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 #include "argv-array.h"
  12
  13 enum map_direction { FROM_SRC, FROM_DST };
  14
  15 static struct refspec s_tag_refspec = {
  16         0,
  17         1,
  18         0,
  19         0,
  20         "refs/tags/*",
  21         "refs/tags/*"
  22 };
  23
  24 const struct refspec *tag_refspec = &s_tag_refspec;
  25
  26 struct counted_string {
  27         size_t len;
  28         const char *s;
  29 };
  30 struct rewrite {
  31         const char *base;
  32         size_t baselen;
  33         struct counted_string *instead_of;
  34         int instead_of_nr;
  35         int instead_of_alloc;
  36 };
  37 struct rewrites {
  38         struct rewrite **rewrite;
  39         int rewrite_alloc;
  40         int rewrite_nr;
  41 };
  42
  43 static struct remote **remotes;
  44 static int remotes_alloc;
  45 static int remotes_nr;
  46 static struct hashmap remotes_hash;
  47
  48 static struct branch **branches;
  49 static int branches_alloc;
  50 static int branches_nr;
  51
  52 static struct branch *current_branch;
  53 static const char *pushremote_name;
  54
  55 static struct rewrites rewrites;
  56 static struct rewrites rewrites_push;
  57
  58 static int valid_remote(const struct remote *remote)
  59 {
  60         return (!!remote->url) || (!!remote->foreign_vcs);
  61 }
  62
  63 static const char *alias_url(const char *url, struct rewrites *r)
  64 {
  65         int i, j;
  66         struct counted_string *longest;
  67         int longest_i;
  68
  69         longest = NULL;
  70         longest_i = -1;
  71         for (i = 0; i < r->rewrite_nr; i++) {
  72                 if (!r->rewrite[i])
  73                         continue;
  74                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  75                         if (starts_with(url, r->rewrite[i]->instead_of[j].s) &&
  76                             (!longest ||
  77                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  78                                 longest = &(r->rewrite[i]->instead_of[j]);
  79                                 longest_i = i;
  80                         }
  81                 }
  82         }
  83         if (!longest)
  84                 return url;
  85
  86         return xstrfmt("%s%s", r->rewrite[longest_i]->base, url + longest->len);
  87 }
  88
  89 static void add_push_refspec(struct remote *remote, const char *ref)
  90 {
  91         ALLOC_GROW(remote->push_refspec,
  92                    remote->push_refspec_nr + 1,
  93                    remote->push_refspec_alloc);
  94         remote->push_refspec[remote->push_refspec_nr++] = ref;
  95 }
  96
  97 static void add_fetch_refspec(struct remote *remote, const char *ref)
  98 {
  99         ALLOC_GROW(remote->fetch_refspec,
 100                    remote->fetch_refspec_nr + 1,
 101                    remote->fetch_refspec_alloc);
 102         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
 103 }
 104
 105 static void add_url(struct remote *remote, const char *url)
 106 {
 107         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
 108         remote->url[remote->url_nr++] = url;
 109 }
 110
 111 static void add_pushurl(struct remote *remote, const char *pushurl)
 112 {
 113         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
 114         remote->pushurl[remote->pushurl_nr++] = pushurl;
 115 }
 116
 117 static void add_pushurl_alias(struct remote *remote, const char *url)
 118 {
 119         const char *pushurl = alias_url(url, &rewrites_push);
 120         if (pushurl != url)
 121                 add_pushurl(remote, pushurl);
 122 }
 123
 124 static void add_url_alias(struct remote *remote, const char *url)
 125 {
 126         add_url(remote, alias_url(url, &rewrites));
 127         add_pushurl_alias(remote, url);
 128 }
 129
 130 struct remotes_hash_key {
 131         const char *str;
 132         int len;
 133 };
 134
 135 static int remotes_hash_cmp(const struct remote *a, const struct remote *b, const struct remotes_hash_key *key)
 136 {
 137         if (key)
 138                 return strncmp(a->name, key->str, key->len) || a->name[key->len];
 139         else
 140                 return strcmp(a->name, b->name);
 141 }
 142
 143 static inline void init_remotes_hash(void)
 144 {
 145         if (!remotes_hash.cmpfn)
 146                 hashmap_init(&remotes_hash, (hashmap_cmp_fn)remotes_hash_cmp, 0);
 147 }
 148
 149 static struct remote *make_remote(const char *name, int len)
 150 {
 151         struct remote *ret, *replaced;
 152         struct remotes_hash_key lookup;
 153         struct hashmap_entry lookup_entry;
 154
 155         if (!len)
 156                 len = strlen(name);
 157
 158         init_remotes_hash();
 159         lookup.str = name;
 160         lookup.len = len;
 161         hashmap_entry_init(&lookup_entry, memhash(name, len));
 162
 163         if ((ret = hashmap_get(&remotes_hash, &lookup_entry, &lookup)) != NULL)
 164                 return ret;
 165
 166         ret = xcalloc(1, sizeof(struct remote));
 167         ret->prune = -1;  /* unspecified */
 168         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 169         remotes[remotes_nr++] = ret;
 170         ret->name = xstrndup(name, len);
 171
 172         hashmap_entry_init(ret, lookup_entry.hash);
 173         replaced = hashmap_put(&remotes_hash, ret);
 174         assert(replaced == NULL);  /* no previous entry overwritten */
 175         return ret;
 176 }
 177
 178 static void add_merge(struct branch *branch, const char *name)
 179 {
 180         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 181                    branch->merge_alloc);
 182         branch->merge_name[branch->merge_nr++] = name;
 183 }
 184
 185 static struct branch *make_branch(const char *name, int len)
 186 {
 187         struct branch *ret;
 188         int i;
 189
 190         for (i = 0; i < branches_nr; i++) {
 191                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 192                            !branches[i]->name[len]) :
 193                     !strcmp(name, branches[i]->name))
 194                         return branches[i];
 195         }
 196
 197         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 198         ret = xcalloc(1, sizeof(struct branch));
 199         branches[branches_nr++] = ret;
 200         if (len)
 201                 ret->name = xstrndup(name, len);
 202         else
 203                 ret->name = xstrdup(name);
 204         ret->refname = xstrfmt("refs/heads/%s", ret->name);
 205
 206         return ret;
 207 }
 208
 209 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 210 {
 211         struct rewrite *ret;
 212         int i;
 213
 214         for (i = 0; i < r->rewrite_nr; i++) {
 215                 if (len
 216                     ? (len == r->rewrite[i]->baselen &&
 217                        !strncmp(base, r->rewrite[i]->base, len))
 218                     : !strcmp(base, r->rewrite[i]->base))
 219                         return r->rewrite[i];
 220         }
 221
 222         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 223         ret = xcalloc(1, sizeof(struct rewrite));
 224         r->rewrite[r->rewrite_nr++] = ret;
 225         if (len) {
 226                 ret->base = xstrndup(base, len);
 227                 ret->baselen = len;
 228         }
 229         else {
 230                 ret->base = xstrdup(base);
 231                 ret->baselen = strlen(base);
 232         }
 233         return ret;
 234 }
 235
 236 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 237 {
 238         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 239         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 240         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 241         rewrite->instead_of_nr++;
 242 }
 243
 244 static const char *skip_spaces(const char *s)
 245 {
 246         while (isspace(*s))
 247                 s++;
 248         return s;
 249 }
 250
 251 static void read_remotes_file(struct remote *remote)
 252 {
 253         struct strbuf buf = STRBUF_INIT;
 254         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 255
 256         if (!f)
 257                 return;
 258         remote->origin = REMOTE_REMOTES;
 259         while (strbuf_getline(&buf, f, '\n') != EOF) {
 260                 const char *v;
 261
 262                 strbuf_rtrim(&buf);
 263
 264                 if (skip_prefix(buf.buf, "URL:", &v))
 265                         add_url_alias(remote, xstrdup(skip_spaces(v)));
 266                 else if (skip_prefix(buf.buf, "Push:", &v))
 267                         add_push_refspec(remote, xstrdup(skip_spaces(v)));
 268                 else if (skip_prefix(buf.buf, "Pull:", &v))
 269                         add_fetch_refspec(remote, xstrdup(skip_spaces(v)));
 270         }
 271         strbuf_release(&buf);
 272         fclose(f);
 273 }
 274
 275 static void read_branches_file(struct remote *remote)
 276 {
 277         char *frag;
 278         struct strbuf buf = STRBUF_INIT;
 279         FILE *f = fopen(git_path("branches/%s", remote->name), "r");
 280
 281         if (!f)
 282                 return;
 283
 284         strbuf_getline(&buf, f, '\n');
 285         strbuf_trim(&buf);
 286         if (!buf.len) {
 287                 strbuf_release(&buf);
 288                 return;
 289         }
 290
 291         remote->origin = REMOTE_BRANCHES;
 292
 293         /*
 294          * The branches file would have URL and optionally
 295          * #branch specified.  The "master" (or specified) branch is
 296          * fetched and stored in the local branch matching the
 297          * remote name.
 298          */
 299         frag = strchr(buf.buf, '#');
 300         if (frag)
 301                 *(frag++) = '\0';
 302         else
 303                 frag = "master";
 304
 305         add_url_alias(remote, strbuf_detach(&buf, NULL));
 306         add_fetch_refspec(remote, xstrfmt("refs/heads/%s:refs/heads/%s",
 307                                           frag, remote->name));
 308
 309         /*
 310          * Cogito compatible push: push current HEAD to remote #branch
 311          * (master if missing)
 312          */
 313         add_push_refspec(remote, xstrfmt("HEAD:refs/heads/%s", frag));
 314         remote->fetch_tags = 1; /* always auto-follow */
 315 }
 316
 317 static int handle_config(const char *key, const char *value, void *cb)
 318 {
 319         const char *name;
 320         const char *subkey;
 321         struct remote *remote;
 322         struct branch *branch;
 323         if (starts_with(key, "branch.")) {
 324                 name = key + 7;
 325                 subkey = strrchr(name, '.');
 326                 if (!subkey)
 327                         return 0;
 328                 branch = make_branch(name, subkey - name);
 329                 if (!strcmp(subkey, ".remote")) {
 330                         return git_config_string(&branch->remote_name, key, value);
 331                 } else if (!strcmp(subkey, ".pushremote")) {
 332                         return git_config_string(&branch->pushremote_name, key, value);
 333                 } else if (!strcmp(subkey, ".merge")) {
 334                         if (!value)
 335                                 return config_error_nonbool(key);
 336                         add_merge(branch, xstrdup(value));
 337                 }
 338                 return 0;
 339         }
 340         if (starts_with(key, "url.")) {
 341                 struct rewrite *rewrite;
 342                 name = key + 4;
 343                 subkey = strrchr(name, '.');
 344                 if (!subkey)
 345                         return 0;
 346                 if (!strcmp(subkey, ".insteadof")) {
 347                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 348                         if (!value)
 349                                 return config_error_nonbool(key);
 350                         add_instead_of(rewrite, xstrdup(value));
 351                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 352                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 353                         if (!value)
 354                                 return config_error_nonbool(key);
 355                         add_instead_of(rewrite, xstrdup(value));
 356                 }
 357         }
 358
 359         if (!starts_with(key,  "remote."))
 360                 return 0;
 361         name = key + 7;
 362
 363         /* Handle remote.* variables */
 364         if (!strcmp(name, "pushdefault"))
 365                 return git_config_string(&pushremote_name, key, value);
 366
 367         /* Handle remote.<name>.* variables */
 368         if (*name == '/') {
 369                 warning("Config remote shorthand cannot begin with '/': %s",
 370                         name);
 371                 return 0;
 372         }
 373         subkey = strrchr(name, '.');
 374         if (!subkey)
 375                 return 0;
 376         remote = make_remote(name, subkey - name);
 377         remote->origin = REMOTE_CONFIG;
 378         if (!strcmp(subkey, ".mirror"))
 379                 remote->mirror = git_config_bool(key, value);
 380         else if (!strcmp(subkey, ".skipdefaultupdate"))
 381                 remote->skip_default_update = git_config_bool(key, value);
 382         else if (!strcmp(subkey, ".skipfetchall"))
 383                 remote->skip_default_update = git_config_bool(key, value);
 384         else if (!strcmp(subkey, ".prune"))
 385                 remote->prune = git_config_bool(key, value);
 386         else if (!strcmp(subkey, ".url")) {
 387                 const char *v;
 388                 if (git_config_string(&v, key, value))
 389                         return -1;
 390                 add_url(remote, v);
 391         } else if (!strcmp(subkey, ".pushurl")) {
 392                 const char *v;
 393                 if (git_config_string(&v, key, value))
 394                         return -1;
 395                 add_pushurl(remote, v);
 396         } else if (!strcmp(subkey, ".push")) {
 397                 const char *v;
 398                 if (git_config_string(&v, key, value))
 399                         return -1;
 400                 add_push_refspec(remote, v);
 401         } else if (!strcmp(subkey, ".fetch")) {
 402                 const char *v;
 403                 if (git_config_string(&v, key, value))
 404                         return -1;
 405                 add_fetch_refspec(remote, v);
 406         } else if (!strcmp(subkey, ".receivepack")) {
 407                 const char *v;
 408                 if (git_config_string(&v, key, value))
 409                         return -1;
 410                 if (!remote->receivepack)
 411                         remote->receivepack = v;
 412                 else
 413                         error("more than one receivepack given, using the first");
 414         } else if (!strcmp(subkey, ".uploadpack")) {
 415                 const char *v;
 416                 if (git_config_string(&v, key, value))
 417                         return -1;
 418                 if (!remote->uploadpack)
 419                         remote->uploadpack = v;
 420                 else
 421                         error("more than one uploadpack given, using the first");
 422         } else if (!strcmp(subkey, ".tagopt")) {
 423                 if (!strcmp(value, "--no-tags"))
 424                         remote->fetch_tags = -1;
 425                 else if (!strcmp(value, "--tags"))
 426                         remote->fetch_tags = 2;
 427         } else if (!strcmp(subkey, ".proxy")) {
 428                 return git_config_string((const char **)&remote->http_proxy,
 429                                          key, value);
 430         } else if (!strcmp(subkey, ".vcs")) {
 431                 return git_config_string(&remote->foreign_vcs, key, value);
 432         }
 433         return 0;
 434 }
 435
 436 static void alias_all_urls(void)
 437 {
 438         int i, j;
 439         for (i = 0; i < remotes_nr; i++) {
 440                 int add_pushurl_aliases;
 441                 if (!remotes[i])
 442                         continue;
 443                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 444                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 445                 }
 446                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 447                 for (j = 0; j < remotes[i]->url_nr; j++) {
 448                         if (add_pushurl_aliases)
 449                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 450                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 451                 }
 452         }
 453 }
 454
 455 static void read_config(void)
 456 {
 457         static int loaded;
 458         unsigned char sha1[20];
 459         const char *head_ref;
 460         int flag;
 461
 462         if (loaded)
 463                 return;
 464         loaded = 1;
 465
 466         current_branch = NULL;
 467         head_ref = resolve_ref_unsafe("HEAD", 0, sha1, &flag);
 468         if (head_ref && (flag & REF_ISSYMREF) &&
 469             skip_prefix(head_ref, "refs/heads/", &head_ref)) {
 470                 current_branch = make_branch(head_ref, 0);
 471         }
 472         git_config(handle_config, NULL);
 473         alias_all_urls();
 474 }
 475
 476 /*
 477  * This function frees a refspec array.
 478  * Warning: code paths should be checked to ensure that the src
 479  *          and dst pointers are always freeable pointers as well
 480  *          as the refspec pointer itself.
 481  */
 482 static void free_refspecs(struct refspec *refspec, int nr_refspec)
 483 {
 484         int i;
 485
 486         if (!refspec)
 487                 return;
 488
 489         for (i = 0; i < nr_refspec; i++) {
 490                 free(refspec[i].src);
 491                 free(refspec[i].dst);
 492         }
 493         free(refspec);
 494 }
 495
 496 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 497 {
 498         int i;
 499         struct refspec *rs = xcalloc(nr_refspec, sizeof(*rs));
 500
 501         for (i = 0; i < nr_refspec; i++) {
 502                 size_t llen;
 503                 int is_glob;
 504                 const char *lhs, *rhs;
 505                 int flags;
 506
 507                 is_glob = 0;
 508
 509                 lhs = refspec[i];
 510                 if (*lhs == '+') {
 511                         rs[i].force = 1;
 512                         lhs++;
 513                 }
 514
 515                 rhs = strrchr(lhs, ':');
 516
 517                 /*
 518                  * Before going on, special case ":" (or "+:") as a refspec
 519                  * for pushing matching refs.
 520                  */
 521                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
 522                         rs[i].matching = 1;
 523                         continue;
 524                 }
 525
 526                 if (rhs) {
 527                         size_t rlen = strlen(++rhs);
 528                         is_glob = (1 <= rlen && strchr(rhs, '*'));
 529                         rs[i].dst = xstrndup(rhs, rlen);
 530                 }
 531
 532                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 533                 if (1 <= llen && memchr(lhs, '*', llen)) {
 534                         if ((rhs && !is_glob) || (!rhs && fetch))
 535                                 goto invalid;
 536                         is_glob = 1;
 537                 } else if (rhs && is_glob) {
 538                         goto invalid;
 539                 }
 540
 541                 rs[i].pattern = is_glob;
 542                 rs[i].src = xstrndup(lhs, llen);
 543                 flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
 544
 545                 if (fetch) {
 546                         unsigned char unused[40];
 547
 548                         /* LHS */
 549                         if (!*rs[i].src)
 550                                 ; /* empty is ok; it means "HEAD" */
 551                         else if (llen == 40 && !get_sha1_hex(rs[i].src, unused))
 552                                 rs[i].exact_sha1 = 1; /* ok */
 553                         else if (!check_refname_format(rs[i].src, flags))
 554                                 ; /* valid looking ref is ok */
 555                         else
 556                                 goto invalid;
 557                         /* RHS */
 558                         if (!rs[i].dst)
 559                                 ; /* missing is ok; it is the same as empty */
 560                         else if (!*rs[i].dst)
 561                                 ; /* empty is ok; it means "do not store" */
 562                         else if (!check_refname_format(rs[i].dst, flags))
 563                                 ; /* valid looking ref is ok */
 564                         else
 565                                 goto invalid;
 566                 } else {
 567                         /*
 568                          * LHS
 569                          * - empty is allowed; it means delete.
 570                          * - when wildcarded, it must be a valid looking ref.
 571                          * - otherwise, it must be an extended SHA-1, but
 572                          *   there is no existing way to validate this.
 573                          */
 574                         if (!*rs[i].src)
 575                                 ; /* empty is ok */
 576                         else if (is_glob) {
 577                                 if (check_refname_format(rs[i].src, flags))
 578                                         goto invalid;
 579                         }
 580                         else
 581                                 ; /* anything goes, for now */
 582                         /*
 583                          * RHS
 584                          * - missing is allowed, but LHS then must be a
 585                          *   valid looking ref.
 586                          * - empty is not allowed.
 587                          * - otherwise it must be a valid looking ref.
 588                          */
 589                         if (!rs[i].dst) {
 590                                 if (check_refname_format(rs[i].src, flags))
 591                                         goto invalid;
 592                         } else if (!*rs[i].dst) {
 593                                 goto invalid;
 594                         } else {
 595                                 if (check_refname_format(rs[i].dst, flags))
 596                                         goto invalid;
 597                         }
 598                 }
 599         }
 600         return rs;
 601
 602  invalid:
 603         if (verify) {
 604                 /*
 605                  * nr_refspec must be greater than zero and i must be valid
 606                  * since it is only possible to reach this point from within
 607                  * the for loop above.
 608                  */
 609                 free_refspecs(rs, i+1);
 610                 return NULL;
 611         }
 612         die("Invalid refspec '%s'", refspec[i]);
 613 }
 614
 615 int valid_fetch_refspec(const char *fetch_refspec_str)
 616 {
 617         struct refspec *refspec;
 618
 619         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
 620         free_refspecs(refspec, 1);
 621         return !!refspec;
 622 }
 623
 624 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 625 {
 626         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 627 }
 628
 629 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 630 {
 631         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 632 }
 633
 634 void free_refspec(int nr_refspec, struct refspec *refspec)
 635 {
 636         int i;
 637         for (i = 0; i < nr_refspec; i++) {
 638                 free(refspec[i].src);
 639                 free(refspec[i].dst);
 640         }
 641         free(refspec);
 642 }
 643
 644 static int valid_remote_nick(const char *name)
 645 {
 646         if (!name[0] || is_dot_or_dotdot(name))
 647                 return 0;
 648         return !strchr(name, '/'); /* no slash */
 649 }
 650
 651 const char *remote_for_branch(struct branch *branch, int *explicit)
 652 {
 653         if (branch && branch->remote_name) {
 654                 if (explicit)
 655                         *explicit = 1;
 656                 return branch->remote_name;
 657         }
 658         if (explicit)
 659                 *explicit = 0;
 660         return "origin";
 661 }
 662
 663 const char *pushremote_for_branch(struct branch *branch, int *explicit)
 664 {
 665         if (branch && branch->pushremote_name) {
 666                 if (explicit)
 667                         *explicit = 1;
 668                 return branch->pushremote_name;
 669         }
 670         if (pushremote_name) {
 671                 if (explicit)
 672                         *explicit = 1;
 673                 return pushremote_name;
 674         }
 675         return remote_for_branch(branch, explicit);
 676 }
 677
 678 static struct remote *remote_get_1(const char *name,
 679                                    const char *(*get_default)(struct branch *, int *))
 680 {
 681         struct remote *ret;
 682         int name_given = 0;
 683
 684         read_config();
 685
 686         if (name)
 687                 name_given = 1;
 688         else
 689                 name = get_default(current_branch, &name_given);
 690
 691         ret = make_remote(name, 0);
 692         if (valid_remote_nick(name)) {
 693                 if (!valid_remote(ret))
 694                         read_remotes_file(ret);
 695                 if (!valid_remote(ret))
 696                         read_branches_file(ret);
 697         }
 698         if (name_given && !valid_remote(ret))
 699                 add_url_alias(ret, name);
 700         if (!valid_remote(ret))
 701                 return NULL;
 702         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 703         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 704         return ret;
 705 }
 706
 707 struct remote *remote_get(const char *name)
 708 {
 709         return remote_get_1(name, remote_for_branch);
 710 }
 711
 712 struct remote *pushremote_get(const char *name)
 713 {
 714         return remote_get_1(name, pushremote_for_branch);
 715 }
 716
 717 int remote_is_configured(const char *name)
 718 {
 719         struct remotes_hash_key lookup;
 720         struct hashmap_entry lookup_entry;
 721         read_config();
 722
 723         init_remotes_hash();
 724         lookup.str = name;
 725         lookup.len = strlen(name);
 726         hashmap_entry_init(&lookup_entry, memhash(name, lookup.len));
 727
 728         return hashmap_get(&remotes_hash, &lookup_entry, &lookup) != NULL;
 729 }
 730
 731 int for_each_remote(each_remote_fn fn, void *priv)
 732 {
 733         int i, result = 0;
 734         read_config();
 735         for (i = 0; i < remotes_nr && !result; i++) {
 736                 struct remote *r = remotes[i];
 737                 if (!r)
 738                         continue;
 739                 if (!r->fetch)
 740                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 741                                                        r->fetch_refspec);
 742                 if (!r->push)
 743                         r->push = parse_push_refspec(r->push_refspec_nr,
 744                                                      r->push_refspec);
 745                 result = fn(r, priv);
 746         }
 747         return result;
 748 }
 749
 750 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
 751 {
 752         if (strcmp(ref1->name, ref2->name)) {
 753                 if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 754                     ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
 755                         die(_("Cannot fetch both %s and %s to %s"),
 756                             ref1->name, ref2->name, ref2->peer_ref->name);
 757                 } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 758                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 759                         warning(_("%s usually tracks %s, not %s"),
 760                                 ref2->peer_ref->name, ref2->name, ref1->name);
 761                 } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
 762                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 763                         die(_("%s tracks both %s and %s"),
 764                             ref2->peer_ref->name, ref1->name, ref2->name);
 765                 } else {
 766                         /*
 767                          * This last possibility doesn't occur because
 768                          * FETCH_HEAD_IGNORE entries always appear at
 769                          * the end of the list.
 770                          */
 771                         die(_("Internal error"));
 772                 }
 773         }
 774         free(ref2->peer_ref);
 775         free(ref2);
 776 }
 777
 778 struct ref *ref_remove_duplicates(struct ref *ref_map)
 779 {
 780         struct string_list refs = STRING_LIST_INIT_NODUP;
 781         struct ref *retval = NULL;
 782         struct ref **p = &retval;
 783
 784         while (ref_map) {
 785                 struct ref *ref = ref_map;
 786
 787                 ref_map = ref_map->next;
 788                 ref->next = NULL;
 789
 790                 if (!ref->peer_ref) {
 791                         *p = ref;
 792                         p = &ref->next;
 793                 } else {
 794                         struct string_list_item *item =
 795                                 string_list_insert(&refs, ref->peer_ref->name);
 796
 797                         if (item->util) {
 798                                 /* Entry already existed */
 799                                 handle_duplicate((struct ref *)item->util, ref);
 800                         } else {
 801                                 *p = ref;
 802                                 p = &ref->next;
 803                                 item->util = ref;
 804                         }
 805                 }
 806         }
 807
 808         string_list_clear(&refs, 0);
 809         return retval;
 810 }
 811
 812 int remote_has_url(struct remote *remote, const char *url)
 813 {
 814         int i;
 815         for (i = 0; i < remote->url_nr; i++) {
 816                 if (!strcmp(remote->url[i], url))
 817                         return 1;
 818         }
 819         return 0;
 820 }
 821
 822 static int match_name_with_pattern(const char *key, const char *name,
 823                                    const char *value, char **result)
 824 {
 825         const char *kstar = strchr(key, '*');
 826         size_t klen;
 827         size_t ksuffixlen;
 828         size_t namelen;
 829         int ret;
 830         if (!kstar)
 831                 die("Key '%s' of pattern had no '*'", key);
 832         klen = kstar - key;
 833         ksuffixlen = strlen(kstar + 1);
 834         namelen = strlen(name);
 835         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 836                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 837         if (ret && value) {
 838                 struct strbuf sb = STRBUF_INIT;
 839                 const char *vstar = strchr(value, '*');
 840                 if (!vstar)
 841                         die("Value '%s' of pattern has no '*'", value);
 842                 strbuf_add(&sb, value, vstar - value);
 843                 strbuf_add(&sb, name + klen, namelen - klen - ksuffixlen);
 844                 strbuf_addstr(&sb, vstar + 1);
 845                 *result = strbuf_detach(&sb, NULL);
 846         }
 847         return ret;
 848 }
 849
 850 static void query_refspecs_multiple(struct refspec *refs, int ref_count, struct refspec *query, struct string_list *results)
 851 {
 852         int i;
 853         int find_src = !query->src;
 854
 855         if (find_src && !query->dst)
 856                 error("query_refspecs_multiple: need either src or dst");
 857
 858         for (i = 0; i < ref_count; i++) {
 859                 struct refspec *refspec = &refs[i];
 860                 const char *key = find_src ? refspec->dst : refspec->src;
 861                 const char *value = find_src ? refspec->src : refspec->dst;
 862                 const char *needle = find_src ? query->dst : query->src;
 863                 char **result = find_src ? &query->src : &query->dst;
 864
 865                 if (!refspec->dst)
 866                         continue;
 867                 if (refspec->pattern) {
 868                         if (match_name_with_pattern(key, needle, value, result))
 869                                 string_list_append_nodup(results, *result);
 870                 } else if (!strcmp(needle, key)) {
 871                         string_list_append(results, value);
 872                 }
 873         }
 874 }
 875
 876 int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
 877 {
 878         int i;
 879         int find_src = !query->src;
 880         const char *needle = find_src ? query->dst : query->src;
 881         char **result = find_src ? &query->src : &query->dst;
 882
 883         if (find_src && !query->dst)
 884                 return error("query_refspecs: need either src or dst");
 885
 886         for (i = 0; i < ref_count; i++) {
 887                 struct refspec *refspec = &refs[i];
 888                 const char *key = find_src ? refspec->dst : refspec->src;
 889                 const char *value = find_src ? refspec->src : refspec->dst;
 890
 891                 if (!refspec->dst)
 892                         continue;
 893                 if (refspec->pattern) {
 894                         if (match_name_with_pattern(key, needle, value, result)) {
 895                                 query->force = refspec->force;
 896                                 return 0;
 897                         }
 898                 } else if (!strcmp(needle, key)) {
 899                         *result = xstrdup(value);
 900                         query->force = refspec->force;
 901                         return 0;
 902                 }
 903         }
 904         return -1;
 905 }
 906
 907 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 908                      const char *name)
 909 {
 910         struct refspec query;
 911
 912         memset(&query, 0, sizeof(struct refspec));
 913         query.src = (char *)name;
 914
 915         if (query_refspecs(refspecs, nr_refspec, &query))
 916                 return NULL;
 917
 918         return query.dst;
 919 }
 920
 921 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 922 {
 923         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
 924 }
 925
 926 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 927                 const char *name)
 928 {
 929         size_t len = strlen(name);
 930         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 931         memcpy(ref->name, prefix, prefixlen);
 932         memcpy(ref->name + prefixlen, name, len);
 933         return ref;
 934 }
 935
 936 struct ref *alloc_ref(const char *name)
 937 {
 938         return alloc_ref_with_prefix("", 0, name);
 939 }
 940
 941 struct ref *copy_ref(const struct ref *ref)
 942 {
 943         struct ref *cpy;
 944         size_t len;
 945         if (!ref)
 946                 return NULL;
 947         len = strlen(ref->name);
 948         cpy = xmalloc(sizeof(struct ref) + len + 1);
 949         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 950         cpy->next = NULL;
 951         cpy->symref = xstrdup_or_null(ref->symref);
 952         cpy->remote_status = xstrdup_or_null(ref->remote_status);
 953         cpy->peer_ref = copy_ref(ref->peer_ref);
 954         return cpy;
 955 }
 956
 957 struct ref *copy_ref_list(const struct ref *ref)
 958 {
 959         struct ref *ret = NULL;
 960         struct ref **tail = &ret;
 961         while (ref) {
 962                 *tail = copy_ref(ref);
 963                 ref = ref->next;
 964                 tail = &((*tail)->next);
 965         }
 966         return ret;
 967 }
 968
 969 static void free_ref(struct ref *ref)
 970 {
 971         if (!ref)
 972                 return;
 973         free_ref(ref->peer_ref);
 974         free(ref->remote_status);
 975         free(ref->symref);
 976         free(ref);
 977 }
 978
 979 void free_refs(struct ref *ref)
 980 {
 981         struct ref *next;
 982         while (ref) {
 983                 next = ref->next;
 984                 free_ref(ref);
 985                 ref = next;
 986         }
 987 }
 988
 989 int ref_compare_name(const void *va, const void *vb)
 990 {
 991         const struct ref *a = va, *b = vb;
 992         return strcmp(a->name, b->name);
 993 }
 994
 995 static void *ref_list_get_next(const void *a)
 996 {
 997         return ((const struct ref *)a)->next;
 998 }
 999
1000 static void ref_list_set_next(void *a, void *next)
1001 {
1002         ((struct ref *)a)->next = next;
1003 }
1004
1005 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
1006 {
1007         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
1008 }
1009
1010 int count_refspec_match(const char *pattern,
1011                         struct ref *refs,
1012                         struct ref **matched_ref)
1013 {
1014         int patlen = strlen(pattern);
1015         struct ref *matched_weak = NULL;
1016         struct ref *matched = NULL;
1017         int weak_match = 0;
1018         int match = 0;
1019
1020         for (weak_match = match = 0; refs; refs = refs->next) {
1021                 char *name = refs->name;
1022                 int namelen = strlen(name);
1023
1024                 if (!refname_match(pattern, name))
1025                         continue;
1026
1027                 /* A match is "weak" if it is with refs outside
1028                  * heads or tags, and did not specify the pattern
1029                  * in full (e.g. "refs/remotes/origin/master") or at
1030                  * least from the toplevel (e.g. "remotes/origin/master");
1031                  * otherwise "git push $URL master" would result in
1032                  * ambiguity between remotes/origin/master and heads/master
1033                  * at the remote site.
1034                  */
1035                 if (namelen != patlen &&
1036                     patlen != namelen - 5 &&
1037                     !starts_with(name, "refs/heads/") &&
1038                     !starts_with(name, "refs/tags/")) {
1039                         /* We want to catch the case where only weak
1040                          * matches are found and there are multiple
1041                          * matches, and where more than one strong
1042                          * matches are found, as ambiguous.  One
1043                          * strong match with zero or more weak matches
1044                          * are acceptable as a unique match.
1045                          */
1046                         matched_weak = refs;
1047                         weak_match++;
1048                 }
1049                 else {
1050                         matched = refs;
1051                         match++;
1052                 }
1053         }
1054         if (!matched) {
1055                 if (matched_ref)
1056                         *matched_ref = matched_weak;
1057                 return weak_match;
1058         }
1059         else {
1060                 if (matched_ref)
1061                         *matched_ref = matched;
1062                 return match;
1063         }
1064 }
1065
1066 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1067 {
1068         **tail = ref;
1069         while (ref->next)
1070                 ref = ref->next;
1071         *tail = &ref->next;
1072 }
1073
1074 static struct ref *alloc_delete_ref(void)
1075 {
1076         struct ref *ref = alloc_ref("(delete)");
1077         hashclr(ref->new_sha1);
1078         return ref;
1079 }
1080
1081 static int try_explicit_object_name(const char *name,
1082                                     struct ref **match)
1083 {
1084         unsigned char sha1[20];
1085
1086         if (!*name) {
1087                 if (match)
1088                         *match = alloc_delete_ref();
1089                 return 0;
1090         }
1091
1092         if (get_sha1(name, sha1))
1093                 return -1;
1094
1095         if (match) {
1096                 *match = alloc_ref(name);
1097                 hashcpy((*match)->new_sha1, sha1);
1098         }
1099         return 0;
1100 }
1101
1102 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1103 {
1104         struct ref *ret = alloc_ref(name);
1105         tail_link_ref(ret, tail);
1106         return ret;
1107 }
1108
1109 static char *guess_ref(const char *name, struct ref *peer)
1110 {
1111         struct strbuf buf = STRBUF_INIT;
1112         unsigned char sha1[20];
1113
1114         const char *r = resolve_ref_unsafe(peer->name, RESOLVE_REF_READING,
1115                                            sha1, NULL);
1116         if (!r)
1117                 return NULL;
1118
1119         if (starts_with(r, "refs/heads/"))
1120                 strbuf_addstr(&buf, "refs/heads/");
1121         else if (starts_with(r, "refs/tags/"))
1122                 strbuf_addstr(&buf, "refs/tags/");
1123         else
1124                 return NULL;
1125
1126         strbuf_addstr(&buf, name);
1127         return strbuf_detach(&buf, NULL);
1128 }
1129
1130 static int match_explicit_lhs(struct ref *src,
1131                               struct refspec *rs,
1132                               struct ref **match,
1133                               int *allocated_match)
1134 {
1135         switch (count_refspec_match(rs->src, src, match)) {
1136         case 1:
1137                 if (allocated_match)
1138                         *allocated_match = 0;
1139                 return 0;
1140         case 0:
1141                 /* The source could be in the get_sha1() format
1142                  * not a reference name.  :refs/other is a
1143                  * way to delete 'other' ref at the remote end.
1144                  */
1145                 if (try_explicit_object_name(rs->src, match) < 0)
1146                         return error("src refspec %s does not match any.", rs->src);
1147                 if (allocated_match)
1148                         *allocated_match = 1;
1149                 return 0;
1150         default:
1151                 return error("src refspec %s matches more than one.", rs->src);
1152         }
1153 }
1154
1155 static int match_explicit(struct ref *src, struct ref *dst,
1156                           struct ref ***dst_tail,
1157                           struct refspec *rs)
1158 {
1159         struct ref *matched_src, *matched_dst;
1160         int allocated_src;
1161
1162         const char *dst_value = rs->dst;
1163         char *dst_guess;
1164
1165         if (rs->pattern || rs->matching)
1166                 return 0;
1167
1168         matched_src = matched_dst = NULL;
1169         if (match_explicit_lhs(src, rs, &matched_src, &allocated_src) < 0)
1170                 return -1;
1171
1172         if (!dst_value) {
1173                 unsigned char sha1[20];
1174                 int flag;
1175
1176                 dst_value = resolve_ref_unsafe(matched_src->name,
1177                                                RESOLVE_REF_READING,
1178                                                sha1, &flag);
1179                 if (!dst_value ||
1180                     ((flag & REF_ISSYMREF) &&
1181                      !starts_with(dst_value, "refs/heads/")))
1182                         die("%s cannot be resolved to branch.",
1183                             matched_src->name);
1184         }
1185
1186         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1187         case 1:
1188                 break;
1189         case 0:
1190                 if (starts_with(dst_value, "refs/"))
1191                         matched_dst = make_linked_ref(dst_value, dst_tail);
1192                 else if (is_null_sha1(matched_src->new_sha1))
1193                         error("unable to delete '%s': remote ref does not exist",
1194                               dst_value);
1195                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1196                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1197                 else
1198                         error("unable to push to unqualified destination: %s\n"
1199                               "The destination refspec neither matches an "
1200                               "existing ref on the remote nor\n"
1201                               "begins with refs/, and we are unable to "
1202                               "guess a prefix based on the source ref.",
1203                               dst_value);
1204                 break;
1205         default:
1206                 matched_dst = NULL;
1207                 error("dst refspec %s matches more than one.",
1208                       dst_value);
1209                 break;
1210         }
1211         if (!matched_dst)
1212                 return -1;
1213         if (matched_dst->peer_ref)
1214                 return error("dst ref %s receives from more than one src.",
1215                       matched_dst->name);
1216         else {
1217                 matched_dst->peer_ref = allocated_src ?
1218                                         matched_src :
1219                                         copy_ref(matched_src);
1220                 matched_dst->force = rs->force;
1221         }
1222         return 0;
1223 }
1224
1225 static int match_explicit_refs(struct ref *src, struct ref *dst,
1226                                struct ref ***dst_tail, struct refspec *rs,
1227                                int rs_nr)
1228 {
1229         int i, errs;
1230         for (i = errs = 0; i < rs_nr; i++)
1231                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1232         return errs;
1233 }
1234
1235 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1236                 int send_mirror, int direction, const struct refspec **ret_pat)
1237 {
1238         const struct refspec *pat;
1239         char *name;
1240         int i;
1241         int matching_refs = -1;
1242         for (i = 0; i < rs_nr; i++) {
1243                 if (rs[i].matching &&
1244                     (matching_refs == -1 || rs[i].force)) {
1245                         matching_refs = i;
1246                         continue;
1247                 }
1248
1249                 if (rs[i].pattern) {
1250                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1251                         int match;
1252                         if (direction == FROM_SRC)
1253                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1254                         else
1255                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1256                         if (match) {
1257                                 matching_refs = i;
1258                                 break;
1259                         }
1260                 }
1261         }
1262         if (matching_refs == -1)
1263                 return NULL;
1264
1265         pat = rs + matching_refs;
1266         if (pat->matching) {
1267                 /*
1268                  * "matching refs"; traditionally we pushed everything
1269                  * including refs outside refs/heads/ hierarchy, but
1270                  * that does not make much sense these days.
1271                  */
1272                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1273                         return NULL;
1274                 name = xstrdup(ref->name);
1275         }
1276         if (ret_pat)
1277                 *ret_pat = pat;
1278         return name;
1279 }
1280
1281 static struct ref **tail_ref(struct ref **head)
1282 {
1283         struct ref **tail = head;
1284         while (*tail)
1285                 tail = &((*tail)->next);
1286         return tail;
1287 }
1288
1289 struct tips {
1290         struct commit **tip;
1291         int nr, alloc;
1292 };
1293
1294 static void add_to_tips(struct tips *tips, const unsigned char *sha1)
1295 {
1296         struct commit *commit;
1297
1298         if (is_null_sha1(sha1))
1299                 return;
1300         commit = lookup_commit_reference_gently(sha1, 1);
1301         if (!commit || (commit->object.flags & TMP_MARK))
1302                 return;
1303         commit->object.flags |= TMP_MARK;
1304         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1305         tips->tip[tips->nr++] = commit;
1306 }
1307
1308 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1309 {
1310         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1311         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1312         struct string_list_item *item;
1313         struct ref *ref;
1314         struct tips sent_tips;
1315
1316         /*
1317          * Collect everything we know they would have at the end of
1318          * this push, and collect all tags they have.
1319          */
1320         memset(&sent_tips, 0, sizeof(sent_tips));
1321         for (ref = *dst; ref; ref = ref->next) {
1322                 if (ref->peer_ref &&
1323                     !is_null_sha1(ref->peer_ref->new_sha1))
1324                         add_to_tips(&sent_tips, ref->peer_ref->new_sha1);
1325                 else
1326                         add_to_tips(&sent_tips, ref->old_sha1);
1327                 if (starts_with(ref->name, "refs/tags/"))
1328                         string_list_append(&dst_tag, ref->name);
1329         }
1330         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1331
1332         string_list_sort(&dst_tag);
1333
1334         /* Collect tags they do not have. */
1335         for (ref = src; ref; ref = ref->next) {
1336                 if (!starts_with(ref->name, "refs/tags/"))
1337                         continue; /* not a tag */
1338                 if (string_list_has_string(&dst_tag, ref->name))
1339                         continue; /* they already have it */
1340                 if (sha1_object_info(ref->new_sha1, NULL) != OBJ_TAG)
1341                         continue; /* be conservative */
1342                 item = string_list_append(&src_tag, ref->name);
1343                 item->util = ref;
1344         }
1345         string_list_clear(&dst_tag, 0);
1346
1347         /*
1348          * At this point, src_tag lists tags that are missing from
1349          * dst, and sent_tips lists the tips we are pushing or those
1350          * that we know they already have. An element in the src_tag
1351          * that is an ancestor of any of the sent_tips needs to be
1352          * sent to the other side.
1353          */
1354         if (sent_tips.nr) {
1355                 for_each_string_list_item(item, &src_tag) {
1356                         struct ref *ref = item->util;
1357                         struct ref *dst_ref;
1358                         struct commit *commit;
1359
1360                         if (is_null_sha1(ref->new_sha1))
1361                                 continue;
1362                         commit = lookup_commit_reference_gently(ref->new_sha1, 1);
1363                         if (!commit)
1364                                 /* not pushing a commit, which is not an error */
1365                                 continue;
1366
1367                         /*
1368                          * Is this tag, which they do not have, reachable from
1369                          * any of the commits we are sending?
1370                          */
1371                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1372                                 continue;
1373
1374                         /* Add it in */
1375                         dst_ref = make_linked_ref(ref->name, dst_tail);
1376                         hashcpy(dst_ref->new_sha1, ref->new_sha1);
1377                         dst_ref->peer_ref = copy_ref(ref);
1378                 }
1379         }
1380         string_list_clear(&src_tag, 0);
1381         free(sent_tips.tip);
1382 }
1383
1384 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1385 {
1386         for ( ; list; list = list->next)
1387                 if (!strcmp(list->name, name))
1388                         return (struct ref *)list;
1389         return NULL;
1390 }
1391
1392 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1393 {
1394         for ( ; ref; ref = ref->next)
1395                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1396
1397         string_list_sort(ref_index);
1398 }
1399
1400 /*
1401  * Given only the set of local refs, sanity-check the set of push
1402  * refspecs. We can't catch all errors that match_push_refs would,
1403  * but we can catch some errors early before even talking to the
1404  * remote side.
1405  */
1406 int check_push_refs(struct ref *src, int nr_refspec, const char **refspec_names)
1407 {
1408         struct refspec *refspec = parse_push_refspec(nr_refspec, refspec_names);
1409         int ret = 0;
1410         int i;
1411
1412         for (i = 0; i < nr_refspec; i++) {
1413                 struct refspec *rs = refspec + i;
1414
1415                 if (rs->pattern || rs->matching)
1416                         continue;
1417
1418                 ret |= match_explicit_lhs(src, rs, NULL, NULL);
1419         }
1420
1421         free_refspec(nr_refspec, refspec);
1422         return ret;
1423 }
1424
1425 /*
1426  * Given the set of refs the local repository has, the set of refs the
1427  * remote repository has, and the refspec used for push, determine
1428  * what remote refs we will update and with what value by setting
1429  * peer_ref (which object is being pushed) and force (if the push is
1430  * forced) in elements of "dst". The function may add new elements to
1431  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1432  */
1433 int match_push_refs(struct ref *src, struct ref **dst,
1434                     int nr_refspec, const char **refspec, int flags)
1435 {
1436         struct refspec *rs;
1437         int send_all = flags & MATCH_REFS_ALL;
1438         int send_mirror = flags & MATCH_REFS_MIRROR;
1439         int send_prune = flags & MATCH_REFS_PRUNE;
1440         int errs;
1441         static const char *default_refspec[] = { ":", NULL };
1442         struct ref *ref, **dst_tail = tail_ref(dst);
1443         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1444
1445         if (!nr_refspec) {
1446                 nr_refspec = 1;
1447                 refspec = default_refspec;
1448         }
1449         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1450         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1451
1452         /* pick the remainder */
1453         for (ref = src; ref; ref = ref->next) {
1454                 struct string_list_item *dst_item;
1455                 struct ref *dst_peer;
1456                 const struct refspec *pat = NULL;
1457                 char *dst_name;
1458
1459                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1460                 if (!dst_name)
1461                         continue;
1462
1463                 if (!dst_ref_index.nr)
1464                         prepare_ref_index(&dst_ref_index, *dst);
1465
1466                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1467                 dst_peer = dst_item ? dst_item->util : NULL;
1468                 if (dst_peer) {
1469                         if (dst_peer->peer_ref)
1470                                 /* We're already sending something to this ref. */
1471                                 goto free_name;
1472                 } else {
1473                         if (pat->matching && !(send_all || send_mirror))
1474                                 /*
1475                                  * Remote doesn't have it, and we have no
1476                                  * explicit pattern, and we don't have
1477                                  * --all or --mirror.
1478                                  */
1479                                 goto free_name;
1480
1481                         /* Create a new one and link it */
1482                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1483                         hashcpy(dst_peer->new_sha1, ref->new_sha1);
1484                         string_list_insert(&dst_ref_index,
1485                                 dst_peer->name)->util = dst_peer;
1486                 }
1487                 dst_peer->peer_ref = copy_ref(ref);
1488                 dst_peer->force = pat->force;
1489         free_name:
1490                 free(dst_name);
1491         }
1492
1493         string_list_clear(&dst_ref_index, 0);
1494
1495         if (flags & MATCH_REFS_FOLLOW_TAGS)
1496                 add_missing_tags(src, dst, &dst_tail);
1497
1498         if (send_prune) {
1499                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1500                 /* check for missing refs on the remote */
1501                 for (ref = *dst; ref; ref = ref->next) {
1502                         char *src_name;
1503
1504                         if (ref->peer_ref)
1505                                 /* We're already sending something to this ref. */
1506                                 continue;
1507
1508                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1509                         if (src_name) {
1510                                 if (!src_ref_index.nr)
1511                                         prepare_ref_index(&src_ref_index, src);
1512                                 if (!string_list_has_string(&src_ref_index,
1513                                             src_name))
1514                                         ref->peer_ref = alloc_delete_ref();
1515                                 free(src_name);
1516                         }
1517                 }
1518                 string_list_clear(&src_ref_index, 0);
1519         }
1520         if (errs)
1521                 return -1;
1522         return 0;
1523 }
1524
1525 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1526                              int force_update)
1527 {
1528         struct ref *ref;
1529
1530         for (ref = remote_refs; ref; ref = ref->next) {
1531                 int force_ref_update = ref->force || force_update;
1532                 int reject_reason = 0;
1533
1534                 if (ref->peer_ref)
1535                         hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
1536                 else if (!send_mirror)
1537                         continue;
1538
1539                 ref->deletion = is_null_sha1(ref->new_sha1);
1540                 if (!ref->deletion &&
1541                         !hashcmp(ref->old_sha1, ref->new_sha1)) {
1542                         ref->status = REF_STATUS_UPTODATE;
1543                         continue;
1544                 }
1545
1546                 /*
1547                  * Bypass the usual "must fast-forward" check but
1548                  * replace it with a weaker "the old value must be
1549                  * this value we observed".  If the remote ref has
1550                  * moved and is now different from what we expect,
1551                  * reject any push.
1552                  *
1553                  * It also is an error if the user told us to check
1554                  * with the remote-tracking branch to find the value
1555                  * to expect, but we did not have such a tracking
1556                  * branch.
1557                  */
1558                 if (ref->expect_old_sha1) {
1559                         if (ref->expect_old_no_trackback ||
1560                             hashcmp(ref->old_sha1, ref->old_sha1_expect))
1561                                 reject_reason = REF_STATUS_REJECT_STALE;
1562                 }
1563
1564                 /*
1565                  * The usual "must fast-forward" rules.
1566                  *
1567                  * Decide whether an individual refspec A:B can be
1568                  * pushed.  The push will succeed if any of the
1569                  * following are true:
1570                  *
1571                  * (1) the remote reference B does not exist
1572                  *
1573                  * (2) the remote reference B is being removed (i.e.,
1574                  *     pushing :B where no source is specified)
1575                  *
1576                  * (3) the destination is not under refs/tags/, and
1577                  *     if the old and new value is a commit, the new
1578                  *     is a descendant of the old.
1579                  *
1580                  * (4) it is forced using the +A:B notation, or by
1581                  *     passing the --force argument
1582                  */
1583
1584                 else if (!ref->deletion && !is_null_sha1(ref->old_sha1)) {
1585                         if (starts_with(ref->name, "refs/tags/"))
1586                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1587                         else if (!has_sha1_file(ref->old_sha1))
1588                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1589                         else if (!lookup_commit_reference_gently(ref->old_sha1, 1) ||
1590                                  !lookup_commit_reference_gently(ref->new_sha1, 1))
1591                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1592                         else if (!ref_newer(ref->new_sha1, ref->old_sha1))
1593                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1594                 }
1595
1596                 /*
1597                  * "--force" will defeat any rejection implemented
1598                  * by the rules above.
1599                  */
1600                 if (!force_ref_update)
1601                         ref->status = reject_reason;
1602                 else if (reject_reason)
1603                         ref->forced_update = 1;
1604         }
1605 }
1606
1607 static void set_merge(struct branch *ret)
1608 {
1609         struct remote *remote;
1610         char *ref;
1611         unsigned char sha1[20];
1612         int i;
1613
1614         if (!ret)
1615                 return; /* no branch */
1616         if (ret->merge)
1617                 return; /* already run */
1618         if (!ret->remote_name || !ret->merge_nr) {
1619                 /*
1620                  * no merge config; let's make sure we don't confuse callers
1621                  * with a non-zero merge_nr but a NULL merge
1622                  */
1623                 ret->merge_nr = 0;
1624                 return;
1625         }
1626
1627         remote = remote_get(ret->remote_name);
1628
1629         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1630         for (i = 0; i < ret->merge_nr; i++) {
1631                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1632                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1633                 if (!remote_find_tracking(remote, ret->merge[i]) ||
1634                     strcmp(ret->remote_name, "."))
1635                         continue;
1636                 if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
1637                              sha1, &ref) == 1)
1638                         ret->merge[i]->dst = ref;
1639                 else
1640                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1641         }
1642 }
1643
1644 struct branch *branch_get(const char *name)
1645 {
1646         struct branch *ret;
1647
1648         read_config();
1649         if (!name || !*name || !strcmp(name, "HEAD"))
1650                 ret = current_branch;
1651         else
1652                 ret = make_branch(name, 0);
1653         set_merge(ret);
1654         return ret;
1655 }
1656
1657 int branch_has_merge_config(struct branch *branch)
1658 {
1659         return branch && !!branch->merge;
1660 }
1661
1662 int branch_merge_matches(struct branch *branch,
1663                                  int i,
1664                                  const char *refname)
1665 {
1666         if (!branch || i < 0 || i >= branch->merge_nr)
1667                 return 0;
1668         return refname_match(branch->merge[i]->src, refname);
1669 }
1670
1671 __attribute((format (printf,2,3)))
1672 static const char *error_buf(struct strbuf *err, const char *fmt, ...)
1673 {
1674         if (err) {
1675                 va_list ap;
1676                 va_start(ap, fmt);
1677                 strbuf_vaddf(err, fmt, ap);
1678                 va_end(ap);
1679         }
1680         return NULL;
1681 }
1682
1683 const char *branch_get_upstream(struct branch *branch, struct strbuf *err)
1684 {
1685         if (!branch)
1686                 return error_buf(err, _("HEAD does not point to a branch"));
1687
1688         if (!branch->merge || !branch->merge[0]) {
1689                 /*
1690                  * no merge config; is it because the user didn't define any,
1691                  * or because it is not a real branch, and get_branch
1692                  * auto-vivified it?
1693                  */
1694                 if (!ref_exists(branch->refname))
1695                         return error_buf(err, _("no such branch: '%s'"),
1696                                          branch->name);
1697                 return error_buf(err,
1698                                  _("no upstream configured for branch '%s'"),
1699                                  branch->name);
1700         }
1701
1702         if (!branch->merge[0]->dst)
1703                 return error_buf(err,
1704                                  _("upstream branch '%s' not stored as a remote-tracking branch"),
1705                                  branch->merge[0]->src);
1706
1707         return branch->merge[0]->dst;
1708 }
1709
1710 static const char *tracking_for_push_dest(struct remote *remote,
1711                                           const char *refname,
1712                                           struct strbuf *err)
1713 {
1714         char *ret;
1715
1716         ret = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
1717         if (!ret)
1718                 return error_buf(err,
1719                                  _("push destination '%s' on remote '%s' has no local tracking branch"),
1720                                  refname, remote->name);
1721         return ret;
1722 }
1723
1724 static const char *branch_get_push_1(struct branch *branch, struct strbuf *err)
1725 {
1726         struct remote *remote;
1727
1728         if (!branch)
1729                 return error_buf(err, _("HEAD does not point to a branch"));
1730
1731         remote = remote_get(pushremote_for_branch(branch, NULL));
1732         if (!remote)
1733                 return error_buf(err,
1734                                  _("branch '%s' has no remote for pushing"),
1735                                  branch->name);
1736
1737         if (remote->push_refspec_nr) {
1738                 char *dst;
1739                 const char *ret;
1740
1741                 dst = apply_refspecs(remote->push, remote->push_refspec_nr,
1742                                      branch->refname);
1743                 if (!dst)
1744                         return error_buf(err,
1745                                          _("push refspecs for '%s' do not include '%s'"),
1746                                          remote->name, branch->name);
1747
1748                 ret = tracking_for_push_dest(remote, dst, err);
1749                 free(dst);
1750                 return ret;
1751         }
1752
1753         if (remote->mirror)
1754                 return tracking_for_push_dest(remote, branch->refname, err);
1755
1756         switch (push_default) {
1757         case PUSH_DEFAULT_NOTHING:
1758                 return error_buf(err, _("push has no destination (push.default is 'nothing')"));
1759
1760         case PUSH_DEFAULT_MATCHING:
1761         case PUSH_DEFAULT_CURRENT:
1762                 return tracking_for_push_dest(remote, branch->refname, err);
1763
1764         case PUSH_DEFAULT_UPSTREAM:
1765                 return branch_get_upstream(branch, err);
1766
1767         case PUSH_DEFAULT_UNSPECIFIED:
1768         case PUSH_DEFAULT_SIMPLE:
1769                 {
1770                         const char *up, *cur;
1771
1772                         up = branch_get_upstream(branch, err);
1773                         if (!up)
1774                                 return NULL;
1775                         cur = tracking_for_push_dest(remote, branch->refname, err);
1776                         if (!cur)
1777                                 return NULL;
1778                         if (strcmp(cur, up))
1779                                 return error_buf(err,
1780                                                  _("cannot resolve 'simple' push to a single destination"));
1781                         return cur;
1782                 }
1783         }
1784
1785         die("BUG: unhandled push situation");
1786 }
1787
1788 const char *branch_get_push(struct branch *branch, struct strbuf *err)
1789 {
1790         if (!branch->push_tracking_ref)
1791                 branch->push_tracking_ref = branch_get_push_1(branch, err);
1792         return branch->push_tracking_ref;
1793 }
1794
1795 static int ignore_symref_update(const char *refname)
1796 {
1797         unsigned char sha1[20];
1798         int flag;
1799
1800         if (!resolve_ref_unsafe(refname, 0, sha1, &flag))
1801                 return 0; /* non-existing refs are OK */
1802         return (flag & REF_ISSYMREF);
1803 }
1804
1805 /*
1806  * Create and return a list of (struct ref) consisting of copies of
1807  * each remote_ref that matches refspec.  refspec must be a pattern.
1808  * Fill in the copies' peer_ref to describe the local tracking refs to
1809  * which they map.  Omit any references that would map to an existing
1810  * local symbolic ref.
1811  */
1812 static struct ref *get_expanded_map(const struct ref *remote_refs,
1813                                     const struct refspec *refspec)
1814 {
1815         const struct ref *ref;
1816         struct ref *ret = NULL;
1817         struct ref **tail = &ret;
1818
1819         for (ref = remote_refs; ref; ref = ref->next) {
1820                 char *expn_name = NULL;
1821
1822                 if (strchr(ref->name, '^'))
1823                         continue; /* a dereference item */
1824                 if (match_name_with_pattern(refspec->src, ref->name,
1825                                             refspec->dst, &expn_name) &&
1826                     !ignore_symref_update(expn_name)) {
1827                         struct ref *cpy = copy_ref(ref);
1828
1829                         cpy->peer_ref = alloc_ref(expn_name);
1830                         if (refspec->force)
1831                                 cpy->peer_ref->force = 1;
1832                         *tail = cpy;
1833                         tail = &cpy->next;
1834                 }
1835                 free(expn_name);
1836         }
1837
1838         return ret;
1839 }
1840
1841 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1842 {
1843         const struct ref *ref;
1844         for (ref = refs; ref; ref = ref->next) {
1845                 if (refname_match(name, ref->name))
1846                         return ref;
1847         }
1848         return NULL;
1849 }
1850
1851 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1852 {
1853         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1854
1855         if (!ref)
1856                 return NULL;
1857
1858         return copy_ref(ref);
1859 }
1860
1861 static struct ref *get_local_ref(const char *name)
1862 {
1863         if (!name || name[0] == '\0')
1864                 return NULL;
1865
1866         if (starts_with(name, "refs/"))
1867                 return alloc_ref(name);
1868
1869         if (starts_with(name, "heads/") ||
1870             starts_with(name, "tags/") ||
1871             starts_with(name, "remotes/"))
1872                 return alloc_ref_with_prefix("refs/", 5, name);
1873
1874         return alloc_ref_with_prefix("refs/heads/", 11, name);
1875 }
1876
1877 int get_fetch_map(const struct ref *remote_refs,
1878                   const struct refspec *refspec,
1879                   struct ref ***tail,
1880                   int missing_ok)
1881 {
1882         struct ref *ref_map, **rmp;
1883
1884         if (refspec->pattern) {
1885                 ref_map = get_expanded_map(remote_refs, refspec);
1886         } else {
1887                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1888
1889                 if (refspec->exact_sha1) {
1890                         ref_map = alloc_ref(name);
1891                         get_sha1_hex(name, ref_map->old_sha1);
1892                 } else {
1893                         ref_map = get_remote_ref(remote_refs, name);
1894                 }
1895                 if (!missing_ok && !ref_map)
1896                         die("Couldn't find remote ref %s", name);
1897                 if (ref_map) {
1898                         ref_map->peer_ref = get_local_ref(refspec->dst);
1899                         if (ref_map->peer_ref && refspec->force)
1900                                 ref_map->peer_ref->force = 1;
1901                 }
1902         }
1903
1904         for (rmp = &ref_map; *rmp; ) {
1905                 if ((*rmp)->peer_ref) {
1906                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1907                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1908                                 struct ref *ignore = *rmp;
1909                                 error("* Ignoring funny ref '%s' locally",
1910                                       (*rmp)->peer_ref->name);
1911                                 *rmp = (*rmp)->next;
1912                                 free(ignore->peer_ref);
1913                                 free(ignore);
1914                                 continue;
1915                         }
1916                 }
1917                 rmp = &((*rmp)->next);
1918         }
1919
1920         if (ref_map)
1921                 tail_link_ref(ref_map, tail);
1922
1923         return 0;
1924 }
1925
1926 int resolve_remote_symref(struct ref *ref, struct ref *list)
1927 {
1928         if (!ref->symref)
1929                 return 0;
1930         for (; list; list = list->next)
1931                 if (!strcmp(ref->symref, list->name)) {
1932                         hashcpy(ref->old_sha1, list->old_sha1);
1933                         return 0;
1934                 }
1935         return 1;
1936 }
1937
1938 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1939 {
1940         while (list) {
1941                 struct commit_list *temp = list;
1942                 temp->item->object.flags &= ~mark;
1943                 list = temp->next;
1944                 free(temp);
1945         }
1946 }
1947
1948 int ref_newer(const unsigned char *new_sha1, const unsigned char *old_sha1)
1949 {
1950         struct object *o;
1951         struct commit *old, *new;
1952         struct commit_list *list, *used;
1953         int found = 0;
1954
1955         /*
1956          * Both new and old must be commit-ish and new is descendant of
1957          * old.  Otherwise we require --force.
1958          */
1959         o = deref_tag(parse_object(old_sha1), NULL, 0);
1960         if (!o || o->type != OBJ_COMMIT)
1961                 return 0;
1962         old = (struct commit *) o;
1963
1964         o = deref_tag(parse_object(new_sha1), NULL, 0);
1965         if (!o || o->type != OBJ_COMMIT)
1966                 return 0;
1967         new = (struct commit *) o;
1968
1969         if (parse_commit(new) < 0)
1970                 return 0;
1971
1972         used = list = NULL;
1973         commit_list_insert(new, &list);
1974         while (list) {
1975                 new = pop_most_recent_commit(&list, TMP_MARK);
1976                 commit_list_insert(new, &used);
1977                 if (new == old) {
1978                         found = 1;
1979                         break;
1980                 }
1981         }
1982         unmark_and_free(list, TMP_MARK);
1983         unmark_and_free(used, TMP_MARK);
1984         return found;
1985 }
1986
1987 /*
1988  * Compare a branch with its upstream, and save their differences (number
1989  * of commits) in *num_ours and *num_theirs. The name of the upstream branch
1990  * (or NULL if no upstream is defined) is returned via *upstream_name, if it
1991  * is not itself NULL.
1992  *
1993  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
1994  * upstream defined, or ref does not exist), 0 otherwise.
1995  */
1996 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
1997                        const char **upstream_name)
1998 {
1999         unsigned char sha1[20];
2000         struct commit *ours, *theirs;
2001         struct rev_info revs;
2002         const char *base;
2003         struct argv_array argv = ARGV_ARRAY_INIT;
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         argv_array_push(&argv, ""); /* ignored */
2033         argv_array_push(&argv, "--left-right");
2034         argv_array_pushf(&argv, "%s...%s",
2035                          sha1_to_hex(ours->object.sha1),
2036                          sha1_to_hex(theirs->object.sha1));
2037         argv_array_push(&argv, "--");
2038
2039         init_revisions(&revs, NULL);
2040         setup_revisions(argv.argc, argv.argv, &revs, NULL);
2041         if (prepare_revision_walk(&revs))
2042                 die("revision walk setup failed");
2043
2044         /* ... and count the commits on each side. */
2045         *num_ours = 0;
2046         *num_theirs = 0;
2047         while (1) {
2048                 struct commit *c = get_revision(&revs);
2049                 if (!c)
2050                         break;
2051                 if (c->object.flags & SYMMETRIC_LEFT)
2052                         (*num_ours)++;
2053                 else
2054                         (*num_theirs)++;
2055         }
2056
2057         /* clear object flags smudged by the above traversal */
2058         clear_commit_marks(ours, ALL_REV_FLAGS);
2059         clear_commit_marks(theirs, ALL_REV_FLAGS);
2060
2061         argv_array_clear(&argv);
2062         return 0;
2063 }
2064
2065 /*
2066  * Return true when there is anything to report, otherwise false.
2067  */
2068 int format_tracking_info(struct branch *branch, struct strbuf *sb)
2069 {
2070         int ours, theirs;
2071         const char *full_base;
2072         char *base;
2073         int upstream_is_gone = 0;
2074
2075         if (stat_tracking_info(branch, &ours, &theirs, &full_base) < 0) {
2076                 if (!full_base)
2077                         return 0;
2078                 upstream_is_gone = 1;
2079         }
2080
2081         base = shorten_unambiguous_ref(full_base, 0);
2082         if (upstream_is_gone) {
2083                 strbuf_addf(sb,
2084                         _("Your branch is based on '%s', but the upstream is gone.\n"),
2085                         base);
2086                 if (advice_status_hints)
2087                         strbuf_addf(sb,
2088                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
2089         } else if (!ours && !theirs) {
2090                 strbuf_addf(sb,
2091                         _("Your branch is up-to-date with '%s'.\n"),
2092                         base);
2093         } else if (!theirs) {
2094                 strbuf_addf(sb,
2095                         Q_("Your branch is ahead of '%s' by %d commit.\n",
2096                            "Your branch is ahead of '%s' by %d commits.\n",
2097                            ours),
2098                         base, ours);
2099                 if (advice_status_hints)
2100                         strbuf_addf(sb,
2101                                 _("  (use \"git push\" to publish your local commits)\n"));
2102         } else if (!ours) {
2103                 strbuf_addf(sb,
2104                         Q_("Your branch is behind '%s' by %d commit, "
2105                                "and can be fast-forwarded.\n",
2106                            "Your branch is behind '%s' by %d commits, "
2107                                "and can be fast-forwarded.\n",
2108                            theirs),
2109                         base, theirs);
2110                 if (advice_status_hints)
2111                         strbuf_addf(sb,
2112                                 _("  (use \"git pull\" to update your local branch)\n"));
2113         } else {
2114                 strbuf_addf(sb,
2115                         Q_("Your branch and '%s' have diverged,\n"
2116                                "and have %d and %d different commit each, "
2117                                "respectively.\n",
2118                            "Your branch and '%s' have diverged,\n"
2119                                "and have %d and %d different commits each, "
2120                                "respectively.\n",
2121                            theirs),
2122                         base, ours, theirs);
2123                 if (advice_status_hints)
2124                         strbuf_addf(sb,
2125                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
2126         }
2127         free(base);
2128         return 1;
2129 }
2130
2131 static int one_local_ref(const char *refname, const struct object_id *oid,
2132                          int flag, void *cb_data)
2133 {
2134         struct ref ***local_tail = cb_data;
2135         struct ref *ref;
2136         int len;
2137
2138         /* we already know it starts with refs/ to get here */
2139         if (check_refname_format(refname + 5, 0))
2140                 return 0;
2141
2142         len = strlen(refname) + 1;
2143         ref = xcalloc(1, sizeof(*ref) + len);
2144         hashcpy(ref->new_sha1, oid->hash);
2145         memcpy(ref->name, refname, len);
2146         **local_tail = ref;
2147         *local_tail = &ref->next;
2148         return 0;
2149 }
2150
2151 struct ref *get_local_heads(void)
2152 {
2153         struct ref *local_refs = NULL, **local_tail = &local_refs;
2154
2155         for_each_ref(one_local_ref, &local_tail);
2156         return local_refs;
2157 }
2158
2159 struct ref *guess_remote_head(const struct ref *head,
2160                               const struct ref *refs,
2161                               int all)
2162 {
2163         const struct ref *r;
2164         struct ref *list = NULL;
2165         struct ref **tail = &list;
2166
2167         if (!head)
2168                 return NULL;
2169
2170         /*
2171          * Some transports support directly peeking at
2172          * where HEAD points; if that is the case, then
2173          * we don't have to guess.
2174          */
2175         if (head->symref)
2176                 return copy_ref(find_ref_by_name(refs, head->symref));
2177
2178         /* If refs/heads/master could be right, it is. */
2179         if (!all) {
2180                 r = find_ref_by_name(refs, "refs/heads/master");
2181                 if (r && !hashcmp(r->old_sha1, head->old_sha1))
2182                         return copy_ref(r);
2183         }
2184
2185         /* Look for another ref that points there */
2186         for (r = refs; r; r = r->next) {
2187                 if (r != head &&
2188                     starts_with(r->name, "refs/heads/") &&
2189                     !hashcmp(r->old_sha1, head->old_sha1)) {
2190                         *tail = copy_ref(r);
2191                         tail = &((*tail)->next);
2192                         if (!all)
2193                                 break;
2194                 }
2195         }
2196
2197         return list;
2198 }
2199
2200 struct stale_heads_info {
2201         struct string_list *ref_names;
2202         struct ref **stale_refs_tail;
2203         struct refspec *refs;
2204         int ref_count;
2205 };
2206
2207 static int get_stale_heads_cb(const char *refname, const struct object_id *oid,
2208                               int flags, void *cb_data)
2209 {
2210         struct stale_heads_info *info = cb_data;
2211         struct string_list matches = STRING_LIST_INIT_DUP;
2212         struct refspec query;
2213         int i, stale = 1;
2214         memset(&query, 0, sizeof(struct refspec));
2215         query.dst = (char *)refname;
2216
2217         query_refspecs_multiple(info->refs, info->ref_count, &query, &matches);
2218         if (matches.nr == 0)
2219                 goto clean_exit; /* No matches */
2220
2221         /*
2222          * If we did find a suitable refspec and it's not a symref and
2223          * it's not in the list of refs that currently exist in that
2224          * remote, we consider it to be stale. In order to deal with
2225          * overlapping refspecs, we need to go over all of the
2226          * matching refs.
2227          */
2228         if (flags & REF_ISSYMREF)
2229                 goto clean_exit;
2230
2231         for (i = 0; stale && i < matches.nr; i++)
2232                 if (string_list_has_string(info->ref_names, matches.items[i].string))
2233                         stale = 0;
2234
2235         if (stale) {
2236                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2237                 hashcpy(ref->new_sha1, oid->hash);
2238         }
2239
2240 clean_exit:
2241         string_list_clear(&matches, 0);
2242         return 0;
2243 }
2244
2245 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
2246 {
2247         struct ref *ref, *stale_refs = NULL;
2248         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2249         struct stale_heads_info info;
2250
2251         info.ref_names = &ref_names;
2252         info.stale_refs_tail = &stale_refs;
2253         info.refs = refs;
2254         info.ref_count = ref_count;
2255         for (ref = fetch_map; ref; ref = ref->next)
2256                 string_list_append(&ref_names, ref->name);
2257         string_list_sort(&ref_names);
2258         for_each_ref(get_stale_heads_cb, &info);
2259         string_list_clear(&ref_names, 0);
2260         return stale_refs;
2261 }
2262
2263 /*
2264  * Compare-and-swap
2265  */
2266 static void clear_cas_option(struct push_cas_option *cas)
2267 {
2268         int i;
2269
2270         for (i = 0; i < cas->nr; i++)
2271                 free(cas->entry[i].refname);
2272         free(cas->entry);
2273         memset(cas, 0, sizeof(*cas));
2274 }
2275
2276 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2277                                       const char *refname,
2278                                       size_t refnamelen)
2279 {
2280         struct push_cas *entry;
2281         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2282         entry = &cas->entry[cas->nr++];
2283         memset(entry, 0, sizeof(*entry));
2284         entry->refname = xmemdupz(refname, refnamelen);
2285         return entry;
2286 }
2287
2288 int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2289 {
2290         const char *colon;
2291         struct push_cas *entry;
2292
2293         if (unset) {
2294                 /* "--no-<option>" */
2295                 clear_cas_option(cas);
2296                 return 0;
2297         }
2298
2299         if (!arg) {
2300                 /* just "--<option>" */
2301                 cas->use_tracking_for_rest = 1;
2302                 return 0;
2303         }
2304
2305         /* "--<option>=refname" or "--<option>=refname:value" */
2306         colon = strchrnul(arg, ':');
2307         entry = add_cas_entry(cas, arg, colon - arg);
2308         if (!*colon)
2309                 entry->use_tracking = 1;
2310         else if (get_sha1(colon + 1, entry->expect))
2311                 return error("cannot parse expected object name '%s'", colon + 1);
2312         return 0;
2313 }
2314
2315 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2316 {
2317         return parse_push_cas_option(opt->value, arg, unset);
2318 }
2319
2320 int is_empty_cas(const struct push_cas_option *cas)
2321 {
2322         return !cas->use_tracking_for_rest && !cas->nr;
2323 }
2324
2325 /*
2326  * Look at remote.fetch refspec and see if we have a remote
2327  * tracking branch for the refname there.  Fill its current
2328  * value in sha1[].
2329  * If we cannot do so, return negative to signal an error.
2330  */
2331 static int remote_tracking(struct remote *remote, const char *refname,
2332                            unsigned char sha1[20])
2333 {
2334         char *dst;
2335
2336         dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
2337         if (!dst)
2338                 return -1; /* no tracking ref for refname at remote */
2339         if (read_ref(dst, sha1))
2340                 return -1; /* we know what the tracking ref is but we cannot read it */
2341         return 0;
2342 }
2343
2344 static void apply_cas(struct push_cas_option *cas,
2345                       struct remote *remote,
2346                       struct ref *ref)
2347 {
2348         int i;
2349
2350         /* Find an explicit --<option>=<name>[:<value>] entry */
2351         for (i = 0; i < cas->nr; i++) {
2352                 struct push_cas *entry = &cas->entry[i];
2353                 if (!refname_match(entry->refname, ref->name))
2354                         continue;
2355                 ref->expect_old_sha1 = 1;
2356                 if (!entry->use_tracking)
2357                         hashcpy(ref->old_sha1_expect, cas->entry[i].expect);
2358                 else if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2359                         ref->expect_old_no_trackback = 1;
2360                 return;
2361         }
2362
2363         /* Are we using "--<option>" to cover all? */
2364         if (!cas->use_tracking_for_rest)
2365                 return;
2366
2367         ref->expect_old_sha1 = 1;
2368         if (remote_tracking(remote, ref->name, ref->old_sha1_expect))
2369                 ref->expect_old_no_trackback = 1;
2370 }
2371
2372 void apply_push_cas(struct push_cas_option *cas,
2373                     struct remote *remote,
2374                     struct ref *remote_refs)
2375 {
2376         struct ref *ref;
2377         for (ref = remote_refs; ref; ref = ref->next)
2378                 apply_cas(cas, remote, ref);
2379 }