git.oblomov.eu Git - git/blob - remote.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "remote.h"
   4 #include "refs.h"
   5 #include "refspec.h"
   6 #include "object-store.h"
   7 #include "commit.h"
   8 #include "diff.h"
   9 #include "revision.h"
  10 #include "dir.h"
  11 #include "tag.h"
  12 #include "string-list.h"
  13 #include "mergesort.h"
  14 #include "argv-array.h"
  15
  16 enum map_direction { FROM_SRC, FROM_DST };
  17
  18 struct counted_string {
  19         size_t len;
  20         const char *s;
  21 };
  22 struct rewrite {
  23         const char *base;
  24         size_t baselen;
  25         struct counted_string *instead_of;
  26         int instead_of_nr;
  27         int instead_of_alloc;
  28 };
  29 struct rewrites {
  30         struct rewrite **rewrite;
  31         int rewrite_alloc;
  32         int rewrite_nr;
  33 };
  34
  35 static struct remote **remotes;
  36 static int remotes_alloc;
  37 static int remotes_nr;
  38 static struct hashmap remotes_hash;
  39
  40 static struct branch **branches;
  41 static int branches_alloc;
  42 static int branches_nr;
  43
  44 static struct branch *current_branch;
  45 static const char *pushremote_name;
  46
  47 static struct rewrites rewrites;
  48 static struct rewrites rewrites_push;
  49
  50 static int valid_remote(const struct remote *remote)
  51 {
  52         return (!!remote->url) || (!!remote->foreign_vcs);
  53 }
  54
  55 static const char *alias_url(const char *url, struct rewrites *r)
  56 {
  57         int i, j;
  58         struct counted_string *longest;
  59         int longest_i;
  60
  61         longest = NULL;
  62         longest_i = -1;
  63         for (i = 0; i < r->rewrite_nr; i++) {
  64                 if (!r->rewrite[i])
  65                         continue;
  66                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  67                         if (starts_with(url, r->rewrite[i]->instead_of[j].s) &&
  68                             (!longest ||
  69                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  70                                 longest = &(r->rewrite[i]->instead_of[j]);
  71                                 longest_i = i;
  72                         }
  73                 }
  74         }
  75         if (!longest)
  76                 return url;
  77
  78         return xstrfmt("%s%s", r->rewrite[longest_i]->base, url + longest->len);
  79 }
  80
  81 static void add_url(struct remote *remote, const char *url)
  82 {
  83         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
  84         remote->url[remote->url_nr++] = url;
  85 }
  86
  87 static void add_pushurl(struct remote *remote, const char *pushurl)
  88 {
  89         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
  90         remote->pushurl[remote->pushurl_nr++] = pushurl;
  91 }
  92
  93 static void add_pushurl_alias(struct remote *remote, const char *url)
  94 {
  95         const char *pushurl = alias_url(url, &rewrites_push);
  96         if (pushurl != url)
  97                 add_pushurl(remote, pushurl);
  98 }
  99
 100 static void add_url_alias(struct remote *remote, const char *url)
 101 {
 102         add_url(remote, alias_url(url, &rewrites));
 103         add_pushurl_alias(remote, url);
 104 }
 105
 106 struct remotes_hash_key {
 107         const char *str;
 108         int len;
 109 };
 110
 111 static int remotes_hash_cmp(const void *unused_cmp_data,
 112                             const void *entry,
 113                             const void *entry_or_key,
 114                             const void *keydata)
 115 {
 116         const struct remote *a = entry;
 117         const struct remote *b = entry_or_key;
 118         const struct remotes_hash_key *key = keydata;
 119
 120         if (key)
 121                 return strncmp(a->name, key->str, key->len) || a->name[key->len];
 122         else
 123                 return strcmp(a->name, b->name);
 124 }
 125
 126 static inline void init_remotes_hash(void)
 127 {
 128         if (!remotes_hash.cmpfn)
 129                 hashmap_init(&remotes_hash, remotes_hash_cmp, NULL, 0);
 130 }
 131
 132 static struct remote *make_remote(const char *name, int len)
 133 {
 134         struct remote *ret, *replaced;
 135         struct remotes_hash_key lookup;
 136         struct hashmap_entry lookup_entry;
 137
 138         if (!len)
 139                 len = strlen(name);
 140
 141         init_remotes_hash();
 142         lookup.str = name;
 143         lookup.len = len;
 144         hashmap_entry_init(&lookup_entry, memhash(name, len));
 145
 146         if ((ret = hashmap_get(&remotes_hash, &lookup_entry, &lookup)) != NULL)
 147                 return ret;
 148
 149         ret = xcalloc(1, sizeof(struct remote));
 150         ret->prune = -1;  /* unspecified */
 151         ret->prune_tags = -1;  /* unspecified */
 152         ret->name = xstrndup(name, len);
 153         refspec_init(&ret->push, REFSPEC_PUSH);
 154         refspec_init(&ret->fetch, REFSPEC_FETCH);
 155
 156         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 157         remotes[remotes_nr++] = ret;
 158
 159         hashmap_entry_init(ret, lookup_entry.hash);
 160         replaced = hashmap_put(&remotes_hash, ret);
 161         assert(replaced == NULL);  /* no previous entry overwritten */
 162         return ret;
 163 }
 164
 165 static void add_merge(struct branch *branch, const char *name)
 166 {
 167         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 168                    branch->merge_alloc);
 169         branch->merge_name[branch->merge_nr++] = name;
 170 }
 171
 172 static struct branch *make_branch(const char *name, int len)
 173 {
 174         struct branch *ret;
 175         int i;
 176
 177         for (i = 0; i < branches_nr; i++) {
 178                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 179                            !branches[i]->name[len]) :
 180                     !strcmp(name, branches[i]->name))
 181                         return branches[i];
 182         }
 183
 184         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 185         ret = xcalloc(1, sizeof(struct branch));
 186         branches[branches_nr++] = ret;
 187         if (len)
 188                 ret->name = xstrndup(name, len);
 189         else
 190                 ret->name = xstrdup(name);
 191         ret->refname = xstrfmt("refs/heads/%s", ret->name);
 192
 193         return ret;
 194 }
 195
 196 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 197 {
 198         struct rewrite *ret;
 199         int i;
 200
 201         for (i = 0; i < r->rewrite_nr; i++) {
 202                 if (len
 203                     ? (len == r->rewrite[i]->baselen &&
 204                        !strncmp(base, r->rewrite[i]->base, len))
 205                     : !strcmp(base, r->rewrite[i]->base))
 206                         return r->rewrite[i];
 207         }
 208
 209         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 210         ret = xcalloc(1, sizeof(struct rewrite));
 211         r->rewrite[r->rewrite_nr++] = ret;
 212         if (len) {
 213                 ret->base = xstrndup(base, len);
 214                 ret->baselen = len;
 215         }
 216         else {
 217                 ret->base = xstrdup(base);
 218                 ret->baselen = strlen(base);
 219         }
 220         return ret;
 221 }
 222
 223 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 224 {
 225         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 226         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 227         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 228         rewrite->instead_of_nr++;
 229 }
 230
 231 static const char *skip_spaces(const char *s)
 232 {
 233         while (isspace(*s))
 234                 s++;
 235         return s;
 236 }
 237
 238 static void read_remotes_file(struct remote *remote)
 239 {
 240         struct strbuf buf = STRBUF_INIT;
 241         FILE *f = fopen_or_warn(git_path("remotes/%s", remote->name), "r");
 242
 243         if (!f)
 244                 return;
 245         remote->configured_in_repo = 1;
 246         remote->origin = REMOTE_REMOTES;
 247         while (strbuf_getline(&buf, f) != EOF) {
 248                 const char *v;
 249
 250                 strbuf_rtrim(&buf);
 251
 252                 if (skip_prefix(buf.buf, "URL:", &v))
 253                         add_url_alias(remote, xstrdup(skip_spaces(v)));
 254                 else if (skip_prefix(buf.buf, "Push:", &v))
 255                         refspec_append(&remote->push, skip_spaces(v));
 256                 else if (skip_prefix(buf.buf, "Pull:", &v))
 257                         refspec_append(&remote->fetch, skip_spaces(v));
 258         }
 259         strbuf_release(&buf);
 260         fclose(f);
 261 }
 262
 263 static void read_branches_file(struct remote *remote)
 264 {
 265         char *frag;
 266         struct strbuf buf = STRBUF_INIT;
 267         FILE *f = fopen_or_warn(git_path("branches/%s", remote->name), "r");
 268
 269         if (!f)
 270                 return;
 271
 272         strbuf_getline_lf(&buf, f);
 273         fclose(f);
 274         strbuf_trim(&buf);
 275         if (!buf.len) {
 276                 strbuf_release(&buf);
 277                 return;
 278         }
 279
 280         remote->configured_in_repo = 1;
 281         remote->origin = REMOTE_BRANCHES;
 282
 283         /*
 284          * The branches file would have URL and optionally
 285          * #branch specified.  The "master" (or specified) branch is
 286          * fetched and stored in the local branch matching the
 287          * remote name.
 288          */
 289         frag = strchr(buf.buf, '#');
 290         if (frag)
 291                 *(frag++) = '\0';
 292         else
 293                 frag = "master";
 294
 295         add_url_alias(remote, strbuf_detach(&buf, NULL));
 296         strbuf_addf(&buf, "refs/heads/%s:refs/heads/%s",
 297                     frag, remote->name);
 298         refspec_append(&remote->fetch, buf.buf);
 299
 300         /*
 301          * Cogito compatible push: push current HEAD to remote #branch
 302          * (master if missing)
 303          */
 304         strbuf_reset(&buf);
 305         strbuf_addf(&buf, "HEAD:refs/heads/%s", frag);
 306         refspec_append(&remote->push, buf.buf);
 307         remote->fetch_tags = 1; /* always auto-follow */
 308         strbuf_release(&buf);
 309 }
 310
 311 static int handle_config(const char *key, const char *value, void *cb)
 312 {
 313         const char *name;
 314         int namelen;
 315         const char *subkey;
 316         struct remote *remote;
 317         struct branch *branch;
 318         if (parse_config_key(key, "branch", &name, &namelen, &subkey) >= 0) {
 319                 if (!name)
 320                         return 0;
 321                 branch = make_branch(name, namelen);
 322                 if (!strcmp(subkey, "remote")) {
 323                         return git_config_string(&branch->remote_name, key, value);
 324                 } else if (!strcmp(subkey, "pushremote")) {
 325                         return git_config_string(&branch->pushremote_name, key, value);
 326                 } else if (!strcmp(subkey, "merge")) {
 327                         if (!value)
 328                                 return config_error_nonbool(key);
 329                         add_merge(branch, xstrdup(value));
 330                 }
 331                 return 0;
 332         }
 333         if (parse_config_key(key, "url", &name, &namelen, &subkey) >= 0) {
 334                 struct rewrite *rewrite;
 335                 if (!name)
 336                         return 0;
 337                 if (!strcmp(subkey, "insteadof")) {
 338                         rewrite = make_rewrite(&rewrites, name, namelen);
 339                         if (!value)
 340                                 return config_error_nonbool(key);
 341                         add_instead_of(rewrite, xstrdup(value));
 342                 } else if (!strcmp(subkey, "pushinsteadof")) {
 343                         rewrite = make_rewrite(&rewrites_push, name, namelen);
 344                         if (!value)
 345                                 return config_error_nonbool(key);
 346                         add_instead_of(rewrite, xstrdup(value));
 347                 }
 348         }
 349
 350         if (parse_config_key(key, "remote", &name, &namelen, &subkey) < 0)
 351                 return 0;
 352
 353         /* Handle remote.* variables */
 354         if (!name && !strcmp(subkey, "pushdefault"))
 355                 return git_config_string(&pushremote_name, key, value);
 356
 357         if (!name)
 358                 return 0;
 359         /* Handle remote.<name>.* variables */
 360         if (*name == '/') {
 361                 warning("Config remote shorthand cannot begin with '/': %s",
 362                         name);
 363                 return 0;
 364         }
 365         remote = make_remote(name, namelen);
 366         remote->origin = REMOTE_CONFIG;
 367         if (current_config_scope() == CONFIG_SCOPE_REPO)
 368                 remote->configured_in_repo = 1;
 369         if (!strcmp(subkey, "mirror"))
 370                 remote->mirror = git_config_bool(key, value);
 371         else if (!strcmp(subkey, "skipdefaultupdate"))
 372                 remote->skip_default_update = git_config_bool(key, value);
 373         else if (!strcmp(subkey, "skipfetchall"))
 374                 remote->skip_default_update = git_config_bool(key, value);
 375         else if (!strcmp(subkey, "prune"))
 376                 remote->prune = git_config_bool(key, value);
 377         else if (!strcmp(subkey, "prunetags"))
 378                 remote->prune_tags = git_config_bool(key, value);
 379         else if (!strcmp(subkey, "url")) {
 380                 const char *v;
 381                 if (git_config_string(&v, key, value))
 382                         return -1;
 383                 add_url(remote, v);
 384         } else if (!strcmp(subkey, "pushurl")) {
 385                 const char *v;
 386                 if (git_config_string(&v, key, value))
 387                         return -1;
 388                 add_pushurl(remote, v);
 389         } else if (!strcmp(subkey, "push")) {
 390                 const char *v;
 391                 if (git_config_string(&v, key, value))
 392                         return -1;
 393                 refspec_append(&remote->push, v);
 394                 free((char *)v);
 395         } else if (!strcmp(subkey, "fetch")) {
 396                 const char *v;
 397                 if (git_config_string(&v, key, value))
 398                         return -1;
 399                 refspec_append(&remote->fetch, v);
 400                 free((char *)v);
 401         } else if (!strcmp(subkey, "receivepack")) {
 402                 const char *v;
 403                 if (git_config_string(&v, key, value))
 404                         return -1;
 405                 if (!remote->receivepack)
 406                         remote->receivepack = v;
 407                 else
 408                         error("more than one receivepack given, using the first");
 409         } else if (!strcmp(subkey, "uploadpack")) {
 410                 const char *v;
 411                 if (git_config_string(&v, key, value))
 412                         return -1;
 413                 if (!remote->uploadpack)
 414                         remote->uploadpack = v;
 415                 else
 416                         error("more than one uploadpack given, using the first");
 417         } else if (!strcmp(subkey, "tagopt")) {
 418                 if (!strcmp(value, "--no-tags"))
 419                         remote->fetch_tags = -1;
 420                 else if (!strcmp(value, "--tags"))
 421                         remote->fetch_tags = 2;
 422         } else if (!strcmp(subkey, "proxy")) {
 423                 return git_config_string((const char **)&remote->http_proxy,
 424                                          key, value);
 425         } else if (!strcmp(subkey, "proxyauthmethod")) {
 426                 return git_config_string((const char **)&remote->http_proxy_authmethod,
 427                                          key, value);
 428         } else if (!strcmp(subkey, "vcs")) {
 429                 return git_config_string(&remote->foreign_vcs, key, value);
 430         }
 431         return 0;
 432 }
 433
 434 static void alias_all_urls(void)
 435 {
 436         int i, j;
 437         for (i = 0; i < remotes_nr; i++) {
 438                 int add_pushurl_aliases;
 439                 if (!remotes[i])
 440                         continue;
 441                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 442                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 443                 }
 444                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 445                 for (j = 0; j < remotes[i]->url_nr; j++) {
 446                         if (add_pushurl_aliases)
 447                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 448                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 449                 }
 450         }
 451 }
 452
 453 static void read_config(void)
 454 {
 455         static int loaded;
 456         int flag;
 457
 458         if (loaded)
 459                 return;
 460         loaded = 1;
 461
 462         current_branch = NULL;
 463         if (startup_info->have_repository) {
 464                 const char *head_ref = resolve_ref_unsafe("HEAD", 0, NULL, &flag);
 465                 if (head_ref && (flag & REF_ISSYMREF) &&
 466                     skip_prefix(head_ref, "refs/heads/", &head_ref)) {
 467                         current_branch = make_branch(head_ref, 0);
 468                 }
 469         }
 470         git_config(handle_config, NULL);
 471         alias_all_urls();
 472 }
 473
 474 static int valid_remote_nick(const char *name)
 475 {
 476         if (!name[0] || is_dot_or_dotdot(name))
 477                 return 0;
 478
 479         /* remote nicknames cannot contain slashes */
 480         while (*name)
 481                 if (is_dir_sep(*name++))
 482                         return 0;
 483         return 1;
 484 }
 485
 486 const char *remote_for_branch(struct branch *branch, int *explicit)
 487 {
 488         if (branch && branch->remote_name) {
 489                 if (explicit)
 490                         *explicit = 1;
 491                 return branch->remote_name;
 492         }
 493         if (explicit)
 494                 *explicit = 0;
 495         return "origin";
 496 }
 497
 498 const char *pushremote_for_branch(struct branch *branch, int *explicit)
 499 {
 500         if (branch && branch->pushremote_name) {
 501                 if (explicit)
 502                         *explicit = 1;
 503                 return branch->pushremote_name;
 504         }
 505         if (pushremote_name) {
 506                 if (explicit)
 507                         *explicit = 1;
 508                 return pushremote_name;
 509         }
 510         return remote_for_branch(branch, explicit);
 511 }
 512
 513 const char *remote_ref_for_branch(struct branch *branch, int for_push,
 514                                   int *explicit)
 515 {
 516         if (branch) {
 517                 if (!for_push) {
 518                         if (branch->merge_nr) {
 519                                 if (explicit)
 520                                         *explicit = 1;
 521                                 return branch->merge_name[0];
 522                         }
 523                 } else {
 524                         const char *dst, *remote_name =
 525                                 pushremote_for_branch(branch, NULL);
 526                         struct remote *remote = remote_get(remote_name);
 527
 528                         if (remote && remote->push.nr &&
 529                             (dst = apply_refspecs(&remote->push,
 530                                                   branch->refname))) {
 531                                 if (explicit)
 532                                         *explicit = 1;
 533                                 return dst;
 534                         }
 535                 }
 536         }
 537         if (explicit)
 538                 *explicit = 0;
 539         return "";
 540 }
 541
 542 static struct remote *remote_get_1(const char *name,
 543                                    const char *(*get_default)(struct branch *, int *))
 544 {
 545         struct remote *ret;
 546         int name_given = 0;
 547
 548         read_config();
 549
 550         if (name)
 551                 name_given = 1;
 552         else
 553                 name = get_default(current_branch, &name_given);
 554
 555         ret = make_remote(name, 0);
 556         if (valid_remote_nick(name) && have_git_dir()) {
 557                 if (!valid_remote(ret))
 558                         read_remotes_file(ret);
 559                 if (!valid_remote(ret))
 560                         read_branches_file(ret);
 561         }
 562         if (name_given && !valid_remote(ret))
 563                 add_url_alias(ret, name);
 564         if (!valid_remote(ret))
 565                 return NULL;
 566         return ret;
 567 }
 568
 569 struct remote *remote_get(const char *name)
 570 {
 571         return remote_get_1(name, remote_for_branch);
 572 }
 573
 574 struct remote *pushremote_get(const char *name)
 575 {
 576         return remote_get_1(name, pushremote_for_branch);
 577 }
 578
 579 int remote_is_configured(struct remote *remote, int in_repo)
 580 {
 581         if (!remote)
 582                 return 0;
 583         if (in_repo)
 584                 return remote->configured_in_repo;
 585         return !!remote->origin;
 586 }
 587
 588 int for_each_remote(each_remote_fn fn, void *priv)
 589 {
 590         int i, result = 0;
 591         read_config();
 592         for (i = 0; i < remotes_nr && !result; i++) {
 593                 struct remote *r = remotes[i];
 594                 if (!r)
 595                         continue;
 596                 result = fn(r, priv);
 597         }
 598         return result;
 599 }
 600
 601 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
 602 {
 603         if (strcmp(ref1->name, ref2->name)) {
 604                 if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 605                     ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
 606                         die(_("Cannot fetch both %s and %s to %s"),
 607                             ref1->name, ref2->name, ref2->peer_ref->name);
 608                 } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 609                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 610                         warning(_("%s usually tracks %s, not %s"),
 611                                 ref2->peer_ref->name, ref2->name, ref1->name);
 612                 } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
 613                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 614                         die(_("%s tracks both %s and %s"),
 615                             ref2->peer_ref->name, ref1->name, ref2->name);
 616                 } else {
 617                         /*
 618                          * This last possibility doesn't occur because
 619                          * FETCH_HEAD_IGNORE entries always appear at
 620                          * the end of the list.
 621                          */
 622                         die(_("Internal error"));
 623                 }
 624         }
 625         free(ref2->peer_ref);
 626         free(ref2);
 627 }
 628
 629 struct ref *ref_remove_duplicates(struct ref *ref_map)
 630 {
 631         struct string_list refs = STRING_LIST_INIT_NODUP;
 632         struct ref *retval = NULL;
 633         struct ref **p = &retval;
 634
 635         while (ref_map) {
 636                 struct ref *ref = ref_map;
 637
 638                 ref_map = ref_map->next;
 639                 ref->next = NULL;
 640
 641                 if (!ref->peer_ref) {
 642                         *p = ref;
 643                         p = &ref->next;
 644                 } else {
 645                         struct string_list_item *item =
 646                                 string_list_insert(&refs, ref->peer_ref->name);
 647
 648                         if (item->util) {
 649                                 /* Entry already existed */
 650                                 handle_duplicate((struct ref *)item->util, ref);
 651                         } else {
 652                                 *p = ref;
 653                                 p = &ref->next;
 654                                 item->util = ref;
 655                         }
 656                 }
 657         }
 658
 659         string_list_clear(&refs, 0);
 660         return retval;
 661 }
 662
 663 int remote_has_url(struct remote *remote, const char *url)
 664 {
 665         int i;
 666         for (i = 0; i < remote->url_nr; i++) {
 667                 if (!strcmp(remote->url[i], url))
 668                         return 1;
 669         }
 670         return 0;
 671 }
 672
 673 static int match_name_with_pattern(const char *key, const char *name,
 674                                    const char *value, char **result)
 675 {
 676         const char *kstar = strchr(key, '*');
 677         size_t klen;
 678         size_t ksuffixlen;
 679         size_t namelen;
 680         int ret;
 681         if (!kstar)
 682                 die("Key '%s' of pattern had no '*'", key);
 683         klen = kstar - key;
 684         ksuffixlen = strlen(kstar + 1);
 685         namelen = strlen(name);
 686         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 687                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 688         if (ret && value) {
 689                 struct strbuf sb = STRBUF_INIT;
 690                 const char *vstar = strchr(value, '*');
 691                 if (!vstar)
 692                         die("Value '%s' of pattern has no '*'", value);
 693                 strbuf_add(&sb, value, vstar - value);
 694                 strbuf_add(&sb, name + klen, namelen - klen - ksuffixlen);
 695                 strbuf_addstr(&sb, vstar + 1);
 696                 *result = strbuf_detach(&sb, NULL);
 697         }
 698         return ret;
 699 }
 700
 701 static void query_refspecs_multiple(struct refspec *rs,
 702                                     struct refspec_item *query,
 703                                     struct string_list *results)
 704 {
 705         int i;
 706         int find_src = !query->src;
 707
 708         if (find_src && !query->dst)
 709                 error("query_refspecs_multiple: need either src or dst");
 710
 711         for (i = 0; i < rs->nr; i++) {
 712                 struct refspec_item *refspec = &rs->items[i];
 713                 const char *key = find_src ? refspec->dst : refspec->src;
 714                 const char *value = find_src ? refspec->src : refspec->dst;
 715                 const char *needle = find_src ? query->dst : query->src;
 716                 char **result = find_src ? &query->src : &query->dst;
 717
 718                 if (!refspec->dst)
 719                         continue;
 720                 if (refspec->pattern) {
 721                         if (match_name_with_pattern(key, needle, value, result))
 722                                 string_list_append_nodup(results, *result);
 723                 } else if (!strcmp(needle, key)) {
 724                         string_list_append(results, value);
 725                 }
 726         }
 727 }
 728
 729 int query_refspecs(struct refspec *rs, struct refspec_item *query)
 730 {
 731         int i;
 732         int find_src = !query->src;
 733         const char *needle = find_src ? query->dst : query->src;
 734         char **result = find_src ? &query->src : &query->dst;
 735
 736         if (find_src && !query->dst)
 737                 return error("query_refspecs: need either src or dst");
 738
 739         for (i = 0; i < rs->nr; i++) {
 740                 struct refspec_item *refspec = &rs->items[i];
 741                 const char *key = find_src ? refspec->dst : refspec->src;
 742                 const char *value = find_src ? refspec->src : refspec->dst;
 743
 744                 if (!refspec->dst)
 745                         continue;
 746                 if (refspec->pattern) {
 747                         if (match_name_with_pattern(key, needle, value, result)) {
 748                                 query->force = refspec->force;
 749                                 return 0;
 750                         }
 751                 } else if (!strcmp(needle, key)) {
 752                         *result = xstrdup(value);
 753                         query->force = refspec->force;
 754                         return 0;
 755                 }
 756         }
 757         return -1;
 758 }
 759
 760 char *apply_refspecs(struct refspec *rs, const char *name)
 761 {
 762         struct refspec_item query;
 763
 764         memset(&query, 0, sizeof(struct refspec_item));
 765         query.src = (char *)name;
 766
 767         if (query_refspecs(rs, &query))
 768                 return NULL;
 769
 770         return query.dst;
 771 }
 772
 773 int remote_find_tracking(struct remote *remote, struct refspec_item *refspec)
 774 {
 775         return query_refspecs(&remote->fetch, refspec);
 776 }
 777
 778 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 779                 const char *name)
 780 {
 781         size_t len = strlen(name);
 782         struct ref *ref = xcalloc(1, st_add4(sizeof(*ref), prefixlen, len, 1));
 783         memcpy(ref->name, prefix, prefixlen);
 784         memcpy(ref->name + prefixlen, name, len);
 785         return ref;
 786 }
 787
 788 struct ref *alloc_ref(const char *name)
 789 {
 790         return alloc_ref_with_prefix("", 0, name);
 791 }
 792
 793 struct ref *copy_ref(const struct ref *ref)
 794 {
 795         struct ref *cpy;
 796         size_t len;
 797         if (!ref)
 798                 return NULL;
 799         len = st_add3(sizeof(struct ref), strlen(ref->name), 1);
 800         cpy = xmalloc(len);
 801         memcpy(cpy, ref, len);
 802         cpy->next = NULL;
 803         cpy->symref = xstrdup_or_null(ref->symref);
 804         cpy->remote_status = xstrdup_or_null(ref->remote_status);
 805         cpy->peer_ref = copy_ref(ref->peer_ref);
 806         return cpy;
 807 }
 808
 809 struct ref *copy_ref_list(const struct ref *ref)
 810 {
 811         struct ref *ret = NULL;
 812         struct ref **tail = &ret;
 813         while (ref) {
 814                 *tail = copy_ref(ref);
 815                 ref = ref->next;
 816                 tail = &((*tail)->next);
 817         }
 818         return ret;
 819 }
 820
 821 static void free_ref(struct ref *ref)
 822 {
 823         if (!ref)
 824                 return;
 825         free_ref(ref->peer_ref);
 826         free(ref->remote_status);
 827         free(ref->symref);
 828         free(ref);
 829 }
 830
 831 void free_refs(struct ref *ref)
 832 {
 833         struct ref *next;
 834         while (ref) {
 835                 next = ref->next;
 836                 free_ref(ref);
 837                 ref = next;
 838         }
 839 }
 840
 841 int ref_compare_name(const void *va, const void *vb)
 842 {
 843         const struct ref *a = va, *b = vb;
 844         return strcmp(a->name, b->name);
 845 }
 846
 847 static void *ref_list_get_next(const void *a)
 848 {
 849         return ((const struct ref *)a)->next;
 850 }
 851
 852 static void ref_list_set_next(void *a, void *next)
 853 {
 854         ((struct ref *)a)->next = next;
 855 }
 856
 857 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
 858 {
 859         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
 860 }
 861
 862 int count_refspec_match(const char *pattern,
 863                         struct ref *refs,
 864                         struct ref **matched_ref)
 865 {
 866         int patlen = strlen(pattern);
 867         struct ref *matched_weak = NULL;
 868         struct ref *matched = NULL;
 869         int weak_match = 0;
 870         int match = 0;
 871
 872         for (weak_match = match = 0; refs; refs = refs->next) {
 873                 char *name = refs->name;
 874                 int namelen = strlen(name);
 875
 876                 if (!refname_match(pattern, name))
 877                         continue;
 878
 879                 /* A match is "weak" if it is with refs outside
 880                  * heads or tags, and did not specify the pattern
 881                  * in full (e.g. "refs/remotes/origin/master") or at
 882                  * least from the toplevel (e.g. "remotes/origin/master");
 883                  * otherwise "git push $URL master" would result in
 884                  * ambiguity between remotes/origin/master and heads/master
 885                  * at the remote site.
 886                  */
 887                 if (namelen != patlen &&
 888                     patlen != namelen - 5 &&
 889                     !starts_with(name, "refs/heads/") &&
 890                     !starts_with(name, "refs/tags/")) {
 891                         /* We want to catch the case where only weak
 892                          * matches are found and there are multiple
 893                          * matches, and where more than one strong
 894                          * matches are found, as ambiguous.  One
 895                          * strong match with zero or more weak matches
 896                          * are acceptable as a unique match.
 897                          */
 898                         matched_weak = refs;
 899                         weak_match++;
 900                 }
 901                 else {
 902                         matched = refs;
 903                         match++;
 904                 }
 905         }
 906         if (!matched) {
 907                 if (matched_ref)
 908                         *matched_ref = matched_weak;
 909                 return weak_match;
 910         }
 911         else {
 912                 if (matched_ref)
 913                         *matched_ref = matched;
 914                 return match;
 915         }
 916 }
 917
 918 static void tail_link_ref(struct ref *ref, struct ref ***tail)
 919 {
 920         **tail = ref;
 921         while (ref->next)
 922                 ref = ref->next;
 923         *tail = &ref->next;
 924 }
 925
 926 static struct ref *alloc_delete_ref(void)
 927 {
 928         struct ref *ref = alloc_ref("(delete)");
 929         oidclr(&ref->new_oid);
 930         return ref;
 931 }
 932
 933 static int try_explicit_object_name(const char *name,
 934                                     struct ref **match)
 935 {
 936         struct object_id oid;
 937
 938         if (!*name) {
 939                 if (match)
 940                         *match = alloc_delete_ref();
 941                 return 0;
 942         }
 943
 944         if (get_oid(name, &oid))
 945                 return -1;
 946
 947         if (match) {
 948                 *match = alloc_ref(name);
 949                 oidcpy(&(*match)->new_oid, &oid);
 950         }
 951         return 0;
 952 }
 953
 954 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
 955 {
 956         struct ref *ret = alloc_ref(name);
 957         tail_link_ref(ret, tail);
 958         return ret;
 959 }
 960
 961 static char *guess_ref(const char *name, struct ref *peer)
 962 {
 963         struct strbuf buf = STRBUF_INIT;
 964
 965         const char *r = resolve_ref_unsafe(peer->name, RESOLVE_REF_READING,
 966                                            NULL, NULL);
 967         if (!r)
 968                 return NULL;
 969
 970         if (starts_with(r, "refs/heads/"))
 971                 strbuf_addstr(&buf, "refs/heads/");
 972         else if (starts_with(r, "refs/tags/"))
 973                 strbuf_addstr(&buf, "refs/tags/");
 974         else
 975                 return NULL;
 976
 977         strbuf_addstr(&buf, name);
 978         return strbuf_detach(&buf, NULL);
 979 }
 980
 981 static int match_explicit_lhs(struct ref *src,
 982                               struct refspec_item *rs,
 983                               struct ref **match,
 984                               int *allocated_match)
 985 {
 986         switch (count_refspec_match(rs->src, src, match)) {
 987         case 1:
 988                 if (allocated_match)
 989                         *allocated_match = 0;
 990                 return 0;
 991         case 0:
 992                 /* The source could be in the get_sha1() format
 993                  * not a reference name.  :refs/other is a
 994                  * way to delete 'other' ref at the remote end.
 995                  */
 996                 if (try_explicit_object_name(rs->src, match) < 0)
 997                         return error("src refspec %s does not match any.", rs->src);
 998                 if (allocated_match)
 999                         *allocated_match = 1;
1000                 return 0;
1001         default:
1002                 return error("src refspec %s matches more than one.", rs->src);
1003         }
1004 }
1005
1006 static int match_explicit(struct ref *src, struct ref *dst,
1007                           struct ref ***dst_tail,
1008                           struct refspec_item *rs)
1009 {
1010         struct ref *matched_src, *matched_dst;
1011         int allocated_src;
1012
1013         const char *dst_value = rs->dst;
1014         char *dst_guess;
1015
1016         if (rs->pattern || rs->matching)
1017                 return 0;
1018
1019         matched_src = matched_dst = NULL;
1020         if (match_explicit_lhs(src, rs, &matched_src, &allocated_src) < 0)
1021                 return -1;
1022
1023         if (!dst_value) {
1024                 int flag;
1025
1026                 dst_value = resolve_ref_unsafe(matched_src->name,
1027                                                RESOLVE_REF_READING,
1028                                                NULL, &flag);
1029                 if (!dst_value ||
1030                     ((flag & REF_ISSYMREF) &&
1031                      !starts_with(dst_value, "refs/heads/")))
1032                         die("%s cannot be resolved to branch.",
1033                             matched_src->name);
1034         }
1035
1036         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1037         case 1:
1038                 break;
1039         case 0:
1040                 if (starts_with(dst_value, "refs/"))
1041                         matched_dst = make_linked_ref(dst_value, dst_tail);
1042                 else if (is_null_oid(&matched_src->new_oid))
1043                         error("unable to delete '%s': remote ref does not exist",
1044                               dst_value);
1045                 else if ((dst_guess = guess_ref(dst_value, matched_src))) {
1046                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1047                         free(dst_guess);
1048                 } else
1049                         error("unable to push to unqualified destination: %s\n"
1050                               "The destination refspec neither matches an "
1051                               "existing ref on the remote nor\n"
1052                               "begins with refs/, and we are unable to "
1053                               "guess a prefix based on the source ref.",
1054                               dst_value);
1055                 break;
1056         default:
1057                 matched_dst = NULL;
1058                 error("dst refspec %s matches more than one.",
1059                       dst_value);
1060                 break;
1061         }
1062         if (!matched_dst)
1063                 return -1;
1064         if (matched_dst->peer_ref)
1065                 return error("dst ref %s receives from more than one src.",
1066                       matched_dst->name);
1067         else {
1068                 matched_dst->peer_ref = allocated_src ?
1069                                         matched_src :
1070                                         copy_ref(matched_src);
1071                 matched_dst->force = rs->force;
1072         }
1073         return 0;
1074 }
1075
1076 static int match_explicit_refs(struct ref *src, struct ref *dst,
1077                                struct ref ***dst_tail, struct refspec *rs)
1078 {
1079         int i, errs;
1080         for (i = errs = 0; i < rs->nr; i++)
1081                 errs += match_explicit(src, dst, dst_tail, &rs->items[i]);
1082         return errs;
1083 }
1084
1085 static char *get_ref_match(const struct refspec *rs, const struct ref *ref,
1086                            int send_mirror, int direction,
1087                            const struct refspec_item **ret_pat)
1088 {
1089         const struct refspec_item *pat;
1090         char *name;
1091         int i;
1092         int matching_refs = -1;
1093         for (i = 0; i < rs->nr; i++) {
1094                 const struct refspec_item *item = &rs->items[i];
1095                 if (item->matching &&
1096                     (matching_refs == -1 || item->force)) {
1097                         matching_refs = i;
1098                         continue;
1099                 }
1100
1101                 if (item->pattern) {
1102                         const char *dst_side = item->dst ? item->dst : item->src;
1103                         int match;
1104                         if (direction == FROM_SRC)
1105                                 match = match_name_with_pattern(item->src, ref->name, dst_side, &name);
1106                         else
1107                                 match = match_name_with_pattern(dst_side, ref->name, item->src, &name);
1108                         if (match) {
1109                                 matching_refs = i;
1110                                 break;
1111                         }
1112                 }
1113         }
1114         if (matching_refs == -1)
1115                 return NULL;
1116
1117         pat = &rs->items[matching_refs];
1118         if (pat->matching) {
1119                 /*
1120                  * "matching refs"; traditionally we pushed everything
1121                  * including refs outside refs/heads/ hierarchy, but
1122                  * that does not make much sense these days.
1123                  */
1124                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1125                         return NULL;
1126                 name = xstrdup(ref->name);
1127         }
1128         if (ret_pat)
1129                 *ret_pat = pat;
1130         return name;
1131 }
1132
1133 static struct ref **tail_ref(struct ref **head)
1134 {
1135         struct ref **tail = head;
1136         while (*tail)
1137                 tail = &((*tail)->next);
1138         return tail;
1139 }
1140
1141 struct tips {
1142         struct commit **tip;
1143         int nr, alloc;
1144 };
1145
1146 static void add_to_tips(struct tips *tips, const struct object_id *oid)
1147 {
1148         struct commit *commit;
1149
1150         if (is_null_oid(oid))
1151                 return;
1152         commit = lookup_commit_reference_gently(oid, 1);
1153         if (!commit || (commit->object.flags & TMP_MARK))
1154                 return;
1155         commit->object.flags |= TMP_MARK;
1156         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1157         tips->tip[tips->nr++] = commit;
1158 }
1159
1160 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1161 {
1162         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1163         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1164         struct string_list_item *item;
1165         struct ref *ref;
1166         struct tips sent_tips;
1167
1168         /*
1169          * Collect everything we know they would have at the end of
1170          * this push, and collect all tags they have.
1171          */
1172         memset(&sent_tips, 0, sizeof(sent_tips));
1173         for (ref = *dst; ref; ref = ref->next) {
1174                 if (ref->peer_ref &&
1175                     !is_null_oid(&ref->peer_ref->new_oid))
1176                         add_to_tips(&sent_tips, &ref->peer_ref->new_oid);
1177                 else
1178                         add_to_tips(&sent_tips, &ref->old_oid);
1179                 if (starts_with(ref->name, "refs/tags/"))
1180                         string_list_append(&dst_tag, ref->name);
1181         }
1182         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1183
1184         string_list_sort(&dst_tag);
1185
1186         /* Collect tags they do not have. */
1187         for (ref = src; ref; ref = ref->next) {
1188                 if (!starts_with(ref->name, "refs/tags/"))
1189                         continue; /* not a tag */
1190                 if (string_list_has_string(&dst_tag, ref->name))
1191                         continue; /* they already have it */
1192                 if (oid_object_info(the_repository, &ref->new_oid, NULL) != OBJ_TAG)
1193                         continue; /* be conservative */
1194                 item = string_list_append(&src_tag, ref->name);
1195                 item->util = ref;
1196         }
1197         string_list_clear(&dst_tag, 0);
1198
1199         /*
1200          * At this point, src_tag lists tags that are missing from
1201          * dst, and sent_tips lists the tips we are pushing or those
1202          * that we know they already have. An element in the src_tag
1203          * that is an ancestor of any of the sent_tips needs to be
1204          * sent to the other side.
1205          */
1206         if (sent_tips.nr) {
1207                 for_each_string_list_item(item, &src_tag) {
1208                         struct ref *ref = item->util;
1209                         struct ref *dst_ref;
1210                         struct commit *commit;
1211
1212                         if (is_null_oid(&ref->new_oid))
1213                                 continue;
1214                         commit = lookup_commit_reference_gently(&ref->new_oid,
1215                                                                 1);
1216                         if (!commit)
1217                                 /* not pushing a commit, which is not an error */
1218                                 continue;
1219
1220                         /*
1221                          * Is this tag, which they do not have, reachable from
1222                          * any of the commits we are sending?
1223                          */
1224                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1225                                 continue;
1226
1227                         /* Add it in */
1228                         dst_ref = make_linked_ref(ref->name, dst_tail);
1229                         oidcpy(&dst_ref->new_oid, &ref->new_oid);
1230                         dst_ref->peer_ref = copy_ref(ref);
1231                 }
1232         }
1233         string_list_clear(&src_tag, 0);
1234         free(sent_tips.tip);
1235 }
1236
1237 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1238 {
1239         for ( ; list; list = list->next)
1240                 if (!strcmp(list->name, name))
1241                         return (struct ref *)list;
1242         return NULL;
1243 }
1244
1245 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1246 {
1247         for ( ; ref; ref = ref->next)
1248                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1249
1250         string_list_sort(ref_index);
1251 }
1252
1253 /*
1254  * Given only the set of local refs, sanity-check the set of push
1255  * refspecs. We can't catch all errors that match_push_refs would,
1256  * but we can catch some errors early before even talking to the
1257  * remote side.
1258  */
1259 int check_push_refs(struct ref *src, struct refspec *rs)
1260 {
1261         int ret = 0;
1262         int i;
1263
1264         for (i = 0; i < rs->nr; i++) {
1265                 struct refspec_item *item = &rs->items[i];
1266
1267                 if (item->pattern || item->matching)
1268                         continue;
1269
1270                 ret |= match_explicit_lhs(src, item, NULL, NULL);
1271         }
1272
1273         return ret;
1274 }
1275
1276 /*
1277  * Given the set of refs the local repository has, the set of refs the
1278  * remote repository has, and the refspec used for push, determine
1279  * what remote refs we will update and with what value by setting
1280  * peer_ref (which object is being pushed) and force (if the push is
1281  * forced) in elements of "dst". The function may add new elements to
1282  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1283  */
1284 int match_push_refs(struct ref *src, struct ref **dst,
1285                     struct refspec *rs, int flags)
1286 {
1287         int send_all = flags & MATCH_REFS_ALL;
1288         int send_mirror = flags & MATCH_REFS_MIRROR;
1289         int send_prune = flags & MATCH_REFS_PRUNE;
1290         int errs;
1291         struct ref *ref, **dst_tail = tail_ref(dst);
1292         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1293
1294         /* If no refspec is provided, use the default ":" */
1295         if (!rs->nr)
1296                 refspec_append(rs, ":");
1297
1298         errs = match_explicit_refs(src, *dst, &dst_tail, rs);
1299
1300         /* pick the remainder */
1301         for (ref = src; ref; ref = ref->next) {
1302                 struct string_list_item *dst_item;
1303                 struct ref *dst_peer;
1304                 const struct refspec_item *pat = NULL;
1305                 char *dst_name;
1306
1307                 dst_name = get_ref_match(rs, ref, send_mirror, FROM_SRC, &pat);
1308                 if (!dst_name)
1309                         continue;
1310
1311                 if (!dst_ref_index.nr)
1312                         prepare_ref_index(&dst_ref_index, *dst);
1313
1314                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1315                 dst_peer = dst_item ? dst_item->util : NULL;
1316                 if (dst_peer) {
1317                         if (dst_peer->peer_ref)
1318                                 /* We're already sending something to this ref. */
1319                                 goto free_name;
1320                 } else {
1321                         if (pat->matching && !(send_all || send_mirror))
1322                                 /*
1323                                  * Remote doesn't have it, and we have no
1324                                  * explicit pattern, and we don't have
1325                                  * --all or --mirror.
1326                                  */
1327                                 goto free_name;
1328
1329                         /* Create a new one and link it */
1330                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1331                         oidcpy(&dst_peer->new_oid, &ref->new_oid);
1332                         string_list_insert(&dst_ref_index,
1333                                 dst_peer->name)->util = dst_peer;
1334                 }
1335                 dst_peer->peer_ref = copy_ref(ref);
1336                 dst_peer->force = pat->force;
1337         free_name:
1338                 free(dst_name);
1339         }
1340
1341         string_list_clear(&dst_ref_index, 0);
1342
1343         if (flags & MATCH_REFS_FOLLOW_TAGS)
1344                 add_missing_tags(src, dst, &dst_tail);
1345
1346         if (send_prune) {
1347                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1348                 /* check for missing refs on the remote */
1349                 for (ref = *dst; ref; ref = ref->next) {
1350                         char *src_name;
1351
1352                         if (ref->peer_ref)
1353                                 /* We're already sending something to this ref. */
1354                                 continue;
1355
1356                         src_name = get_ref_match(rs, ref, send_mirror, FROM_DST, NULL);
1357                         if (src_name) {
1358                                 if (!src_ref_index.nr)
1359                                         prepare_ref_index(&src_ref_index, src);
1360                                 if (!string_list_has_string(&src_ref_index,
1361                                             src_name))
1362                                         ref->peer_ref = alloc_delete_ref();
1363                                 free(src_name);
1364                         }
1365                 }
1366                 string_list_clear(&src_ref_index, 0);
1367         }
1368
1369         if (errs)
1370                 return -1;
1371         return 0;
1372 }
1373
1374 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1375                              int force_update)
1376 {
1377         struct ref *ref;
1378
1379         for (ref = remote_refs; ref; ref = ref->next) {
1380                 int force_ref_update = ref->force || force_update;
1381                 int reject_reason = 0;
1382
1383                 if (ref->peer_ref)
1384                         oidcpy(&ref->new_oid, &ref->peer_ref->new_oid);
1385                 else if (!send_mirror)
1386                         continue;
1387
1388                 ref->deletion = is_null_oid(&ref->new_oid);
1389                 if (!ref->deletion &&
1390                         !oidcmp(&ref->old_oid, &ref->new_oid)) {
1391                         ref->status = REF_STATUS_UPTODATE;
1392                         continue;
1393                 }
1394
1395                 /*
1396                  * If the remote ref has moved and is now different
1397                  * from what we expect, reject any push.
1398                  *
1399                  * It also is an error if the user told us to check
1400                  * with the remote-tracking branch to find the value
1401                  * to expect, but we did not have such a tracking
1402                  * branch.
1403                  */
1404                 if (ref->expect_old_sha1) {
1405                         if (oidcmp(&ref->old_oid, &ref->old_oid_expect))
1406                                 reject_reason = REF_STATUS_REJECT_STALE;
1407                         else
1408                                 /* If the ref isn't stale then force the update. */
1409                                 force_ref_update = 1;
1410                 }
1411
1412                 /*
1413                  * If the update isn't already rejected then check
1414                  * the usual "must fast-forward" rules.
1415                  *
1416                  * Decide whether an individual refspec A:B can be
1417                  * pushed.  The push will succeed if any of the
1418                  * following are true:
1419                  *
1420                  * (1) the remote reference B does not exist
1421                  *
1422                  * (2) the remote reference B is being removed (i.e.,
1423                  *     pushing :B where no source is specified)
1424                  *
1425                  * (3) the destination is not under refs/tags/, and
1426                  *     if the old and new value is a commit, the new
1427                  *     is a descendant of the old.
1428                  *
1429                  * (4) it is forced using the +A:B notation, or by
1430                  *     passing the --force argument
1431                  */
1432
1433                 if (!reject_reason && !ref->deletion && !is_null_oid(&ref->old_oid)) {
1434                         if (starts_with(ref->name, "refs/tags/"))
1435                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1436                         else if (!has_object_file(&ref->old_oid))
1437                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1438                         else if (!lookup_commit_reference_gently(&ref->old_oid, 1) ||
1439                                  !lookup_commit_reference_gently(&ref->new_oid, 1))
1440                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1441                         else if (!ref_newer(&ref->new_oid, &ref->old_oid))
1442                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1443                 }
1444
1445                 /*
1446                  * "--force" will defeat any rejection implemented
1447                  * by the rules above.
1448                  */
1449                 if (!force_ref_update)
1450                         ref->status = reject_reason;
1451                 else if (reject_reason)
1452                         ref->forced_update = 1;
1453         }
1454 }
1455
1456 static void set_merge(struct branch *ret)
1457 {
1458         struct remote *remote;
1459         char *ref;
1460         struct object_id oid;
1461         int i;
1462
1463         if (!ret)
1464                 return; /* no branch */
1465         if (ret->merge)
1466                 return; /* already run */
1467         if (!ret->remote_name || !ret->merge_nr) {
1468                 /*
1469                  * no merge config; let's make sure we don't confuse callers
1470                  * with a non-zero merge_nr but a NULL merge
1471                  */
1472                 ret->merge_nr = 0;
1473                 return;
1474         }
1475
1476         remote = remote_get(ret->remote_name);
1477
1478         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1479         for (i = 0; i < ret->merge_nr; i++) {
1480                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1481                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1482                 if (!remote_find_tracking(remote, ret->merge[i]) ||
1483                     strcmp(ret->remote_name, "."))
1484                         continue;
1485                 if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
1486                              &oid, &ref) == 1)
1487                         ret->merge[i]->dst = ref;
1488                 else
1489                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1490         }
1491 }
1492
1493 struct branch *branch_get(const char *name)
1494 {
1495         struct branch *ret;
1496
1497         read_config();
1498         if (!name || !*name || !strcmp(name, "HEAD"))
1499                 ret = current_branch;
1500         else
1501                 ret = make_branch(name, 0);
1502         set_merge(ret);
1503         return ret;
1504 }
1505
1506 int branch_has_merge_config(struct branch *branch)
1507 {
1508         return branch && !!branch->merge;
1509 }
1510
1511 int branch_merge_matches(struct branch *branch,
1512                                  int i,
1513                                  const char *refname)
1514 {
1515         if (!branch || i < 0 || i >= branch->merge_nr)
1516                 return 0;
1517         return refname_match(branch->merge[i]->src, refname);
1518 }
1519
1520 __attribute__((format (printf,2,3)))
1521 static const char *error_buf(struct strbuf *err, const char *fmt, ...)
1522 {
1523         if (err) {
1524                 va_list ap;
1525                 va_start(ap, fmt);
1526                 strbuf_vaddf(err, fmt, ap);
1527                 va_end(ap);
1528         }
1529         return NULL;
1530 }
1531
1532 const char *branch_get_upstream(struct branch *branch, struct strbuf *err)
1533 {
1534         if (!branch)
1535                 return error_buf(err, _("HEAD does not point to a branch"));
1536
1537         if (!branch->merge || !branch->merge[0]) {
1538                 /*
1539                  * no merge config; is it because the user didn't define any,
1540                  * or because it is not a real branch, and get_branch
1541                  * auto-vivified it?
1542                  */
1543                 if (!ref_exists(branch->refname))
1544                         return error_buf(err, _("no such branch: '%s'"),
1545                                          branch->name);
1546                 return error_buf(err,
1547                                  _("no upstream configured for branch '%s'"),
1548                                  branch->name);
1549         }
1550
1551         if (!branch->merge[0]->dst)
1552                 return error_buf(err,
1553                                  _("upstream branch '%s' not stored as a remote-tracking branch"),
1554                                  branch->merge[0]->src);
1555
1556         return branch->merge[0]->dst;
1557 }
1558
1559 static const char *tracking_for_push_dest(struct remote *remote,
1560                                           const char *refname,
1561                                           struct strbuf *err)
1562 {
1563         char *ret;
1564
1565         ret = apply_refspecs(&remote->fetch, refname);
1566         if (!ret)
1567                 return error_buf(err,
1568                                  _("push destination '%s' on remote '%s' has no local tracking branch"),
1569                                  refname, remote->name);
1570         return ret;
1571 }
1572
1573 static const char *branch_get_push_1(struct branch *branch, struct strbuf *err)
1574 {
1575         struct remote *remote;
1576
1577         remote = remote_get(pushremote_for_branch(branch, NULL));
1578         if (!remote)
1579                 return error_buf(err,
1580                                  _("branch '%s' has no remote for pushing"),
1581                                  branch->name);
1582
1583         if (remote->push.nr) {
1584                 char *dst;
1585                 const char *ret;
1586
1587                 dst = apply_refspecs(&remote->push, branch->refname);
1588                 if (!dst)
1589                         return error_buf(err,
1590                                          _("push refspecs for '%s' do not include '%s'"),
1591                                          remote->name, branch->name);
1592
1593                 ret = tracking_for_push_dest(remote, dst, err);
1594                 free(dst);
1595                 return ret;
1596         }
1597
1598         if (remote->mirror)
1599                 return tracking_for_push_dest(remote, branch->refname, err);
1600
1601         switch (push_default) {
1602         case PUSH_DEFAULT_NOTHING:
1603                 return error_buf(err, _("push has no destination (push.default is 'nothing')"));
1604
1605         case PUSH_DEFAULT_MATCHING:
1606         case PUSH_DEFAULT_CURRENT:
1607                 return tracking_for_push_dest(remote, branch->refname, err);
1608
1609         case PUSH_DEFAULT_UPSTREAM:
1610                 return branch_get_upstream(branch, err);
1611
1612         case PUSH_DEFAULT_UNSPECIFIED:
1613         case PUSH_DEFAULT_SIMPLE:
1614                 {
1615                         const char *up, *cur;
1616
1617                         up = branch_get_upstream(branch, err);
1618                         if (!up)
1619                                 return NULL;
1620                         cur = tracking_for_push_dest(remote, branch->refname, err);
1621                         if (!cur)
1622                                 return NULL;
1623                         if (strcmp(cur, up))
1624                                 return error_buf(err,
1625                                                  _("cannot resolve 'simple' push to a single destination"));
1626                         return cur;
1627                 }
1628         }
1629
1630         BUG("unhandled push situation");
1631 }
1632
1633 const char *branch_get_push(struct branch *branch, struct strbuf *err)
1634 {
1635         if (!branch)
1636                 return error_buf(err, _("HEAD does not point to a branch"));
1637
1638         if (!branch->push_tracking_ref)
1639                 branch->push_tracking_ref = branch_get_push_1(branch, err);
1640         return branch->push_tracking_ref;
1641 }
1642
1643 static int ignore_symref_update(const char *refname)
1644 {
1645         int flag;
1646
1647         if (!resolve_ref_unsafe(refname, 0, NULL, &flag))
1648                 return 0; /* non-existing refs are OK */
1649         return (flag & REF_ISSYMREF);
1650 }
1651
1652 /*
1653  * Create and return a list of (struct ref) consisting of copies of
1654  * each remote_ref that matches refspec.  refspec must be a pattern.
1655  * Fill in the copies' peer_ref to describe the local tracking refs to
1656  * which they map.  Omit any references that would map to an existing
1657  * local symbolic ref.
1658  */
1659 static struct ref *get_expanded_map(const struct ref *remote_refs,
1660                                     const struct refspec_item *refspec)
1661 {
1662         const struct ref *ref;
1663         struct ref *ret = NULL;
1664         struct ref **tail = &ret;
1665
1666         for (ref = remote_refs; ref; ref = ref->next) {
1667                 char *expn_name = NULL;
1668
1669                 if (strchr(ref->name, '^'))
1670                         continue; /* a dereference item */
1671                 if (match_name_with_pattern(refspec->src, ref->name,
1672                                             refspec->dst, &expn_name) &&
1673                     !ignore_symref_update(expn_name)) {
1674                         struct ref *cpy = copy_ref(ref);
1675
1676                         cpy->peer_ref = alloc_ref(expn_name);
1677                         if (refspec->force)
1678                                 cpy->peer_ref->force = 1;
1679                         *tail = cpy;
1680                         tail = &cpy->next;
1681                 }
1682                 free(expn_name);
1683         }
1684
1685         return ret;
1686 }
1687
1688 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1689 {
1690         const struct ref *ref;
1691         for (ref = refs; ref; ref = ref->next) {
1692                 if (refname_match(name, ref->name))
1693                         return ref;
1694         }
1695         return NULL;
1696 }
1697
1698 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1699 {
1700         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1701
1702         if (!ref)
1703                 return NULL;
1704
1705         return copy_ref(ref);
1706 }
1707
1708 static struct ref *get_local_ref(const char *name)
1709 {
1710         if (!name || name[0] == '\0')
1711                 return NULL;
1712
1713         if (starts_with(name, "refs/"))
1714                 return alloc_ref(name);
1715
1716         if (starts_with(name, "heads/") ||
1717             starts_with(name, "tags/") ||
1718             starts_with(name, "remotes/"))
1719                 return alloc_ref_with_prefix("refs/", 5, name);
1720
1721         return alloc_ref_with_prefix("refs/heads/", 11, name);
1722 }
1723
1724 int get_fetch_map(const struct ref *remote_refs,
1725                   const struct refspec_item *refspec,
1726                   struct ref ***tail,
1727                   int missing_ok)
1728 {
1729         struct ref *ref_map, **rmp;
1730
1731         if (refspec->pattern) {
1732                 ref_map = get_expanded_map(remote_refs, refspec);
1733         } else {
1734                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1735
1736                 if (refspec->exact_sha1) {
1737                         ref_map = alloc_ref(name);
1738                         get_oid_hex(name, &ref_map->old_oid);
1739                         ref_map->exact_oid = 1;
1740                 } else {
1741                         ref_map = get_remote_ref(remote_refs, name);
1742                 }
1743                 if (!missing_ok && !ref_map)
1744                         die("Couldn't find remote ref %s", name);
1745                 if (ref_map) {
1746                         ref_map->peer_ref = get_local_ref(refspec->dst);
1747                         if (ref_map->peer_ref && refspec->force)
1748                                 ref_map->peer_ref->force = 1;
1749                 }
1750         }
1751
1752         for (rmp = &ref_map; *rmp; ) {
1753                 if ((*rmp)->peer_ref) {
1754                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1755                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1756                                 struct ref *ignore = *rmp;
1757                                 error("* Ignoring funny ref '%s' locally",
1758                                       (*rmp)->peer_ref->name);
1759                                 *rmp = (*rmp)->next;
1760                                 free(ignore->peer_ref);
1761                                 free(ignore);
1762                                 continue;
1763                         }
1764                 }
1765                 rmp = &((*rmp)->next);
1766         }
1767
1768         if (ref_map)
1769                 tail_link_ref(ref_map, tail);
1770
1771         return 0;
1772 }
1773
1774 int resolve_remote_symref(struct ref *ref, struct ref *list)
1775 {
1776         if (!ref->symref)
1777                 return 0;
1778         for (; list; list = list->next)
1779                 if (!strcmp(ref->symref, list->name)) {
1780                         oidcpy(&ref->old_oid, &list->old_oid);
1781                         return 0;
1782                 }
1783         return 1;
1784 }
1785
1786 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1787 {
1788         while (list) {
1789                 struct commit *commit = pop_commit(&list);
1790                 commit->object.flags &= ~mark;
1791         }
1792 }
1793
1794 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
1795 {
1796         struct object *o;
1797         struct commit *old_commit, *new_commit;
1798         struct commit_list *list, *used;
1799         int found = 0;
1800
1801         /*
1802          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
1803          * old_commit.  Otherwise we require --force.
1804          */
1805         o = deref_tag(parse_object(old_oid), NULL, 0);
1806         if (!o || o->type != OBJ_COMMIT)
1807                 return 0;
1808         old_commit = (struct commit *) o;
1809
1810         o = deref_tag(parse_object(new_oid), NULL, 0);
1811         if (!o || o->type != OBJ_COMMIT)
1812                 return 0;
1813         new_commit = (struct commit *) o;
1814
1815         if (parse_commit(new_commit) < 0)
1816                 return 0;
1817
1818         used = list = NULL;
1819         commit_list_insert(new_commit, &list);
1820         while (list) {
1821                 new_commit = pop_most_recent_commit(&list, TMP_MARK);
1822                 commit_list_insert(new_commit, &used);
1823                 if (new_commit == old_commit) {
1824                         found = 1;
1825                         break;
1826                 }
1827         }
1828         unmark_and_free(list, TMP_MARK);
1829         unmark_and_free(used, TMP_MARK);
1830         return found;
1831 }
1832
1833 /*
1834  * Lookup the upstream branch for the given branch and if present, optionally
1835  * compute the commit ahead/behind values for the pair.
1836  *
1837  * If abf is AHEAD_BEHIND_FULL, compute the full ahead/behind and return the
1838  * counts in *num_ours and *num_theirs.  If abf is AHEAD_BEHIND_QUICK, skip
1839  * the (potentially expensive) a/b computation (*num_ours and *num_theirs are
1840  * set to zero).
1841  *
1842  * The name of the upstream branch (or NULL if no upstream is defined) is
1843  * returned via *upstream_name, if it is not itself NULL.
1844  *
1845  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
1846  * upstream defined, or ref does not exist).  Returns 0 if the commits are
1847  * identical.  Returns 1 if commits are different.
1848  */
1849 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
1850                        const char **upstream_name, enum ahead_behind_flags abf)
1851 {
1852         struct object_id oid;
1853         struct commit *ours, *theirs;
1854         struct rev_info revs;
1855         const char *base;
1856         struct argv_array argv = ARGV_ARRAY_INIT;
1857
1858         /* Cannot stat unless we are marked to build on top of somebody else. */
1859         base = branch_get_upstream(branch, NULL);
1860         if (upstream_name)
1861                 *upstream_name = base;
1862         if (!base)
1863                 return -1;
1864
1865         /* Cannot stat if what we used to build on no longer exists */
1866         if (read_ref(base, &oid))
1867                 return -1;
1868         theirs = lookup_commit_reference(&oid);
1869         if (!theirs)
1870                 return -1;
1871
1872         if (read_ref(branch->refname, &oid))
1873                 return -1;
1874         ours = lookup_commit_reference(&oid);
1875         if (!ours)
1876                 return -1;
1877
1878         *num_theirs = *num_ours = 0;
1879
1880         /* are we the same? */
1881         if (theirs == ours)
1882                 return 0;
1883         if (abf == AHEAD_BEHIND_QUICK)
1884                 return 1;
1885         if (abf != AHEAD_BEHIND_FULL)
1886                 BUG("stat_tracking_info: invalid abf '%d'", abf);
1887
1888         /* Run "rev-list --left-right ours...theirs" internally... */
1889         argv_array_push(&argv, ""); /* ignored */
1890         argv_array_push(&argv, "--left-right");
1891         argv_array_pushf(&argv, "%s...%s",
1892                          oid_to_hex(&ours->object.oid),
1893                          oid_to_hex(&theirs->object.oid));
1894         argv_array_push(&argv, "--");
1895
1896         init_revisions(&revs, NULL);
1897         setup_revisions(argv.argc, argv.argv, &revs, NULL);
1898         if (prepare_revision_walk(&revs))
1899                 die("revision walk setup failed");
1900
1901         /* ... and count the commits on each side. */
1902         while (1) {
1903                 struct commit *c = get_revision(&revs);
1904                 if (!c)
1905                         break;
1906                 if (c->object.flags & SYMMETRIC_LEFT)
1907                         (*num_ours)++;
1908                 else
1909                         (*num_theirs)++;
1910         }
1911
1912         /* clear object flags smudged by the above traversal */
1913         clear_commit_marks(ours, ALL_REV_FLAGS);
1914         clear_commit_marks(theirs, ALL_REV_FLAGS);
1915
1916         argv_array_clear(&argv);
1917         return 1;
1918 }
1919
1920 /*
1921  * Return true when there is anything to report, otherwise false.
1922  */
1923 int format_tracking_info(struct branch *branch, struct strbuf *sb,
1924                          enum ahead_behind_flags abf)
1925 {
1926         int ours, theirs, sti;
1927         const char *full_base;
1928         char *base;
1929         int upstream_is_gone = 0;
1930
1931         sti = stat_tracking_info(branch, &ours, &theirs, &full_base, abf);
1932         if (sti < 0) {
1933                 if (!full_base)
1934                         return 0;
1935                 upstream_is_gone = 1;
1936         }
1937
1938         base = shorten_unambiguous_ref(full_base, 0);
1939         if (upstream_is_gone) {
1940                 strbuf_addf(sb,
1941                         _("Your branch is based on '%s', but the upstream is gone.\n"),
1942                         base);
1943                 if (advice_status_hints)
1944                         strbuf_addstr(sb,
1945                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
1946         } else if (!sti) {
1947                 strbuf_addf(sb,
1948                         _("Your branch is up to date with '%s'.\n"),
1949                         base);
1950         } else if (abf == AHEAD_BEHIND_QUICK) {
1951                 strbuf_addf(sb,
1952                             _("Your branch and '%s' refer to different commits.\n"),
1953                             base);
1954                 if (advice_status_hints)
1955                         strbuf_addf(sb, _("  (use \"%s\" for details)\n"),
1956                                     "git status --ahead-behind");
1957         } else if (!theirs) {
1958                 strbuf_addf(sb,
1959                         Q_("Your branch is ahead of '%s' by %d commit.\n",
1960                            "Your branch is ahead of '%s' by %d commits.\n",
1961                            ours),
1962                         base, ours);
1963                 if (advice_status_hints)
1964                         strbuf_addstr(sb,
1965                                 _("  (use \"git push\" to publish your local commits)\n"));
1966         } else if (!ours) {
1967                 strbuf_addf(sb,
1968                         Q_("Your branch is behind '%s' by %d commit, "
1969                                "and can be fast-forwarded.\n",
1970                            "Your branch is behind '%s' by %d commits, "
1971                                "and can be fast-forwarded.\n",
1972                            theirs),
1973                         base, theirs);
1974                 if (advice_status_hints)
1975                         strbuf_addstr(sb,
1976                                 _("  (use \"git pull\" to update your local branch)\n"));
1977         } else {
1978                 strbuf_addf(sb,
1979                         Q_("Your branch and '%s' have diverged,\n"
1980                                "and have %d and %d different commit each, "
1981                                "respectively.\n",
1982                            "Your branch and '%s' have diverged,\n"
1983                                "and have %d and %d different commits each, "
1984                                "respectively.\n",
1985                            ours + theirs),
1986                         base, ours, theirs);
1987                 if (advice_status_hints)
1988                         strbuf_addstr(sb,
1989                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
1990         }
1991         free(base);
1992         return 1;
1993 }
1994
1995 static int one_local_ref(const char *refname, const struct object_id *oid,
1996                          int flag, void *cb_data)
1997 {
1998         struct ref ***local_tail = cb_data;
1999         struct ref *ref;
2000
2001         /* we already know it starts with refs/ to get here */
2002         if (check_refname_format(refname + 5, 0))
2003                 return 0;
2004
2005         ref = alloc_ref(refname);
2006         oidcpy(&ref->new_oid, oid);
2007         **local_tail = ref;
2008         *local_tail = &ref->next;
2009         return 0;
2010 }
2011
2012 struct ref *get_local_heads(void)
2013 {
2014         struct ref *local_refs = NULL, **local_tail = &local_refs;
2015
2016         for_each_ref(one_local_ref, &local_tail);
2017         return local_refs;
2018 }
2019
2020 struct ref *guess_remote_head(const struct ref *head,
2021                               const struct ref *refs,
2022                               int all)
2023 {
2024         const struct ref *r;
2025         struct ref *list = NULL;
2026         struct ref **tail = &list;
2027
2028         if (!head)
2029                 return NULL;
2030
2031         /*
2032          * Some transports support directly peeking at
2033          * where HEAD points; if that is the case, then
2034          * we don't have to guess.
2035          */
2036         if (head->symref)
2037                 return copy_ref(find_ref_by_name(refs, head->symref));
2038
2039         /* If refs/heads/master could be right, it is. */
2040         if (!all) {
2041                 r = find_ref_by_name(refs, "refs/heads/master");
2042                 if (r && !oidcmp(&r->old_oid, &head->old_oid))
2043                         return copy_ref(r);
2044         }
2045
2046         /* Look for another ref that points there */
2047         for (r = refs; r; r = r->next) {
2048                 if (r != head &&
2049                     starts_with(r->name, "refs/heads/") &&
2050                     !oidcmp(&r->old_oid, &head->old_oid)) {
2051                         *tail = copy_ref(r);
2052                         tail = &((*tail)->next);
2053                         if (!all)
2054                                 break;
2055                 }
2056         }
2057
2058         return list;
2059 }
2060
2061 struct stale_heads_info {
2062         struct string_list *ref_names;
2063         struct ref **stale_refs_tail;
2064         struct refspec *rs;
2065 };
2066
2067 static int get_stale_heads_cb(const char *refname, const struct object_id *oid,
2068                               int flags, void *cb_data)
2069 {
2070         struct stale_heads_info *info = cb_data;
2071         struct string_list matches = STRING_LIST_INIT_DUP;
2072         struct refspec_item query;
2073         int i, stale = 1;
2074         memset(&query, 0, sizeof(struct refspec_item));
2075         query.dst = (char *)refname;
2076
2077         query_refspecs_multiple(info->rs, &query, &matches);
2078         if (matches.nr == 0)
2079                 goto clean_exit; /* No matches */
2080
2081         /*
2082          * If we did find a suitable refspec and it's not a symref and
2083          * it's not in the list of refs that currently exist in that
2084          * remote, we consider it to be stale. In order to deal with
2085          * overlapping refspecs, we need to go over all of the
2086          * matching refs.
2087          */
2088         if (flags & REF_ISSYMREF)
2089                 goto clean_exit;
2090
2091         for (i = 0; stale && i < matches.nr; i++)
2092                 if (string_list_has_string(info->ref_names, matches.items[i].string))
2093                         stale = 0;
2094
2095         if (stale) {
2096                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2097                 oidcpy(&ref->new_oid, oid);
2098         }
2099
2100 clean_exit:
2101         string_list_clear(&matches, 0);
2102         return 0;
2103 }
2104
2105 struct ref *get_stale_heads(struct refspec *rs, struct ref *fetch_map)
2106 {
2107         struct ref *ref, *stale_refs = NULL;
2108         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2109         struct stale_heads_info info;
2110
2111         info.ref_names = &ref_names;
2112         info.stale_refs_tail = &stale_refs;
2113         info.rs = rs;
2114         for (ref = fetch_map; ref; ref = ref->next)
2115                 string_list_append(&ref_names, ref->name);
2116         string_list_sort(&ref_names);
2117         for_each_ref(get_stale_heads_cb, &info);
2118         string_list_clear(&ref_names, 0);
2119         return stale_refs;
2120 }
2121
2122 /*
2123  * Compare-and-swap
2124  */
2125 static void clear_cas_option(struct push_cas_option *cas)
2126 {
2127         int i;
2128
2129         for (i = 0; i < cas->nr; i++)
2130                 free(cas->entry[i].refname);
2131         free(cas->entry);
2132         memset(cas, 0, sizeof(*cas));
2133 }
2134
2135 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2136                                       const char *refname,
2137                                       size_t refnamelen)
2138 {
2139         struct push_cas *entry;
2140         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2141         entry = &cas->entry[cas->nr++];
2142         memset(entry, 0, sizeof(*entry));
2143         entry->refname = xmemdupz(refname, refnamelen);
2144         return entry;
2145 }
2146
2147 static int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2148 {
2149         const char *colon;
2150         struct push_cas *entry;
2151
2152         if (unset) {
2153                 /* "--no-<option>" */
2154                 clear_cas_option(cas);
2155                 return 0;
2156         }
2157
2158         if (!arg) {
2159                 /* just "--<option>" */
2160                 cas->use_tracking_for_rest = 1;
2161                 return 0;
2162         }
2163
2164         /* "--<option>=refname" or "--<option>=refname:value" */
2165         colon = strchrnul(arg, ':');
2166         entry = add_cas_entry(cas, arg, colon - arg);
2167         if (!*colon)
2168                 entry->use_tracking = 1;
2169         else if (!colon[1])
2170                 oidclr(&entry->expect);
2171         else if (get_oid(colon + 1, &entry->expect))
2172                 return error("cannot parse expected object name '%s'", colon + 1);
2173         return 0;
2174 }
2175
2176 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2177 {
2178         return parse_push_cas_option(opt->value, arg, unset);
2179 }
2180
2181 int is_empty_cas(const struct push_cas_option *cas)
2182 {
2183         return !cas->use_tracking_for_rest && !cas->nr;
2184 }
2185
2186 /*
2187  * Look at remote.fetch refspec and see if we have a remote
2188  * tracking branch for the refname there.  Fill its current
2189  * value in sha1[].
2190  * If we cannot do so, return negative to signal an error.
2191  */
2192 static int remote_tracking(struct remote *remote, const char *refname,
2193                            struct object_id *oid)
2194 {
2195         char *dst;
2196
2197         dst = apply_refspecs(&remote->fetch, refname);
2198         if (!dst)
2199                 return -1; /* no tracking ref for refname at remote */
2200         if (read_ref(dst, oid))
2201                 return -1; /* we know what the tracking ref is but we cannot read it */
2202         return 0;
2203 }
2204
2205 static void apply_cas(struct push_cas_option *cas,
2206                       struct remote *remote,
2207                       struct ref *ref)
2208 {
2209         int i;
2210
2211         /* Find an explicit --<option>=<name>[:<value>] entry */
2212         for (i = 0; i < cas->nr; i++) {
2213                 struct push_cas *entry = &cas->entry[i];
2214                 if (!refname_match(entry->refname, ref->name))
2215                         continue;
2216                 ref->expect_old_sha1 = 1;
2217                 if (!entry->use_tracking)
2218                         oidcpy(&ref->old_oid_expect, &entry->expect);
2219                 else if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2220                         oidclr(&ref->old_oid_expect);
2221                 return;
2222         }
2223
2224         /* Are we using "--<option>" to cover all? */
2225         if (!cas->use_tracking_for_rest)
2226                 return;
2227
2228         ref->expect_old_sha1 = 1;
2229         if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2230                 oidclr(&ref->old_oid_expect);
2231 }
2232
2233 void apply_push_cas(struct push_cas_option *cas,
2234                     struct remote *remote,
2235                     struct ref *remote_refs)
2236 {
2237         struct ref *ref;
2238         for (ref = remote_refs; ref; ref = ref->next)
2239                 apply_cas(cas, remote, ref);
2240 }