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
 571         if (repo_config_get_string(r, config_key, &ret) < 0)
 572                 die(_("could not retrieve `%s`"), config_display_key);
 573
 574         if (!ret)
 575                 ret = xstrdup("master");
 576
 577         full_ref = xstrfmt("refs/heads/%s", ret);
 578         if (check_refname_format(full_ref, 0))
 579                 die(_("invalid branch name: %s = %s"), config_display_key, ret);
 580         free(full_ref);
 581
 582         return ret;
 583 }
 584
 585 const char *git_default_branch_name(void)
 586 {
 587         static char *ret;
 588
 589         if (!ret)
 590                 ret = repo_default_branch_name(the_repository);
 591
 592         return ret;
 593 }
 594
 595 /*
 596  * *string and *len will only be substituted, and *string returned (for
 597  * later free()ing) if the string passed in is a magic short-hand form
 598  * to name a branch.
 599  */
 600 static char *substitute_branch_name(struct repository *r,
 601                                     const char **string, int *len,
 602                                     int nonfatal_dangling_mark)
 603 {
 604         struct strbuf buf = STRBUF_INIT;
 605         struct interpret_branch_name_options options = {
 606                 .nonfatal_dangling_mark = nonfatal_dangling_mark
 607         };
 608         int ret = repo_interpret_branch_name(r, *string, *len, &buf, &options);
 609
 610         if (ret == *len) {
 611                 size_t size;
 612                 *string = strbuf_detach(&buf, &size);
 613                 *len = size;
 614                 return (char *)*string;
 615         }
 616
 617         return NULL;
 618 }
 619
 620 int repo_dwim_ref(struct repository *r, const char *str, int len,
 621                   struct object_id *oid, char **ref, int nonfatal_dangling_mark)
 622 {
 623         char *last_branch = substitute_branch_name(r, &str, &len,
 624                                                    nonfatal_dangling_mark);
 625         int   refs_found  = expand_ref(r, str, len, oid, ref);
 626         free(last_branch);
 627         return refs_found;
 628 }
 629
 630 int expand_ref(struct repository *repo, const char *str, int len,
 631                struct object_id *oid, char **ref)
 632 {
 633         const char **p, *r;
 634         int refs_found = 0;
 635         struct strbuf fullref = STRBUF_INIT;
 636
 637         *ref = NULL;
 638         for (p = ref_rev_parse_rules; *p; p++) {
 639                 struct object_id oid_from_ref;
 640                 struct object_id *this_result;
 641                 int flag;
 642
 643                 this_result = refs_found ? &oid_from_ref : oid;
 644                 strbuf_reset(&fullref);
 645                 strbuf_addf(&fullref, *p, len, str);
 646                 r = refs_resolve_ref_unsafe(get_main_ref_store(repo),
 647                                             fullref.buf, RESOLVE_REF_READING,
 648                                             this_result, &flag);
 649                 if (r) {
 650                         if (!refs_found++)
 651                                 *ref = xstrdup(r);
 652                         if (!warn_ambiguous_refs)
 653                                 break;
 654                 } else if ((flag & REF_ISSYMREF) && strcmp(fullref.buf, "HEAD")) {
 655                         warning(_("ignoring dangling symref %s"), fullref.buf);
 656                 } else if ((flag & REF_ISBROKEN) && strchr(fullref.buf, '/')) {
 657                         warning(_("ignoring broken ref %s"), fullref.buf);
 658                 }
 659         }
 660         strbuf_release(&fullref);
 661         return refs_found;
 662 }
 663
 664 int repo_dwim_log(struct repository *r, const char *str, int len,
 665                   struct object_id *oid, char **log)
 666 {
 667         struct ref_store *refs = get_main_ref_store(r);
 668         char *last_branch = substitute_branch_name(r, &str, &len, 0);
 669         const char **p;
 670         int logs_found = 0;
 671         struct strbuf path = STRBUF_INIT;
 672
 673         *log = NULL;
 674         for (p = ref_rev_parse_rules; *p; p++) {
 675                 struct object_id hash;
 676                 const char *ref, *it;
 677
 678                 strbuf_reset(&path);
 679                 strbuf_addf(&path, *p, len, str);
 680                 ref = refs_resolve_ref_unsafe(refs, path.buf,
 681                                               RESOLVE_REF_READING,
 682                                               &hash, NULL);
 683                 if (!ref)
 684                         continue;
 685                 if (refs_reflog_exists(refs, path.buf))
 686                         it = path.buf;
 687                 else if (strcmp(ref, path.buf) &&
 688                          refs_reflog_exists(refs, ref))
 689                         it = ref;
 690                 else
 691                         continue;
 692                 if (!logs_found++) {
 693                         *log = xstrdup(it);
 694                         oidcpy(oid, &hash);
 695                 }
 696                 if (!warn_ambiguous_refs)
 697                         break;
 698         }
 699         strbuf_release(&path);
 700         free(last_branch);
 701         return logs_found;
 702 }
 703
 704 int dwim_log(const char *str, int len, struct object_id *oid, char **log)
 705 {
 706         return repo_dwim_log(the_repository, str, len, oid, log);
 707 }
 708
 709 static int is_per_worktree_ref(const char *refname)
 710 {
 711         return starts_with(refname, "refs/worktree/") ||
 712                starts_with(refname, "refs/bisect/") ||
 713                starts_with(refname, "refs/rewritten/");
 714 }
 715
 716 static int is_pseudoref_syntax(const char *refname)
 717 {
 718         const char *c;
 719
 720         for (c = refname; *c; c++) {
 721                 if (!isupper(*c) && *c != '-' && *c != '_')
 722                         return 0;
 723         }
 724
 725         return 1;
 726 }
 727
 728 static int is_main_pseudoref_syntax(const char *refname)
 729 {
 730         return skip_prefix(refname, "main-worktree/", &refname) &&
 731                 *refname &&
 732                 is_pseudoref_syntax(refname);
 733 }
 734
 735 static int is_other_pseudoref_syntax(const char *refname)
 736 {
 737         if (!skip_prefix(refname, "worktrees/", &refname))
 738                 return 0;
 739         refname = strchr(refname, '/');
 740         if (!refname || !refname[1])
 741                 return 0;
 742         return is_pseudoref_syntax(refname + 1);
 743 }
 744
 745 enum ref_type ref_type(const char *refname)
 746 {
 747         if (is_per_worktree_ref(refname))
 748                 return REF_TYPE_PER_WORKTREE;
 749         if (is_pseudoref_syntax(refname))
 750                 return REF_TYPE_PSEUDOREF;
 751         if (is_main_pseudoref_syntax(refname))
 752                 return REF_TYPE_MAIN_PSEUDOREF;
 753         if (is_other_pseudoref_syntax(refname))
 754                 return REF_TYPE_OTHER_PSEUDOREF;
 755         return REF_TYPE_NORMAL;
 756 }
 757
 758 long get_files_ref_lock_timeout_ms(void)
 759 {
 760         static int configured = 0;
 761
 762         /* The default timeout is 100 ms: */
 763         static int timeout_ms = 100;
 764
 765         if (!configured) {
 766                 git_config_get_int("core.filesreflocktimeout", &timeout_ms);
 767                 configured = 1;
 768         }
 769
 770         return timeout_ms;
 771 }
 772
 773 int refs_delete_ref(struct ref_store *refs, const char *msg,
 774                     const char *refname,
 775                     const struct object_id *old_oid,
 776                     unsigned int flags)
 777 {
 778         struct ref_transaction *transaction;
 779         struct strbuf err = STRBUF_INIT;
 780
 781         transaction = ref_store_transaction_begin(refs, &err);
 782         if (!transaction ||
 783             ref_transaction_delete(transaction, refname, old_oid,
 784                                    flags, msg, &err) ||
 785             ref_transaction_commit(transaction, &err)) {
 786                 error("%s", err.buf);
 787                 ref_transaction_free(transaction);
 788                 strbuf_release(&err);
 789                 return 1;
 790         }
 791         ref_transaction_free(transaction);
 792         strbuf_release(&err);
 793         return 0;
 794 }
 795
 796 int delete_ref(const char *msg, const char *refname,
 797                const struct object_id *old_oid, unsigned int flags)
 798 {
 799         return refs_delete_ref(get_main_ref_store(the_repository), msg, refname,
 800                                old_oid, flags);
 801 }
 802
 803 static void copy_reflog_msg(struct strbuf *sb, const char *msg)
 804 {
 805         char c;
 806         int wasspace = 1;
 807
 808         while ((c = *msg++)) {
 809                 if (wasspace && isspace(c))
 810                         continue;
 811                 wasspace = isspace(c);
 812                 if (wasspace)
 813                         c = ' ';
 814                 strbuf_addch(sb, c);
 815         }
 816         strbuf_rtrim(sb);
 817 }
 818
 819 static char *normalize_reflog_message(const char *msg)
 820 {
 821         struct strbuf sb = STRBUF_INIT;
 822
 823         if (msg && *msg)
 824                 copy_reflog_msg(&sb, msg);
 825         return strbuf_detach(&sb, NULL);
 826 }
 827
 828 int should_autocreate_reflog(const char *refname)
 829 {
 830         switch (log_all_ref_updates) {
 831         case LOG_REFS_ALWAYS:
 832                 return 1;
 833         case LOG_REFS_NORMAL:
 834                 return starts_with(refname, "refs/heads/") ||
 835                         starts_with(refname, "refs/remotes/") ||
 836                         starts_with(refname, "refs/notes/") ||
 837                         !strcmp(refname, "HEAD");
 838         default:
 839                 return 0;
 840         }
 841 }
 842
 843 int is_branch(const char *refname)
 844 {
 845         return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
 846 }
 847
 848 struct read_ref_at_cb {
 849         const char *refname;
 850         timestamp_t at_time;
 851         int cnt;
 852         int reccnt;
 853         struct object_id *oid;
 854         int found_it;
 855
 856         struct object_id ooid;
 857         struct object_id noid;
 858         int tz;
 859         timestamp_t date;
 860         char **msg;
 861         timestamp_t *cutoff_time;
 862         int *cutoff_tz;
 863         int *cutoff_cnt;
 864 };
 865
 866 static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
 867                 const char *email, timestamp_t timestamp, int tz,
 868                 const char *message, void *cb_data)
 869 {
 870         struct read_ref_at_cb *cb = cb_data;
 871
 872         cb->reccnt++;
 873         cb->tz = tz;
 874         cb->date = timestamp;
 875
 876         if (timestamp <= cb->at_time || cb->cnt == 0) {
 877                 if (cb->msg)
 878                         *cb->msg = xstrdup(message);
 879                 if (cb->cutoff_time)
 880                         *cb->cutoff_time = timestamp;
 881                 if (cb->cutoff_tz)
 882                         *cb->cutoff_tz = tz;
 883                 if (cb->cutoff_cnt)
 884                         *cb->cutoff_cnt = cb->reccnt - 1;
 885                 /*
 886                  * we have not yet updated cb->[n|o]oid so they still
 887                  * hold the values for the previous record.
 888                  */
 889                 if (!is_null_oid(&cb->ooid)) {
 890                         oidcpy(cb->oid, noid);
 891                         if (!oideq(&cb->ooid, noid))
 892                                 warning(_("log for ref %s has gap after %s"),
 893                                         cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
 894                 }
 895                 else if (cb->date == cb->at_time)
 896                         oidcpy(cb->oid, noid);
 897                 else if (!oideq(noid, cb->oid))
 898                         warning(_("log for ref %s unexpectedly ended on %s"),
 899                                 cb->refname, show_date(cb->date, cb->tz,
 900                                                        DATE_MODE(RFC2822)));
 901                 oidcpy(&cb->ooid, ooid);
 902                 oidcpy(&cb->noid, noid);
 903                 cb->found_it = 1;
 904                 return 1;
 905         }
 906         oidcpy(&cb->ooid, ooid);
 907         oidcpy(&cb->noid, noid);
 908         if (cb->cnt > 0)
 909                 cb->cnt--;
 910         return 0;
 911 }
 912
 913 static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
 914                                   const char *email, timestamp_t timestamp,
 915                                   int tz, const char *message, void *cb_data)
 916 {
 917         struct read_ref_at_cb *cb = cb_data;
 918
 919         if (cb->msg)
 920                 *cb->msg = xstrdup(message);
 921         if (cb->cutoff_time)
 922                 *cb->cutoff_time = timestamp;
 923         if (cb->cutoff_tz)
 924                 *cb->cutoff_tz = tz;
 925         if (cb->cutoff_cnt)
 926                 *cb->cutoff_cnt = cb->reccnt;
 927         oidcpy(cb->oid, ooid);
 928         if (is_null_oid(cb->oid))
 929                 oidcpy(cb->oid, noid);
 930         /* We just want the first entry */
 931         return 1;
 932 }
 933
 934 int read_ref_at(struct ref_store *refs, const char *refname,
 935                 unsigned int flags, timestamp_t at_time, int cnt,
 936                 struct object_id *oid, char **msg,
 937                 timestamp_t *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
 938 {
 939         struct read_ref_at_cb cb;
 940
 941         memset(&cb, 0, sizeof(cb));
 942         cb.refname = refname;
 943         cb.at_time = at_time;
 944         cb.cnt = cnt;
 945         cb.msg = msg;
 946         cb.cutoff_time = cutoff_time;
 947         cb.cutoff_tz = cutoff_tz;
 948         cb.cutoff_cnt = cutoff_cnt;
 949         cb.oid = oid;
 950
 951         refs_for_each_reflog_ent_reverse(refs, refname, read_ref_at_ent, &cb);
 952
 953         if (!cb.reccnt) {
 954                 if (flags & GET_OID_QUIETLY)
 955                         exit(128);
 956                 else
 957                         die(_("log for %s is empty"), refname);
 958         }
 959         if (cb.found_it)
 960                 return 0;
 961
 962         refs_for_each_reflog_ent(refs, refname, read_ref_at_ent_oldest, &cb);
 963
 964         return 1;
 965 }
 966
 967 struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
 968                                                     struct strbuf *err)
 969 {
 970         struct ref_transaction *tr;
 971         assert(err);
 972
 973         tr = xcalloc(1, sizeof(struct ref_transaction));
 974         tr->ref_store = refs;
 975         return tr;
 976 }
 977
 978 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 979 {
 980         return ref_store_transaction_begin(get_main_ref_store(the_repository), err);
 981 }
 982
 983 void ref_transaction_free(struct ref_transaction *transaction)
 984 {
 985         size_t i;
 986
 987         if (!transaction)
 988                 return;
 989
 990         switch (transaction->state) {
 991         case REF_TRANSACTION_OPEN:
 992         case REF_TRANSACTION_CLOSED:
 993                 /* OK */
 994                 break;
 995         case REF_TRANSACTION_PREPARED:
 996                 BUG("free called on a prepared reference transaction");
 997                 break;
 998         default:
 999                 BUG("unexpected reference transaction state");
1000                 break;
1001         }
1002
1003         for (i = 0; i < transaction->nr; i++) {
1004                 free(transaction->updates[i]->msg);
1005                 free(transaction->updates[i]);
1006         }
1007         free(transaction->updates);
1008         free(transaction);
1009 }
1010
1011 struct ref_update *ref_transaction_add_update(
1012                 struct ref_transaction *transaction,
1013                 const char *refname, unsigned int flags,
1014                 const struct object_id *new_oid,
1015                 const struct object_id *old_oid,
1016                 const char *msg)
1017 {
1018         struct ref_update *update;
1019
1020         if (transaction->state != REF_TRANSACTION_OPEN)
1021                 BUG("update called for transaction that is not open");
1022
1023         FLEX_ALLOC_STR(update, refname, refname);
1024         ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
1025         transaction->updates[transaction->nr++] = update;
1026
1027         update->flags = flags;
1028
1029         if (flags & REF_HAVE_NEW)
1030                 oidcpy(&update->new_oid, new_oid);
1031         if (flags & REF_HAVE_OLD)
1032                 oidcpy(&update->old_oid, old_oid);
1033         update->msg = normalize_reflog_message(msg);
1034         return update;
1035 }
1036
1037 int ref_transaction_update(struct ref_transaction *transaction,
1038                            const char *refname,
1039                            const struct object_id *new_oid,
1040                            const struct object_id *old_oid,
1041                            unsigned int flags, const char *msg,
1042                            struct strbuf *err)
1043 {
1044         assert(err);
1045
1046         if ((new_oid && !is_null_oid(new_oid)) ?
1047             check_refname_format(refname, REFNAME_ALLOW_ONELEVEL) :
1048             !refname_is_safe(refname)) {
1049                 strbuf_addf(err, _("refusing to update ref with bad name '%s'"),
1050                             refname);
1051                 return -1;
1052         }
1053
1054         if (flags & ~REF_TRANSACTION_UPDATE_ALLOWED_FLAGS)
1055                 BUG("illegal flags 0x%x passed to ref_transaction_update()", flags);
1056
1057         flags |= (new_oid ? REF_HAVE_NEW : 0) | (old_oid ? REF_HAVE_OLD : 0);
1058
1059         ref_transaction_add_update(transaction, refname, flags,
1060                                    new_oid, old_oid, msg);
1061         return 0;
1062 }
1063
1064 int ref_transaction_create(struct ref_transaction *transaction,
1065                            const char *refname,
1066                            const struct object_id *new_oid,
1067                            unsigned int flags, const char *msg,
1068                            struct strbuf *err)
1069 {
1070         if (!new_oid || is_null_oid(new_oid))
1071                 BUG("create called without valid new_oid");
1072         return ref_transaction_update(transaction, refname, new_oid,
1073                                       &null_oid, flags, msg, err);
1074 }
1075
1076 int ref_transaction_delete(struct ref_transaction *transaction,
1077                            const char *refname,
1078                            const struct object_id *old_oid,
1079                            unsigned int flags, const char *msg,
1080                            struct strbuf *err)
1081 {
1082         if (old_oid && is_null_oid(old_oid))
1083                 BUG("delete called with old_oid set to zeros");
1084         return ref_transaction_update(transaction, refname,
1085                                       &null_oid, old_oid,
1086                                       flags, msg, err);
1087 }
1088
1089 int ref_transaction_verify(struct ref_transaction *transaction,
1090                            const char *refname,
1091                            const struct object_id *old_oid,
1092                            unsigned int flags,
1093                            struct strbuf *err)
1094 {
1095         if (!old_oid)
1096                 BUG("verify called with old_oid set to NULL");
1097         return ref_transaction_update(transaction, refname,
1098                                       NULL, old_oid,
1099                                       flags, NULL, err);
1100 }
1101
1102 int refs_update_ref(struct ref_store *refs, const char *msg,
1103                     const char *refname, const struct object_id *new_oid,
1104                     const struct object_id *old_oid, unsigned int flags,
1105                     enum action_on_err onerr)
1106 {
1107         struct ref_transaction *t = NULL;
1108         struct strbuf err = STRBUF_INIT;
1109         int ret = 0;
1110
1111         t = ref_store_transaction_begin(refs, &err);
1112         if (!t ||
1113             ref_transaction_update(t, refname, new_oid, old_oid, flags, msg,
1114                                    &err) ||
1115             ref_transaction_commit(t, &err)) {
1116                 ret = 1;
1117                 ref_transaction_free(t);
1118         }
1119         if (ret) {
1120                 const char *str = _("update_ref failed for ref '%s': %s");
1121
1122                 switch (onerr) {
1123                 case UPDATE_REFS_MSG_ON_ERR:
1124                         error(str, refname, err.buf);
1125                         break;
1126                 case UPDATE_REFS_DIE_ON_ERR:
1127                         die(str, refname, err.buf);
1128                         break;
1129                 case UPDATE_REFS_QUIET_ON_ERR:
1130                         break;
1131                 }
1132                 strbuf_release(&err);
1133                 return 1;
1134         }
1135         strbuf_release(&err);
1136         if (t)
1137                 ref_transaction_free(t);
1138         return 0;
1139 }
1140
1141 int update_ref(const char *msg, const char *refname,
1142                const struct object_id *new_oid,
1143                const struct object_id *old_oid,
1144                unsigned int flags, enum action_on_err onerr)
1145 {
1146         return refs_update_ref(get_main_ref_store(the_repository), msg, refname, new_oid,
1147                                old_oid, flags, onerr);
1148 }
1149
1150 char *refs_shorten_unambiguous_ref(struct ref_store *refs,
1151                                    const char *refname, int strict)
1152 {
1153         int i;
1154         static char **scanf_fmts;
1155         static int nr_rules;
1156         char *short_name;
1157         struct strbuf resolved_buf = STRBUF_INIT;
1158
1159         if (!nr_rules) {
1160                 /*
1161                  * Pre-generate scanf formats from ref_rev_parse_rules[].
1162                  * Generate a format suitable for scanf from a
1163                  * ref_rev_parse_rules rule by interpolating "%s" at the
1164                  * location of the "%.*s".
1165                  */
1166                 size_t total_len = 0;
1167                 size_t offset = 0;
1168
1169                 /* the rule list is NULL terminated, count them first */
1170                 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
1171                         /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
1172                         total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
1173
1174                 scanf_fmts = xmalloc(st_add(st_mult(sizeof(char *), nr_rules), total_len));
1175
1176                 offset = 0;
1177                 for (i = 0; i < nr_rules; i++) {
1178                         assert(offset < total_len);
1179                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
1180                         offset += xsnprintf(scanf_fmts[i], total_len - offset,
1181                                             ref_rev_parse_rules[i], 2, "%s") + 1;
1182                 }
1183         }
1184
1185         /* bail out if there are no rules */
1186         if (!nr_rules)
1187                 return xstrdup(refname);
1188
1189         /* buffer for scanf result, at most refname must fit */
1190         short_name = xstrdup(refname);
1191
1192         /* skip first rule, it will always match */
1193         for (i = nr_rules - 1; i > 0 ; --i) {
1194                 int j;
1195                 int rules_to_fail = i;
1196                 int short_name_len;
1197
1198                 if (1 != sscanf(refname, scanf_fmts[i], short_name))
1199                         continue;
1200
1201                 short_name_len = strlen(short_name);
1202
1203                 /*
1204                  * in strict mode, all (except the matched one) rules
1205                  * must fail to resolve to a valid non-ambiguous ref
1206                  */
1207                 if (strict)
1208                         rules_to_fail = nr_rules;
1209
1210                 /*
1211                  * check if the short name resolves to a valid ref,
1212                  * but use only rules prior to the matched one
1213                  */
1214                 for (j = 0; j < rules_to_fail; j++) {
1215                         const char *rule = ref_rev_parse_rules[j];
1216
1217                         /* skip matched rule */
1218                         if (i == j)
1219                                 continue;
1220
1221                         /*
1222                          * the short name is ambiguous, if it resolves
1223                          * (with this previous rule) to a valid ref
1224                          * read_ref() returns 0 on success
1225                          */
1226                         strbuf_reset(&resolved_buf);
1227                         strbuf_addf(&resolved_buf, rule,
1228                                     short_name_len, short_name);
1229                         if (refs_ref_exists(refs, resolved_buf.buf))
1230                                 break;
1231                 }
1232
1233                 /*
1234                  * short name is non-ambiguous if all previous rules
1235                  * haven't resolved to a valid ref
1236                  */
1237                 if (j == rules_to_fail) {
1238                         strbuf_release(&resolved_buf);
1239                         return short_name;
1240                 }
1241         }
1242
1243         strbuf_release(&resolved_buf);
1244         free(short_name);
1245         return xstrdup(refname);
1246 }
1247
1248 char *shorten_unambiguous_ref(const char *refname, int strict)
1249 {
1250         return refs_shorten_unambiguous_ref(get_main_ref_store(the_repository),
1251                                             refname, strict);
1252 }
1253
1254 static struct string_list *hide_refs;
1255
1256 int parse_hide_refs_config(const char *var, const char *value, const char *section)
1257 {
1258         const char *key;
1259         if (!strcmp("transfer.hiderefs", var) ||
1260             (!parse_config_key(var, section, NULL, NULL, &key) &&
1261              !strcmp(key, "hiderefs"))) {
1262                 char *ref;
1263                 int len;
1264
1265                 if (!value)
1266                         return config_error_nonbool(var);
1267                 ref = xstrdup(value);
1268                 len = strlen(ref);
1269                 while (len && ref[len - 1] == '/')
1270                         ref[--len] = '\0';
1271                 if (!hide_refs) {
1272                         hide_refs = xcalloc(1, sizeof(*hide_refs));
1273                         hide_refs->strdup_strings = 1;
1274                 }
1275                 string_list_append(hide_refs, ref);
1276         }
1277         return 0;
1278 }
1279
1280 int ref_is_hidden(const char *refname, const char *refname_full)
1281 {
1282         int i;
1283
1284         if (!hide_refs)
1285                 return 0;
1286         for (i = hide_refs->nr - 1; i >= 0; i--) {
1287                 const char *match = hide_refs->items[i].string;
1288                 const char *subject;
1289                 int neg = 0;
1290                 const char *p;
1291
1292                 if (*match == '!') {
1293                         neg = 1;
1294                         match++;
1295                 }
1296
1297                 if (*match == '^') {
1298                         subject = refname_full;
1299                         match++;
1300                 } else {
1301                         subject = refname;
1302                 }
1303
1304                 /* refname can be NULL when namespaces are used. */
1305                 if (subject &&
1306                     skip_prefix(subject, match, &p) &&
1307                     (!*p || *p == '/'))
1308                         return !neg;
1309         }
1310         return 0;
1311 }
1312
1313 const char *find_descendant_ref(const char *dirname,
1314                                 const struct string_list *extras,
1315                                 const struct string_list *skip)
1316 {
1317         int pos;
1318
1319         if (!extras)
1320                 return NULL;
1321
1322         /*
1323          * Look at the place where dirname would be inserted into
1324          * extras. If there is an entry at that position that starts
1325          * with dirname (remember, dirname includes the trailing
1326          * slash) and is not in skip, then we have a conflict.
1327          */
1328         for (pos = string_list_find_insert_index(extras, dirname, 0);
1329              pos < extras->nr; pos++) {
1330                 const char *extra_refname = extras->items[pos].string;
1331
1332                 if (!starts_with(extra_refname, dirname))
1333                         break;
1334
1335                 if (!skip || !string_list_has_string(skip, extra_refname))
1336                         return extra_refname;
1337         }
1338         return NULL;
1339 }
1340
1341 int refs_rename_ref_available(struct ref_store *refs,
1342                               const char *old_refname,
1343                               const char *new_refname)
1344 {
1345         struct string_list skip = STRING_LIST_INIT_NODUP;
1346         struct strbuf err = STRBUF_INIT;
1347         int ok;
1348
1349         string_list_insert(&skip, old_refname);
1350         ok = !refs_verify_refname_available(refs, new_refname,
1351                                             NULL, &skip, &err);
1352         if (!ok)
1353                 error("%s", err.buf);
1354
1355         string_list_clear(&skip, 0);
1356         strbuf_release(&err);
1357         return ok;
1358 }
1359
1360 int refs_head_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1361 {
1362         struct object_id oid;
1363         int flag;
1364
1365         if (!refs_read_ref_full(refs, "HEAD", RESOLVE_REF_READING,
1366                                 &oid, &flag))
1367                 return fn("HEAD", &oid, flag, cb_data);
1368
1369         return 0;
1370 }
1371
1372 int head_ref(each_ref_fn fn, void *cb_data)
1373 {
1374         return refs_head_ref(get_main_ref_store(the_repository), fn, cb_data);
1375 }
1376
1377 struct ref_iterator *refs_ref_iterator_begin(
1378                 struct ref_store *refs,
1379                 const char *prefix, int trim, int flags)
1380 {
1381         struct ref_iterator *iter;
1382
1383         if (ref_paranoia < 0)
1384                 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1385         if (ref_paranoia)
1386                 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1387
1388         iter = refs->be->iterator_begin(refs, prefix, flags);
1389
1390         /*
1391          * `iterator_begin()` already takes care of prefix, but we
1392          * might need to do some trimming:
1393          */
1394         if (trim)
1395                 iter = prefix_ref_iterator_begin(iter, "", trim);
1396
1397         /* Sanity check for subclasses: */
1398         if (!iter->ordered)
1399                 BUG("reference iterator is not ordered");
1400
1401         return iter;
1402 }
1403
1404 /*
1405  * Call fn for each reference in the specified submodule for which the
1406  * refname begins with prefix. If trim is non-zero, then trim that
1407  * many characters off the beginning of each refname before passing
1408  * the refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to
1409  * include broken references in the iteration. If fn ever returns a
1410  * non-zero value, stop the iteration and return that value;
1411  * otherwise, return 0.
1412  */
1413 static int do_for_each_repo_ref(struct repository *r, const char *prefix,
1414                                 each_repo_ref_fn fn, int trim, int flags,
1415                                 void *cb_data)
1416 {
1417         struct ref_iterator *iter;
1418         struct ref_store *refs = get_main_ref_store(r);
1419
1420         if (!refs)
1421                 return 0;
1422
1423         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1424
1425         return do_for_each_repo_ref_iterator(r, iter, fn, cb_data);
1426 }
1427
1428 struct do_for_each_ref_help {
1429         each_ref_fn *fn;
1430         void *cb_data;
1431 };
1432
1433 static int do_for_each_ref_helper(struct repository *r,
1434                                   const char *refname,
1435                                   const struct object_id *oid,
1436                                   int flags,
1437                                   void *cb_data)
1438 {
1439         struct do_for_each_ref_help *hp = cb_data;
1440
1441         return hp->fn(refname, oid, flags, hp->cb_data);
1442 }
1443
1444 static int do_for_each_ref(struct ref_store *refs, const char *prefix,
1445                            each_ref_fn fn, int trim, int flags, void *cb_data)
1446 {
1447         struct ref_iterator *iter;
1448         struct do_for_each_ref_help hp = { fn, cb_data };
1449
1450         if (!refs)
1451                 return 0;
1452
1453         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1454
1455         return do_for_each_repo_ref_iterator(the_repository, iter,
1456                                         do_for_each_ref_helper, &hp);
1457 }
1458
1459 int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1460 {
1461         return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
1462 }
1463
1464 int for_each_ref(each_ref_fn fn, void *cb_data)
1465 {
1466         return refs_for_each_ref(get_main_ref_store(the_repository), fn, cb_data);
1467 }
1468
1469 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
1470                          each_ref_fn fn, void *cb_data)
1471 {
1472         return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
1473 }
1474
1475 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1476 {
1477         return refs_for_each_ref_in(get_main_ref_store(the_repository), prefix, fn, cb_data);
1478 }
1479
1480 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1481 {
1482         unsigned int flag = 0;
1483
1484         if (broken)
1485                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1486         return do_for_each_ref(get_main_ref_store(the_repository),
1487                                prefix, fn, 0, flag, cb_data);
1488 }
1489
1490 int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
1491                              each_ref_fn fn, void *cb_data,
1492                              unsigned int broken)
1493 {
1494         unsigned int flag = 0;
1495
1496         if (broken)
1497                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1498         return do_for_each_ref(refs, prefix, fn, 0, flag, cb_data);
1499 }
1500
1501 int for_each_replace_ref(struct repository *r, each_repo_ref_fn fn, void *cb_data)
1502 {
1503         return do_for_each_repo_ref(r, git_replace_ref_base, fn,
1504                                     strlen(git_replace_ref_base),
1505                                     DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1506 }
1507
1508 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1509 {
1510         struct strbuf buf = STRBUF_INIT;
1511         int ret;
1512         strbuf_addf(&buf, "%srefs/", get_git_namespace());
1513         ret = do_for_each_ref(get_main_ref_store(the_repository),
1514                               buf.buf, fn, 0, 0, cb_data);
1515         strbuf_release(&buf);
1516         return ret;
1517 }
1518
1519 int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1520 {
1521         return do_for_each_ref(refs, "", fn, 0,
1522                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1523 }
1524
1525 int for_each_rawref(each_ref_fn fn, void *cb_data)
1526 {
1527         return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
1528 }
1529
1530 static int refs_read_special_head(struct ref_store *ref_store,
1531                                   const char *refname, struct object_id *oid,
1532                                   struct strbuf *referent, unsigned int *type)
1533 {
1534         struct strbuf full_path = STRBUF_INIT;
1535         struct strbuf content = STRBUF_INIT;
1536         int result = -1;
1537         strbuf_addf(&full_path, "%s/%s", ref_store->gitdir, refname);
1538
1539         if (strbuf_read_file(&content, full_path.buf, 0) < 0)
1540                 goto done;
1541
1542         result = parse_loose_ref_contents(content.buf, oid, referent, type);
1543
1544 done:
1545         strbuf_release(&full_path);
1546         strbuf_release(&content);
1547         return result;
1548 }
1549
1550 int refs_read_raw_ref(struct ref_store *ref_store,
1551                       const char *refname, struct object_id *oid,
1552                       struct strbuf *referent, unsigned int *type)
1553 {
1554         if (!strcmp(refname, "FETCH_HEAD") || !strcmp(refname, "MERGE_HEAD")) {
1555                 return refs_read_special_head(ref_store, refname, oid, referent,
1556                                               type);
1557         }
1558
1559         return ref_store->be->read_raw_ref(ref_store, refname, oid, referent,
1560                                            type);
1561 }
1562
1563 /* This function needs to return a meaningful errno on failure */
1564 const char *refs_resolve_ref_unsafe(struct ref_store *refs,
1565                                     const char *refname,
1566                                     int resolve_flags,
1567                                     struct object_id *oid, int *flags)
1568 {
1569         static struct strbuf sb_refname = STRBUF_INIT;
1570         struct object_id unused_oid;
1571         int unused_flags;
1572         int symref_count;
1573
1574         if (!oid)
1575                 oid = &unused_oid;
1576         if (!flags)
1577                 flags = &unused_flags;
1578
1579         *flags = 0;
1580
1581         if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1582                 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1583                     !refname_is_safe(refname)) {
1584                         errno = EINVAL;
1585                         return NULL;
1586                 }
1587
1588                 /*
1589                  * dwim_ref() uses REF_ISBROKEN to distinguish between
1590                  * missing refs and refs that were present but invalid,
1591                  * to complain about the latter to stderr.
1592                  *
1593                  * We don't know whether the ref exists, so don't set
1594                  * REF_ISBROKEN yet.
1595                  */
1596                 *flags |= REF_BAD_NAME;
1597         }
1598
1599         for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
1600                 unsigned int read_flags = 0;
1601
1602                 if (refs_read_raw_ref(refs, refname,
1603                                       oid, &sb_refname, &read_flags)) {
1604                         *flags |= read_flags;
1605
1606                         /* In reading mode, refs must eventually resolve */
1607                         if (resolve_flags & RESOLVE_REF_READING)
1608                                 return NULL;
1609
1610                         /*
1611                          * Otherwise a missing ref is OK. But the files backend
1612                          * may show errors besides ENOENT if there are
1613                          * similarly-named refs.
1614                          */
1615                         if (errno != ENOENT &&
1616                             errno != EISDIR &&
1617                             errno != ENOTDIR)
1618                                 return NULL;
1619
1620                         oidclr(oid);
1621                         if (*flags & REF_BAD_NAME)
1622                                 *flags |= REF_ISBROKEN;
1623                         return refname;
1624                 }
1625
1626                 *flags |= read_flags;
1627
1628                 if (!(read_flags & REF_ISSYMREF)) {
1629                         if (*flags & REF_BAD_NAME) {
1630                                 oidclr(oid);
1631                                 *flags |= REF_ISBROKEN;
1632                         }
1633                         return refname;
1634                 }
1635
1636                 refname = sb_refname.buf;
1637                 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1638                         oidclr(oid);
1639                         return refname;
1640                 }
1641                 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1642                         if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1643                             !refname_is_safe(refname)) {
1644                                 errno = EINVAL;
1645                                 return NULL;
1646                         }
1647
1648                         *flags |= REF_ISBROKEN | REF_BAD_NAME;
1649                 }
1650         }
1651
1652         errno = ELOOP;
1653         return NULL;
1654 }
1655
1656 /* backend functions */
1657 int refs_init_db(struct strbuf *err)
1658 {
1659         struct ref_store *refs = get_main_ref_store(the_repository);
1660
1661         return refs->be->init_db(refs, err);
1662 }
1663
1664 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1665                                struct object_id *oid, int *flags)
1666 {
1667         return refs_resolve_ref_unsafe(get_main_ref_store(the_repository), refname,
1668                                        resolve_flags, oid, flags);
1669 }
1670
1671 int resolve_gitlink_ref(const char *submodule, const char *refname,
1672                         struct object_id *oid)
1673 {
1674         struct ref_store *refs;
1675         int flags;
1676
1677         refs = get_submodule_ref_store(submodule);
1678
1679         if (!refs)
1680                 return -1;
1681
1682         if (!refs_resolve_ref_unsafe(refs, refname, 0, oid, &flags) ||
1683             is_null_oid(oid))
1684                 return -1;
1685         return 0;
1686 }
1687
1688 struct ref_store_hash_entry
1689 {
1690         struct hashmap_entry ent;
1691
1692         struct ref_store *refs;
1693
1694         /* NUL-terminated identifier of the ref store: */
1695         char name[FLEX_ARRAY];
1696 };
1697
1698 static int ref_store_hash_cmp(const void *unused_cmp_data,
1699                               const struct hashmap_entry *eptr,
1700                               const struct hashmap_entry *entry_or_key,
1701                               const void *keydata)
1702 {
1703         const struct ref_store_hash_entry *e1, *e2;
1704         const char *name;
1705
1706         e1 = container_of(eptr, const struct ref_store_hash_entry, ent);
1707         e2 = container_of(entry_or_key, const struct ref_store_hash_entry, ent);
1708         name = keydata ? keydata : e2->name;
1709
1710         return strcmp(e1->name, name);
1711 }
1712
1713 static struct ref_store_hash_entry *alloc_ref_store_hash_entry(
1714                 const char *name, struct ref_store *refs)
1715 {
1716         struct ref_store_hash_entry *entry;
1717
1718         FLEX_ALLOC_STR(entry, name, name);
1719         hashmap_entry_init(&entry->ent, strhash(name));
1720         entry->refs = refs;
1721         return entry;
1722 }
1723
1724 /* A hashmap of ref_stores, stored by submodule name: */
1725 static struct hashmap submodule_ref_stores;
1726
1727 /* A hashmap of ref_stores, stored by worktree id: */
1728 static struct hashmap worktree_ref_stores;
1729
1730 /*
1731  * Look up a ref store by name. If that ref_store hasn't been
1732  * registered yet, return NULL.
1733  */
1734 static struct ref_store *lookup_ref_store_map(struct hashmap *map,
1735                                               const char *name)
1736 {
1737         struct ref_store_hash_entry *entry;
1738         unsigned int hash;
1739
1740         if (!map->tablesize)
1741                 /* It's initialized on demand in register_ref_store(). */
1742                 return NULL;
1743
1744         hash = strhash(name);
1745         entry = hashmap_get_entry_from_hash(map, hash, name,
1746                                         struct ref_store_hash_entry, ent);
1747         return entry ? entry->refs : NULL;
1748 }
1749
1750 /*
1751  * Create, record, and return a ref_store instance for the specified
1752  * gitdir.
1753  */
1754 static struct ref_store *ref_store_init(const char *gitdir,
1755                                         unsigned int flags)
1756 {
1757         const char *be_name = "files";
1758         struct ref_storage_be *be = find_ref_storage_backend(be_name);
1759         struct ref_store *refs;
1760
1761         if (!be)
1762                 BUG("reference backend %s is unknown", be_name);
1763
1764         refs = be->init(gitdir, flags);
1765         return refs;
1766 }
1767
1768 struct ref_store *get_main_ref_store(struct repository *r)
1769 {
1770         if (r->refs_private)
1771                 return r->refs_private;
1772
1773         if (!r->gitdir)
1774                 BUG("attempting to get main_ref_store outside of repository");
1775
1776         r->refs_private = ref_store_init(r->gitdir, REF_STORE_ALL_CAPS);
1777         r->refs_private = maybe_debug_wrap_ref_store(r->gitdir, r->refs_private);
1778         return r->refs_private;
1779 }
1780
1781 /*
1782  * Associate a ref store with a name. It is a fatal error to call this
1783  * function twice for the same name.
1784  */
1785 static void register_ref_store_map(struct hashmap *map,
1786                                    const char *type,
1787                                    struct ref_store *refs,
1788                                    const char *name)
1789 {
1790         struct ref_store_hash_entry *entry;
1791
1792         if (!map->tablesize)
1793                 hashmap_init(map, ref_store_hash_cmp, NULL, 0);
1794
1795         entry = alloc_ref_store_hash_entry(name, refs);
1796         if (hashmap_put(map, &entry->ent))
1797                 BUG("%s ref_store '%s' initialized twice", type, name);
1798 }
1799
1800 struct ref_store *get_submodule_ref_store(const char *submodule)
1801 {
1802         struct strbuf submodule_sb = STRBUF_INIT;
1803         struct ref_store *refs;
1804         char *to_free = NULL;
1805         size_t len;
1806
1807         if (!submodule)
1808                 return NULL;
1809
1810         len = strlen(submodule);
1811         while (len && is_dir_sep(submodule[len - 1]))
1812                 len--;
1813         if (!len)
1814                 return NULL;
1815
1816         if (submodule[len])
1817                 /* We need to strip off one or more trailing slashes */
1818                 submodule = to_free = xmemdupz(submodule, len);
1819
1820         refs = lookup_ref_store_map(&submodule_ref_stores, submodule);
1821         if (refs)
1822                 goto done;
1823
1824         strbuf_addstr(&submodule_sb, submodule);
1825         if (!is_nonbare_repository_dir(&submodule_sb))
1826                 goto done;
1827
1828         if (submodule_to_gitdir(&submodule_sb, submodule))
1829                 goto done;
1830
1831         /* assume that add_submodule_odb() has been called */
1832         refs = ref_store_init(submodule_sb.buf,
1833                               REF_STORE_READ | REF_STORE_ODB);
1834         register_ref_store_map(&submodule_ref_stores, "submodule",
1835                                refs, submodule);
1836
1837 done:
1838         strbuf_release(&submodule_sb);
1839         free(to_free);
1840
1841         return refs;
1842 }
1843
1844 struct ref_store *get_worktree_ref_store(const struct worktree *wt)
1845 {
1846         struct ref_store *refs;
1847         const char *id;
1848
1849         if (wt->is_current)
1850                 return get_main_ref_store(the_repository);
1851
1852         id = wt->id ? wt->id : "/";
1853         refs = lookup_ref_store_map(&worktree_ref_stores, id);
1854         if (refs)
1855                 return refs;
1856
1857         if (wt->id)
1858                 refs = ref_store_init(git_common_path("worktrees/%s", wt->id),
1859                                       REF_STORE_ALL_CAPS);
1860         else
1861                 refs = ref_store_init(get_git_common_dir(),
1862                                       REF_STORE_ALL_CAPS);
1863
1864         if (refs)
1865                 register_ref_store_map(&worktree_ref_stores, "worktree",
1866                                        refs, id);
1867         return refs;
1868 }
1869
1870 void base_ref_store_init(struct ref_store *refs,
1871                          const struct ref_storage_be *be)
1872 {
1873         refs->be = be;
1874 }
1875
1876 /* backend functions */
1877 int refs_pack_refs(struct ref_store *refs, unsigned int flags)
1878 {
1879         return refs->be->pack_refs(refs, flags);
1880 }
1881
1882 int refs_peel_ref(struct ref_store *refs, const char *refname,
1883                   struct object_id *oid)
1884 {
1885         int flag;
1886         struct object_id base;
1887
1888         if (current_ref_iter && current_ref_iter->refname == refname) {
1889                 struct object_id peeled;
1890
1891                 if (ref_iterator_peel(current_ref_iter, &peeled))
1892                         return -1;
1893                 oidcpy(oid, &peeled);
1894                 return 0;
1895         }
1896
1897         if (refs_read_ref_full(refs, refname,
1898                                RESOLVE_REF_READING, &base, &flag))
1899                 return -1;
1900
1901         return peel_object(&base, oid);
1902 }
1903
1904 int peel_ref(const char *refname, struct object_id *oid)
1905 {
1906         return refs_peel_ref(get_main_ref_store(the_repository), refname, oid);
1907 }
1908
1909 int refs_create_symref(struct ref_store *refs,
1910                        const char *ref_target,
1911                        const char *refs_heads_master,
1912                        const char *logmsg)
1913 {
1914         char *msg;
1915         int retval;
1916
1917         msg = normalize_reflog_message(logmsg);
1918         retval = refs->be->create_symref(refs, ref_target, refs_heads_master,
1919                                          msg);
1920         free(msg);
1921         return retval;
1922 }
1923
1924 int create_symref(const char *ref_target, const char *refs_heads_master,
1925                   const char *logmsg)
1926 {
1927         return refs_create_symref(get_main_ref_store(the_repository), ref_target,
1928                                   refs_heads_master, logmsg);
1929 }
1930
1931 int ref_update_reject_duplicates(struct string_list *refnames,
1932                                  struct strbuf *err)
1933 {
1934         size_t i, n = refnames->nr;
1935
1936         assert(err);
1937
1938         for (i = 1; i < n; i++) {
1939                 int cmp = strcmp(refnames->items[i - 1].string,
1940                                  refnames->items[i].string);
1941
1942                 if (!cmp) {
1943                         strbuf_addf(err,
1944                                     _("multiple updates for ref '%s' not allowed"),
1945                                     refnames->items[i].string);
1946                         return 1;
1947                 } else if (cmp > 0) {
1948                         BUG("ref_update_reject_duplicates() received unsorted list");
1949                 }
1950         }
1951         return 0;
1952 }
1953
1954 static int run_transaction_hook(struct ref_transaction *transaction,
1955                                 const char *state)
1956 {
1957         struct child_process proc = CHILD_PROCESS_INIT;
1958         struct strbuf buf = STRBUF_INIT;
1959         const char *hook;
1960         int ret = 0, i;
1961
1962         hook = find_hook("reference-transaction");
1963         if (!hook)
1964                 return ret;
1965
1966         strvec_pushl(&proc.args, hook, state, NULL);
1967         proc.in = -1;
1968         proc.stdout_to_stderr = 1;
1969         proc.trace2_hook_name = "reference-transaction";
1970
1971         ret = start_command(&proc);
1972         if (ret)
1973                 return ret;
1974
1975         sigchain_push(SIGPIPE, SIG_IGN);
1976
1977         for (i = 0; i < transaction->nr; i++) {
1978                 struct ref_update *update = transaction->updates[i];
1979
1980                 strbuf_reset(&buf);
1981                 strbuf_addf(&buf, "%s %s %s\n",
1982                             oid_to_hex(&update->old_oid),
1983                             oid_to_hex(&update->new_oid),
1984                             update->refname);
1985
1986                 if (write_in_full(proc.in, buf.buf, buf.len) < 0) {
1987                         if (errno != EPIPE)
1988                                 ret = -1;
1989                         break;
1990                 }
1991         }
1992
1993         close(proc.in);
1994         sigchain_pop(SIGPIPE);
1995         strbuf_release(&buf);
1996
1997         ret |= finish_command(&proc);
1998         return ret;
1999 }
2000
2001 int ref_transaction_prepare(struct ref_transaction *transaction,
2002                             struct strbuf *err)
2003 {
2004         struct ref_store *refs = transaction->ref_store;
2005         int ret;
2006
2007         switch (transaction->state) {
2008         case REF_TRANSACTION_OPEN:
2009                 /* Good. */
2010                 break;
2011         case REF_TRANSACTION_PREPARED:
2012                 BUG("prepare called twice on reference transaction");
2013                 break;
2014         case REF_TRANSACTION_CLOSED:
2015                 BUG("prepare called on a closed reference transaction");
2016                 break;
2017         default:
2018                 BUG("unexpected reference transaction state");
2019                 break;
2020         }
2021
2022         if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
2023                 strbuf_addstr(err,
2024                               _("ref updates forbidden inside quarantine environment"));
2025                 return -1;
2026         }
2027
2028         ret = refs->be->transaction_prepare(refs, transaction, err);
2029         if (ret)
2030                 return ret;
2031
2032         ret = run_transaction_hook(transaction, "prepared");
2033         if (ret) {
2034                 ref_transaction_abort(transaction, err);
2035                 die(_("ref updates aborted by hook"));
2036         }
2037
2038         return 0;
2039 }
2040
2041 int ref_transaction_abort(struct ref_transaction *transaction,
2042                           struct strbuf *err)
2043 {
2044         struct ref_store *refs = transaction->ref_store;
2045         int ret = 0;
2046
2047         switch (transaction->state) {
2048         case REF_TRANSACTION_OPEN:
2049                 /* No need to abort explicitly. */
2050                 break;
2051         case REF_TRANSACTION_PREPARED:
2052                 ret = refs->be->transaction_abort(refs, transaction, err);
2053                 break;
2054         case REF_TRANSACTION_CLOSED:
2055                 BUG("abort called on a closed reference transaction");
2056                 break;
2057         default:
2058                 BUG("unexpected reference transaction state");
2059                 break;
2060         }
2061
2062         run_transaction_hook(transaction, "aborted");
2063
2064         ref_transaction_free(transaction);
2065         return ret;
2066 }
2067
2068 int ref_transaction_commit(struct ref_transaction *transaction,
2069                            struct strbuf *err)
2070 {
2071         struct ref_store *refs = transaction->ref_store;
2072         int ret;
2073
2074         switch (transaction->state) {
2075         case REF_TRANSACTION_OPEN:
2076                 /* Need to prepare first. */
2077                 ret = ref_transaction_prepare(transaction, err);
2078                 if (ret)
2079                         return ret;
2080                 break;
2081         case REF_TRANSACTION_PREPARED:
2082                 /* Fall through to finish. */
2083                 break;
2084         case REF_TRANSACTION_CLOSED:
2085                 BUG("commit called on a closed reference transaction");
2086                 break;
2087         default:
2088                 BUG("unexpected reference transaction state");
2089                 break;
2090         }
2091
2092         ret = refs->be->transaction_finish(refs, transaction, err);
2093         if (!ret)
2094                 run_transaction_hook(transaction, "committed");
2095         return ret;
2096 }
2097
2098 int refs_verify_refname_available(struct ref_store *refs,
2099                                   const char *refname,
2100                                   const struct string_list *extras,
2101                                   const struct string_list *skip,
2102                                   struct strbuf *err)
2103 {
2104         const char *slash;
2105         const char *extra_refname;
2106         struct strbuf dirname = STRBUF_INIT;
2107         struct strbuf referent = STRBUF_INIT;
2108         struct object_id oid;
2109         unsigned int type;
2110         struct ref_iterator *iter;
2111         int ok;
2112         int ret = -1;
2113
2114         /*
2115          * For the sake of comments in this function, suppose that
2116          * refname is "refs/foo/bar".
2117          */
2118
2119         assert(err);
2120
2121         strbuf_grow(&dirname, strlen(refname) + 1);
2122         for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
2123                 /* Expand dirname to the new prefix, not including the trailing slash: */
2124                 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
2125
2126                 /*
2127                  * We are still at a leading dir of the refname (e.g.,
2128                  * "refs/foo"; if there is a reference with that name,
2129                  * it is a conflict, *unless* it is in skip.
2130                  */
2131                 if (skip && string_list_has_string(skip, dirname.buf))
2132                         continue;
2133
2134                 if (!refs_read_raw_ref(refs, dirname.buf, &oid, &referent, &type)) {
2135                         strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
2136                                     dirname.buf, refname);
2137                         goto cleanup;
2138                 }
2139
2140                 if (extras && string_list_has_string(extras, dirname.buf)) {
2141                         strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
2142                                     refname, dirname.buf);
2143                         goto cleanup;
2144                 }
2145         }
2146
2147         /*
2148          * We are at the leaf of our refname (e.g., "refs/foo/bar").
2149          * There is no point in searching for a reference with that
2150          * name, because a refname isn't considered to conflict with
2151          * itself. But we still need to check for references whose
2152          * names are in the "refs/foo/bar/" namespace, because they
2153          * *do* conflict.
2154          */
2155         strbuf_addstr(&dirname, refname + dirname.len);
2156         strbuf_addch(&dirname, '/');
2157
2158         iter = refs_ref_iterator_begin(refs, dirname.buf, 0,
2159                                        DO_FOR_EACH_INCLUDE_BROKEN);
2160         while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
2161                 if (skip &&
2162                     string_list_has_string(skip, iter->refname))
2163                         continue;
2164
2165                 strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
2166                             iter->refname, refname);
2167                 ref_iterator_abort(iter);
2168                 goto cleanup;
2169         }
2170
2171         if (ok != ITER_DONE)
2172                 BUG("error while iterating over references");
2173
2174         extra_refname = find_descendant_ref(dirname.buf, extras, skip);
2175         if (extra_refname)
2176                 strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
2177                             refname, extra_refname);
2178         else
2179                 ret = 0;
2180
2181 cleanup:
2182         strbuf_release(&referent);
2183         strbuf_release(&dirname);
2184         return ret;
2185 }
2186
2187 int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2188 {
2189         struct ref_iterator *iter;
2190         struct do_for_each_ref_help hp = { fn, cb_data };
2191
2192         iter = refs->be->reflog_iterator_begin(refs);
2193
2194         return do_for_each_repo_ref_iterator(the_repository, iter,
2195                                              do_for_each_ref_helper, &hp);
2196 }
2197
2198 int for_each_reflog(each_ref_fn fn, void *cb_data)
2199 {
2200         return refs_for_each_reflog(get_main_ref_store(the_repository), fn, cb_data);
2201 }
2202
2203 int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
2204                                      const char *refname,
2205                                      each_reflog_ent_fn fn,
2206                                      void *cb_data)
2207 {
2208         return refs->be->for_each_reflog_ent_reverse(refs, refname,
2209                                                      fn, cb_data);
2210 }
2211
2212 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
2213                                 void *cb_data)
2214 {
2215         return refs_for_each_reflog_ent_reverse(get_main_ref_store(the_repository),
2216                                                 refname, fn, cb_data);
2217 }
2218
2219 int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
2220                              each_reflog_ent_fn fn, void *cb_data)
2221 {
2222         return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
2223 }
2224
2225 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
2226                         void *cb_data)
2227 {
2228         return refs_for_each_reflog_ent(get_main_ref_store(the_repository), refname,
2229                                         fn, cb_data);
2230 }
2231
2232 int refs_reflog_exists(struct ref_store *refs, const char *refname)
2233 {
2234         return refs->be->reflog_exists(refs, refname);
2235 }
2236
2237 int reflog_exists(const char *refname)
2238 {
2239         return refs_reflog_exists(get_main_ref_store(the_repository), refname);
2240 }
2241
2242 int refs_create_reflog(struct ref_store *refs, const char *refname,
2243                        int force_create, struct strbuf *err)
2244 {
2245         return refs->be->create_reflog(refs, refname, force_create, err);
2246 }
2247
2248 int safe_create_reflog(const char *refname, int force_create,
2249                        struct strbuf *err)
2250 {
2251         return refs_create_reflog(get_main_ref_store(the_repository), refname,
2252                                   force_create, err);
2253 }
2254
2255 int refs_delete_reflog(struct ref_store *refs, const char *refname)
2256 {
2257         return refs->be->delete_reflog(refs, refname);
2258 }
2259
2260 int delete_reflog(const char *refname)
2261 {
2262         return refs_delete_reflog(get_main_ref_store(the_repository), refname);
2263 }
2264
2265 int refs_reflog_expire(struct ref_store *refs,
2266                        const char *refname, const struct object_id *oid,
2267                        unsigned int flags,
2268                        reflog_expiry_prepare_fn prepare_fn,
2269                        reflog_expiry_should_prune_fn should_prune_fn,
2270                        reflog_expiry_cleanup_fn cleanup_fn,
2271                        void *policy_cb_data)
2272 {
2273         return refs->be->reflog_expire(refs, refname, oid, flags,
2274                                        prepare_fn, should_prune_fn,
2275                                        cleanup_fn, policy_cb_data);
2276 }
2277
2278 int reflog_expire(const char *refname, const struct object_id *oid,
2279                   unsigned int flags,
2280                   reflog_expiry_prepare_fn prepare_fn,
2281                   reflog_expiry_should_prune_fn should_prune_fn,
2282                   reflog_expiry_cleanup_fn cleanup_fn,
2283                   void *policy_cb_data)
2284 {
2285         return refs_reflog_expire(get_main_ref_store(the_repository),
2286                                   refname, oid, flags,
2287                                   prepare_fn, should_prune_fn,
2288                                   cleanup_fn, policy_cb_data);
2289 }
2290
2291 int initial_ref_transaction_commit(struct ref_transaction *transaction,
2292                                    struct strbuf *err)
2293 {
2294         struct ref_store *refs = transaction->ref_store;
2295
2296         return refs->be->initial_transaction_commit(refs, transaction, err);
2297 }
2298
2299 int refs_delete_refs(struct ref_store *refs, const char *logmsg,
2300                      struct string_list *refnames, unsigned int flags)
2301 {
2302         char *msg;
2303         int retval;
2304
2305         msg = normalize_reflog_message(logmsg);
2306         retval = refs->be->delete_refs(refs, msg, refnames, flags);
2307         free(msg);
2308         return retval;
2309 }
2310
2311 int delete_refs(const char *msg, struct string_list *refnames,
2312                 unsigned int flags)
2313 {
2314         return refs_delete_refs(get_main_ref_store(the_repository), msg, refnames, flags);
2315 }
2316
2317 int refs_rename_ref(struct ref_store *refs, const char *oldref,
2318                     const char *newref, const char *logmsg)
2319 {
2320         char *msg;
2321         int retval;
2322
2323         msg = normalize_reflog_message(logmsg);
2324         retval = refs->be->rename_ref(refs, oldref, newref, msg);
2325         free(msg);
2326         return retval;
2327 }
2328
2329 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
2330 {
2331         return refs_rename_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
2332 }
2333
2334 int refs_copy_existing_ref(struct ref_store *refs, const char *oldref,
2335                     const char *newref, const char *logmsg)
2336 {
2337         char *msg;
2338         int retval;
2339
2340         msg = normalize_reflog_message(logmsg);
2341         retval = refs->be->copy_ref(refs, oldref, newref, msg);
2342         free(msg);
2343         return retval;
2344 }
2345
2346 int copy_existing_ref(const char *oldref, const char *newref, const char *logmsg)
2347 {
2348         return refs_copy_existing_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
2349 }