refs.con commit Merge branch 'jk/url-insteadof-config' (ec8455e)
   1/*
   2 * The backend-independent part of the reference module.
   3 */
   4
   5#include "cache.h"
   6#include "hashmap.h"
   7#include "lockfile.h"
   8#include "iterator.h"
   9#include "refs.h"
  10#include "refs/refs-internal.h"
  11#include "object.h"
  12#include "tag.h"
  13#include "submodule.h"
  14#include "worktree.h"
  15
  16/*
  17 * List of all available backends
  18 */
  19static struct ref_storage_be *refs_backends = &refs_be_files;
  20
  21static struct ref_storage_be *find_ref_storage_backend(const char *name)
  22{
  23        struct ref_storage_be *be;
  24        for (be = refs_backends; be; be = be->next)
  25                if (!strcmp(be->name, name))
  26                        return be;
  27        return NULL;
  28}
  29
  30int ref_storage_backend_exists(const char *name)
  31{
  32        return find_ref_storage_backend(name) != NULL;
  33}
  34
  35/*
  36 * How to handle various characters in refnames:
  37 * 0: An acceptable character for refs
  38 * 1: End-of-component
  39 * 2: ., look for a preceding . to reject .. in refs
  40 * 3: {, look for a preceding @ to reject @{ in refs
  41 * 4: A bad character: ASCII control characters, and
  42 *    ":", "?", "[", "\", "^", "~", SP, or TAB
  43 * 5: *, reject unless REFNAME_REFSPEC_PATTERN is set
  44 */
  45static unsigned char refname_disposition[256] = {
  46        1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
  47        4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
  48        4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 1,
  49        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
  50        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  51        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
  52        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  53        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
  54};
  55
  56/*
  57 * Try to read one refname component from the front of refname.
  58 * Return the length of the component found, or -1 if the component is
  59 * not legal.  It is legal if it is something reasonable to have under
  60 * ".git/refs/"; We do not like it if:
  61 *
  62 * - any path component of it begins with ".", or
  63 * - it has double dots "..", or
  64 * - it has ASCII control characters, or
  65 * - it has ":", "?", "[", "\", "^", "~", SP, or TAB anywhere, or
  66 * - it has "*" anywhere unless REFNAME_REFSPEC_PATTERN is set, or
  67 * - it ends with a "/", or
  68 * - it ends with ".lock", or
  69 * - it contains a "@{" portion
  70 */
  71static int check_refname_component(const char *refname, int *flags)
  72{
  73        const char *cp;
  74        char last = '\0';
  75
  76        for (cp = refname; ; cp++) {
  77                int ch = *cp & 255;
  78                unsigned char disp = refname_disposition[ch];
  79                switch (disp) {
  80                case 1:
  81                        goto out;
  82                case 2:
  83                        if (last == '.')
  84                                return -1; /* Refname contains "..". */
  85                        break;
  86                case 3:
  87                        if (last == '@')
  88                                return -1; /* Refname contains "@{". */
  89                        break;
  90                case 4:
  91                        return -1;
  92                case 5:
  93                        if (!(*flags & REFNAME_REFSPEC_PATTERN))
  94                                return -1; /* refspec can't be a pattern */
  95
  96                        /*
  97                         * Unset the pattern flag so that we only accept
  98                         * a single asterisk for one side of refspec.
  99                         */
 100                        *flags &= ~ REFNAME_REFSPEC_PATTERN;
 101                        break;
 102                }
 103                last = ch;
 104        }
 105out:
 106        if (cp == refname)
 107                return 0; /* Component has zero length. */
 108        if (refname[0] == '.')
 109                return -1; /* Component starts with '.'. */
 110        if (cp - refname >= LOCK_SUFFIX_LEN &&
 111            !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
 112                return -1; /* Refname ends with ".lock". */
 113        return cp - refname;
 114}
 115
 116int check_refname_format(const char *refname, int flags)
 117{
 118        int component_len, component_count = 0;
 119
 120        if (!strcmp(refname, "@"))
 121                /* Refname is a single character '@'. */
 122                return -1;
 123
 124        while (1) {
 125                /* We are at the start of a path component. */
 126                component_len = check_refname_component(refname, &flags);
 127                if (component_len <= 0)
 128                        return -1;
 129
 130                component_count++;
 131                if (refname[component_len] == '\0')
 132                        break;
 133                /* Skip to next component. */
 134                refname += component_len + 1;
 135        }
 136
 137        if (refname[component_len - 1] == '.')
 138                return -1; /* Refname ends with '.'. */
 139        if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
 140                return -1; /* Refname has only one component. */
 141        return 0;
 142}
 143
 144int refname_is_safe(const char *refname)
 145{
 146        const char *rest;
 147
 148        if (skip_prefix(refname, "refs/", &rest)) {
 149                char *buf;
 150                int result;
 151                size_t restlen = strlen(rest);
 152
 153                /* rest must not be empty, or start or end with "/" */
 154                if (!restlen || *rest == '/' || rest[restlen - 1] == '/')
 155                        return 0;
 156
 157                /*
 158                 * Does the refname try to escape refs/?
 159                 * For example: refs/foo/../bar is safe but refs/foo/../../bar
 160                 * is not.
 161                 */
 162                buf = xmallocz(restlen);
 163                result = !normalize_path_copy(buf, rest) && !strcmp(buf, rest);
 164                free(buf);
 165                return result;
 166        }
 167
 168        do {
 169                if (!isupper(*refname) && *refname != '_')
 170                        return 0;
 171                refname++;
 172        } while (*refname);
 173        return 1;
 174}
 175
 176char *refs_resolve_refdup(struct ref_store *refs,
 177                          const char *refname, int resolve_flags,
 178                          unsigned char *sha1, int *flags)
 179{
 180        const char *result;
 181
 182        result = refs_resolve_ref_unsafe(refs, refname, resolve_flags,
 183                                         sha1, flags);
 184        return xstrdup_or_null(result);
 185}
 186
 187char *resolve_refdup(const char *refname, int resolve_flags,
 188                     unsigned char *sha1, int *flags)
 189{
 190        return refs_resolve_refdup(get_main_ref_store(),
 191                                   refname, resolve_flags,
 192                                   sha1, flags);
 193}
 194
 195/* The argument to filter_refs */
 196struct ref_filter {
 197        const char *pattern;
 198        each_ref_fn *fn;
 199        void *cb_data;
 200};
 201
 202int refs_read_ref_full(struct ref_store *refs, const char *refname,
 203                       int resolve_flags, unsigned char *sha1, int *flags)
 204{
 205        if (refs_resolve_ref_unsafe(refs, refname, resolve_flags, sha1, flags))
 206                return 0;
 207        return -1;
 208}
 209
 210int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
 211{
 212        return refs_read_ref_full(get_main_ref_store(), refname,
 213                                  resolve_flags, sha1, flags);
 214}
 215
 216int read_ref(const char *refname, unsigned char *sha1)
 217{
 218        return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
 219}
 220
 221int ref_exists(const char *refname)
 222{
 223        unsigned char sha1[20];
 224        return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
 225}
 226
 227static int filter_refs(const char *refname, const struct object_id *oid,
 228                           int flags, void *data)
 229{
 230        struct ref_filter *filter = (struct ref_filter *)data;
 231
 232        if (wildmatch(filter->pattern, refname, 0, NULL))
 233                return 0;
 234        return filter->fn(refname, oid, flags, filter->cb_data);
 235}
 236
 237enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
 238{
 239        struct object *o = lookup_unknown_object(name);
 240
 241        if (o->type == OBJ_NONE) {
 242                int type = sha1_object_info(name, NULL);
 243                if (type < 0 || !object_as_type(o, type, 0))
 244                        return PEEL_INVALID;
 245        }
 246
 247        if (o->type != OBJ_TAG)
 248                return PEEL_NON_TAG;
 249
 250        o = deref_tag_noverify(o);
 251        if (!o)
 252                return PEEL_INVALID;
 253
 254        hashcpy(sha1, o->oid.hash);
 255        return PEEL_PEELED;
 256}
 257
 258struct warn_if_dangling_data {
 259        FILE *fp;
 260        const char *refname;
 261        const struct string_list *refnames;
 262        const char *msg_fmt;
 263};
 264
 265static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
 266                                   int flags, void *cb_data)
 267{
 268        struct warn_if_dangling_data *d = cb_data;
 269        const char *resolves_to;
 270        struct object_id junk;
 271
 272        if (!(flags & REF_ISSYMREF))
 273                return 0;
 274
 275        resolves_to = resolve_ref_unsafe(refname, 0, junk.hash, NULL);
 276        if (!resolves_to
 277            || (d->refname
 278                ? strcmp(resolves_to, d->refname)
 279                : !string_list_has_string(d->refnames, resolves_to))) {
 280                return 0;
 281        }
 282
 283        fprintf(d->fp, d->msg_fmt, refname);
 284        fputc('\n', d->fp);
 285        return 0;
 286}
 287
 288void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 289{
 290        struct warn_if_dangling_data data;
 291
 292        data.fp = fp;
 293        data.refname = refname;
 294        data.refnames = NULL;
 295        data.msg_fmt = msg_fmt;
 296        for_each_rawref(warn_if_dangling_symref, &data);
 297}
 298
 299void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
 300{
 301        struct warn_if_dangling_data data;
 302
 303        data.fp = fp;
 304        data.refname = NULL;
 305        data.refnames = refnames;
 306        data.msg_fmt = msg_fmt;
 307        for_each_rawref(warn_if_dangling_symref, &data);
 308}
 309
 310int refs_for_each_tag_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 311{
 312        return refs_for_each_ref_in(refs, "refs/tags/", fn, cb_data);
 313}
 314
 315int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 316{
 317        return refs_for_each_tag_ref(get_main_ref_store(), fn, cb_data);
 318}
 319
 320int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 321{
 322        return refs_for_each_tag_ref(get_submodule_ref_store(submodule),
 323                                     fn, cb_data);
 324}
 325
 326int refs_for_each_branch_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 327{
 328        return refs_for_each_ref_in(refs, "refs/heads/", fn, cb_data);
 329}
 330
 331int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 332{
 333        return refs_for_each_branch_ref(get_main_ref_store(), fn, cb_data);
 334}
 335
 336int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 337{
 338        return refs_for_each_branch_ref(get_submodule_ref_store(submodule),
 339                                        fn, cb_data);
 340}
 341
 342int refs_for_each_remote_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 343{
 344        return refs_for_each_ref_in(refs, "refs/remotes/", fn, cb_data);
 345}
 346
 347int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 348{
 349        return refs_for_each_remote_ref(get_main_ref_store(), fn, cb_data);
 350}
 351
 352int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 353{
 354        return refs_for_each_remote_ref(get_submodule_ref_store(submodule),
 355                                        fn, cb_data);
 356}
 357
 358int head_ref_namespaced(each_ref_fn fn, void *cb_data)
 359{
 360        struct strbuf buf = STRBUF_INIT;
 361        int ret = 0;
 362        struct object_id oid;
 363        int flag;
 364
 365        strbuf_addf(&buf, "%sHEAD", get_git_namespace());
 366        if (!read_ref_full(buf.buf, RESOLVE_REF_READING, oid.hash, &flag))
 367                ret = fn(buf.buf, &oid, flag, cb_data);
 368        strbuf_release(&buf);
 369
 370        return ret;
 371}
 372
 373int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 374        const char *prefix, void *cb_data)
 375{
 376        struct strbuf real_pattern = STRBUF_INIT;
 377        struct ref_filter filter;
 378        int ret;
 379
 380        if (!prefix && !starts_with(pattern, "refs/"))
 381                strbuf_addstr(&real_pattern, "refs/");
 382        else if (prefix)
 383                strbuf_addstr(&real_pattern, prefix);
 384        strbuf_addstr(&real_pattern, pattern);
 385
 386        if (!has_glob_specials(pattern)) {
 387                /* Append implied '/' '*' if not present. */
 388                strbuf_complete(&real_pattern, '/');
 389                /* No need to check for '*', there is none. */
 390                strbuf_addch(&real_pattern, '*');
 391        }
 392
 393        filter.pattern = real_pattern.buf;
 394        filter.fn = fn;
 395        filter.cb_data = cb_data;
 396        ret = for_each_ref(filter_refs, &filter);
 397
 398        strbuf_release(&real_pattern);
 399        return ret;
 400}
 401
 402int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
 403{
 404        return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
 405}
 406
 407const char *prettify_refname(const char *name)
 408{
 409        if (skip_prefix(name, "refs/heads/", &name) ||
 410            skip_prefix(name, "refs/tags/", &name) ||
 411            skip_prefix(name, "refs/remotes/", &name))
 412                ; /* nothing */
 413        return name;
 414}
 415
 416static const char *ref_rev_parse_rules[] = {
 417        "%.*s",
 418        "refs/%.*s",
 419        "refs/tags/%.*s",
 420        "refs/heads/%.*s",
 421        "refs/remotes/%.*s",
 422        "refs/remotes/%.*s/HEAD",
 423        NULL
 424};
 425
 426int refname_match(const char *abbrev_name, const char *full_name)
 427{
 428        const char **p;
 429        const int abbrev_name_len = strlen(abbrev_name);
 430
 431        for (p = ref_rev_parse_rules; *p; p++) {
 432                if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
 433                        return 1;
 434                }
 435        }
 436
 437        return 0;
 438}
 439
 440/*
 441 * *string and *len will only be substituted, and *string returned (for
 442 * later free()ing) if the string passed in is a magic short-hand form
 443 * to name a branch.
 444 */
 445static char *substitute_branch_name(const char **string, int *len)
 446{
 447        struct strbuf buf = STRBUF_INIT;
 448        int ret = interpret_branch_name(*string, *len, &buf, 0);
 449
 450        if (ret == *len) {
 451                size_t size;
 452                *string = strbuf_detach(&buf, &size);
 453                *len = size;
 454                return (char *)*string;
 455        }
 456
 457        return NULL;
 458}
 459
 460int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 461{
 462        char *last_branch = substitute_branch_name(&str, &len);
 463        int   refs_found  = expand_ref(str, len, sha1, ref);
 464        free(last_branch);
 465        return refs_found;
 466}
 467
 468int expand_ref(const char *str, int len, unsigned char *sha1, char **ref)
 469{
 470        const char **p, *r;
 471        int refs_found = 0;
 472        struct strbuf fullref = STRBUF_INIT;
 473
 474        *ref = NULL;
 475        for (p = ref_rev_parse_rules; *p; p++) {
 476                unsigned char sha1_from_ref[20];
 477                unsigned char *this_result;
 478                int flag;
 479
 480                this_result = refs_found ? sha1_from_ref : sha1;
 481                strbuf_reset(&fullref);
 482                strbuf_addf(&fullref, *p, len, str);
 483                r = resolve_ref_unsafe(fullref.buf, RESOLVE_REF_READING,
 484                                       this_result, &flag);
 485                if (r) {
 486                        if (!refs_found++)
 487                                *ref = xstrdup(r);
 488                        if (!warn_ambiguous_refs)
 489                                break;
 490                } else if ((flag & REF_ISSYMREF) && strcmp(fullref.buf, "HEAD")) {
 491                        warning("ignoring dangling symref %s.", fullref.buf);
 492                } else if ((flag & REF_ISBROKEN) && strchr(fullref.buf, '/')) {
 493                        warning("ignoring broken ref %s.", fullref.buf);
 494                }
 495        }
 496        strbuf_release(&fullref);
 497        return refs_found;
 498}
 499
 500int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 501{
 502        char *last_branch = substitute_branch_name(&str, &len);
 503        const char **p;
 504        int logs_found = 0;
 505        struct strbuf path = STRBUF_INIT;
 506
 507        *log = NULL;
 508        for (p = ref_rev_parse_rules; *p; p++) {
 509                unsigned char hash[20];
 510                const char *ref, *it;
 511
 512                strbuf_reset(&path);
 513                strbuf_addf(&path, *p, len, str);
 514                ref = resolve_ref_unsafe(path.buf, RESOLVE_REF_READING,
 515                                         hash, NULL);
 516                if (!ref)
 517                        continue;
 518                if (reflog_exists(path.buf))
 519                        it = path.buf;
 520                else if (strcmp(ref, path.buf) && reflog_exists(ref))
 521                        it = ref;
 522                else
 523                        continue;
 524                if (!logs_found++) {
 525                        *log = xstrdup(it);
 526                        hashcpy(sha1, hash);
 527                }
 528                if (!warn_ambiguous_refs)
 529                        break;
 530        }
 531        strbuf_release(&path);
 532        free(last_branch);
 533        return logs_found;
 534}
 535
 536static int is_per_worktree_ref(const char *refname)
 537{
 538        return !strcmp(refname, "HEAD") ||
 539                starts_with(refname, "refs/bisect/");
 540}
 541
 542static int is_pseudoref_syntax(const char *refname)
 543{
 544        const char *c;
 545
 546        for (c = refname; *c; c++) {
 547                if (!isupper(*c) && *c != '-' && *c != '_')
 548                        return 0;
 549        }
 550
 551        return 1;
 552}
 553
 554enum ref_type ref_type(const char *refname)
 555{
 556        if (is_per_worktree_ref(refname))
 557                return REF_TYPE_PER_WORKTREE;
 558        if (is_pseudoref_syntax(refname))
 559                return REF_TYPE_PSEUDOREF;
 560       return REF_TYPE_NORMAL;
 561}
 562
 563static int write_pseudoref(const char *pseudoref, const unsigned char *sha1,
 564                           const unsigned char *old_sha1, struct strbuf *err)
 565{
 566        const char *filename;
 567        int fd;
 568        static struct lock_file lock;
 569        struct strbuf buf = STRBUF_INIT;
 570        int ret = -1;
 571
 572        strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
 573
 574        filename = git_path("%s", pseudoref);
 575        fd = hold_lock_file_for_update(&lock, filename, LOCK_DIE_ON_ERROR);
 576        if (fd < 0) {
 577                strbuf_addf(err, "could not open '%s' for writing: %s",
 578                            filename, strerror(errno));
 579                return -1;
 580        }
 581
 582        if (old_sha1) {
 583                unsigned char actual_old_sha1[20];
 584
 585                if (read_ref(pseudoref, actual_old_sha1))
 586                        die("could not read ref '%s'", pseudoref);
 587                if (hashcmp(actual_old_sha1, old_sha1)) {
 588                        strbuf_addf(err, "unexpected sha1 when writing '%s'", pseudoref);
 589                        rollback_lock_file(&lock);
 590                        goto done;
 591                }
 592        }
 593
 594        if (write_in_full(fd, buf.buf, buf.len) != buf.len) {
 595                strbuf_addf(err, "could not write to '%s'", filename);
 596                rollback_lock_file(&lock);
 597                goto done;
 598        }
 599
 600        commit_lock_file(&lock);
 601        ret = 0;
 602done:
 603        strbuf_release(&buf);
 604        return ret;
 605}
 606
 607static int delete_pseudoref(const char *pseudoref, const unsigned char *old_sha1)
 608{
 609        static struct lock_file lock;
 610        const char *filename;
 611
 612        filename = git_path("%s", pseudoref);
 613
 614        if (old_sha1 && !is_null_sha1(old_sha1)) {
 615                int fd;
 616                unsigned char actual_old_sha1[20];
 617
 618                fd = hold_lock_file_for_update(&lock, filename,
 619                                               LOCK_DIE_ON_ERROR);
 620                if (fd < 0)
 621                        die_errno(_("Could not open '%s' for writing"), filename);
 622                if (read_ref(pseudoref, actual_old_sha1))
 623                        die("could not read ref '%s'", pseudoref);
 624                if (hashcmp(actual_old_sha1, old_sha1)) {
 625                        warning("Unexpected sha1 when deleting %s", pseudoref);
 626                        rollback_lock_file(&lock);
 627                        return -1;
 628                }
 629
 630                unlink(filename);
 631                rollback_lock_file(&lock);
 632        } else {
 633                unlink(filename);
 634        }
 635
 636        return 0;
 637}
 638
 639int refs_delete_ref(struct ref_store *refs, const char *msg,
 640                    const char *refname,
 641                    const unsigned char *old_sha1,
 642                    unsigned int flags)
 643{
 644        struct ref_transaction *transaction;
 645        struct strbuf err = STRBUF_INIT;
 646
 647        if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
 648                assert(refs == get_main_ref_store());
 649                return delete_pseudoref(refname, old_sha1);
 650        }
 651
 652        transaction = ref_store_transaction_begin(refs, &err);
 653        if (!transaction ||
 654            ref_transaction_delete(transaction, refname, old_sha1,
 655                                   flags, msg, &err) ||
 656            ref_transaction_commit(transaction, &err)) {
 657                error("%s", err.buf);
 658                ref_transaction_free(transaction);
 659                strbuf_release(&err);
 660                return 1;
 661        }
 662        ref_transaction_free(transaction);
 663        strbuf_release(&err);
 664        return 0;
 665}
 666
 667int delete_ref(const char *msg, const char *refname,
 668               const unsigned char *old_sha1, unsigned int flags)
 669{
 670        return refs_delete_ref(get_main_ref_store(), msg, refname,
 671                               old_sha1, flags);
 672}
 673
 674int copy_reflog_msg(char *buf, const char *msg)
 675{
 676        char *cp = buf;
 677        char c;
 678        int wasspace = 1;
 679
 680        *cp++ = '\t';
 681        while ((c = *msg++)) {
 682                if (wasspace && isspace(c))
 683                        continue;
 684                wasspace = isspace(c);
 685                if (wasspace)
 686                        c = ' ';
 687                *cp++ = c;
 688        }
 689        while (buf < cp && isspace(cp[-1]))
 690                cp--;
 691        *cp++ = '\n';
 692        return cp - buf;
 693}
 694
 695int should_autocreate_reflog(const char *refname)
 696{
 697        switch (log_all_ref_updates) {
 698        case LOG_REFS_ALWAYS:
 699                return 1;
 700        case LOG_REFS_NORMAL:
 701                return starts_with(refname, "refs/heads/") ||
 702                        starts_with(refname, "refs/remotes/") ||
 703                        starts_with(refname, "refs/notes/") ||
 704                        !strcmp(refname, "HEAD");
 705        default:
 706                return 0;
 707        }
 708}
 709
 710int is_branch(const char *refname)
 711{
 712        return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
 713}
 714
 715struct read_ref_at_cb {
 716        const char *refname;
 717        timestamp_t at_time;
 718        int cnt;
 719        int reccnt;
 720        unsigned char *sha1;
 721        int found_it;
 722
 723        unsigned char osha1[20];
 724        unsigned char nsha1[20];
 725        int tz;
 726        timestamp_t date;
 727        char **msg;
 728        timestamp_t *cutoff_time;
 729        int *cutoff_tz;
 730        int *cutoff_cnt;
 731};
 732
 733static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
 734                const char *email, timestamp_t timestamp, int tz,
 735                const char *message, void *cb_data)
 736{
 737        struct read_ref_at_cb *cb = cb_data;
 738
 739        cb->reccnt++;
 740        cb->tz = tz;
 741        cb->date = timestamp;
 742
 743        if (timestamp <= cb->at_time || cb->cnt == 0) {
 744                if (cb->msg)
 745                        *cb->msg = xstrdup(message);
 746                if (cb->cutoff_time)
 747                        *cb->cutoff_time = timestamp;
 748                if (cb->cutoff_tz)
 749                        *cb->cutoff_tz = tz;
 750                if (cb->cutoff_cnt)
 751                        *cb->cutoff_cnt = cb->reccnt - 1;
 752                /*
 753                 * we have not yet updated cb->[n|o]sha1 so they still
 754                 * hold the values for the previous record.
 755                 */
 756                if (!is_null_sha1(cb->osha1)) {
 757                        hashcpy(cb->sha1, noid->hash);
 758                        if (hashcmp(cb->osha1, noid->hash))
 759                                warning("Log for ref %s has gap after %s.",
 760                                        cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
 761                }
 762                else if (cb->date == cb->at_time)
 763                        hashcpy(cb->sha1, noid->hash);
 764                else if (hashcmp(noid->hash, cb->sha1))
 765                        warning("Log for ref %s unexpectedly ended on %s.",
 766                                cb->refname, show_date(cb->date, cb->tz,
 767                                                       DATE_MODE(RFC2822)));
 768                hashcpy(cb->osha1, ooid->hash);
 769                hashcpy(cb->nsha1, noid->hash);
 770                cb->found_it = 1;
 771                return 1;
 772        }
 773        hashcpy(cb->osha1, ooid->hash);
 774        hashcpy(cb->nsha1, noid->hash);
 775        if (cb->cnt > 0)
 776                cb->cnt--;
 777        return 0;
 778}
 779
 780static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
 781                                  const char *email, timestamp_t timestamp,
 782                                  int tz, const char *message, void *cb_data)
 783{
 784        struct read_ref_at_cb *cb = cb_data;
 785
 786        if (cb->msg)
 787                *cb->msg = xstrdup(message);
 788        if (cb->cutoff_time)
 789                *cb->cutoff_time = timestamp;
 790        if (cb->cutoff_tz)
 791                *cb->cutoff_tz = tz;
 792        if (cb->cutoff_cnt)
 793                *cb->cutoff_cnt = cb->reccnt;
 794        hashcpy(cb->sha1, ooid->hash);
 795        if (is_null_sha1(cb->sha1))
 796                hashcpy(cb->sha1, noid->hash);
 797        /* We just want the first entry */
 798        return 1;
 799}
 800
 801int read_ref_at(const char *refname, unsigned int flags, timestamp_t at_time, int cnt,
 802                unsigned char *sha1, char **msg,
 803                timestamp_t *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
 804{
 805        struct read_ref_at_cb cb;
 806
 807        memset(&cb, 0, sizeof(cb));
 808        cb.refname = refname;
 809        cb.at_time = at_time;
 810        cb.cnt = cnt;
 811        cb.msg = msg;
 812        cb.cutoff_time = cutoff_time;
 813        cb.cutoff_tz = cutoff_tz;
 814        cb.cutoff_cnt = cutoff_cnt;
 815        cb.sha1 = sha1;
 816
 817        for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
 818
 819        if (!cb.reccnt) {
 820                if (flags & GET_SHA1_QUIETLY)
 821                        exit(128);
 822                else
 823                        die("Log for %s is empty.", refname);
 824        }
 825        if (cb.found_it)
 826                return 0;
 827
 828        for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
 829
 830        return 1;
 831}
 832
 833struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
 834                                                    struct strbuf *err)
 835{
 836        struct ref_transaction *tr;
 837        assert(err);
 838
 839        tr = xcalloc(1, sizeof(struct ref_transaction));
 840        tr->ref_store = refs;
 841        return tr;
 842}
 843
 844struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 845{
 846        return ref_store_transaction_begin(get_main_ref_store(), err);
 847}
 848
 849void ref_transaction_free(struct ref_transaction *transaction)
 850{
 851        int i;
 852
 853        if (!transaction)
 854                return;
 855
 856        for (i = 0; i < transaction->nr; i++) {
 857                free(transaction->updates[i]->msg);
 858                free(transaction->updates[i]);
 859        }
 860        free(transaction->updates);
 861        free(transaction);
 862}
 863
 864struct ref_update *ref_transaction_add_update(
 865                struct ref_transaction *transaction,
 866                const char *refname, unsigned int flags,
 867                const unsigned char *new_sha1,
 868                const unsigned char *old_sha1,
 869                const char *msg)
 870{
 871        struct ref_update *update;
 872
 873        if (transaction->state != REF_TRANSACTION_OPEN)
 874                die("BUG: update called for transaction that is not open");
 875
 876        if ((flags & REF_ISPRUNING) && !(flags & REF_NODEREF))
 877                die("BUG: REF_ISPRUNING set without REF_NODEREF");
 878
 879        FLEX_ALLOC_STR(update, refname, refname);
 880        ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
 881        transaction->updates[transaction->nr++] = update;
 882
 883        update->flags = flags;
 884
 885        if (flags & REF_HAVE_NEW)
 886                hashcpy(update->new_oid.hash, new_sha1);
 887        if (flags & REF_HAVE_OLD)
 888                hashcpy(update->old_oid.hash, old_sha1);
 889        update->msg = xstrdup_or_null(msg);
 890        return update;
 891}
 892
 893int ref_transaction_update(struct ref_transaction *transaction,
 894                           const char *refname,
 895                           const unsigned char *new_sha1,
 896                           const unsigned char *old_sha1,
 897                           unsigned int flags, const char *msg,
 898                           struct strbuf *err)
 899{
 900        assert(err);
 901
 902        if ((new_sha1 && !is_null_sha1(new_sha1)) ?
 903            check_refname_format(refname, REFNAME_ALLOW_ONELEVEL) :
 904            !refname_is_safe(refname)) {
 905                strbuf_addf(err, "refusing to update ref with bad name '%s'",
 906                            refname);
 907                return -1;
 908        }
 909
 910        flags |= (new_sha1 ? REF_HAVE_NEW : 0) | (old_sha1 ? REF_HAVE_OLD : 0);
 911
 912        ref_transaction_add_update(transaction, refname, flags,
 913                                   new_sha1, old_sha1, msg);
 914        return 0;
 915}
 916
 917int ref_transaction_create(struct ref_transaction *transaction,
 918                           const char *refname,
 919                           const unsigned char *new_sha1,
 920                           unsigned int flags, const char *msg,
 921                           struct strbuf *err)
 922{
 923        if (!new_sha1 || is_null_sha1(new_sha1))
 924                die("BUG: create called without valid new_sha1");
 925        return ref_transaction_update(transaction, refname, new_sha1,
 926                                      null_sha1, flags, msg, err);
 927}
 928
 929int ref_transaction_delete(struct ref_transaction *transaction,
 930                           const char *refname,
 931                           const unsigned char *old_sha1,
 932                           unsigned int flags, const char *msg,
 933                           struct strbuf *err)
 934{
 935        if (old_sha1 && is_null_sha1(old_sha1))
 936                die("BUG: delete called with old_sha1 set to zeros");
 937        return ref_transaction_update(transaction, refname,
 938                                      null_sha1, old_sha1,
 939                                      flags, msg, err);
 940}
 941
 942int ref_transaction_verify(struct ref_transaction *transaction,
 943                           const char *refname,
 944                           const unsigned char *old_sha1,
 945                           unsigned int flags,
 946                           struct strbuf *err)
 947{
 948        if (!old_sha1)
 949                die("BUG: verify called with old_sha1 set to NULL");
 950        return ref_transaction_update(transaction, refname,
 951                                      NULL, old_sha1,
 952                                      flags, NULL, err);
 953}
 954
 955int update_ref_oid(const char *msg, const char *refname,
 956               const struct object_id *new_oid, const struct object_id *old_oid,
 957               unsigned int flags, enum action_on_err onerr)
 958{
 959        return update_ref(msg, refname, new_oid ? new_oid->hash : NULL,
 960                old_oid ? old_oid->hash : NULL, flags, onerr);
 961}
 962
 963int refs_update_ref(struct ref_store *refs, const char *msg,
 964                    const char *refname, const unsigned char *new_sha1,
 965                    const unsigned char *old_sha1, unsigned int flags,
 966                    enum action_on_err onerr)
 967{
 968        struct ref_transaction *t = NULL;
 969        struct strbuf err = STRBUF_INIT;
 970        int ret = 0;
 971
 972        if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
 973                assert(refs == get_main_ref_store());
 974                ret = write_pseudoref(refname, new_sha1, old_sha1, &err);
 975        } else {
 976                t = ref_store_transaction_begin(refs, &err);
 977                if (!t ||
 978                    ref_transaction_update(t, refname, new_sha1, old_sha1,
 979                                           flags, msg, &err) ||
 980                    ref_transaction_commit(t, &err)) {
 981                        ret = 1;
 982                        ref_transaction_free(t);
 983                }
 984        }
 985        if (ret) {
 986                const char *str = "update_ref failed for ref '%s': %s";
 987
 988                switch (onerr) {
 989                case UPDATE_REFS_MSG_ON_ERR:
 990                        error(str, refname, err.buf);
 991                        break;
 992                case UPDATE_REFS_DIE_ON_ERR:
 993                        die(str, refname, err.buf);
 994                        break;
 995                case UPDATE_REFS_QUIET_ON_ERR:
 996                        break;
 997                }
 998                strbuf_release(&err);
 999                return 1;
1000        }
1001        strbuf_release(&err);
1002        if (t)
1003                ref_transaction_free(t);
1004        return 0;
1005}
1006
1007int update_ref(const char *msg, const char *refname,
1008               const unsigned char *new_sha1,
1009               const unsigned char *old_sha1,
1010               unsigned int flags, enum action_on_err onerr)
1011{
1012        return refs_update_ref(get_main_ref_store(), msg, refname, new_sha1,
1013                               old_sha1, flags, onerr);
1014}
1015
1016char *shorten_unambiguous_ref(const char *refname, int strict)
1017{
1018        int i;
1019        static char **scanf_fmts;
1020        static int nr_rules;
1021        char *short_name;
1022        struct strbuf resolved_buf = STRBUF_INIT;
1023
1024        if (!nr_rules) {
1025                /*
1026                 * Pre-generate scanf formats from ref_rev_parse_rules[].
1027                 * Generate a format suitable for scanf from a
1028                 * ref_rev_parse_rules rule by interpolating "%s" at the
1029                 * location of the "%.*s".
1030                 */
1031                size_t total_len = 0;
1032                size_t offset = 0;
1033
1034                /* the rule list is NULL terminated, count them first */
1035                for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
1036                        /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
1037                        total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
1038
1039                scanf_fmts = xmalloc(st_add(st_mult(sizeof(char *), nr_rules), total_len));
1040
1041                offset = 0;
1042                for (i = 0; i < nr_rules; i++) {
1043                        assert(offset < total_len);
1044                        scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
1045                        offset += snprintf(scanf_fmts[i], total_len - offset,
1046                                           ref_rev_parse_rules[i], 2, "%s") + 1;
1047                }
1048        }
1049
1050        /* bail out if there are no rules */
1051        if (!nr_rules)
1052                return xstrdup(refname);
1053
1054        /* buffer for scanf result, at most refname must fit */
1055        short_name = xstrdup(refname);
1056
1057        /* skip first rule, it will always match */
1058        for (i = nr_rules - 1; i > 0 ; --i) {
1059                int j;
1060                int rules_to_fail = i;
1061                int short_name_len;
1062
1063                if (1 != sscanf(refname, scanf_fmts[i], short_name))
1064                        continue;
1065
1066                short_name_len = strlen(short_name);
1067
1068                /*
1069                 * in strict mode, all (except the matched one) rules
1070                 * must fail to resolve to a valid non-ambiguous ref
1071                 */
1072                if (strict)
1073                        rules_to_fail = nr_rules;
1074
1075                /*
1076                 * check if the short name resolves to a valid ref,
1077                 * but use only rules prior to the matched one
1078                 */
1079                for (j = 0; j < rules_to_fail; j++) {
1080                        const char *rule = ref_rev_parse_rules[j];
1081
1082                        /* skip matched rule */
1083                        if (i == j)
1084                                continue;
1085
1086                        /*
1087                         * the short name is ambiguous, if it resolves
1088                         * (with this previous rule) to a valid ref
1089                         * read_ref() returns 0 on success
1090                         */
1091                        strbuf_reset(&resolved_buf);
1092                        strbuf_addf(&resolved_buf, rule,
1093                                    short_name_len, short_name);
1094                        if (ref_exists(resolved_buf.buf))
1095                                break;
1096                }
1097
1098                /*
1099                 * short name is non-ambiguous if all previous rules
1100                 * haven't resolved to a valid ref
1101                 */
1102                if (j == rules_to_fail) {
1103                        strbuf_release(&resolved_buf);
1104                        return short_name;
1105                }
1106        }
1107
1108        strbuf_release(&resolved_buf);
1109        free(short_name);
1110        return xstrdup(refname);
1111}
1112
1113static struct string_list *hide_refs;
1114
1115int parse_hide_refs_config(const char *var, const char *value, const char *section)
1116{
1117        const char *key;
1118        if (!strcmp("transfer.hiderefs", var) ||
1119            (!parse_config_key(var, section, NULL, NULL, &key) &&
1120             !strcmp(key, "hiderefs"))) {
1121                char *ref;
1122                int len;
1123
1124                if (!value)
1125                        return config_error_nonbool(var);
1126                ref = xstrdup(value);
1127                len = strlen(ref);
1128                while (len && ref[len - 1] == '/')
1129                        ref[--len] = '\0';
1130                if (!hide_refs) {
1131                        hide_refs = xcalloc(1, sizeof(*hide_refs));
1132                        hide_refs->strdup_strings = 1;
1133                }
1134                string_list_append(hide_refs, ref);
1135        }
1136        return 0;
1137}
1138
1139int ref_is_hidden(const char *refname, const char *refname_full)
1140{
1141        int i;
1142
1143        if (!hide_refs)
1144                return 0;
1145        for (i = hide_refs->nr - 1; i >= 0; i--) {
1146                const char *match = hide_refs->items[i].string;
1147                const char *subject;
1148                int neg = 0;
1149                int len;
1150
1151                if (*match == '!') {
1152                        neg = 1;
1153                        match++;
1154                }
1155
1156                if (*match == '^') {
1157                        subject = refname_full;
1158                        match++;
1159                } else {
1160                        subject = refname;
1161                }
1162
1163                /* refname can be NULL when namespaces are used. */
1164                if (!subject || !starts_with(subject, match))
1165                        continue;
1166                len = strlen(match);
1167                if (!subject[len] || subject[len] == '/')
1168                        return !neg;
1169        }
1170        return 0;
1171}
1172
1173const char *find_descendant_ref(const char *dirname,
1174                                const struct string_list *extras,
1175                                const struct string_list *skip)
1176{
1177        int pos;
1178
1179        if (!extras)
1180                return NULL;
1181
1182        /*
1183         * Look at the place where dirname would be inserted into
1184         * extras. If there is an entry at that position that starts
1185         * with dirname (remember, dirname includes the trailing
1186         * slash) and is not in skip, then we have a conflict.
1187         */
1188        for (pos = string_list_find_insert_index(extras, dirname, 0);
1189             pos < extras->nr; pos++) {
1190                const char *extra_refname = extras->items[pos].string;
1191
1192                if (!starts_with(extra_refname, dirname))
1193                        break;
1194
1195                if (!skip || !string_list_has_string(skip, extra_refname))
1196                        return extra_refname;
1197        }
1198        return NULL;
1199}
1200
1201int refs_rename_ref_available(struct ref_store *refs,
1202                              const char *old_refname,
1203                              const char *new_refname)
1204{
1205        struct string_list skip = STRING_LIST_INIT_NODUP;
1206        struct strbuf err = STRBUF_INIT;
1207        int ok;
1208
1209        string_list_insert(&skip, old_refname);
1210        ok = !refs_verify_refname_available(refs, new_refname,
1211                                            NULL, &skip, &err);
1212        if (!ok)
1213                error("%s", err.buf);
1214
1215        string_list_clear(&skip, 0);
1216        strbuf_release(&err);
1217        return ok;
1218}
1219
1220int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1221{
1222        struct object_id oid;
1223        int flag;
1224
1225        if (submodule) {
1226                if (resolve_gitlink_ref(submodule, "HEAD", oid.hash) == 0)
1227                        return fn("HEAD", &oid, 0, cb_data);
1228
1229                return 0;
1230        }
1231
1232        if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag))
1233                return fn("HEAD", &oid, flag, cb_data);
1234
1235        return 0;
1236}
1237
1238int head_ref(each_ref_fn fn, void *cb_data)
1239{
1240        return head_ref_submodule(NULL, fn, cb_data);
1241}
1242
1243struct ref_iterator *refs_ref_iterator_begin(
1244                struct ref_store *refs,
1245                const char *prefix, int trim, int flags)
1246{
1247        struct ref_iterator *iter;
1248
1249        iter = refs->be->iterator_begin(refs, prefix, flags);
1250        iter = prefix_ref_iterator_begin(iter, prefix, trim);
1251
1252        return iter;
1253}
1254
1255/*
1256 * Call fn for each reference in the specified submodule for which the
1257 * refname begins with prefix. If trim is non-zero, then trim that
1258 * many characters off the beginning of each refname before passing
1259 * the refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to
1260 * include broken references in the iteration. If fn ever returns a
1261 * non-zero value, stop the iteration and return that value;
1262 * otherwise, return 0.
1263 */
1264static int do_for_each_ref(struct ref_store *refs, const char *prefix,
1265                           each_ref_fn fn, int trim, int flags, void *cb_data)
1266{
1267        struct ref_iterator *iter;
1268
1269        if (!refs)
1270                return 0;
1271
1272        iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1273
1274        return do_for_each_ref_iterator(iter, fn, cb_data);
1275}
1276
1277int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1278{
1279        return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
1280}
1281
1282int for_each_ref(each_ref_fn fn, void *cb_data)
1283{
1284        return refs_for_each_ref(get_main_ref_store(), fn, cb_data);
1285}
1286
1287int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1288{
1289        return refs_for_each_ref(get_submodule_ref_store(submodule), fn, cb_data);
1290}
1291
1292int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
1293                         each_ref_fn fn, void *cb_data)
1294{
1295        return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
1296}
1297
1298int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1299{
1300        return refs_for_each_ref_in(get_main_ref_store(), prefix, fn, cb_data);
1301}
1302
1303int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1304{
1305        unsigned int flag = 0;
1306
1307        if (broken)
1308                flag = DO_FOR_EACH_INCLUDE_BROKEN;
1309        return do_for_each_ref(get_main_ref_store(),
1310                               prefix, fn, 0, flag, cb_data);
1311}
1312
1313int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1314                              each_ref_fn fn, void *cb_data)
1315{
1316        return refs_for_each_ref_in(get_submodule_ref_store(submodule),
1317                                    prefix, fn, cb_data);
1318}
1319
1320int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1321{
1322        return do_for_each_ref(get_main_ref_store(),
1323                               git_replace_ref_base, fn,
1324                               strlen(git_replace_ref_base),
1325                               0, cb_data);
1326}
1327
1328int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1329{
1330        struct strbuf buf = STRBUF_INIT;
1331        int ret;
1332        strbuf_addf(&buf, "%srefs/", get_git_namespace());
1333        ret = do_for_each_ref(get_main_ref_store(),
1334                              buf.buf, fn, 0, 0, cb_data);
1335        strbuf_release(&buf);
1336        return ret;
1337}
1338
1339int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1340{
1341        return do_for_each_ref(refs, "", fn, 0,
1342                               DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1343}
1344
1345int for_each_rawref(each_ref_fn fn, void *cb_data)
1346{
1347        return refs_for_each_rawref(get_main_ref_store(), fn, cb_data);
1348}
1349
1350int refs_read_raw_ref(struct ref_store *ref_store,
1351                      const char *refname, unsigned char *sha1,
1352                      struct strbuf *referent, unsigned int *type)
1353{
1354        return ref_store->be->read_raw_ref(ref_store, refname, sha1, referent, type);
1355}
1356
1357/* This function needs to return a meaningful errno on failure */
1358const char *refs_resolve_ref_unsafe(struct ref_store *refs,
1359                                    const char *refname,
1360                                    int resolve_flags,
1361                                    unsigned char *sha1, int *flags)
1362{
1363        static struct strbuf sb_refname = STRBUF_INIT;
1364        int unused_flags;
1365        int symref_count;
1366
1367        if (!flags)
1368                flags = &unused_flags;
1369
1370        *flags = 0;
1371
1372        if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1373                if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1374                    !refname_is_safe(refname)) {
1375                        errno = EINVAL;
1376                        return NULL;
1377                }
1378
1379                /*
1380                 * dwim_ref() uses REF_ISBROKEN to distinguish between
1381                 * missing refs and refs that were present but invalid,
1382                 * to complain about the latter to stderr.
1383                 *
1384                 * We don't know whether the ref exists, so don't set
1385                 * REF_ISBROKEN yet.
1386                 */
1387                *flags |= REF_BAD_NAME;
1388        }
1389
1390        for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
1391                unsigned int read_flags = 0;
1392
1393                if (refs_read_raw_ref(refs, refname,
1394                                      sha1, &sb_refname, &read_flags)) {
1395                        *flags |= read_flags;
1396                        if (errno != ENOENT || (resolve_flags & RESOLVE_REF_READING))
1397                                return NULL;
1398                        hashclr(sha1);
1399                        if (*flags & REF_BAD_NAME)
1400                                *flags |= REF_ISBROKEN;
1401                        return refname;
1402                }
1403
1404                *flags |= read_flags;
1405
1406                if (!(read_flags & REF_ISSYMREF)) {
1407                        if (*flags & REF_BAD_NAME) {
1408                                hashclr(sha1);
1409                                *flags |= REF_ISBROKEN;
1410                        }
1411                        return refname;
1412                }
1413
1414                refname = sb_refname.buf;
1415                if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1416                        hashclr(sha1);
1417                        return refname;
1418                }
1419                if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1420                        if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1421                            !refname_is_safe(refname)) {
1422                                errno = EINVAL;
1423                                return NULL;
1424                        }
1425
1426                        *flags |= REF_ISBROKEN | REF_BAD_NAME;
1427                }
1428        }
1429
1430        errno = ELOOP;
1431        return NULL;
1432}
1433
1434/* backend functions */
1435int refs_init_db(struct strbuf *err)
1436{
1437        struct ref_store *refs = get_main_ref_store();
1438
1439        return refs->be->init_db(refs, err);
1440}
1441
1442const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1443                               unsigned char *sha1, int *flags)
1444{
1445        return refs_resolve_ref_unsafe(get_main_ref_store(), refname,
1446                                       resolve_flags, sha1, flags);
1447}
1448
1449int resolve_gitlink_ref(const char *submodule, const char *refname,
1450                        unsigned char *sha1)
1451{
1452        size_t len = strlen(submodule);
1453        struct ref_store *refs;
1454        int flags;
1455
1456        while (len && submodule[len - 1] == '/')
1457                len--;
1458
1459        if (!len)
1460                return -1;
1461
1462        if (submodule[len]) {
1463                /* We need to strip off one or more trailing slashes */
1464                char *stripped = xmemdupz(submodule, len);
1465
1466                refs = get_submodule_ref_store(stripped);
1467                free(stripped);
1468        } else {
1469                refs = get_submodule_ref_store(submodule);
1470        }
1471
1472        if (!refs)
1473                return -1;
1474
1475        if (!refs_resolve_ref_unsafe(refs, refname, 0, sha1, &flags) ||
1476            is_null_sha1(sha1))
1477                return -1;
1478        return 0;
1479}
1480
1481struct ref_store_hash_entry
1482{
1483        struct hashmap_entry ent; /* must be the first member! */
1484
1485        struct ref_store *refs;
1486
1487        /* NUL-terminated identifier of the ref store: */
1488        char name[FLEX_ARRAY];
1489};
1490
1491static int ref_store_hash_cmp(const void *entry, const void *entry_or_key,
1492                              const void *keydata)
1493{
1494        const struct ref_store_hash_entry *e1 = entry, *e2 = entry_or_key;
1495        const char *name = keydata ? keydata : e2->name;
1496
1497        return strcmp(e1->name, name);
1498}
1499
1500static struct ref_store_hash_entry *alloc_ref_store_hash_entry(
1501                const char *name, struct ref_store *refs)
1502{
1503        struct ref_store_hash_entry *entry;
1504
1505        FLEX_ALLOC_STR(entry, name, name);
1506        hashmap_entry_init(entry, strhash(name));
1507        entry->refs = refs;
1508        return entry;
1509}
1510
1511/* A pointer to the ref_store for the main repository: */
1512static struct ref_store *main_ref_store;
1513
1514/* A hashmap of ref_stores, stored by submodule name: */
1515static struct hashmap submodule_ref_stores;
1516
1517/* A hashmap of ref_stores, stored by worktree id: */
1518static struct hashmap worktree_ref_stores;
1519
1520/*
1521 * Look up a ref store by name. If that ref_store hasn't been
1522 * registered yet, return NULL.
1523 */
1524static struct ref_store *lookup_ref_store_map(struct hashmap *map,
1525                                              const char *name)
1526{
1527        struct ref_store_hash_entry *entry;
1528
1529        if (!map->tablesize)
1530                /* It's initialized on demand in register_ref_store(). */
1531                return NULL;
1532
1533        entry = hashmap_get_from_hash(map, strhash(name), name);
1534        return entry ? entry->refs : NULL;
1535}
1536
1537/*
1538 * Create, record, and return a ref_store instance for the specified
1539 * gitdir.
1540 */
1541static struct ref_store *ref_store_init(const char *gitdir,
1542                                        unsigned int flags)
1543{
1544        const char *be_name = "files";
1545        struct ref_storage_be *be = find_ref_storage_backend(be_name);
1546        struct ref_store *refs;
1547
1548        if (!be)
1549                die("BUG: reference backend %s is unknown", be_name);
1550
1551        refs = be->init(gitdir, flags);
1552        return refs;
1553}
1554
1555struct ref_store *get_main_ref_store(void)
1556{
1557        if (main_ref_store)
1558                return main_ref_store;
1559
1560        main_ref_store = ref_store_init(get_git_dir(), REF_STORE_ALL_CAPS);
1561        return main_ref_store;
1562}
1563
1564/*
1565 * Associate a ref store with a name. It is a fatal error to call this
1566 * function twice for the same name.
1567 */
1568static void register_ref_store_map(struct hashmap *map,
1569                                   const char *type,
1570                                   struct ref_store *refs,
1571                                   const char *name)
1572{
1573        if (!map->tablesize)
1574                hashmap_init(map, ref_store_hash_cmp, 0);
1575
1576        if (hashmap_put(map, alloc_ref_store_hash_entry(name, refs)))
1577                die("BUG: %s ref_store '%s' initialized twice", type, name);
1578}
1579
1580struct ref_store *get_submodule_ref_store(const char *submodule)
1581{
1582        struct strbuf submodule_sb = STRBUF_INIT;
1583        struct ref_store *refs;
1584        int ret;
1585
1586        if (!submodule || !*submodule) {
1587                /*
1588                 * FIXME: This case is ideally not allowed. But that
1589                 * can't happen until we clean up all the callers.
1590                 */
1591                return get_main_ref_store();
1592        }
1593
1594        refs = lookup_ref_store_map(&submodule_ref_stores, submodule);
1595        if (refs)
1596                return refs;
1597
1598        strbuf_addstr(&submodule_sb, submodule);
1599        ret = is_nonbare_repository_dir(&submodule_sb);
1600        strbuf_release(&submodule_sb);
1601        if (!ret)
1602                return NULL;
1603
1604        ret = submodule_to_gitdir(&submodule_sb, submodule);
1605        if (ret) {
1606                strbuf_release(&submodule_sb);
1607                return NULL;
1608        }
1609
1610        /* assume that add_submodule_odb() has been called */
1611        refs = ref_store_init(submodule_sb.buf,
1612                              REF_STORE_READ | REF_STORE_ODB);
1613        register_ref_store_map(&submodule_ref_stores, "submodule",
1614                               refs, submodule);
1615
1616        strbuf_release(&submodule_sb);
1617        return refs;
1618}
1619
1620struct ref_store *get_worktree_ref_store(const struct worktree *wt)
1621{
1622        struct ref_store *refs;
1623        const char *id;
1624
1625        if (wt->is_current)
1626                return get_main_ref_store();
1627
1628        id = wt->id ? wt->id : "/";
1629        refs = lookup_ref_store_map(&worktree_ref_stores, id);
1630        if (refs)
1631                return refs;
1632
1633        if (wt->id)
1634                refs = ref_store_init(git_common_path("worktrees/%s", wt->id),
1635                                      REF_STORE_ALL_CAPS);
1636        else
1637                refs = ref_store_init(get_git_common_dir(),
1638                                      REF_STORE_ALL_CAPS);
1639
1640        if (refs)
1641                register_ref_store_map(&worktree_ref_stores, "worktree",
1642                                       refs, id);
1643        return refs;
1644}
1645
1646void base_ref_store_init(struct ref_store *refs,
1647                         const struct ref_storage_be *be)
1648{
1649        refs->be = be;
1650}
1651
1652/* backend functions */
1653int refs_pack_refs(struct ref_store *refs, unsigned int flags)
1654{
1655        return refs->be->pack_refs(refs, flags);
1656}
1657
1658int refs_peel_ref(struct ref_store *refs, const char *refname,
1659                  unsigned char *sha1)
1660{
1661        return refs->be->peel_ref(refs, refname, sha1);
1662}
1663
1664int peel_ref(const char *refname, unsigned char *sha1)
1665{
1666        return refs_peel_ref(get_main_ref_store(), refname, sha1);
1667}
1668
1669int refs_create_symref(struct ref_store *refs,
1670                       const char *ref_target,
1671                       const char *refs_heads_master,
1672                       const char *logmsg)
1673{
1674        return refs->be->create_symref(refs, ref_target,
1675                                       refs_heads_master,
1676                                       logmsg);
1677}
1678
1679int create_symref(const char *ref_target, const char *refs_heads_master,
1680                  const char *logmsg)
1681{
1682        return refs_create_symref(get_main_ref_store(), ref_target,
1683                                  refs_heads_master, logmsg);
1684}
1685
1686int ref_transaction_commit(struct ref_transaction *transaction,
1687                           struct strbuf *err)
1688{
1689        struct ref_store *refs = transaction->ref_store;
1690
1691        if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
1692                strbuf_addstr(err,
1693                              _("ref updates forbidden inside quarantine environment"));
1694                return -1;
1695        }
1696
1697        return refs->be->transaction_commit(refs, transaction, err);
1698}
1699
1700int refs_verify_refname_available(struct ref_store *refs,
1701                                  const char *refname,
1702                                  const struct string_list *extras,
1703                                  const struct string_list *skip,
1704                                  struct strbuf *err)
1705{
1706        const char *slash;
1707        const char *extra_refname;
1708        struct strbuf dirname = STRBUF_INIT;
1709        struct strbuf referent = STRBUF_INIT;
1710        struct object_id oid;
1711        unsigned int type;
1712        struct ref_iterator *iter;
1713        int ok;
1714        int ret = -1;
1715
1716        /*
1717         * For the sake of comments in this function, suppose that
1718         * refname is "refs/foo/bar".
1719         */
1720
1721        assert(err);
1722
1723        strbuf_grow(&dirname, strlen(refname) + 1);
1724        for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
1725                /* Expand dirname to the new prefix, not including the trailing slash: */
1726                strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
1727
1728                /*
1729                 * We are still at a leading dir of the refname (e.g.,
1730                 * "refs/foo"; if there is a reference with that name,
1731                 * it is a conflict, *unless* it is in skip.
1732                 */
1733                if (skip && string_list_has_string(skip, dirname.buf))
1734                        continue;
1735
1736                if (!refs_read_raw_ref(refs, dirname.buf, oid.hash, &referent, &type)) {
1737                        strbuf_addf(err, "'%s' exists; cannot create '%s'",
1738                                    dirname.buf, refname);
1739                        goto cleanup;
1740                }
1741
1742                if (extras && string_list_has_string(extras, dirname.buf)) {
1743                        strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1744                                    refname, dirname.buf);
1745                        goto cleanup;
1746                }
1747        }
1748
1749        /*
1750         * We are at the leaf of our refname (e.g., "refs/foo/bar").
1751         * There is no point in searching for a reference with that
1752         * name, because a refname isn't considered to conflict with
1753         * itself. But we still need to check for references whose
1754         * names are in the "refs/foo/bar/" namespace, because they
1755         * *do* conflict.
1756         */
1757        strbuf_addstr(&dirname, refname + dirname.len);
1758        strbuf_addch(&dirname, '/');
1759
1760        iter = refs_ref_iterator_begin(refs, dirname.buf, 0,
1761                                       DO_FOR_EACH_INCLUDE_BROKEN);
1762        while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
1763                if (skip &&
1764                    string_list_has_string(skip, iter->refname))
1765                        continue;
1766
1767                strbuf_addf(err, "'%s' exists; cannot create '%s'",
1768                            iter->refname, refname);
1769                ref_iterator_abort(iter);
1770                goto cleanup;
1771        }
1772
1773        if (ok != ITER_DONE)
1774                die("BUG: error while iterating over references");
1775
1776        extra_refname = find_descendant_ref(dirname.buf, extras, skip);
1777        if (extra_refname)
1778                strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
1779                            refname, extra_refname);
1780        else
1781                ret = 0;
1782
1783cleanup:
1784        strbuf_release(&referent);
1785        strbuf_release(&dirname);
1786        return ret;
1787}
1788
1789int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1790{
1791        struct ref_iterator *iter;
1792
1793        iter = refs->be->reflog_iterator_begin(refs);
1794
1795        return do_for_each_ref_iterator(iter, fn, cb_data);
1796}
1797
1798int for_each_reflog(each_ref_fn fn, void *cb_data)
1799{
1800        return refs_for_each_reflog(get_main_ref_store(), fn, cb_data);
1801}
1802
1803int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
1804                                     const char *refname,
1805                                     each_reflog_ent_fn fn,
1806                                     void *cb_data)
1807{
1808        return refs->be->for_each_reflog_ent_reverse(refs, refname,
1809                                                     fn, cb_data);
1810}
1811
1812int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
1813                                void *cb_data)
1814{
1815        return refs_for_each_reflog_ent_reverse(get_main_ref_store(),
1816                                                refname, fn, cb_data);
1817}
1818
1819int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
1820                             each_reflog_ent_fn fn, void *cb_data)
1821{
1822        return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
1823}
1824
1825int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
1826                        void *cb_data)
1827{
1828        return refs_for_each_reflog_ent(get_main_ref_store(), refname,
1829                                        fn, cb_data);
1830}
1831
1832int refs_reflog_exists(struct ref_store *refs, const char *refname)
1833{
1834        return refs->be->reflog_exists(refs, refname);
1835}
1836
1837int reflog_exists(const char *refname)
1838{
1839        return refs_reflog_exists(get_main_ref_store(), refname);
1840}
1841
1842int refs_create_reflog(struct ref_store *refs, const char *refname,
1843                       int force_create, struct strbuf *err)
1844{
1845        return refs->be->create_reflog(refs, refname, force_create, err);
1846}
1847
1848int safe_create_reflog(const char *refname, int force_create,
1849                       struct strbuf *err)
1850{
1851        return refs_create_reflog(get_main_ref_store(), refname,
1852                                  force_create, err);
1853}
1854
1855int refs_delete_reflog(struct ref_store *refs, const char *refname)
1856{
1857        return refs->be->delete_reflog(refs, refname);
1858}
1859
1860int delete_reflog(const char *refname)
1861{
1862        return refs_delete_reflog(get_main_ref_store(), refname);
1863}
1864
1865int refs_reflog_expire(struct ref_store *refs,
1866                       const char *refname, const unsigned char *sha1,
1867                       unsigned int flags,
1868                       reflog_expiry_prepare_fn prepare_fn,
1869                       reflog_expiry_should_prune_fn should_prune_fn,
1870                       reflog_expiry_cleanup_fn cleanup_fn,
1871                       void *policy_cb_data)
1872{
1873        return refs->be->reflog_expire(refs, refname, sha1, flags,
1874                                       prepare_fn, should_prune_fn,
1875                                       cleanup_fn, policy_cb_data);
1876}
1877
1878int reflog_expire(const char *refname, const unsigned char *sha1,
1879                  unsigned int flags,
1880                  reflog_expiry_prepare_fn prepare_fn,
1881                  reflog_expiry_should_prune_fn should_prune_fn,
1882                  reflog_expiry_cleanup_fn cleanup_fn,
1883                  void *policy_cb_data)
1884{
1885        return refs_reflog_expire(get_main_ref_store(),
1886                                  refname, sha1, flags,
1887                                  prepare_fn, should_prune_fn,
1888                                  cleanup_fn, policy_cb_data);
1889}
1890
1891int initial_ref_transaction_commit(struct ref_transaction *transaction,
1892                                   struct strbuf *err)
1893{
1894        struct ref_store *refs = transaction->ref_store;
1895
1896        return refs->be->initial_transaction_commit(refs, transaction, err);
1897}
1898
1899int refs_delete_refs(struct ref_store *refs, struct string_list *refnames,
1900                     unsigned int flags)
1901{
1902        return refs->be->delete_refs(refs, refnames, flags);
1903}
1904
1905int delete_refs(struct string_list *refnames, unsigned int flags)
1906{
1907        return refs_delete_refs(get_main_ref_store(), refnames, flags);
1908}
1909
1910int refs_rename_ref(struct ref_store *refs, const char *oldref,
1911                    const char *newref, const char *logmsg)
1912{
1913        return refs->be->rename_ref(refs, oldref, newref, logmsg);
1914}
1915
1916int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1917{
1918        return refs_rename_ref(get_main_ref_store(), oldref, newref, logmsg);
1919}