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 "object.h"
  13 #include "tag.h"
  14 #include "submodule.h"
  15 #include "worktree.h"
  16
  17 /*
  18  * List of all available backends
  19  */
  20 static struct ref_storage_be *refs_backends = &refs_be_files;
  21
  22 static struct ref_storage_be *find_ref_storage_backend(const char *name)
  23 {
  24         struct ref_storage_be *be;
  25         for (be = refs_backends; be; be = be->next)
  26                 if (!strcmp(be->name, name))
  27                         return be;
  28         return NULL;
  29 }
  30
  31 int ref_storage_backend_exists(const char *name)
  32 {
  33         return find_ref_storage_backend(name) != NULL;
  34 }
  35
  36 /*
  37  * How to handle various characters in refnames:
  38  * 0: An acceptable character for refs
  39  * 1: End-of-component
  40  * 2: ., look for a preceding . to reject .. in refs
  41  * 3: {, look for a preceding @ to reject @{ in refs
  42  * 4: A bad character: ASCII control characters, and
  43  *    ":", "?", "[", "\", "^", "~", SP, or TAB
  44  * 5: *, reject unless REFNAME_REFSPEC_PATTERN is set
  45  */
  46 static unsigned char refname_disposition[256] = {
  47         1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
  48         4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
  49         4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 1,
  50         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
  51         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  52         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
  53         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  54         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
  55 };
  56
  57 /*
  58  * Try to read one refname component from the front of refname.
  59  * Return the length of the component found, or -1 if the component is
  60  * not legal.  It is legal if it is something reasonable to have under
  61  * ".git/refs/"; We do not like it if:
  62  *
  63  * - any path component of it begins with ".", or
  64  * - it has double dots "..", or
  65  * - it has ASCII control characters, or
  66  * - it has ":", "?", "[", "\", "^", "~", SP, or TAB anywhere, or
  67  * - it has "*" anywhere unless REFNAME_REFSPEC_PATTERN is set, or
  68  * - it ends with a "/", or
  69  * - it ends with ".lock", or
  70  * - it contains a "@{" portion
  71  */
  72 static int check_refname_component(const char *refname, int *flags)
  73 {
  74         const char *cp;
  75         char last = '\0';
  76
  77         for (cp = refname; ; cp++) {
  78                 int ch = *cp & 255;
  79                 unsigned char disp = refname_disposition[ch];
  80                 switch (disp) {
  81                 case 1:
  82                         goto out;
  83                 case 2:
  84                         if (last == '.')
  85                                 return -1; /* Refname contains "..". */
  86                         break;
  87                 case 3:
  88                         if (last == '@')
  89                                 return -1; /* Refname contains "@{". */
  90                         break;
  91                 case 4:
  92                         return -1;
  93                 case 5:
  94                         if (!(*flags & REFNAME_REFSPEC_PATTERN))
  95                                 return -1; /* refspec can't be a pattern */
  96
  97                         /*
  98                          * Unset the pattern flag so that we only accept
  99                          * a single asterisk for one side of refspec.
 100                          */
 101                         *flags &= ~ REFNAME_REFSPEC_PATTERN;
 102                         break;
 103                 }
 104                 last = ch;
 105         }
 106 out:
 107         if (cp == refname)
 108                 return 0; /* Component has zero length. */
 109         if (refname[0] == '.')
 110                 return -1; /* Component starts with '.'. */
 111         if (cp - refname >= LOCK_SUFFIX_LEN &&
 112             !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
 113                 return -1; /* Refname ends with ".lock". */
 114         return cp - refname;
 115 }
 116
 117 int check_refname_format(const char *refname, int flags)
 118 {
 119         int component_len, component_count = 0;
 120
 121         if (!strcmp(refname, "@"))
 122                 /* Refname is a single character '@'. */
 123                 return -1;
 124
 125         while (1) {
 126                 /* We are at the start of a path component. */
 127                 component_len = check_refname_component(refname, &flags);
 128                 if (component_len <= 0)
 129                         return -1;
 130
 131                 component_count++;
 132                 if (refname[component_len] == '\0')
 133                         break;
 134                 /* Skip to next component. */
 135                 refname += component_len + 1;
 136         }
 137
 138         if (refname[component_len - 1] == '.')
 139                 return -1; /* Refname ends with '.'. */
 140         if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
 141                 return -1; /* Refname has only one component. */
 142         return 0;
 143 }
 144
 145 int refname_is_safe(const char *refname)
 146 {
 147         const char *rest;
 148
 149         if (skip_prefix(refname, "refs/", &rest)) {
 150                 char *buf;
 151                 int result;
 152                 size_t restlen = strlen(rest);
 153
 154                 /* rest must not be empty, or start or end with "/" */
 155                 if (!restlen || *rest == '/' || rest[restlen - 1] == '/')
 156                         return 0;
 157
 158                 /*
 159                  * Does the refname try to escape refs/?
 160                  * For example: refs/foo/../bar is safe but refs/foo/../../bar
 161                  * is not.
 162                  */
 163                 buf = xmallocz(restlen);
 164                 result = !normalize_path_copy(buf, rest) && !strcmp(buf, rest);
 165                 free(buf);
 166                 return result;
 167         }
 168
 169         do {
 170                 if (!isupper(*refname) && *refname != '_')
 171                         return 0;
 172                 refname++;
 173         } while (*refname);
 174         return 1;
 175 }
 176
 177 /*
 178  * Return true if refname, which has the specified oid and flags, can
 179  * be resolved to an object in the database. If the referred-to object
 180  * does not exist, emit a warning and return false.
 181  */
 182 int ref_resolves_to_object(const char *refname,
 183                            const struct object_id *oid,
 184                            unsigned int flags)
 185 {
 186         if (flags & REF_ISBROKEN)
 187                 return 0;
 188         if (!has_sha1_file(oid->hash)) {
 189                 error("%s does not point to a valid object!", refname);
 190                 return 0;
 191         }
 192         return 1;
 193 }
 194
 195 char *refs_resolve_refdup(struct ref_store *refs,
 196                           const char *refname, int resolve_flags,
 197                           unsigned char *sha1, int *flags)
 198 {
 199         const char *result;
 200
 201         result = refs_resolve_ref_unsafe(refs, refname, resolve_flags,
 202                                          sha1, flags);
 203         return xstrdup_or_null(result);
 204 }
 205
 206 char *resolve_refdup(const char *refname, int resolve_flags,
 207                      unsigned char *sha1, int *flags)
 208 {
 209         return refs_resolve_refdup(get_main_ref_store(),
 210                                    refname, resolve_flags,
 211                                    sha1, flags);
 212 }
 213
 214 /* The argument to filter_refs */
 215 struct ref_filter {
 216         const char *pattern;
 217         each_ref_fn *fn;
 218         void *cb_data;
 219 };
 220
 221 int refs_read_ref_full(struct ref_store *refs, const char *refname,
 222                        int resolve_flags, unsigned char *sha1, int *flags)
 223 {
 224         if (refs_resolve_ref_unsafe(refs, refname, resolve_flags, sha1, flags))
 225                 return 0;
 226         return -1;
 227 }
 228
 229 int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
 230 {
 231         return refs_read_ref_full(get_main_ref_store(), refname,
 232                                   resolve_flags, sha1, flags);
 233 }
 234
 235 int read_ref(const char *refname, unsigned char *sha1)
 236 {
 237         return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
 238 }
 239
 240 int ref_exists(const char *refname)
 241 {
 242         unsigned char sha1[20];
 243         return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
 244 }
 245
 246 static int filter_refs(const char *refname, const struct object_id *oid,
 247                            int flags, void *data)
 248 {
 249         struct ref_filter *filter = (struct ref_filter *)data;
 250
 251         if (wildmatch(filter->pattern, refname, 0))
 252                 return 0;
 253         return filter->fn(refname, oid, flags, filter->cb_data);
 254 }
 255
 256 enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
 257 {
 258         struct object *o = lookup_unknown_object(name);
 259
 260         if (o->type == OBJ_NONE) {
 261                 int type = sha1_object_info(name, NULL);
 262                 if (type < 0 || !object_as_type(o, type, 0))
 263                         return PEEL_INVALID;
 264         }
 265
 266         if (o->type != OBJ_TAG)
 267                 return PEEL_NON_TAG;
 268
 269         o = deref_tag_noverify(o);
 270         if (!o)
 271                 return PEEL_INVALID;
 272
 273         hashcpy(sha1, o->oid.hash);
 274         return PEEL_PEELED;
 275 }
 276
 277 struct warn_if_dangling_data {
 278         FILE *fp;
 279         const char *refname;
 280         const struct string_list *refnames;
 281         const char *msg_fmt;
 282 };
 283
 284 static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
 285                                    int flags, void *cb_data)
 286 {
 287         struct warn_if_dangling_data *d = cb_data;
 288         const char *resolves_to;
 289         struct object_id junk;
 290
 291         if (!(flags & REF_ISSYMREF))
 292                 return 0;
 293
 294         resolves_to = resolve_ref_unsafe(refname, 0, junk.hash, NULL);
 295         if (!resolves_to
 296             || (d->refname
 297                 ? strcmp(resolves_to, d->refname)
 298                 : !string_list_has_string(d->refnames, resolves_to))) {
 299                 return 0;
 300         }
 301
 302         fprintf(d->fp, d->msg_fmt, refname);
 303         fputc('\n', d->fp);
 304         return 0;
 305 }
 306
 307 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 308 {
 309         struct warn_if_dangling_data data;
 310
 311         data.fp = fp;
 312         data.refname = refname;
 313         data.refnames = NULL;
 314         data.msg_fmt = msg_fmt;
 315         for_each_rawref(warn_if_dangling_symref, &data);
 316 }
 317
 318 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
 319 {
 320         struct warn_if_dangling_data data;
 321
 322         data.fp = fp;
 323         data.refname = NULL;
 324         data.refnames = refnames;
 325         data.msg_fmt = msg_fmt;
 326         for_each_rawref(warn_if_dangling_symref, &data);
 327 }
 328
 329 int refs_for_each_tag_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 330 {
 331         return refs_for_each_ref_in(refs, "refs/tags/", fn, cb_data);
 332 }
 333
 334 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 335 {
 336         return refs_for_each_tag_ref(get_main_ref_store(), fn, cb_data);
 337 }
 338
 339 int refs_for_each_branch_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 340 {
 341         return refs_for_each_ref_in(refs, "refs/heads/", fn, cb_data);
 342 }
 343
 344 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 345 {
 346         return refs_for_each_branch_ref(get_main_ref_store(), fn, cb_data);
 347 }
 348
 349 int refs_for_each_remote_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 350 {
 351         return refs_for_each_ref_in(refs, "refs/remotes/", fn, cb_data);
 352 }
 353
 354 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 355 {
 356         return refs_for_each_remote_ref(get_main_ref_store(), fn, cb_data);
 357 }
 358
 359 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
 360 {
 361         struct strbuf buf = STRBUF_INIT;
 362         int ret = 0;
 363         struct object_id oid;
 364         int flag;
 365
 366         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
 367         if (!read_ref_full(buf.buf, RESOLVE_REF_READING, oid.hash, &flag))
 368                 ret = fn(buf.buf, &oid, flag, cb_data);
 369         strbuf_release(&buf);
 370
 371         return ret;
 372 }
 373
 374 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 375         const char *prefix, void *cb_data)
 376 {
 377         struct strbuf real_pattern = STRBUF_INIT;
 378         struct ref_filter filter;
 379         int ret;
 380
 381         if (!prefix && !starts_with(pattern, "refs/"))
 382                 strbuf_addstr(&real_pattern, "refs/");
 383         else if (prefix)
 384                 strbuf_addstr(&real_pattern, prefix);
 385         strbuf_addstr(&real_pattern, pattern);
 386
 387         if (!has_glob_specials(pattern)) {
 388                 /* Append implied '/' '*' if not present. */
 389                 strbuf_complete(&real_pattern, '/');
 390                 /* No need to check for '*', there is none. */
 391                 strbuf_addch(&real_pattern, '*');
 392         }
 393
 394         filter.pattern = real_pattern.buf;
 395         filter.fn = fn;
 396         filter.cb_data = cb_data;
 397         ret = for_each_ref(filter_refs, &filter);
 398
 399         strbuf_release(&real_pattern);
 400         return ret;
 401 }
 402
 403 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
 404 {
 405         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
 406 }
 407
 408 const char *prettify_refname(const char *name)
 409 {
 410         if (skip_prefix(name, "refs/heads/", &name) ||
 411             skip_prefix(name, "refs/tags/", &name) ||
 412             skip_prefix(name, "refs/remotes/", &name))
 413                 ; /* nothing */
 414         return name;
 415 }
 416
 417 static const char *ref_rev_parse_rules[] = {
 418         "%.*s",
 419         "refs/%.*s",
 420         "refs/tags/%.*s",
 421         "refs/heads/%.*s",
 422         "refs/remotes/%.*s",
 423         "refs/remotes/%.*s/HEAD",
 424         NULL
 425 };
 426
 427 int refname_match(const char *abbrev_name, const char *full_name)
 428 {
 429         const char **p;
 430         const int abbrev_name_len = strlen(abbrev_name);
 431
 432         for (p = ref_rev_parse_rules; *p; p++) {
 433                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 434                         return 1;
 435                 }
 436         }
 437
 438         return 0;
 439 }
 440
 441 /*
 442  * *string and *len will only be substituted, and *string returned (for
 443  * later free()ing) if the string passed in is a magic short-hand form
 444  * to name a branch.
 445  */
 446 static char *substitute_branch_name(const char **string, int *len)
 447 {
 448         struct strbuf buf = STRBUF_INIT;
 449         int ret = interpret_branch_name(*string, *len, &buf, 0);
 450
 451         if (ret == *len) {
 452                 size_t size;
 453                 *string = strbuf_detach(&buf, &size);
 454                 *len = size;
 455                 return (char *)*string;
 456         }
 457
 458         return NULL;
 459 }
 460
 461 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 462 {
 463         char *last_branch = substitute_branch_name(&str, &len);
 464         int   refs_found  = expand_ref(str, len, sha1, ref);
 465         free(last_branch);
 466         return refs_found;
 467 }
 468
 469 int expand_ref(const char *str, int len, unsigned char *sha1, char **ref)
 470 {
 471         const char **p, *r;
 472         int refs_found = 0;
 473         struct strbuf fullref = STRBUF_INIT;
 474
 475         *ref = NULL;
 476         for (p = ref_rev_parse_rules; *p; p++) {
 477                 unsigned char sha1_from_ref[20];
 478                 unsigned char *this_result;
 479                 int flag;
 480
 481                 this_result = refs_found ? sha1_from_ref : sha1;
 482                 strbuf_reset(&fullref);
 483                 strbuf_addf(&fullref, *p, len, str);
 484                 r = resolve_ref_unsafe(fullref.buf, RESOLVE_REF_READING,
 485                                        this_result, &flag);
 486                 if (r) {
 487                         if (!refs_found++)
 488                                 *ref = xstrdup(r);
 489                         if (!warn_ambiguous_refs)
 490                                 break;
 491                 } else if ((flag & REF_ISSYMREF) && strcmp(fullref.buf, "HEAD")) {
 492                         warning("ignoring dangling symref %s.", fullref.buf);
 493                 } else if ((flag & REF_ISBROKEN) && strchr(fullref.buf, '/')) {
 494                         warning("ignoring broken ref %s.", fullref.buf);
 495                 }
 496         }
 497         strbuf_release(&fullref);
 498         return refs_found;
 499 }
 500
 501 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 502 {
 503         char *last_branch = substitute_branch_name(&str, &len);
 504         const char **p;
 505         int logs_found = 0;
 506         struct strbuf path = STRBUF_INIT;
 507
 508         *log = NULL;
 509         for (p = ref_rev_parse_rules; *p; p++) {
 510                 unsigned char hash[20];
 511                 const char *ref, *it;
 512
 513                 strbuf_reset(&path);
 514                 strbuf_addf(&path, *p, len, str);
 515                 ref = resolve_ref_unsafe(path.buf, RESOLVE_REF_READING,
 516                                          hash, NULL);
 517                 if (!ref)
 518                         continue;
 519                 if (reflog_exists(path.buf))
 520                         it = path.buf;
 521                 else if (strcmp(ref, path.buf) && reflog_exists(ref))
 522                         it = ref;
 523                 else
 524                         continue;
 525                 if (!logs_found++) {
 526                         *log = xstrdup(it);
 527                         hashcpy(sha1, hash);
 528                 }
 529                 if (!warn_ambiguous_refs)
 530                         break;
 531         }
 532         strbuf_release(&path);
 533         free(last_branch);
 534         return logs_found;
 535 }
 536
 537 static int is_per_worktree_ref(const char *refname)
 538 {
 539         return !strcmp(refname, "HEAD") ||
 540                 starts_with(refname, "refs/bisect/");
 541 }
 542
 543 static int is_pseudoref_syntax(const char *refname)
 544 {
 545         const char *c;
 546
 547         for (c = refname; *c; c++) {
 548                 if (!isupper(*c) && *c != '-' && *c != '_')
 549                         return 0;
 550         }
 551
 552         return 1;
 553 }
 554
 555 enum ref_type ref_type(const char *refname)
 556 {
 557         if (is_per_worktree_ref(refname))
 558                 return REF_TYPE_PER_WORKTREE;
 559         if (is_pseudoref_syntax(refname))
 560                 return REF_TYPE_PSEUDOREF;
 561        return REF_TYPE_NORMAL;
 562 }
 563
 564 long get_files_ref_lock_timeout_ms(void)
 565 {
 566         static int configured = 0;
 567
 568         /* The default timeout is 100 ms: */
 569         static int timeout_ms = 100;
 570
 571         if (!configured) {
 572                 git_config_get_int("core.filesreflocktimeout", &timeout_ms);
 573                 configured = 1;
 574         }
 575
 576         return timeout_ms;
 577 }
 578
 579 static int write_pseudoref(const char *pseudoref, const unsigned char *sha1,
 580                            const unsigned char *old_sha1, struct strbuf *err)
 581 {
 582         const char *filename;
 583         int fd;
 584         static struct lock_file lock;
 585         struct strbuf buf = STRBUF_INIT;
 586         int ret = -1;
 587
 588         strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
 589
 590         filename = git_path("%s", pseudoref);
 591         fd = hold_lock_file_for_update_timeout(&lock, filename,
 592                                                LOCK_DIE_ON_ERROR,
 593                                                get_files_ref_lock_timeout_ms());
 594         if (fd < 0) {
 595                 strbuf_addf(err, "could not open '%s' for writing: %s",
 596                             filename, strerror(errno));
 597                 goto done;
 598         }
 599
 600         if (old_sha1) {
 601                 unsigned char actual_old_sha1[20];
 602
 603                 if (read_ref(pseudoref, actual_old_sha1))
 604                         die("could not read ref '%s'", pseudoref);
 605                 if (hashcmp(actual_old_sha1, old_sha1)) {
 606                         strbuf_addf(err, "unexpected sha1 when writing '%s'", pseudoref);
 607                         rollback_lock_file(&lock);
 608                         goto done;
 609                 }
 610         }
 611
 612         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 613                 strbuf_addf(err, "could not write to '%s'", filename);
 614                 rollback_lock_file(&lock);
 615                 goto done;
 616         }
 617
 618         commit_lock_file(&lock);
 619         ret = 0;
 620 done:
 621         strbuf_release(&buf);
 622         return ret;
 623 }
 624
 625 static int delete_pseudoref(const char *pseudoref, const unsigned char *old_sha1)
 626 {
 627         static struct lock_file lock;
 628         const char *filename;
 629
 630         filename = git_path("%s", pseudoref);
 631
 632         if (old_sha1 && !is_null_sha1(old_sha1)) {
 633                 int fd;
 634                 unsigned char actual_old_sha1[20];
 635
 636                 fd = hold_lock_file_for_update_timeout(
 637                                 &lock, filename, LOCK_DIE_ON_ERROR,
 638                                 get_files_ref_lock_timeout_ms());
 639                 if (fd < 0)
 640                         die_errno(_("Could not open '%s' for writing"), filename);
 641                 if (read_ref(pseudoref, actual_old_sha1))
 642                         die("could not read ref '%s'", pseudoref);
 643                 if (hashcmp(actual_old_sha1, old_sha1)) {
 644                         warning("Unexpected sha1 when deleting %s", pseudoref);
 645                         rollback_lock_file(&lock);
 646                         return -1;
 647                 }
 648
 649                 unlink(filename);
 650                 rollback_lock_file(&lock);
 651         } else {
 652                 unlink(filename);
 653         }
 654
 655         return 0;
 656 }
 657
 658 int refs_delete_ref(struct ref_store *refs, const char *msg,
 659                     const char *refname,
 660                     const unsigned char *old_sha1,
 661                     unsigned int flags)
 662 {
 663         struct ref_transaction *transaction;
 664         struct strbuf err = STRBUF_INIT;
 665
 666         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
 667                 assert(refs == get_main_ref_store());
 668                 return delete_pseudoref(refname, old_sha1);
 669         }
 670
 671         transaction = ref_store_transaction_begin(refs, &err);
 672         if (!transaction ||
 673             ref_transaction_delete(transaction, refname, old_sha1,
 674                                    flags, msg, &err) ||
 675             ref_transaction_commit(transaction, &err)) {
 676                 error("%s", err.buf);
 677                 ref_transaction_free(transaction);
 678                 strbuf_release(&err);
 679                 return 1;
 680         }
 681         ref_transaction_free(transaction);
 682         strbuf_release(&err);
 683         return 0;
 684 }
 685
 686 int delete_ref(const char *msg, const char *refname,
 687                const unsigned char *old_sha1, unsigned int flags)
 688 {
 689         return refs_delete_ref(get_main_ref_store(), msg, refname,
 690                                old_sha1, flags);
 691 }
 692
 693 int copy_reflog_msg(char *buf, const char *msg)
 694 {
 695         char *cp = buf;
 696         char c;
 697         int wasspace = 1;
 698
 699         *cp++ = '\t';
 700         while ((c = *msg++)) {
 701                 if (wasspace && isspace(c))
 702                         continue;
 703                 wasspace = isspace(c);
 704                 if (wasspace)
 705                         c = ' ';
 706                 *cp++ = c;
 707         }
 708         while (buf < cp && isspace(cp[-1]))
 709                 cp--;
 710         *cp++ = '\n';
 711         return cp - buf;
 712 }
 713
 714 int should_autocreate_reflog(const char *refname)
 715 {
 716         switch (log_all_ref_updates) {
 717         case LOG_REFS_ALWAYS:
 718                 return 1;
 719         case LOG_REFS_NORMAL:
 720                 return starts_with(refname, "refs/heads/") ||
 721                         starts_with(refname, "refs/remotes/") ||
 722                         starts_with(refname, "refs/notes/") ||
 723                         !strcmp(refname, "HEAD");
 724         default:
 725                 return 0;
 726         }
 727 }
 728
 729 int is_branch(const char *refname)
 730 {
 731         return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
 732 }
 733
 734 struct read_ref_at_cb {
 735         const char *refname;
 736         timestamp_t at_time;
 737         int cnt;
 738         int reccnt;
 739         unsigned char *sha1;
 740         int found_it;
 741
 742         unsigned char osha1[20];
 743         unsigned char nsha1[20];
 744         int tz;
 745         timestamp_t date;
 746         char **msg;
 747         timestamp_t *cutoff_time;
 748         int *cutoff_tz;
 749         int *cutoff_cnt;
 750 };
 751
 752 static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
 753                 const char *email, timestamp_t timestamp, int tz,
 754                 const char *message, void *cb_data)
 755 {
 756         struct read_ref_at_cb *cb = cb_data;
 757
 758         cb->reccnt++;
 759         cb->tz = tz;
 760         cb->date = timestamp;
 761
 762         if (timestamp <= cb->at_time || cb->cnt == 0) {
 763                 if (cb->msg)
 764                         *cb->msg = xstrdup(message);
 765                 if (cb->cutoff_time)
 766                         *cb->cutoff_time = timestamp;
 767                 if (cb->cutoff_tz)
 768                         *cb->cutoff_tz = tz;
 769                 if (cb->cutoff_cnt)
 770                         *cb->cutoff_cnt = cb->reccnt - 1;
 771                 /*
 772                  * we have not yet updated cb->[n|o]sha1 so they still
 773                  * hold the values for the previous record.
 774                  */
 775                 if (!is_null_sha1(cb->osha1)) {
 776                         hashcpy(cb->sha1, noid->hash);
 777                         if (hashcmp(cb->osha1, noid->hash))
 778                                 warning("Log for ref %s has gap after %s.",
 779                                         cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
 780                 }
 781                 else if (cb->date == cb->at_time)
 782                         hashcpy(cb->sha1, noid->hash);
 783                 else if (hashcmp(noid->hash, cb->sha1))
 784                         warning("Log for ref %s unexpectedly ended on %s.",
 785                                 cb->refname, show_date(cb->date, cb->tz,
 786                                                        DATE_MODE(RFC2822)));
 787                 hashcpy(cb->osha1, ooid->hash);
 788                 hashcpy(cb->nsha1, noid->hash);
 789                 cb->found_it = 1;
 790                 return 1;
 791         }
 792         hashcpy(cb->osha1, ooid->hash);
 793         hashcpy(cb->nsha1, noid->hash);
 794         if (cb->cnt > 0)
 795                 cb->cnt--;
 796         return 0;
 797 }
 798
 799 static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
 800                                   const char *email, timestamp_t timestamp,
 801                                   int tz, const char *message, void *cb_data)
 802 {
 803         struct read_ref_at_cb *cb = cb_data;
 804
 805         if (cb->msg)
 806                 *cb->msg = xstrdup(message);
 807         if (cb->cutoff_time)
 808                 *cb->cutoff_time = timestamp;
 809         if (cb->cutoff_tz)
 810                 *cb->cutoff_tz = tz;
 811         if (cb->cutoff_cnt)
 812                 *cb->cutoff_cnt = cb->reccnt;
 813         hashcpy(cb->sha1, ooid->hash);
 814         if (is_null_sha1(cb->sha1))
 815                 hashcpy(cb->sha1, noid->hash);
 816         /* We just want the first entry */
 817         return 1;
 818 }
 819
 820 int read_ref_at(const char *refname, unsigned int flags, timestamp_t at_time, int cnt,
 821                 unsigned char *sha1, char **msg,
 822                 timestamp_t *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
 823 {
 824         struct read_ref_at_cb cb;
 825
 826         memset(&cb, 0, sizeof(cb));
 827         cb.refname = refname;
 828         cb.at_time = at_time;
 829         cb.cnt = cnt;
 830         cb.msg = msg;
 831         cb.cutoff_time = cutoff_time;
 832         cb.cutoff_tz = cutoff_tz;
 833         cb.cutoff_cnt = cutoff_cnt;
 834         cb.sha1 = sha1;
 835
 836         for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
 837
 838         if (!cb.reccnt) {
 839                 if (flags & GET_OID_QUIETLY)
 840                         exit(128);
 841                 else
 842                         die("Log for %s is empty.", refname);
 843         }
 844         if (cb.found_it)
 845                 return 0;
 846
 847         for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
 848
 849         return 1;
 850 }
 851
 852 struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
 853                                                     struct strbuf *err)
 854 {
 855         struct ref_transaction *tr;
 856         assert(err);
 857
 858         tr = xcalloc(1, sizeof(struct ref_transaction));
 859         tr->ref_store = refs;
 860         return tr;
 861 }
 862
 863 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 864 {
 865         return ref_store_transaction_begin(get_main_ref_store(), err);
 866 }
 867
 868 void ref_transaction_free(struct ref_transaction *transaction)
 869 {
 870         size_t i;
 871
 872         if (!transaction)
 873                 return;
 874
 875         switch (transaction->state) {
 876         case REF_TRANSACTION_OPEN:
 877         case REF_TRANSACTION_CLOSED:
 878                 /* OK */
 879                 break;
 880         case REF_TRANSACTION_PREPARED:
 881                 die("BUG: free called on a prepared reference transaction");
 882                 break;
 883         default:
 884                 die("BUG: unexpected reference transaction state");
 885                 break;
 886         }
 887
 888         for (i = 0; i < transaction->nr; i++) {
 889                 free(transaction->updates[i]->msg);
 890                 free(transaction->updates[i]);
 891         }
 892         free(transaction->updates);
 893         free(transaction);
 894 }
 895
 896 struct ref_update *ref_transaction_add_update(
 897                 struct ref_transaction *transaction,
 898                 const char *refname, unsigned int flags,
 899                 const unsigned char *new_sha1,
 900                 const unsigned char *old_sha1,
 901                 const char *msg)
 902 {
 903         struct ref_update *update;
 904
 905         if (transaction->state != REF_TRANSACTION_OPEN)
 906                 die("BUG: update called for transaction that is not open");
 907
 908         if ((flags & REF_ISPRUNING) && !(flags & REF_NODEREF))
 909                 die("BUG: REF_ISPRUNING set without REF_NODEREF");
 910
 911         FLEX_ALLOC_STR(update, refname, refname);
 912         ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
 913         transaction->updates[transaction->nr++] = update;
 914
 915         update->flags = flags;
 916
 917         if (flags & REF_HAVE_NEW)
 918                 hashcpy(update->new_oid.hash, new_sha1);
 919         if (flags & REF_HAVE_OLD)
 920                 hashcpy(update->old_oid.hash, old_sha1);
 921         update->msg = xstrdup_or_null(msg);
 922         return update;
 923 }
 924
 925 int ref_transaction_update(struct ref_transaction *transaction,
 926                            const char *refname,
 927                            const unsigned char *new_sha1,
 928                            const unsigned char *old_sha1,
 929                            unsigned int flags, const char *msg,
 930                            struct strbuf *err)
 931 {
 932         assert(err);
 933
 934         if ((new_sha1 && !is_null_sha1(new_sha1)) ?
 935             check_refname_format(refname, REFNAME_ALLOW_ONELEVEL) :
 936             !refname_is_safe(refname)) {
 937                 strbuf_addf(err, "refusing to update ref with bad name '%s'",
 938                             refname);
 939                 return -1;
 940         }
 941
 942         flags &= REF_TRANSACTION_UPDATE_ALLOWED_FLAGS;
 943
 944         flags |= (new_sha1 ? REF_HAVE_NEW : 0) | (old_sha1 ? REF_HAVE_OLD : 0);
 945
 946         ref_transaction_add_update(transaction, refname, flags,
 947                                    new_sha1, old_sha1, msg);
 948         return 0;
 949 }
 950
 951 int ref_transaction_create(struct ref_transaction *transaction,
 952                            const char *refname,
 953                            const unsigned char *new_sha1,
 954                            unsigned int flags, const char *msg,
 955                            struct strbuf *err)
 956 {
 957         if (!new_sha1 || is_null_sha1(new_sha1))
 958                 die("BUG: create called without valid new_sha1");
 959         return ref_transaction_update(transaction, refname, new_sha1,
 960                                       null_sha1, flags, msg, err);
 961 }
 962
 963 int ref_transaction_delete(struct ref_transaction *transaction,
 964                            const char *refname,
 965                            const unsigned char *old_sha1,
 966                            unsigned int flags, const char *msg,
 967                            struct strbuf *err)
 968 {
 969         if (old_sha1 && is_null_sha1(old_sha1))
 970                 die("BUG: delete called with old_sha1 set to zeros");
 971         return ref_transaction_update(transaction, refname,
 972                                       null_sha1, old_sha1,
 973                                       flags, msg, err);
 974 }
 975
 976 int ref_transaction_verify(struct ref_transaction *transaction,
 977                            const char *refname,
 978                            const unsigned char *old_sha1,
 979                            unsigned int flags,
 980                            struct strbuf *err)
 981 {
 982         if (!old_sha1)
 983                 die("BUG: verify called with old_sha1 set to NULL");
 984         return ref_transaction_update(transaction, refname,
 985                                       NULL, old_sha1,
 986                                       flags, NULL, err);
 987 }
 988
 989 int update_ref_oid(const char *msg, const char *refname,
 990                const struct object_id *new_oid, const struct object_id *old_oid,
 991                unsigned int flags, enum action_on_err onerr)
 992 {
 993         return update_ref(msg, refname, new_oid ? new_oid->hash : NULL,
 994                 old_oid ? old_oid->hash : NULL, flags, onerr);
 995 }
 996
 997 int refs_update_ref(struct ref_store *refs, const char *msg,
 998                     const char *refname, const unsigned char *new_sha1,
 999                     const unsigned char *old_sha1, unsigned int flags,
1000                     enum action_on_err onerr)
1001 {
1002         struct ref_transaction *t = NULL;
1003         struct strbuf err = STRBUF_INIT;
1004         int ret = 0;
1005
1006         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
1007                 assert(refs == get_main_ref_store());
1008                 ret = write_pseudoref(refname, new_sha1, old_sha1, &err);
1009         } else {
1010                 t = ref_store_transaction_begin(refs, &err);
1011                 if (!t ||
1012                     ref_transaction_update(t, refname, new_sha1, old_sha1,
1013                                            flags, msg, &err) ||
1014                     ref_transaction_commit(t, &err)) {
1015                         ret = 1;
1016                         ref_transaction_free(t);
1017                 }
1018         }
1019         if (ret) {
1020                 const char *str = "update_ref failed for ref '%s': %s";
1021
1022                 switch (onerr) {
1023                 case UPDATE_REFS_MSG_ON_ERR:
1024                         error(str, refname, err.buf);
1025                         break;
1026                 case UPDATE_REFS_DIE_ON_ERR:
1027                         die(str, refname, err.buf);
1028                         break;
1029                 case UPDATE_REFS_QUIET_ON_ERR:
1030                         break;
1031                 }
1032                 strbuf_release(&err);
1033                 return 1;
1034         }
1035         strbuf_release(&err);
1036         if (t)
1037                 ref_transaction_free(t);
1038         return 0;
1039 }
1040
1041 int update_ref(const char *msg, const char *refname,
1042                const unsigned char *new_sha1,
1043                const unsigned char *old_sha1,
1044                unsigned int flags, enum action_on_err onerr)
1045 {
1046         return refs_update_ref(get_main_ref_store(), msg, refname, new_sha1,
1047                                old_sha1, flags, onerr);
1048 }
1049
1050 char *shorten_unambiguous_ref(const char *refname, int strict)
1051 {
1052         int i;
1053         static char **scanf_fmts;
1054         static int nr_rules;
1055         char *short_name;
1056         struct strbuf resolved_buf = STRBUF_INIT;
1057
1058         if (!nr_rules) {
1059                 /*
1060                  * Pre-generate scanf formats from ref_rev_parse_rules[].
1061                  * Generate a format suitable for scanf from a
1062                  * ref_rev_parse_rules rule by interpolating "%s" at the
1063                  * location of the "%.*s".
1064                  */
1065                 size_t total_len = 0;
1066                 size_t offset = 0;
1067
1068                 /* the rule list is NULL terminated, count them first */
1069                 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
1070                         /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
1071                         total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
1072
1073                 scanf_fmts = xmalloc(st_add(st_mult(sizeof(char *), nr_rules), total_len));
1074
1075                 offset = 0;
1076                 for (i = 0; i < nr_rules; i++) {
1077                         assert(offset < total_len);
1078                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
1079                         offset += snprintf(scanf_fmts[i], total_len - offset,
1080                                            ref_rev_parse_rules[i], 2, "%s") + 1;
1081                 }
1082         }
1083
1084         /* bail out if there are no rules */
1085         if (!nr_rules)
1086                 return xstrdup(refname);
1087
1088         /* buffer for scanf result, at most refname must fit */
1089         short_name = xstrdup(refname);
1090
1091         /* skip first rule, it will always match */
1092         for (i = nr_rules - 1; i > 0 ; --i) {
1093                 int j;
1094                 int rules_to_fail = i;
1095                 int short_name_len;
1096
1097                 if (1 != sscanf(refname, scanf_fmts[i], short_name))
1098                         continue;
1099
1100                 short_name_len = strlen(short_name);
1101
1102                 /*
1103                  * in strict mode, all (except the matched one) rules
1104                  * must fail to resolve to a valid non-ambiguous ref
1105                  */
1106                 if (strict)
1107                         rules_to_fail = nr_rules;
1108
1109                 /*
1110                  * check if the short name resolves to a valid ref,
1111                  * but use only rules prior to the matched one
1112                  */
1113                 for (j = 0; j < rules_to_fail; j++) {
1114                         const char *rule = ref_rev_parse_rules[j];
1115
1116                         /* skip matched rule */
1117                         if (i == j)
1118                                 continue;
1119
1120                         /*
1121                          * the short name is ambiguous, if it resolves
1122                          * (with this previous rule) to a valid ref
1123                          * read_ref() returns 0 on success
1124                          */
1125                         strbuf_reset(&resolved_buf);
1126                         strbuf_addf(&resolved_buf, rule,
1127                                     short_name_len, short_name);
1128                         if (ref_exists(resolved_buf.buf))
1129                                 break;
1130                 }
1131
1132                 /*
1133                  * short name is non-ambiguous if all previous rules
1134                  * haven't resolved to a valid ref
1135                  */
1136                 if (j == rules_to_fail) {
1137                         strbuf_release(&resolved_buf);
1138                         return short_name;
1139                 }
1140         }
1141
1142         strbuf_release(&resolved_buf);
1143         free(short_name);
1144         return xstrdup(refname);
1145 }
1146
1147 static struct string_list *hide_refs;
1148
1149 int parse_hide_refs_config(const char *var, const char *value, const char *section)
1150 {
1151         const char *key;
1152         if (!strcmp("transfer.hiderefs", var) ||
1153             (!parse_config_key(var, section, NULL, NULL, &key) &&
1154              !strcmp(key, "hiderefs"))) {
1155                 char *ref;
1156                 int len;
1157
1158                 if (!value)
1159                         return config_error_nonbool(var);
1160                 ref = xstrdup(value);
1161                 len = strlen(ref);
1162                 while (len && ref[len - 1] == '/')
1163                         ref[--len] = '\0';
1164                 if (!hide_refs) {
1165                         hide_refs = xcalloc(1, sizeof(*hide_refs));
1166                         hide_refs->strdup_strings = 1;
1167                 }
1168                 string_list_append(hide_refs, ref);
1169         }
1170         return 0;
1171 }
1172
1173 int ref_is_hidden(const char *refname, const char *refname_full)
1174 {
1175         int i;
1176
1177         if (!hide_refs)
1178                 return 0;
1179         for (i = hide_refs->nr - 1; i >= 0; i--) {
1180                 const char *match = hide_refs->items[i].string;
1181                 const char *subject;
1182                 int neg = 0;
1183                 const char *p;
1184
1185                 if (*match == '!') {
1186                         neg = 1;
1187                         match++;
1188                 }
1189
1190                 if (*match == '^') {
1191                         subject = refname_full;
1192                         match++;
1193                 } else {
1194                         subject = refname;
1195                 }
1196
1197                 /* refname can be NULL when namespaces are used. */
1198                 if (subject &&
1199                     skip_prefix(subject, match, &p) &&
1200                     (!*p || *p == '/'))
1201                         return !neg;
1202         }
1203         return 0;
1204 }
1205
1206 const char *find_descendant_ref(const char *dirname,
1207                                 const struct string_list *extras,
1208                                 const struct string_list *skip)
1209 {
1210         int pos;
1211
1212         if (!extras)
1213                 return NULL;
1214
1215         /*
1216          * Look at the place where dirname would be inserted into
1217          * extras. If there is an entry at that position that starts
1218          * with dirname (remember, dirname includes the trailing
1219          * slash) and is not in skip, then we have a conflict.
1220          */
1221         for (pos = string_list_find_insert_index(extras, dirname, 0);
1222              pos < extras->nr; pos++) {
1223                 const char *extra_refname = extras->items[pos].string;
1224
1225                 if (!starts_with(extra_refname, dirname))
1226                         break;
1227
1228                 if (!skip || !string_list_has_string(skip, extra_refname))
1229                         return extra_refname;
1230         }
1231         return NULL;
1232 }
1233
1234 int refs_rename_ref_available(struct ref_store *refs,
1235                               const char *old_refname,
1236                               const char *new_refname)
1237 {
1238         struct string_list skip = STRING_LIST_INIT_NODUP;
1239         struct strbuf err = STRBUF_INIT;
1240         int ok;
1241
1242         string_list_insert(&skip, old_refname);
1243         ok = !refs_verify_refname_available(refs, new_refname,
1244                                             NULL, &skip, &err);
1245         if (!ok)
1246                 error("%s", err.buf);
1247
1248         string_list_clear(&skip, 0);
1249         strbuf_release(&err);
1250         return ok;
1251 }
1252
1253 int refs_head_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1254 {
1255         struct object_id oid;
1256         int flag;
1257
1258         if (!refs_read_ref_full(refs, "HEAD", RESOLVE_REF_READING,
1259                                 oid.hash, &flag))
1260                 return fn("HEAD", &oid, flag, cb_data);
1261
1262         return 0;
1263 }
1264
1265 int head_ref(each_ref_fn fn, void *cb_data)
1266 {
1267         return refs_head_ref(get_main_ref_store(), fn, cb_data);
1268 }
1269
1270 struct ref_iterator *refs_ref_iterator_begin(
1271                 struct ref_store *refs,
1272                 const char *prefix, int trim, int flags)
1273 {
1274         struct ref_iterator *iter;
1275
1276         if (ref_paranoia < 0)
1277                 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1278         if (ref_paranoia)
1279                 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1280
1281         iter = refs->be->iterator_begin(refs, prefix, flags);
1282
1283         /*
1284          * `iterator_begin()` already takes care of prefix, but we
1285          * might need to do some trimming:
1286          */
1287         if (trim)
1288                 iter = prefix_ref_iterator_begin(iter, "", trim);
1289
1290         return iter;
1291 }
1292
1293 /*
1294  * Call fn for each reference in the specified submodule for which the
1295  * refname begins with prefix. If trim is non-zero, then trim that
1296  * many characters off the beginning of each refname before passing
1297  * the refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to
1298  * include broken references in the iteration. If fn ever returns a
1299  * non-zero value, stop the iteration and return that value;
1300  * otherwise, return 0.
1301  */
1302 static int do_for_each_ref(struct ref_store *refs, const char *prefix,
1303                            each_ref_fn fn, int trim, int flags, void *cb_data)
1304 {
1305         struct ref_iterator *iter;
1306
1307         if (!refs)
1308                 return 0;
1309
1310         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1311
1312         return do_for_each_ref_iterator(iter, fn, cb_data);
1313 }
1314
1315 int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1316 {
1317         return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
1318 }
1319
1320 int for_each_ref(each_ref_fn fn, void *cb_data)
1321 {
1322         return refs_for_each_ref(get_main_ref_store(), fn, cb_data);
1323 }
1324
1325 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
1326                          each_ref_fn fn, void *cb_data)
1327 {
1328         return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
1329 }
1330
1331 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1332 {
1333         return refs_for_each_ref_in(get_main_ref_store(), prefix, fn, cb_data);
1334 }
1335
1336 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1337 {
1338         unsigned int flag = 0;
1339
1340         if (broken)
1341                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1342         return do_for_each_ref(get_main_ref_store(),
1343                                prefix, fn, 0, flag, cb_data);
1344 }
1345
1346 int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
1347                              each_ref_fn fn, void *cb_data,
1348                              unsigned int broken)
1349 {
1350         unsigned int flag = 0;
1351
1352         if (broken)
1353                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1354         return do_for_each_ref(refs, prefix, fn, 0, flag, cb_data);
1355 }
1356
1357 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1358 {
1359         return do_for_each_ref(get_main_ref_store(),
1360                                git_replace_ref_base, fn,
1361                                strlen(git_replace_ref_base),
1362                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1363 }
1364
1365 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1366 {
1367         struct strbuf buf = STRBUF_INIT;
1368         int ret;
1369         strbuf_addf(&buf, "%srefs/", get_git_namespace());
1370         ret = do_for_each_ref(get_main_ref_store(),
1371                               buf.buf, fn, 0, 0, cb_data);
1372         strbuf_release(&buf);
1373         return ret;
1374 }
1375
1376 int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1377 {
1378         return do_for_each_ref(refs, "", fn, 0,
1379                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1380 }
1381
1382 int for_each_rawref(each_ref_fn fn, void *cb_data)
1383 {
1384         return refs_for_each_rawref(get_main_ref_store(), fn, cb_data);
1385 }
1386
1387 int refs_read_raw_ref(struct ref_store *ref_store,
1388                       const char *refname, unsigned char *sha1,
1389                       struct strbuf *referent, unsigned int *type)
1390 {
1391         return ref_store->be->read_raw_ref(ref_store, refname, sha1, referent, type);
1392 }
1393
1394 /* This function needs to return a meaningful errno on failure */
1395 const char *refs_resolve_ref_unsafe(struct ref_store *refs,
1396                                     const char *refname,
1397                                     int resolve_flags,
1398                                     unsigned char *sha1, int *flags)
1399 {
1400         static struct strbuf sb_refname = STRBUF_INIT;
1401         int unused_flags;
1402         int symref_count;
1403
1404         if (!flags)
1405                 flags = &unused_flags;
1406
1407         *flags = 0;
1408
1409         if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1410                 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1411                     !refname_is_safe(refname)) {
1412                         errno = EINVAL;
1413                         return NULL;
1414                 }
1415
1416                 /*
1417                  * dwim_ref() uses REF_ISBROKEN to distinguish between
1418                  * missing refs and refs that were present but invalid,
1419                  * to complain about the latter to stderr.
1420                  *
1421                  * We don't know whether the ref exists, so don't set
1422                  * REF_ISBROKEN yet.
1423                  */
1424                 *flags |= REF_BAD_NAME;
1425         }
1426
1427         for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
1428                 unsigned int read_flags = 0;
1429
1430                 if (refs_read_raw_ref(refs, refname,
1431                                       sha1, &sb_refname, &read_flags)) {
1432                         *flags |= read_flags;
1433                         if (errno != ENOENT || (resolve_flags & RESOLVE_REF_READING))
1434                                 return NULL;
1435                         hashclr(sha1);
1436                         if (*flags & REF_BAD_NAME)
1437                                 *flags |= REF_ISBROKEN;
1438                         return refname;
1439                 }
1440
1441                 *flags |= read_flags;
1442
1443                 if (!(read_flags & REF_ISSYMREF)) {
1444                         if (*flags & REF_BAD_NAME) {
1445                                 hashclr(sha1);
1446                                 *flags |= REF_ISBROKEN;
1447                         }
1448                         return refname;
1449                 }
1450
1451                 refname = sb_refname.buf;
1452                 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1453                         hashclr(sha1);
1454                         return refname;
1455                 }
1456                 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1457                         if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1458                             !refname_is_safe(refname)) {
1459                                 errno = EINVAL;
1460                                 return NULL;
1461                         }
1462
1463                         *flags |= REF_ISBROKEN | REF_BAD_NAME;
1464                 }
1465         }
1466
1467         errno = ELOOP;
1468         return NULL;
1469 }
1470
1471 /* backend functions */
1472 int refs_init_db(struct strbuf *err)
1473 {
1474         struct ref_store *refs = get_main_ref_store();
1475
1476         return refs->be->init_db(refs, err);
1477 }
1478
1479 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1480                                unsigned char *sha1, int *flags)
1481 {
1482         return refs_resolve_ref_unsafe(get_main_ref_store(), refname,
1483                                        resolve_flags, sha1, flags);
1484 }
1485
1486 int resolve_gitlink_ref(const char *submodule, const char *refname,
1487                         unsigned char *sha1)
1488 {
1489         struct ref_store *refs;
1490         int flags;
1491
1492         refs = get_submodule_ref_store(submodule);
1493
1494         if (!refs)
1495                 return -1;
1496
1497         if (!refs_resolve_ref_unsafe(refs, refname, 0, sha1, &flags) ||
1498             is_null_sha1(sha1))
1499                 return -1;
1500         return 0;
1501 }
1502
1503 struct ref_store_hash_entry
1504 {
1505         struct hashmap_entry ent; /* must be the first member! */
1506
1507         struct ref_store *refs;
1508
1509         /* NUL-terminated identifier of the ref store: */
1510         char name[FLEX_ARRAY];
1511 };
1512
1513 static int ref_store_hash_cmp(const void *unused_cmp_data,
1514                               const void *entry, const void *entry_or_key,
1515                               const void *keydata)
1516 {
1517         const struct ref_store_hash_entry *e1 = entry, *e2 = entry_or_key;
1518         const char *name = keydata ? keydata : e2->name;
1519
1520         return strcmp(e1->name, name);
1521 }
1522
1523 static struct ref_store_hash_entry *alloc_ref_store_hash_entry(
1524                 const char *name, struct ref_store *refs)
1525 {
1526         struct ref_store_hash_entry *entry;
1527
1528         FLEX_ALLOC_STR(entry, name, name);
1529         hashmap_entry_init(entry, strhash(name));
1530         entry->refs = refs;
1531         return entry;
1532 }
1533
1534 /* A pointer to the ref_store for the main repository: */
1535 static struct ref_store *main_ref_store;
1536
1537 /* A hashmap of ref_stores, stored by submodule name: */
1538 static struct hashmap submodule_ref_stores;
1539
1540 /* A hashmap of ref_stores, stored by worktree id: */
1541 static struct hashmap worktree_ref_stores;
1542
1543 /*
1544  * Look up a ref store by name. If that ref_store hasn't been
1545  * registered yet, return NULL.
1546  */
1547 static struct ref_store *lookup_ref_store_map(struct hashmap *map,
1548                                               const char *name)
1549 {
1550         struct ref_store_hash_entry *entry;
1551
1552         if (!map->tablesize)
1553                 /* It's initialized on demand in register_ref_store(). */
1554                 return NULL;
1555
1556         entry = hashmap_get_from_hash(map, strhash(name), name);
1557         return entry ? entry->refs : NULL;
1558 }
1559
1560 /*
1561  * Create, record, and return a ref_store instance for the specified
1562  * gitdir.
1563  */
1564 static struct ref_store *ref_store_init(const char *gitdir,
1565                                         unsigned int flags)
1566 {
1567         const char *be_name = "files";
1568         struct ref_storage_be *be = find_ref_storage_backend(be_name);
1569         struct ref_store *refs;
1570
1571         if (!be)
1572                 die("BUG: reference backend %s is unknown", be_name);
1573
1574         refs = be->init(gitdir, flags);
1575         return refs;
1576 }
1577
1578 struct ref_store *get_main_ref_store(void)
1579 {
1580         if (main_ref_store)
1581                 return main_ref_store;
1582
1583         main_ref_store = ref_store_init(get_git_dir(), REF_STORE_ALL_CAPS);
1584         return main_ref_store;
1585 }
1586
1587 /*
1588  * Associate a ref store with a name. It is a fatal error to call this
1589  * function twice for the same name.
1590  */
1591 static void register_ref_store_map(struct hashmap *map,
1592                                    const char *type,
1593                                    struct ref_store *refs,
1594                                    const char *name)
1595 {
1596         if (!map->tablesize)
1597                 hashmap_init(map, ref_store_hash_cmp, NULL, 0);
1598
1599         if (hashmap_put(map, alloc_ref_store_hash_entry(name, refs)))
1600                 die("BUG: %s ref_store '%s' initialized twice", type, name);
1601 }
1602
1603 struct ref_store *get_submodule_ref_store(const char *submodule)
1604 {
1605         struct strbuf submodule_sb = STRBUF_INIT;
1606         struct ref_store *refs;
1607         char *to_free = NULL;
1608         size_t len;
1609
1610         if (!submodule)
1611                 return NULL;
1612
1613         len = strlen(submodule);
1614         while (len && is_dir_sep(submodule[len - 1]))
1615                 len--;
1616         if (!len)
1617                 return NULL;
1618
1619         if (submodule[len])
1620                 /* We need to strip off one or more trailing slashes */
1621                 submodule = to_free = xmemdupz(submodule, len);
1622
1623         refs = lookup_ref_store_map(&submodule_ref_stores, submodule);
1624         if (refs)
1625                 goto done;
1626
1627         strbuf_addstr(&submodule_sb, submodule);
1628         if (!is_nonbare_repository_dir(&submodule_sb))
1629                 goto done;
1630
1631         if (submodule_to_gitdir(&submodule_sb, submodule))
1632                 goto done;
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 done:
1641         strbuf_release(&submodule_sb);
1642         free(to_free);
1643
1644         return refs;
1645 }
1646
1647 struct ref_store *get_worktree_ref_store(const struct worktree *wt)
1648 {
1649         struct ref_store *refs;
1650         const char *id;
1651
1652         if (wt->is_current)
1653                 return get_main_ref_store();
1654
1655         id = wt->id ? wt->id : "/";
1656         refs = lookup_ref_store_map(&worktree_ref_stores, id);
1657         if (refs)
1658                 return refs;
1659
1660         if (wt->id)
1661                 refs = ref_store_init(git_common_path("worktrees/%s", wt->id),
1662                                       REF_STORE_ALL_CAPS);
1663         else
1664                 refs = ref_store_init(get_git_common_dir(),
1665                                       REF_STORE_ALL_CAPS);
1666
1667         if (refs)
1668                 register_ref_store_map(&worktree_ref_stores, "worktree",
1669                                        refs, id);
1670         return refs;
1671 }
1672
1673 void base_ref_store_init(struct ref_store *refs,
1674                          const struct ref_storage_be *be)
1675 {
1676         refs->be = be;
1677 }
1678
1679 /* backend functions */
1680 int refs_pack_refs(struct ref_store *refs, unsigned int flags)
1681 {
1682         return refs->be->pack_refs(refs, flags);
1683 }
1684
1685 int refs_peel_ref(struct ref_store *refs, const char *refname,
1686                   unsigned char *sha1)
1687 {
1688         return refs->be->peel_ref(refs, refname, sha1);
1689 }
1690
1691 int peel_ref(const char *refname, unsigned char *sha1)
1692 {
1693         return refs_peel_ref(get_main_ref_store(), refname, sha1);
1694 }
1695
1696 int refs_create_symref(struct ref_store *refs,
1697                        const char *ref_target,
1698                        const char *refs_heads_master,
1699                        const char *logmsg)
1700 {
1701         return refs->be->create_symref(refs, ref_target,
1702                                        refs_heads_master,
1703                                        logmsg);
1704 }
1705
1706 int create_symref(const char *ref_target, const char *refs_heads_master,
1707                   const char *logmsg)
1708 {
1709         return refs_create_symref(get_main_ref_store(), ref_target,
1710                                   refs_heads_master, logmsg);
1711 }
1712
1713 int ref_update_reject_duplicates(struct string_list *refnames,
1714                                  struct strbuf *err)
1715 {
1716         size_t i, n = refnames->nr;
1717
1718         assert(err);
1719
1720         for (i = 1; i < n; i++) {
1721                 int cmp = strcmp(refnames->items[i - 1].string,
1722                                  refnames->items[i].string);
1723
1724                 if (!cmp) {
1725                         strbuf_addf(err,
1726                                     "multiple updates for ref '%s' not allowed.",
1727                                     refnames->items[i].string);
1728                         return 1;
1729                 } else if (cmp > 0) {
1730                         die("BUG: ref_update_reject_duplicates() received unsorted list");
1731                 }
1732         }
1733         return 0;
1734 }
1735
1736 int ref_transaction_prepare(struct ref_transaction *transaction,
1737                             struct strbuf *err)
1738 {
1739         struct ref_store *refs = transaction->ref_store;
1740
1741         switch (transaction->state) {
1742         case REF_TRANSACTION_OPEN:
1743                 /* Good. */
1744                 break;
1745         case REF_TRANSACTION_PREPARED:
1746                 die("BUG: prepare called twice on reference transaction");
1747                 break;
1748         case REF_TRANSACTION_CLOSED:
1749                 die("BUG: prepare called on a closed reference transaction");
1750                 break;
1751         default:
1752                 die("BUG: unexpected reference transaction state");
1753                 break;
1754         }
1755
1756         if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
1757                 strbuf_addstr(err,
1758                               _("ref updates forbidden inside quarantine environment"));
1759                 return -1;
1760         }
1761
1762         return refs->be->transaction_prepare(refs, transaction, err);
1763 }
1764
1765 int ref_transaction_abort(struct ref_transaction *transaction,
1766                           struct strbuf *err)
1767 {
1768         struct ref_store *refs = transaction->ref_store;
1769         int ret = 0;
1770
1771         switch (transaction->state) {
1772         case REF_TRANSACTION_OPEN:
1773                 /* No need to abort explicitly. */
1774                 break;
1775         case REF_TRANSACTION_PREPARED:
1776                 ret = refs->be->transaction_abort(refs, transaction, err);
1777                 break;
1778         case REF_TRANSACTION_CLOSED:
1779                 die("BUG: abort called on a closed reference transaction");
1780                 break;
1781         default:
1782                 die("BUG: unexpected reference transaction state");
1783                 break;
1784         }
1785
1786         ref_transaction_free(transaction);
1787         return ret;
1788 }
1789
1790 int ref_transaction_commit(struct ref_transaction *transaction,
1791                            struct strbuf *err)
1792 {
1793         struct ref_store *refs = transaction->ref_store;
1794         int ret;
1795
1796         switch (transaction->state) {
1797         case REF_TRANSACTION_OPEN:
1798                 /* Need to prepare first. */
1799                 ret = ref_transaction_prepare(transaction, err);
1800                 if (ret)
1801                         return ret;
1802                 break;
1803         case REF_TRANSACTION_PREPARED:
1804                 /* Fall through to finish. */
1805                 break;
1806         case REF_TRANSACTION_CLOSED:
1807                 die("BUG: commit called on a closed reference transaction");
1808                 break;
1809         default:
1810                 die("BUG: unexpected reference transaction state");
1811                 break;
1812         }
1813
1814         return refs->be->transaction_finish(refs, transaction, err);
1815 }
1816
1817 int refs_verify_refname_available(struct ref_store *refs,
1818                                   const char *refname,
1819                                   const struct string_list *extras,
1820                                   const struct string_list *skip,
1821                                   struct strbuf *err)
1822 {
1823         const char *slash;
1824         const char *extra_refname;
1825         struct strbuf dirname = STRBUF_INIT;
1826         struct strbuf referent = STRBUF_INIT;
1827         struct object_id oid;
1828         unsigned int type;
1829         struct ref_iterator *iter;
1830         int ok;
1831         int ret = -1;
1832
1833         /*
1834          * For the sake of comments in this function, suppose that
1835          * refname is "refs/foo/bar".
1836          */
1837
1838         assert(err);
1839
1840         strbuf_grow(&dirname, strlen(refname) + 1);
1841         for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
1842                 /* Expand dirname to the new prefix, not including the trailing slash: */
1843                 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
1844
1845                 /*
1846                  * We are still at a leading dir of the refname (e.g.,
1847                  * "refs/foo"; if there is a reference with that name,
1848                  * it is a conflict, *unless* it is in skip.
1849                  */
1850                 if (skip && string_list_has_string(skip, dirname.buf))
1851                         continue;
1852
1853                 if (!refs_read_raw_ref(refs, dirname.buf, oid.hash, &referent, &type)) {
1854                         strbuf_addf(err, "'%s' exists; cannot create '%s'",
1855                                     dirname.buf, refname);
1856                         goto cleanup;
1857                 }
1858
1859                 if (extras && string_list_has_string(extras, dirname.buf)) {
1860                         strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1861                                     refname, dirname.buf);
1862                         goto cleanup;
1863                 }
1864         }
1865
1866         /*
1867          * We are at the leaf of our refname (e.g., "refs/foo/bar").
1868          * There is no point in searching for a reference with that
1869          * name, because a refname isn't considered to conflict with
1870          * itself. But we still need to check for references whose
1871          * names are in the "refs/foo/bar/" namespace, because they
1872          * *do* conflict.
1873          */
1874         strbuf_addstr(&dirname, refname + dirname.len);
1875         strbuf_addch(&dirname, '/');
1876
1877         iter = refs_ref_iterator_begin(refs, dirname.buf, 0,
1878                                        DO_FOR_EACH_INCLUDE_BROKEN);
1879         while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
1880                 if (skip &&
1881                     string_list_has_string(skip, iter->refname))
1882                         continue;
1883
1884                 strbuf_addf(err, "'%s' exists; cannot create '%s'",
1885                             iter->refname, refname);
1886                 ref_iterator_abort(iter);
1887                 goto cleanup;
1888         }
1889
1890         if (ok != ITER_DONE)
1891                 die("BUG: error while iterating over references");
1892
1893         extra_refname = find_descendant_ref(dirname.buf, extras, skip);
1894         if (extra_refname)
1895                 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1896                             refname, extra_refname);
1897         else
1898                 ret = 0;
1899
1900 cleanup:
1901         strbuf_release(&referent);
1902         strbuf_release(&dirname);
1903         return ret;
1904 }
1905
1906 int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1907 {
1908         struct ref_iterator *iter;
1909
1910         iter = refs->be->reflog_iterator_begin(refs);
1911
1912         return do_for_each_ref_iterator(iter, fn, cb_data);
1913 }
1914
1915 int for_each_reflog(each_ref_fn fn, void *cb_data)
1916 {
1917         return refs_for_each_reflog(get_main_ref_store(), fn, cb_data);
1918 }
1919
1920 int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
1921                                      const char *refname,
1922                                      each_reflog_ent_fn fn,
1923                                      void *cb_data)
1924 {
1925         return refs->be->for_each_reflog_ent_reverse(refs, refname,
1926                                                      fn, cb_data);
1927 }
1928
1929 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
1930                                 void *cb_data)
1931 {
1932         return refs_for_each_reflog_ent_reverse(get_main_ref_store(),
1933                                                 refname, fn, cb_data);
1934 }
1935
1936 int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
1937                              each_reflog_ent_fn fn, void *cb_data)
1938 {
1939         return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
1940 }
1941
1942 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
1943                         void *cb_data)
1944 {
1945         return refs_for_each_reflog_ent(get_main_ref_store(), refname,
1946                                         fn, cb_data);
1947 }
1948
1949 int refs_reflog_exists(struct ref_store *refs, const char *refname)
1950 {
1951         return refs->be->reflog_exists(refs, refname);
1952 }
1953
1954 int reflog_exists(const char *refname)
1955 {
1956         return refs_reflog_exists(get_main_ref_store(), refname);
1957 }
1958
1959 int refs_create_reflog(struct ref_store *refs, const char *refname,
1960                        int force_create, struct strbuf *err)
1961 {
1962         return refs->be->create_reflog(refs, refname, force_create, err);
1963 }
1964
1965 int safe_create_reflog(const char *refname, int force_create,
1966                        struct strbuf *err)
1967 {
1968         return refs_create_reflog(get_main_ref_store(), refname,
1969                                   force_create, err);
1970 }
1971
1972 int refs_delete_reflog(struct ref_store *refs, const char *refname)
1973 {
1974         return refs->be->delete_reflog(refs, refname);
1975 }
1976
1977 int delete_reflog(const char *refname)
1978 {
1979         return refs_delete_reflog(get_main_ref_store(), refname);
1980 }
1981
1982 int refs_reflog_expire(struct ref_store *refs,
1983                        const char *refname, const unsigned char *sha1,
1984                        unsigned int flags,
1985                        reflog_expiry_prepare_fn prepare_fn,
1986                        reflog_expiry_should_prune_fn should_prune_fn,
1987                        reflog_expiry_cleanup_fn cleanup_fn,
1988                        void *policy_cb_data)
1989 {
1990         return refs->be->reflog_expire(refs, refname, sha1, flags,
1991                                        prepare_fn, should_prune_fn,
1992                                        cleanup_fn, policy_cb_data);
1993 }
1994
1995 int reflog_expire(const char *refname, const unsigned char *sha1,
1996                   unsigned int flags,
1997                   reflog_expiry_prepare_fn prepare_fn,
1998                   reflog_expiry_should_prune_fn should_prune_fn,
1999                   reflog_expiry_cleanup_fn cleanup_fn,
2000                   void *policy_cb_data)
2001 {
2002         return refs_reflog_expire(get_main_ref_store(),
2003                                   refname, sha1, flags,
2004                                   prepare_fn, should_prune_fn,
2005                                   cleanup_fn, policy_cb_data);
2006 }
2007
2008 int initial_ref_transaction_commit(struct ref_transaction *transaction,
2009                                    struct strbuf *err)
2010 {
2011         struct ref_store *refs = transaction->ref_store;
2012
2013         return refs->be->initial_transaction_commit(refs, transaction, err);
2014 }
2015
2016 int refs_delete_refs(struct ref_store *refs, const char *msg,
2017                      struct string_list *refnames, unsigned int flags)
2018 {
2019         return refs->be->delete_refs(refs, msg, refnames, flags);
2020 }
2021
2022 int delete_refs(const char *msg, struct string_list *refnames,
2023                 unsigned int flags)
2024 {
2025         return refs_delete_refs(get_main_ref_store(), msg, refnames, flags);
2026 }
2027
2028 int refs_rename_ref(struct ref_store *refs, const char *oldref,
2029                     const char *newref, const char *logmsg)
2030 {
2031         return refs->be->rename_ref(refs, oldref, newref, logmsg);
2032 }
2033
2034 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
2035 {
2036         return refs_rename_ref(get_main_ref_store(), oldref, newref, logmsg);
2037 }