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 "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_item *refs, int ref_count, 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 < ref_count; i++) {
 739                 struct refspec_item *refspec = &refs[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->items, rs->nr, &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.items, remote->fetch.nr, 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_item *rs,
1077                                int rs_nr)
1078 {
1079         int i, errs;
1080         for (i = errs = 0; i < rs_nr; i++)
1081                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1082         return errs;
1083 }
1084
1085 static char *get_ref_match(const struct refspec_item *rs, int rs_nr, const struct ref *ref,
1086                 int send_mirror, int direction, 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                 if (rs[i].matching &&
1094                     (matching_refs == -1 || rs[i].force)) {
1095                         matching_refs = i;
1096                         continue;
1097                 }
1098
1099                 if (rs[i].pattern) {
1100                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1101                         int match;
1102                         if (direction == FROM_SRC)
1103                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1104                         else
1105                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1106                         if (match) {
1107                                 matching_refs = i;
1108                                 break;
1109                         }
1110                 }
1111         }
1112         if (matching_refs == -1)
1113                 return NULL;
1114
1115         pat = rs + matching_refs;
1116         if (pat->matching) {
1117                 /*
1118                  * "matching refs"; traditionally we pushed everything
1119                  * including refs outside refs/heads/ hierarchy, but
1120                  * that does not make much sense these days.
1121                  */
1122                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1123                         return NULL;
1124                 name = xstrdup(ref->name);
1125         }
1126         if (ret_pat)
1127                 *ret_pat = pat;
1128         return name;
1129 }
1130
1131 static struct ref **tail_ref(struct ref **head)
1132 {
1133         struct ref **tail = head;
1134         while (*tail)
1135                 tail = &((*tail)->next);
1136         return tail;
1137 }
1138
1139 struct tips {
1140         struct commit **tip;
1141         int nr, alloc;
1142 };
1143
1144 static void add_to_tips(struct tips *tips, const struct object_id *oid)
1145 {
1146         struct commit *commit;
1147
1148         if (is_null_oid(oid))
1149                 return;
1150         commit = lookup_commit_reference_gently(oid, 1);
1151         if (!commit || (commit->object.flags & TMP_MARK))
1152                 return;
1153         commit->object.flags |= TMP_MARK;
1154         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1155         tips->tip[tips->nr++] = commit;
1156 }
1157
1158 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1159 {
1160         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1161         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1162         struct string_list_item *item;
1163         struct ref *ref;
1164         struct tips sent_tips;
1165
1166         /*
1167          * Collect everything we know they would have at the end of
1168          * this push, and collect all tags they have.
1169          */
1170         memset(&sent_tips, 0, sizeof(sent_tips));
1171         for (ref = *dst; ref; ref = ref->next) {
1172                 if (ref->peer_ref &&
1173                     !is_null_oid(&ref->peer_ref->new_oid))
1174                         add_to_tips(&sent_tips, &ref->peer_ref->new_oid);
1175                 else
1176                         add_to_tips(&sent_tips, &ref->old_oid);
1177                 if (starts_with(ref->name, "refs/tags/"))
1178                         string_list_append(&dst_tag, ref->name);
1179         }
1180         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1181
1182         string_list_sort(&dst_tag);
1183
1184         /* Collect tags they do not have. */
1185         for (ref = src; ref; ref = ref->next) {
1186                 if (!starts_with(ref->name, "refs/tags/"))
1187                         continue; /* not a tag */
1188                 if (string_list_has_string(&dst_tag, ref->name))
1189                         continue; /* they already have it */
1190                 if (oid_object_info(&ref->new_oid, NULL) != OBJ_TAG)
1191                         continue; /* be conservative */
1192                 item = string_list_append(&src_tag, ref->name);
1193                 item->util = ref;
1194         }
1195         string_list_clear(&dst_tag, 0);
1196
1197         /*
1198          * At this point, src_tag lists tags that are missing from
1199          * dst, and sent_tips lists the tips we are pushing or those
1200          * that we know they already have. An element in the src_tag
1201          * that is an ancestor of any of the sent_tips needs to be
1202          * sent to the other side.
1203          */
1204         if (sent_tips.nr) {
1205                 for_each_string_list_item(item, &src_tag) {
1206                         struct ref *ref = item->util;
1207                         struct ref *dst_ref;
1208                         struct commit *commit;
1209
1210                         if (is_null_oid(&ref->new_oid))
1211                                 continue;
1212                         commit = lookup_commit_reference_gently(&ref->new_oid,
1213                                                                 1);
1214                         if (!commit)
1215                                 /* not pushing a commit, which is not an error */
1216                                 continue;
1217
1218                         /*
1219                          * Is this tag, which they do not have, reachable from
1220                          * any of the commits we are sending?
1221                          */
1222                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1223                                 continue;
1224
1225                         /* Add it in */
1226                         dst_ref = make_linked_ref(ref->name, dst_tail);
1227                         oidcpy(&dst_ref->new_oid, &ref->new_oid);
1228                         dst_ref->peer_ref = copy_ref(ref);
1229                 }
1230         }
1231         string_list_clear(&src_tag, 0);
1232         free(sent_tips.tip);
1233 }
1234
1235 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1236 {
1237         for ( ; list; list = list->next)
1238                 if (!strcmp(list->name, name))
1239                         return (struct ref *)list;
1240         return NULL;
1241 }
1242
1243 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1244 {
1245         for ( ; ref; ref = ref->next)
1246                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1247
1248         string_list_sort(ref_index);
1249 }
1250
1251 /*
1252  * Given only the set of local refs, sanity-check the set of push
1253  * refspecs. We can't catch all errors that match_push_refs would,
1254  * but we can catch some errors early before even talking to the
1255  * remote side.
1256  */
1257 int check_push_refs(struct ref *src, int nr_refspec, const char **refspec_names)
1258 {
1259         struct refspec refspec = REFSPEC_INIT_PUSH;
1260         int ret = 0;
1261         int i;
1262
1263         refspec_appendn(&refspec, refspec_names, nr_refspec);
1264
1265         for (i = 0; i < refspec.nr; i++) {
1266                 struct refspec_item *rs = &refspec.items[i];
1267
1268                 if (rs->pattern || rs->matching)
1269                         continue;
1270
1271                 ret |= match_explicit_lhs(src, rs, NULL, NULL);
1272         }
1273
1274         refspec_clear(&refspec);
1275         return ret;
1276 }
1277
1278 /*
1279  * Given the set of refs the local repository has, the set of refs the
1280  * remote repository has, and the refspec used for push, determine
1281  * what remote refs we will update and with what value by setting
1282  * peer_ref (which object is being pushed) and force (if the push is
1283  * forced) in elements of "dst". The function may add new elements to
1284  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1285  */
1286 int match_push_refs(struct ref *src, struct ref **dst,
1287                     int nr_refspec, const char **refspec, int flags)
1288 {
1289         struct refspec rs = REFSPEC_INIT_PUSH;
1290         int send_all = flags & MATCH_REFS_ALL;
1291         int send_mirror = flags & MATCH_REFS_MIRROR;
1292         int send_prune = flags & MATCH_REFS_PRUNE;
1293         int errs;
1294         static const char *default_refspec[] = { ":", NULL };
1295         struct ref *ref, **dst_tail = tail_ref(dst);
1296         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1297
1298         if (!nr_refspec) {
1299                 nr_refspec = 1;
1300                 refspec = default_refspec;
1301         }
1302         refspec_appendn(&rs, refspec, nr_refspec);
1303         errs = match_explicit_refs(src, *dst, &dst_tail, rs.items, rs.nr);
1304
1305         /* pick the remainder */
1306         for (ref = src; ref; ref = ref->next) {
1307                 struct string_list_item *dst_item;
1308                 struct ref *dst_peer;
1309                 const struct refspec_item *pat = NULL;
1310                 char *dst_name;
1311
1312                 dst_name = get_ref_match(rs.items, rs.nr, ref, send_mirror, FROM_SRC, &pat);
1313                 if (!dst_name)
1314                         continue;
1315
1316                 if (!dst_ref_index.nr)
1317                         prepare_ref_index(&dst_ref_index, *dst);
1318
1319                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1320                 dst_peer = dst_item ? dst_item->util : NULL;
1321                 if (dst_peer) {
1322                         if (dst_peer->peer_ref)
1323                                 /* We're already sending something to this ref. */
1324                                 goto free_name;
1325                 } else {
1326                         if (pat->matching && !(send_all || send_mirror))
1327                                 /*
1328                                  * Remote doesn't have it, and we have no
1329                                  * explicit pattern, and we don't have
1330                                  * --all or --mirror.
1331                                  */
1332                                 goto free_name;
1333
1334                         /* Create a new one and link it */
1335                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1336                         oidcpy(&dst_peer->new_oid, &ref->new_oid);
1337                         string_list_insert(&dst_ref_index,
1338                                 dst_peer->name)->util = dst_peer;
1339                 }
1340                 dst_peer->peer_ref = copy_ref(ref);
1341                 dst_peer->force = pat->force;
1342         free_name:
1343                 free(dst_name);
1344         }
1345
1346         string_list_clear(&dst_ref_index, 0);
1347
1348         if (flags & MATCH_REFS_FOLLOW_TAGS)
1349                 add_missing_tags(src, dst, &dst_tail);
1350
1351         if (send_prune) {
1352                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1353                 /* check for missing refs on the remote */
1354                 for (ref = *dst; ref; ref = ref->next) {
1355                         char *src_name;
1356
1357                         if (ref->peer_ref)
1358                                 /* We're already sending something to this ref. */
1359                                 continue;
1360
1361                         src_name = get_ref_match(rs.items, rs.nr, ref, send_mirror, FROM_DST, NULL);
1362                         if (src_name) {
1363                                 if (!src_ref_index.nr)
1364                                         prepare_ref_index(&src_ref_index, src);
1365                                 if (!string_list_has_string(&src_ref_index,
1366                                             src_name))
1367                                         ref->peer_ref = alloc_delete_ref();
1368                                 free(src_name);
1369                         }
1370                 }
1371                 string_list_clear(&src_ref_index, 0);
1372         }
1373
1374         refspec_clear(&rs);
1375
1376         if (errs)
1377                 return -1;
1378         return 0;
1379 }
1380
1381 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1382                              int force_update)
1383 {
1384         struct ref *ref;
1385
1386         for (ref = remote_refs; ref; ref = ref->next) {
1387                 int force_ref_update = ref->force || force_update;
1388                 int reject_reason = 0;
1389
1390                 if (ref->peer_ref)
1391                         oidcpy(&ref->new_oid, &ref->peer_ref->new_oid);
1392                 else if (!send_mirror)
1393                         continue;
1394
1395                 ref->deletion = is_null_oid(&ref->new_oid);
1396                 if (!ref->deletion &&
1397                         !oidcmp(&ref->old_oid, &ref->new_oid)) {
1398                         ref->status = REF_STATUS_UPTODATE;
1399                         continue;
1400                 }
1401
1402                 /*
1403                  * If the remote ref has moved and is now different
1404                  * from what we expect, reject any push.
1405                  *
1406                  * It also is an error if the user told us to check
1407                  * with the remote-tracking branch to find the value
1408                  * to expect, but we did not have such a tracking
1409                  * branch.
1410                  */
1411                 if (ref->expect_old_sha1) {
1412                         if (oidcmp(&ref->old_oid, &ref->old_oid_expect))
1413                                 reject_reason = REF_STATUS_REJECT_STALE;
1414                         else
1415                                 /* If the ref isn't stale then force the update. */
1416                                 force_ref_update = 1;
1417                 }
1418
1419                 /*
1420                  * If the update isn't already rejected then check
1421                  * the usual "must fast-forward" rules.
1422                  *
1423                  * Decide whether an individual refspec A:B can be
1424                  * pushed.  The push will succeed if any of the
1425                  * following are true:
1426                  *
1427                  * (1) the remote reference B does not exist
1428                  *
1429                  * (2) the remote reference B is being removed (i.e.,
1430                  *     pushing :B where no source is specified)
1431                  *
1432                  * (3) the destination is not under refs/tags/, and
1433                  *     if the old and new value is a commit, the new
1434                  *     is a descendant of the old.
1435                  *
1436                  * (4) it is forced using the +A:B notation, or by
1437                  *     passing the --force argument
1438                  */
1439
1440                 if (!reject_reason && !ref->deletion && !is_null_oid(&ref->old_oid)) {
1441                         if (starts_with(ref->name, "refs/tags/"))
1442                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1443                         else if (!has_object_file(&ref->old_oid))
1444                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1445                         else if (!lookup_commit_reference_gently(&ref->old_oid, 1) ||
1446                                  !lookup_commit_reference_gently(&ref->new_oid, 1))
1447                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1448                         else if (!ref_newer(&ref->new_oid, &ref->old_oid))
1449                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1450                 }
1451
1452                 /*
1453                  * "--force" will defeat any rejection implemented
1454                  * by the rules above.
1455                  */
1456                 if (!force_ref_update)
1457                         ref->status = reject_reason;
1458                 else if (reject_reason)
1459                         ref->forced_update = 1;
1460         }
1461 }
1462
1463 static void set_merge(struct branch *ret)
1464 {
1465         struct remote *remote;
1466         char *ref;
1467         struct object_id oid;
1468         int i;
1469
1470         if (!ret)
1471                 return; /* no branch */
1472         if (ret->merge)
1473                 return; /* already run */
1474         if (!ret->remote_name || !ret->merge_nr) {
1475                 /*
1476                  * no merge config; let's make sure we don't confuse callers
1477                  * with a non-zero merge_nr but a NULL merge
1478                  */
1479                 ret->merge_nr = 0;
1480                 return;
1481         }
1482
1483         remote = remote_get(ret->remote_name);
1484
1485         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1486         for (i = 0; i < ret->merge_nr; i++) {
1487                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1488                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1489                 if (!remote_find_tracking(remote, ret->merge[i]) ||
1490                     strcmp(ret->remote_name, "."))
1491                         continue;
1492                 if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
1493                              &oid, &ref) == 1)
1494                         ret->merge[i]->dst = ref;
1495                 else
1496                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1497         }
1498 }
1499
1500 struct branch *branch_get(const char *name)
1501 {
1502         struct branch *ret;
1503
1504         read_config();
1505         if (!name || !*name || !strcmp(name, "HEAD"))
1506                 ret = current_branch;
1507         else
1508                 ret = make_branch(name, 0);
1509         set_merge(ret);
1510         return ret;
1511 }
1512
1513 int branch_has_merge_config(struct branch *branch)
1514 {
1515         return branch && !!branch->merge;
1516 }
1517
1518 int branch_merge_matches(struct branch *branch,
1519                                  int i,
1520                                  const char *refname)
1521 {
1522         if (!branch || i < 0 || i >= branch->merge_nr)
1523                 return 0;
1524         return refname_match(branch->merge[i]->src, refname);
1525 }
1526
1527 __attribute__((format (printf,2,3)))
1528 static const char *error_buf(struct strbuf *err, const char *fmt, ...)
1529 {
1530         if (err) {
1531                 va_list ap;
1532                 va_start(ap, fmt);
1533                 strbuf_vaddf(err, fmt, ap);
1534                 va_end(ap);
1535         }
1536         return NULL;
1537 }
1538
1539 const char *branch_get_upstream(struct branch *branch, struct strbuf *err)
1540 {
1541         if (!branch)
1542                 return error_buf(err, _("HEAD does not point to a branch"));
1543
1544         if (!branch->merge || !branch->merge[0]) {
1545                 /*
1546                  * no merge config; is it because the user didn't define any,
1547                  * or because it is not a real branch, and get_branch
1548                  * auto-vivified it?
1549                  */
1550                 if (!ref_exists(branch->refname))
1551                         return error_buf(err, _("no such branch: '%s'"),
1552                                          branch->name);
1553                 return error_buf(err,
1554                                  _("no upstream configured for branch '%s'"),
1555                                  branch->name);
1556         }
1557
1558         if (!branch->merge[0]->dst)
1559                 return error_buf(err,
1560                                  _("upstream branch '%s' not stored as a remote-tracking branch"),
1561                                  branch->merge[0]->src);
1562
1563         return branch->merge[0]->dst;
1564 }
1565
1566 static const char *tracking_for_push_dest(struct remote *remote,
1567                                           const char *refname,
1568                                           struct strbuf *err)
1569 {
1570         char *ret;
1571
1572         ret = apply_refspecs(&remote->fetch, refname);
1573         if (!ret)
1574                 return error_buf(err,
1575                                  _("push destination '%s' on remote '%s' has no local tracking branch"),
1576                                  refname, remote->name);
1577         return ret;
1578 }
1579
1580 static const char *branch_get_push_1(struct branch *branch, struct strbuf *err)
1581 {
1582         struct remote *remote;
1583
1584         remote = remote_get(pushremote_for_branch(branch, NULL));
1585         if (!remote)
1586                 return error_buf(err,
1587                                  _("branch '%s' has no remote for pushing"),
1588                                  branch->name);
1589
1590         if (remote->push.nr) {
1591                 char *dst;
1592                 const char *ret;
1593
1594                 dst = apply_refspecs(&remote->push, branch->refname);
1595                 if (!dst)
1596                         return error_buf(err,
1597                                          _("push refspecs for '%s' do not include '%s'"),
1598                                          remote->name, branch->name);
1599
1600                 ret = tracking_for_push_dest(remote, dst, err);
1601                 free(dst);
1602                 return ret;
1603         }
1604
1605         if (remote->mirror)
1606                 return tracking_for_push_dest(remote, branch->refname, err);
1607
1608         switch (push_default) {
1609         case PUSH_DEFAULT_NOTHING:
1610                 return error_buf(err, _("push has no destination (push.default is 'nothing')"));
1611
1612         case PUSH_DEFAULT_MATCHING:
1613         case PUSH_DEFAULT_CURRENT:
1614                 return tracking_for_push_dest(remote, branch->refname, err);
1615
1616         case PUSH_DEFAULT_UPSTREAM:
1617                 return branch_get_upstream(branch, err);
1618
1619         case PUSH_DEFAULT_UNSPECIFIED:
1620         case PUSH_DEFAULT_SIMPLE:
1621                 {
1622                         const char *up, *cur;
1623
1624                         up = branch_get_upstream(branch, err);
1625                         if (!up)
1626                                 return NULL;
1627                         cur = tracking_for_push_dest(remote, branch->refname, err);
1628                         if (!cur)
1629                                 return NULL;
1630                         if (strcmp(cur, up))
1631                                 return error_buf(err,
1632                                                  _("cannot resolve 'simple' push to a single destination"));
1633                         return cur;
1634                 }
1635         }
1636
1637         die("BUG: unhandled push situation");
1638 }
1639
1640 const char *branch_get_push(struct branch *branch, struct strbuf *err)
1641 {
1642         if (!branch)
1643                 return error_buf(err, _("HEAD does not point to a branch"));
1644
1645         if (!branch->push_tracking_ref)
1646                 branch->push_tracking_ref = branch_get_push_1(branch, err);
1647         return branch->push_tracking_ref;
1648 }
1649
1650 static int ignore_symref_update(const char *refname)
1651 {
1652         int flag;
1653
1654         if (!resolve_ref_unsafe(refname, 0, NULL, &flag))
1655                 return 0; /* non-existing refs are OK */
1656         return (flag & REF_ISSYMREF);
1657 }
1658
1659 /*
1660  * Create and return a list of (struct ref) consisting of copies of
1661  * each remote_ref that matches refspec.  refspec must be a pattern.
1662  * Fill in the copies' peer_ref to describe the local tracking refs to
1663  * which they map.  Omit any references that would map to an existing
1664  * local symbolic ref.
1665  */
1666 static struct ref *get_expanded_map(const struct ref *remote_refs,
1667                                     const struct refspec_item *refspec)
1668 {
1669         const struct ref *ref;
1670         struct ref *ret = NULL;
1671         struct ref **tail = &ret;
1672
1673         for (ref = remote_refs; ref; ref = ref->next) {
1674                 char *expn_name = NULL;
1675
1676                 if (strchr(ref->name, '^'))
1677                         continue; /* a dereference item */
1678                 if (match_name_with_pattern(refspec->src, ref->name,
1679                                             refspec->dst, &expn_name) &&
1680                     !ignore_symref_update(expn_name)) {
1681                         struct ref *cpy = copy_ref(ref);
1682
1683                         cpy->peer_ref = alloc_ref(expn_name);
1684                         if (refspec->force)
1685                                 cpy->peer_ref->force = 1;
1686                         *tail = cpy;
1687                         tail = &cpy->next;
1688                 }
1689                 free(expn_name);
1690         }
1691
1692         return ret;
1693 }
1694
1695 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1696 {
1697         const struct ref *ref;
1698         for (ref = refs; ref; ref = ref->next) {
1699                 if (refname_match(name, ref->name))
1700                         return ref;
1701         }
1702         return NULL;
1703 }
1704
1705 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1706 {
1707         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1708
1709         if (!ref)
1710                 return NULL;
1711
1712         return copy_ref(ref);
1713 }
1714
1715 static struct ref *get_local_ref(const char *name)
1716 {
1717         if (!name || name[0] == '\0')
1718                 return NULL;
1719
1720         if (starts_with(name, "refs/"))
1721                 return alloc_ref(name);
1722
1723         if (starts_with(name, "heads/") ||
1724             starts_with(name, "tags/") ||
1725             starts_with(name, "remotes/"))
1726                 return alloc_ref_with_prefix("refs/", 5, name);
1727
1728         return alloc_ref_with_prefix("refs/heads/", 11, name);
1729 }
1730
1731 int get_fetch_map(const struct ref *remote_refs,
1732                   const struct refspec_item *refspec,
1733                   struct ref ***tail,
1734                   int missing_ok)
1735 {
1736         struct ref *ref_map, **rmp;
1737
1738         if (refspec->pattern) {
1739                 ref_map = get_expanded_map(remote_refs, refspec);
1740         } else {
1741                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1742
1743                 if (refspec->exact_sha1) {
1744                         ref_map = alloc_ref(name);
1745                         get_oid_hex(name, &ref_map->old_oid);
1746                 } else {
1747                         ref_map = get_remote_ref(remote_refs, name);
1748                 }
1749                 if (!missing_ok && !ref_map)
1750                         die("Couldn't find remote ref %s", name);
1751                 if (ref_map) {
1752                         ref_map->peer_ref = get_local_ref(refspec->dst);
1753                         if (ref_map->peer_ref && refspec->force)
1754                                 ref_map->peer_ref->force = 1;
1755                 }
1756         }
1757
1758         for (rmp = &ref_map; *rmp; ) {
1759                 if ((*rmp)->peer_ref) {
1760                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1761                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1762                                 struct ref *ignore = *rmp;
1763                                 error("* Ignoring funny ref '%s' locally",
1764                                       (*rmp)->peer_ref->name);
1765                                 *rmp = (*rmp)->next;
1766                                 free(ignore->peer_ref);
1767                                 free(ignore);
1768                                 continue;
1769                         }
1770                 }
1771                 rmp = &((*rmp)->next);
1772         }
1773
1774         if (ref_map)
1775                 tail_link_ref(ref_map, tail);
1776
1777         return 0;
1778 }
1779
1780 int resolve_remote_symref(struct ref *ref, struct ref *list)
1781 {
1782         if (!ref->symref)
1783                 return 0;
1784         for (; list; list = list->next)
1785                 if (!strcmp(ref->symref, list->name)) {
1786                         oidcpy(&ref->old_oid, &list->old_oid);
1787                         return 0;
1788                 }
1789         return 1;
1790 }
1791
1792 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1793 {
1794         while (list) {
1795                 struct commit *commit = pop_commit(&list);
1796                 commit->object.flags &= ~mark;
1797         }
1798 }
1799
1800 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
1801 {
1802         struct object *o;
1803         struct commit *old_commit, *new_commit;
1804         struct commit_list *list, *used;
1805         int found = 0;
1806
1807         /*
1808          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
1809          * old_commit.  Otherwise we require --force.
1810          */
1811         o = deref_tag(parse_object(old_oid), NULL, 0);
1812         if (!o || o->type != OBJ_COMMIT)
1813                 return 0;
1814         old_commit = (struct commit *) o;
1815
1816         o = deref_tag(parse_object(new_oid), NULL, 0);
1817         if (!o || o->type != OBJ_COMMIT)
1818                 return 0;
1819         new_commit = (struct commit *) o;
1820
1821         if (parse_commit(new_commit) < 0)
1822                 return 0;
1823
1824         used = list = NULL;
1825         commit_list_insert(new_commit, &list);
1826         while (list) {
1827                 new_commit = pop_most_recent_commit(&list, TMP_MARK);
1828                 commit_list_insert(new_commit, &used);
1829                 if (new_commit == old_commit) {
1830                         found = 1;
1831                         break;
1832                 }
1833         }
1834         unmark_and_free(list, TMP_MARK);
1835         unmark_and_free(used, TMP_MARK);
1836         return found;
1837 }
1838
1839 /*
1840  * Lookup the upstream branch for the given branch and if present, optionally
1841  * compute the commit ahead/behind values for the pair.
1842  *
1843  * If abf is AHEAD_BEHIND_FULL, compute the full ahead/behind and return the
1844  * counts in *num_ours and *num_theirs.  If abf is AHEAD_BEHIND_QUICK, skip
1845  * the (potentially expensive) a/b computation (*num_ours and *num_theirs are
1846  * set to zero).
1847  *
1848  * The name of the upstream branch (or NULL if no upstream is defined) is
1849  * returned via *upstream_name, if it is not itself NULL.
1850  *
1851  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
1852  * upstream defined, or ref does not exist).  Returns 0 if the commits are
1853  * identical.  Returns 1 if commits are different.
1854  */
1855 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
1856                        const char **upstream_name, enum ahead_behind_flags abf)
1857 {
1858         struct object_id oid;
1859         struct commit *ours, *theirs;
1860         struct rev_info revs;
1861         const char *base;
1862         struct argv_array argv = ARGV_ARRAY_INIT;
1863
1864         /* Cannot stat unless we are marked to build on top of somebody else. */
1865         base = branch_get_upstream(branch, NULL);
1866         if (upstream_name)
1867                 *upstream_name = base;
1868         if (!base)
1869                 return -1;
1870
1871         /* Cannot stat if what we used to build on no longer exists */
1872         if (read_ref(base, &oid))
1873                 return -1;
1874         theirs = lookup_commit_reference(&oid);
1875         if (!theirs)
1876                 return -1;
1877
1878         if (read_ref(branch->refname, &oid))
1879                 return -1;
1880         ours = lookup_commit_reference(&oid);
1881         if (!ours)
1882                 return -1;
1883
1884         *num_theirs = *num_ours = 0;
1885
1886         /* are we the same? */
1887         if (theirs == ours)
1888                 return 0;
1889         if (abf == AHEAD_BEHIND_QUICK)
1890                 return 1;
1891         if (abf != AHEAD_BEHIND_FULL)
1892                 BUG("stat_tracking_info: invalid abf '%d'", abf);
1893
1894         /* Run "rev-list --left-right ours...theirs" internally... */
1895         argv_array_push(&argv, ""); /* ignored */
1896         argv_array_push(&argv, "--left-right");
1897         argv_array_pushf(&argv, "%s...%s",
1898                          oid_to_hex(&ours->object.oid),
1899                          oid_to_hex(&theirs->object.oid));
1900         argv_array_push(&argv, "--");
1901
1902         init_revisions(&revs, NULL);
1903         setup_revisions(argv.argc, argv.argv, &revs, NULL);
1904         if (prepare_revision_walk(&revs))
1905                 die("revision walk setup failed");
1906
1907         /* ... and count the commits on each side. */
1908         while (1) {
1909                 struct commit *c = get_revision(&revs);
1910                 if (!c)
1911                         break;
1912                 if (c->object.flags & SYMMETRIC_LEFT)
1913                         (*num_ours)++;
1914                 else
1915                         (*num_theirs)++;
1916         }
1917
1918         /* clear object flags smudged by the above traversal */
1919         clear_commit_marks(ours, ALL_REV_FLAGS);
1920         clear_commit_marks(theirs, ALL_REV_FLAGS);
1921
1922         argv_array_clear(&argv);
1923         return 1;
1924 }
1925
1926 /*
1927  * Return true when there is anything to report, otherwise false.
1928  */
1929 int format_tracking_info(struct branch *branch, struct strbuf *sb,
1930                          enum ahead_behind_flags abf)
1931 {
1932         int ours, theirs, sti;
1933         const char *full_base;
1934         char *base;
1935         int upstream_is_gone = 0;
1936
1937         sti = stat_tracking_info(branch, &ours, &theirs, &full_base, abf);
1938         if (sti < 0) {
1939                 if (!full_base)
1940                         return 0;
1941                 upstream_is_gone = 1;
1942         }
1943
1944         base = shorten_unambiguous_ref(full_base, 0);
1945         if (upstream_is_gone) {
1946                 strbuf_addf(sb,
1947                         _("Your branch is based on '%s', but the upstream is gone.\n"),
1948                         base);
1949                 if (advice_status_hints)
1950                         strbuf_addstr(sb,
1951                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
1952         } else if (!sti) {
1953                 strbuf_addf(sb,
1954                         _("Your branch is up to date with '%s'.\n"),
1955                         base);
1956         } else if (abf == AHEAD_BEHIND_QUICK) {
1957                 strbuf_addf(sb,
1958                             _("Your branch and '%s' refer to different commits.\n"),
1959                             base);
1960                 if (advice_status_hints)
1961                         strbuf_addf(sb, _("  (use \"%s\" for details)\n"),
1962                                     "git status --ahead-behind");
1963         } else if (!theirs) {
1964                 strbuf_addf(sb,
1965                         Q_("Your branch is ahead of '%s' by %d commit.\n",
1966                            "Your branch is ahead of '%s' by %d commits.\n",
1967                            ours),
1968                         base, ours);
1969                 if (advice_status_hints)
1970                         strbuf_addstr(sb,
1971                                 _("  (use \"git push\" to publish your local commits)\n"));
1972         } else if (!ours) {
1973                 strbuf_addf(sb,
1974                         Q_("Your branch is behind '%s' by %d commit, "
1975                                "and can be fast-forwarded.\n",
1976                            "Your branch is behind '%s' by %d commits, "
1977                                "and can be fast-forwarded.\n",
1978                            theirs),
1979                         base, theirs);
1980                 if (advice_status_hints)
1981                         strbuf_addstr(sb,
1982                                 _("  (use \"git pull\" to update your local branch)\n"));
1983         } else {
1984                 strbuf_addf(sb,
1985                         Q_("Your branch and '%s' have diverged,\n"
1986                                "and have %d and %d different commit each, "
1987                                "respectively.\n",
1988                            "Your branch and '%s' have diverged,\n"
1989                                "and have %d and %d different commits each, "
1990                                "respectively.\n",
1991                            ours + theirs),
1992                         base, ours, theirs);
1993                 if (advice_status_hints)
1994                         strbuf_addstr(sb,
1995                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
1996         }
1997         free(base);
1998         return 1;
1999 }
2000
2001 static int one_local_ref(const char *refname, const struct object_id *oid,
2002                          int flag, void *cb_data)
2003 {
2004         struct ref ***local_tail = cb_data;
2005         struct ref *ref;
2006
2007         /* we already know it starts with refs/ to get here */
2008         if (check_refname_format(refname + 5, 0))
2009                 return 0;
2010
2011         ref = alloc_ref(refname);
2012         oidcpy(&ref->new_oid, oid);
2013         **local_tail = ref;
2014         *local_tail = &ref->next;
2015         return 0;
2016 }
2017
2018 struct ref *get_local_heads(void)
2019 {
2020         struct ref *local_refs = NULL, **local_tail = &local_refs;
2021
2022         for_each_ref(one_local_ref, &local_tail);
2023         return local_refs;
2024 }
2025
2026 struct ref *guess_remote_head(const struct ref *head,
2027                               const struct ref *refs,
2028                               int all)
2029 {
2030         const struct ref *r;
2031         struct ref *list = NULL;
2032         struct ref **tail = &list;
2033
2034         if (!head)
2035                 return NULL;
2036
2037         /*
2038          * Some transports support directly peeking at
2039          * where HEAD points; if that is the case, then
2040          * we don't have to guess.
2041          */
2042         if (head->symref)
2043                 return copy_ref(find_ref_by_name(refs, head->symref));
2044
2045         /* If refs/heads/master could be right, it is. */
2046         if (!all) {
2047                 r = find_ref_by_name(refs, "refs/heads/master");
2048                 if (r && !oidcmp(&r->old_oid, &head->old_oid))
2049                         return copy_ref(r);
2050         }
2051
2052         /* Look for another ref that points there */
2053         for (r = refs; r; r = r->next) {
2054                 if (r != head &&
2055                     starts_with(r->name, "refs/heads/") &&
2056                     !oidcmp(&r->old_oid, &head->old_oid)) {
2057                         *tail = copy_ref(r);
2058                         tail = &((*tail)->next);
2059                         if (!all)
2060                                 break;
2061                 }
2062         }
2063
2064         return list;
2065 }
2066
2067 struct stale_heads_info {
2068         struct string_list *ref_names;
2069         struct ref **stale_refs_tail;
2070         struct refspec *rs;
2071 };
2072
2073 static int get_stale_heads_cb(const char *refname, const struct object_id *oid,
2074                               int flags, void *cb_data)
2075 {
2076         struct stale_heads_info *info = cb_data;
2077         struct string_list matches = STRING_LIST_INIT_DUP;
2078         struct refspec_item query;
2079         int i, stale = 1;
2080         memset(&query, 0, sizeof(struct refspec_item));
2081         query.dst = (char *)refname;
2082
2083         query_refspecs_multiple(info->rs, &query, &matches);
2084         if (matches.nr == 0)
2085                 goto clean_exit; /* No matches */
2086
2087         /*
2088          * If we did find a suitable refspec and it's not a symref and
2089          * it's not in the list of refs that currently exist in that
2090          * remote, we consider it to be stale. In order to deal with
2091          * overlapping refspecs, we need to go over all of the
2092          * matching refs.
2093          */
2094         if (flags & REF_ISSYMREF)
2095                 goto clean_exit;
2096
2097         for (i = 0; stale && i < matches.nr; i++)
2098                 if (string_list_has_string(info->ref_names, matches.items[i].string))
2099                         stale = 0;
2100
2101         if (stale) {
2102                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2103                 oidcpy(&ref->new_oid, oid);
2104         }
2105
2106 clean_exit:
2107         string_list_clear(&matches, 0);
2108         return 0;
2109 }
2110
2111 struct ref *get_stale_heads(struct refspec *rs, struct ref *fetch_map)
2112 {
2113         struct ref *ref, *stale_refs = NULL;
2114         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2115         struct stale_heads_info info;
2116
2117         info.ref_names = &ref_names;
2118         info.stale_refs_tail = &stale_refs;
2119         info.rs = rs;
2120         for (ref = fetch_map; ref; ref = ref->next)
2121                 string_list_append(&ref_names, ref->name);
2122         string_list_sort(&ref_names);
2123         for_each_ref(get_stale_heads_cb, &info);
2124         string_list_clear(&ref_names, 0);
2125         return stale_refs;
2126 }
2127
2128 /*
2129  * Compare-and-swap
2130  */
2131 static void clear_cas_option(struct push_cas_option *cas)
2132 {
2133         int i;
2134
2135         for (i = 0; i < cas->nr; i++)
2136                 free(cas->entry[i].refname);
2137         free(cas->entry);
2138         memset(cas, 0, sizeof(*cas));
2139 }
2140
2141 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2142                                       const char *refname,
2143                                       size_t refnamelen)
2144 {
2145         struct push_cas *entry;
2146         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2147         entry = &cas->entry[cas->nr++];
2148         memset(entry, 0, sizeof(*entry));
2149         entry->refname = xmemdupz(refname, refnamelen);
2150         return entry;
2151 }
2152
2153 static int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2154 {
2155         const char *colon;
2156         struct push_cas *entry;
2157
2158         if (unset) {
2159                 /* "--no-<option>" */
2160                 clear_cas_option(cas);
2161                 return 0;
2162         }
2163
2164         if (!arg) {
2165                 /* just "--<option>" */
2166                 cas->use_tracking_for_rest = 1;
2167                 return 0;
2168         }
2169
2170         /* "--<option>=refname" or "--<option>=refname:value" */
2171         colon = strchrnul(arg, ':');
2172         entry = add_cas_entry(cas, arg, colon - arg);
2173         if (!*colon)
2174                 entry->use_tracking = 1;
2175         else if (!colon[1])
2176                 oidclr(&entry->expect);
2177         else if (get_oid(colon + 1, &entry->expect))
2178                 return error("cannot parse expected object name '%s'", colon + 1);
2179         return 0;
2180 }
2181
2182 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2183 {
2184         return parse_push_cas_option(opt->value, arg, unset);
2185 }
2186
2187 int is_empty_cas(const struct push_cas_option *cas)
2188 {
2189         return !cas->use_tracking_for_rest && !cas->nr;
2190 }
2191
2192 /*
2193  * Look at remote.fetch refspec and see if we have a remote
2194  * tracking branch for the refname there.  Fill its current
2195  * value in sha1[].
2196  * If we cannot do so, return negative to signal an error.
2197  */
2198 static int remote_tracking(struct remote *remote, const char *refname,
2199                            struct object_id *oid)
2200 {
2201         char *dst;
2202
2203         dst = apply_refspecs(&remote->fetch, refname);
2204         if (!dst)
2205                 return -1; /* no tracking ref for refname at remote */
2206         if (read_ref(dst, oid))
2207                 return -1; /* we know what the tracking ref is but we cannot read it */
2208         return 0;
2209 }
2210
2211 static void apply_cas(struct push_cas_option *cas,
2212                       struct remote *remote,
2213                       struct ref *ref)
2214 {
2215         int i;
2216
2217         /* Find an explicit --<option>=<name>[:<value>] entry */
2218         for (i = 0; i < cas->nr; i++) {
2219                 struct push_cas *entry = &cas->entry[i];
2220                 if (!refname_match(entry->refname, ref->name))
2221                         continue;
2222                 ref->expect_old_sha1 = 1;
2223                 if (!entry->use_tracking)
2224                         oidcpy(&ref->old_oid_expect, &entry->expect);
2225                 else if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2226                         oidclr(&ref->old_oid_expect);
2227                 return;
2228         }
2229
2230         /* Are we using "--<option>" to cover all? */
2231         if (!cas->use_tracking_for_rest)
2232                 return;
2233
2234         ref->expect_old_sha1 = 1;
2235         if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2236                 oidclr(&ref->old_oid_expect);
2237 }
2238
2239 void apply_push_cas(struct push_cas_option *cas,
2240                     struct remote *remote,
2241                     struct ref *remote_refs)
2242 {
2243         struct ref *ref;
2244         for (ref = remote_refs; ref; ref = ref->next)
2245                 apply_cas(cas, remote, ref);
2246 }