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

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