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) != 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_lf(&buf, f);
 285         fclose(f);
 286         strbuf_trim(&buf);
 287         if (!buf.len) {
 288                 strbuf_release(&buf);
 289                 return;
 290         }
 291
 292         remote->origin = REMOTE_BRANCHES;
 293
 294         /*
 295          * The branches file would have URL and optionally
 296          * #branch specified.  The "master" (or specified) branch is
 297          * fetched and stored in the local branch matching the
 298          * remote name.
 299          */
 300         frag = strchr(buf.buf, '#');
 301         if (frag)
 302                 *(frag++) = '\0';
 303         else
 304                 frag = "master";
 305
 306         add_url_alias(remote, strbuf_detach(&buf, NULL));
 307         add_fetch_refspec(remote, xstrfmt("refs/heads/%s:refs/heads/%s",
 308                                           frag, remote->name));
 309
 310         /*
 311          * Cogito compatible push: push current HEAD to remote #branch
 312          * (master if missing)
 313          */
 314         add_push_refspec(remote, xstrfmt("HEAD:refs/heads/%s", frag));
 315         remote->fetch_tags = 1; /* always auto-follow */
 316 }
 317
 318 static int handle_config(const char *key, const char *value, void *cb)
 319 {
 320         const char *name;
 321         int namelen;
 322         const char *subkey;
 323         struct remote *remote;
 324         struct branch *branch;
 325         if (parse_config_key(key, "branch", &name, &namelen, &subkey) >= 0) {
 326                 if (!name)
 327                         return 0;
 328                 branch = make_branch(name, namelen);
 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 (parse_config_key(key, "url", &name, &namelen, &subkey) >= 0) {
 341                 struct rewrite *rewrite;
 342                 if (!name)
 343                         return 0;
 344                 if (!strcmp(subkey, "insteadof")) {
 345                         rewrite = make_rewrite(&rewrites, name, namelen);
 346                         if (!value)
 347                                 return config_error_nonbool(key);
 348                         add_instead_of(rewrite, xstrdup(value));
 349                 } else if (!strcmp(subkey, "pushinsteadof")) {
 350                         rewrite = make_rewrite(&rewrites_push, name, namelen);
 351                         if (!value)
 352                                 return config_error_nonbool(key);
 353                         add_instead_of(rewrite, xstrdup(value));
 354                 }
 355         }
 356
 357         if (parse_config_key(key, "remote", &name, &namelen, &subkey) < 0)
 358                 return 0;
 359
 360         /* Handle remote.* variables */
 361         if (!name && !strcmp(subkey, "pushdefault"))
 362                 return git_config_string(&pushremote_name, key, value);
 363
 364         if (!name)
 365                 return 0;
 366         /* Handle remote.<name>.* variables */
 367         if (*name == '/') {
 368                 warning("Config remote shorthand cannot begin with '/': %s",
 369                         name);
 370                 return 0;
 371         }
 372         remote = make_remote(name, namelen);
 373         remote->origin = REMOTE_CONFIG;
 374         if (!strcmp(subkey, "mirror"))
 375                 remote->mirror = git_config_bool(key, value);
 376         else if (!strcmp(subkey, "skipdefaultupdate"))
 377                 remote->skip_default_update = git_config_bool(key, value);
 378         else if (!strcmp(subkey, "skipfetchall"))
 379                 remote->skip_default_update = git_config_bool(key, value);
 380         else if (!strcmp(subkey, "prune"))
 381                 remote->prune = git_config_bool(key, value);
 382         else if (!strcmp(subkey, "url")) {
 383                 const char *v;
 384                 if (git_config_string(&v, key, value))
 385                         return -1;
 386                 add_url(remote, v);
 387         } else if (!strcmp(subkey, "pushurl")) {
 388                 const char *v;
 389                 if (git_config_string(&v, key, value))
 390                         return -1;
 391                 add_pushurl(remote, v);
 392         } else if (!strcmp(subkey, "push")) {
 393                 const char *v;
 394                 if (git_config_string(&v, key, value))
 395                         return -1;
 396                 add_push_refspec(remote, v);
 397         } else if (!strcmp(subkey, "fetch")) {
 398                 const char *v;
 399                 if (git_config_string(&v, key, value))
 400                         return -1;
 401                 add_fetch_refspec(remote, v);
 402         } else if (!strcmp(subkey, "receivepack")) {
 403                 const char *v;
 404                 if (git_config_string(&v, key, value))
 405                         return -1;
 406                 if (!remote->receivepack)
 407                         remote->receivepack = v;
 408                 else
 409                         error("more than one receivepack given, using the first");
 410         } else if (!strcmp(subkey, "uploadpack")) {
 411                 const char *v;
 412                 if (git_config_string(&v, key, value))
 413                         return -1;
 414                 if (!remote->uploadpack)
 415                         remote->uploadpack = v;
 416                 else
 417                         error("more than one uploadpack given, using the first");
 418         } else if (!strcmp(subkey, "tagopt")) {
 419                 if (!strcmp(value, "--no-tags"))
 420                         remote->fetch_tags = -1;
 421                 else if (!strcmp(value, "--tags"))
 422                         remote->fetch_tags = 2;
 423         } else if (!strcmp(subkey, "proxy")) {
 424                 return git_config_string((const char **)&remote->http_proxy,
 425                                          key, value);
 426         } else if (!strcmp(subkey, "proxyauthmethod")) {
 427                 return git_config_string((const char **)&remote->http_proxy_authmethod,
 428                                          key, value);
 429         } else if (!strcmp(subkey, "vcs")) {
 430                 return git_config_string(&remote->foreign_vcs, key, value);
 431         }
 432         return 0;
 433 }
 434
 435 static void alias_all_urls(void)
 436 {
 437         int i, j;
 438         for (i = 0; i < remotes_nr; i++) {
 439                 int add_pushurl_aliases;
 440                 if (!remotes[i])
 441                         continue;
 442                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 443                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 444                 }
 445                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 446                 for (j = 0; j < remotes[i]->url_nr; j++) {
 447                         if (add_pushurl_aliases)
 448                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 449                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 450                 }
 451         }
 452 }
 453
 454 static void read_config(void)
 455 {
 456         static int loaded;
 457         struct object_id oid;
 458         int flag;
 459
 460         if (loaded)
 461                 return;
 462         loaded = 1;
 463
 464         current_branch = NULL;
 465         if (startup_info->have_repository) {
 466                 const char *head_ref = resolve_ref_unsafe("HEAD", 0, oid.hash, &flag);
 467                 if (head_ref && (flag & REF_ISSYMREF) &&
 468                     skip_prefix(head_ref, "refs/heads/", &head_ref)) {
 469                         current_branch = make_branch(head_ref, 0);
 470                 }
 471         }
 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                         struct object_id unused;
 547
 548                         /* LHS */
 549                         if (!*rs[i].src)
 550                                 ; /* empty is ok; it means "HEAD" */
 551                         else if (llen == GIT_SHA1_HEXSZ && !get_oid_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(struct remote *remote)
 718 {
 719         return remote && remote->origin;
 720 }
 721
 722 int for_each_remote(each_remote_fn fn, void *priv)
 723 {
 724         int i, result = 0;
 725         read_config();
 726         for (i = 0; i < remotes_nr && !result; i++) {
 727                 struct remote *r = remotes[i];
 728                 if (!r)
 729                         continue;
 730                 if (!r->fetch)
 731                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 732                                                        r->fetch_refspec);
 733                 if (!r->push)
 734                         r->push = parse_push_refspec(r->push_refspec_nr,
 735                                                      r->push_refspec);
 736                 result = fn(r, priv);
 737         }
 738         return result;
 739 }
 740
 741 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
 742 {
 743         if (strcmp(ref1->name, ref2->name)) {
 744                 if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 745                     ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
 746                         die(_("Cannot fetch both %s and %s to %s"),
 747                             ref1->name, ref2->name, ref2->peer_ref->name);
 748                 } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 749                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 750                         warning(_("%s usually tracks %s, not %s"),
 751                                 ref2->peer_ref->name, ref2->name, ref1->name);
 752                 } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
 753                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 754                         die(_("%s tracks both %s and %s"),
 755                             ref2->peer_ref->name, ref1->name, ref2->name);
 756                 } else {
 757                         /*
 758                          * This last possibility doesn't occur because
 759                          * FETCH_HEAD_IGNORE entries always appear at
 760                          * the end of the list.
 761                          */
 762                         die(_("Internal error"));
 763                 }
 764         }
 765         free(ref2->peer_ref);
 766         free(ref2);
 767 }
 768
 769 struct ref *ref_remove_duplicates(struct ref *ref_map)
 770 {
 771         struct string_list refs = STRING_LIST_INIT_NODUP;
 772         struct ref *retval = NULL;
 773         struct ref **p = &retval;
 774
 775         while (ref_map) {
 776                 struct ref *ref = ref_map;
 777
 778                 ref_map = ref_map->next;
 779                 ref->next = NULL;
 780
 781                 if (!ref->peer_ref) {
 782                         *p = ref;
 783                         p = &ref->next;
 784                 } else {
 785                         struct string_list_item *item =
 786                                 string_list_insert(&refs, ref->peer_ref->name);
 787
 788                         if (item->util) {
 789                                 /* Entry already existed */
 790                                 handle_duplicate((struct ref *)item->util, ref);
 791                         } else {
 792                                 *p = ref;
 793                                 p = &ref->next;
 794                                 item->util = ref;
 795                         }
 796                 }
 797         }
 798
 799         string_list_clear(&refs, 0);
 800         return retval;
 801 }
 802
 803 int remote_has_url(struct remote *remote, const char *url)
 804 {
 805         int i;
 806         for (i = 0; i < remote->url_nr; i++) {
 807                 if (!strcmp(remote->url[i], url))
 808                         return 1;
 809         }
 810         return 0;
 811 }
 812
 813 static int match_name_with_pattern(const char *key, const char *name,
 814                                    const char *value, char **result)
 815 {
 816         const char *kstar = strchr(key, '*');
 817         size_t klen;
 818         size_t ksuffixlen;
 819         size_t namelen;
 820         int ret;
 821         if (!kstar)
 822                 die("Key '%s' of pattern had no '*'", key);
 823         klen = kstar - key;
 824         ksuffixlen = strlen(kstar + 1);
 825         namelen = strlen(name);
 826         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 827                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 828         if (ret && value) {
 829                 struct strbuf sb = STRBUF_INIT;
 830                 const char *vstar = strchr(value, '*');
 831                 if (!vstar)
 832                         die("Value '%s' of pattern has no '*'", value);
 833                 strbuf_add(&sb, value, vstar - value);
 834                 strbuf_add(&sb, name + klen, namelen - klen - ksuffixlen);
 835                 strbuf_addstr(&sb, vstar + 1);
 836                 *result = strbuf_detach(&sb, NULL);
 837         }
 838         return ret;
 839 }
 840
 841 static void query_refspecs_multiple(struct refspec *refs, int ref_count, struct refspec *query, struct string_list *results)
 842 {
 843         int i;
 844         int find_src = !query->src;
 845
 846         if (find_src && !query->dst)
 847                 error("query_refspecs_multiple: need either src or dst");
 848
 849         for (i = 0; i < ref_count; i++) {
 850                 struct refspec *refspec = &refs[i];
 851                 const char *key = find_src ? refspec->dst : refspec->src;
 852                 const char *value = find_src ? refspec->src : refspec->dst;
 853                 const char *needle = find_src ? query->dst : query->src;
 854                 char **result = find_src ? &query->src : &query->dst;
 855
 856                 if (!refspec->dst)
 857                         continue;
 858                 if (refspec->pattern) {
 859                         if (match_name_with_pattern(key, needle, value, result))
 860                                 string_list_append_nodup(results, *result);
 861                 } else if (!strcmp(needle, key)) {
 862                         string_list_append(results, value);
 863                 }
 864         }
 865 }
 866
 867 int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
 868 {
 869         int i;
 870         int find_src = !query->src;
 871         const char *needle = find_src ? query->dst : query->src;
 872         char **result = find_src ? &query->src : &query->dst;
 873
 874         if (find_src && !query->dst)
 875                 return error("query_refspecs: need either src or dst");
 876
 877         for (i = 0; i < ref_count; i++) {
 878                 struct refspec *refspec = &refs[i];
 879                 const char *key = find_src ? refspec->dst : refspec->src;
 880                 const char *value = find_src ? refspec->src : refspec->dst;
 881
 882                 if (!refspec->dst)
 883                         continue;
 884                 if (refspec->pattern) {
 885                         if (match_name_with_pattern(key, needle, value, result)) {
 886                                 query->force = refspec->force;
 887                                 return 0;
 888                         }
 889                 } else if (!strcmp(needle, key)) {
 890                         *result = xstrdup(value);
 891                         query->force = refspec->force;
 892                         return 0;
 893                 }
 894         }
 895         return -1;
 896 }
 897
 898 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 899                      const char *name)
 900 {
 901         struct refspec query;
 902
 903         memset(&query, 0, sizeof(struct refspec));
 904         query.src = (char *)name;
 905
 906         if (query_refspecs(refspecs, nr_refspec, &query))
 907                 return NULL;
 908
 909         return query.dst;
 910 }
 911
 912 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 913 {
 914         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
 915 }
 916
 917 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 918                 const char *name)
 919 {
 920         size_t len = strlen(name);
 921         struct ref *ref = xcalloc(1, st_add4(sizeof(*ref), prefixlen, len, 1));
 922         memcpy(ref->name, prefix, prefixlen);
 923         memcpy(ref->name + prefixlen, name, len);
 924         return ref;
 925 }
 926
 927 struct ref *alloc_ref(const char *name)
 928 {
 929         return alloc_ref_with_prefix("", 0, name);
 930 }
 931
 932 struct ref *copy_ref(const struct ref *ref)
 933 {
 934         struct ref *cpy;
 935         size_t len;
 936         if (!ref)
 937                 return NULL;
 938         len = st_add3(sizeof(struct ref), strlen(ref->name), 1);
 939         cpy = xmalloc(len);
 940         memcpy(cpy, ref, len);
 941         cpy->next = NULL;
 942         cpy->symref = xstrdup_or_null(ref->symref);
 943         cpy->remote_status = xstrdup_or_null(ref->remote_status);
 944         cpy->peer_ref = copy_ref(ref->peer_ref);
 945         return cpy;
 946 }
 947
 948 struct ref *copy_ref_list(const struct ref *ref)
 949 {
 950         struct ref *ret = NULL;
 951         struct ref **tail = &ret;
 952         while (ref) {
 953                 *tail = copy_ref(ref);
 954                 ref = ref->next;
 955                 tail = &((*tail)->next);
 956         }
 957         return ret;
 958 }
 959
 960 static void free_ref(struct ref *ref)
 961 {
 962         if (!ref)
 963                 return;
 964         free_ref(ref->peer_ref);
 965         free(ref->remote_status);
 966         free(ref->symref);
 967         free(ref);
 968 }
 969
 970 void free_refs(struct ref *ref)
 971 {
 972         struct ref *next;
 973         while (ref) {
 974                 next = ref->next;
 975                 free_ref(ref);
 976                 ref = next;
 977         }
 978 }
 979
 980 int ref_compare_name(const void *va, const void *vb)
 981 {
 982         const struct ref *a = va, *b = vb;
 983         return strcmp(a->name, b->name);
 984 }
 985
 986 static void *ref_list_get_next(const void *a)
 987 {
 988         return ((const struct ref *)a)->next;
 989 }
 990
 991 static void ref_list_set_next(void *a, void *next)
 992 {
 993         ((struct ref *)a)->next = next;
 994 }
 995
 996 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
 997 {
 998         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
 999 }
1000
1001 int count_refspec_match(const char *pattern,
1002                         struct ref *refs,
1003                         struct ref **matched_ref)
1004 {
1005         int patlen = strlen(pattern);
1006         struct ref *matched_weak = NULL;
1007         struct ref *matched = NULL;
1008         int weak_match = 0;
1009         int match = 0;
1010
1011         for (weak_match = match = 0; refs; refs = refs->next) {
1012                 char *name = refs->name;
1013                 int namelen = strlen(name);
1014
1015                 if (!refname_match(pattern, name))
1016                         continue;
1017
1018                 /* A match is "weak" if it is with refs outside
1019                  * heads or tags, and did not specify the pattern
1020                  * in full (e.g. "refs/remotes/origin/master") or at
1021                  * least from the toplevel (e.g. "remotes/origin/master");
1022                  * otherwise "git push $URL master" would result in
1023                  * ambiguity between remotes/origin/master and heads/master
1024                  * at the remote site.
1025                  */
1026                 if (namelen != patlen &&
1027                     patlen != namelen - 5 &&
1028                     !starts_with(name, "refs/heads/") &&
1029                     !starts_with(name, "refs/tags/")) {
1030                         /* We want to catch the case where only weak
1031                          * matches are found and there are multiple
1032                          * matches, and where more than one strong
1033                          * matches are found, as ambiguous.  One
1034                          * strong match with zero or more weak matches
1035                          * are acceptable as a unique match.
1036                          */
1037                         matched_weak = refs;
1038                         weak_match++;
1039                 }
1040                 else {
1041                         matched = refs;
1042                         match++;
1043                 }
1044         }
1045         if (!matched) {
1046                 if (matched_ref)
1047                         *matched_ref = matched_weak;
1048                 return weak_match;
1049         }
1050         else {
1051                 if (matched_ref)
1052                         *matched_ref = matched;
1053                 return match;
1054         }
1055 }
1056
1057 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1058 {
1059         **tail = ref;
1060         while (ref->next)
1061                 ref = ref->next;
1062         *tail = &ref->next;
1063 }
1064
1065 static struct ref *alloc_delete_ref(void)
1066 {
1067         struct ref *ref = alloc_ref("(delete)");
1068         oidclr(&ref->new_oid);
1069         return ref;
1070 }
1071
1072 static int try_explicit_object_name(const char *name,
1073                                     struct ref **match)
1074 {
1075         struct object_id oid;
1076
1077         if (!*name) {
1078                 if (match)
1079                         *match = alloc_delete_ref();
1080                 return 0;
1081         }
1082
1083         if (get_sha1(name, oid.hash))
1084                 return -1;
1085
1086         if (match) {
1087                 *match = alloc_ref(name);
1088                 oidcpy(&(*match)->new_oid, &oid);
1089         }
1090         return 0;
1091 }
1092
1093 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1094 {
1095         struct ref *ret = alloc_ref(name);
1096         tail_link_ref(ret, tail);
1097         return ret;
1098 }
1099
1100 static char *guess_ref(const char *name, struct ref *peer)
1101 {
1102         struct strbuf buf = STRBUF_INIT;
1103         struct object_id oid;
1104
1105         const char *r = resolve_ref_unsafe(peer->name, RESOLVE_REF_READING,
1106                                            oid.hash, NULL);
1107         if (!r)
1108                 return NULL;
1109
1110         if (starts_with(r, "refs/heads/"))
1111                 strbuf_addstr(&buf, "refs/heads/");
1112         else if (starts_with(r, "refs/tags/"))
1113                 strbuf_addstr(&buf, "refs/tags/");
1114         else
1115                 return NULL;
1116
1117         strbuf_addstr(&buf, name);
1118         return strbuf_detach(&buf, NULL);
1119 }
1120
1121 static int match_explicit_lhs(struct ref *src,
1122                               struct refspec *rs,
1123                               struct ref **match,
1124                               int *allocated_match)
1125 {
1126         switch (count_refspec_match(rs->src, src, match)) {
1127         case 1:
1128                 if (allocated_match)
1129                         *allocated_match = 0;
1130                 return 0;
1131         case 0:
1132                 /* The source could be in the get_sha1() format
1133                  * not a reference name.  :refs/other is a
1134                  * way to delete 'other' ref at the remote end.
1135                  */
1136                 if (try_explicit_object_name(rs->src, match) < 0)
1137                         return error("src refspec %s does not match any.", rs->src);
1138                 if (allocated_match)
1139                         *allocated_match = 1;
1140                 return 0;
1141         default:
1142                 return error("src refspec %s matches more than one.", rs->src);
1143         }
1144 }
1145
1146 static int match_explicit(struct ref *src, struct ref *dst,
1147                           struct ref ***dst_tail,
1148                           struct refspec *rs)
1149 {
1150         struct ref *matched_src, *matched_dst;
1151         int allocated_src;
1152
1153         const char *dst_value = rs->dst;
1154         char *dst_guess;
1155
1156         if (rs->pattern || rs->matching)
1157                 return 0;
1158
1159         matched_src = matched_dst = NULL;
1160         if (match_explicit_lhs(src, rs, &matched_src, &allocated_src) < 0)
1161                 return -1;
1162
1163         if (!dst_value) {
1164                 struct object_id oid;
1165                 int flag;
1166
1167                 dst_value = resolve_ref_unsafe(matched_src->name,
1168                                                RESOLVE_REF_READING,
1169                                                oid.hash, &flag);
1170                 if (!dst_value ||
1171                     ((flag & REF_ISSYMREF) &&
1172                      !starts_with(dst_value, "refs/heads/")))
1173                         die("%s cannot be resolved to branch.",
1174                             matched_src->name);
1175         }
1176
1177         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1178         case 1:
1179                 break;
1180         case 0:
1181                 if (starts_with(dst_value, "refs/"))
1182                         matched_dst = make_linked_ref(dst_value, dst_tail);
1183                 else if (is_null_oid(&matched_src->new_oid))
1184                         error("unable to delete '%s': remote ref does not exist",
1185                               dst_value);
1186                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1187                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1188                 else
1189                         error("unable to push to unqualified destination: %s\n"
1190                               "The destination refspec neither matches an "
1191                               "existing ref on the remote nor\n"
1192                               "begins with refs/, and we are unable to "
1193                               "guess a prefix based on the source ref.",
1194                               dst_value);
1195                 break;
1196         default:
1197                 matched_dst = NULL;
1198                 error("dst refspec %s matches more than one.",
1199                       dst_value);
1200                 break;
1201         }
1202         if (!matched_dst)
1203                 return -1;
1204         if (matched_dst->peer_ref)
1205                 return error("dst ref %s receives from more than one src.",
1206                       matched_dst->name);
1207         else {
1208                 matched_dst->peer_ref = allocated_src ?
1209                                         matched_src :
1210                                         copy_ref(matched_src);
1211                 matched_dst->force = rs->force;
1212         }
1213         return 0;
1214 }
1215
1216 static int match_explicit_refs(struct ref *src, struct ref *dst,
1217                                struct ref ***dst_tail, struct refspec *rs,
1218                                int rs_nr)
1219 {
1220         int i, errs;
1221         for (i = errs = 0; i < rs_nr; i++)
1222                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1223         return errs;
1224 }
1225
1226 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1227                 int send_mirror, int direction, const struct refspec **ret_pat)
1228 {
1229         const struct refspec *pat;
1230         char *name;
1231         int i;
1232         int matching_refs = -1;
1233         for (i = 0; i < rs_nr; i++) {
1234                 if (rs[i].matching &&
1235                     (matching_refs == -1 || rs[i].force)) {
1236                         matching_refs = i;
1237                         continue;
1238                 }
1239
1240                 if (rs[i].pattern) {
1241                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1242                         int match;
1243                         if (direction == FROM_SRC)
1244                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1245                         else
1246                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1247                         if (match) {
1248                                 matching_refs = i;
1249                                 break;
1250                         }
1251                 }
1252         }
1253         if (matching_refs == -1)
1254                 return NULL;
1255
1256         pat = rs + matching_refs;
1257         if (pat->matching) {
1258                 /*
1259                  * "matching refs"; traditionally we pushed everything
1260                  * including refs outside refs/heads/ hierarchy, but
1261                  * that does not make much sense these days.
1262                  */
1263                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1264                         return NULL;
1265                 name = xstrdup(ref->name);
1266         }
1267         if (ret_pat)
1268                 *ret_pat = pat;
1269         return name;
1270 }
1271
1272 static struct ref **tail_ref(struct ref **head)
1273 {
1274         struct ref **tail = head;
1275         while (*tail)
1276                 tail = &((*tail)->next);
1277         return tail;
1278 }
1279
1280 struct tips {
1281         struct commit **tip;
1282         int nr, alloc;
1283 };
1284
1285 static void add_to_tips(struct tips *tips, const struct object_id *oid)
1286 {
1287         struct commit *commit;
1288
1289         if (is_null_oid(oid))
1290                 return;
1291         commit = lookup_commit_reference_gently(oid->hash, 1);
1292         if (!commit || (commit->object.flags & TMP_MARK))
1293                 return;
1294         commit->object.flags |= TMP_MARK;
1295         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1296         tips->tip[tips->nr++] = commit;
1297 }
1298
1299 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1300 {
1301         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1302         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1303         struct string_list_item *item;
1304         struct ref *ref;
1305         struct tips sent_tips;
1306
1307         /*
1308          * Collect everything we know they would have at the end of
1309          * this push, and collect all tags they have.
1310          */
1311         memset(&sent_tips, 0, sizeof(sent_tips));
1312         for (ref = *dst; ref; ref = ref->next) {
1313                 if (ref->peer_ref &&
1314                     !is_null_oid(&ref->peer_ref->new_oid))
1315                         add_to_tips(&sent_tips, &ref->peer_ref->new_oid);
1316                 else
1317                         add_to_tips(&sent_tips, &ref->old_oid);
1318                 if (starts_with(ref->name, "refs/tags/"))
1319                         string_list_append(&dst_tag, ref->name);
1320         }
1321         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1322
1323         string_list_sort(&dst_tag);
1324
1325         /* Collect tags they do not have. */
1326         for (ref = src; ref; ref = ref->next) {
1327                 if (!starts_with(ref->name, "refs/tags/"))
1328                         continue; /* not a tag */
1329                 if (string_list_has_string(&dst_tag, ref->name))
1330                         continue; /* they already have it */
1331                 if (sha1_object_info(ref->new_oid.hash, NULL) != OBJ_TAG)
1332                         continue; /* be conservative */
1333                 item = string_list_append(&src_tag, ref->name);
1334                 item->util = ref;
1335         }
1336         string_list_clear(&dst_tag, 0);
1337
1338         /*
1339          * At this point, src_tag lists tags that are missing from
1340          * dst, and sent_tips lists the tips we are pushing or those
1341          * that we know they already have. An element in the src_tag
1342          * that is an ancestor of any of the sent_tips needs to be
1343          * sent to the other side.
1344          */
1345         if (sent_tips.nr) {
1346                 for_each_string_list_item(item, &src_tag) {
1347                         struct ref *ref = item->util;
1348                         struct ref *dst_ref;
1349                         struct commit *commit;
1350
1351                         if (is_null_oid(&ref->new_oid))
1352                                 continue;
1353                         commit = lookup_commit_reference_gently(ref->new_oid.hash, 1);
1354                         if (!commit)
1355                                 /* not pushing a commit, which is not an error */
1356                                 continue;
1357
1358                         /*
1359                          * Is this tag, which they do not have, reachable from
1360                          * any of the commits we are sending?
1361                          */
1362                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1363                                 continue;
1364
1365                         /* Add it in */
1366                         dst_ref = make_linked_ref(ref->name, dst_tail);
1367                         oidcpy(&dst_ref->new_oid, &ref->new_oid);
1368                         dst_ref->peer_ref = copy_ref(ref);
1369                 }
1370         }
1371         string_list_clear(&src_tag, 0);
1372         free(sent_tips.tip);
1373 }
1374
1375 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1376 {
1377         for ( ; list; list = list->next)
1378                 if (!strcmp(list->name, name))
1379                         return (struct ref *)list;
1380         return NULL;
1381 }
1382
1383 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1384 {
1385         for ( ; ref; ref = ref->next)
1386                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1387
1388         string_list_sort(ref_index);
1389 }
1390
1391 /*
1392  * Given only the set of local refs, sanity-check the set of push
1393  * refspecs. We can't catch all errors that match_push_refs would,
1394  * but we can catch some errors early before even talking to the
1395  * remote side.
1396  */
1397 int check_push_refs(struct ref *src, int nr_refspec, const char **refspec_names)
1398 {
1399         struct refspec *refspec = parse_push_refspec(nr_refspec, refspec_names);
1400         int ret = 0;
1401         int i;
1402
1403         for (i = 0; i < nr_refspec; i++) {
1404                 struct refspec *rs = refspec + i;
1405
1406                 if (rs->pattern || rs->matching)
1407                         continue;
1408
1409                 ret |= match_explicit_lhs(src, rs, NULL, NULL);
1410         }
1411
1412         free_refspec(nr_refspec, refspec);
1413         return ret;
1414 }
1415
1416 /*
1417  * Given the set of refs the local repository has, the set of refs the
1418  * remote repository has, and the refspec used for push, determine
1419  * what remote refs we will update and with what value by setting
1420  * peer_ref (which object is being pushed) and force (if the push is
1421  * forced) in elements of "dst". The function may add new elements to
1422  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1423  */
1424 int match_push_refs(struct ref *src, struct ref **dst,
1425                     int nr_refspec, const char **refspec, int flags)
1426 {
1427         struct refspec *rs;
1428         int send_all = flags & MATCH_REFS_ALL;
1429         int send_mirror = flags & MATCH_REFS_MIRROR;
1430         int send_prune = flags & MATCH_REFS_PRUNE;
1431         int errs;
1432         static const char *default_refspec[] = { ":", NULL };
1433         struct ref *ref, **dst_tail = tail_ref(dst);
1434         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1435
1436         if (!nr_refspec) {
1437                 nr_refspec = 1;
1438                 refspec = default_refspec;
1439         }
1440         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1441         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1442
1443         /* pick the remainder */
1444         for (ref = src; ref; ref = ref->next) {
1445                 struct string_list_item *dst_item;
1446                 struct ref *dst_peer;
1447                 const struct refspec *pat = NULL;
1448                 char *dst_name;
1449
1450                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1451                 if (!dst_name)
1452                         continue;
1453
1454                 if (!dst_ref_index.nr)
1455                         prepare_ref_index(&dst_ref_index, *dst);
1456
1457                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1458                 dst_peer = dst_item ? dst_item->util : NULL;
1459                 if (dst_peer) {
1460                         if (dst_peer->peer_ref)
1461                                 /* We're already sending something to this ref. */
1462                                 goto free_name;
1463                 } else {
1464                         if (pat->matching && !(send_all || send_mirror))
1465                                 /*
1466                                  * Remote doesn't have it, and we have no
1467                                  * explicit pattern, and we don't have
1468                                  * --all or --mirror.
1469                                  */
1470                                 goto free_name;
1471
1472                         /* Create a new one and link it */
1473                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1474                         oidcpy(&dst_peer->new_oid, &ref->new_oid);
1475                         string_list_insert(&dst_ref_index,
1476                                 dst_peer->name)->util = dst_peer;
1477                 }
1478                 dst_peer->peer_ref = copy_ref(ref);
1479                 dst_peer->force = pat->force;
1480         free_name:
1481                 free(dst_name);
1482         }
1483
1484         string_list_clear(&dst_ref_index, 0);
1485
1486         if (flags & MATCH_REFS_FOLLOW_TAGS)
1487                 add_missing_tags(src, dst, &dst_tail);
1488
1489         if (send_prune) {
1490                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1491                 /* check for missing refs on the remote */
1492                 for (ref = *dst; ref; ref = ref->next) {
1493                         char *src_name;
1494
1495                         if (ref->peer_ref)
1496                                 /* We're already sending something to this ref. */
1497                                 continue;
1498
1499                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1500                         if (src_name) {
1501                                 if (!src_ref_index.nr)
1502                                         prepare_ref_index(&src_ref_index, src);
1503                                 if (!string_list_has_string(&src_ref_index,
1504                                             src_name))
1505                                         ref->peer_ref = alloc_delete_ref();
1506                                 free(src_name);
1507                         }
1508                 }
1509                 string_list_clear(&src_ref_index, 0);
1510         }
1511         if (errs)
1512                 return -1;
1513         return 0;
1514 }
1515
1516 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1517                              int force_update)
1518 {
1519         struct ref *ref;
1520
1521         for (ref = remote_refs; ref; ref = ref->next) {
1522                 int force_ref_update = ref->force || force_update;
1523                 int reject_reason = 0;
1524
1525                 if (ref->peer_ref)
1526                         oidcpy(&ref->new_oid, &ref->peer_ref->new_oid);
1527                 else if (!send_mirror)
1528                         continue;
1529
1530                 ref->deletion = is_null_oid(&ref->new_oid);
1531                 if (!ref->deletion &&
1532                         !oidcmp(&ref->old_oid, &ref->new_oid)) {
1533                         ref->status = REF_STATUS_UPTODATE;
1534                         continue;
1535                 }
1536
1537                 /*
1538                  * If the remote ref has moved and is now different
1539                  * from what we expect, reject any push.
1540                  *
1541                  * It also is an error if the user told us to check
1542                  * with the remote-tracking branch to find the value
1543                  * to expect, but we did not have such a tracking
1544                  * branch.
1545                  */
1546                 if (ref->expect_old_sha1) {
1547                         if (ref->expect_old_no_trackback ||
1548                             oidcmp(&ref->old_oid, &ref->old_oid_expect))
1549                                 reject_reason = REF_STATUS_REJECT_STALE;
1550                         else
1551                                 /* If the ref isn't stale then force the update. */
1552                                 force_ref_update = 1;
1553                 }
1554
1555                 /*
1556                  * If the update isn't already rejected then check
1557                  * the usual "must fast-forward" rules.
1558                  *
1559                  * Decide whether an individual refspec A:B can be
1560                  * pushed.  The push will succeed if any of the
1561                  * following are true:
1562                  *
1563                  * (1) the remote reference B does not exist
1564                  *
1565                  * (2) the remote reference B is being removed (i.e.,
1566                  *     pushing :B where no source is specified)
1567                  *
1568                  * (3) the destination is not under refs/tags/, and
1569                  *     if the old and new value is a commit, the new
1570                  *     is a descendant of the old.
1571                  *
1572                  * (4) it is forced using the +A:B notation, or by
1573                  *     passing the --force argument
1574                  */
1575
1576                 if (!reject_reason && !ref->deletion && !is_null_oid(&ref->old_oid)) {
1577                         if (starts_with(ref->name, "refs/tags/"))
1578                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1579                         else if (!has_object_file(&ref->old_oid))
1580                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1581                         else if (!lookup_commit_reference_gently(ref->old_oid.hash, 1) ||
1582                                  !lookup_commit_reference_gently(ref->new_oid.hash, 1))
1583                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1584                         else if (!ref_newer(&ref->new_oid, &ref->old_oid))
1585                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1586                 }
1587
1588                 /*
1589                  * "--force" will defeat any rejection implemented
1590                  * by the rules above.
1591                  */
1592                 if (!force_ref_update)
1593                         ref->status = reject_reason;
1594                 else if (reject_reason)
1595                         ref->forced_update = 1;
1596         }
1597 }
1598
1599 static void set_merge(struct branch *ret)
1600 {
1601         struct remote *remote;
1602         char *ref;
1603         struct object_id oid;
1604         int i;
1605
1606         if (!ret)
1607                 return; /* no branch */
1608         if (ret->merge)
1609                 return; /* already run */
1610         if (!ret->remote_name || !ret->merge_nr) {
1611                 /*
1612                  * no merge config; let's make sure we don't confuse callers
1613                  * with a non-zero merge_nr but a NULL merge
1614                  */
1615                 ret->merge_nr = 0;
1616                 return;
1617         }
1618
1619         remote = remote_get(ret->remote_name);
1620
1621         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1622         for (i = 0; i < ret->merge_nr; i++) {
1623                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1624                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1625                 if (!remote_find_tracking(remote, ret->merge[i]) ||
1626                     strcmp(ret->remote_name, "."))
1627                         continue;
1628                 if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
1629                              oid.hash, &ref) == 1)
1630                         ret->merge[i]->dst = ref;
1631                 else
1632                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1633         }
1634 }
1635
1636 struct branch *branch_get(const char *name)
1637 {
1638         struct branch *ret;
1639
1640         read_config();
1641         if (!name || !*name || !strcmp(name, "HEAD"))
1642                 ret = current_branch;
1643         else
1644                 ret = make_branch(name, 0);
1645         set_merge(ret);
1646         return ret;
1647 }
1648
1649 int branch_has_merge_config(struct branch *branch)
1650 {
1651         return branch && !!branch->merge;
1652 }
1653
1654 int branch_merge_matches(struct branch *branch,
1655                                  int i,
1656                                  const char *refname)
1657 {
1658         if (!branch || i < 0 || i >= branch->merge_nr)
1659                 return 0;
1660         return refname_match(branch->merge[i]->src, refname);
1661 }
1662
1663 __attribute((format (printf,2,3)))
1664 static const char *error_buf(struct strbuf *err, const char *fmt, ...)
1665 {
1666         if (err) {
1667                 va_list ap;
1668                 va_start(ap, fmt);
1669                 strbuf_vaddf(err, fmt, ap);
1670                 va_end(ap);
1671         }
1672         return NULL;
1673 }
1674
1675 const char *branch_get_upstream(struct branch *branch, struct strbuf *err)
1676 {
1677         if (!branch)
1678                 return error_buf(err, _("HEAD does not point to a branch"));
1679
1680         if (!branch->merge || !branch->merge[0]) {
1681                 /*
1682                  * no merge config; is it because the user didn't define any,
1683                  * or because it is not a real branch, and get_branch
1684                  * auto-vivified it?
1685                  */
1686                 if (!ref_exists(branch->refname))
1687                         return error_buf(err, _("no such branch: '%s'"),
1688                                          branch->name);
1689                 return error_buf(err,
1690                                  _("no upstream configured for branch '%s'"),
1691                                  branch->name);
1692         }
1693
1694         if (!branch->merge[0]->dst)
1695                 return error_buf(err,
1696                                  _("upstream branch '%s' not stored as a remote-tracking branch"),
1697                                  branch->merge[0]->src);
1698
1699         return branch->merge[0]->dst;
1700 }
1701
1702 static const char *tracking_for_push_dest(struct remote *remote,
1703                                           const char *refname,
1704                                           struct strbuf *err)
1705 {
1706         char *ret;
1707
1708         ret = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
1709         if (!ret)
1710                 return error_buf(err,
1711                                  _("push destination '%s' on remote '%s' has no local tracking branch"),
1712                                  refname, remote->name);
1713         return ret;
1714 }
1715
1716 static const char *branch_get_push_1(struct branch *branch, struct strbuf *err)
1717 {
1718         struct remote *remote;
1719
1720         if (!branch)
1721                 return error_buf(err, _("HEAD does not point to a branch"));
1722
1723         remote = remote_get(pushremote_for_branch(branch, NULL));
1724         if (!remote)
1725                 return error_buf(err,
1726                                  _("branch '%s' has no remote for pushing"),
1727                                  branch->name);
1728
1729         if (remote->push_refspec_nr) {
1730                 char *dst;
1731                 const char *ret;
1732
1733                 dst = apply_refspecs(remote->push, remote->push_refspec_nr,
1734                                      branch->refname);
1735                 if (!dst)
1736                         return error_buf(err,
1737                                          _("push refspecs for '%s' do not include '%s'"),
1738                                          remote->name, branch->name);
1739
1740                 ret = tracking_for_push_dest(remote, dst, err);
1741                 free(dst);
1742                 return ret;
1743         }
1744
1745         if (remote->mirror)
1746                 return tracking_for_push_dest(remote, branch->refname, err);
1747
1748         switch (push_default) {
1749         case PUSH_DEFAULT_NOTHING:
1750                 return error_buf(err, _("push has no destination (push.default is 'nothing')"));
1751
1752         case PUSH_DEFAULT_MATCHING:
1753         case PUSH_DEFAULT_CURRENT:
1754                 return tracking_for_push_dest(remote, branch->refname, err);
1755
1756         case PUSH_DEFAULT_UPSTREAM:
1757                 return branch_get_upstream(branch, err);
1758
1759         case PUSH_DEFAULT_UNSPECIFIED:
1760         case PUSH_DEFAULT_SIMPLE:
1761                 {
1762                         const char *up, *cur;
1763
1764                         up = branch_get_upstream(branch, err);
1765                         if (!up)
1766                                 return NULL;
1767                         cur = tracking_for_push_dest(remote, branch->refname, err);
1768                         if (!cur)
1769                                 return NULL;
1770                         if (strcmp(cur, up))
1771                                 return error_buf(err,
1772                                                  _("cannot resolve 'simple' push to a single destination"));
1773                         return cur;
1774                 }
1775         }
1776
1777         die("BUG: unhandled push situation");
1778 }
1779
1780 const char *branch_get_push(struct branch *branch, struct strbuf *err)
1781 {
1782         if (!branch->push_tracking_ref)
1783                 branch->push_tracking_ref = branch_get_push_1(branch, err);
1784         return branch->push_tracking_ref;
1785 }
1786
1787 static int ignore_symref_update(const char *refname)
1788 {
1789         struct object_id oid;
1790         int flag;
1791
1792         if (!resolve_ref_unsafe(refname, 0, oid.hash, &flag))
1793                 return 0; /* non-existing refs are OK */
1794         return (flag & REF_ISSYMREF);
1795 }
1796
1797 /*
1798  * Create and return a list of (struct ref) consisting of copies of
1799  * each remote_ref that matches refspec.  refspec must be a pattern.
1800  * Fill in the copies' peer_ref to describe the local tracking refs to
1801  * which they map.  Omit any references that would map to an existing
1802  * local symbolic ref.
1803  */
1804 static struct ref *get_expanded_map(const struct ref *remote_refs,
1805                                     const struct refspec *refspec)
1806 {
1807         const struct ref *ref;
1808         struct ref *ret = NULL;
1809         struct ref **tail = &ret;
1810
1811         for (ref = remote_refs; ref; ref = ref->next) {
1812                 char *expn_name = NULL;
1813
1814                 if (strchr(ref->name, '^'))
1815                         continue; /* a dereference item */
1816                 if (match_name_with_pattern(refspec->src, ref->name,
1817                                             refspec->dst, &expn_name) &&
1818                     !ignore_symref_update(expn_name)) {
1819                         struct ref *cpy = copy_ref(ref);
1820
1821                         cpy->peer_ref = alloc_ref(expn_name);
1822                         if (refspec->force)
1823                                 cpy->peer_ref->force = 1;
1824                         *tail = cpy;
1825                         tail = &cpy->next;
1826                 }
1827                 free(expn_name);
1828         }
1829
1830         return ret;
1831 }
1832
1833 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1834 {
1835         const struct ref *ref;
1836         for (ref = refs; ref; ref = ref->next) {
1837                 if (refname_match(name, ref->name))
1838                         return ref;
1839         }
1840         return NULL;
1841 }
1842
1843 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1844 {
1845         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1846
1847         if (!ref)
1848                 return NULL;
1849
1850         return copy_ref(ref);
1851 }
1852
1853 static struct ref *get_local_ref(const char *name)
1854 {
1855         if (!name || name[0] == '\0')
1856                 return NULL;
1857
1858         if (starts_with(name, "refs/"))
1859                 return alloc_ref(name);
1860
1861         if (starts_with(name, "heads/") ||
1862             starts_with(name, "tags/") ||
1863             starts_with(name, "remotes/"))
1864                 return alloc_ref_with_prefix("refs/", 5, name);
1865
1866         return alloc_ref_with_prefix("refs/heads/", 11, name);
1867 }
1868
1869 int get_fetch_map(const struct ref *remote_refs,
1870                   const struct refspec *refspec,
1871                   struct ref ***tail,
1872                   int missing_ok)
1873 {
1874         struct ref *ref_map, **rmp;
1875
1876         if (refspec->pattern) {
1877                 ref_map = get_expanded_map(remote_refs, refspec);
1878         } else {
1879                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1880
1881                 if (refspec->exact_sha1) {
1882                         ref_map = alloc_ref(name);
1883                         get_oid_hex(name, &ref_map->old_oid);
1884                 } else {
1885                         ref_map = get_remote_ref(remote_refs, name);
1886                 }
1887                 if (!missing_ok && !ref_map)
1888                         die("Couldn't find remote ref %s", name);
1889                 if (ref_map) {
1890                         ref_map->peer_ref = get_local_ref(refspec->dst);
1891                         if (ref_map->peer_ref && refspec->force)
1892                                 ref_map->peer_ref->force = 1;
1893                 }
1894         }
1895
1896         for (rmp = &ref_map; *rmp; ) {
1897                 if ((*rmp)->peer_ref) {
1898                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1899                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1900                                 struct ref *ignore = *rmp;
1901                                 error("* Ignoring funny ref '%s' locally",
1902                                       (*rmp)->peer_ref->name);
1903                                 *rmp = (*rmp)->next;
1904                                 free(ignore->peer_ref);
1905                                 free(ignore);
1906                                 continue;
1907                         }
1908                 }
1909                 rmp = &((*rmp)->next);
1910         }
1911
1912         if (ref_map)
1913                 tail_link_ref(ref_map, tail);
1914
1915         return 0;
1916 }
1917
1918 int resolve_remote_symref(struct ref *ref, struct ref *list)
1919 {
1920         if (!ref->symref)
1921                 return 0;
1922         for (; list; list = list->next)
1923                 if (!strcmp(ref->symref, list->name)) {
1924                         oidcpy(&ref->old_oid, &list->old_oid);
1925                         return 0;
1926                 }
1927         return 1;
1928 }
1929
1930 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1931 {
1932         while (list) {
1933                 struct commit *commit = pop_commit(&list);
1934                 commit->object.flags &= ~mark;
1935         }
1936 }
1937
1938 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
1939 {
1940         struct object *o;
1941         struct commit *old, *new;
1942         struct commit_list *list, *used;
1943         int found = 0;
1944
1945         /*
1946          * Both new and old must be commit-ish and new is descendant of
1947          * old.  Otherwise we require --force.
1948          */
1949         o = deref_tag(parse_object(old_oid->hash), NULL, 0);
1950         if (!o || o->type != OBJ_COMMIT)
1951                 return 0;
1952         old = (struct commit *) o;
1953
1954         o = deref_tag(parse_object(new_oid->hash), NULL, 0);
1955         if (!o || o->type != OBJ_COMMIT)
1956                 return 0;
1957         new = (struct commit *) o;
1958
1959         if (parse_commit(new) < 0)
1960                 return 0;
1961
1962         used = list = NULL;
1963         commit_list_insert(new, &list);
1964         while (list) {
1965                 new = pop_most_recent_commit(&list, TMP_MARK);
1966                 commit_list_insert(new, &used);
1967                 if (new == old) {
1968                         found = 1;
1969                         break;
1970                 }
1971         }
1972         unmark_and_free(list, TMP_MARK);
1973         unmark_and_free(used, TMP_MARK);
1974         return found;
1975 }
1976
1977 /*
1978  * Compare a branch with its upstream, and save their differences (number
1979  * of commits) in *num_ours and *num_theirs. The name of the upstream branch
1980  * (or NULL if no upstream is defined) is returned via *upstream_name, if it
1981  * is not itself NULL.
1982  *
1983  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
1984  * upstream defined, or ref does not exist), 0 otherwise.
1985  */
1986 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
1987                        const char **upstream_name)
1988 {
1989         struct object_id oid;
1990         struct commit *ours, *theirs;
1991         struct rev_info revs;
1992         const char *base;
1993         struct argv_array argv = ARGV_ARRAY_INIT;
1994
1995         /* Cannot stat unless we are marked to build on top of somebody else. */
1996         base = branch_get_upstream(branch, NULL);
1997         if (upstream_name)
1998                 *upstream_name = base;
1999         if (!base)
2000                 return -1;
2001
2002         /* Cannot stat if what we used to build on no longer exists */
2003         if (read_ref(base, oid.hash))
2004                 return -1;
2005         theirs = lookup_commit_reference(oid.hash);
2006         if (!theirs)
2007                 return -1;
2008
2009         if (read_ref(branch->refname, oid.hash))
2010                 return -1;
2011         ours = lookup_commit_reference(oid.hash);
2012         if (!ours)
2013                 return -1;
2014
2015         /* are we the same? */
2016         if (theirs == ours) {
2017                 *num_theirs = *num_ours = 0;
2018                 return 0;
2019         }
2020
2021         /* Run "rev-list --left-right ours...theirs" internally... */
2022         argv_array_push(&argv, ""); /* ignored */
2023         argv_array_push(&argv, "--left-right");
2024         argv_array_pushf(&argv, "%s...%s",
2025                          oid_to_hex(&ours->object.oid),
2026                          oid_to_hex(&theirs->object.oid));
2027         argv_array_push(&argv, "--");
2028
2029         init_revisions(&revs, NULL);
2030         setup_revisions(argv.argc, argv.argv, &revs, NULL);
2031         if (prepare_revision_walk(&revs))
2032                 die("revision walk setup failed");
2033
2034         /* ... and count the commits on each side. */
2035         *num_ours = 0;
2036         *num_theirs = 0;
2037         while (1) {
2038                 struct commit *c = get_revision(&revs);
2039                 if (!c)
2040                         break;
2041                 if (c->object.flags & SYMMETRIC_LEFT)
2042                         (*num_ours)++;
2043                 else
2044                         (*num_theirs)++;
2045         }
2046
2047         /* clear object flags smudged by the above traversal */
2048         clear_commit_marks(ours, ALL_REV_FLAGS);
2049         clear_commit_marks(theirs, ALL_REV_FLAGS);
2050
2051         argv_array_clear(&argv);
2052         return 0;
2053 }
2054
2055 /*
2056  * Return true when there is anything to report, otherwise false.
2057  */
2058 int format_tracking_info(struct branch *branch, struct strbuf *sb)
2059 {
2060         int ours, theirs;
2061         const char *full_base;
2062         char *base;
2063         int upstream_is_gone = 0;
2064
2065         if (stat_tracking_info(branch, &ours, &theirs, &full_base) < 0) {
2066                 if (!full_base)
2067                         return 0;
2068                 upstream_is_gone = 1;
2069         }
2070
2071         base = shorten_unambiguous_ref(full_base, 0);
2072         if (upstream_is_gone) {
2073                 strbuf_addf(sb,
2074                         _("Your branch is based on '%s', but the upstream is gone.\n"),
2075                         base);
2076                 if (advice_status_hints)
2077                         strbuf_addf(sb,
2078                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
2079         } else if (!ours && !theirs) {
2080                 strbuf_addf(sb,
2081                         _("Your branch is up-to-date with '%s'.\n"),
2082                         base);
2083         } else if (!theirs) {
2084                 strbuf_addf(sb,
2085                         Q_("Your branch is ahead of '%s' by %d commit.\n",
2086                            "Your branch is ahead of '%s' by %d commits.\n",
2087                            ours),
2088                         base, ours);
2089                 if (advice_status_hints)
2090                         strbuf_addf(sb,
2091                                 _("  (use \"git push\" to publish your local commits)\n"));
2092         } else if (!ours) {
2093                 strbuf_addf(sb,
2094                         Q_("Your branch is behind '%s' by %d commit, "
2095                                "and can be fast-forwarded.\n",
2096                            "Your branch is behind '%s' by %d commits, "
2097                                "and can be fast-forwarded.\n",
2098                            theirs),
2099                         base, theirs);
2100                 if (advice_status_hints)
2101                         strbuf_addf(sb,
2102                                 _("  (use \"git pull\" to update your local branch)\n"));
2103         } else {
2104                 strbuf_addf(sb,
2105                         Q_("Your branch and '%s' have diverged,\n"
2106                                "and have %d and %d different commit each, "
2107                                "respectively.\n",
2108                            "Your branch and '%s' have diverged,\n"
2109                                "and have %d and %d different commits each, "
2110                                "respectively.\n",
2111                            theirs),
2112                         base, ours, theirs);
2113                 if (advice_status_hints)
2114                         strbuf_addf(sb,
2115                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
2116         }
2117         free(base);
2118         return 1;
2119 }
2120
2121 static int one_local_ref(const char *refname, const struct object_id *oid,
2122                          int flag, void *cb_data)
2123 {
2124         struct ref ***local_tail = cb_data;
2125         struct ref *ref;
2126
2127         /* we already know it starts with refs/ to get here */
2128         if (check_refname_format(refname + 5, 0))
2129                 return 0;
2130
2131         ref = alloc_ref(refname);
2132         oidcpy(&ref->new_oid, oid);
2133         **local_tail = ref;
2134         *local_tail = &ref->next;
2135         return 0;
2136 }
2137
2138 struct ref *get_local_heads(void)
2139 {
2140         struct ref *local_refs = NULL, **local_tail = &local_refs;
2141
2142         for_each_ref(one_local_ref, &local_tail);
2143         return local_refs;
2144 }
2145
2146 struct ref *guess_remote_head(const struct ref *head,
2147                               const struct ref *refs,
2148                               int all)
2149 {
2150         const struct ref *r;
2151         struct ref *list = NULL;
2152         struct ref **tail = &list;
2153
2154         if (!head)
2155                 return NULL;
2156
2157         /*
2158          * Some transports support directly peeking at
2159          * where HEAD points; if that is the case, then
2160          * we don't have to guess.
2161          */
2162         if (head->symref)
2163                 return copy_ref(find_ref_by_name(refs, head->symref));
2164
2165         /* If refs/heads/master could be right, it is. */
2166         if (!all) {
2167                 r = find_ref_by_name(refs, "refs/heads/master");
2168                 if (r && !oidcmp(&r->old_oid, &head->old_oid))
2169                         return copy_ref(r);
2170         }
2171
2172         /* Look for another ref that points there */
2173         for (r = refs; r; r = r->next) {
2174                 if (r != head &&
2175                     starts_with(r->name, "refs/heads/") &&
2176                     !oidcmp(&r->old_oid, &head->old_oid)) {
2177                         *tail = copy_ref(r);
2178                         tail = &((*tail)->next);
2179                         if (!all)
2180                                 break;
2181                 }
2182         }
2183
2184         return list;
2185 }
2186
2187 struct stale_heads_info {
2188         struct string_list *ref_names;
2189         struct ref **stale_refs_tail;
2190         struct refspec *refs;
2191         int ref_count;
2192 };
2193
2194 static int get_stale_heads_cb(const char *refname, const struct object_id *oid,
2195                               int flags, void *cb_data)
2196 {
2197         struct stale_heads_info *info = cb_data;
2198         struct string_list matches = STRING_LIST_INIT_DUP;
2199         struct refspec query;
2200         int i, stale = 1;
2201         memset(&query, 0, sizeof(struct refspec));
2202         query.dst = (char *)refname;
2203
2204         query_refspecs_multiple(info->refs, info->ref_count, &query, &matches);
2205         if (matches.nr == 0)
2206                 goto clean_exit; /* No matches */
2207
2208         /*
2209          * If we did find a suitable refspec and it's not a symref and
2210          * it's not in the list of refs that currently exist in that
2211          * remote, we consider it to be stale. In order to deal with
2212          * overlapping refspecs, we need to go over all of the
2213          * matching refs.
2214          */
2215         if (flags & REF_ISSYMREF)
2216                 goto clean_exit;
2217
2218         for (i = 0; stale && i < matches.nr; i++)
2219                 if (string_list_has_string(info->ref_names, matches.items[i].string))
2220                         stale = 0;
2221
2222         if (stale) {
2223                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2224                 oidcpy(&ref->new_oid, oid);
2225         }
2226
2227 clean_exit:
2228         string_list_clear(&matches, 0);
2229         return 0;
2230 }
2231
2232 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
2233 {
2234         struct ref *ref, *stale_refs = NULL;
2235         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2236         struct stale_heads_info info;
2237
2238         info.ref_names = &ref_names;
2239         info.stale_refs_tail = &stale_refs;
2240         info.refs = refs;
2241         info.ref_count = ref_count;
2242         for (ref = fetch_map; ref; ref = ref->next)
2243                 string_list_append(&ref_names, ref->name);
2244         string_list_sort(&ref_names);
2245         for_each_ref(get_stale_heads_cb, &info);
2246         string_list_clear(&ref_names, 0);
2247         return stale_refs;
2248 }
2249
2250 /*
2251  * Compare-and-swap
2252  */
2253 static void clear_cas_option(struct push_cas_option *cas)
2254 {
2255         int i;
2256
2257         for (i = 0; i < cas->nr; i++)
2258                 free(cas->entry[i].refname);
2259         free(cas->entry);
2260         memset(cas, 0, sizeof(*cas));
2261 }
2262
2263 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2264                                       const char *refname,
2265                                       size_t refnamelen)
2266 {
2267         struct push_cas *entry;
2268         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2269         entry = &cas->entry[cas->nr++];
2270         memset(entry, 0, sizeof(*entry));
2271         entry->refname = xmemdupz(refname, refnamelen);
2272         return entry;
2273 }
2274
2275 int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2276 {
2277         const char *colon;
2278         struct push_cas *entry;
2279
2280         if (unset) {
2281                 /* "--no-<option>" */
2282                 clear_cas_option(cas);
2283                 return 0;
2284         }
2285
2286         if (!arg) {
2287                 /* just "--<option>" */
2288                 cas->use_tracking_for_rest = 1;
2289                 return 0;
2290         }
2291
2292         /* "--<option>=refname" or "--<option>=refname:value" */
2293         colon = strchrnul(arg, ':');
2294         entry = add_cas_entry(cas, arg, colon - arg);
2295         if (!*colon)
2296                 entry->use_tracking = 1;
2297         else if (get_sha1(colon + 1, entry->expect))
2298                 return error("cannot parse expected object name '%s'", colon + 1);
2299         return 0;
2300 }
2301
2302 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2303 {
2304         return parse_push_cas_option(opt->value, arg, unset);
2305 }
2306
2307 int is_empty_cas(const struct push_cas_option *cas)
2308 {
2309         return !cas->use_tracking_for_rest && !cas->nr;
2310 }
2311
2312 /*
2313  * Look at remote.fetch refspec and see if we have a remote
2314  * tracking branch for the refname there.  Fill its current
2315  * value in sha1[].
2316  * If we cannot do so, return negative to signal an error.
2317  */
2318 static int remote_tracking(struct remote *remote, const char *refname,
2319                            struct object_id *oid)
2320 {
2321         char *dst;
2322
2323         dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
2324         if (!dst)
2325                 return -1; /* no tracking ref for refname at remote */
2326         if (read_ref(dst, oid->hash))
2327                 return -1; /* we know what the tracking ref is but we cannot read it */
2328         return 0;
2329 }
2330
2331 static void apply_cas(struct push_cas_option *cas,
2332                       struct remote *remote,
2333                       struct ref *ref)
2334 {
2335         int i;
2336
2337         /* Find an explicit --<option>=<name>[:<value>] entry */
2338         for (i = 0; i < cas->nr; i++) {
2339                 struct push_cas *entry = &cas->entry[i];
2340                 if (!refname_match(entry->refname, ref->name))
2341                         continue;
2342                 ref->expect_old_sha1 = 1;
2343                 if (!entry->use_tracking)
2344                         hashcpy(ref->old_oid_expect.hash, cas->entry[i].expect);
2345                 else if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2346                         ref->expect_old_no_trackback = 1;
2347                 return;
2348         }
2349
2350         /* Are we using "--<option>" to cover all? */
2351         if (!cas->use_tracking_for_rest)
2352                 return;
2353
2354         ref->expect_old_sha1 = 1;
2355         if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2356                 ref->expect_old_no_trackback = 1;
2357 }
2358
2359 void apply_push_cas(struct push_cas_option *cas,
2360                     struct remote *remote,
2361                     struct ref *remote_refs)
2362 {
2363         struct ref *ref;
2364         for (ref = remote_refs; ref; ref = ref->next)
2365                 apply_cas(cas, remote, ref);
2366 }