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 "hashmap.h"
   7 #include "lockfile.h"
   8 #include "iterator.h"
   9 #include "refs.h"
  10 #include "refs/refs-internal.h"
  11 #include "object.h"
  12 #include "tag.h"
  13 #include "submodule.h"
  14 #include "worktree.h"
  15
  16 /*
  17  * List of all available backends
  18  */
  19 static struct ref_storage_be *refs_backends = &refs_be_files;
  20
  21 static struct ref_storage_be *find_ref_storage_backend(const char *name)
  22 {
  23         struct ref_storage_be *be;
  24         for (be = refs_backends; be; be = be->next)
  25                 if (!strcmp(be->name, name))
  26                         return be;
  27         return NULL;
  28 }
  29
  30 int ref_storage_backend_exists(const char *name)
  31 {
  32         return find_ref_storage_backend(name) != NULL;
  33 }
  34
  35 /*
  36  * How to handle various characters in refnames:
  37  * 0: An acceptable character for refs
  38  * 1: End-of-component
  39  * 2: ., look for a preceding . to reject .. in refs
  40  * 3: {, look for a preceding @ to reject @{ in refs
  41  * 4: A bad character: ASCII control characters, and
  42  *    ":", "?", "[", "\", "^", "~", SP, or TAB
  43  * 5: *, reject unless REFNAME_REFSPEC_PATTERN is set
  44  */
  45 static unsigned char refname_disposition[256] = {
  46         1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
  47         4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
  48         4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 1,
  49         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
  50         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  51         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
  52         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  53         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
  54 };
  55
  56 /*
  57  * Try to read one refname component from the front of refname.
  58  * Return the length of the component found, or -1 if the component is
  59  * not legal.  It is legal if it is something reasonable to have under
  60  * ".git/refs/"; We do not like it if:
  61  *
  62  * - any path component of it begins with ".", or
  63  * - it has double dots "..", or
  64  * - it has ASCII control characters, or
  65  * - it has ":", "?", "[", "\", "^", "~", SP, or TAB anywhere, or
  66  * - it has "*" anywhere unless REFNAME_REFSPEC_PATTERN is set, or
  67  * - it ends with a "/", or
  68  * - it ends with ".lock", or
  69  * - it contains a "@{" portion
  70  */
  71 static int check_refname_component(const char *refname, int *flags)
  72 {
  73         const char *cp;
  74         char last = '\0';
  75
  76         for (cp = refname; ; cp++) {
  77                 int ch = *cp & 255;
  78                 unsigned char disp = refname_disposition[ch];
  79                 switch (disp) {
  80                 case 1:
  81                         goto out;
  82                 case 2:
  83                         if (last == '.')
  84                                 return -1; /* Refname contains "..". */
  85                         break;
  86                 case 3:
  87                         if (last == '@')
  88                                 return -1; /* Refname contains "@{". */
  89                         break;
  90                 case 4:
  91                         return -1;
  92                 case 5:
  93                         if (!(*flags & REFNAME_REFSPEC_PATTERN))
  94                                 return -1; /* refspec can't be a pattern */
  95
  96                         /*
  97                          * Unset the pattern flag so that we only accept
  98                          * a single asterisk for one side of refspec.
  99                          */
 100                         *flags &= ~ REFNAME_REFSPEC_PATTERN;
 101                         break;
 102                 }
 103                 last = ch;
 104         }
 105 out:
 106         if (cp == refname)
 107                 return 0; /* Component has zero length. */
 108         if (refname[0] == '.')
 109                 return -1; /* Component starts with '.'. */
 110         if (cp - refname >= LOCK_SUFFIX_LEN &&
 111             !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
 112                 return -1; /* Refname ends with ".lock". */
 113         return cp - refname;
 114 }
 115
 116 int check_refname_format(const char *refname, int flags)
 117 {
 118         int component_len, component_count = 0;
 119
 120         if (!strcmp(refname, "@"))
 121                 /* Refname is a single character '@'. */
 122                 return -1;
 123
 124         while (1) {
 125                 /* We are at the start of a path component. */
 126                 component_len = check_refname_component(refname, &flags);
 127                 if (component_len <= 0)
 128                         return -1;
 129
 130                 component_count++;
 131                 if (refname[component_len] == '\0')
 132                         break;
 133                 /* Skip to next component. */
 134                 refname += component_len + 1;
 135         }
 136
 137         if (refname[component_len - 1] == '.')
 138                 return -1; /* Refname ends with '.'. */
 139         if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
 140                 return -1; /* Refname has only one component. */
 141         return 0;
 142 }
 143
 144 int refname_is_safe(const char *refname)
 145 {
 146         const char *rest;
 147
 148         if (skip_prefix(refname, "refs/", &rest)) {
 149                 char *buf;
 150                 int result;
 151                 size_t restlen = strlen(rest);
 152
 153                 /* rest must not be empty, or start or end with "/" */
 154                 if (!restlen || *rest == '/' || rest[restlen - 1] == '/')
 155                         return 0;
 156
 157                 /*
 158                  * Does the refname try to escape refs/?
 159                  * For example: refs/foo/../bar is safe but refs/foo/../../bar
 160                  * is not.
 161                  */
 162                 buf = xmallocz(restlen);
 163                 result = !normalize_path_copy(buf, rest) && !strcmp(buf, rest);
 164                 free(buf);
 165                 return result;
 166         }
 167
 168         do {
 169                 if (!isupper(*refname) && *refname != '_')
 170                         return 0;
 171                 refname++;
 172         } while (*refname);
 173         return 1;
 174 }
 175
 176 char *refs_resolve_refdup(struct ref_store *refs,
 177                           const char *refname, int resolve_flags,
 178                           unsigned char *sha1, int *flags)
 179 {
 180         const char *result;
 181
 182         result = refs_resolve_ref_unsafe(refs, refname, resolve_flags,
 183                                          sha1, flags);
 184         return xstrdup_or_null(result);
 185 }
 186
 187 char *resolve_refdup(const char *refname, int resolve_flags,
 188                      unsigned char *sha1, int *flags)
 189 {
 190         return refs_resolve_refdup(get_main_ref_store(),
 191                                    refname, resolve_flags,
 192                                    sha1, flags);
 193 }
 194
 195 /* The argument to filter_refs */
 196 struct ref_filter {
 197         const char *pattern;
 198         each_ref_fn *fn;
 199         void *cb_data;
 200 };
 201
 202 int refs_read_ref_full(struct ref_store *refs, const char *refname,
 203                        int resolve_flags, unsigned char *sha1, int *flags)
 204 {
 205         if (refs_resolve_ref_unsafe(refs, refname, resolve_flags, sha1, flags))
 206                 return 0;
 207         return -1;
 208 }
 209
 210 int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
 211 {
 212         return refs_read_ref_full(get_main_ref_store(), refname,
 213                                   resolve_flags, sha1, flags);
 214 }
 215
 216 int read_ref(const char *refname, unsigned char *sha1)
 217 {
 218         return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
 219 }
 220
 221 int ref_exists(const char *refname)
 222 {
 223         unsigned char sha1[20];
 224         return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
 225 }
 226
 227 static int filter_refs(const char *refname, const struct object_id *oid,
 228                            int flags, void *data)
 229 {
 230         struct ref_filter *filter = (struct ref_filter *)data;
 231
 232         if (wildmatch(filter->pattern, refname, 0, NULL))
 233                 return 0;
 234         return filter->fn(refname, oid, flags, filter->cb_data);
 235 }
 236
 237 enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
 238 {
 239         struct object *o = lookup_unknown_object(name);
 240
 241         if (o->type == OBJ_NONE) {
 242                 int type = sha1_object_info(name, NULL);
 243                 if (type < 0 || !object_as_type(o, type, 0))
 244                         return PEEL_INVALID;
 245         }
 246
 247         if (o->type != OBJ_TAG)
 248                 return PEEL_NON_TAG;
 249
 250         o = deref_tag_noverify(o);
 251         if (!o)
 252                 return PEEL_INVALID;
 253
 254         hashcpy(sha1, o->oid.hash);
 255         return PEEL_PEELED;
 256 }
 257
 258 struct warn_if_dangling_data {
 259         FILE *fp;
 260         const char *refname;
 261         const struct string_list *refnames;
 262         const char *msg_fmt;
 263 };
 264
 265 static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
 266                                    int flags, void *cb_data)
 267 {
 268         struct warn_if_dangling_data *d = cb_data;
 269         const char *resolves_to;
 270         struct object_id junk;
 271
 272         if (!(flags & REF_ISSYMREF))
 273                 return 0;
 274
 275         resolves_to = resolve_ref_unsafe(refname, 0, junk.hash, NULL);
 276         if (!resolves_to
 277             || (d->refname
 278                 ? strcmp(resolves_to, d->refname)
 279                 : !string_list_has_string(d->refnames, resolves_to))) {
 280                 return 0;
 281         }
 282
 283         fprintf(d->fp, d->msg_fmt, refname);
 284         fputc('\n', d->fp);
 285         return 0;
 286 }
 287
 288 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 289 {
 290         struct warn_if_dangling_data data;
 291
 292         data.fp = fp;
 293         data.refname = refname;
 294         data.refnames = NULL;
 295         data.msg_fmt = msg_fmt;
 296         for_each_rawref(warn_if_dangling_symref, &data);
 297 }
 298
 299 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
 300 {
 301         struct warn_if_dangling_data data;
 302
 303         data.fp = fp;
 304         data.refname = NULL;
 305         data.refnames = refnames;
 306         data.msg_fmt = msg_fmt;
 307         for_each_rawref(warn_if_dangling_symref, &data);
 308 }
 309
 310 int refs_for_each_tag_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 311 {
 312         return refs_for_each_ref_in(refs, "refs/tags/", fn, cb_data);
 313 }
 314
 315 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 316 {
 317         return refs_for_each_tag_ref(get_main_ref_store(), fn, cb_data);
 318 }
 319
 320 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 321 {
 322         return refs_for_each_tag_ref(get_submodule_ref_store(submodule),
 323                                      fn, cb_data);
 324 }
 325
 326 int refs_for_each_branch_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 327 {
 328         return refs_for_each_ref_in(refs, "refs/heads/", fn, cb_data);
 329 }
 330
 331 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 332 {
 333         return refs_for_each_branch_ref(get_main_ref_store(), fn, cb_data);
 334 }
 335
 336 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 337 {
 338         return refs_for_each_branch_ref(get_submodule_ref_store(submodule),
 339                                         fn, cb_data);
 340 }
 341
 342 int refs_for_each_remote_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 343 {
 344         return refs_for_each_ref_in(refs, "refs/remotes/", fn, cb_data);
 345 }
 346
 347 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 348 {
 349         return refs_for_each_remote_ref(get_main_ref_store(), fn, cb_data);
 350 }
 351
 352 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 353 {
 354         return refs_for_each_remote_ref(get_submodule_ref_store(submodule),
 355                                         fn, cb_data);
 356 }
 357
 358 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
 359 {
 360         struct strbuf buf = STRBUF_INIT;
 361         int ret = 0;
 362         struct object_id oid;
 363         int flag;
 364
 365         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
 366         if (!read_ref_full(buf.buf, RESOLVE_REF_READING, oid.hash, &flag))
 367                 ret = fn(buf.buf, &oid, flag, cb_data);
 368         strbuf_release(&buf);
 369
 370         return ret;
 371 }
 372
 373 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 374         const char *prefix, void *cb_data)
 375 {
 376         struct strbuf real_pattern = STRBUF_INIT;
 377         struct ref_filter filter;
 378         int ret;
 379
 380         if (!prefix && !starts_with(pattern, "refs/"))
 381                 strbuf_addstr(&real_pattern, "refs/");
 382         else if (prefix)
 383                 strbuf_addstr(&real_pattern, prefix);
 384         strbuf_addstr(&real_pattern, pattern);
 385
 386         if (!has_glob_specials(pattern)) {
 387                 /* Append implied '/' '*' if not present. */
 388                 strbuf_complete(&real_pattern, '/');
 389                 /* No need to check for '*', there is none. */
 390                 strbuf_addch(&real_pattern, '*');
 391         }
 392
 393         filter.pattern = real_pattern.buf;
 394         filter.fn = fn;
 395         filter.cb_data = cb_data;
 396         ret = for_each_ref(filter_refs, &filter);
 397
 398         strbuf_release(&real_pattern);
 399         return ret;
 400 }
 401
 402 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
 403 {
 404         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
 405 }
 406
 407 const char *prettify_refname(const char *name)
 408 {
 409         if (skip_prefix(name, "refs/heads/", &name) ||
 410             skip_prefix(name, "refs/tags/", &name) ||
 411             skip_prefix(name, "refs/remotes/", &name))
 412                 ; /* nothing */
 413         return name;
 414 }
 415
 416 static const char *ref_rev_parse_rules[] = {
 417         "%.*s",
 418         "refs/%.*s",
 419         "refs/tags/%.*s",
 420         "refs/heads/%.*s",
 421         "refs/remotes/%.*s",
 422         "refs/remotes/%.*s/HEAD",
 423         NULL
 424 };
 425
 426 int refname_match(const char *abbrev_name, const char *full_name)
 427 {
 428         const char **p;
 429         const int abbrev_name_len = strlen(abbrev_name);
 430
 431         for (p = ref_rev_parse_rules; *p; p++) {
 432                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 433                         return 1;
 434                 }
 435         }
 436
 437         return 0;
 438 }
 439
 440 /*
 441  * *string and *len will only be substituted, and *string returned (for
 442  * later free()ing) if the string passed in is a magic short-hand form
 443  * to name a branch.
 444  */
 445 static char *substitute_branch_name(const char **string, int *len)
 446 {
 447         struct strbuf buf = STRBUF_INIT;
 448         int ret = interpret_branch_name(*string, *len, &buf, 0);
 449
 450         if (ret == *len) {
 451                 size_t size;
 452                 *string = strbuf_detach(&buf, &size);
 453                 *len = size;
 454                 return (char *)*string;
 455         }
 456
 457         return NULL;
 458 }
 459
 460 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 461 {
 462         char *last_branch = substitute_branch_name(&str, &len);
 463         int   refs_found  = expand_ref(str, len, sha1, ref);
 464         free(last_branch);
 465         return refs_found;
 466 }
 467
 468 int expand_ref(const char *str, int len, unsigned char *sha1, char **ref)
 469 {
 470         const char **p, *r;
 471         int refs_found = 0;
 472         struct strbuf fullref = STRBUF_INIT;
 473
 474         *ref = NULL;
 475         for (p = ref_rev_parse_rules; *p; p++) {
 476                 unsigned char sha1_from_ref[20];
 477                 unsigned char *this_result;
 478                 int flag;
 479
 480                 this_result = refs_found ? sha1_from_ref : sha1;
 481                 strbuf_reset(&fullref);
 482                 strbuf_addf(&fullref, *p, len, str);
 483                 r = resolve_ref_unsafe(fullref.buf, RESOLVE_REF_READING,
 484                                        this_result, &flag);
 485                 if (r) {
 486                         if (!refs_found++)
 487                                 *ref = xstrdup(r);
 488                         if (!warn_ambiguous_refs)
 489                                 break;
 490                 } else if ((flag & REF_ISSYMREF) && strcmp(fullref.buf, "HEAD")) {
 491                         warning("ignoring dangling symref %s.", fullref.buf);
 492                 } else if ((flag & REF_ISBROKEN) && strchr(fullref.buf, '/')) {
 493                         warning("ignoring broken ref %s.", fullref.buf);
 494                 }
 495         }
 496         strbuf_release(&fullref);
 497         return refs_found;
 498 }
 499
 500 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 501 {
 502         char *last_branch = substitute_branch_name(&str, &len);
 503         const char **p;
 504         int logs_found = 0;
 505         struct strbuf path = STRBUF_INIT;
 506
 507         *log = NULL;
 508         for (p = ref_rev_parse_rules; *p; p++) {
 509                 unsigned char hash[20];
 510                 const char *ref, *it;
 511
 512                 strbuf_reset(&path);
 513                 strbuf_addf(&path, *p, len, str);
 514                 ref = resolve_ref_unsafe(path.buf, RESOLVE_REF_READING,
 515                                          hash, NULL);
 516                 if (!ref)
 517                         continue;
 518                 if (reflog_exists(path.buf))
 519                         it = path.buf;
 520                 else if (strcmp(ref, path.buf) && reflog_exists(ref))
 521                         it = ref;
 522                 else
 523                         continue;
 524                 if (!logs_found++) {
 525                         *log = xstrdup(it);
 526                         hashcpy(sha1, hash);
 527                 }
 528                 if (!warn_ambiguous_refs)
 529                         break;
 530         }
 531         strbuf_release(&path);
 532         free(last_branch);
 533         return logs_found;
 534 }
 535
 536 static int is_per_worktree_ref(const char *refname)
 537 {
 538         return !strcmp(refname, "HEAD") ||
 539                 starts_with(refname, "refs/bisect/");
 540 }
 541
 542 static int is_pseudoref_syntax(const char *refname)
 543 {
 544         const char *c;
 545
 546         for (c = refname; *c; c++) {
 547                 if (!isupper(*c) && *c != '-' && *c != '_')
 548                         return 0;
 549         }
 550
 551         return 1;
 552 }
 553
 554 enum ref_type ref_type(const char *refname)
 555 {
 556         if (is_per_worktree_ref(refname))
 557                 return REF_TYPE_PER_WORKTREE;
 558         if (is_pseudoref_syntax(refname))
 559                 return REF_TYPE_PSEUDOREF;
 560        return REF_TYPE_NORMAL;
 561 }
 562
 563 static int write_pseudoref(const char *pseudoref, const unsigned char *sha1,
 564                            const unsigned char *old_sha1, struct strbuf *err)
 565 {
 566         const char *filename;
 567         int fd;
 568         static struct lock_file lock;
 569         struct strbuf buf = STRBUF_INIT;
 570         int ret = -1;
 571
 572         strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
 573
 574         filename = git_path("%s", pseudoref);
 575         fd = hold_lock_file_for_update(&lock, filename, LOCK_DIE_ON_ERROR);
 576         if (fd < 0) {
 577                 strbuf_addf(err, "could not open '%s' for writing: %s",
 578                             filename, strerror(errno));
 579                 return -1;
 580         }
 581
 582         if (old_sha1) {
 583                 unsigned char actual_old_sha1[20];
 584
 585                 if (read_ref(pseudoref, actual_old_sha1))
 586                         die("could not read ref '%s'", pseudoref);
 587                 if (hashcmp(actual_old_sha1, old_sha1)) {
 588                         strbuf_addf(err, "unexpected sha1 when writing '%s'", pseudoref);
 589                         rollback_lock_file(&lock);
 590                         goto done;
 591                 }
 592         }
 593
 594         if (write_in_full(fd, buf.buf, buf.len) != buf.len) {
 595                 strbuf_addf(err, "could not write to '%s'", filename);
 596                 rollback_lock_file(&lock);
 597                 goto done;
 598         }
 599
 600         commit_lock_file(&lock);
 601         ret = 0;
 602 done:
 603         strbuf_release(&buf);
 604         return ret;
 605 }
 606
 607 static int delete_pseudoref(const char *pseudoref, const unsigned char *old_sha1)
 608 {
 609         static struct lock_file lock;
 610         const char *filename;
 611
 612         filename = git_path("%s", pseudoref);
 613
 614         if (old_sha1 && !is_null_sha1(old_sha1)) {
 615                 int fd;
 616                 unsigned char actual_old_sha1[20];
 617
 618                 fd = hold_lock_file_for_update(&lock, filename,
 619                                                LOCK_DIE_ON_ERROR);
 620                 if (fd < 0)
 621                         die_errno(_("Could not open '%s' for writing"), filename);
 622                 if (read_ref(pseudoref, actual_old_sha1))
 623                         die("could not read ref '%s'", pseudoref);
 624                 if (hashcmp(actual_old_sha1, old_sha1)) {
 625                         warning("Unexpected sha1 when deleting %s", pseudoref);
 626                         rollback_lock_file(&lock);
 627                         return -1;
 628                 }
 629
 630                 unlink(filename);
 631                 rollback_lock_file(&lock);
 632         } else {
 633                 unlink(filename);
 634         }
 635
 636         return 0;
 637 }
 638
 639 int refs_delete_ref(struct ref_store *refs, const char *msg,
 640                     const char *refname,
 641                     const unsigned char *old_sha1,
 642                     unsigned int flags)
 643 {
 644         struct ref_transaction *transaction;
 645         struct strbuf err = STRBUF_INIT;
 646
 647         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
 648                 assert(refs == get_main_ref_store());
 649                 return delete_pseudoref(refname, old_sha1);
 650         }
 651
 652         transaction = ref_store_transaction_begin(refs, &err);
 653         if (!transaction ||
 654             ref_transaction_delete(transaction, refname, old_sha1,
 655                                    flags, msg, &err) ||
 656             ref_transaction_commit(transaction, &err)) {
 657                 error("%s", err.buf);
 658                 ref_transaction_free(transaction);
 659                 strbuf_release(&err);
 660                 return 1;
 661         }
 662         ref_transaction_free(transaction);
 663         strbuf_release(&err);
 664         return 0;
 665 }
 666
 667 int delete_ref(const char *msg, const char *refname,
 668                const unsigned char *old_sha1, unsigned int flags)
 669 {
 670         return refs_delete_ref(get_main_ref_store(), msg, refname,
 671                                old_sha1, flags);
 672 }
 673
 674 int copy_reflog_msg(char *buf, const char *msg)
 675 {
 676         char *cp = buf;
 677         char c;
 678         int wasspace = 1;
 679
 680         *cp++ = '\t';
 681         while ((c = *msg++)) {
 682                 if (wasspace && isspace(c))
 683                         continue;
 684                 wasspace = isspace(c);
 685                 if (wasspace)
 686                         c = ' ';
 687                 *cp++ = c;
 688         }
 689         while (buf < cp && isspace(cp[-1]))
 690                 cp--;
 691         *cp++ = '\n';
 692         return cp - buf;
 693 }
 694
 695 int should_autocreate_reflog(const char *refname)
 696 {
 697         switch (log_all_ref_updates) {
 698         case LOG_REFS_ALWAYS:
 699                 return 1;
 700         case LOG_REFS_NORMAL:
 701                 return starts_with(refname, "refs/heads/") ||
 702                         starts_with(refname, "refs/remotes/") ||
 703                         starts_with(refname, "refs/notes/") ||
 704                         !strcmp(refname, "HEAD");
 705         default:
 706                 return 0;
 707         }
 708 }
 709
 710 int is_branch(const char *refname)
 711 {
 712         return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
 713 }
 714
 715 struct read_ref_at_cb {
 716         const char *refname;
 717         timestamp_t at_time;
 718         int cnt;
 719         int reccnt;
 720         unsigned char *sha1;
 721         int found_it;
 722
 723         unsigned char osha1[20];
 724         unsigned char nsha1[20];
 725         int tz;
 726         timestamp_t date;
 727         char **msg;
 728         timestamp_t *cutoff_time;
 729         int *cutoff_tz;
 730         int *cutoff_cnt;
 731 };
 732
 733 static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
 734                 const char *email, timestamp_t timestamp, int tz,
 735                 const char *message, void *cb_data)
 736 {
 737         struct read_ref_at_cb *cb = cb_data;
 738
 739         cb->reccnt++;
 740         cb->tz = tz;
 741         cb->date = timestamp;
 742
 743         if (timestamp <= cb->at_time || cb->cnt == 0) {
 744                 if (cb->msg)
 745                         *cb->msg = xstrdup(message);
 746                 if (cb->cutoff_time)
 747                         *cb->cutoff_time = timestamp;
 748                 if (cb->cutoff_tz)
 749                         *cb->cutoff_tz = tz;
 750                 if (cb->cutoff_cnt)
 751                         *cb->cutoff_cnt = cb->reccnt - 1;
 752                 /*
 753                  * we have not yet updated cb->[n|o]sha1 so they still
 754                  * hold the values for the previous record.
 755                  */
 756                 if (!is_null_sha1(cb->osha1)) {
 757                         hashcpy(cb->sha1, noid->hash);
 758                         if (hashcmp(cb->osha1, noid->hash))
 759                                 warning("Log for ref %s has gap after %s.",
 760                                         cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
 761                 }
 762                 else if (cb->date == cb->at_time)
 763                         hashcpy(cb->sha1, noid->hash);
 764                 else if (hashcmp(noid->hash, cb->sha1))
 765                         warning("Log for ref %s unexpectedly ended on %s.",
 766                                 cb->refname, show_date(cb->date, cb->tz,
 767                                                        DATE_MODE(RFC2822)));
 768                 hashcpy(cb->osha1, ooid->hash);
 769                 hashcpy(cb->nsha1, noid->hash);
 770                 cb->found_it = 1;
 771                 return 1;
 772         }
 773         hashcpy(cb->osha1, ooid->hash);
 774         hashcpy(cb->nsha1, noid->hash);
 775         if (cb->cnt > 0)
 776                 cb->cnt--;
 777         return 0;
 778 }
 779
 780 static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
 781                                   const char *email, timestamp_t timestamp,
 782                                   int tz, const char *message, void *cb_data)
 783 {
 784         struct read_ref_at_cb *cb = cb_data;
 785
 786         if (cb->msg)
 787                 *cb->msg = xstrdup(message);
 788         if (cb->cutoff_time)
 789                 *cb->cutoff_time = timestamp;
 790         if (cb->cutoff_tz)
 791                 *cb->cutoff_tz = tz;
 792         if (cb->cutoff_cnt)
 793                 *cb->cutoff_cnt = cb->reccnt;
 794         hashcpy(cb->sha1, ooid->hash);
 795         if (is_null_sha1(cb->sha1))
 796                 hashcpy(cb->sha1, noid->hash);
 797         /* We just want the first entry */
 798         return 1;
 799 }
 800
 801 int read_ref_at(const char *refname, unsigned int flags, timestamp_t at_time, int cnt,
 802                 unsigned char *sha1, char **msg,
 803                 timestamp_t *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
 804 {
 805         struct read_ref_at_cb cb;
 806
 807         memset(&cb, 0, sizeof(cb));
 808         cb.refname = refname;
 809         cb.at_time = at_time;
 810         cb.cnt = cnt;
 811         cb.msg = msg;
 812         cb.cutoff_time = cutoff_time;
 813         cb.cutoff_tz = cutoff_tz;
 814         cb.cutoff_cnt = cutoff_cnt;
 815         cb.sha1 = sha1;
 816
 817         for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
 818
 819         if (!cb.reccnt) {
 820                 if (flags & GET_SHA1_QUIETLY)
 821                         exit(128);
 822                 else
 823                         die("Log for %s is empty.", refname);
 824         }
 825         if (cb.found_it)
 826                 return 0;
 827
 828         for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
 829
 830         return 1;
 831 }
 832
 833 struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
 834                                                     struct strbuf *err)
 835 {
 836         struct ref_transaction *tr;
 837         assert(err);
 838
 839         tr = xcalloc(1, sizeof(struct ref_transaction));
 840         tr->ref_store = refs;
 841         return tr;
 842 }
 843
 844 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 845 {
 846         return ref_store_transaction_begin(get_main_ref_store(), err);
 847 }
 848
 849 void ref_transaction_free(struct ref_transaction *transaction)
 850 {
 851         size_t i;
 852
 853         if (!transaction)
 854                 return;
 855
 856         switch (transaction->state) {
 857         case REF_TRANSACTION_OPEN:
 858         case REF_TRANSACTION_CLOSED:
 859                 /* OK */
 860                 break;
 861         case REF_TRANSACTION_PREPARED:
 862                 die("BUG: free called on a prepared reference transaction");
 863                 break;
 864         default:
 865                 die("BUG: unexpected reference transaction state");
 866                 break;
 867         }
 868
 869         for (i = 0; i < transaction->nr; i++) {
 870                 free(transaction->updates[i]->msg);
 871                 free(transaction->updates[i]);
 872         }
 873         free(transaction->updates);
 874         free(transaction);
 875 }
 876
 877 struct ref_update *ref_transaction_add_update(
 878                 struct ref_transaction *transaction,
 879                 const char *refname, unsigned int flags,
 880                 const unsigned char *new_sha1,
 881                 const unsigned char *old_sha1,
 882                 const char *msg)
 883 {
 884         struct ref_update *update;
 885
 886         if (transaction->state != REF_TRANSACTION_OPEN)
 887                 die("BUG: update called for transaction that is not open");
 888
 889         if ((flags & REF_ISPRUNING) && !(flags & REF_NODEREF))
 890                 die("BUG: REF_ISPRUNING set without REF_NODEREF");
 891
 892         FLEX_ALLOC_STR(update, refname, refname);
 893         ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
 894         transaction->updates[transaction->nr++] = update;
 895
 896         update->flags = flags;
 897
 898         if (flags & REF_HAVE_NEW)
 899                 hashcpy(update->new_oid.hash, new_sha1);
 900         if (flags & REF_HAVE_OLD)
 901                 hashcpy(update->old_oid.hash, old_sha1);
 902         update->msg = xstrdup_or_null(msg);
 903         return update;
 904 }
 905
 906 int ref_transaction_update(struct ref_transaction *transaction,
 907                            const char *refname,
 908                            const unsigned char *new_sha1,
 909                            const unsigned char *old_sha1,
 910                            unsigned int flags, const char *msg,
 911                            struct strbuf *err)
 912 {
 913         assert(err);
 914
 915         if ((new_sha1 && !is_null_sha1(new_sha1)) ?
 916             check_refname_format(refname, REFNAME_ALLOW_ONELEVEL) :
 917             !refname_is_safe(refname)) {
 918                 strbuf_addf(err, "refusing to update ref with bad name '%s'",
 919                             refname);
 920                 return -1;
 921         }
 922
 923         flags |= (new_sha1 ? REF_HAVE_NEW : 0) | (old_sha1 ? REF_HAVE_OLD : 0);
 924
 925         ref_transaction_add_update(transaction, refname, flags,
 926                                    new_sha1, old_sha1, msg);
 927         return 0;
 928 }
 929
 930 int ref_transaction_create(struct ref_transaction *transaction,
 931                            const char *refname,
 932                            const unsigned char *new_sha1,
 933                            unsigned int flags, const char *msg,
 934                            struct strbuf *err)
 935 {
 936         if (!new_sha1 || is_null_sha1(new_sha1))
 937                 die("BUG: create called without valid new_sha1");
 938         return ref_transaction_update(transaction, refname, new_sha1,
 939                                       null_sha1, flags, msg, err);
 940 }
 941
 942 int ref_transaction_delete(struct ref_transaction *transaction,
 943                            const char *refname,
 944                            const unsigned char *old_sha1,
 945                            unsigned int flags, const char *msg,
 946                            struct strbuf *err)
 947 {
 948         if (old_sha1 && is_null_sha1(old_sha1))
 949                 die("BUG: delete called with old_sha1 set to zeros");
 950         return ref_transaction_update(transaction, refname,
 951                                       null_sha1, old_sha1,
 952                                       flags, msg, err);
 953 }
 954
 955 int ref_transaction_verify(struct ref_transaction *transaction,
 956                            const char *refname,
 957                            const unsigned char *old_sha1,
 958                            unsigned int flags,
 959                            struct strbuf *err)
 960 {
 961         if (!old_sha1)
 962                 die("BUG: verify called with old_sha1 set to NULL");
 963         return ref_transaction_update(transaction, refname,
 964                                       NULL, old_sha1,
 965                                       flags, NULL, err);
 966 }
 967
 968 int update_ref_oid(const char *msg, const char *refname,
 969                const struct object_id *new_oid, const struct object_id *old_oid,
 970                unsigned int flags, enum action_on_err onerr)
 971 {
 972         return update_ref(msg, refname, new_oid ? new_oid->hash : NULL,
 973                 old_oid ? old_oid->hash : NULL, flags, onerr);
 974 }
 975
 976 int refs_update_ref(struct ref_store *refs, const char *msg,
 977                     const char *refname, const unsigned char *new_sha1,
 978                     const unsigned char *old_sha1, unsigned int flags,
 979                     enum action_on_err onerr)
 980 {
 981         struct ref_transaction *t = NULL;
 982         struct strbuf err = STRBUF_INIT;
 983         int ret = 0;
 984
 985         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
 986                 assert(refs == get_main_ref_store());
 987                 ret = write_pseudoref(refname, new_sha1, old_sha1, &err);
 988         } else {
 989                 t = ref_store_transaction_begin(refs, &err);
 990                 if (!t ||
 991                     ref_transaction_update(t, refname, new_sha1, old_sha1,
 992                                            flags, msg, &err) ||
 993                     ref_transaction_commit(t, &err)) {
 994                         ret = 1;
 995                         ref_transaction_free(t);
 996                 }
 997         }
 998         if (ret) {
 999                 const char *str = "update_ref failed for ref '%s': %s";
1000
1001                 switch (onerr) {
1002                 case UPDATE_REFS_MSG_ON_ERR:
1003                         error(str, refname, err.buf);
1004                         break;
1005                 case UPDATE_REFS_DIE_ON_ERR:
1006                         die(str, refname, err.buf);
1007                         break;
1008                 case UPDATE_REFS_QUIET_ON_ERR:
1009                         break;
1010                 }
1011                 strbuf_release(&err);
1012                 return 1;
1013         }
1014         strbuf_release(&err);
1015         if (t)
1016                 ref_transaction_free(t);
1017         return 0;
1018 }
1019
1020 int update_ref(const char *msg, const char *refname,
1021                const unsigned char *new_sha1,
1022                const unsigned char *old_sha1,
1023                unsigned int flags, enum action_on_err onerr)
1024 {
1025         return refs_update_ref(get_main_ref_store(), msg, refname, new_sha1,
1026                                old_sha1, flags, onerr);
1027 }
1028
1029 char *shorten_unambiguous_ref(const char *refname, int strict)
1030 {
1031         int i;
1032         static char **scanf_fmts;
1033         static int nr_rules;
1034         char *short_name;
1035         struct strbuf resolved_buf = STRBUF_INIT;
1036
1037         if (!nr_rules) {
1038                 /*
1039                  * Pre-generate scanf formats from ref_rev_parse_rules[].
1040                  * Generate a format suitable for scanf from a
1041                  * ref_rev_parse_rules rule by interpolating "%s" at the
1042                  * location of the "%.*s".
1043                  */
1044                 size_t total_len = 0;
1045                 size_t offset = 0;
1046
1047                 /* the rule list is NULL terminated, count them first */
1048                 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
1049                         /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
1050                         total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
1051
1052                 scanf_fmts = xmalloc(st_add(st_mult(sizeof(char *), nr_rules), total_len));
1053
1054                 offset = 0;
1055                 for (i = 0; i < nr_rules; i++) {
1056                         assert(offset < total_len);
1057                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
1058                         offset += snprintf(scanf_fmts[i], total_len - offset,
1059                                            ref_rev_parse_rules[i], 2, "%s") + 1;
1060                 }
1061         }
1062
1063         /* bail out if there are no rules */
1064         if (!nr_rules)
1065                 return xstrdup(refname);
1066
1067         /* buffer for scanf result, at most refname must fit */
1068         short_name = xstrdup(refname);
1069
1070         /* skip first rule, it will always match */
1071         for (i = nr_rules - 1; i > 0 ; --i) {
1072                 int j;
1073                 int rules_to_fail = i;
1074                 int short_name_len;
1075
1076                 if (1 != sscanf(refname, scanf_fmts[i], short_name))
1077                         continue;
1078
1079                 short_name_len = strlen(short_name);
1080
1081                 /*
1082                  * in strict mode, all (except the matched one) rules
1083                  * must fail to resolve to a valid non-ambiguous ref
1084                  */
1085                 if (strict)
1086                         rules_to_fail = nr_rules;
1087
1088                 /*
1089                  * check if the short name resolves to a valid ref,
1090                  * but use only rules prior to the matched one
1091                  */
1092                 for (j = 0; j < rules_to_fail; j++) {
1093                         const char *rule = ref_rev_parse_rules[j];
1094
1095                         /* skip matched rule */
1096                         if (i == j)
1097                                 continue;
1098
1099                         /*
1100                          * the short name is ambiguous, if it resolves
1101                          * (with this previous rule) to a valid ref
1102                          * read_ref() returns 0 on success
1103                          */
1104                         strbuf_reset(&resolved_buf);
1105                         strbuf_addf(&resolved_buf, rule,
1106                                     short_name_len, short_name);
1107                         if (ref_exists(resolved_buf.buf))
1108                                 break;
1109                 }
1110
1111                 /*
1112                  * short name is non-ambiguous if all previous rules
1113                  * haven't resolved to a valid ref
1114                  */
1115                 if (j == rules_to_fail) {
1116                         strbuf_release(&resolved_buf);
1117                         return short_name;
1118                 }
1119         }
1120
1121         strbuf_release(&resolved_buf);
1122         free(short_name);
1123         return xstrdup(refname);
1124 }
1125
1126 static struct string_list *hide_refs;
1127
1128 int parse_hide_refs_config(const char *var, const char *value, const char *section)
1129 {
1130         const char *key;
1131         if (!strcmp("transfer.hiderefs", var) ||
1132             (!parse_config_key(var, section, NULL, NULL, &key) &&
1133              !strcmp(key, "hiderefs"))) {
1134                 char *ref;
1135                 int len;
1136
1137                 if (!value)
1138                         return config_error_nonbool(var);
1139                 ref = xstrdup(value);
1140                 len = strlen(ref);
1141                 while (len && ref[len - 1] == '/')
1142                         ref[--len] = '\0';
1143                 if (!hide_refs) {
1144                         hide_refs = xcalloc(1, sizeof(*hide_refs));
1145                         hide_refs->strdup_strings = 1;
1146                 }
1147                 string_list_append(hide_refs, ref);
1148         }
1149         return 0;
1150 }
1151
1152 int ref_is_hidden(const char *refname, const char *refname_full)
1153 {
1154         int i;
1155
1156         if (!hide_refs)
1157                 return 0;
1158         for (i = hide_refs->nr - 1; i >= 0; i--) {
1159                 const char *match = hide_refs->items[i].string;
1160                 const char *subject;
1161                 int neg = 0;
1162                 int len;
1163
1164                 if (*match == '!') {
1165                         neg = 1;
1166                         match++;
1167                 }
1168
1169                 if (*match == '^') {
1170                         subject = refname_full;
1171                         match++;
1172                 } else {
1173                         subject = refname;
1174                 }
1175
1176                 /* refname can be NULL when namespaces are used. */
1177                 if (!subject || !starts_with(subject, match))
1178                         continue;
1179                 len = strlen(match);
1180                 if (!subject[len] || subject[len] == '/')
1181                         return !neg;
1182         }
1183         return 0;
1184 }
1185
1186 const char *find_descendant_ref(const char *dirname,
1187                                 const struct string_list *extras,
1188                                 const struct string_list *skip)
1189 {
1190         int pos;
1191
1192         if (!extras)
1193                 return NULL;
1194
1195         /*
1196          * Look at the place where dirname would be inserted into
1197          * extras. If there is an entry at that position that starts
1198          * with dirname (remember, dirname includes the trailing
1199          * slash) and is not in skip, then we have a conflict.
1200          */
1201         for (pos = string_list_find_insert_index(extras, dirname, 0);
1202              pos < extras->nr; pos++) {
1203                 const char *extra_refname = extras->items[pos].string;
1204
1205                 if (!starts_with(extra_refname, dirname))
1206                         break;
1207
1208                 if (!skip || !string_list_has_string(skip, extra_refname))
1209                         return extra_refname;
1210         }
1211         return NULL;
1212 }
1213
1214 int refs_rename_ref_available(struct ref_store *refs,
1215                               const char *old_refname,
1216                               const char *new_refname)
1217 {
1218         struct string_list skip = STRING_LIST_INIT_NODUP;
1219         struct strbuf err = STRBUF_INIT;
1220         int ok;
1221
1222         string_list_insert(&skip, old_refname);
1223         ok = !refs_verify_refname_available(refs, new_refname,
1224                                             NULL, &skip, &err);
1225         if (!ok)
1226                 error("%s", err.buf);
1227
1228         string_list_clear(&skip, 0);
1229         strbuf_release(&err);
1230         return ok;
1231 }
1232
1233 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1234 {
1235         struct object_id oid;
1236         int flag;
1237
1238         if (submodule) {
1239                 if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
1240                         return fn("HEAD", &oid, 0, cb_data);
1241
1242                 return 0;
1243         }
1244
1245         if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
1246                 return fn("HEAD", &oid, flag, cb_data);
1247
1248         return 0;
1249 }
1250
1251 int head_ref(each_ref_fn fn, void *cb_data)
1252 {
1253         return head_ref_submodule(NULL, fn, cb_data);
1254 }
1255
1256 struct ref_iterator *refs_ref_iterator_begin(
1257                 struct ref_store *refs,
1258                 const char *prefix, int trim, int flags)
1259 {
1260         struct ref_iterator *iter;
1261
1262         if (ref_paranoia < 0)
1263                 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1264         if (ref_paranoia)
1265                 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1266
1267         iter = refs->be->iterator_begin(refs, prefix, flags);
1268
1269         /*
1270          * `iterator_begin()` already takes care of prefix, but we
1271          * might need to do some trimming:
1272          */
1273         if (trim)
1274                 iter = prefix_ref_iterator_begin(iter, "", trim);
1275
1276         return iter;
1277 }
1278
1279 /*
1280  * Call fn for each reference in the specified submodule for which the
1281  * refname begins with prefix. If trim is non-zero, then trim that
1282  * many characters off the beginning of each refname before passing
1283  * the refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to
1284  * include broken references in the iteration. If fn ever returns a
1285  * non-zero value, stop the iteration and return that value;
1286  * otherwise, return 0.
1287  */
1288 static int do_for_each_ref(struct ref_store *refs, const char *prefix,
1289                            each_ref_fn fn, int trim, int flags, void *cb_data)
1290 {
1291         struct ref_iterator *iter;
1292
1293         if (!refs)
1294                 return 0;
1295
1296         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1297
1298         return do_for_each_ref_iterator(iter, fn, cb_data);
1299 }
1300
1301 int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1302 {
1303         return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
1304 }
1305
1306 int for_each_ref(each_ref_fn fn, void *cb_data)
1307 {
1308         return refs_for_each_ref(get_main_ref_store(), fn, cb_data);
1309 }
1310
1311 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1312 {
1313         return refs_for_each_ref(get_submodule_ref_store(submodule), fn, cb_data);
1314 }
1315
1316 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
1317                          each_ref_fn fn, void *cb_data)
1318 {
1319         return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
1320 }
1321
1322 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1323 {
1324         return refs_for_each_ref_in(get_main_ref_store(), prefix, fn, cb_data);
1325 }
1326
1327 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1328 {
1329         unsigned int flag = 0;
1330
1331         if (broken)
1332                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1333         return do_for_each_ref(get_main_ref_store(),
1334                                prefix, fn, 0, flag, cb_data);
1335 }
1336
1337 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1338                               each_ref_fn fn, void *cb_data)
1339 {
1340         return refs_for_each_ref_in(get_submodule_ref_store(submodule),
1341                                     prefix, fn, cb_data);
1342 }
1343
1344 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1345 {
1346         return do_for_each_ref(get_main_ref_store(),
1347                                git_replace_ref_base, fn,
1348                                strlen(git_replace_ref_base),
1349                                0, cb_data);
1350 }
1351
1352 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1353 {
1354         struct strbuf buf = STRBUF_INIT;
1355         int ret;
1356         strbuf_addf(&buf, "%srefs/", get_git_namespace());
1357         ret = do_for_each_ref(get_main_ref_store(),
1358                               buf.buf, fn, 0, 0, cb_data);
1359         strbuf_release(&buf);
1360         return ret;
1361 }
1362
1363 int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1364 {
1365         return do_for_each_ref(refs, "", fn, 0,
1366                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1367 }
1368
1369 int for_each_rawref(each_ref_fn fn, void *cb_data)
1370 {
1371         return refs_for_each_rawref(get_main_ref_store(), fn, cb_data);
1372 }
1373
1374 int refs_read_raw_ref(struct ref_store *ref_store,
1375                       const char *refname, unsigned char *sha1,
1376                       struct strbuf *referent, unsigned int *type)
1377 {
1378         return ref_store->be->read_raw_ref(ref_store, refname, sha1, referent, type);
1379 }
1380
1381 /* This function needs to return a meaningful errno on failure */
1382 const char *refs_resolve_ref_unsafe(struct ref_store *refs,
1383                                     const char *refname,
1384                                     int resolve_flags,
1385                                     unsigned char *sha1, int *flags)
1386 {
1387         static struct strbuf sb_refname = STRBUF_INIT;
1388         int unused_flags;
1389         int symref_count;
1390
1391         if (!flags)
1392                 flags = &unused_flags;
1393
1394         *flags = 0;
1395
1396         if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1397                 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1398                     !refname_is_safe(refname)) {
1399                         errno = EINVAL;
1400                         return NULL;
1401                 }
1402
1403                 /*
1404                  * dwim_ref() uses REF_ISBROKEN to distinguish between
1405                  * missing refs and refs that were present but invalid,
1406                  * to complain about the latter to stderr.
1407                  *
1408                  * We don't know whether the ref exists, so don't set
1409                  * REF_ISBROKEN yet.
1410                  */
1411                 *flags |= REF_BAD_NAME;
1412         }
1413
1414         for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
1415                 unsigned int read_flags = 0;
1416
1417                 if (refs_read_raw_ref(refs, refname,
1418                                       sha1, &sb_refname, &read_flags)) {
1419                         *flags |= read_flags;
1420                         if (errno != ENOENT || (resolve_flags & RESOLVE_REF_READING))
1421                                 return NULL;
1422                         hashclr(sha1);
1423                         if (*flags & REF_BAD_NAME)
1424                                 *flags |= REF_ISBROKEN;
1425                         return refname;
1426                 }
1427
1428                 *flags |= read_flags;
1429
1430                 if (!(read_flags & REF_ISSYMREF)) {
1431                         if (*flags & REF_BAD_NAME) {
1432                                 hashclr(sha1);
1433                                 *flags |= REF_ISBROKEN;
1434                         }
1435                         return refname;
1436                 }
1437
1438                 refname = sb_refname.buf;
1439                 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1440                         hashclr(sha1);
1441                         return refname;
1442                 }
1443                 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1444                         if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1445                             !refname_is_safe(refname)) {
1446                                 errno = EINVAL;
1447                                 return NULL;
1448                         }
1449
1450                         *flags |= REF_ISBROKEN | REF_BAD_NAME;
1451                 }
1452         }
1453
1454         errno = ELOOP;
1455         return NULL;
1456 }
1457
1458 /* backend functions */
1459 int refs_init_db(struct strbuf *err)
1460 {
1461         struct ref_store *refs = get_main_ref_store();
1462
1463         return refs->be->init_db(refs, err);
1464 }
1465
1466 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1467                                unsigned char *sha1, int *flags)
1468 {
1469         return refs_resolve_ref_unsafe(get_main_ref_store(), refname,
1470                                        resolve_flags, sha1, flags);
1471 }
1472
1473 int resolve_gitlink_ref(const char *submodule, const char *refname,
1474                         unsigned char *sha1)
1475 {
1476         size_t len = strlen(submodule);
1477         struct ref_store *refs;
1478         int flags;
1479
1480         while (len && submodule[len - 1] == '/')
1481                 len--;
1482
1483         if (!len)
1484                 return -1;
1485
1486         if (submodule[len]) {
1487                 /* We need to strip off one or more trailing slashes */
1488                 char *stripped = xmemdupz(submodule, len);
1489
1490                 refs = get_submodule_ref_store(stripped);
1491                 free(stripped);
1492         } else {
1493                 refs = get_submodule_ref_store(submodule);
1494         }
1495
1496         if (!refs)
1497                 return -1;
1498
1499         if (!refs_resolve_ref_unsafe(refs, refname, 0, sha1, &flags) ||
1500             is_null_sha1(sha1))
1501                 return -1;
1502         return 0;
1503 }
1504
1505 struct ref_store_hash_entry
1506 {
1507         struct hashmap_entry ent; /* must be the first member! */
1508
1509         struct ref_store *refs;
1510
1511         /* NUL-terminated identifier of the ref store: */
1512         char name[FLEX_ARRAY];
1513 };
1514
1515 static int ref_store_hash_cmp(const void *entry, const void *entry_or_key,
1516                               const void *keydata)
1517 {
1518         const struct ref_store_hash_entry *e1 = entry, *e2 = entry_or_key;
1519         const char *name = keydata ? keydata : e2->name;
1520
1521         return strcmp(e1->name, name);
1522 }
1523
1524 static struct ref_store_hash_entry *alloc_ref_store_hash_entry(
1525                 const char *name, struct ref_store *refs)
1526 {
1527         struct ref_store_hash_entry *entry;
1528
1529         FLEX_ALLOC_STR(entry, name, name);
1530         hashmap_entry_init(entry, strhash(name));
1531         entry->refs = refs;
1532         return entry;
1533 }
1534
1535 /* A pointer to the ref_store for the main repository: */
1536 static struct ref_store *main_ref_store;
1537
1538 /* A hashmap of ref_stores, stored by submodule name: */
1539 static struct hashmap submodule_ref_stores;
1540
1541 /* A hashmap of ref_stores, stored by worktree id: */
1542 static struct hashmap worktree_ref_stores;
1543
1544 /*
1545  * Look up a ref store by name. If that ref_store hasn't been
1546  * registered yet, return NULL.
1547  */
1548 static struct ref_store *lookup_ref_store_map(struct hashmap *map,
1549                                               const char *name)
1550 {
1551         struct ref_store_hash_entry *entry;
1552
1553         if (!map->tablesize)
1554                 /* It's initialized on demand in register_ref_store(). */
1555                 return NULL;
1556
1557         entry = hashmap_get_from_hash(map, strhash(name), name);
1558         return entry ? entry->refs : NULL;
1559 }
1560
1561 /*
1562  * Create, record, and return a ref_store instance for the specified
1563  * gitdir.
1564  */
1565 static struct ref_store *ref_store_init(const char *gitdir,
1566                                         unsigned int flags)
1567 {
1568         const char *be_name = "files";
1569         struct ref_storage_be *be = find_ref_storage_backend(be_name);
1570         struct ref_store *refs;
1571
1572         if (!be)
1573                 die("BUG: reference backend %s is unknown", be_name);
1574
1575         refs = be->init(gitdir, flags);
1576         return refs;
1577 }
1578
1579 struct ref_store *get_main_ref_store(void)
1580 {
1581         if (main_ref_store)
1582                 return main_ref_store;
1583
1584         main_ref_store = ref_store_init(get_git_dir(), REF_STORE_ALL_CAPS);
1585         return main_ref_store;
1586 }
1587
1588 /*
1589  * Associate a ref store with a name. It is a fatal error to call this
1590  * function twice for the same name.
1591  */
1592 static void register_ref_store_map(struct hashmap *map,
1593                                    const char *type,
1594                                    struct ref_store *refs,
1595                                    const char *name)
1596 {
1597         if (!map->tablesize)
1598                 hashmap_init(map, ref_store_hash_cmp, 0);
1599
1600         if (hashmap_put(map, alloc_ref_store_hash_entry(name, refs)))
1601                 die("BUG: %s ref_store '%s' initialized twice", type, name);
1602 }
1603
1604 struct ref_store *get_submodule_ref_store(const char *submodule)
1605 {
1606         struct strbuf submodule_sb = STRBUF_INIT;
1607         struct ref_store *refs;
1608         int ret;
1609
1610         if (!submodule || !*submodule) {
1611                 /*
1612                  * FIXME: This case is ideally not allowed. But that
1613                  * can't happen until we clean up all the callers.
1614                  */
1615                 return get_main_ref_store();
1616         }
1617
1618         refs = lookup_ref_store_map(&submodule_ref_stores, submodule);
1619         if (refs)
1620                 return refs;
1621
1622         strbuf_addstr(&submodule_sb, submodule);
1623         ret = is_nonbare_repository_dir(&submodule_sb);
1624         strbuf_release(&submodule_sb);
1625         if (!ret)
1626                 return NULL;
1627
1628         ret = submodule_to_gitdir(&submodule_sb, submodule);
1629         if (ret) {
1630                 strbuf_release(&submodule_sb);
1631                 return NULL;
1632         }
1633
1634         /* assume that add_submodule_odb() has been called */
1635         refs = ref_store_init(submodule_sb.buf,
1636                               REF_STORE_READ | REF_STORE_ODB);
1637         register_ref_store_map(&submodule_ref_stores, "submodule",
1638                                refs, submodule);
1639
1640         strbuf_release(&submodule_sb);
1641         return refs;
1642 }
1643
1644 struct ref_store *get_worktree_ref_store(const struct worktree *wt)
1645 {
1646         struct ref_store *refs;
1647         const char *id;
1648
1649         if (wt->is_current)
1650                 return get_main_ref_store();
1651
1652         id = wt->id ? wt->id : "/";
1653         refs = lookup_ref_store_map(&worktree_ref_stores, id);
1654         if (refs)
1655                 return refs;
1656
1657         if (wt->id)
1658                 refs = ref_store_init(git_common_path("worktrees/%s", wt->id),
1659                                       REF_STORE_ALL_CAPS);
1660         else
1661                 refs = ref_store_init(get_git_common_dir(),
1662                                       REF_STORE_ALL_CAPS);
1663
1664         if (refs)
1665                 register_ref_store_map(&worktree_ref_stores, "worktree",
1666                                        refs, id);
1667         return refs;
1668 }
1669
1670 void base_ref_store_init(struct ref_store *refs,
1671                          const struct ref_storage_be *be)
1672 {
1673         refs->be = be;
1674 }
1675
1676 /* backend functions */
1677 int refs_pack_refs(struct ref_store *refs, unsigned int flags)
1678 {
1679         return refs->be->pack_refs(refs, flags);
1680 }
1681
1682 int refs_peel_ref(struct ref_store *refs, const char *refname,
1683                   unsigned char *sha1)
1684 {
1685         return refs->be->peel_ref(refs, refname, sha1);
1686 }
1687
1688 int peel_ref(const char *refname, unsigned char *sha1)
1689 {
1690         return refs_peel_ref(get_main_ref_store(), refname, sha1);
1691 }
1692
1693 int refs_create_symref(struct ref_store *refs,
1694                        const char *ref_target,
1695                        const char *refs_heads_master,
1696                        const char *logmsg)
1697 {
1698         return refs->be->create_symref(refs, ref_target,
1699                                        refs_heads_master,
1700                                        logmsg);
1701 }
1702
1703 int create_symref(const char *ref_target, const char *refs_heads_master,
1704                   const char *logmsg)
1705 {
1706         return refs_create_symref(get_main_ref_store(), ref_target,
1707                                   refs_heads_master, logmsg);
1708 }
1709
1710 int ref_update_reject_duplicates(struct string_list *refnames,
1711                                  struct strbuf *err)
1712 {
1713         size_t i, n = refnames->nr;
1714
1715         assert(err);
1716
1717         for (i = 1; i < n; i++) {
1718                 int cmp = strcmp(refnames->items[i - 1].string,
1719                                  refnames->items[i].string);
1720
1721                 if (!cmp) {
1722                         strbuf_addf(err,
1723                                     "multiple updates for ref '%s' not allowed.",
1724                                     refnames->items[i].string);
1725                         return 1;
1726                 } else if (cmp > 0) {
1727                         die("BUG: ref_update_reject_duplicates() received unsorted list");
1728                 }
1729         }
1730         return 0;
1731 }
1732
1733 int ref_transaction_prepare(struct ref_transaction *transaction,
1734                             struct strbuf *err)
1735 {
1736         struct ref_store *refs = transaction->ref_store;
1737
1738         switch (transaction->state) {
1739         case REF_TRANSACTION_OPEN:
1740                 /* Good. */
1741                 break;
1742         case REF_TRANSACTION_PREPARED:
1743                 die("BUG: prepare called twice on reference transaction");
1744                 break;
1745         case REF_TRANSACTION_CLOSED:
1746                 die("BUG: prepare called on a closed reference transaction");
1747                 break;
1748         default:
1749                 die("BUG: unexpected reference transaction state");
1750                 break;
1751         }
1752
1753         if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
1754                 strbuf_addstr(err,
1755                               _("ref updates forbidden inside quarantine environment"));
1756                 return -1;
1757         }
1758
1759         return refs->be->transaction_prepare(refs, transaction, err);
1760 }
1761
1762 int ref_transaction_abort(struct ref_transaction *transaction,
1763                           struct strbuf *err)
1764 {
1765         struct ref_store *refs = transaction->ref_store;
1766         int ret = 0;
1767
1768         switch (transaction->state) {
1769         case REF_TRANSACTION_OPEN:
1770                 /* No need to abort explicitly. */
1771                 break;
1772         case REF_TRANSACTION_PREPARED:
1773                 ret = refs->be->transaction_abort(refs, transaction, err);
1774                 break;
1775         case REF_TRANSACTION_CLOSED:
1776                 die("BUG: abort called on a closed reference transaction");
1777                 break;
1778         default:
1779                 die("BUG: unexpected reference transaction state");
1780                 break;
1781         }
1782
1783         ref_transaction_free(transaction);
1784         return ret;
1785 }
1786
1787 int ref_transaction_commit(struct ref_transaction *transaction,
1788                            struct strbuf *err)
1789 {
1790         struct ref_store *refs = transaction->ref_store;
1791         int ret;
1792
1793         switch (transaction->state) {
1794         case REF_TRANSACTION_OPEN:
1795                 /* Need to prepare first. */
1796                 ret = ref_transaction_prepare(transaction, err);
1797                 if (ret)
1798                         return ret;
1799                 break;
1800         case REF_TRANSACTION_PREPARED:
1801                 /* Fall through to finish. */
1802                 break;
1803         case REF_TRANSACTION_CLOSED:
1804                 die("BUG: commit called on a closed reference transaction");
1805                 break;
1806         default:
1807                 die("BUG: unexpected reference transaction state");
1808                 break;
1809         }
1810
1811         return refs->be->transaction_finish(refs, transaction, err);
1812 }
1813
1814 int refs_verify_refname_available(struct ref_store *refs,
1815                                   const char *refname,
1816                                   const struct string_list *extras,
1817                                   const struct string_list *skip,
1818                                   struct strbuf *err)
1819 {
1820         const char *slash;
1821         const char *extra_refname;
1822         struct strbuf dirname = STRBUF_INIT;
1823         struct strbuf referent = STRBUF_INIT;
1824         struct object_id oid;
1825         unsigned int type;
1826         struct ref_iterator *iter;
1827         int ok;
1828         int ret = -1;
1829
1830         /*
1831          * For the sake of comments in this function, suppose that
1832          * refname is "refs/foo/bar".
1833          */
1834
1835         assert(err);
1836
1837         strbuf_grow(&dirname, strlen(refname) + 1);
1838         for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
1839                 /* Expand dirname to the new prefix, not including the trailing slash: */
1840                 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
1841
1842                 /*
1843                  * We are still at a leading dir of the refname (e.g.,
1844                  * "refs/foo"; if there is a reference with that name,
1845                  * it is a conflict, *unless* it is in skip.
1846                  */
1847                 if (skip && string_list_has_string(skip, dirname.buf))
1848                         continue;
1849
1850                 if (!refs_read_raw_ref(refs, dirname.buf, oid.hash, &referent, &type)) {
1851                         strbuf_addf(err, "'%s' exists; cannot create '%s'",
1852                                     dirname.buf, refname);
1853                         goto cleanup;
1854                 }
1855
1856                 if (extras && string_list_has_string(extras, dirname.buf)) {
1857                         strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1858                                     refname, dirname.buf);
1859                         goto cleanup;
1860                 }
1861         }
1862
1863         /*
1864          * We are at the leaf of our refname (e.g., "refs/foo/bar").
1865          * There is no point in searching for a reference with that
1866          * name, because a refname isn't considered to conflict with
1867          * itself. But we still need to check for references whose
1868          * names are in the "refs/foo/bar/" namespace, because they
1869          * *do* conflict.
1870          */
1871         strbuf_addstr(&dirname, refname + dirname.len);
1872         strbuf_addch(&dirname, '/');
1873
1874         iter = refs_ref_iterator_begin(refs, dirname.buf, 0,
1875                                        DO_FOR_EACH_INCLUDE_BROKEN);
1876         while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
1877                 if (skip &&
1878                     string_list_has_string(skip, iter->refname))
1879                         continue;
1880
1881                 strbuf_addf(err, "'%s' exists; cannot create '%s'",
1882                             iter->refname, refname);
1883                 ref_iterator_abort(iter);
1884                 goto cleanup;
1885         }
1886
1887         if (ok != ITER_DONE)
1888                 die("BUG: error while iterating over references");
1889
1890         extra_refname = find_descendant_ref(dirname.buf, extras, skip);
1891         if (extra_refname)
1892                 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1893                             refname, extra_refname);
1894         else
1895                 ret = 0;
1896
1897 cleanup:
1898         strbuf_release(&referent);
1899         strbuf_release(&dirname);
1900         return ret;
1901 }
1902
1903 int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1904 {
1905         struct ref_iterator *iter;
1906
1907         iter = refs->be->reflog_iterator_begin(refs);
1908
1909         return do_for_each_ref_iterator(iter, fn, cb_data);
1910 }
1911
1912 int for_each_reflog(each_ref_fn fn, void *cb_data)
1913 {
1914         return refs_for_each_reflog(get_main_ref_store(), fn, cb_data);
1915 }
1916
1917 int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
1918                                      const char *refname,
1919                                      each_reflog_ent_fn fn,
1920                                      void *cb_data)
1921 {
1922         return refs->be->for_each_reflog_ent_reverse(refs, refname,
1923                                                      fn, cb_data);
1924 }
1925
1926 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
1927                                 void *cb_data)
1928 {
1929         return refs_for_each_reflog_ent_reverse(get_main_ref_store(),
1930                                                 refname, fn, cb_data);
1931 }
1932
1933 int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
1934                              each_reflog_ent_fn fn, void *cb_data)
1935 {
1936         return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
1937 }
1938
1939 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
1940                         void *cb_data)
1941 {
1942         return refs_for_each_reflog_ent(get_main_ref_store(), refname,
1943                                         fn, cb_data);
1944 }
1945
1946 int refs_reflog_exists(struct ref_store *refs, const char *refname)
1947 {
1948         return refs->be->reflog_exists(refs, refname);
1949 }
1950
1951 int reflog_exists(const char *refname)
1952 {
1953         return refs_reflog_exists(get_main_ref_store(), refname);
1954 }
1955
1956 int refs_create_reflog(struct ref_store *refs, const char *refname,
1957                        int force_create, struct strbuf *err)
1958 {
1959         return refs->be->create_reflog(refs, refname, force_create, err);
1960 }
1961
1962 int safe_create_reflog(const char *refname, int force_create,
1963                        struct strbuf *err)
1964 {
1965         return refs_create_reflog(get_main_ref_store(), refname,
1966                                   force_create, err);
1967 }
1968
1969 int refs_delete_reflog(struct ref_store *refs, const char *refname)
1970 {
1971         return refs->be->delete_reflog(refs, refname);
1972 }
1973
1974 int delete_reflog(const char *refname)
1975 {
1976         return refs_delete_reflog(get_main_ref_store(), refname);
1977 }
1978
1979 int refs_reflog_expire(struct ref_store *refs,
1980                        const char *refname, const unsigned char *sha1,
1981                        unsigned int flags,
1982                        reflog_expiry_prepare_fn prepare_fn,
1983                        reflog_expiry_should_prune_fn should_prune_fn,
1984                        reflog_expiry_cleanup_fn cleanup_fn,
1985                        void *policy_cb_data)
1986 {
1987         return refs->be->reflog_expire(refs, refname, sha1, flags,
1988                                        prepare_fn, should_prune_fn,
1989                                        cleanup_fn, policy_cb_data);
1990 }
1991
1992 int reflog_expire(const char *refname, const unsigned char *sha1,
1993                   unsigned int flags,
1994                   reflog_expiry_prepare_fn prepare_fn,
1995                   reflog_expiry_should_prune_fn should_prune_fn,
1996                   reflog_expiry_cleanup_fn cleanup_fn,
1997                   void *policy_cb_data)
1998 {
1999         return refs_reflog_expire(get_main_ref_store(),
2000                                   refname, sha1, flags,
2001                                   prepare_fn, should_prune_fn,
2002                                   cleanup_fn, policy_cb_data);
2003 }
2004
2005 int initial_ref_transaction_commit(struct ref_transaction *transaction,
2006                                    struct strbuf *err)
2007 {
2008         struct ref_store *refs = transaction->ref_store;
2009
2010         return refs->be->initial_transaction_commit(refs, transaction, err);
2011 }
2012
2013 int refs_delete_refs(struct ref_store *refs, const char *msg,
2014                      struct string_list *refnames, unsigned int flags)
2015 {
2016         return refs->be->delete_refs(refs, msg, refnames, flags);
2017 }
2018
2019 int delete_refs(const char *msg, struct string_list *refnames,
2020                 unsigned int flags)
2021 {
2022         return refs_delete_refs(get_main_ref_store(), msg, refnames, flags);
2023 }
2024
2025 int refs_rename_ref(struct ref_store *refs, const char *oldref,
2026                     const char *newref, const char *logmsg)
2027 {
2028         return refs->be->rename_ref(refs, oldref, newref, logmsg);
2029 }
2030
2031 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
2032 {
2033         return refs_rename_ref(get_main_ref_store(), oldref, newref, logmsg);
2034 }