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

   1 /*
   2  * The backend-independent part of the reference module.
   3  */
   4
   5 #include "cache.h"
   6 #include "config.h"
   7 #include "hashmap.h"
   8 #include "lockfile.h"
   9 #include "iterator.h"
  10 #include "refs.h"
  11 #include "refs/refs-internal.h"
  12 #include "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 char *refs_resolve_refdup(struct ref_store *refs,
 178                           const char *refname, int resolve_flags,
 179                           unsigned char *sha1, int *flags)
 180 {
 181         const char *result;
 182
 183         result = refs_resolve_ref_unsafe(refs, refname, resolve_flags,
 184                                          sha1, flags);
 185         return xstrdup_or_null(result);
 186 }
 187
 188 char *resolve_refdup(const char *refname, int resolve_flags,
 189                      unsigned char *sha1, int *flags)
 190 {
 191         return refs_resolve_refdup(get_main_ref_store(),
 192                                    refname, resolve_flags,
 193                                    sha1, flags);
 194 }
 195
 196 /* The argument to filter_refs */
 197 struct ref_filter {
 198         const char *pattern;
 199         each_ref_fn *fn;
 200         void *cb_data;
 201 };
 202
 203 int refs_read_ref_full(struct ref_store *refs, const char *refname,
 204                        int resolve_flags, unsigned char *sha1, int *flags)
 205 {
 206         if (refs_resolve_ref_unsafe(refs, refname, resolve_flags, sha1, flags))
 207                 return 0;
 208         return -1;
 209 }
 210
 211 int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
 212 {
 213         return refs_read_ref_full(get_main_ref_store(), refname,
 214                                   resolve_flags, sha1, flags);
 215 }
 216
 217 int read_ref(const char *refname, unsigned char *sha1)
 218 {
 219         return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
 220 }
 221
 222 int ref_exists(const char *refname)
 223 {
 224         unsigned char sha1[20];
 225         return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
 226 }
 227
 228 static int filter_refs(const char *refname, const struct object_id *oid,
 229                            int flags, void *data)
 230 {
 231         struct ref_filter *filter = (struct ref_filter *)data;
 232
 233         if (wildmatch(filter->pattern, refname, 0))
 234                 return 0;
 235         return filter->fn(refname, oid, flags, filter->cb_data);
 236 }
 237
 238 enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
 239 {
 240         struct object *o = lookup_unknown_object(name);
 241
 242         if (o->type == OBJ_NONE) {
 243                 int type = sha1_object_info(name, NULL);
 244                 if (type < 0 || !object_as_type(o, type, 0))
 245                         return PEEL_INVALID;
 246         }
 247
 248         if (o->type != OBJ_TAG)
 249                 return PEEL_NON_TAG;
 250
 251         o = deref_tag_noverify(o);
 252         if (!o)
 253                 return PEEL_INVALID;
 254
 255         hashcpy(sha1, o->oid.hash);
 256         return PEEL_PEELED;
 257 }
 258
 259 struct warn_if_dangling_data {
 260         FILE *fp;
 261         const char *refname;
 262         const struct string_list *refnames;
 263         const char *msg_fmt;
 264 };
 265
 266 static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
 267                                    int flags, void *cb_data)
 268 {
 269         struct warn_if_dangling_data *d = cb_data;
 270         const char *resolves_to;
 271         struct object_id junk;
 272
 273         if (!(flags & REF_ISSYMREF))
 274                 return 0;
 275
 276         resolves_to = resolve_ref_unsafe(refname, 0, junk.hash, NULL);
 277         if (!resolves_to
 278             || (d->refname
 279                 ? strcmp(resolves_to, d->refname)
 280                 : !string_list_has_string(d->refnames, resolves_to))) {
 281                 return 0;
 282         }
 283
 284         fprintf(d->fp, d->msg_fmt, refname);
 285         fputc('\n', d->fp);
 286         return 0;
 287 }
 288
 289 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 290 {
 291         struct warn_if_dangling_data data;
 292
 293         data.fp = fp;
 294         data.refname = refname;
 295         data.refnames = NULL;
 296         data.msg_fmt = msg_fmt;
 297         for_each_rawref(warn_if_dangling_symref, &data);
 298 }
 299
 300 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
 301 {
 302         struct warn_if_dangling_data data;
 303
 304         data.fp = fp;
 305         data.refname = NULL;
 306         data.refnames = refnames;
 307         data.msg_fmt = msg_fmt;
 308         for_each_rawref(warn_if_dangling_symref, &data);
 309 }
 310
 311 int refs_for_each_tag_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 312 {
 313         return refs_for_each_ref_in(refs, "refs/tags/", fn, cb_data);
 314 }
 315
 316 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 317 {
 318         return refs_for_each_tag_ref(get_main_ref_store(), fn, cb_data);
 319 }
 320
 321 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 322 {
 323         return refs_for_each_tag_ref(get_submodule_ref_store(submodule),
 324                                      fn, cb_data);
 325 }
 326
 327 int refs_for_each_branch_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 328 {
 329         return refs_for_each_ref_in(refs, "refs/heads/", fn, cb_data);
 330 }
 331
 332 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 333 {
 334         return refs_for_each_branch_ref(get_main_ref_store(), fn, cb_data);
 335 }
 336
 337 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 338 {
 339         return refs_for_each_branch_ref(get_submodule_ref_store(submodule),
 340                                         fn, cb_data);
 341 }
 342
 343 int refs_for_each_remote_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 344 {
 345         return refs_for_each_ref_in(refs, "refs/remotes/", fn, cb_data);
 346 }
 347
 348 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 349 {
 350         return refs_for_each_remote_ref(get_main_ref_store(), fn, cb_data);
 351 }
 352
 353 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 354 {
 355         return refs_for_each_remote_ref(get_submodule_ref_store(submodule),
 356                                         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 static int write_pseudoref(const char *pseudoref, const unsigned char *sha1,
 565                            const unsigned char *old_sha1, struct strbuf *err)
 566 {
 567         const char *filename;
 568         int fd;
 569         static struct lock_file lock;
 570         struct strbuf buf = STRBUF_INIT;
 571         int ret = -1;
 572
 573         strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
 574
 575         filename = git_path("%s", pseudoref);
 576         fd = hold_lock_file_for_update(&lock, filename, LOCK_DIE_ON_ERROR);
 577         if (fd < 0) {
 578                 strbuf_addf(err, "could not open '%s' for writing: %s",
 579                             filename, strerror(errno));
 580                 return -1;
 581         }
 582
 583         if (old_sha1) {
 584                 unsigned char actual_old_sha1[20];
 585
 586                 if (read_ref(pseudoref, actual_old_sha1))
 587                         die("could not read ref '%s'", pseudoref);
 588                 if (hashcmp(actual_old_sha1, old_sha1)) {
 589                         strbuf_addf(err, "unexpected sha1 when writing '%s'", pseudoref);
 590                         rollback_lock_file(&lock);
 591                         goto done;
 592                 }
 593         }
 594
 595         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 596                 strbuf_addf(err, "could not write to '%s'", filename);
 597                 rollback_lock_file(&lock);
 598                 goto done;
 599         }
 600
 601         commit_lock_file(&lock);
 602         ret = 0;
 603 done:
 604         strbuf_release(&buf);
 605         return ret;
 606 }
 607
 608 static int delete_pseudoref(const char *pseudoref, const unsigned char *old_sha1)
 609 {
 610         static struct lock_file lock;
 611         const char *filename;
 612
 613         filename = git_path("%s", pseudoref);
 614
 615         if (old_sha1 && !is_null_sha1(old_sha1)) {
 616                 int fd;
 617                 unsigned char actual_old_sha1[20];
 618
 619                 fd = hold_lock_file_for_update(&lock, filename,
 620                                                LOCK_DIE_ON_ERROR);
 621                 if (fd < 0)
 622                         die_errno(_("Could not open '%s' for writing"), filename);
 623                 if (read_ref(pseudoref, actual_old_sha1))
 624                         die("could not read ref '%s'", pseudoref);
 625                 if (hashcmp(actual_old_sha1, old_sha1)) {
 626                         warning("Unexpected sha1 when deleting %s", pseudoref);
 627                         rollback_lock_file(&lock);
 628                         return -1;
 629                 }
 630
 631                 unlink(filename);
 632                 rollback_lock_file(&lock);
 633         } else {
 634                 unlink(filename);
 635         }
 636
 637         return 0;
 638 }
 639
 640 int refs_delete_ref(struct ref_store *refs, const char *msg,
 641                     const char *refname,
 642                     const unsigned char *old_sha1,
 643                     unsigned int flags)
 644 {
 645         struct ref_transaction *transaction;
 646         struct strbuf err = STRBUF_INIT;
 647
 648         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
 649                 assert(refs == get_main_ref_store());
 650                 return delete_pseudoref(refname, old_sha1);
 651         }
 652
 653         transaction = ref_store_transaction_begin(refs, &err);
 654         if (!transaction ||
 655             ref_transaction_delete(transaction, refname, old_sha1,
 656                                    flags, msg, &err) ||
 657             ref_transaction_commit(transaction, &err)) {
 658                 error("%s", err.buf);
 659                 ref_transaction_free(transaction);
 660                 strbuf_release(&err);
 661                 return 1;
 662         }
 663         ref_transaction_free(transaction);
 664         strbuf_release(&err);
 665         return 0;
 666 }
 667
 668 int delete_ref(const char *msg, const char *refname,
 669                const unsigned char *old_sha1, unsigned int flags)
 670 {
 671         return refs_delete_ref(get_main_ref_store(), msg, refname,
 672                                old_sha1, flags);
 673 }
 674
 675 int copy_reflog_msg(char *buf, const char *msg)
 676 {
 677         char *cp = buf;
 678         char c;
 679         int wasspace = 1;
 680
 681         *cp++ = '\t';
 682         while ((c = *msg++)) {
 683                 if (wasspace && isspace(c))
 684                         continue;
 685                 wasspace = isspace(c);
 686                 if (wasspace)
 687                         c = ' ';
 688                 *cp++ = c;
 689         }
 690         while (buf < cp && isspace(cp[-1]))
 691                 cp--;
 692         *cp++ = '\n';
 693         return cp - buf;
 694 }
 695
 696 int should_autocreate_reflog(const char *refname)
 697 {
 698         switch (log_all_ref_updates) {
 699         case LOG_REFS_ALWAYS:
 700                 return 1;
 701         case LOG_REFS_NORMAL:
 702                 return starts_with(refname, "refs/heads/") ||
 703                         starts_with(refname, "refs/remotes/") ||
 704                         starts_with(refname, "refs/notes/") ||
 705                         !strcmp(refname, "HEAD");
 706         default:
 707                 return 0;
 708         }
 709 }
 710
 711 int is_branch(const char *refname)
 712 {
 713         return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
 714 }
 715
 716 struct read_ref_at_cb {
 717         const char *refname;
 718         timestamp_t at_time;
 719         int cnt;
 720         int reccnt;
 721         unsigned char *sha1;
 722         int found_it;
 723
 724         unsigned char osha1[20];
 725         unsigned char nsha1[20];
 726         int tz;
 727         timestamp_t date;
 728         char **msg;
 729         timestamp_t *cutoff_time;
 730         int *cutoff_tz;
 731         int *cutoff_cnt;
 732 };
 733
 734 static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
 735                 const char *email, timestamp_t timestamp, int tz,
 736                 const char *message, void *cb_data)
 737 {
 738         struct read_ref_at_cb *cb = cb_data;
 739
 740         cb->reccnt++;
 741         cb->tz = tz;
 742         cb->date = timestamp;
 743
 744         if (timestamp <= cb->at_time || cb->cnt == 0) {
 745                 if (cb->msg)
 746                         *cb->msg = xstrdup(message);
 747                 if (cb->cutoff_time)
 748                         *cb->cutoff_time = timestamp;
 749                 if (cb->cutoff_tz)
 750                         *cb->cutoff_tz = tz;
 751                 if (cb->cutoff_cnt)
 752                         *cb->cutoff_cnt = cb->reccnt - 1;
 753                 /*
 754                  * we have not yet updated cb->[n|o]sha1 so they still
 755                  * hold the values for the previous record.
 756                  */
 757                 if (!is_null_sha1(cb->osha1)) {
 758                         hashcpy(cb->sha1, noid->hash);
 759                         if (hashcmp(cb->osha1, noid->hash))
 760                                 warning("Log for ref %s has gap after %s.",
 761                                         cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
 762                 }
 763                 else if (cb->date == cb->at_time)
 764                         hashcpy(cb->sha1, noid->hash);
 765                 else if (hashcmp(noid->hash, cb->sha1))
 766                         warning("Log for ref %s unexpectedly ended on %s.",
 767                                 cb->refname, show_date(cb->date, cb->tz,
 768                                                        DATE_MODE(RFC2822)));
 769                 hashcpy(cb->osha1, ooid->hash);
 770                 hashcpy(cb->nsha1, noid->hash);
 771                 cb->found_it = 1;
 772                 return 1;
 773         }
 774         hashcpy(cb->osha1, ooid->hash);
 775         hashcpy(cb->nsha1, noid->hash);
 776         if (cb->cnt > 0)
 777                 cb->cnt--;
 778         return 0;
 779 }
 780
 781 static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
 782                                   const char *email, timestamp_t timestamp,
 783                                   int tz, const char *message, void *cb_data)
 784 {
 785         struct read_ref_at_cb *cb = cb_data;
 786
 787         if (cb->msg)
 788                 *cb->msg = xstrdup(message);
 789         if (cb->cutoff_time)
 790                 *cb->cutoff_time = timestamp;
 791         if (cb->cutoff_tz)
 792                 *cb->cutoff_tz = tz;
 793         if (cb->cutoff_cnt)
 794                 *cb->cutoff_cnt = cb->reccnt;
 795         hashcpy(cb->sha1, ooid->hash);
 796         if (is_null_sha1(cb->sha1))
 797                 hashcpy(cb->sha1, noid->hash);
 798         /* We just want the first entry */
 799         return 1;
 800 }
 801
 802 int read_ref_at(const char *refname, unsigned int flags, timestamp_t at_time, int cnt,
 803                 unsigned char *sha1, char **msg,
 804                 timestamp_t *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
 805 {
 806         struct read_ref_at_cb cb;
 807
 808         memset(&cb, 0, sizeof(cb));
 809         cb.refname = refname;
 810         cb.at_time = at_time;
 811         cb.cnt = cnt;
 812         cb.msg = msg;
 813         cb.cutoff_time = cutoff_time;
 814         cb.cutoff_tz = cutoff_tz;
 815         cb.cutoff_cnt = cutoff_cnt;
 816         cb.sha1 = sha1;
 817
 818         for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
 819
 820         if (!cb.reccnt) {
 821                 if (flags & GET_SHA1_QUIETLY)
 822                         exit(128);
 823                 else
 824                         die("Log for %s is empty.", refname);
 825         }
 826         if (cb.found_it)
 827                 return 0;
 828
 829         for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
 830
 831         return 1;
 832 }
 833
 834 struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
 835                                                     struct strbuf *err)
 836 {
 837         struct ref_transaction *tr;
 838         assert(err);
 839
 840         tr = xcalloc(1, sizeof(struct ref_transaction));
 841         tr->ref_store = refs;
 842         return tr;
 843 }
 844
 845 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 846 {
 847         return ref_store_transaction_begin(get_main_ref_store(), err);
 848 }
 849
 850 void ref_transaction_free(struct ref_transaction *transaction)
 851 {
 852         size_t i;
 853
 854         if (!transaction)
 855                 return;
 856
 857         switch (transaction->state) {
 858         case REF_TRANSACTION_OPEN:
 859         case REF_TRANSACTION_CLOSED:
 860                 /* OK */
 861                 break;
 862         case REF_TRANSACTION_PREPARED:
 863                 die("BUG: free called on a prepared reference transaction");
 864                 break;
 865         default:
 866                 die("BUG: unexpected reference transaction state");
 867                 break;
 868         }
 869
 870         for (i = 0; i < transaction->nr; i++) {
 871                 free(transaction->updates[i]->msg);
 872                 free(transaction->updates[i]);
 873         }
 874         free(transaction->updates);
 875         free(transaction);
 876 }
 877
 878 struct ref_update *ref_transaction_add_update(
 879                 struct ref_transaction *transaction,
 880                 const char *refname, unsigned int flags,
 881                 const unsigned char *new_sha1,
 882                 const unsigned char *old_sha1,
 883                 const char *msg)
 884 {
 885         struct ref_update *update;
 886
 887         if (transaction->state != REF_TRANSACTION_OPEN)
 888                 die("BUG: update called for transaction that is not open");
 889
 890         if ((flags & REF_ISPRUNING) && !(flags & REF_NODEREF))
 891                 die("BUG: REF_ISPRUNING set without REF_NODEREF");
 892
 893         FLEX_ALLOC_STR(update, refname, refname);
 894         ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
 895         transaction->updates[transaction->nr++] = update;
 896
 897         update->flags = flags;
 898
 899         if (flags & REF_HAVE_NEW)
 900                 hashcpy(update->new_oid.hash, new_sha1);
 901         if (flags & REF_HAVE_OLD)
 902                 hashcpy(update->old_oid.hash, old_sha1);
 903         update->msg = xstrdup_or_null(msg);
 904         return update;
 905 }
 906
 907 int ref_transaction_update(struct ref_transaction *transaction,
 908                            const char *refname,
 909                            const unsigned char *new_sha1,
 910                            const unsigned char *old_sha1,
 911                            unsigned int flags, const char *msg,
 912                            struct strbuf *err)
 913 {
 914         assert(err);
 915
 916         if ((new_sha1 && !is_null_sha1(new_sha1)) ?
 917             check_refname_format(refname, REFNAME_ALLOW_ONELEVEL) :
 918             !refname_is_safe(refname)) {
 919                 strbuf_addf(err, "refusing to update ref with bad name '%s'",
 920                             refname);
 921                 return -1;
 922         }
 923
 924         flags &= REF_TRANSACTION_UPDATE_ALLOWED_FLAGS;
 925
 926         flags |= (new_sha1 ? REF_HAVE_NEW : 0) | (old_sha1 ? REF_HAVE_OLD : 0);
 927
 928         ref_transaction_add_update(transaction, refname, flags,
 929                                    new_sha1, old_sha1, msg);
 930         return 0;
 931 }
 932
 933 int ref_transaction_create(struct ref_transaction *transaction,
 934                            const char *refname,
 935                            const unsigned char *new_sha1,
 936                            unsigned int flags, const char *msg,
 937                            struct strbuf *err)
 938 {
 939         if (!new_sha1 || is_null_sha1(new_sha1))
 940                 die("BUG: create called without valid new_sha1");
 941         return ref_transaction_update(transaction, refname, new_sha1,
 942                                       null_sha1, flags, msg, err);
 943 }
 944
 945 int ref_transaction_delete(struct ref_transaction *transaction,
 946                            const char *refname,
 947                            const unsigned char *old_sha1,
 948                            unsigned int flags, const char *msg,
 949                            struct strbuf *err)
 950 {
 951         if (old_sha1 && is_null_sha1(old_sha1))
 952                 die("BUG: delete called with old_sha1 set to zeros");
 953         return ref_transaction_update(transaction, refname,
 954                                       null_sha1, old_sha1,
 955                                       flags, msg, err);
 956 }
 957
 958 int ref_transaction_verify(struct ref_transaction *transaction,
 959                            const char *refname,
 960                            const unsigned char *old_sha1,
 961                            unsigned int flags,
 962                            struct strbuf *err)
 963 {
 964         if (!old_sha1)
 965                 die("BUG: verify called with old_sha1 set to NULL");
 966         return ref_transaction_update(transaction, refname,
 967                                       NULL, old_sha1,
 968                                       flags, NULL, err);
 969 }
 970
 971 int update_ref_oid(const char *msg, const char *refname,
 972                const struct object_id *new_oid, const struct object_id *old_oid,
 973                unsigned int flags, enum action_on_err onerr)
 974 {
 975         return update_ref(msg, refname, new_oid ? new_oid->hash : NULL,
 976                 old_oid ? old_oid->hash : NULL, flags, onerr);
 977 }
 978
 979 int refs_update_ref(struct ref_store *refs, const char *msg,
 980                     const char *refname, const unsigned char *new_sha1,
 981                     const unsigned char *old_sha1, unsigned int flags,
 982                     enum action_on_err onerr)
 983 {
 984         struct ref_transaction *t = NULL;
 985         struct strbuf err = STRBUF_INIT;
 986         int ret = 0;
 987
 988         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
 989                 assert(refs == get_main_ref_store());
 990                 ret = write_pseudoref(refname, new_sha1, old_sha1, &err);
 991         } else {
 992                 t = ref_store_transaction_begin(refs, &err);
 993                 if (!t ||
 994                     ref_transaction_update(t, refname, new_sha1, old_sha1,
 995                                            flags, msg, &err) ||
 996                     ref_transaction_commit(t, &err)) {
 997                         ret = 1;
 998                         ref_transaction_free(t);
 999                 }
1000         }
1001         if (ret) {
1002                 const char *str = "update_ref failed for ref '%s': %s";
1003
1004                 switch (onerr) {
1005                 case UPDATE_REFS_MSG_ON_ERR:
1006                         error(str, refname, err.buf);
1007                         break;
1008                 case UPDATE_REFS_DIE_ON_ERR:
1009                         die(str, refname, err.buf);
1010                         break;
1011                 case UPDATE_REFS_QUIET_ON_ERR:
1012                         break;
1013                 }
1014                 strbuf_release(&err);
1015                 return 1;
1016         }
1017         strbuf_release(&err);
1018         if (t)
1019                 ref_transaction_free(t);
1020         return 0;
1021 }
1022
1023 int update_ref(const char *msg, const char *refname,
1024                const unsigned char *new_sha1,
1025                const unsigned char *old_sha1,
1026                unsigned int flags, enum action_on_err onerr)
1027 {
1028         return refs_update_ref(get_main_ref_store(), msg, refname, new_sha1,
1029                                old_sha1, flags, onerr);
1030 }
1031
1032 char *shorten_unambiguous_ref(const char *refname, int strict)
1033 {
1034         int i;
1035         static char **scanf_fmts;
1036         static int nr_rules;
1037         char *short_name;
1038         struct strbuf resolved_buf = STRBUF_INIT;
1039
1040         if (!nr_rules) {
1041                 /*
1042                  * Pre-generate scanf formats from ref_rev_parse_rules[].
1043                  * Generate a format suitable for scanf from a
1044                  * ref_rev_parse_rules rule by interpolating "%s" at the
1045                  * location of the "%.*s".
1046                  */
1047                 size_t total_len = 0;
1048                 size_t offset = 0;
1049
1050                 /* the rule list is NULL terminated, count them first */
1051                 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
1052                         /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
1053                         total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
1054
1055                 scanf_fmts = xmalloc(st_add(st_mult(sizeof(char *), nr_rules), total_len));
1056
1057                 offset = 0;
1058                 for (i = 0; i < nr_rules; i++) {
1059                         assert(offset < total_len);
1060                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
1061                         offset += snprintf(scanf_fmts[i], total_len - offset,
1062                                            ref_rev_parse_rules[i], 2, "%s") + 1;
1063                 }
1064         }
1065
1066         /* bail out if there are no rules */
1067         if (!nr_rules)
1068                 return xstrdup(refname);
1069
1070         /* buffer for scanf result, at most refname must fit */
1071         short_name = xstrdup(refname);
1072
1073         /* skip first rule, it will always match */
1074         for (i = nr_rules - 1; i > 0 ; --i) {
1075                 int j;
1076                 int rules_to_fail = i;
1077                 int short_name_len;
1078
1079                 if (1 != sscanf(refname, scanf_fmts[i], short_name))
1080                         continue;
1081
1082                 short_name_len = strlen(short_name);
1083
1084                 /*
1085                  * in strict mode, all (except the matched one) rules
1086                  * must fail to resolve to a valid non-ambiguous ref
1087                  */
1088                 if (strict)
1089                         rules_to_fail = nr_rules;
1090
1091                 /*
1092                  * check if the short name resolves to a valid ref,
1093                  * but use only rules prior to the matched one
1094                  */
1095                 for (j = 0; j < rules_to_fail; j++) {
1096                         const char *rule = ref_rev_parse_rules[j];
1097
1098                         /* skip matched rule */
1099                         if (i == j)
1100                                 continue;
1101
1102                         /*
1103                          * the short name is ambiguous, if it resolves
1104                          * (with this previous rule) to a valid ref
1105                          * read_ref() returns 0 on success
1106                          */
1107                         strbuf_reset(&resolved_buf);
1108                         strbuf_addf(&resolved_buf, rule,
1109                                     short_name_len, short_name);
1110                         if (ref_exists(resolved_buf.buf))
1111                                 break;
1112                 }
1113
1114                 /*
1115                  * short name is non-ambiguous if all previous rules
1116                  * haven't resolved to a valid ref
1117                  */
1118                 if (j == rules_to_fail) {
1119                         strbuf_release(&resolved_buf);
1120                         return short_name;
1121                 }
1122         }
1123
1124         strbuf_release(&resolved_buf);
1125         free(short_name);
1126         return xstrdup(refname);
1127 }
1128
1129 static struct string_list *hide_refs;
1130
1131 int parse_hide_refs_config(const char *var, const char *value, const char *section)
1132 {
1133         const char *key;
1134         if (!strcmp("transfer.hiderefs", var) ||
1135             (!parse_config_key(var, section, NULL, NULL, &key) &&
1136              !strcmp(key, "hiderefs"))) {
1137                 char *ref;
1138                 int len;
1139
1140                 if (!value)
1141                         return config_error_nonbool(var);
1142                 ref = xstrdup(value);
1143                 len = strlen(ref);
1144                 while (len && ref[len - 1] == '/')
1145                         ref[--len] = '\0';
1146                 if (!hide_refs) {
1147                         hide_refs = xcalloc(1, sizeof(*hide_refs));
1148                         hide_refs->strdup_strings = 1;
1149                 }
1150                 string_list_append(hide_refs, ref);
1151         }
1152         return 0;
1153 }
1154
1155 int ref_is_hidden(const char *refname, const char *refname_full)
1156 {
1157         int i;
1158
1159         if (!hide_refs)
1160                 return 0;
1161         for (i = hide_refs->nr - 1; i >= 0; i--) {
1162                 const char *match = hide_refs->items[i].string;
1163                 const char *subject;
1164                 int neg = 0;
1165                 const char *p;
1166
1167                 if (*match == '!') {
1168                         neg = 1;
1169                         match++;
1170                 }
1171
1172                 if (*match == '^') {
1173                         subject = refname_full;
1174                         match++;
1175                 } else {
1176                         subject = refname;
1177                 }
1178
1179                 /* refname can be NULL when namespaces are used. */
1180                 if (subject &&
1181                     skip_prefix(subject, match, &p) &&
1182                     (!*p || *p == '/'))
1183                         return !neg;
1184         }
1185         return 0;
1186 }
1187
1188 const char *find_descendant_ref(const char *dirname,
1189                                 const struct string_list *extras,
1190                                 const struct string_list *skip)
1191 {
1192         int pos;
1193
1194         if (!extras)
1195                 return NULL;
1196
1197         /*
1198          * Look at the place where dirname would be inserted into
1199          * extras. If there is an entry at that position that starts
1200          * with dirname (remember, dirname includes the trailing
1201          * slash) and is not in skip, then we have a conflict.
1202          */
1203         for (pos = string_list_find_insert_index(extras, dirname, 0);
1204              pos < extras->nr; pos++) {
1205                 const char *extra_refname = extras->items[pos].string;
1206
1207                 if (!starts_with(extra_refname, dirname))
1208                         break;
1209
1210                 if (!skip || !string_list_has_string(skip, extra_refname))
1211                         return extra_refname;
1212         }
1213         return NULL;
1214 }
1215
1216 int refs_rename_ref_available(struct ref_store *refs,
1217                               const char *old_refname,
1218                               const char *new_refname)
1219 {
1220         struct string_list skip = STRING_LIST_INIT_NODUP;
1221         struct strbuf err = STRBUF_INIT;
1222         int ok;
1223
1224         string_list_insert(&skip, old_refname);
1225         ok = !refs_verify_refname_available(refs, new_refname,
1226                                             NULL, &skip, &err);
1227         if (!ok)
1228                 error("%s", err.buf);
1229
1230         string_list_clear(&skip, 0);
1231         strbuf_release(&err);
1232         return ok;
1233 }
1234
1235 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1236 {
1237         struct object_id oid;
1238         int flag;
1239
1240         if (submodule) {
1241                 if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
1242                         return fn("HEAD", &oid, 0, cb_data);
1243
1244                 return 0;
1245         }
1246
1247         if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
1248                 return fn("HEAD", &oid, flag, cb_data);
1249
1250         return 0;
1251 }
1252
1253 int head_ref(each_ref_fn fn, void *cb_data)
1254 {
1255         return head_ref_submodule(NULL, fn, cb_data);
1256 }
1257
1258 struct ref_iterator *refs_ref_iterator_begin(
1259                 struct ref_store *refs,
1260                 const char *prefix, int trim, int flags)
1261 {
1262         struct ref_iterator *iter;
1263
1264         if (ref_paranoia < 0)
1265                 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1266         if (ref_paranoia)
1267                 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1268
1269         iter = refs->be->iterator_begin(refs, prefix, flags);
1270
1271         /*
1272          * `iterator_begin()` already takes care of prefix, but we
1273          * might need to do some trimming:
1274          */
1275         if (trim)
1276                 iter = prefix_ref_iterator_begin(iter, "", trim);
1277
1278         return iter;
1279 }
1280
1281 /*
1282  * Call fn for each reference in the specified submodule for which the
1283  * refname begins with prefix. If trim is non-zero, then trim that
1284  * many characters off the beginning of each refname before passing
1285  * the refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to
1286  * include broken references in the iteration. If fn ever returns a
1287  * non-zero value, stop the iteration and return that value;
1288  * otherwise, return 0.
1289  */
1290 static int do_for_each_ref(struct ref_store *refs, const char *prefix,
1291                            each_ref_fn fn, int trim, int flags, void *cb_data)
1292 {
1293         struct ref_iterator *iter;
1294
1295         if (!refs)
1296                 return 0;
1297
1298         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1299
1300         return do_for_each_ref_iterator(iter, fn, cb_data);
1301 }
1302
1303 int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1304 {
1305         return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
1306 }
1307
1308 int for_each_ref(each_ref_fn fn, void *cb_data)
1309 {
1310         return refs_for_each_ref(get_main_ref_store(), fn, cb_data);
1311 }
1312
1313 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1314 {
1315         return refs_for_each_ref(get_submodule_ref_store(submodule), fn, cb_data);
1316 }
1317
1318 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
1319                          each_ref_fn fn, void *cb_data)
1320 {
1321         return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
1322 }
1323
1324 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1325 {
1326         return refs_for_each_ref_in(get_main_ref_store(), prefix, fn, cb_data);
1327 }
1328
1329 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1330 {
1331         unsigned int flag = 0;
1332
1333         if (broken)
1334                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1335         return do_for_each_ref(get_main_ref_store(),
1336                                prefix, fn, 0, flag, cb_data);
1337 }
1338
1339 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1340                               each_ref_fn fn, void *cb_data)
1341 {
1342         return refs_for_each_ref_in(get_submodule_ref_store(submodule),
1343                                     prefix, fn, cb_data);
1344 }
1345
1346 int for_each_fullref_in_submodule(const char *submodule, 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(get_submodule_ref_store(submodule),
1355                                prefix, fn, 0, flag, cb_data);
1356 }
1357
1358 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1359 {
1360         return do_for_each_ref(get_main_ref_store(),
1361                                git_replace_ref_base, fn,
1362                                strlen(git_replace_ref_base),
1363                                0, cb_data);
1364 }
1365
1366 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1367 {
1368         struct strbuf buf = STRBUF_INIT;
1369         int ret;
1370         strbuf_addf(&buf, "%srefs/", get_git_namespace());
1371         ret = do_for_each_ref(get_main_ref_store(),
1372                               buf.buf, fn, 0, 0, cb_data);
1373         strbuf_release(&buf);
1374         return ret;
1375 }
1376
1377 int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1378 {
1379         return do_for_each_ref(refs, "", fn, 0,
1380                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1381 }
1382
1383 int for_each_rawref(each_ref_fn fn, void *cb_data)
1384 {
1385         return refs_for_each_rawref(get_main_ref_store(), fn, cb_data);
1386 }
1387
1388 int refs_read_raw_ref(struct ref_store *ref_store,
1389                       const char *refname, unsigned char *sha1,
1390                       struct strbuf *referent, unsigned int *type)
1391 {
1392         return ref_store->be->read_raw_ref(ref_store, refname, sha1, referent, type);
1393 }
1394
1395 /* This function needs to return a meaningful errno on failure */
1396 const char *refs_resolve_ref_unsafe(struct ref_store *refs,
1397                                     const char *refname,
1398                                     int resolve_flags,
1399                                     unsigned char *sha1, int *flags)
1400 {
1401         static struct strbuf sb_refname = STRBUF_INIT;
1402         int unused_flags;
1403         int symref_count;
1404
1405         if (!flags)
1406                 flags = &unused_flags;
1407
1408         *flags = 0;
1409
1410         if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1411                 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1412                     !refname_is_safe(refname)) {
1413                         errno = EINVAL;
1414                         return NULL;
1415                 }
1416
1417                 /*
1418                  * dwim_ref() uses REF_ISBROKEN to distinguish between
1419                  * missing refs and refs that were present but invalid,
1420                  * to complain about the latter to stderr.
1421                  *
1422                  * We don't know whether the ref exists, so don't set
1423                  * REF_ISBROKEN yet.
1424                  */
1425                 *flags |= REF_BAD_NAME;
1426         }
1427
1428         for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
1429                 unsigned int read_flags = 0;
1430
1431                 if (refs_read_raw_ref(refs, refname,
1432                                       sha1, &sb_refname, &read_flags)) {
1433                         *flags |= read_flags;
1434                         if (errno != ENOENT || (resolve_flags & RESOLVE_REF_READING))
1435                                 return NULL;
1436                         hashclr(sha1);
1437                         if (*flags & REF_BAD_NAME)
1438                                 *flags |= REF_ISBROKEN;
1439                         return refname;
1440                 }
1441
1442                 *flags |= read_flags;
1443
1444                 if (!(read_flags & REF_ISSYMREF)) {
1445                         if (*flags & REF_BAD_NAME) {
1446                                 hashclr(sha1);
1447                                 *flags |= REF_ISBROKEN;
1448                         }
1449                         return refname;
1450                 }
1451
1452                 refname = sb_refname.buf;
1453                 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1454                         hashclr(sha1);
1455                         return refname;
1456                 }
1457                 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1458                         if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1459                             !refname_is_safe(refname)) {
1460                                 errno = EINVAL;
1461                                 return NULL;
1462                         }
1463
1464                         *flags |= REF_ISBROKEN | REF_BAD_NAME;
1465                 }
1466         }
1467
1468         errno = ELOOP;
1469         return NULL;
1470 }
1471
1472 /* backend functions */
1473 int refs_init_db(struct strbuf *err)
1474 {
1475         struct ref_store *refs = get_main_ref_store();
1476
1477         return refs->be->init_db(refs, err);
1478 }
1479
1480 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1481                                unsigned char *sha1, int *flags)
1482 {
1483         return refs_resolve_ref_unsafe(get_main_ref_store(), refname,
1484                                        resolve_flags, sha1, flags);
1485 }
1486
1487 int resolve_gitlink_ref(const char *submodule, const char *refname,
1488                         unsigned char *sha1)
1489 {
1490         size_t len = strlen(submodule);
1491         struct ref_store *refs;
1492         int flags;
1493
1494         while (len && submodule[len - 1] == '/')
1495                 len--;
1496
1497         if (!len)
1498                 return -1;
1499
1500         if (submodule[len]) {
1501                 /* We need to strip off one or more trailing slashes */
1502                 char *stripped = xmemdupz(submodule, len);
1503
1504                 refs = get_submodule_ref_store(stripped);
1505                 free(stripped);
1506         } else {
1507                 refs = get_submodule_ref_store(submodule);
1508         }
1509
1510         if (!refs)
1511                 return -1;
1512
1513         if (!refs_resolve_ref_unsafe(refs, refname, 0, sha1, &flags) ||
1514             is_null_sha1(sha1))
1515                 return -1;
1516         return 0;
1517 }
1518
1519 struct ref_store_hash_entry
1520 {
1521         struct hashmap_entry ent; /* must be the first member! */
1522
1523         struct ref_store *refs;
1524
1525         /* NUL-terminated identifier of the ref store: */
1526         char name[FLEX_ARRAY];
1527 };
1528
1529 static int ref_store_hash_cmp(const void *unused_cmp_data,
1530                               const void *entry, const void *entry_or_key,
1531                               const void *keydata)
1532 {
1533         const struct ref_store_hash_entry *e1 = entry, *e2 = entry_or_key;
1534         const char *name = keydata ? keydata : e2->name;
1535
1536         return strcmp(e1->name, name);
1537 }
1538
1539 static struct ref_store_hash_entry *alloc_ref_store_hash_entry(
1540                 const char *name, struct ref_store *refs)
1541 {
1542         struct ref_store_hash_entry *entry;
1543
1544         FLEX_ALLOC_STR(entry, name, name);
1545         hashmap_entry_init(entry, strhash(name));
1546         entry->refs = refs;
1547         return entry;
1548 }
1549
1550 /* A pointer to the ref_store for the main repository: */
1551 static struct ref_store *main_ref_store;
1552
1553 /* A hashmap of ref_stores, stored by submodule name: */
1554 static struct hashmap submodule_ref_stores;
1555
1556 /* A hashmap of ref_stores, stored by worktree id: */
1557 static struct hashmap worktree_ref_stores;
1558
1559 /*
1560  * Look up a ref store by name. If that ref_store hasn't been
1561  * registered yet, return NULL.
1562  */
1563 static struct ref_store *lookup_ref_store_map(struct hashmap *map,
1564                                               const char *name)
1565 {
1566         struct ref_store_hash_entry *entry;
1567
1568         if (!map->tablesize)
1569                 /* It's initialized on demand in register_ref_store(). */
1570                 return NULL;
1571
1572         entry = hashmap_get_from_hash(map, strhash(name), name);
1573         return entry ? entry->refs : NULL;
1574 }
1575
1576 /*
1577  * Create, record, and return a ref_store instance for the specified
1578  * gitdir.
1579  */
1580 static struct ref_store *ref_store_init(const char *gitdir,
1581                                         unsigned int flags)
1582 {
1583         const char *be_name = "files";
1584         struct ref_storage_be *be = find_ref_storage_backend(be_name);
1585         struct ref_store *refs;
1586
1587         if (!be)
1588                 die("BUG: reference backend %s is unknown", be_name);
1589
1590         refs = be->init(gitdir, flags);
1591         return refs;
1592 }
1593
1594 struct ref_store *get_main_ref_store(void)
1595 {
1596         if (main_ref_store)
1597                 return main_ref_store;
1598
1599         main_ref_store = ref_store_init(get_git_dir(), REF_STORE_ALL_CAPS);
1600         return main_ref_store;
1601 }
1602
1603 /*
1604  * Associate a ref store with a name. It is a fatal error to call this
1605  * function twice for the same name.
1606  */
1607 static void register_ref_store_map(struct hashmap *map,
1608                                    const char *type,
1609                                    struct ref_store *refs,
1610                                    const char *name)
1611 {
1612         if (!map->tablesize)
1613                 hashmap_init(map, ref_store_hash_cmp, NULL, 0);
1614
1615         if (hashmap_put(map, alloc_ref_store_hash_entry(name, refs)))
1616                 die("BUG: %s ref_store '%s' initialized twice", type, name);
1617 }
1618
1619 struct ref_store *get_submodule_ref_store(const char *submodule)
1620 {
1621         struct strbuf submodule_sb = STRBUF_INIT;
1622         struct ref_store *refs;
1623         int ret;
1624
1625         if (!submodule || !*submodule) {
1626                 /*
1627                  * FIXME: This case is ideally not allowed. But that
1628                  * can't happen until we clean up all the callers.
1629                  */
1630                 return get_main_ref_store();
1631         }
1632
1633         refs = lookup_ref_store_map(&submodule_ref_stores, submodule);
1634         if (refs)
1635                 return refs;
1636
1637         strbuf_addstr(&submodule_sb, submodule);
1638         ret = is_nonbare_repository_dir(&submodule_sb);
1639         strbuf_release(&submodule_sb);
1640         if (!ret)
1641                 return NULL;
1642
1643         ret = submodule_to_gitdir(&submodule_sb, submodule);
1644         if (ret) {
1645                 strbuf_release(&submodule_sb);
1646                 return NULL;
1647         }
1648
1649         /* assume that add_submodule_odb() has been called */
1650         refs = ref_store_init(submodule_sb.buf,
1651                               REF_STORE_READ | REF_STORE_ODB);
1652         register_ref_store_map(&submodule_ref_stores, "submodule",
1653                                refs, submodule);
1654
1655         strbuf_release(&submodule_sb);
1656         return refs;
1657 }
1658
1659 struct ref_store *get_worktree_ref_store(const struct worktree *wt)
1660 {
1661         struct ref_store *refs;
1662         const char *id;
1663
1664         if (wt->is_current)
1665                 return get_main_ref_store();
1666
1667         id = wt->id ? wt->id : "/";
1668         refs = lookup_ref_store_map(&worktree_ref_stores, id);
1669         if (refs)
1670                 return refs;
1671
1672         if (wt->id)
1673                 refs = ref_store_init(git_common_path("worktrees/%s", wt->id),
1674                                       REF_STORE_ALL_CAPS);
1675         else
1676                 refs = ref_store_init(get_git_common_dir(),
1677                                       REF_STORE_ALL_CAPS);
1678
1679         if (refs)
1680                 register_ref_store_map(&worktree_ref_stores, "worktree",
1681                                        refs, id);
1682         return refs;
1683 }
1684
1685 void base_ref_store_init(struct ref_store *refs,
1686                          const struct ref_storage_be *be)
1687 {
1688         refs->be = be;
1689 }
1690
1691 /* backend functions */
1692 int refs_pack_refs(struct ref_store *refs, unsigned int flags)
1693 {
1694         return refs->be->pack_refs(refs, flags);
1695 }
1696
1697 int refs_peel_ref(struct ref_store *refs, const char *refname,
1698                   unsigned char *sha1)
1699 {
1700         return refs->be->peel_ref(refs, refname, sha1);
1701 }
1702
1703 int peel_ref(const char *refname, unsigned char *sha1)
1704 {
1705         return refs_peel_ref(get_main_ref_store(), refname, sha1);
1706 }
1707
1708 int refs_create_symref(struct ref_store *refs,
1709                        const char *ref_target,
1710                        const char *refs_heads_master,
1711                        const char *logmsg)
1712 {
1713         return refs->be->create_symref(refs, ref_target,
1714                                        refs_heads_master,
1715                                        logmsg);
1716 }
1717
1718 int create_symref(const char *ref_target, const char *refs_heads_master,
1719                   const char *logmsg)
1720 {
1721         return refs_create_symref(get_main_ref_store(), ref_target,
1722                                   refs_heads_master, logmsg);
1723 }
1724
1725 int ref_update_reject_duplicates(struct string_list *refnames,
1726                                  struct strbuf *err)
1727 {
1728         size_t i, n = refnames->nr;
1729
1730         assert(err);
1731
1732         for (i = 1; i < n; i++) {
1733                 int cmp = strcmp(refnames->items[i - 1].string,
1734                                  refnames->items[i].string);
1735
1736                 if (!cmp) {
1737                         strbuf_addf(err,
1738                                     "multiple updates for ref '%s' not allowed.",
1739                                     refnames->items[i].string);
1740                         return 1;
1741                 } else if (cmp > 0) {
1742                         die("BUG: ref_update_reject_duplicates() received unsorted list");
1743                 }
1744         }
1745         return 0;
1746 }
1747
1748 int ref_transaction_prepare(struct ref_transaction *transaction,
1749                             struct strbuf *err)
1750 {
1751         struct ref_store *refs = transaction->ref_store;
1752
1753         switch (transaction->state) {
1754         case REF_TRANSACTION_OPEN:
1755                 /* Good. */
1756                 break;
1757         case REF_TRANSACTION_PREPARED:
1758                 die("BUG: prepare called twice on reference transaction");
1759                 break;
1760         case REF_TRANSACTION_CLOSED:
1761                 die("BUG: prepare called on a closed reference transaction");
1762                 break;
1763         default:
1764                 die("BUG: unexpected reference transaction state");
1765                 break;
1766         }
1767
1768         if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
1769                 strbuf_addstr(err,
1770                               _("ref updates forbidden inside quarantine environment"));
1771                 return -1;
1772         }
1773
1774         return refs->be->transaction_prepare(refs, transaction, err);
1775 }
1776
1777 int ref_transaction_abort(struct ref_transaction *transaction,
1778                           struct strbuf *err)
1779 {
1780         struct ref_store *refs = transaction->ref_store;
1781         int ret = 0;
1782
1783         switch (transaction->state) {
1784         case REF_TRANSACTION_OPEN:
1785                 /* No need to abort explicitly. */
1786                 break;
1787         case REF_TRANSACTION_PREPARED:
1788                 ret = refs->be->transaction_abort(refs, transaction, err);
1789                 break;
1790         case REF_TRANSACTION_CLOSED:
1791                 die("BUG: abort called on a closed reference transaction");
1792                 break;
1793         default:
1794                 die("BUG: unexpected reference transaction state");
1795                 break;
1796         }
1797
1798         ref_transaction_free(transaction);
1799         return ret;
1800 }
1801
1802 int ref_transaction_commit(struct ref_transaction *transaction,
1803                            struct strbuf *err)
1804 {
1805         struct ref_store *refs = transaction->ref_store;
1806         int ret;
1807
1808         switch (transaction->state) {
1809         case REF_TRANSACTION_OPEN:
1810                 /* Need to prepare first. */
1811                 ret = ref_transaction_prepare(transaction, err);
1812                 if (ret)
1813                         return ret;
1814                 break;
1815         case REF_TRANSACTION_PREPARED:
1816                 /* Fall through to finish. */
1817                 break;
1818         case REF_TRANSACTION_CLOSED:
1819                 die("BUG: commit called on a closed reference transaction");
1820                 break;
1821         default:
1822                 die("BUG: unexpected reference transaction state");
1823                 break;
1824         }
1825
1826         return refs->be->transaction_finish(refs, transaction, err);
1827 }
1828
1829 int refs_verify_refname_available(struct ref_store *refs,
1830                                   const char *refname,
1831                                   const struct string_list *extras,
1832                                   const struct string_list *skip,
1833                                   struct strbuf *err)
1834 {
1835         const char *slash;
1836         const char *extra_refname;
1837         struct strbuf dirname = STRBUF_INIT;
1838         struct strbuf referent = STRBUF_INIT;
1839         struct object_id oid;
1840         unsigned int type;
1841         struct ref_iterator *iter;
1842         int ok;
1843         int ret = -1;
1844
1845         /*
1846          * For the sake of comments in this function, suppose that
1847          * refname is "refs/foo/bar".
1848          */
1849
1850         assert(err);
1851
1852         strbuf_grow(&dirname, strlen(refname) + 1);
1853         for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
1854                 /* Expand dirname to the new prefix, not including the trailing slash: */
1855                 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
1856
1857                 /*
1858                  * We are still at a leading dir of the refname (e.g.,
1859                  * "refs/foo"; if there is a reference with that name,
1860                  * it is a conflict, *unless* it is in skip.
1861                  */
1862                 if (skip && string_list_has_string(skip, dirname.buf))
1863                         continue;
1864
1865                 if (!refs_read_raw_ref(refs, dirname.buf, oid.hash, &referent, &type)) {
1866                         strbuf_addf(err, "'%s' exists; cannot create '%s'",
1867                                     dirname.buf, refname);
1868                         goto cleanup;
1869                 }
1870
1871                 if (extras && string_list_has_string(extras, dirname.buf)) {
1872                         strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1873                                     refname, dirname.buf);
1874                         goto cleanup;
1875                 }
1876         }
1877
1878         /*
1879          * We are at the leaf of our refname (e.g., "refs/foo/bar").
1880          * There is no point in searching for a reference with that
1881          * name, because a refname isn't considered to conflict with
1882          * itself. But we still need to check for references whose
1883          * names are in the "refs/foo/bar/" namespace, because they
1884          * *do* conflict.
1885          */
1886         strbuf_addstr(&dirname, refname + dirname.len);
1887         strbuf_addch(&dirname, '/');
1888
1889         iter = refs_ref_iterator_begin(refs, dirname.buf, 0,
1890                                        DO_FOR_EACH_INCLUDE_BROKEN);
1891         while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
1892                 if (skip &&
1893                     string_list_has_string(skip, iter->refname))
1894                         continue;
1895
1896                 strbuf_addf(err, "'%s' exists; cannot create '%s'",
1897                             iter->refname, refname);
1898                 ref_iterator_abort(iter);
1899                 goto cleanup;
1900         }
1901
1902         if (ok != ITER_DONE)
1903                 die("BUG: error while iterating over references");
1904
1905         extra_refname = find_descendant_ref(dirname.buf, extras, skip);
1906         if (extra_refname)
1907                 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1908                             refname, extra_refname);
1909         else
1910                 ret = 0;
1911
1912 cleanup:
1913         strbuf_release(&referent);
1914         strbuf_release(&dirname);
1915         return ret;
1916 }
1917
1918 int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1919 {
1920         struct ref_iterator *iter;
1921
1922         iter = refs->be->reflog_iterator_begin(refs);
1923
1924         return do_for_each_ref_iterator(iter, fn, cb_data);
1925 }
1926
1927 int for_each_reflog(each_ref_fn fn, void *cb_data)
1928 {
1929         return refs_for_each_reflog(get_main_ref_store(), fn, cb_data);
1930 }
1931
1932 int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
1933                                      const char *refname,
1934                                      each_reflog_ent_fn fn,
1935                                      void *cb_data)
1936 {
1937         return refs->be->for_each_reflog_ent_reverse(refs, refname,
1938                                                      fn, cb_data);
1939 }
1940
1941 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
1942                                 void *cb_data)
1943 {
1944         return refs_for_each_reflog_ent_reverse(get_main_ref_store(),
1945                                                 refname, fn, cb_data);
1946 }
1947
1948 int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
1949                              each_reflog_ent_fn fn, void *cb_data)
1950 {
1951         return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
1952 }
1953
1954 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
1955                         void *cb_data)
1956 {
1957         return refs_for_each_reflog_ent(get_main_ref_store(), refname,
1958                                         fn, cb_data);
1959 }
1960
1961 int refs_reflog_exists(struct ref_store *refs, const char *refname)
1962 {
1963         return refs->be->reflog_exists(refs, refname);
1964 }
1965
1966 int reflog_exists(const char *refname)
1967 {
1968         return refs_reflog_exists(get_main_ref_store(), refname);
1969 }
1970
1971 int refs_create_reflog(struct ref_store *refs, const char *refname,
1972                        int force_create, struct strbuf *err)
1973 {
1974         return refs->be->create_reflog(refs, refname, force_create, err);
1975 }
1976
1977 int safe_create_reflog(const char *refname, int force_create,
1978                        struct strbuf *err)
1979 {
1980         return refs_create_reflog(get_main_ref_store(), refname,
1981                                   force_create, err);
1982 }
1983
1984 int refs_delete_reflog(struct ref_store *refs, const char *refname)
1985 {
1986         return refs->be->delete_reflog(refs, refname);
1987 }
1988
1989 int delete_reflog(const char *refname)
1990 {
1991         return refs_delete_reflog(get_main_ref_store(), refname);
1992 }
1993
1994 int refs_reflog_expire(struct ref_store *refs,
1995                        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->be->reflog_expire(refs, refname, sha1, flags,
2003                                        prepare_fn, should_prune_fn,
2004                                        cleanup_fn, policy_cb_data);
2005 }
2006
2007 int reflog_expire(const char *refname, const unsigned char *sha1,
2008                   unsigned int flags,
2009                   reflog_expiry_prepare_fn prepare_fn,
2010                   reflog_expiry_should_prune_fn should_prune_fn,
2011                   reflog_expiry_cleanup_fn cleanup_fn,
2012                   void *policy_cb_data)
2013 {
2014         return refs_reflog_expire(get_main_ref_store(),
2015                                   refname, sha1, flags,
2016                                   prepare_fn, should_prune_fn,
2017                                   cleanup_fn, policy_cb_data);
2018 }
2019
2020 int initial_ref_transaction_commit(struct ref_transaction *transaction,
2021                                    struct strbuf *err)
2022 {
2023         struct ref_store *refs = transaction->ref_store;
2024
2025         return refs->be->initial_transaction_commit(refs, transaction, err);
2026 }
2027
2028 int refs_delete_refs(struct ref_store *refs, const char *msg,
2029                      struct string_list *refnames, unsigned int flags)
2030 {
2031         return refs->be->delete_refs(refs, msg, refnames, flags);
2032 }
2033
2034 int delete_refs(const char *msg, struct string_list *refnames,
2035                 unsigned int flags)
2036 {
2037         return refs_delete_refs(get_main_ref_store(), msg, refnames, flags);
2038 }
2039
2040 int refs_rename_ref(struct ref_store *refs, const char *oldref,
2041                     const char *newref, const char *logmsg)
2042 {
2043         return refs->be->rename_ref(refs, oldref, newref, logmsg);
2044 }
2045
2046 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
2047 {
2048         return refs_rename_ref(get_main_ref_store(), oldref, newref, logmsg);
2049 }