remote.c

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