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) != buf.len) {
 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 |= (new_sha1 ? REF_HAVE_NEW : 0) | (old_sha1 ? REF_HAVE_OLD : 0);
 925
 926         ref_transaction_add_update(transaction, refname, flags,
 927                                    new_sha1, old_sha1, msg);
 928         return 0;
 929 }
 930
 931 int ref_transaction_create(struct ref_transaction *transaction,
 932                            const char *refname,
 933                            const unsigned char *new_sha1,
 934                            unsigned int flags, const char *msg,
 935                            struct strbuf *err)
 936 {
 937         if (!new_sha1 || is_null_sha1(new_sha1))
 938                 die("BUG: create called without valid new_sha1");
 939         return ref_transaction_update(transaction, refname, new_sha1,
 940                                       null_sha1, flags, msg, err);
 941 }
 942
 943 int ref_transaction_delete(struct ref_transaction *transaction,
 944                            const char *refname,
 945                            const unsigned char *old_sha1,
 946                            unsigned int flags, const char *msg,
 947                            struct strbuf *err)
 948 {
 949         if (old_sha1 && is_null_sha1(old_sha1))
 950                 die("BUG: delete called with old_sha1 set to zeros");
 951         return ref_transaction_update(transaction, refname,
 952                                       null_sha1, old_sha1,
 953                                       flags, msg, err);
 954 }
 955
 956 int ref_transaction_verify(struct ref_transaction *transaction,
 957                            const char *refname,
 958                            const unsigned char *old_sha1,
 959                            unsigned int flags,
 960                            struct strbuf *err)
 961 {
 962         if (!old_sha1)
 963                 die("BUG: verify called with old_sha1 set to NULL");
 964         return ref_transaction_update(transaction, refname,
 965                                       NULL, old_sha1,
 966                                       flags, NULL, err);
 967 }
 968
 969 int update_ref_oid(const char *msg, const char *refname,
 970                const struct object_id *new_oid, const struct object_id *old_oid,
 971                unsigned int flags, enum action_on_err onerr)
 972 {
 973         return update_ref(msg, refname, new_oid ? new_oid->hash : NULL,
 974                 old_oid ? old_oid->hash : NULL, flags, onerr);
 975 }
 976
 977 int refs_update_ref(struct ref_store *refs, const char *msg,
 978                     const char *refname, const unsigned char *new_sha1,
 979                     const unsigned char *old_sha1, unsigned int flags,
 980                     enum action_on_err onerr)
 981 {
 982         struct ref_transaction *t = NULL;
 983         struct strbuf err = STRBUF_INIT;
 984         int ret = 0;
 985
 986         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
 987                 assert(refs == get_main_ref_store());
 988                 ret = write_pseudoref(refname, new_sha1, old_sha1, &err);
 989         } else {
 990                 t = ref_store_transaction_begin(refs, &err);
 991                 if (!t ||
 992                     ref_transaction_update(t, refname, new_sha1, old_sha1,
 993                                            flags, msg, &err) ||
 994                     ref_transaction_commit(t, &err)) {
 995                         ret = 1;
 996                         ref_transaction_free(t);
 997                 }
 998         }
 999         if (ret) {
1000                 const char *str = "update_ref failed for ref '%s': %s";
1001
1002                 switch (onerr) {
1003                 case UPDATE_REFS_MSG_ON_ERR:
1004                         error(str, refname, err.buf);
1005                         break;
1006                 case UPDATE_REFS_DIE_ON_ERR:
1007                         die(str, refname, err.buf);
1008                         break;
1009                 case UPDATE_REFS_QUIET_ON_ERR:
1010                         break;
1011                 }
1012                 strbuf_release(&err);
1013                 return 1;
1014         }
1015         strbuf_release(&err);
1016         if (t)
1017                 ref_transaction_free(t);
1018         return 0;
1019 }
1020
1021 int update_ref(const char *msg, const char *refname,
1022                const unsigned char *new_sha1,
1023                const unsigned char *old_sha1,
1024                unsigned int flags, enum action_on_err onerr)
1025 {
1026         return refs_update_ref(get_main_ref_store(), msg, refname, new_sha1,
1027                                old_sha1, flags, onerr);
1028 }
1029
1030 char *shorten_unambiguous_ref(const char *refname, int strict)
1031 {
1032         int i;
1033         static char **scanf_fmts;
1034         static int nr_rules;
1035         char *short_name;
1036         struct strbuf resolved_buf = STRBUF_INIT;
1037
1038         if (!nr_rules) {
1039                 /*
1040                  * Pre-generate scanf formats from ref_rev_parse_rules[].
1041                  * Generate a format suitable for scanf from a
1042                  * ref_rev_parse_rules rule by interpolating "%s" at the
1043                  * location of the "%.*s".
1044                  */
1045                 size_t total_len = 0;
1046                 size_t offset = 0;
1047
1048                 /* the rule list is NULL terminated, count them first */
1049                 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
1050                         /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
1051                         total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
1052
1053                 scanf_fmts = xmalloc(st_add(st_mult(sizeof(char *), nr_rules), total_len));
1054
1055                 offset = 0;
1056                 for (i = 0; i < nr_rules; i++) {
1057                         assert(offset < total_len);
1058                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
1059                         offset += snprintf(scanf_fmts[i], total_len - offset,
1060                                            ref_rev_parse_rules[i], 2, "%s") + 1;
1061                 }
1062         }
1063
1064         /* bail out if there are no rules */
1065         if (!nr_rules)
1066                 return xstrdup(refname);
1067
1068         /* buffer for scanf result, at most refname must fit */
1069         short_name = xstrdup(refname);
1070
1071         /* skip first rule, it will always match */
1072         for (i = nr_rules - 1; i > 0 ; --i) {
1073                 int j;
1074                 int rules_to_fail = i;
1075                 int short_name_len;
1076
1077                 if (1 != sscanf(refname, scanf_fmts[i], short_name))
1078                         continue;
1079
1080                 short_name_len = strlen(short_name);
1081
1082                 /*
1083                  * in strict mode, all (except the matched one) rules
1084                  * must fail to resolve to a valid non-ambiguous ref
1085                  */
1086                 if (strict)
1087                         rules_to_fail = nr_rules;
1088
1089                 /*
1090                  * check if the short name resolves to a valid ref,
1091                  * but use only rules prior to the matched one
1092                  */
1093                 for (j = 0; j < rules_to_fail; j++) {
1094                         const char *rule = ref_rev_parse_rules[j];
1095
1096                         /* skip matched rule */
1097                         if (i == j)
1098                                 continue;
1099
1100                         /*
1101                          * the short name is ambiguous, if it resolves
1102                          * (with this previous rule) to a valid ref
1103                          * read_ref() returns 0 on success
1104                          */
1105                         strbuf_reset(&resolved_buf);
1106                         strbuf_addf(&resolved_buf, rule,
1107                                     short_name_len, short_name);
1108                         if (ref_exists(resolved_buf.buf))
1109                                 break;
1110                 }
1111
1112                 /*
1113                  * short name is non-ambiguous if all previous rules
1114                  * haven't resolved to a valid ref
1115                  */
1116                 if (j == rules_to_fail) {
1117                         strbuf_release(&resolved_buf);
1118                         return short_name;
1119                 }
1120         }
1121
1122         strbuf_release(&resolved_buf);
1123         free(short_name);
1124         return xstrdup(refname);
1125 }
1126
1127 static struct string_list *hide_refs;
1128
1129 int parse_hide_refs_config(const char *var, const char *value, const char *section)
1130 {
1131         const char *key;
1132         if (!strcmp("transfer.hiderefs", var) ||
1133             (!parse_config_key(var, section, NULL, NULL, &key) &&
1134              !strcmp(key, "hiderefs"))) {
1135                 char *ref;
1136                 int len;
1137
1138                 if (!value)
1139                         return config_error_nonbool(var);
1140                 ref = xstrdup(value);
1141                 len = strlen(ref);
1142                 while (len && ref[len - 1] == '/')
1143                         ref[--len] = '\0';
1144                 if (!hide_refs) {
1145                         hide_refs = xcalloc(1, sizeof(*hide_refs));
1146                         hide_refs->strdup_strings = 1;
1147                 }
1148                 string_list_append(hide_refs, ref);
1149         }
1150         return 0;
1151 }
1152
1153 int ref_is_hidden(const char *refname, const char *refname_full)
1154 {
1155         int i;
1156
1157         if (!hide_refs)
1158                 return 0;
1159         for (i = hide_refs->nr - 1; i >= 0; i--) {
1160                 const char *match = hide_refs->items[i].string;
1161                 const char *subject;
1162                 int neg = 0;
1163                 const char *p;
1164
1165                 if (*match == '!') {
1166                         neg = 1;
1167                         match++;
1168                 }
1169
1170                 if (*match == '^') {
1171                         subject = refname_full;
1172                         match++;
1173                 } else {
1174                         subject = refname;
1175                 }
1176
1177                 /* refname can be NULL when namespaces are used. */
1178                 if (subject &&
1179                     skip_prefix(subject, match, &p) &&
1180                     (!*p || *p == '/'))
1181                         return !neg;
1182         }
1183         return 0;
1184 }
1185
1186 const char *find_descendant_ref(const char *dirname,
1187                                 const struct string_list *extras,
1188                                 const struct string_list *skip)
1189 {
1190         int pos;
1191
1192         if (!extras)
1193                 return NULL;
1194
1195         /*
1196          * Look at the place where dirname would be inserted into
1197          * extras. If there is an entry at that position that starts
1198          * with dirname (remember, dirname includes the trailing
1199          * slash) and is not in skip, then we have a conflict.
1200          */
1201         for (pos = string_list_find_insert_index(extras, dirname, 0);
1202              pos < extras->nr; pos++) {
1203                 const char *extra_refname = extras->items[pos].string;
1204
1205                 if (!starts_with(extra_refname, dirname))
1206                         break;
1207
1208                 if (!skip || !string_list_has_string(skip, extra_refname))
1209                         return extra_refname;
1210         }
1211         return NULL;
1212 }
1213
1214 int refs_rename_ref_available(struct ref_store *refs,
1215                               const char *old_refname,
1216                               const char *new_refname)
1217 {
1218         struct string_list skip = STRING_LIST_INIT_NODUP;
1219         struct strbuf err = STRBUF_INIT;
1220         int ok;
1221
1222         string_list_insert(&skip, old_refname);
1223         ok = !refs_verify_refname_available(refs, new_refname,
1224                                             NULL, &skip, &err);
1225         if (!ok)
1226                 error("%s", err.buf);
1227
1228         string_list_clear(&skip, 0);
1229         strbuf_release(&err);
1230         return ok;
1231 }
1232
1233 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1234 {
1235         struct object_id oid;
1236         int flag;
1237
1238         if (submodule) {
1239                 if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
1240                         return fn("HEAD", &oid, 0, cb_data);
1241
1242                 return 0;
1243         }
1244
1245         if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
1246                 return fn("HEAD", &oid, flag, cb_data);
1247
1248         return 0;
1249 }
1250
1251 int head_ref(each_ref_fn fn, void *cb_data)
1252 {
1253         return head_ref_submodule(NULL, fn, cb_data);
1254 }
1255
1256 struct ref_iterator *refs_ref_iterator_begin(
1257                 struct ref_store *refs,
1258                 const char *prefix, int trim, int flags)
1259 {
1260         struct ref_iterator *iter;
1261
1262         if (ref_paranoia < 0)
1263                 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1264         if (ref_paranoia)
1265                 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1266
1267         iter = refs->be->iterator_begin(refs, prefix, flags);
1268
1269         /*
1270          * `iterator_begin()` already takes care of prefix, but we
1271          * might need to do some trimming:
1272          */
1273         if (trim)
1274                 iter = prefix_ref_iterator_begin(iter, "", trim);
1275
1276         return iter;
1277 }
1278
1279 /*
1280  * Call fn for each reference in the specified submodule for which the
1281  * refname begins with prefix. If trim is non-zero, then trim that
1282  * many characters off the beginning of each refname before passing
1283  * the refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to
1284  * include broken references in the iteration. If fn ever returns a
1285  * non-zero value, stop the iteration and return that value;
1286  * otherwise, return 0.
1287  */
1288 static int do_for_each_ref(struct ref_store *refs, const char *prefix,
1289                            each_ref_fn fn, int trim, int flags, void *cb_data)
1290 {
1291         struct ref_iterator *iter;
1292
1293         if (!refs)
1294                 return 0;
1295
1296         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1297
1298         return do_for_each_ref_iterator(iter, fn, cb_data);
1299 }
1300
1301 int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1302 {
1303         return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
1304 }
1305
1306 int for_each_ref(each_ref_fn fn, void *cb_data)
1307 {
1308         return refs_for_each_ref(get_main_ref_store(), fn, cb_data);
1309 }
1310
1311 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1312 {
1313         return refs_for_each_ref(get_submodule_ref_store(submodule), fn, cb_data);
1314 }
1315
1316 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
1317                          each_ref_fn fn, void *cb_data)
1318 {
1319         return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
1320 }
1321
1322 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1323 {
1324         return refs_for_each_ref_in(get_main_ref_store(), prefix, fn, cb_data);
1325 }
1326
1327 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1328 {
1329         unsigned int flag = 0;
1330
1331         if (broken)
1332                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1333         return do_for_each_ref(get_main_ref_store(),
1334                                prefix, fn, 0, flag, cb_data);
1335 }
1336
1337 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1338                               each_ref_fn fn, void *cb_data)
1339 {
1340         return refs_for_each_ref_in(get_submodule_ref_store(submodule),
1341                                     prefix, fn, cb_data);
1342 }
1343
1344 int for_each_fullref_in_submodule(const char *submodule, const char *prefix,
1345                                   each_ref_fn fn, void *cb_data,
1346                                   unsigned int broken)
1347 {
1348         unsigned int flag = 0;
1349
1350         if (broken)
1351                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1352         return do_for_each_ref(get_submodule_ref_store(submodule),
1353                                prefix, fn, 0, flag, cb_data);
1354 }
1355
1356 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1357 {
1358         return do_for_each_ref(get_main_ref_store(),
1359                                git_replace_ref_base, fn,
1360                                strlen(git_replace_ref_base),
1361                                0, cb_data);
1362 }
1363
1364 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1365 {
1366         struct strbuf buf = STRBUF_INIT;
1367         int ret;
1368         strbuf_addf(&buf, "%srefs/", get_git_namespace());
1369         ret = do_for_each_ref(get_main_ref_store(),
1370                               buf.buf, fn, 0, 0, cb_data);
1371         strbuf_release(&buf);
1372         return ret;
1373 }
1374
1375 int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1376 {
1377         return do_for_each_ref(refs, "", fn, 0,
1378                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1379 }
1380
1381 int for_each_rawref(each_ref_fn fn, void *cb_data)
1382 {
1383         return refs_for_each_rawref(get_main_ref_store(), fn, cb_data);
1384 }
1385
1386 int refs_read_raw_ref(struct ref_store *ref_store,
1387                       const char *refname, unsigned char *sha1,
1388                       struct strbuf *referent, unsigned int *type)
1389 {
1390         return ref_store->be->read_raw_ref(ref_store, refname, sha1, referent, type);
1391 }
1392
1393 /* This function needs to return a meaningful errno on failure */
1394 const char *refs_resolve_ref_unsafe(struct ref_store *refs,
1395                                     const char *refname,
1396                                     int resolve_flags,
1397                                     unsigned char *sha1, int *flags)
1398 {
1399         static struct strbuf sb_refname = STRBUF_INIT;
1400         int unused_flags;
1401         int symref_count;
1402
1403         if (!flags)
1404                 flags = &unused_flags;
1405
1406         *flags = 0;
1407
1408         if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1409                 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1410                     !refname_is_safe(refname)) {
1411                         errno = EINVAL;
1412                         return NULL;
1413                 }
1414
1415                 /*
1416                  * dwim_ref() uses REF_ISBROKEN to distinguish between
1417                  * missing refs and refs that were present but invalid,
1418                  * to complain about the latter to stderr.
1419                  *
1420                  * We don't know whether the ref exists, so don't set
1421                  * REF_ISBROKEN yet.
1422                  */
1423                 *flags |= REF_BAD_NAME;
1424         }
1425
1426         for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
1427                 unsigned int read_flags = 0;
1428
1429                 if (refs_read_raw_ref(refs, refname,
1430                                       sha1, &sb_refname, &read_flags)) {
1431                         *flags |= read_flags;
1432                         if (errno != ENOENT || (resolve_flags & RESOLVE_REF_READING))
1433                                 return NULL;
1434                         hashclr(sha1);
1435                         if (*flags & REF_BAD_NAME)
1436                                 *flags |= REF_ISBROKEN;
1437                         return refname;
1438                 }
1439
1440                 *flags |= read_flags;
1441
1442                 if (!(read_flags & REF_ISSYMREF)) {
1443                         if (*flags & REF_BAD_NAME) {
1444                                 hashclr(sha1);
1445                                 *flags |= REF_ISBROKEN;
1446                         }
1447                         return refname;
1448                 }
1449
1450                 refname = sb_refname.buf;
1451                 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1452                         hashclr(sha1);
1453                         return refname;
1454                 }
1455                 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1456                         if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1457                             !refname_is_safe(refname)) {
1458                                 errno = EINVAL;
1459                                 return NULL;
1460                         }
1461
1462                         *flags |= REF_ISBROKEN | REF_BAD_NAME;
1463                 }
1464         }
1465
1466         errno = ELOOP;
1467         return NULL;
1468 }
1469
1470 /* backend functions */
1471 int refs_init_db(struct strbuf *err)
1472 {
1473         struct ref_store *refs = get_main_ref_store();
1474
1475         return refs->be->init_db(refs, err);
1476 }
1477
1478 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1479                                unsigned char *sha1, int *flags)
1480 {
1481         return refs_resolve_ref_unsafe(get_main_ref_store(), refname,
1482                                        resolve_flags, sha1, flags);
1483 }
1484
1485 int resolve_gitlink_ref(const char *submodule, const char *refname,
1486                         unsigned char *sha1)
1487 {
1488         size_t len = strlen(submodule);
1489         struct ref_store *refs;
1490         int flags;
1491
1492         while (len && submodule[len - 1] == '/')
1493                 len--;
1494
1495         if (!len)
1496                 return -1;
1497
1498         if (submodule[len]) {
1499                 /* We need to strip off one or more trailing slashes */
1500                 char *stripped = xmemdupz(submodule, len);
1501
1502                 refs = get_submodule_ref_store(stripped);
1503                 free(stripped);
1504         } else {
1505                 refs = get_submodule_ref_store(submodule);
1506         }
1507
1508         if (!refs)
1509                 return -1;
1510
1511         if (!refs_resolve_ref_unsafe(refs, refname, 0, sha1, &flags) ||
1512             is_null_sha1(sha1))
1513                 return -1;
1514         return 0;
1515 }
1516
1517 struct ref_store_hash_entry
1518 {
1519         struct hashmap_entry ent; /* must be the first member! */
1520
1521         struct ref_store *refs;
1522
1523         /* NUL-terminated identifier of the ref store: */
1524         char name[FLEX_ARRAY];
1525 };
1526
1527 static int ref_store_hash_cmp(const void *unused_cmp_data,
1528                               const void *entry, const void *entry_or_key,
1529                               const void *keydata)
1530 {
1531         const struct ref_store_hash_entry *e1 = entry, *e2 = entry_or_key;
1532         const char *name = keydata ? keydata : e2->name;
1533
1534         return strcmp(e1->name, name);
1535 }
1536
1537 static struct ref_store_hash_entry *alloc_ref_store_hash_entry(
1538                 const char *name, struct ref_store *refs)
1539 {
1540         struct ref_store_hash_entry *entry;
1541
1542         FLEX_ALLOC_STR(entry, name, name);
1543         hashmap_entry_init(entry, strhash(name));
1544         entry->refs = refs;
1545         return entry;
1546 }
1547
1548 /* A pointer to the ref_store for the main repository: */
1549 static struct ref_store *main_ref_store;
1550
1551 /* A hashmap of ref_stores, stored by submodule name: */
1552 static struct hashmap submodule_ref_stores;
1553
1554 /* A hashmap of ref_stores, stored by worktree id: */
1555 static struct hashmap worktree_ref_stores;
1556
1557 /*
1558  * Look up a ref store by name. If that ref_store hasn't been
1559  * registered yet, return NULL.
1560  */
1561 static struct ref_store *lookup_ref_store_map(struct hashmap *map,
1562                                               const char *name)
1563 {
1564         struct ref_store_hash_entry *entry;
1565
1566         if (!map->tablesize)
1567                 /* It's initialized on demand in register_ref_store(). */
1568                 return NULL;
1569
1570         entry = hashmap_get_from_hash(map, strhash(name), name);
1571         return entry ? entry->refs : NULL;
1572 }
1573
1574 /*
1575  * Create, record, and return a ref_store instance for the specified
1576  * gitdir.
1577  */
1578 static struct ref_store *ref_store_init(const char *gitdir,
1579                                         unsigned int flags)
1580 {
1581         const char *be_name = "files";
1582         struct ref_storage_be *be = find_ref_storage_backend(be_name);
1583         struct ref_store *refs;
1584
1585         if (!be)
1586                 die("BUG: reference backend %s is unknown", be_name);
1587
1588         refs = be->init(gitdir, flags);
1589         return refs;
1590 }
1591
1592 struct ref_store *get_main_ref_store(void)
1593 {
1594         if (main_ref_store)
1595                 return main_ref_store;
1596
1597         main_ref_store = ref_store_init(get_git_dir(), REF_STORE_ALL_CAPS);
1598         return main_ref_store;
1599 }
1600
1601 /*
1602  * Associate a ref store with a name. It is a fatal error to call this
1603  * function twice for the same name.
1604  */
1605 static void register_ref_store_map(struct hashmap *map,
1606                                    const char *type,
1607                                    struct ref_store *refs,
1608                                    const char *name)
1609 {
1610         if (!map->tablesize)
1611                 hashmap_init(map, ref_store_hash_cmp, NULL, 0);
1612
1613         if (hashmap_put(map, alloc_ref_store_hash_entry(name, refs)))
1614                 die("BUG: %s ref_store '%s' initialized twice", type, name);
1615 }
1616
1617 struct ref_store *get_submodule_ref_store(const char *submodule)
1618 {
1619         struct strbuf submodule_sb = STRBUF_INIT;
1620         struct ref_store *refs;
1621         int ret;
1622
1623         if (!submodule || !*submodule) {
1624                 /*
1625                  * FIXME: This case is ideally not allowed. But that
1626                  * can't happen until we clean up all the callers.
1627                  */
1628                 return get_main_ref_store();
1629         }
1630
1631         refs = lookup_ref_store_map(&submodule_ref_stores, submodule);
1632         if (refs)
1633                 return refs;
1634
1635         strbuf_addstr(&submodule_sb, submodule);
1636         ret = is_nonbare_repository_dir(&submodule_sb);
1637         strbuf_release(&submodule_sb);
1638         if (!ret)
1639                 return NULL;
1640
1641         ret = submodule_to_gitdir(&submodule_sb, submodule);
1642         if (ret) {
1643                 strbuf_release(&submodule_sb);
1644                 return NULL;
1645         }
1646
1647         /* assume that add_submodule_odb() has been called */
1648         refs = ref_store_init(submodule_sb.buf,
1649                               REF_STORE_READ | REF_STORE_ODB);
1650         register_ref_store_map(&submodule_ref_stores, "submodule",
1651                                refs, submodule);
1652
1653         strbuf_release(&submodule_sb);
1654         return refs;
1655 }
1656
1657 struct ref_store *get_worktree_ref_store(const struct worktree *wt)
1658 {
1659         struct ref_store *refs;
1660         const char *id;
1661
1662         if (wt->is_current)
1663                 return get_main_ref_store();
1664
1665         id = wt->id ? wt->id : "/";
1666         refs = lookup_ref_store_map(&worktree_ref_stores, id);
1667         if (refs)
1668                 return refs;
1669
1670         if (wt->id)
1671                 refs = ref_store_init(git_common_path("worktrees/%s", wt->id),
1672                                       REF_STORE_ALL_CAPS);
1673         else
1674                 refs = ref_store_init(get_git_common_dir(),
1675                                       REF_STORE_ALL_CAPS);
1676
1677         if (refs)
1678                 register_ref_store_map(&worktree_ref_stores, "worktree",
1679                                        refs, id);
1680         return refs;
1681 }
1682
1683 void base_ref_store_init(struct ref_store *refs,
1684                          const struct ref_storage_be *be)
1685 {
1686         refs->be = be;
1687 }
1688
1689 /* backend functions */
1690 int refs_pack_refs(struct ref_store *refs, unsigned int flags)
1691 {
1692         return refs->be->pack_refs(refs, flags);
1693 }
1694
1695 int refs_peel_ref(struct ref_store *refs, const char *refname,
1696                   unsigned char *sha1)
1697 {
1698         return refs->be->peel_ref(refs, refname, sha1);
1699 }
1700
1701 int peel_ref(const char *refname, unsigned char *sha1)
1702 {
1703         return refs_peel_ref(get_main_ref_store(), refname, sha1);
1704 }
1705
1706 int refs_create_symref(struct ref_store *refs,
1707                        const char *ref_target,
1708                        const char *refs_heads_master,
1709                        const char *logmsg)
1710 {
1711         return refs->be->create_symref(refs, ref_target,
1712                                        refs_heads_master,
1713                                        logmsg);
1714 }
1715
1716 int create_symref(const char *ref_target, const char *refs_heads_master,
1717                   const char *logmsg)
1718 {
1719         return refs_create_symref(get_main_ref_store(), ref_target,
1720                                   refs_heads_master, logmsg);
1721 }
1722
1723 int ref_update_reject_duplicates(struct string_list *refnames,
1724                                  struct strbuf *err)
1725 {
1726         size_t i, n = refnames->nr;
1727
1728         assert(err);
1729
1730         for (i = 1; i < n; i++) {
1731                 int cmp = strcmp(refnames->items[i - 1].string,
1732                                  refnames->items[i].string);
1733
1734                 if (!cmp) {
1735                         strbuf_addf(err,
1736                                     "multiple updates for ref '%s' not allowed.",
1737                                     refnames->items[i].string);
1738                         return 1;
1739                 } else if (cmp > 0) {
1740                         die("BUG: ref_update_reject_duplicates() received unsorted list");
1741                 }
1742         }
1743         return 0;
1744 }
1745
1746 int ref_transaction_prepare(struct ref_transaction *transaction,
1747                             struct strbuf *err)
1748 {
1749         struct ref_store *refs = transaction->ref_store;
1750
1751         switch (transaction->state) {
1752         case REF_TRANSACTION_OPEN:
1753                 /* Good. */
1754                 break;
1755         case REF_TRANSACTION_PREPARED:
1756                 die("BUG: prepare called twice on reference transaction");
1757                 break;
1758         case REF_TRANSACTION_CLOSED:
1759                 die("BUG: prepare called on a closed reference transaction");
1760                 break;
1761         default:
1762                 die("BUG: unexpected reference transaction state");
1763                 break;
1764         }
1765
1766         if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
1767                 strbuf_addstr(err,
1768                               _("ref updates forbidden inside quarantine environment"));
1769                 return -1;
1770         }
1771
1772         return refs->be->transaction_prepare(refs, transaction, err);
1773 }
1774
1775 int ref_transaction_abort(struct ref_transaction *transaction,
1776                           struct strbuf *err)
1777 {
1778         struct ref_store *refs = transaction->ref_store;
1779         int ret = 0;
1780
1781         switch (transaction->state) {
1782         case REF_TRANSACTION_OPEN:
1783                 /* No need to abort explicitly. */
1784                 break;
1785         case REF_TRANSACTION_PREPARED:
1786                 ret = refs->be->transaction_abort(refs, transaction, err);
1787                 break;
1788         case REF_TRANSACTION_CLOSED:
1789                 die("BUG: abort called on a closed reference transaction");
1790                 break;
1791         default:
1792                 die("BUG: unexpected reference transaction state");
1793                 break;
1794         }
1795
1796         ref_transaction_free(transaction);
1797         return ret;
1798 }
1799
1800 int ref_transaction_commit(struct ref_transaction *transaction,
1801                            struct strbuf *err)
1802 {
1803         struct ref_store *refs = transaction->ref_store;
1804         int ret;
1805
1806         switch (transaction->state) {
1807         case REF_TRANSACTION_OPEN:
1808                 /* Need to prepare first. */
1809                 ret = ref_transaction_prepare(transaction, err);
1810                 if (ret)
1811                         return ret;
1812                 break;
1813         case REF_TRANSACTION_PREPARED:
1814                 /* Fall through to finish. */
1815                 break;
1816         case REF_TRANSACTION_CLOSED:
1817                 die("BUG: commit called on a closed reference transaction");
1818                 break;
1819         default:
1820                 die("BUG: unexpected reference transaction state");
1821                 break;
1822         }
1823
1824         return refs->be->transaction_finish(refs, transaction, err);
1825 }
1826
1827 int refs_verify_refname_available(struct ref_store *refs,
1828                                   const char *refname,
1829                                   const struct string_list *extras,
1830                                   const struct string_list *skip,
1831                                   struct strbuf *err)
1832 {
1833         const char *slash;
1834         const char *extra_refname;
1835         struct strbuf dirname = STRBUF_INIT;
1836         struct strbuf referent = STRBUF_INIT;
1837         struct object_id oid;
1838         unsigned int type;
1839         struct ref_iterator *iter;
1840         int ok;
1841         int ret = -1;
1842
1843         /*
1844          * For the sake of comments in this function, suppose that
1845          * refname is "refs/foo/bar".
1846          */
1847
1848         assert(err);
1849
1850         strbuf_grow(&dirname, strlen(refname) + 1);
1851         for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
1852                 /* Expand dirname to the new prefix, not including the trailing slash: */
1853                 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
1854
1855                 /*
1856                  * We are still at a leading dir of the refname (e.g.,
1857                  * "refs/foo"; if there is a reference with that name,
1858                  * it is a conflict, *unless* it is in skip.
1859                  */
1860                 if (skip && string_list_has_string(skip, dirname.buf))
1861                         continue;
1862
1863                 if (!refs_read_raw_ref(refs, dirname.buf, oid.hash, &referent, &type)) {
1864                         strbuf_addf(err, "'%s' exists; cannot create '%s'",
1865                                     dirname.buf, refname);
1866                         goto cleanup;
1867                 }
1868
1869                 if (extras && string_list_has_string(extras, dirname.buf)) {
1870                         strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1871                                     refname, dirname.buf);
1872                         goto cleanup;
1873                 }
1874         }
1875
1876         /*
1877          * We are at the leaf of our refname (e.g., "refs/foo/bar").
1878          * There is no point in searching for a reference with that
1879          * name, because a refname isn't considered to conflict with
1880          * itself. But we still need to check for references whose
1881          * names are in the "refs/foo/bar/" namespace, because they
1882          * *do* conflict.
1883          */
1884         strbuf_addstr(&dirname, refname + dirname.len);
1885         strbuf_addch(&dirname, '/');
1886
1887         iter = refs_ref_iterator_begin(refs, dirname.buf, 0,
1888                                        DO_FOR_EACH_INCLUDE_BROKEN);
1889         while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
1890                 if (skip &&
1891                     string_list_has_string(skip, iter->refname))
1892                         continue;
1893
1894                 strbuf_addf(err, "'%s' exists; cannot create '%s'",
1895                             iter->refname, refname);
1896                 ref_iterator_abort(iter);
1897                 goto cleanup;
1898         }
1899
1900         if (ok != ITER_DONE)
1901                 die("BUG: error while iterating over references");
1902
1903         extra_refname = find_descendant_ref(dirname.buf, extras, skip);
1904         if (extra_refname)
1905                 strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1906                             refname, extra_refname);
1907         else
1908                 ret = 0;
1909
1910 cleanup:
1911         strbuf_release(&referent);
1912         strbuf_release(&dirname);
1913         return ret;
1914 }
1915
1916 int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1917 {
1918         struct ref_iterator *iter;
1919
1920         iter = refs->be->reflog_iterator_begin(refs);
1921
1922         return do_for_each_ref_iterator(iter, fn, cb_data);
1923 }
1924
1925 int for_each_reflog(each_ref_fn fn, void *cb_data)
1926 {
1927         return refs_for_each_reflog(get_main_ref_store(), fn, cb_data);
1928 }
1929
1930 int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
1931                                      const char *refname,
1932                                      each_reflog_ent_fn fn,
1933                                      void *cb_data)
1934 {
1935         return refs->be->for_each_reflog_ent_reverse(refs, refname,
1936                                                      fn, cb_data);
1937 }
1938
1939 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
1940                                 void *cb_data)
1941 {
1942         return refs_for_each_reflog_ent_reverse(get_main_ref_store(),
1943                                                 refname, fn, cb_data);
1944 }
1945
1946 int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
1947                              each_reflog_ent_fn fn, void *cb_data)
1948 {
1949         return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
1950 }
1951
1952 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
1953                         void *cb_data)
1954 {
1955         return refs_for_each_reflog_ent(get_main_ref_store(), refname,
1956                                         fn, cb_data);
1957 }
1958
1959 int refs_reflog_exists(struct ref_store *refs, const char *refname)
1960 {
1961         return refs->be->reflog_exists(refs, refname);
1962 }
1963
1964 int reflog_exists(const char *refname)
1965 {
1966         return refs_reflog_exists(get_main_ref_store(), refname);
1967 }
1968
1969 int refs_create_reflog(struct ref_store *refs, const char *refname,
1970                        int force_create, struct strbuf *err)
1971 {
1972         return refs->be->create_reflog(refs, refname, force_create, err);
1973 }
1974
1975 int safe_create_reflog(const char *refname, int force_create,
1976                        struct strbuf *err)
1977 {
1978         return refs_create_reflog(get_main_ref_store(), refname,
1979                                   force_create, err);
1980 }
1981
1982 int refs_delete_reflog(struct ref_store *refs, const char *refname)
1983 {
1984         return refs->be->delete_reflog(refs, refname);
1985 }
1986
1987 int delete_reflog(const char *refname)
1988 {
1989         return refs_delete_reflog(get_main_ref_store(), refname);
1990 }
1991
1992 int refs_reflog_expire(struct ref_store *refs,
1993                        const char *refname, const unsigned char *sha1,
1994                        unsigned int flags,
1995                        reflog_expiry_prepare_fn prepare_fn,
1996                        reflog_expiry_should_prune_fn should_prune_fn,
1997                        reflog_expiry_cleanup_fn cleanup_fn,
1998                        void *policy_cb_data)
1999 {
2000         return refs->be->reflog_expire(refs, refname, sha1, flags,
2001                                        prepare_fn, should_prune_fn,
2002                                        cleanup_fn, policy_cb_data);
2003 }
2004
2005 int reflog_expire(const char *refname, const unsigned char *sha1,
2006                   unsigned int flags,
2007                   reflog_expiry_prepare_fn prepare_fn,
2008                   reflog_expiry_should_prune_fn should_prune_fn,
2009                   reflog_expiry_cleanup_fn cleanup_fn,
2010                   void *policy_cb_data)
2011 {
2012         return refs_reflog_expire(get_main_ref_store(),
2013                                   refname, sha1, flags,
2014                                   prepare_fn, should_prune_fn,
2015                                   cleanup_fn, policy_cb_data);
2016 }
2017
2018 int initial_ref_transaction_commit(struct ref_transaction *transaction,
2019                                    struct strbuf *err)
2020 {
2021         struct ref_store *refs = transaction->ref_store;
2022
2023         return refs->be->initial_transaction_commit(refs, transaction, err);
2024 }
2025
2026 int refs_delete_refs(struct ref_store *refs, const char *msg,
2027                      struct string_list *refnames, unsigned int flags)
2028 {
2029         return refs->be->delete_refs(refs, msg, refnames, flags);
2030 }
2031
2032 int delete_refs(const char *msg, struct string_list *refnames,
2033                 unsigned int flags)
2034 {
2035         return refs_delete_refs(get_main_ref_store(), msg, refnames, flags);
2036 }
2037
2038 int refs_rename_ref(struct ref_store *refs, const char *oldref,
2039                     const char *newref, const char *logmsg)
2040 {
2041         return refs->be->rename_ref(refs, oldref, newref, logmsg);
2042 }
2043
2044 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
2045 {
2046         return refs_rename_ref(get_main_ref_store(), oldref, newref, logmsg);
2047 }