1969                 return 0;
1970
1971         used = list = NULL;
1972         commit_list_insert(new, &list);
1973         while (list) {
1974                 new = pop_most_recent_commit(&list, TMP_MARK);
1975                 commit_list_insert(new, &used);
1976                 if (new == old) {
1977                         found = 1;
1978                         break;
1979                 }
1980         }
1981         unmark_and_free(list, TMP_MARK);
1982         unmark_and_free(used, TMP_MARK);
1983         return found;
1984 }
1985
1986 /*
1987  * Compare a branch with its upstream, and save their differences (number
1988  * of commits) in *num_ours and *num_theirs. The name of the upstream branch
1989  * (or NULL if no upstream is defined) is returned via *upstream_name, if it
1990  * is not itself NULL.
1991  *
1992  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
1993  * upstream defined, or ref does not exist), 0 otherwise.
1994  */
1995 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
1996                        const char **upstream_name)
1997 {
1998         unsigned char sha1[20];
1999         struct commit *ours, *theirs;
2000         char symmetric[84];
2001         struct rev_info revs;
2002         const char *rev_argv[10], *base;
2003         int rev_argc;
2004
2005         /* Cannot stat unless we are marked to build on top of somebody else. */
2006         base = branch_get_upstream(branch, NULL);
2007         if (upstream_name)
2008                 *upstream_name = base;
2009         if (!base)
2010                 return -1;
2011
2012         /* Cannot stat if what we used to build on no longer exists */
2013         if (read_ref(base, sha1))
2014                 return -1;
2015         theirs = lookup_commit_reference(sha1);
2016         if (!theirs)
2017                 return -1;
2018
2019         if (read_ref(branch->refname, sha1))
2020                 return -1;
2021         ours = lookup_commit_reference(sha1);
2022         if (!ours)
2023                 return -1;
2024
2025         /* are we the same? */
2026         if (theirs == ours) {
2027                 *num_theirs = *num_ours = 0;
2028                 return 0;
2029         }
2030
2031         /* Run "rev-list --left-right ours...theirs" internally... */
2032         rev_argc = 0;
2033         rev_argv[rev_argc++] = NULL;
2034         rev_argv[rev_argc++] = "--left-right";
2035         rev_argv[rev_argc++] = symmetric;
2036         rev_argv[rev_argc++] = "--";
2037         rev_argv[rev_argc] = NULL;
2038
2039         strcpy(symmetric, sha1_to_hex(ours->object.sha1));
2040         strcpy(symmetric + 40, "...");
2041         strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
2042
2043         init_revisions(&revs, NULL);
2044         setup_revisions(rev_argc, rev_argv, &revs, NULL);
2045         if (prepare_revision_walk(&revs))
2046                 die("revision walk setup failed");
2047
2048         /* ... and count the commits on each side. */
2049         *num_ours = 0;
2050         *num_theirs = 0;
2051         while (1) {
2052                 struct commit *c = get_revision(&revs);
2053                 if (!c)
2054                         break;
2055                 if (c->object.flags & SYMMETRIC_LEFT)
2056                         (*num_ours)++;
2057                 else
2058                         (*num_theirs)++;
2059         }
2060
2061         /* clear object flags smudged by the above traversal */
2062         clear_commit_marks(ours, ALL_REV_FLAGS);
2063         clear_commit_marks(theirs, ALL_REV_FLAGS);
2064         return 0;
2065 }
2066
2067 /*
2068  * Return true when there is anything to report, otherwise false.
2069  */
2070 int format_tracking_info(struct branch *branch, struct strbuf *sb)
2071 {
2072         int ours, theirs;
2073         const char *full_base;
2074         char *base;
2075         int upstream_is_gone = 0;
2076
2077         if (stat_tracking_info(branch, &ours, &theirs, &full_base) < 0) {
2078                 if (!full_base)
2079                         return 0;
2080                 upstream_is_gone = 1;
2081         }
2082
2083         base = shorten_unambiguous_ref(full_base, 0);
2084         if (upstream_is_gone) {
2085                 strbuf_addf(sb,
2086                         _("Your branch is based on '%s', but the upstream is gone.\n"),
2087                         base);
2088                 if (advice_status_hints)
2089                         strbuf_addf(sb,
2090                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
2091         } else if (!ours && !theirs) {
2092                 strbuf_addf(sb,
2093                         _("Your branch is up-to-date with '%s'.\n"),
2094                         base);
2095         } else if (!theirs) {
2096                 strbuf_addf(sb,
2097                         Q_("Your branch is ahead of '%s' by %d commit.\n",
2098                            "Your branch is ahead of '%s' by %d commits.\n",
2099                            ours),
2100                         base, ours);
2101                 if (advice_status_hints)
2102                         strbuf_addf(sb,
2103                                 _("  (use \"git push\" to publish your local commits)\n"));
2104         } else if (!ours) {
2105                 strbuf_addf(sb,
2106                         Q_("Your branch is behind '%s' by %d commit, "
2107                                "and can be fast-forwarded.\n",
2108                            "Your branch is behind '%s' by %d commits, "
2109                                "and can be fast-forwarded.\n",
2110                            theirs),
2111                         base, theirs);
2112                 if (advice_status_hints)
2113                         strbuf_addf(sb,
2114                                 _("  (use \"git pull\" to update your local branch)\n"));
2115         } else {
2116                 strbuf_addf(sb,
2117                         Q_("Your branch and '%s' have diverged,\n"
2118                                "and have %d and %d different commit each, "
2119                                "respectively.\n",
2120                            "Your branch and '%s' have diverged,\n"
2121                                "and have %d and %d different commits each, "
2122                                "respectively.\n",
2123                            theirs),
2124                         base, ours, theirs);
2125                 if (advice_status_hints)
2126                         strbuf_addf(sb,
2127                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
2128         }
2129         free(base);
2130         return 1;
2131 }
2132
2133 static int one_local_ref(const char *refname, const struct object_id *oid,
2134                          int flag, void *cb_data)
2135 {
2136         struct ref ***local_tail = cb_data;
2137         struct ref *ref;
2138         int len;
2139
2140         /* we already know it starts with refs/ to get here */
2141         if (check_refname_format(refname + 5, 0))
2142                 return 0;
2143
2144         len = strlen(refname) + 1;
2145         ref = xcalloc(1, sizeof(*ref) + len);
2146         hashcpy(ref->new_sha1, oid->hash);
2147         memcpy(ref->name, refname, len);
2148         **local_tail = ref;
2149         *local_tail = &ref->next;
2150         return 0;
2151 }
2152
2153 struct ref *get_local_heads(void)
2154 {
2155         struct ref *local_refs = NULL, **local_tail = &local_refs;
2156
2157         for_each_ref(one_local_ref, &local_tail);
2158         return local_refs;
2159 }
2160
2161 struct ref *guess_remote_head(const struct ref *head,
2162                               const struct ref *refs,
2163                               int all)
2164 {
2165         const struct ref *r;
2166         struct ref *list = NULL;
2167         struct ref **tail = &list;
2168
2169         if (!head)
2170                 return NULL;
2171
2172         /*
2173          * Some transports support directly peeking at
2174          * where HEAD points; if that is the case, then
2175          * we don't have to guess.
2176          */
2177         if (head->symref)
2178                 return copy_ref(find_ref_by_name(refs, head->symref));
2179
2180         /* If refs/heads/master could be right, it is. */
2181         if (!all) {
2182                 r = find_ref_by_name(refs, "refs/heads/master");
2183                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
2184                         return copy_ref(r);
2185         }
2186
2187         /* Look for another ref that points there */
2188         for (r = refs; r; r = r->next) {
2189                 if (r != head &&
2190                     starts_with(r->name, "refs/heads/") &&
2191                     !hashcmp(r->old_sha1, head->old_sha1)) {
2192                         *tail = copy_ref(r);
2193                         tail = &((*tail)->next);
2194                         if (!all)
2195                                 break;
2196                 }
2197         }
2198
2199         return list;
2200 }
2201
2202 struct stale_heads_info {
2203         struct string_list *ref_names;
2204         struct ref **stale_refs_tail;
2205         struct refspec *refs;
2206         int ref_count;
2207 };
2208
2209 static int get_stale_heads_cb(const char *refname, const struct object_id *oid,
2210                               int flags, void *cb_data)
2211 {
2212         struct stale_heads_info *info = cb_data;
2213         struct string_list matches = STRING_LIST_INIT_DUP;
2214         struct refspec query;
2215         int i, stale = 1;
2216         memset(&query, 0, sizeof(struct refspec));
2217         query.dst = (char *)refname;
2218
2219         query_refspecs_multiple(info->refs, info->ref_count, &query, &matches);
2220         if (matches.nr == 0)
2221                 goto clean_exit; /* No matches */
2222
2223         /*
2224          * If we did find a suitable refspec and it's not a symref and
2225          * it's not in the list of refs that currently exist in that
2226          * remote, we consider it to be stale. In order to deal with
2227          * overlapping refspecs, we need to go over all of the
2228          * matching refs.
2229          */
2230         if (flags & REF_ISSYMREF)
2231                 goto clean_exit;
2232
2233         for (i = 0; stale && i < matches.nr; i++)
2234                 if (string_list_has_string(info->ref_names, matches.items[i].string))
2235                         stale = 0;
2236
2237         if (stale) {
2238                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2239                 hashcpy(ref->new_sha1, oid->hash);
2240         }
2241
2242 clean_exit:
2243         string_list_clear(&matches, 0);
2244         return 0;
2245 }
2246
2247 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
2248 {
2249         struct ref *ref, *stale_refs = NULL;
2250         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2251         struct stale_heads_info info;
2252
2253         info.ref_names = &ref_names;
2254         info.stale_refs_tail = &stale_refs;
2255         info.refs = refs;
2256         info.ref_count = ref_count;
2257         for (ref = fetch_map; ref; ref = ref->next)
2258                 string_list_append(&ref_names, ref->name);
2259         string_list_sort(&ref_names);
2260         for_each_ref(get_stale_heads_cb, &info);
2261         string_list_clear(&ref_names, 0);
2262         return stale_refs;
2263 }
2264
2265 /*
2266  * Compare-and-swap
2267  */
2268 static void clear_cas_option(struct push_cas_option *cas)
2269 {
2270         int i;
2271
2272         for (i = 0; i < cas->nr; i++)
2273                 free(cas->entry[i].refname);
2274         free(cas->entry);
2275         memset(cas, 0, sizeof(*cas));
2276 }
2277
2278 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2279                                       const char *refname,
2280                                       size_t refnamelen)
2281 {
2282         struct push_cas *entry;
2283         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2284         entry = &cas->entry[cas->nr++];
2285         memset(entry, 0, sizeof(*entry));
2286         entry->refname = xmemdupz(refname, refnamelen);
2287         return entry;
2288 }
2289
2290 int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2291 {
2292         const char *colon;
2293         struct push_cas *entry;
2294
2295         if (unset) {
2296                 /* "--no-<option>" */
2297                 clear_cas_option(cas);
2298                 return 0;
2299         }
2300
2301         if (!arg) {
2302                 /* just "--<option>" */
2303                 cas->use_tracking_for_rest = 1;
2304                 return 0;
2305         }
2306
2307         /* "--<option>=refname" or "--<option>=refname:value" */
2308         colon = strchrnul(arg, ':');
2309         entry = add_cas_entry(cas, arg, colon - arg);
2310         if (!*colon)
2311                 entry->use_tracking = 1;
2312         else if (get_sha1(colon + 1, entry->expect))
2313                 return error("cannot parse expected object name '%s'", colon + 1);
2314         return 0;
2315 }
2316
2317 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2318 {
2319         return parse_push_cas_option(opt->value, arg, unset);
2320 }
2321
2322 int is_empty_cas(const struct push_cas_option *cas)
2323 {
2324         return !cas->use_tracking_for_rest && !cas->nr;
2325 }
2326
2327 /*
2328  * Look at remote.fetch refspec and see if we have a remote
2329  * tracking branch for the refname there.  Fill its current
2330  * value in sha1[].
2331  * If we cannot do so, return negative to signal an error.
2332  */
2333 static int remote_tracking(struct remote *remote, const char *refname,
2334                            unsigned char sha1[20])
2335 {
2336         char *dst;
2337
2338         dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
2339         if (!dst)
2340                 return -1; /* no tracking ref for refname at remote */
2341         if (read_ref(dst, sha1))
2342                 return -1; /* we know what the tracking ref is but we cannot read it */
2343         return 0;
2344 }
2345
2346 static void apply_cas(struct push_cas_option *cas,
2347                       struct remote *remote,
2348                       struct ref *ref)
2349 {
2350         int i;
2351
2352         /* Find an explicit --<option>=<name>[:<value>] entry */
2353         for (i = 0; i < cas->nr; i++) {
2354                 struct push_cas *entry = &cas->entry[i];
2355                 if (!refname_match(entry->refname, ref->name))
2356                         continue;
2357                 ref->expect_old_sha1 = 1;
2358                 if (!entry->use_tracking)
2359                         hashcpy(ref->old_sha1_expect, cas->entry[i].expect);
2360                 else if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2361                         ref->expect_old_no_trackback = 1;
2362                 return;
2363         }
2364
2365         /* Are we using "--<option>" to cover all? */
2366         if (!cas->use_tracking_for_rest)
2367                 return;
2368
2369         ref->expect_old_sha1 = 1;
2370         if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2371                 ref->expect_old_no_trackback = 1;
2372 }
2373
2374 void apply_push_cas(struct push_cas_option *cas,
2375                     struct remote *remote,
2376                     struct ref *remote_refs)
2377 {
2378         struct ref *ref;
2379         for (ref = remote_refs; ref; ref = ref->next)
2380                 apply_cas(cas, remote, ref);
2381 }