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

   1 /*
   2  * The backend-independent part of the reference module.
   3  */
   4
   5 #include "cache.h"
   6 #include "config.h"
   7 #include "hashmap.h"
   8 #include "lockfile.h"
   9 #include "iterator.h"
  10 #include "refs.h"
  11 #include "refs/refs-internal.h"
  12 #include "run-command.h"
  13 #include "object-store.h"
  14 #include "object.h"
  15 #include "tag.h"
  16 #include "submodule.h"
  17 #include "worktree.h"
  18 #include "strvec.h"
  19 #include "repository.h"
  20 #include "sigchain.h"
  21
  22 /*
  23  * List of all available backends
  24  */
  25 static struct ref_storage_be *refs_backends = &refs_be_files;
  26
  27 static struct ref_storage_be *find_ref_storage_backend(const char *name)
  28 {
  29         struct ref_storage_be *be;
  30         for (be = refs_backends; be; be = be->next)
  31                 if (!strcmp(be->name, name))
  32                         return be;
  33         return NULL;
  34 }
  35
  36 int ref_storage_backend_exists(const char *name)
  37 {
  38         return find_ref_storage_backend(name) != NULL;
  39 }
  40
  41 /*
  42  * How to handle various characters in refnames:
  43  * 0: An acceptable character for refs
  44  * 1: End-of-component
  45  * 2: ., look for a preceding . to reject .. in refs
  46  * 3: {, look for a preceding @ to reject @{ in refs
  47  * 4: A bad character: ASCII control characters, and
  48  *    ":", "?", "[", "\", "^", "~", SP, or TAB
  49  * 5: *, reject unless REFNAME_REFSPEC_PATTERN is set
  50  */
  51 static unsigned char refname_disposition[256] = {
  52         1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
  53         4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
  54         4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 1,
  55         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
  56         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  57         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
  58         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  59         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
  60 };
  61
  62 /*
  63  * Try to read one refname component from the front of refname.
  64  * Return the length of the component found, or -1 if the component is
  65  * not legal.  It is legal if it is something reasonable to have under
  66  * ".git/refs/"; We do not like it if:
  67  *
  68  * - it begins with ".", or
  69  * - it has double dots "..", or
  70  * - it has ASCII control characters, or
  71  * - it has ":", "?", "[", "\", "^", "~", SP, or TAB anywhere, or
  72  * - it has "*" anywhere unless REFNAME_REFSPEC_PATTERN is set, or
  73  * - it ends with a "/", or
  74  * - it ends with ".lock", or
  75  * - it contains a "@{" portion
  76  *
  77  * When sanitized is not NULL, instead of rejecting the input refname
  78  * as an error, try to come up with a usable replacement for the input
  79  * refname in it.
  80  */
  81 static int check_refname_component(const char *refname, int *flags,
  82                                    struct strbuf *sanitized)
  83 {
  84         const char *cp;
  85         char last = '\0';
  86         size_t component_start = 0; /* garbage - not a reasonable initial value */
  87
  88         if (sanitized)
  89                 component_start = sanitized->len;
  90
  91         for (cp = refname; ; cp++) {
  92                 int ch = *cp & 255;
  93                 unsigned char disp = refname_disposition[ch];
  94
  95                 if (sanitized && disp != 1)
  96                         strbuf_addch(sanitized, ch);
  97
  98                 switch (disp) {
  99                 case 1:
 100                         goto out;
 101                 case 2:
 102                         if (last == '.') { /* Refname contains "..". */
 103                                 if (sanitized)
 104                                         /* collapse ".." to single "." */
 105                                         strbuf_setlen(sanitized, sanitized->len - 1);
 106                                 else
 107                                         return -1;
 108                         }
 109                         break;
 110                 case 3:
 111                         if (last == '@') { /* Refname contains "@{". */
 112                                 if (sanitized)
 113                                         sanitized->buf[sanitized->len-1] = '-';
 114                                 else
 115                                         return -1;
 116                         }
 117                         break;
 118                 case 4:
 119                         /* forbidden char */
 120                         if (sanitized)
 121                                 sanitized->buf[sanitized->len-1] = '-';
 122                         else
 123                                 return -1;
 124                         break;
 125                 case 5:
 126                         if (!(*flags & REFNAME_REFSPEC_PATTERN)) {
 127                                 /* refspec can't be a pattern */
 128                                 if (sanitized)
 129                                         sanitized->buf[sanitized->len-1] = '-';
 130                                 else
 131                                         return -1;
 132                         }
 133
 134                         /*
 135                          * Unset the pattern flag so that we only accept
 136                          * a single asterisk for one side of refspec.
 137                          */
 138                         *flags &= ~ REFNAME_REFSPEC_PATTERN;
 139                         break;
 140                 }
 141                 last = ch;
 142         }
 143 out:
 144         if (cp == refname)
 145                 return 0; /* Component has zero length. */
 146
 147         if (refname[0] == '.') { /* Component starts with '.'. */
 148                 if (sanitized)
 149                         sanitized->buf[component_start] = '-';
 150                 else
 151                         return -1;
 152         }
 153         if (cp - refname >= LOCK_SUFFIX_LEN &&
 154             !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN)) {
 155                 if (!sanitized)
 156                         return -1;
 157                 /* Refname ends with ".lock". */
 158                 while (strbuf_strip_suffix(sanitized, LOCK_SUFFIX)) {
 159                         /* try again in case we have .lock.lock */
 160                 }
 161         }
 162         return cp - refname;
 163 }
 164
 165 static int check_or_sanitize_refname(const char *refname, int flags,
 166                                      struct strbuf *sanitized)
 167 {
 168         int component_len, component_count = 0;
 169
 170         if (!strcmp(refname, "@")) {
 171                 /* Refname is a single character '@'. */
 172                 if (sanitized)
 173                         strbuf_addch(sanitized, '-');
 174                 else
 175                         return -1;
 176         }
 177
 178         while (1) {
 179                 if (sanitized && sanitized->len)
 180                         strbuf_complete(sanitized, '/');
 181
 182                 /* We are at the start of a path component. */
 183                 component_len = check_refname_component(refname, &flags,
 184                                                         sanitized);
 185                 if (sanitized && component_len == 0)
 186                         ; /* OK, omit empty component */
 187                 else if (component_len <= 0)
 188                         return -1;
 189
 190                 component_count++;
 191                 if (refname[component_len] == '\0')
 192                         break;
 193                 /* Skip to next component. */
 194                 refname += component_len + 1;
 195         }
 196
 197         if (refname[component_len - 1] == '.') {
 198                 /* Refname ends with '.'. */
 199                 if (sanitized)
 200                         ; /* omit ending dot */
 201                 else
 202                         return -1;
 203         }
 204         if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
 205                 return -1; /* Refname has only one component. */
 206         return 0;
 207 }
 208
 209 int check_refname_format(const char *refname, int flags)
 210 {
 211         return check_or_sanitize_refname(refname, flags, NULL);
 212 }
 213
 214 void sanitize_refname_component(const char *refname, struct strbuf *out)
 215 {
 216         if (check_or_sanitize_refname(refname, REFNAME_ALLOW_ONELEVEL, out))
 217                 BUG("sanitizing refname '%s' check returned error", refname);
 218 }
 219
 220 int refname_is_safe(const char *refname)
 221 {
 222         const char *rest;
 223
 224         if (skip_prefix(refname, "refs/", &rest)) {
 225                 char *buf;
 226                 int result;
 227                 size_t restlen = strlen(rest);
 228
 229                 /* rest must not be empty, or start or end with "/" */
 230                 if (!restlen || *rest == '/' || rest[restlen - 1] == '/')
 231                         return 0;
 232
 233                 /*
 234                  * Does the refname try to escape refs/?
 235                  * For example: refs/foo/../bar is safe but refs/foo/../../bar
 236                  * is not.
 237                  */
 238                 buf = xmallocz(restlen);
 239                 result = !normalize_path_copy(buf, rest) && !strcmp(buf, rest);
 240                 free(buf);
 241                 return result;
 242         }
 243
 244         do {
 245                 if (!isupper(*refname) && *refname != '_')
 246                         return 0;
 247                 refname++;
 248         } while (*refname);
 249         return 1;
 250 }
 251
 252 /*
 253  * Return true if refname, which has the specified oid and flags, can
 254  * be resolved to an object in the database. If the referred-to object
 255  * does not exist, emit a warning and return false.
 256  */
 257 int ref_resolves_to_object(const char *refname,
 258                            const struct object_id *oid,
 259                            unsigned int flags)
 260 {
 261         if (flags & REF_ISBROKEN)
 262                 return 0;
 263         if (!has_object_file(oid)) {
 264                 error(_("%s does not point to a valid object!"), refname);
 265                 return 0;
 266         }
 267         return 1;
 268 }
 269
 270 char *refs_resolve_refdup(struct ref_store *refs,
 271                           const char *refname, int resolve_flags,
 272                           struct object_id *oid, int *flags)
 273 {
 274         const char *result;
 275
 276         result = refs_resolve_ref_unsafe(refs, refname, resolve_flags,
 277                                          oid, flags);
 278         return xstrdup_or_null(result);
 279 }
 280
 281 char *resolve_refdup(const char *refname, int resolve_flags,
 282                      struct object_id *oid, int *flags)
 283 {
 284         return refs_resolve_refdup(get_main_ref_store(the_repository),
 285                                    refname, resolve_flags,
 286                                    oid, flags);
 287 }
 288
 289 /* The argument to filter_refs */
 290 struct ref_filter {
 291         const char *pattern;
 292         const char *prefix;
 293         each_ref_fn *fn;
 294         void *cb_data;
 295 };
 296
 297 int refs_read_ref_full(struct ref_store *refs, const char *refname,
 298                        int resolve_flags, struct object_id *oid, int *flags)
 299 {
 300         if (refs_resolve_ref_unsafe(refs, refname, resolve_flags, oid, flags))
 301                 return 0;
 302         return -1;
 303 }
 304
 305 int read_ref_full(const char *refname, int resolve_flags, struct object_id *oid, int *flags)
 306 {
 307         return refs_read_ref_full(get_main_ref_store(the_repository), refname,
 308                                   resolve_flags, oid, flags);
 309 }
 310
 311 int read_ref(const char *refname, struct object_id *oid)
 312 {
 313         return read_ref_full(refname, RESOLVE_REF_READING, oid, NULL);
 314 }
 315
 316 int refs_ref_exists(struct ref_store *refs, const char *refname)
 317 {
 318         return !!refs_resolve_ref_unsafe(refs, refname, RESOLVE_REF_READING, NULL, NULL);
 319 }
 320
 321 int ref_exists(const char *refname)
 322 {
 323         return refs_ref_exists(get_main_ref_store(the_repository), refname);
 324 }
 325
 326 static int filter_refs(const char *refname, const struct object_id *oid,
 327                            int flags, void *data)
 328 {
 329         struct ref_filter *filter = (struct ref_filter *)data;
 330
 331         if (wildmatch(filter->pattern, refname, 0))
 332                 return 0;
 333         if (filter->prefix)
 334                 skip_prefix(refname, filter->prefix, &refname);
 335         return filter->fn(refname, oid, flags, filter->cb_data);
 336 }
 337
 338 enum peel_status peel_object(const struct object_id *name, struct object_id *oid)
 339 {
 340         struct object *o = lookup_unknown_object(name);
 341
 342         if (o->type == OBJ_NONE) {
 343                 int type = oid_object_info(the_repository, name, NULL);
 344                 if (type < 0 || !object_as_type(o, type, 0))
 345                         return PEEL_INVALID;
 346         }
 347
 348         if (o->type != OBJ_TAG)
 349                 return PEEL_NON_TAG;
 350
 351         o = deref_tag_noverify(o);
 352         if (!o)
 353                 return PEEL_INVALID;
 354
 355         oidcpy(oid, &o->oid);
 356         return PEEL_PEELED;
 357 }
 358
 359 struct warn_if_dangling_data {
 360         FILE *fp;
 361         const char *refname;
 362         const struct string_list *refnames;
 363         const char *msg_fmt;
 364 };
 365
 366 static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
 367                                    int flags, void *cb_data)
 368 {
 369         struct warn_if_dangling_data *d = cb_data;
 370         const char *resolves_to;
 371
 372         if (!(flags & REF_ISSYMREF))
 373                 return 0;
 374
 375         resolves_to = resolve_ref_unsafe(refname, 0, NULL, NULL);
 376         if (!resolves_to
 377             || (d->refname
 378                 ? strcmp(resolves_to, d->refname)
 379                 : !string_list_has_string(d->refnames, resolves_to))) {
 380                 return 0;
 381         }
 382
 383         fprintf(d->fp, d->msg_fmt, refname);
 384         fputc('\n', d->fp);
 385         return 0;
 386 }
 387
 388 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 389 {
 390         struct warn_if_dangling_data data;
 391
 392         data.fp = fp;
 393         data.refname = refname;
 394         data.refnames = NULL;
 395         data.msg_fmt = msg_fmt;
 396         for_each_rawref(warn_if_dangling_symref, &data);
 397 }
 398
 399 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
 400 {
 401         struct warn_if_dangling_data data;
 402
 403         data.fp = fp;
 404         data.refname = NULL;
 405         data.refnames = refnames;
 406         data.msg_fmt = msg_fmt;
 407         for_each_rawref(warn_if_dangling_symref, &data);
 408 }
 409
 410 int refs_for_each_tag_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 411 {
 412         return refs_for_each_ref_in(refs, "refs/tags/", fn, cb_data);
 413 }
 414
 415 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 416 {
 417         return refs_for_each_tag_ref(get_main_ref_store(the_repository), fn, cb_data);
 418 }
 419
 420 int refs_for_each_branch_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 421 {
 422         return refs_for_each_ref_in(refs, "refs/heads/", fn, cb_data);
 423 }
 424
 425 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 426 {
 427         return refs_for_each_branch_ref(get_main_ref_store(the_repository), fn, cb_data);
 428 }
 429
 430 int refs_for_each_remote_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 431 {
 432         return refs_for_each_ref_in(refs, "refs/remotes/", fn, cb_data);
 433 }
 434
 435 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 436 {
 437         return refs_for_each_remote_ref(get_main_ref_store(the_repository), fn, cb_data);
 438 }
 439
 440 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
 441 {
 442         struct strbuf buf = STRBUF_INIT;
 443         int ret = 0;
 444         struct object_id oid;
 445         int flag;
 446
 447         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
 448         if (!read_ref_full(buf.buf, RESOLVE_REF_READING, &oid, &flag))
 449                 ret = fn(buf.buf, &oid, flag, cb_data);
 450         strbuf_release(&buf);
 451
 452         return ret;
 453 }
 454
 455 void normalize_glob_ref(struct string_list_item *item, const char *prefix,
 456                         const char *pattern)
 457 {
 458         struct strbuf normalized_pattern = STRBUF_INIT;
 459
 460         if (*pattern == '/')
 461                 BUG("pattern must not start with '/'");
 462
 463         if (prefix) {
 464                 strbuf_addstr(&normalized_pattern, prefix);
 465         }
 466         else if (!starts_with(pattern, "refs/"))
 467                 strbuf_addstr(&normalized_pattern, "refs/");
 468         strbuf_addstr(&normalized_pattern, pattern);
 469         strbuf_strip_suffix(&normalized_pattern, "/");
 470
 471         item->string = strbuf_detach(&normalized_pattern, NULL);
 472         item->util = has_glob_specials(pattern) ? NULL : item->string;
 473         strbuf_release(&normalized_pattern);
 474 }
 475
 476 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 477         const char *prefix, void *cb_data)
 478 {
 479         struct strbuf real_pattern = STRBUF_INIT;
 480         struct ref_filter filter;
 481         int ret;
 482
 483         if (!prefix && !starts_with(pattern, "refs/"))
 484                 strbuf_addstr(&real_pattern, "refs/");
 485         else if (prefix)
 486                 strbuf_addstr(&real_pattern, prefix);
 487         strbuf_addstr(&real_pattern, pattern);
 488
 489         if (!has_glob_specials(pattern)) {
 490                 /* Append implied '/' '*' if not present. */
 491                 strbuf_complete(&real_pattern, '/');
 492                 /* No need to check for '*', there is none. */
 493                 strbuf_addch(&real_pattern, '*');
 494         }
 495
 496         filter.pattern = real_pattern.buf;
 497         filter.prefix = prefix;
 498         filter.fn = fn;
 499         filter.cb_data = cb_data;
 500         ret = for_each_ref(filter_refs, &filter);
 501
 502         strbuf_release(&real_pattern);
 503         return ret;
 504 }
 505
 506 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
 507 {
 508         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
 509 }
 510
 511 const char *prettify_refname(const char *name)
 512 {
 513         if (skip_prefix(name, "refs/heads/", &name) ||
 514             skip_prefix(name, "refs/tags/", &name) ||
 515             skip_prefix(name, "refs/remotes/", &name))
 516                 ; /* nothing */
 517         return name;
 518 }
 519
 520 static const char *ref_rev_parse_rules[] = {
 521         "%.*s",
 522         "refs/%.*s",
 523         "refs/tags/%.*s",
 524         "refs/heads/%.*s",
 525         "refs/remotes/%.*s",
 526         "refs/remotes/%.*s/HEAD",
 527         NULL
 528 };
 529
 530 #define NUM_REV_PARSE_RULES (ARRAY_SIZE(ref_rev_parse_rules) - 1)
 531
 532 /*
 533  * Is it possible that the caller meant full_name with abbrev_name?
 534  * If so return a non-zero value to signal "yes"; the magnitude of
 535  * the returned value gives the precedence used for disambiguation.
 536  *
 537  * If abbrev_name cannot mean full_name, return 0.
 538  */
 539 int refname_match(const char *abbrev_name, const char *full_name)
 540 {
 541         const char **p;
 542         const int abbrev_name_len = strlen(abbrev_name);
 543         const int num_rules = NUM_REV_PARSE_RULES;
 544
 545         for (p = ref_rev_parse_rules; *p; p++)
 546                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name)))
 547                         return &ref_rev_parse_rules[num_rules] - p;
 548
 549         return 0;
 550 }
 551
 552 /*
 553  * Given a 'prefix' expand it by the rules in 'ref_rev_parse_rules' and add
 554  * the results to 'prefixes'
 555  */
 556 void expand_ref_prefix(struct strvec *prefixes, const char *prefix)
 557 {
 558         const char **p;
 559         int len = strlen(prefix);
 560
 561         for (p = ref_rev_parse_rules; *p; p++)
 562                 strvec_pushf(prefixes, *p, len, prefix);
 563 }
 564
 565 char *repo_default_branch_name(struct repository *r)
 566 {
 567         const char *config_key = "init.defaultbranch";
 568         const char *config_display_key = "init.defaultBranch";
 569         char *ret = NULL, *full_ref;
 570         const char *env = getenv("GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME");
 571
 572         if (env && *env)
 573                 ret = xstrdup(env);
 574         else if (repo_config_get_string(r, config_key, &ret) < 0)
 575                 die(_("could not retrieve `%s`"), config_display_key);
 576
 577         if (!ret)
 578                 ret = xstrdup("master");
 579
 580         full_ref = xstrfmt("refs/heads/%s", ret);
 581         if (check_refname_format(full_ref, 0))
 582                 die(_("invalid branch name: %s = %s"), config_display_key, ret);
 583         free(full_ref);
 584
 585         return ret;
 586 }
 587
 588 const char *git_default_branch_name(void)
 589 {
 590         static char *ret;
 591
 592         if (!ret)
 593                 ret = repo_default_branch_name(the_repository);
 594
 595         return ret;
 596 }
 597
 598 /*
 599  * *string and *len will only be substituted, and *string returned (for
 600  * later free()ing) if the string passed in is a magic short-hand form
 601  * to name a branch.
 602  */
 603 static char *substitute_branch_name(struct repository *r,
 604                                     const char **string, int *len,
 605                                     int nonfatal_dangling_mark)
 606 {
 607         struct strbuf buf = STRBUF_INIT;
 608         struct interpret_branch_name_options options = {
 609                 .nonfatal_dangling_mark = nonfatal_dangling_mark
 610         };
 611         int ret = repo_interpret_branch_name(r, *string, *len, &buf, &options);
 612
 613         if (ret == *len) {
 614                 size_t size;
 615                 *string = strbuf_detach(&buf, &size);
 616                 *len = size;
 617                 return (char *)*string;
 618         }
 619
 620         return NULL;
 621 }
 622
 623 int repo_dwim_ref(struct repository *r, const char *str, int len,
 624                   struct object_id *oid, char **ref, int nonfatal_dangling_mark)
 625 {
 626         char *last_branch = substitute_branch_name(r, &str, &len,
 627                                                    nonfatal_dangling_mark);
 628         int   refs_found  = expand_ref(r, str, len, oid, ref);
 629         free(last_branch);
 630         return refs_found;
 631 }
 632
 633 int expand_ref(struct repository *repo, const char *str, int len,
 634                struct object_id *oid, char **ref)
 635 {
 636         const char **p, *r;
 637         int refs_found = 0;
 638         struct strbuf fullref = STRBUF_INIT;
 639
 640         *ref = NULL;
 641         for (p = ref_rev_parse_rules; *p; p++) {
 642                 struct object_id oid_from_ref;
 643                 struct object_id *this_result;
 644                 int flag;
 645
 646                 this_result = refs_found ? &oid_from_ref : oid;
 647                 strbuf_reset(&fullref);
 648                 strbuf_addf(&fullref, *p, len, str);
 649                 r = refs_resolve_ref_unsafe(get_main_ref_store(repo),
 650                                             fullref.buf, RESOLVE_REF_READING,
 651                                             this_result, &flag);
 652                 if (r) {
 653                         if (!refs_found++)
 654                                 *ref = xstrdup(r);
 655                         if (!warn_ambiguous_refs)
 656                                 break;
 657                 } else if ((flag & REF_ISSYMREF) && strcmp(fullref.buf, "HEAD")) {
 658                         warning(_("ignoring dangling symref %s"), fullref.buf);
 659                 } else if ((flag & REF_ISBROKEN) && strchr(fullref.buf, '/')) {
 660                         warning(_("ignoring broken ref %s"), fullref.buf);
 661                 }
 662         }
 663         strbuf_release(&fullref);
 664         return refs_found;
 665 }
 666
 667 int repo_dwim_log(struct repository *r, const char *str, int len,
 668                   struct object_id *oid, char **log)
 669 {
 670         struct ref_store *refs = get_main_ref_store(r);
 671         char *last_branch = substitute_branch_name(r, &str, &len, 0);
 672         const char **p;
 673         int logs_found = 0;
 674         struct strbuf path = STRBUF_INIT;
 675
 676         *log = NULL;
 677         for (p = ref_rev_parse_rules; *p; p++) {
 678                 struct object_id hash;
 679                 const char *ref, *it;
 680
 681                 strbuf_reset(&path);
 682                 strbuf_addf(&path, *p, len, str);
 683                 ref = refs_resolve_ref_unsafe(refs, path.buf,
 684                                               RESOLVE_REF_READING,
 685                                               &hash, NULL);
 686                 if (!ref)
 687                         continue;
 688                 if (refs_reflog_exists(refs, path.buf))
 689                         it = path.buf;
 690                 else if (strcmp(ref, path.buf) &&
 691                          refs_reflog_exists(refs, ref))
 692                         it = ref;
 693                 else
 694                         continue;
 695                 if (!logs_found++) {
 696                         *log = xstrdup(it);
 697                         oidcpy(oid, &hash);
 698                 }
 699                 if (!warn_ambiguous_refs)
 700                         break;
 701         }
 702         strbuf_release(&path);
 703         free(last_branch);
 704         return logs_found;
 705 }
 706
 707 int dwim_log(const char *str, int len, struct object_id *oid, char **log)
 708 {
 709         return repo_dwim_log(the_repository, str, len, oid, log);
 710 }
 711
 712 static int is_per_worktree_ref(const char *refname)
 713 {
 714         return starts_with(refname, "refs/worktree/") ||
 715                starts_with(refname, "refs/bisect/") ||
 716                starts_with(refname, "refs/rewritten/");
 717 }
 718
 719 static int is_pseudoref_syntax(const char *refname)
 720 {
 721         const char *c;
 722
 723         for (c = refname; *c; c++) {
 724                 if (!isupper(*c) && *c != '-' && *c != '_')
 725                         return 0;
 726         }
 727
 728         return 1;
 729 }
 730
 731 static int is_main_pseudoref_syntax(const char *refname)
 732 {
 733         return skip_prefix(refname, "main-worktree/", &refname) &&
 734                 *refname &&
 735                 is_pseudoref_syntax(refname);
 736 }
 737
 738 static int is_other_pseudoref_syntax(const char *refname)
 739 {
 740         if (!skip_prefix(refname, "worktrees/", &refname))
 741                 return 0;
 742         refname = strchr(refname, '/');
 743         if (!refname || !refname[1])
 744                 return 0;
 745         return is_pseudoref_syntax(refname + 1);
 746 }
 747
 748 enum ref_type ref_type(const char *refname)
 749 {
 750         if (is_per_worktree_ref(refname))
 751                 return REF_TYPE_PER_WORKTREE;
 752         if (is_pseudoref_syntax(refname))
 753                 return REF_TYPE_PSEUDOREF;
 754         if (is_main_pseudoref_syntax(refname))
 755                 return REF_TYPE_MAIN_PSEUDOREF;
 756         if (is_other_pseudoref_syntax(refname))
 757                 return REF_TYPE_OTHER_PSEUDOREF;
 758         return REF_TYPE_NORMAL;
 759 }
 760
 761 long get_files_ref_lock_timeout_ms(void)
 762 {
 763         static int configured = 0;
 764
 765         /* The default timeout is 100 ms: */
 766         static int timeout_ms = 100;
 767
 768         if (!configured) {
 769                 git_config_get_int("core.filesreflocktimeout", &timeout_ms);
 770                 configured = 1;
 771         }
 772
 773         return timeout_ms;
 774 }
 775
 776 int refs_delete_ref(struct ref_store *refs, const char *msg,
 777                     const char *refname,
 778                     const struct object_id *old_oid,
 779                     unsigned int flags)
 780 {
 781         struct ref_transaction *transaction;
 782         struct strbuf err = STRBUF_INIT;
 783
 784         transaction = ref_store_transaction_begin(refs, &err);
 785         if (!transaction ||
 786             ref_transaction_delete(transaction, refname, old_oid,
 787                                    flags, msg, &err) ||
 788             ref_transaction_commit(transaction, &err)) {
 789                 error("%s", err.buf);
 790                 ref_transaction_free(transaction);
 791                 strbuf_release(&err);
 792                 return 1;
 793         }
 794         ref_transaction_free(transaction);
 795         strbuf_release(&err);
 796         return 0;
 797 }
 798
 799 int delete_ref(const char *msg, const char *refname,
 800                const struct object_id *old_oid, unsigned int flags)
 801 {
 802         return refs_delete_ref(get_main_ref_store(the_repository), msg, refname,
 803                                old_oid, flags);
 804 }
 805
 806 static void copy_reflog_msg(struct strbuf *sb, const char *msg)
 807 {
 808         char c;
 809         int wasspace = 1;
 810
 811         while ((c = *msg++)) {
 812                 if (wasspace && isspace(c))
 813                         continue;
 814                 wasspace = isspace(c);
 815                 if (wasspace)
 816                         c = ' ';
 817                 strbuf_addch(sb, c);
 818         }
 819         strbuf_rtrim(sb);
 820 }
 821
 822 static char *normalize_reflog_message(const char *msg)
 823 {
 824         struct strbuf sb = STRBUF_INIT;
 825
 826         if (msg && *msg)
 827                 copy_reflog_msg(&sb, msg);
 828         return strbuf_detach(&sb, NULL);
 829 }
 830
 831 int should_autocreate_reflog(const char *refname)
 832 {
 833         switch (log_all_ref_updates) {
 834         case LOG_REFS_ALWAYS:
 835                 return 1;
 836         case LOG_REFS_NORMAL:
 837                 return starts_with(refname, "refs/heads/") ||
 838                         starts_with(refname, "refs/remotes/") ||
 839                         starts_with(refname, "refs/notes/") ||
 840                         !strcmp(refname, "HEAD");
 841         default:
 842                 return 0;
 843         }
 844 }
 845
 846 int is_branch(const char *refname)
 847 {
 848         return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
 849 }
 850
 851 struct read_ref_at_cb {
 852         const char *refname;
 853         timestamp_t at_time;
 854         int cnt;
 855         int reccnt;
 856         struct object_id *oid;
 857         int found_it;
 858
 859         struct object_id ooid;
 860         struct object_id noid;
 861         int tz;
 862         timestamp_t date;
 863         char **msg;
 864         timestamp_t *cutoff_time;
 865         int *cutoff_tz;
 866         int *cutoff_cnt;
 867 };
 868
 869 static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
 870                 const char *email, timestamp_t timestamp, int tz,
 871                 const char *message, void *cb_data)
 872 {
 873         struct read_ref_at_cb *cb = cb_data;
 874
 875         cb->reccnt++;
 876         cb->tz = tz;
 877         cb->date = timestamp;
 878
 879         if (timestamp <= cb->at_time || cb->cnt == 0) {
 880                 if (cb->msg)
 881                         *cb->msg = xstrdup(message);
 882                 if (cb->cutoff_time)
 883                         *cb->cutoff_time = timestamp;
 884                 if (cb->cutoff_tz)
 885                         *cb->cutoff_tz = tz;
 886                 if (cb->cutoff_cnt)
 887                         *cb->cutoff_cnt = cb->reccnt - 1;
 888                 /*
 889                  * we have not yet updated cb->[n|o]oid so they still
 890                  * hold the values for the previous record.
 891                  */
 892                 if (!is_null_oid(&cb->ooid)) {
 893                         oidcpy(cb->oid, noid);
 894                         if (!oideq(&cb->ooid, noid))
 895                                 warning(_("log for ref %s has gap after %s"),
 896                                         cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
 897                 }
 898                 else if (cb->date == cb->at_time)
 899                         oidcpy(cb->oid, noid);
 900                 else if (!oideq(noid, cb->oid))
 901                         warning(_("log for ref %s unexpectedly ended on %s"),
 902                                 cb->refname, show_date(cb->date, cb->tz,
 903                                                        DATE_MODE(RFC2822)));
 904                 oidcpy(&cb->ooid, ooid);
 905                 oidcpy(&cb->noid, noid);
 906                 cb->found_it = 1;
 907                 return 1;
 908         }
 909         oidcpy(&cb->ooid, ooid);
 910         oidcpy(&cb->noid, noid);
 911         if (cb->cnt > 0)
 912                 cb->cnt--;
 913         return 0;
 914 }
 915
 916 static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
 917                                   const char *email, timestamp_t timestamp,
 918                                   int tz, const char *message, void *cb_data)
 919 {
 920         struct read_ref_at_cb *cb = cb_data;
 921
 922         if (cb->msg)
 923                 *cb->msg = xstrdup(message);
 924         if (cb->cutoff_time)
 925                 *cb->cutoff_time = timestamp;
 926         if (cb->cutoff_tz)
 927                 *cb->cutoff_tz = tz;
 928         if (cb->cutoff_cnt)
 929                 *cb->cutoff_cnt = cb->reccnt;
 930         oidcpy(cb->oid, ooid);
 931         if (is_null_oid(cb->oid))
 932                 oidcpy(cb->oid, noid);
 933         /* We just want the first entry */
 934         return 1;
 935 }
 936
 937 int read_ref_at(struct ref_store *refs, const char *refname,
 938                 unsigned int flags, timestamp_t at_time, int cnt,
 939                 struct object_id *oid, char **msg,
 940                 timestamp_t *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
 941 {
 942         struct read_ref_at_cb cb;
 943
 944         memset(&cb, 0, sizeof(cb));
 945         cb.refname = refname;
 946         cb.at_time = at_time;
 947         cb.cnt = cnt;
 948         cb.msg = msg;
 949         cb.cutoff_time = cutoff_time;
 950         cb.cutoff_tz = cutoff_tz;
 951         cb.cutoff_cnt = cutoff_cnt;
 952         cb.oid = oid;
 953
 954         refs_for_each_reflog_ent_reverse(refs, refname, read_ref_at_ent, &cb);
 955
 956         if (!cb.reccnt) {
 957                 if (flags & GET_OID_QUIETLY)
 958                         exit(128);
 959                 else
 960                         die(_("log for %s is empty"), refname);
 961         }
 962         if (cb.found_it)
 963                 return 0;
 964
 965         refs_for_each_reflog_ent(refs, refname, read_ref_at_ent_oldest, &cb);
 966
 967         return 1;
 968 }
 969
 970 struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
 971                                                     struct strbuf *err)
 972 {
 973         struct ref_transaction *tr;
 974         assert(err);
 975
 976         tr = xcalloc(1, sizeof(struct ref_transaction));
 977         tr->ref_store = refs;
 978         return tr;
 979 }
 980
 981 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 982 {
 983         return ref_store_transaction_begin(get_main_ref_store(the_repository), err);
 984 }
 985
 986 void ref_transaction_free(struct ref_transaction *transaction)
 987 {
 988         size_t i;
 989
 990         if (!transaction)
 991                 return;
 992
 993         switch (transaction->state) {
 994         case REF_TRANSACTION_OPEN:
 995         case REF_TRANSACTION_CLOSED:
 996                 /* OK */
 997                 break;
 998         case REF_TRANSACTION_PREPARED:
 999                 BUG("free called on a prepared reference transaction");
1000                 break;
1001         default:
1002                 BUG("unexpected reference transaction state");
1003                 break;
1004         }
1005
1006         for (i = 0; i < transaction->nr; i++) {
1007                 free(transaction->updates[i]->msg);
1008                 free(transaction->updates[i]);
1009         }
1010         free(transaction->updates);
1011         free(transaction);
1012 }
1013
1014 struct ref_update *ref_transaction_add_update(
1015                 struct ref_transaction *transaction,
1016                 const char *refname, unsigned int flags,
1017                 const struct object_id *new_oid,
1018                 const struct object_id *old_oid,
1019                 const char *msg)
1020 {
1021         struct ref_update *update;
1022
1023         if (transaction->state != REF_TRANSACTION_OPEN)
1024                 BUG("update called for transaction that is not open");
1025
1026         FLEX_ALLOC_STR(update, refname, refname);
1027         ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
1028         transaction->updates[transaction->nr++] = update;
1029
1030         update->flags = flags;
1031
1032         if (flags & REF_HAVE_NEW)
1033                 oidcpy(&update->new_oid, new_oid);
1034         if (flags & REF_HAVE_OLD)
1035                 oidcpy(&update->old_oid, old_oid);
1036         update->msg = normalize_reflog_message(msg);
1037         return update;
1038 }
1039
1040 int ref_transaction_update(struct ref_transaction *transaction,
1041                            const char *refname,
1042                            const struct object_id *new_oid,
1043                            const struct object_id *old_oid,
1044                            unsigned int flags, const char *msg,
1045                            struct strbuf *err)
1046 {
1047         assert(err);
1048
1049         if ((new_oid && !is_null_oid(new_oid)) ?
1050             check_refname_format(refname, REFNAME_ALLOW_ONELEVEL) :
1051             !refname_is_safe(refname)) {
1052                 strbuf_addf(err, _("refusing to update ref with bad name '%s'"),
1053                             refname);
1054                 return -1;
1055         }
1056
1057         if (flags & ~REF_TRANSACTION_UPDATE_ALLOWED_FLAGS)
1058                 BUG("illegal flags 0x%x passed to ref_transaction_update()", flags);
1059
1060         flags |= (new_oid ? REF_HAVE_NEW : 0) | (old_oid ? REF_HAVE_OLD : 0);
1061
1062         ref_transaction_add_update(transaction, refname, flags,
1063                                    new_oid, old_oid, msg);
1064         return 0;
1065 }
1066
1067 int ref_transaction_create(struct ref_transaction *transaction,
1068                            const char *refname,
1069                            const struct object_id *new_oid,
1070                            unsigned int flags, const char *msg,
1071                            struct strbuf *err)
1072 {
1073         if (!new_oid || is_null_oid(new_oid))
1074                 BUG("create called without valid new_oid");
1075         return ref_transaction_update(transaction, refname, new_oid,
1076                                       &null_oid, flags, msg, err);
1077 }
1078
1079 int ref_transaction_delete(struct ref_transaction *transaction,
1080                            const char *refname,
1081                            const struct object_id *old_oid,
1082                            unsigned int flags, const char *msg,
1083                            struct strbuf *err)
1084 {
1085         if (old_oid && is_null_oid(old_oid))
1086                 BUG("delete called with old_oid set to zeros");
1087         return ref_transaction_update(transaction, refname,
1088                                       &null_oid, old_oid,
1089                                       flags, msg, err);
1090 }
1091
1092 int ref_transaction_verify(struct ref_transaction *transaction,
1093                            const char *refname,
1094                            const struct object_id *old_oid,
1095                            unsigned int flags,
1096                            struct strbuf *err)
1097 {
1098         if (!old_oid)
1099                 BUG("verify called with old_oid set to NULL");
1100         return ref_transaction_update(transaction, refname,
1101                                       NULL, old_oid,
1102                                       flags, NULL, err);
1103 }
1104
1105 int refs_update_ref(struct ref_store *refs, const char *msg,
1106                     const char *refname, const struct object_id *new_oid,
1107                     const struct object_id *old_oid, unsigned int flags,
1108                     enum action_on_err onerr)
1109 {
1110         struct ref_transaction *t = NULL;
1111         struct strbuf err = STRBUF_INIT;
1112         int ret = 0;
1113
1114         t = ref_store_transaction_begin(refs, &err);
1115         if (!t ||
1116             ref_transaction_update(t, refname, new_oid, old_oid, flags, msg,
1117                                    &err) ||
1118             ref_transaction_commit(t, &err)) {
1119                 ret = 1;
1120                 ref_transaction_free(t);
1121         }
1122         if (ret) {
1123                 const char *str = _("update_ref failed for ref '%s': %s");
1124
1125                 switch (onerr) {
1126                 case UPDATE_REFS_MSG_ON_ERR:
1127                         error(str, refname, err.buf);
1128                         break;
1129                 case UPDATE_REFS_DIE_ON_ERR:
1130                         die(str, refname, err.buf);
1131                         break;
1132                 case UPDATE_REFS_QUIET_ON_ERR:
1133                         break;
1134                 }
1135                 strbuf_release(&err);
1136                 return 1;
1137         }
1138         strbuf_release(&err);
1139         if (t)
1140                 ref_transaction_free(t);
1141         return 0;
1142 }
1143
1144 int update_ref(const char *msg, const char *refname,
1145                const struct object_id *new_oid,
1146                const struct object_id *old_oid,
1147                unsigned int flags, enum action_on_err onerr)
1148 {
1149         return refs_update_ref(get_main_ref_store(the_repository), msg, refname, new_oid,
1150                                old_oid, flags, onerr);
1151 }
1152
1153 char *refs_shorten_unambiguous_ref(struct ref_store *refs,
1154                                    const char *refname, int strict)
1155 {
1156         int i;
1157         static char **scanf_fmts;
1158         static int nr_rules;
1159         char *short_name;
1160         struct strbuf resolved_buf = STRBUF_INIT;
1161
1162         if (!nr_rules) {
1163                 /*
1164                  * Pre-generate scanf formats from ref_rev_parse_rules[].
1165                  * Generate a format suitable for scanf from a
1166                  * ref_rev_parse_rules rule by interpolating "%s" at the
1167                  * location of the "%.*s".
1168                  */
1169                 size_t total_len = 0;
1170                 size_t offset = 0;
1171
1172                 /* the rule list is NULL terminated, count them first */
1173                 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
1174                         /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
1175                         total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
1176
1177                 scanf_fmts = xmalloc(st_add(st_mult(sizeof(char *), nr_rules), total_len));
1178
1179                 offset = 0;
1180                 for (i = 0; i < nr_rules; i++) {
1181                         assert(offset < total_len);
1182                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
1183                         offset += xsnprintf(scanf_fmts[i], total_len - offset,
1184                                             ref_rev_parse_rules[i], 2, "%s") + 1;
1185                 }
1186         }
1187
1188         /* bail out if there are no rules */
1189         if (!nr_rules)
1190                 return xstrdup(refname);
1191
1192         /* buffer for scanf result, at most refname must fit */
1193         short_name = xstrdup(refname);
1194
1195         /* skip first rule, it will always match */
1196         for (i = nr_rules - 1; i > 0 ; --i) {
1197                 int j;
1198                 int rules_to_fail = i;
1199                 int short_name_len;
1200
1201                 if (1 != sscanf(refname, scanf_fmts[i], short_name))
1202                         continue;
1203
1204                 short_name_len = strlen(short_name);
1205
1206                 /*
1207                  * in strict mode, all (except the matched one) rules
1208                  * must fail to resolve to a valid non-ambiguous ref
1209                  */
1210                 if (strict)
1211                         rules_to_fail = nr_rules;
1212
1213                 /*
1214                  * check if the short name resolves to a valid ref,
1215                  * but use only rules prior to the matched one
1216                  */
1217                 for (j = 0; j < rules_to_fail; j++) {
1218                         const char *rule = ref_rev_parse_rules[j];
1219
1220                         /* skip matched rule */
1221                         if (i == j)
1222                                 continue;
1223
1224                         /*
1225                          * the short name is ambiguous, if it resolves
1226                          * (with this previous rule) to a valid ref
1227                          * read_ref() returns 0 on success
1228                          */
1229                         strbuf_reset(&resolved_buf);
1230                         strbuf_addf(&resolved_buf, rule,
1231                                     short_name_len, short_name);
1232                         if (refs_ref_exists(refs, resolved_buf.buf))
1233                                 break;
1234                 }
1235
1236                 /*
1237                  * short name is non-ambiguous if all previous rules
1238                  * haven't resolved to a valid ref
1239                  */
1240                 if (j == rules_to_fail) {
1241                         strbuf_release(&resolved_buf);
1242                         return short_name;
1243                 }
1244         }
1245
1246         strbuf_release(&resolved_buf);
1247         free(short_name);
1248         return xstrdup(refname);
1249 }
1250
1251 char *shorten_unambiguous_ref(const char *refname, int strict)
1252 {
1253         return refs_shorten_unambiguous_ref(get_main_ref_store(the_repository),
1254                                             refname, strict);
1255 }
1256
1257 static struct string_list *hide_refs;
1258
1259 int parse_hide_refs_config(const char *var, const char *value, const char *section)
1260 {
1261         const char *key;
1262         if (!strcmp("transfer.hiderefs", var) ||
1263             (!parse_config_key(var, section, NULL, NULL, &key) &&
1264              !strcmp(key, "hiderefs"))) {
1265                 char *ref;
1266                 int len;
1267
1268                 if (!value)
1269                         return config_error_nonbool(var);
1270                 ref = xstrdup(value);
1271                 len = strlen(ref);
1272                 while (len && ref[len - 1] == '/')
1273                         ref[--len] = '\0';
1274                 if (!hide_refs) {
1275                         hide_refs = xcalloc(1, sizeof(*hide_refs));
1276                         hide_refs->strdup_strings = 1;
1277                 }
1278                 string_list_append(hide_refs, ref);
1279         }
1280         return 0;
1281 }
1282
1283 int ref_is_hidden(const char *refname, const char *refname_full)
1284 {
1285         int i;
1286
1287         if (!hide_refs)
1288                 return 0;
1289         for (i = hide_refs->nr - 1; i >= 0; i--) {
1290                 const char *match = hide_refs->items[i].string;
1291                 const char *subject;
1292                 int neg = 0;
1293                 const char *p;
1294
1295                 if (*match == '!') {
1296                         neg = 1;
1297                         match++;
1298                 }
1299
1300                 if (*match == '^') {
1301                         subject = refname_full;
1302                         match++;
1303                 } else {
1304                         subject = refname;
1305                 }
1306
1307                 /* refname can be NULL when namespaces are used. */
1308                 if (subject &&
1309                     skip_prefix(subject, match, &p) &&
1310                     (!*p || *p == '/'))
1311                         return !neg;
1312         }
1313         return 0;
1314 }
1315
1316 const char *find_descendant_ref(const char *dirname,
1317                                 const struct string_list *extras,
1318                                 const struct string_list *skip)
1319 {
1320         int pos;
1321
1322         if (!extras)
1323                 return NULL;
1324
1325         /*
1326          * Look at the place where dirname would be inserted into
1327          * extras. If there is an entry at that position that starts
1328          * with dirname (remember, dirname includes the trailing
1329          * slash) and is not in skip, then we have a conflict.
1330          */
1331         for (pos = string_list_find_insert_index(extras, dirname, 0);
1332              pos < extras->nr; pos++) {
1333                 const char *extra_refname = extras->items[pos].string;
1334
1335                 if (!starts_with(extra_refname, dirname))
1336                         break;
1337
1338                 if (!skip || !string_list_has_string(skip, extra_refname))
1339                         return extra_refname;
1340         }
1341         return NULL;
1342 }
1343
1344 int refs_rename_ref_available(struct ref_store *refs,
1345                               const char *old_refname,
1346                               const char *new_refname)
1347 {
1348         struct string_list skip = STRING_LIST_INIT_NODUP;
1349         struct strbuf err = STRBUF_INIT;
1350         int ok;
1351
1352         string_list_insert(&skip, old_refname);
1353         ok = !refs_verify_refname_available(refs, new_refname,
1354                                             NULL, &skip, &err);
1355         if (!ok)
1356                 error("%s", err.buf);
1357
1358         string_list_clear(&skip, 0);
1359         strbuf_release(&err);
1360         return ok;
1361 }
1362
1363 int refs_head_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1364 {
1365         struct object_id oid;
1366         int flag;
1367
1368         if (!refs_read_ref_full(refs, "HEAD", RESOLVE_REF_READING,
1369                                 &oid, &flag))
1370                 return fn("HEAD", &oid, flag, cb_data);
1371
1372         return 0;
1373 }
1374
1375 int head_ref(each_ref_fn fn, void *cb_data)
1376 {
1377         return refs_head_ref(get_main_ref_store(the_repository), fn, cb_data);
1378 }
1379
1380 struct ref_iterator *refs_ref_iterator_begin(
1381                 struct ref_store *refs,
1382                 const char *prefix, int trim, int flags)
1383 {
1384         struct ref_iterator *iter;
1385
1386         if (ref_paranoia < 0)
1387                 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1388         if (ref_paranoia)
1389                 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1390
1391         iter = refs->be->iterator_begin(refs, prefix, flags);
1392
1393         /*
1394          * `iterator_begin()` already takes care of prefix, but we
1395          * might need to do some trimming:
1396          */
1397         if (trim)
1398                 iter = prefix_ref_iterator_begin(iter, "", trim);
1399
1400         /* Sanity check for subclasses: */
1401         if (!iter->ordered)
1402                 BUG("reference iterator is not ordered");
1403
1404         return iter;
1405 }
1406
1407 /*
1408  * Call fn for each reference in the specified submodule for which the
1409  * refname begins with prefix. If trim is non-zero, then trim that
1410  * many characters off the beginning of each refname before passing
1411  * the refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to
1412  * include broken references in the iteration. If fn ever returns a
1413  * non-zero value, stop the iteration and return that value;
1414  * otherwise, return 0.
1415  */
1416 static int do_for_each_repo_ref(struct repository *r, const char *prefix,
1417                                 each_repo_ref_fn fn, int trim, int flags,
1418                                 void *cb_data)
1419 {
1420         struct ref_iterator *iter;
1421         struct ref_store *refs = get_main_ref_store(r);
1422
1423         if (!refs)
1424                 return 0;
1425
1426         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1427
1428         return do_for_each_repo_ref_iterator(r, iter, fn, cb_data);
1429 }
1430
1431 struct do_for_each_ref_help {
1432         each_ref_fn *fn;
1433         void *cb_data;
1434 };
1435
1436 static int do_for_each_ref_helper(struct repository *r,
1437                                   const char *refname,
1438                                   const struct object_id *oid,
1439                                   int flags,
1440                                   void *cb_data)
1441 {
1442         struct do_for_each_ref_help *hp = cb_data;
1443
1444         return hp->fn(refname, oid, flags, hp->cb_data);
1445 }
1446
1447 static int do_for_each_ref(struct ref_store *refs, const char *prefix,
1448                            each_ref_fn fn, int trim, int flags, void *cb_data)
1449 {
1450         struct ref_iterator *iter;
1451         struct do_for_each_ref_help hp = { fn, cb_data };
1452
1453         if (!refs)
1454                 return 0;
1455
1456         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1457
1458         return do_for_each_repo_ref_iterator(the_repository, iter,
1459                                         do_for_each_ref_helper, &hp);
1460 }
1461
1462 int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1463 {
1464         return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
1465 }
1466
1467 int for_each_ref(each_ref_fn fn, void *cb_data)
1468 {
1469         return refs_for_each_ref(get_main_ref_store(the_repository), fn, cb_data);
1470 }
1471
1472 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
1473                          each_ref_fn fn, void *cb_data)
1474 {
1475         return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
1476 }
1477
1478 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1479 {
1480         return refs_for_each_ref_in(get_main_ref_store(the_repository), prefix, fn, cb_data);
1481 }
1482
1483 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1484 {
1485         unsigned int flag = 0;
1486
1487         if (broken)
1488                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1489         return do_for_each_ref(get_main_ref_store(the_repository),
1490                                prefix, fn, 0, flag, cb_data);
1491 }
1492
1493 int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
1494                              each_ref_fn fn, void *cb_data,
1495                              unsigned int broken)
1496 {
1497         unsigned int flag = 0;
1498
1499         if (broken)
1500                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1501         return do_for_each_ref(refs, prefix, fn, 0, flag, cb_data);
1502 }
1503
1504 int for_each_replace_ref(struct repository *r, each_repo_ref_fn fn, void *cb_data)
1505 {
1506         return do_for_each_repo_ref(r, git_replace_ref_base, fn,
1507                                     strlen(git_replace_ref_base),
1508                                     DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1509 }
1510
1511 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1512 {
1513         struct strbuf buf = STRBUF_INIT;
1514         int ret;
1515         strbuf_addf(&buf, "%srefs/", get_git_namespace());
1516         ret = do_for_each_ref(get_main_ref_store(the_repository),
1517                               buf.buf, fn, 0, 0, cb_data);
1518         strbuf_release(&buf);
1519         return ret;
1520 }
1521
1522 int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1523 {
1524         return do_for_each_ref(refs, "", fn, 0,
1525                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1526 }
1527
1528 int for_each_rawref(each_ref_fn fn, void *cb_data)
1529 {
1530         return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
1531 }
1532
1533 static int refs_read_special_head(struct ref_store *ref_store,
1534                                   const char *refname, struct object_id *oid,
1535                                   struct strbuf *referent, unsigned int *type)
1536 {
1537         struct strbuf full_path = STRBUF_INIT;
1538         struct strbuf content = STRBUF_INIT;
1539         int result = -1;
1540         strbuf_addf(&full_path, "%s/%s", ref_store->gitdir, refname);
1541
1542         if (strbuf_read_file(&content, full_path.buf, 0) < 0)
1543                 goto done;
1544
1545         result = parse_loose_ref_contents(content.buf, oid, referent, type);
1546
1547 done:
1548         strbuf_release(&full_path);
1549         strbuf_release(&content);
1550         return result;
1551 }
1552
1553 int refs_read_raw_ref(struct ref_store *ref_store,
1554                       const char *refname, struct object_id *oid,
1555                       struct strbuf *referent, unsigned int *type)
1556 {
1557         if (!strcmp(refname, "FETCH_HEAD") || !strcmp(refname, "MERGE_HEAD")) {
1558                 return refs_read_special_head(ref_store, refname, oid, referent,
1559                                               type);
1560         }
1561
1562         return ref_store->be->read_raw_ref(ref_store, refname, oid, referent,
1563                                            type);
1564 }
1565
1566 /* This function needs to return a meaningful errno on failure */
1567 const char *refs_resolve_ref_unsafe(struct ref_store *refs,
1568                                     const char *refname,
1569                                     int resolve_flags,
1570                                     struct object_id *oid, int *flags)
1571 {
1572         static struct strbuf sb_refname = STRBUF_INIT;
1573         struct object_id unused_oid;
1574         int unused_flags;
1575         int symref_count;
1576
1577         if (!oid)
1578                 oid = &unused_oid;
1579         if (!flags)
1580                 flags = &unused_flags;
1581
1582         *flags = 0;
1583
1584         if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1585                 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1586                     !refname_is_safe(refname)) {
1587                         errno = EINVAL;
1588                         return NULL;
1589                 }
1590
1591                 /*
1592                  * dwim_ref() uses REF_ISBROKEN to distinguish between
1593                  * missing refs and refs that were present but invalid,
1594                  * to complain about the latter to stderr.
1595                  *
1596                  * We don't know whether the ref exists, so don't set
1597                  * REF_ISBROKEN yet.
1598                  */
1599                 *flags |= REF_BAD_NAME;
1600         }
1601
1602         for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
1603                 unsigned int read_flags = 0;
1604
1605                 if (refs_read_raw_ref(refs, refname,
1606                                       oid, &sb_refname, &read_flags)) {
1607                         *flags |= read_flags;
1608
1609                         /* In reading mode, refs must eventually resolve */
1610                         if (resolve_flags & RESOLVE_REF_READING)
1611                                 return NULL;
1612
1613                         /*
1614                          * Otherwise a missing ref is OK. But the files backend
1615                          * may show errors besides ENOENT if there are
1616                          * similarly-named refs.
1617                          */
1618                         if (errno != ENOENT &&
1619                             errno != EISDIR &&
1620                             errno != ENOTDIR)
1621                                 return NULL;
1622
1623                         oidclr(oid);
1624                         if (*flags & REF_BAD_NAME)
1625                                 *flags |= REF_ISBROKEN;
1626                         return refname;
1627                 }
1628
1629                 *flags |= read_flags;
1630
1631                 if (!(read_flags & REF_ISSYMREF)) {
1632                         if (*flags & REF_BAD_NAME) {
1633                                 oidclr(oid);
1634                                 *flags |= REF_ISBROKEN;
1635                         }
1636                         return refname;
1637                 }
1638
1639                 refname = sb_refname.buf;
1640                 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1641                         oidclr(oid);
1642                         return refname;
1643                 }
1644                 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1645                         if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1646                             !refname_is_safe(refname)) {
1647                                 errno = EINVAL;
1648                                 return NULL;
1649                         }
1650
1651                         *flags |= REF_ISBROKEN | REF_BAD_NAME;
1652                 }
1653         }
1654
1655         errno = ELOOP;
1656         return NULL;
1657 }
1658
1659 /* backend functions */
1660 int refs_init_db(struct strbuf *err)
1661 {
1662         struct ref_store *refs = get_main_ref_store(the_repository);
1663
1664         return refs->be->init_db(refs, err);
1665 }
1666
1667 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1668                                struct object_id *oid, int *flags)
1669 {
1670         return refs_resolve_ref_unsafe(get_main_ref_store(the_repository), refname,
1671                                        resolve_flags, oid, flags);
1672 }
1673
1674 int resolve_gitlink_ref(const char *submodule, const char *refname,
1675                         struct object_id *oid)
1676 {
1677         struct ref_store *refs;
1678         int flags;
1679
1680         refs = get_submodule_ref_store(submodule);
1681
1682         if (!refs)
1683                 return -1;
1684
1685         if (!refs_resolve_ref_unsafe(refs, refname, 0, oid, &flags) ||
1686             is_null_oid(oid))
1687                 return -1;
1688         return 0;
1689 }
1690
1691 struct ref_store_hash_entry
1692 {
1693         struct hashmap_entry ent;
1694
1695         struct ref_store *refs;
1696
1697         /* NUL-terminated identifier of the ref store: */
1698         char name[FLEX_ARRAY];
1699 };
1700
1701 static int ref_store_hash_cmp(const void *unused_cmp_data,
1702                               const struct hashmap_entry *eptr,
1703                               const struct hashmap_entry *entry_or_key,
1704                               const void *keydata)
1705 {
1706         const struct ref_store_hash_entry *e1, *e2;
1707         const char *name;
1708
1709         e1 = container_of(eptr, const struct ref_store_hash_entry, ent);
1710         e2 = container_of(entry_or_key, const struct ref_store_hash_entry, ent);
1711         name = keydata ? keydata : e2->name;
1712
1713         return strcmp(e1->name, name);
1714 }
1715
1716 static struct ref_store_hash_entry *alloc_ref_store_hash_entry(
1717                 const char *name, struct ref_store *refs)
1718 {
1719         struct ref_store_hash_entry *entry;
1720
1721         FLEX_ALLOC_STR(entry, name, name);
1722         hashmap_entry_init(&entry->ent, strhash(name));
1723         entry->refs = refs;
1724         return entry;
1725 }
1726
1727 /* A hashmap of ref_stores, stored by submodule name: */
1728 static struct hashmap submodule_ref_stores;
1729
1730 /* A hashmap of ref_stores, stored by worktree id: */
1731 static struct hashmap worktree_ref_stores;
1732
1733 /*
1734  * Look up a ref store by name. If that ref_store hasn't been
1735  * registered yet, return NULL.
1736  */
1737 static struct ref_store *lookup_ref_store_map(struct hashmap *map,
1738                                               const char *name)
1739 {
1740         struct ref_store_hash_entry *entry;
1741         unsigned int hash;
1742
1743         if (!map->tablesize)
1744                 /* It's initialized on demand in register_ref_store(). */
1745                 return NULL;
1746
1747         hash = strhash(name);
1748         entry = hashmap_get_entry_from_hash(map, hash, name,
1749                                         struct ref_store_hash_entry, ent);
1750         return entry ? entry->refs : NULL;
1751 }
1752
1753 /*
1754  * Create, record, and return a ref_store instance for the specified
1755  * gitdir.
1756  */
1757 static struct ref_store *ref_store_init(const char *gitdir,
1758                                         unsigned int flags)
1759 {
1760         const char *be_name = "files";
1761         struct ref_storage_be *be = find_ref_storage_backend(be_name);
1762         struct ref_store *refs;
1763
1764         if (!be)
1765                 BUG("reference backend %s is unknown", be_name);
1766
1767         refs = be->init(gitdir, flags);
1768         return refs;
1769 }
1770
1771 struct ref_store *get_main_ref_store(struct repository *r)
1772 {
1773         if (r->refs_private)
1774                 return r->refs_private;
1775
1776         if (!r->gitdir)
1777                 BUG("attempting to get main_ref_store outside of repository");
1778
1779         r->refs_private = ref_store_init(r->gitdir, REF_STORE_ALL_CAPS);
1780         r->refs_private = maybe_debug_wrap_ref_store(r->gitdir, r->refs_private);
1781         return r->refs_private;
1782 }
1783
1784 /*
1785  * Associate a ref store with a name. It is a fatal error to call this
1786  * function twice for the same name.
1787  */
1788 static void register_ref_store_map(struct hashmap *map,
1789                                    const char *type,
1790                                    struct ref_store *refs,
1791                                    const char *name)
1792 {
1793         struct ref_store_hash_entry *entry;
1794
1795         if (!map->tablesize)
1796                 hashmap_init(map, ref_store_hash_cmp, NULL, 0);
1797
1798         entry = alloc_ref_store_hash_entry(name, refs);
1799         if (hashmap_put(map, &entry->ent))
1800                 BUG("%s ref_store '%s' initialized twice", type, name);
1801 }
1802
1803 struct ref_store *get_submodule_ref_store(const char *submodule)
1804 {
1805         struct strbuf submodule_sb = STRBUF_INIT;
1806         struct ref_store *refs;
1807         char *to_free = NULL;
1808         size_t len;
1809
1810         if (!submodule)
1811                 return NULL;
1812
1813         len = strlen(submodule);
1814         while (len && is_dir_sep(submodule[len - 1]))
1815                 len--;
1816         if (!len)
1817                 return NULL;
1818
1819         if (submodule[len])
1820                 /* We need to strip off one or more trailing slashes */
1821                 submodule = to_free = xmemdupz(submodule, len);
1822
1823         refs = lookup_ref_store_map(&submodule_ref_stores, submodule);
1824         if (refs)
1825                 goto done;
1826
1827         strbuf_addstr(&submodule_sb, submodule);
1828         if (!is_nonbare_repository_dir(&submodule_sb))
1829                 goto done;
1830
1831         if (submodule_to_gitdir(&submodule_sb, submodule))
1832                 goto done;
1833
1834         /* assume that add_submodule_odb() has been called */
1835         refs = ref_store_init(submodule_sb.buf,
1836                               REF_STORE_READ | REF_STORE_ODB);
1837         register_ref_store_map(&submodule_ref_stores, "submodule",
1838                                refs, submodule);
1839
1840 done:
1841         strbuf_release(&submodule_sb);
1842         free(to_free);
1843
1844         return refs;
1845 }
1846
1847 struct ref_store *get_worktree_ref_store(const struct worktree *wt)
1848 {
1849         struct ref_store *refs;
1850         const char *id;
1851
1852         if (wt->is_current)
1853                 return get_main_ref_store(the_repository);
1854
1855         id = wt->id ? wt->id : "/";
1856         refs = lookup_ref_store_map(&worktree_ref_stores, id);
1857         if (refs)
1858                 return refs;
1859
1860         if (wt->id)
1861                 refs = ref_store_init(git_common_path("worktrees/%s", wt->id),
1862                                       REF_STORE_ALL_CAPS);
1863         else
1864                 refs = ref_store_init(get_git_common_dir(),
1865                                       REF_STORE_ALL_CAPS);
1866
1867         if (refs)
1868                 register_ref_store_map(&worktree_ref_stores, "worktree",
1869                                        refs, id);
1870         return refs;
1871 }
1872
1873 void base_ref_store_init(struct ref_store *refs,
1874                          const struct ref_storage_be *be)
1875 {
1876         refs->be = be;
1877 }
1878
1879 /* backend functions */
1880 int refs_pack_refs(struct ref_store *refs, unsigned int flags)
1881 {
1882         return refs->be->pack_refs(refs, flags);
1883 }
1884
1885 int refs_peel_ref(struct ref_store *refs, const char *refname,
1886                   struct object_id *oid)
1887 {
1888         int flag;
1889         struct object_id base;
1890
1891         if (current_ref_iter && current_ref_iter->refname == refname) {
1892                 struct object_id peeled;
1893
1894                 if (ref_iterator_peel(current_ref_iter, &peeled))
1895                         return -1;
1896                 oidcpy(oid, &peeled);
1897                 return 0;
1898         }
1899
1900         if (refs_read_ref_full(refs, refname,
1901                                RESOLVE_REF_READING, &base, &flag))
1902                 return -1;
1903
1904         return peel_object(&base, oid);
1905 }
1906
1907 int peel_ref(const char *refname, struct object_id *oid)
1908 {
1909         return refs_peel_ref(get_main_ref_store(the_repository), refname, oid);
1910 }
1911
1912 int refs_create_symref(struct ref_store *refs,
1913                        const char *ref_target,
1914                        const char *refs_heads_master,
1915                        const char *logmsg)
1916 {
1917         char *msg;
1918         int retval;
1919
1920         msg = normalize_reflog_message(logmsg);
1921         retval = refs->be->create_symref(refs, ref_target, refs_heads_master,
1922                                          msg);
1923         free(msg);
1924         return retval;
1925 }
1926
1927 int create_symref(const char *ref_target, const char *refs_heads_master,
1928                   const char *logmsg)
1929 {
1930         return refs_create_symref(get_main_ref_store(the_repository), ref_target,
1931                                   refs_heads_master, logmsg);
1932 }
1933
1934 int ref_update_reject_duplicates(struct string_list *refnames,
1935                                  struct strbuf *err)
1936 {
1937         size_t i, n = refnames->nr;
1938
1939         assert(err);
1940
1941         for (i = 1; i < n; i++) {
1942                 int cmp = strcmp(refnames->items[i - 1].string,
1943                                  refnames->items[i].string);
1944
1945                 if (!cmp) {
1946                         strbuf_addf(err,
1947                                     _("multiple updates for ref '%s' not allowed"),
1948                                     refnames->items[i].string);
1949                         return 1;
1950                 } else if (cmp > 0) {
1951                         BUG("ref_update_reject_duplicates() received unsorted list");
1952                 }
1953         }
1954         return 0;
1955 }
1956
1957 static int run_transaction_hook(struct ref_transaction *transaction,
1958                                 const char *state)
1959 {
1960         struct child_process proc = CHILD_PROCESS_INIT;
1961         struct strbuf buf = STRBUF_INIT;
1962         const char *hook;
1963         int ret = 0, i;
1964
1965         hook = find_hook("reference-transaction");
1966         if (!hook)
1967                 return ret;
1968
1969         strvec_pushl(&proc.args, hook, state, NULL);
1970         proc.in = -1;
1971         proc.stdout_to_stderr = 1;
1972         proc.trace2_hook_name = "reference-transaction";
1973
1974         ret = start_command(&proc);
1975         if (ret)
1976                 return ret;
1977
1978         sigchain_push(SIGPIPE, SIG_IGN);
1979
1980         for (i = 0; i < transaction->nr; i++) {
1981                 struct ref_update *update = transaction->updates[i];
1982
1983                 strbuf_reset(&buf);
1984                 strbuf_addf(&buf, "%s %s %s\n",
1985                             oid_to_hex(&update->old_oid),
1986                             oid_to_hex(&update->new_oid),
1987                             update->refname);
1988
1989                 if (write_in_full(proc.in, buf.buf, buf.len) < 0) {
1990                         if (errno != EPIPE)
1991                                 ret = -1;
1992                         break;
1993                 }
1994         }
1995
1996         close(proc.in);
1997         sigchain_pop(SIGPIPE);
1998         strbuf_release(&buf);
1999
2000         ret |= finish_command(&proc);
2001         return ret;
2002 }
2003
2004 int ref_transaction_prepare(struct ref_transaction *transaction,
2005                             struct strbuf *err)
2006 {
2007         struct ref_store *refs = transaction->ref_store;
2008         int ret;
2009
2010         switch (transaction->state) {
2011         case REF_TRANSACTION_OPEN:
2012                 /* Good. */
2013                 break;
2014         case REF_TRANSACTION_PREPARED:
2015                 BUG("prepare called twice on reference transaction");
2016                 break;
2017         case REF_TRANSACTION_CLOSED:
2018                 BUG("prepare called on a closed reference transaction");
2019                 break;
2020         default:
2021                 BUG("unexpected reference transaction state");
2022                 break;
2023         }
2024
2025         if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
2026                 strbuf_addstr(err,
2027                               _("ref updates forbidden inside quarantine environment"));
2028                 return -1;
2029         }
2030
2031         ret = refs->be->transaction_prepare(refs, transaction, err);
2032         if (ret)
2033                 return ret;
2034
2035         ret = run_transaction_hook(transaction, "prepared");
2036         if (ret) {
2037                 ref_transaction_abort(transaction, err);
2038                 die(_("ref updates aborted by hook"));
2039         }
2040
2041         return 0;
2042 }
2043
2044 int ref_transaction_abort(struct ref_transaction *transaction,
2045                           struct strbuf *err)
2046 {
2047         struct ref_store *refs = transaction->ref_store;
2048         int ret = 0;
2049
2050         switch (transaction->state) {
2051         case REF_TRANSACTION_OPEN:
2052                 /* No need to abort explicitly. */
2053                 break;
2054         case REF_TRANSACTION_PREPARED:
2055                 ret = refs->be->transaction_abort(refs, transaction, err);
2056                 break;
2057         case REF_TRANSACTION_CLOSED:
2058                 BUG("abort called on a closed reference transaction");
2059                 break;
2060         default:
2061                 BUG("unexpected reference transaction state");
2062                 break;
2063         }
2064
2065         run_transaction_hook(transaction, "aborted");
2066
2067         ref_transaction_free(transaction);
2068         return ret;
2069 }
2070
2071 int ref_transaction_commit(struct ref_transaction *transaction,
2072                            struct strbuf *err)
2073 {
2074         struct ref_store *refs = transaction->ref_store;
2075         int ret;
2076
2077         switch (transaction->state) {
2078         case REF_TRANSACTION_OPEN:
2079                 /* Need to prepare first. */
2080                 ret = ref_transaction_prepare(transaction, err);
2081                 if (ret)
2082                         return ret;
2083                 break;
2084         case REF_TRANSACTION_PREPARED:
2085                 /* Fall through to finish. */
2086                 break;
2087         case REF_TRANSACTION_CLOSED:
2088                 BUG("commit called on a closed reference transaction");
2089                 break;
2090         default:
2091                 BUG("unexpected reference transaction state");
2092                 break;
2093         }
2094
2095         ret = refs->be->transaction_finish(refs, transaction, err);
2096         if (!ret)
2097                 run_transaction_hook(transaction, "committed");
2098         return ret;
2099 }
2100
2101 int refs_verify_refname_available(struct ref_store *refs,
2102                                   const char *refname,
2103                                   const struct string_list *extras,
2104                                   const struct string_list *skip,
2105                                   struct strbuf *err)
2106 {
2107         const char *slash;
2108         const char *extra_refname;
2109         struct strbuf dirname = STRBUF_INIT;
2110         struct strbuf referent = STRBUF_INIT;
2111         struct object_id oid;
2112         unsigned int type;
2113         struct ref_iterator *iter;
2114         int ok;
2115         int ret = -1;
2116
2117         /*
2118          * For the sake of comments in this function, suppose that
2119          * refname is "refs/foo/bar".
2120          */
2121
2122         assert(err);
2123
2124         strbuf_grow(&dirname, strlen(refname) + 1);
2125         for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
2126                 /* Expand dirname to the new prefix, not including the trailing slash: */
2127                 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
2128
2129                 /*
2130                  * We are still at a leading dir of the refname (e.g.,
2131                  * "refs/foo"; if there is a reference with that name,
2132                  * it is a conflict, *unless* it is in skip.
2133                  */
2134                 if (skip && string_list_has_string(skip, dirname.buf))
2135                         continue;
2136
2137                 if (!refs_read_raw_ref(refs, dirname.buf, &oid, &referent, &type)) {
2138                         strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
2139                                     dirname.buf, refname);
2140                         goto cleanup;
2141                 }
2142
2143                 if (extras && string_list_has_string(extras, dirname.buf)) {
2144                         strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
2145                                     refname, dirname.buf);
2146                         goto cleanup;
2147                 }
2148         }
2149
2150         /*
2151          * We are at the leaf of our refname (e.g., "refs/foo/bar").
2152          * There is no point in searching for a reference with that
2153          * name, because a refname isn't considered to conflict with
2154          * itself. But we still need to check for references whose
2155          * names are in the "refs/foo/bar/" namespace, because they
2156          * *do* conflict.
2157          */
2158         strbuf_addstr(&dirname, refname + dirname.len);
2159         strbuf_addch(&dirname, '/');
2160
2161         iter = refs_ref_iterator_begin(refs, dirname.buf, 0,
2162                                        DO_FOR_EACH_INCLUDE_BROKEN);
2163         while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
2164                 if (skip &&
2165                     string_list_has_string(skip, iter->refname))
2166                         continue;
2167
2168                 strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
2169                             iter->refname, refname);
2170                 ref_iterator_abort(iter);
2171                 goto cleanup;
2172         }
2173
2174         if (ok != ITER_DONE)
2175                 BUG("error while iterating over references");
2176
2177         extra_refname = find_descendant_ref(dirname.buf, extras, skip);
2178         if (extra_refname)
2179                 strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
2180                             refname, extra_refname);
2181         else
2182                 ret = 0;
2183
2184 cleanup:
2185         strbuf_release(&referent);
2186         strbuf_release(&dirname);
2187         return ret;
2188 }
2189
2190 int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2191 {
2192         struct ref_iterator *iter;
2193         struct do_for_each_ref_help hp = { fn, cb_data };
2194
2195         iter = refs->be->reflog_iterator_begin(refs);
2196
2197         return do_for_each_repo_ref_iterator(the_repository, iter,
2198                                              do_for_each_ref_helper, &hp);
2199 }
2200
2201 int for_each_reflog(each_ref_fn fn, void *cb_data)
2202 {
2203         return refs_for_each_reflog(get_main_ref_store(the_repository), fn, cb_data);
2204 }
2205
2206 int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
2207                                      const char *refname,
2208                                      each_reflog_ent_fn fn,
2209                                      void *cb_data)
2210 {
2211         return refs->be->for_each_reflog_ent_reverse(refs, refname,
2212                                                      fn, cb_data);
2213 }
2214
2215 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
2216                                 void *cb_data)
2217 {
2218         return refs_for_each_reflog_ent_reverse(get_main_ref_store(the_repository),
2219                                                 refname, fn, cb_data);
2220 }
2221
2222 int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
2223                              each_reflog_ent_fn fn, void *cb_data)
2224 {
2225         return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
2226 }
2227
2228 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
2229                         void *cb_data)
2230 {
2231         return refs_for_each_reflog_ent(get_main_ref_store(the_repository), refname,
2232                                         fn, cb_data);
2233 }
2234
2235 int refs_reflog_exists(struct ref_store *refs, const char *refname)
2236 {
2237         return refs->be->reflog_exists(refs, refname);
2238 }
2239
2240 int reflog_exists(const char *refname)
2241 {
2242         return refs_reflog_exists(get_main_ref_store(the_repository), refname);
2243 }
2244
2245 int refs_create_reflog(struct ref_store *refs, const char *refname,
2246                        int force_create, struct strbuf *err)
2247 {
2248         return refs->be->create_reflog(refs, refname, force_create, err);
2249 }
2250
2251 int safe_create_reflog(const char *refname, int force_create,
2252                        struct strbuf *err)
2253 {
2254         return refs_create_reflog(get_main_ref_store(the_repository), refname,
2255                                   force_create, err);
2256 }
2257
2258 int refs_delete_reflog(struct ref_store *refs, const char *refname)
2259 {
2260         return refs->be->delete_reflog(refs, refname);
2261 }
2262
2263 int delete_reflog(const char *refname)
2264 {
2265         return refs_delete_reflog(get_main_ref_store(the_repository), refname);
2266 }
2267
2268 int refs_reflog_expire(struct ref_store *refs,
2269                        const char *refname, const struct object_id *oid,
2270                        unsigned int flags,
2271                        reflog_expiry_prepare_fn prepare_fn,
2272                        reflog_expiry_should_prune_fn should_prune_fn,
2273                        reflog_expiry_cleanup_fn cleanup_fn,
2274                        void *policy_cb_data)
2275 {
2276         return refs->be->reflog_expire(refs, refname, oid, flags,
2277                                        prepare_fn, should_prune_fn,
2278                                        cleanup_fn, policy_cb_data);
2279 }
2280
2281 int reflog_expire(const char *refname, const struct object_id *oid,
2282                   unsigned int flags,
2283                   reflog_expiry_prepare_fn prepare_fn,
2284                   reflog_expiry_should_prune_fn should_prune_fn,
2285                   reflog_expiry_cleanup_fn cleanup_fn,
2286                   void *policy_cb_data)
2287 {
2288         return refs_reflog_expire(get_main_ref_store(the_repository),
2289                                   refname, oid, flags,
2290                                   prepare_fn, should_prune_fn,
2291                                   cleanup_fn, policy_cb_data);
2292 }
2293
2294 int initial_ref_transaction_commit(struct ref_transaction *transaction,
2295                                    struct strbuf *err)
2296 {
2297         struct ref_store *refs = transaction->ref_store;
2298
2299         return refs->be->initial_transaction_commit(refs, transaction, err);
2300 }
2301
2302 int refs_delete_refs(struct ref_store *refs, const char *logmsg,
2303                      struct string_list *refnames, unsigned int flags)
2304 {
2305         char *msg;
2306         int retval;
2307
2308         msg = normalize_reflog_message(logmsg);
2309         retval = refs->be->delete_refs(refs, msg, refnames, flags);
2310         free(msg);
2311         return retval;
2312 }
2313
2314 int delete_refs(const char *msg, struct string_list *refnames,
2315                 unsigned int flags)
2316 {
2317         return refs_delete_refs(get_main_ref_store(the_repository), msg, refnames, flags);
2318 }
2319
2320 int refs_rename_ref(struct ref_store *refs, const char *oldref,
2321                     const char *newref, const char *logmsg)
2322 {
2323         char *msg;
2324         int retval;
2325
2326         msg = normalize_reflog_message(logmsg);
2327         retval = refs->be->rename_ref(refs, oldref, newref, msg);
2328         free(msg);
2329         return retval;
2330 }
2331
2332 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
2333 {
2334         return refs_rename_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
2335 }
2336
2337 int refs_copy_existing_ref(struct ref_store *refs, const char *oldref,
2338                     const char *newref, const char *logmsg)
2339 {
2340         char *msg;
2341         int retval;
2342
2343         msg = normalize_reflog_message(logmsg);
2344         retval = refs->be->copy_ref(refs, oldref, newref, msg);
2345         free(msg);
2346         return retval;
2347 }
2348
2349 int copy_existing_ref(const char *oldref, const char *newref, const char *logmsg)
2350 {
2351         return refs_copy_existing_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
2352 }