l10n: bg.po: Updated Bulgarian translation (4839t)
[git] / 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-store.h"
13 #include "object.h"
14 #include "tag.h"
15 #include "submodule.h"
16 #include "worktree.h"
17 #include "argv-array.h"
18 #include "repository.h"
19
20 /*
21  * List of all available backends
22  */
23 static struct ref_storage_be *refs_backends = &refs_be_files;
24
25 static struct ref_storage_be *find_ref_storage_backend(const char *name)
26 {
27         struct ref_storage_be *be;
28         for (be = refs_backends; be; be = be->next)
29                 if (!strcmp(be->name, name))
30                         return be;
31         return NULL;
32 }
33
34 int ref_storage_backend_exists(const char *name)
35 {
36         return find_ref_storage_backend(name) != NULL;
37 }
38
39 /*
40  * How to handle various characters in refnames:
41  * 0: An acceptable character for refs
42  * 1: End-of-component
43  * 2: ., look for a preceding . to reject .. in refs
44  * 3: {, look for a preceding @ to reject @{ in refs
45  * 4: A bad character: ASCII control characters, and
46  *    ":", "?", "[", "\", "^", "~", SP, or TAB
47  * 5: *, reject unless REFNAME_REFSPEC_PATTERN is set
48  */
49 static unsigned char refname_disposition[256] = {
50         1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
51         4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
52         4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 1,
53         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
54         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
55         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
56         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
57         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
58 };
59
60 /*
61  * Try to read one refname component from the front of refname.
62  * Return the length of the component found, or -1 if the component is
63  * not legal.  It is legal if it is something reasonable to have under
64  * ".git/refs/"; We do not like it if:
65  *
66  * - it begins with ".", or
67  * - it has double dots "..", or
68  * - it has ASCII control characters, or
69  * - it has ":", "?", "[", "\", "^", "~", SP, or TAB anywhere, or
70  * - it has "*" anywhere unless REFNAME_REFSPEC_PATTERN is set, or
71  * - it ends with a "/", or
72  * - it ends with ".lock", or
73  * - it contains a "@{" portion
74  *
75  * When sanitized is not NULL, instead of rejecting the input refname
76  * as an error, try to come up with a usable replacement for the input
77  * refname in it.
78  */
79 static int check_refname_component(const char *refname, int *flags,
80                                    struct strbuf *sanitized)
81 {
82         const char *cp;
83         char last = '\0';
84         size_t component_start = 0; /* garbage - not a reasonable initial value */
85
86         if (sanitized)
87                 component_start = sanitized->len;
88
89         for (cp = refname; ; cp++) {
90                 int ch = *cp & 255;
91                 unsigned char disp = refname_disposition[ch];
92
93                 if (sanitized && disp != 1)
94                         strbuf_addch(sanitized, ch);
95
96                 switch (disp) {
97                 case 1:
98                         goto out;
99                 case 2:
100                         if (last == '.') { /* Refname contains "..". */
101                                 if (sanitized)
102                                         /* collapse ".." to single "." */
103                                         strbuf_setlen(sanitized, sanitized->len - 1);
104                                 else
105                                         return -1;
106                         }
107                         break;
108                 case 3:
109                         if (last == '@') { /* Refname contains "@{". */
110                                 if (sanitized)
111                                         sanitized->buf[sanitized->len-1] = '-';
112                                 else
113                                         return -1;
114                         }
115                         break;
116                 case 4:
117                         /* forbidden char */
118                         if (sanitized)
119                                 sanitized->buf[sanitized->len-1] = '-';
120                         else
121                                 return -1;
122                         break;
123                 case 5:
124                         if (!(*flags & REFNAME_REFSPEC_PATTERN)) {
125                                 /* refspec can't be a pattern */
126                                 if (sanitized)
127                                         sanitized->buf[sanitized->len-1] = '-';
128                                 else
129                                         return -1;
130                         }
131
132                         /*
133                          * Unset the pattern flag so that we only accept
134                          * a single asterisk for one side of refspec.
135                          */
136                         *flags &= ~ REFNAME_REFSPEC_PATTERN;
137                         break;
138                 }
139                 last = ch;
140         }
141 out:
142         if (cp == refname)
143                 return 0; /* Component has zero length. */
144
145         if (refname[0] == '.') { /* Component starts with '.'. */
146                 if (sanitized)
147                         sanitized->buf[component_start] = '-';
148                 else
149                         return -1;
150         }
151         if (cp - refname >= LOCK_SUFFIX_LEN &&
152             !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN)) {
153                 if (!sanitized)
154                         return -1;
155                 /* Refname ends with ".lock". */
156                 while (strbuf_strip_suffix(sanitized, LOCK_SUFFIX)) {
157                         /* try again in case we have .lock.lock */
158                 }
159         }
160         return cp - refname;
161 }
162
163 static int check_or_sanitize_refname(const char *refname, int flags,
164                                      struct strbuf *sanitized)
165 {
166         int component_len, component_count = 0;
167
168         if (!strcmp(refname, "@")) {
169                 /* Refname is a single character '@'. */
170                 if (sanitized)
171                         strbuf_addch(sanitized, '-');
172                 else
173                         return -1;
174         }
175
176         while (1) {
177                 if (sanitized && sanitized->len)
178                         strbuf_complete(sanitized, '/');
179
180                 /* We are at the start of a path component. */
181                 component_len = check_refname_component(refname, &flags,
182                                                         sanitized);
183                 if (sanitized && component_len == 0)
184                         ; /* OK, omit empty component */
185                 else if (component_len <= 0)
186                         return -1;
187
188                 component_count++;
189                 if (refname[component_len] == '\0')
190                         break;
191                 /* Skip to next component. */
192                 refname += component_len + 1;
193         }
194
195         if (refname[component_len - 1] == '.') {
196                 /* Refname ends with '.'. */
197                 if (sanitized)
198                         ; /* omit ending dot */
199                 else
200                         return -1;
201         }
202         if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
203                 return -1; /* Refname has only one component. */
204         return 0;
205 }
206
207 int check_refname_format(const char *refname, int flags)
208 {
209         return check_or_sanitize_refname(refname, flags, NULL);
210 }
211
212 void sanitize_refname_component(const char *refname, struct strbuf *out)
213 {
214         if (check_or_sanitize_refname(refname, REFNAME_ALLOW_ONELEVEL, out))
215                 BUG("sanitizing refname '%s' check returned error", refname);
216 }
217
218 int refname_is_safe(const char *refname)
219 {
220         const char *rest;
221
222         if (skip_prefix(refname, "refs/", &rest)) {
223                 char *buf;
224                 int result;
225                 size_t restlen = strlen(rest);
226
227                 /* rest must not be empty, or start or end with "/" */
228                 if (!restlen || *rest == '/' || rest[restlen - 1] == '/')
229                         return 0;
230
231                 /*
232                  * Does the refname try to escape refs/?
233                  * For example: refs/foo/../bar is safe but refs/foo/../../bar
234                  * is not.
235                  */
236                 buf = xmallocz(restlen);
237                 result = !normalize_path_copy(buf, rest) && !strcmp(buf, rest);
238                 free(buf);
239                 return result;
240         }
241
242         do {
243                 if (!isupper(*refname) && *refname != '_')
244                         return 0;
245                 refname++;
246         } while (*refname);
247         return 1;
248 }
249
250 /*
251  * Return true if refname, which has the specified oid and flags, can
252  * be resolved to an object in the database. If the referred-to object
253  * does not exist, emit a warning and return false.
254  */
255 int ref_resolves_to_object(const char *refname,
256                            const struct object_id *oid,
257                            unsigned int flags)
258 {
259         if (flags & REF_ISBROKEN)
260                 return 0;
261         if (!has_object_file(oid)) {
262                 error(_("%s does not point to a valid object!"), refname);
263                 return 0;
264         }
265         return 1;
266 }
267
268 char *refs_resolve_refdup(struct ref_store *refs,
269                           const char *refname, int resolve_flags,
270                           struct object_id *oid, int *flags)
271 {
272         const char *result;
273
274         result = refs_resolve_ref_unsafe(refs, refname, resolve_flags,
275                                          oid, flags);
276         return xstrdup_or_null(result);
277 }
278
279 char *resolve_refdup(const char *refname, int resolve_flags,
280                      struct object_id *oid, int *flags)
281 {
282         return refs_resolve_refdup(get_main_ref_store(the_repository),
283                                    refname, resolve_flags,
284                                    oid, flags);
285 }
286
287 /* The argument to filter_refs */
288 struct ref_filter {
289         const char *pattern;
290         const char *prefix;
291         each_ref_fn *fn;
292         void *cb_data;
293 };
294
295 int refs_read_ref_full(struct ref_store *refs, const char *refname,
296                        int resolve_flags, struct object_id *oid, int *flags)
297 {
298         if (refs_resolve_ref_unsafe(refs, refname, resolve_flags, oid, flags))
299                 return 0;
300         return -1;
301 }
302
303 int read_ref_full(const char *refname, int resolve_flags, struct object_id *oid, int *flags)
304 {
305         return refs_read_ref_full(get_main_ref_store(the_repository), refname,
306                                   resolve_flags, oid, flags);
307 }
308
309 int read_ref(const char *refname, struct object_id *oid)
310 {
311         return read_ref_full(refname, RESOLVE_REF_READING, oid, NULL);
312 }
313
314 static int refs_ref_exists(struct ref_store *refs, const char *refname)
315 {
316         return !!refs_resolve_ref_unsafe(refs, refname, RESOLVE_REF_READING, NULL, NULL);
317 }
318
319 int ref_exists(const char *refname)
320 {
321         return refs_ref_exists(get_main_ref_store(the_repository), refname);
322 }
323
324 static int match_ref_pattern(const char *refname,
325                              const struct string_list_item *item)
326 {
327         int matched = 0;
328         if (item->util == NULL) {
329                 if (!wildmatch(item->string, refname, 0))
330                         matched = 1;
331         } else {
332                 const char *rest;
333                 if (skip_prefix(refname, item->string, &rest) &&
334                     (!*rest || *rest == '/'))
335                         matched = 1;
336         }
337         return matched;
338 }
339
340 int ref_filter_match(const char *refname,
341                      const struct string_list *include_patterns,
342                      const struct string_list *exclude_patterns)
343 {
344         struct string_list_item *item;
345
346         if (exclude_patterns && exclude_patterns->nr) {
347                 for_each_string_list_item(item, exclude_patterns) {
348                         if (match_ref_pattern(refname, item))
349                                 return 0;
350                 }
351         }
352
353         if (include_patterns && include_patterns->nr) {
354                 int found = 0;
355                 for_each_string_list_item(item, include_patterns) {
356                         if (match_ref_pattern(refname, item)) {
357                                 found = 1;
358                                 break;
359                         }
360                 }
361
362                 if (!found)
363                         return 0;
364         }
365         return 1;
366 }
367
368 static int filter_refs(const char *refname, const struct object_id *oid,
369                            int flags, void *data)
370 {
371         struct ref_filter *filter = (struct ref_filter *)data;
372
373         if (wildmatch(filter->pattern, refname, 0))
374                 return 0;
375         if (filter->prefix)
376                 skip_prefix(refname, filter->prefix, &refname);
377         return filter->fn(refname, oid, flags, filter->cb_data);
378 }
379
380 enum peel_status peel_object(const struct object_id *name, struct object_id *oid)
381 {
382         struct object *o = lookup_unknown_object(name);
383
384         if (o->type == OBJ_NONE) {
385                 int type = oid_object_info(the_repository, name, NULL);
386                 if (type < 0 || !object_as_type(the_repository, o, type, 0))
387                         return PEEL_INVALID;
388         }
389
390         if (o->type != OBJ_TAG)
391                 return PEEL_NON_TAG;
392
393         o = deref_tag_noverify(o);
394         if (!o)
395                 return PEEL_INVALID;
396
397         oidcpy(oid, &o->oid);
398         return PEEL_PEELED;
399 }
400
401 struct warn_if_dangling_data {
402         FILE *fp;
403         const char *refname;
404         const struct string_list *refnames;
405         const char *msg_fmt;
406 };
407
408 static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
409                                    int flags, void *cb_data)
410 {
411         struct warn_if_dangling_data *d = cb_data;
412         const char *resolves_to;
413
414         if (!(flags & REF_ISSYMREF))
415                 return 0;
416
417         resolves_to = resolve_ref_unsafe(refname, 0, NULL, NULL);
418         if (!resolves_to
419             || (d->refname
420                 ? strcmp(resolves_to, d->refname)
421                 : !string_list_has_string(d->refnames, resolves_to))) {
422                 return 0;
423         }
424
425         fprintf(d->fp, d->msg_fmt, refname);
426         fputc('\n', d->fp);
427         return 0;
428 }
429
430 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
431 {
432         struct warn_if_dangling_data data;
433
434         data.fp = fp;
435         data.refname = refname;
436         data.refnames = NULL;
437         data.msg_fmt = msg_fmt;
438         for_each_rawref(warn_if_dangling_symref, &data);
439 }
440
441 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
442 {
443         struct warn_if_dangling_data data;
444
445         data.fp = fp;
446         data.refname = NULL;
447         data.refnames = refnames;
448         data.msg_fmt = msg_fmt;
449         for_each_rawref(warn_if_dangling_symref, &data);
450 }
451
452 int refs_for_each_tag_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
453 {
454         return refs_for_each_ref_in(refs, "refs/tags/", fn, cb_data);
455 }
456
457 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
458 {
459         return refs_for_each_tag_ref(get_main_ref_store(the_repository), fn, cb_data);
460 }
461
462 int refs_for_each_branch_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
463 {
464         return refs_for_each_ref_in(refs, "refs/heads/", fn, cb_data);
465 }
466
467 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
468 {
469         return refs_for_each_branch_ref(get_main_ref_store(the_repository), fn, cb_data);
470 }
471
472 int refs_for_each_remote_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
473 {
474         return refs_for_each_ref_in(refs, "refs/remotes/", fn, cb_data);
475 }
476
477 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
478 {
479         return refs_for_each_remote_ref(get_main_ref_store(the_repository), fn, cb_data);
480 }
481
482 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
483 {
484         struct strbuf buf = STRBUF_INIT;
485         int ret = 0;
486         struct object_id oid;
487         int flag;
488
489         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
490         if (!read_ref_full(buf.buf, RESOLVE_REF_READING, &oid, &flag))
491                 ret = fn(buf.buf, &oid, flag, cb_data);
492         strbuf_release(&buf);
493
494         return ret;
495 }
496
497 void normalize_glob_ref(struct string_list_item *item, const char *prefix,
498                         const char *pattern)
499 {
500         struct strbuf normalized_pattern = STRBUF_INIT;
501
502         if (*pattern == '/')
503                 BUG("pattern must not start with '/'");
504
505         if (prefix) {
506                 strbuf_addstr(&normalized_pattern, prefix);
507         }
508         else if (!starts_with(pattern, "refs/"))
509                 strbuf_addstr(&normalized_pattern, "refs/");
510         strbuf_addstr(&normalized_pattern, pattern);
511         strbuf_strip_suffix(&normalized_pattern, "/");
512
513         item->string = strbuf_detach(&normalized_pattern, NULL);
514         item->util = has_glob_specials(pattern) ? NULL : item->string;
515         strbuf_release(&normalized_pattern);
516 }
517
518 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
519         const char *prefix, void *cb_data)
520 {
521         struct strbuf real_pattern = STRBUF_INIT;
522         struct ref_filter filter;
523         int ret;
524
525         if (!prefix && !starts_with(pattern, "refs/"))
526                 strbuf_addstr(&real_pattern, "refs/");
527         else if (prefix)
528                 strbuf_addstr(&real_pattern, prefix);
529         strbuf_addstr(&real_pattern, pattern);
530
531         if (!has_glob_specials(pattern)) {
532                 /* Append implied '/' '*' if not present. */
533                 strbuf_complete(&real_pattern, '/');
534                 /* No need to check for '*', there is none. */
535                 strbuf_addch(&real_pattern, '*');
536         }
537
538         filter.pattern = real_pattern.buf;
539         filter.prefix = prefix;
540         filter.fn = fn;
541         filter.cb_data = cb_data;
542         ret = for_each_ref(filter_refs, &filter);
543
544         strbuf_release(&real_pattern);
545         return ret;
546 }
547
548 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
549 {
550         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
551 }
552
553 const char *prettify_refname(const char *name)
554 {
555         if (skip_prefix(name, "refs/heads/", &name) ||
556             skip_prefix(name, "refs/tags/", &name) ||
557             skip_prefix(name, "refs/remotes/", &name))
558                 ; /* nothing */
559         return name;
560 }
561
562 static const char *ref_rev_parse_rules[] = {
563         "%.*s",
564         "refs/%.*s",
565         "refs/tags/%.*s",
566         "refs/heads/%.*s",
567         "refs/remotes/%.*s",
568         "refs/remotes/%.*s/HEAD",
569         NULL
570 };
571
572 #define NUM_REV_PARSE_RULES (ARRAY_SIZE(ref_rev_parse_rules) - 1)
573
574 /*
575  * Is it possible that the caller meant full_name with abbrev_name?
576  * If so return a non-zero value to signal "yes"; the magnitude of
577  * the returned value gives the precedence used for disambiguation.
578  *
579  * If abbrev_name cannot mean full_name, return 0.
580  */
581 int refname_match(const char *abbrev_name, const char *full_name)
582 {
583         const char **p;
584         const int abbrev_name_len = strlen(abbrev_name);
585         const int num_rules = NUM_REV_PARSE_RULES;
586
587         for (p = ref_rev_parse_rules; *p; p++)
588                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name)))
589                         return &ref_rev_parse_rules[num_rules] - p;
590
591         return 0;
592 }
593
594 /*
595  * Given a 'prefix' expand it by the rules in 'ref_rev_parse_rules' and add
596  * the results to 'prefixes'
597  */
598 void expand_ref_prefix(struct argv_array *prefixes, const char *prefix)
599 {
600         const char **p;
601         int len = strlen(prefix);
602
603         for (p = ref_rev_parse_rules; *p; p++)
604                 argv_array_pushf(prefixes, *p, len, prefix);
605 }
606
607 /*
608  * *string and *len will only be substituted, and *string returned (for
609  * later free()ing) if the string passed in is a magic short-hand form
610  * to name a branch.
611  */
612 static char *substitute_branch_name(struct repository *r,
613                                     const char **string, int *len)
614 {
615         struct strbuf buf = STRBUF_INIT;
616         int ret = repo_interpret_branch_name(r, *string, *len, &buf, 0);
617
618         if (ret == *len) {
619                 size_t size;
620                 *string = strbuf_detach(&buf, &size);
621                 *len = size;
622                 return (char *)*string;
623         }
624
625         return NULL;
626 }
627
628 int repo_dwim_ref(struct repository *r, const char *str, int len,
629                   struct object_id *oid, char **ref)
630 {
631         char *last_branch = substitute_branch_name(r, &str, &len);
632         int   refs_found  = expand_ref(r, str, len, oid, ref);
633         free(last_branch);
634         return refs_found;
635 }
636
637 int dwim_ref(const char *str, int len, struct object_id *oid, char **ref)
638 {
639         return repo_dwim_ref(the_repository, str, len, oid, ref);
640 }
641
642 int expand_ref(struct repository *repo, const char *str, int len,
643                struct object_id *oid, char **ref)
644 {
645         const char **p, *r;
646         int refs_found = 0;
647         struct strbuf fullref = STRBUF_INIT;
648
649         *ref = NULL;
650         for (p = ref_rev_parse_rules; *p; p++) {
651                 struct object_id oid_from_ref;
652                 struct object_id *this_result;
653                 int flag;
654
655                 this_result = refs_found ? &oid_from_ref : oid;
656                 strbuf_reset(&fullref);
657                 strbuf_addf(&fullref, *p, len, str);
658                 r = refs_resolve_ref_unsafe(get_main_ref_store(repo),
659                                             fullref.buf, RESOLVE_REF_READING,
660                                             this_result, &flag);
661                 if (r) {
662                         if (!refs_found++)
663                                 *ref = xstrdup(r);
664                         if (!warn_ambiguous_refs)
665                                 break;
666                 } else if ((flag & REF_ISSYMREF) && strcmp(fullref.buf, "HEAD")) {
667                         warning(_("ignoring dangling symref %s"), fullref.buf);
668                 } else if ((flag & REF_ISBROKEN) && strchr(fullref.buf, '/')) {
669                         warning(_("ignoring broken ref %s"), fullref.buf);
670                 }
671         }
672         strbuf_release(&fullref);
673         return refs_found;
674 }
675
676 int repo_dwim_log(struct repository *r, const char *str, int len,
677                   struct object_id *oid, char **log)
678 {
679         struct ref_store *refs = get_main_ref_store(r);
680         char *last_branch = substitute_branch_name(r, &str, &len);
681         const char **p;
682         int logs_found = 0;
683         struct strbuf path = STRBUF_INIT;
684
685         *log = NULL;
686         for (p = ref_rev_parse_rules; *p; p++) {
687                 struct object_id hash;
688                 const char *ref, *it;
689
690                 strbuf_reset(&path);
691                 strbuf_addf(&path, *p, len, str);
692                 ref = refs_resolve_ref_unsafe(refs, path.buf,
693                                               RESOLVE_REF_READING,
694                                               &hash, NULL);
695                 if (!ref)
696                         continue;
697                 if (refs_reflog_exists(refs, path.buf))
698                         it = path.buf;
699                 else if (strcmp(ref, path.buf) &&
700                          refs_reflog_exists(refs, ref))
701                         it = ref;
702                 else
703                         continue;
704                 if (!logs_found++) {
705                         *log = xstrdup(it);
706                         oidcpy(oid, &hash);
707                 }
708                 if (!warn_ambiguous_refs)
709                         break;
710         }
711         strbuf_release(&path);
712         free(last_branch);
713         return logs_found;
714 }
715
716 int dwim_log(const char *str, int len, struct object_id *oid, char **log)
717 {
718         return repo_dwim_log(the_repository, str, len, oid, log);
719 }
720
721 static int is_per_worktree_ref(const char *refname)
722 {
723         return !strcmp(refname, "HEAD") ||
724                 starts_with(refname, "refs/worktree/") ||
725                 starts_with(refname, "refs/bisect/") ||
726                 starts_with(refname, "refs/rewritten/");
727 }
728
729 static int is_pseudoref_syntax(const char *refname)
730 {
731         const char *c;
732
733         for (c = refname; *c; c++) {
734                 if (!isupper(*c) && *c != '-' && *c != '_')
735                         return 0;
736         }
737
738         return 1;
739 }
740
741 static int is_main_pseudoref_syntax(const char *refname)
742 {
743         return skip_prefix(refname, "main-worktree/", &refname) &&
744                 *refname &&
745                 is_pseudoref_syntax(refname);
746 }
747
748 static int is_other_pseudoref_syntax(const char *refname)
749 {
750         if (!skip_prefix(refname, "worktrees/", &refname))
751                 return 0;
752         refname = strchr(refname, '/');
753         if (!refname || !refname[1])
754                 return 0;
755         return is_pseudoref_syntax(refname + 1);
756 }
757
758 enum ref_type ref_type(const char *refname)
759 {
760         if (is_per_worktree_ref(refname))
761                 return REF_TYPE_PER_WORKTREE;
762         if (is_pseudoref_syntax(refname))
763                 return REF_TYPE_PSEUDOREF;
764         if (is_main_pseudoref_syntax(refname))
765                 return REF_TYPE_MAIN_PSEUDOREF;
766         if (is_other_pseudoref_syntax(refname))
767                 return REF_TYPE_OTHER_PSEUDOREF;
768         return REF_TYPE_NORMAL;
769 }
770
771 long get_files_ref_lock_timeout_ms(void)
772 {
773         static int configured = 0;
774
775         /* The default timeout is 100 ms: */
776         static int timeout_ms = 100;
777
778         if (!configured) {
779                 git_config_get_int("core.filesreflocktimeout", &timeout_ms);
780                 configured = 1;
781         }
782
783         return timeout_ms;
784 }
785
786 static int write_pseudoref(const char *pseudoref, const struct object_id *oid,
787                            const struct object_id *old_oid, struct strbuf *err)
788 {
789         const char *filename;
790         int fd;
791         struct lock_file lock = LOCK_INIT;
792         struct strbuf buf = STRBUF_INIT;
793         int ret = -1;
794
795         if (!oid)
796                 return 0;
797
798         strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
799
800         filename = git_path("%s", pseudoref);
801         fd = hold_lock_file_for_update_timeout(&lock, filename, 0,
802                                                get_files_ref_lock_timeout_ms());
803         if (fd < 0) {
804                 strbuf_addf(err, _("could not open '%s' for writing: %s"),
805                             filename, strerror(errno));
806                 goto done;
807         }
808
809         if (old_oid) {
810                 struct object_id actual_old_oid;
811
812                 if (read_ref(pseudoref, &actual_old_oid)) {
813                         if (!is_null_oid(old_oid)) {
814                                 strbuf_addf(err, _("could not read ref '%s'"),
815                                             pseudoref);
816                                 rollback_lock_file(&lock);
817                                 goto done;
818                         }
819                 } else if (is_null_oid(old_oid)) {
820                         strbuf_addf(err, _("ref '%s' already exists"),
821                                     pseudoref);
822                         rollback_lock_file(&lock);
823                         goto done;
824                 } else if (!oideq(&actual_old_oid, old_oid)) {
825                         strbuf_addf(err, _("unexpected object ID when writing '%s'"),
826                                     pseudoref);
827                         rollback_lock_file(&lock);
828                         goto done;
829                 }
830         }
831
832         if (write_in_full(fd, buf.buf, buf.len) < 0) {
833                 strbuf_addf(err, _("could not write to '%s'"), filename);
834                 rollback_lock_file(&lock);
835                 goto done;
836         }
837
838         commit_lock_file(&lock);
839         ret = 0;
840 done:
841         strbuf_release(&buf);
842         return ret;
843 }
844
845 static int delete_pseudoref(const char *pseudoref, const struct object_id *old_oid)
846 {
847         const char *filename;
848
849         filename = git_path("%s", pseudoref);
850
851         if (old_oid && !is_null_oid(old_oid)) {
852                 struct lock_file lock = LOCK_INIT;
853                 int fd;
854                 struct object_id actual_old_oid;
855
856                 fd = hold_lock_file_for_update_timeout(
857                                 &lock, filename, 0,
858                                 get_files_ref_lock_timeout_ms());
859                 if (fd < 0) {
860                         error_errno(_("could not open '%s' for writing"),
861                                     filename);
862                         return -1;
863                 }
864                 if (read_ref(pseudoref, &actual_old_oid))
865                         die(_("could not read ref '%s'"), pseudoref);
866                 if (!oideq(&actual_old_oid, old_oid)) {
867                         error(_("unexpected object ID when deleting '%s'"),
868                               pseudoref);
869                         rollback_lock_file(&lock);
870                         return -1;
871                 }
872
873                 unlink(filename);
874                 rollback_lock_file(&lock);
875         } else {
876                 unlink(filename);
877         }
878
879         return 0;
880 }
881
882 int refs_delete_ref(struct ref_store *refs, const char *msg,
883                     const char *refname,
884                     const struct object_id *old_oid,
885                     unsigned int flags)
886 {
887         struct ref_transaction *transaction;
888         struct strbuf err = STRBUF_INIT;
889
890         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
891                 assert(refs == get_main_ref_store(the_repository));
892                 return delete_pseudoref(refname, old_oid);
893         }
894
895         transaction = ref_store_transaction_begin(refs, &err);
896         if (!transaction ||
897             ref_transaction_delete(transaction, refname, old_oid,
898                                    flags, msg, &err) ||
899             ref_transaction_commit(transaction, &err)) {
900                 error("%s", err.buf);
901                 ref_transaction_free(transaction);
902                 strbuf_release(&err);
903                 return 1;
904         }
905         ref_transaction_free(transaction);
906         strbuf_release(&err);
907         return 0;
908 }
909
910 int delete_ref(const char *msg, const char *refname,
911                const struct object_id *old_oid, unsigned int flags)
912 {
913         return refs_delete_ref(get_main_ref_store(the_repository), msg, refname,
914                                old_oid, flags);
915 }
916
917 void copy_reflog_msg(struct strbuf *sb, const char *msg)
918 {
919         char c;
920         int wasspace = 1;
921
922         strbuf_addch(sb, '\t');
923         while ((c = *msg++)) {
924                 if (wasspace && isspace(c))
925                         continue;
926                 wasspace = isspace(c);
927                 if (wasspace)
928                         c = ' ';
929                 strbuf_addch(sb, c);
930         }
931         strbuf_rtrim(sb);
932 }
933
934 int should_autocreate_reflog(const char *refname)
935 {
936         switch (log_all_ref_updates) {
937         case LOG_REFS_ALWAYS:
938                 return 1;
939         case LOG_REFS_NORMAL:
940                 return starts_with(refname, "refs/heads/") ||
941                         starts_with(refname, "refs/remotes/") ||
942                         starts_with(refname, "refs/notes/") ||
943                         !strcmp(refname, "HEAD");
944         default:
945                 return 0;
946         }
947 }
948
949 int is_branch(const char *refname)
950 {
951         return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
952 }
953
954 struct read_ref_at_cb {
955         const char *refname;
956         timestamp_t at_time;
957         int cnt;
958         int reccnt;
959         struct object_id *oid;
960         int found_it;
961
962         struct object_id ooid;
963         struct object_id noid;
964         int tz;
965         timestamp_t date;
966         char **msg;
967         timestamp_t *cutoff_time;
968         int *cutoff_tz;
969         int *cutoff_cnt;
970 };
971
972 static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
973                 const char *email, timestamp_t timestamp, int tz,
974                 const char *message, void *cb_data)
975 {
976         struct read_ref_at_cb *cb = cb_data;
977
978         cb->reccnt++;
979         cb->tz = tz;
980         cb->date = timestamp;
981
982         if (timestamp <= cb->at_time || cb->cnt == 0) {
983                 if (cb->msg)
984                         *cb->msg = xstrdup(message);
985                 if (cb->cutoff_time)
986                         *cb->cutoff_time = timestamp;
987                 if (cb->cutoff_tz)
988                         *cb->cutoff_tz = tz;
989                 if (cb->cutoff_cnt)
990                         *cb->cutoff_cnt = cb->reccnt - 1;
991                 /*
992                  * we have not yet updated cb->[n|o]oid so they still
993                  * hold the values for the previous record.
994                  */
995                 if (!is_null_oid(&cb->ooid)) {
996                         oidcpy(cb->oid, noid);
997                         if (!oideq(&cb->ooid, noid))
998                                 warning(_("log for ref %s has gap after %s"),
999                                         cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
1000                 }
1001                 else if (cb->date == cb->at_time)
1002                         oidcpy(cb->oid, noid);
1003                 else if (!oideq(noid, cb->oid))
1004                         warning(_("log for ref %s unexpectedly ended on %s"),
1005                                 cb->refname, show_date(cb->date, cb->tz,
1006                                                        DATE_MODE(RFC2822)));
1007                 oidcpy(&cb->ooid, ooid);
1008                 oidcpy(&cb->noid, noid);
1009                 cb->found_it = 1;
1010                 return 1;
1011         }
1012         oidcpy(&cb->ooid, ooid);
1013         oidcpy(&cb->noid, noid);
1014         if (cb->cnt > 0)
1015                 cb->cnt--;
1016         return 0;
1017 }
1018
1019 static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
1020                                   const char *email, timestamp_t timestamp,
1021                                   int tz, const char *message, void *cb_data)
1022 {
1023         struct read_ref_at_cb *cb = cb_data;
1024
1025         if (cb->msg)
1026                 *cb->msg = xstrdup(message);
1027         if (cb->cutoff_time)
1028                 *cb->cutoff_time = timestamp;
1029         if (cb->cutoff_tz)
1030                 *cb->cutoff_tz = tz;
1031         if (cb->cutoff_cnt)
1032                 *cb->cutoff_cnt = cb->reccnt;
1033         oidcpy(cb->oid, ooid);
1034         if (is_null_oid(cb->oid))
1035                 oidcpy(cb->oid, noid);
1036         /* We just want the first entry */
1037         return 1;
1038 }
1039
1040 int read_ref_at(struct ref_store *refs, const char *refname,
1041                 unsigned int flags, timestamp_t at_time, int cnt,
1042                 struct object_id *oid, char **msg,
1043                 timestamp_t *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
1044 {
1045         struct read_ref_at_cb cb;
1046
1047         memset(&cb, 0, sizeof(cb));
1048         cb.refname = refname;
1049         cb.at_time = at_time;
1050         cb.cnt = cnt;
1051         cb.msg = msg;
1052         cb.cutoff_time = cutoff_time;
1053         cb.cutoff_tz = cutoff_tz;
1054         cb.cutoff_cnt = cutoff_cnt;
1055         cb.oid = oid;
1056
1057         refs_for_each_reflog_ent_reverse(refs, refname, read_ref_at_ent, &cb);
1058
1059         if (!cb.reccnt) {
1060                 if (flags & GET_OID_QUIETLY)
1061                         exit(128);
1062                 else
1063                         die(_("log for %s is empty"), refname);
1064         }
1065         if (cb.found_it)
1066                 return 0;
1067
1068         refs_for_each_reflog_ent(refs, refname, read_ref_at_ent_oldest, &cb);
1069
1070         return 1;
1071 }
1072
1073 struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
1074                                                     struct strbuf *err)
1075 {
1076         struct ref_transaction *tr;
1077         assert(err);
1078
1079         tr = xcalloc(1, sizeof(struct ref_transaction));
1080         tr->ref_store = refs;
1081         return tr;
1082 }
1083
1084 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
1085 {
1086         return ref_store_transaction_begin(get_main_ref_store(the_repository), err);
1087 }
1088
1089 void ref_transaction_free(struct ref_transaction *transaction)
1090 {
1091         size_t i;
1092
1093         if (!transaction)
1094                 return;
1095
1096         switch (transaction->state) {
1097         case REF_TRANSACTION_OPEN:
1098         case REF_TRANSACTION_CLOSED:
1099                 /* OK */
1100                 break;
1101         case REF_TRANSACTION_PREPARED:
1102                 BUG("free called on a prepared reference transaction");
1103                 break;
1104         default:
1105                 BUG("unexpected reference transaction state");
1106                 break;
1107         }
1108
1109         for (i = 0; i < transaction->nr; i++) {
1110                 free(transaction->updates[i]->msg);
1111                 free(transaction->updates[i]);
1112         }
1113         free(transaction->updates);
1114         free(transaction);
1115 }
1116
1117 struct ref_update *ref_transaction_add_update(
1118                 struct ref_transaction *transaction,
1119                 const char *refname, unsigned int flags,
1120                 const struct object_id *new_oid,
1121                 const struct object_id *old_oid,
1122                 const char *msg)
1123 {
1124         struct ref_update *update;
1125
1126         if (transaction->state != REF_TRANSACTION_OPEN)
1127                 BUG("update called for transaction that is not open");
1128
1129         FLEX_ALLOC_STR(update, refname, refname);
1130         ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
1131         transaction->updates[transaction->nr++] = update;
1132
1133         update->flags = flags;
1134
1135         if (flags & REF_HAVE_NEW)
1136                 oidcpy(&update->new_oid, new_oid);
1137         if (flags & REF_HAVE_OLD)
1138                 oidcpy(&update->old_oid, old_oid);
1139         update->msg = xstrdup_or_null(msg);
1140         return update;
1141 }
1142
1143 int ref_transaction_update(struct ref_transaction *transaction,
1144                            const char *refname,
1145                            const struct object_id *new_oid,
1146                            const struct object_id *old_oid,
1147                            unsigned int flags, const char *msg,
1148                            struct strbuf *err)
1149 {
1150         assert(err);
1151
1152         if ((new_oid && !is_null_oid(new_oid)) ?
1153             check_refname_format(refname, REFNAME_ALLOW_ONELEVEL) :
1154             !refname_is_safe(refname)) {
1155                 strbuf_addf(err, _("refusing to update ref with bad name '%s'"),
1156                             refname);
1157                 return -1;
1158         }
1159
1160         if (flags & ~REF_TRANSACTION_UPDATE_ALLOWED_FLAGS)
1161                 BUG("illegal flags 0x%x passed to ref_transaction_update()", flags);
1162
1163         flags |= (new_oid ? REF_HAVE_NEW : 0) | (old_oid ? REF_HAVE_OLD : 0);
1164
1165         ref_transaction_add_update(transaction, refname, flags,
1166                                    new_oid, old_oid, msg);
1167         return 0;
1168 }
1169
1170 int ref_transaction_create(struct ref_transaction *transaction,
1171                            const char *refname,
1172                            const struct object_id *new_oid,
1173                            unsigned int flags, const char *msg,
1174                            struct strbuf *err)
1175 {
1176         if (!new_oid || is_null_oid(new_oid))
1177                 BUG("create called without valid new_oid");
1178         return ref_transaction_update(transaction, refname, new_oid,
1179                                       &null_oid, flags, msg, err);
1180 }
1181
1182 int ref_transaction_delete(struct ref_transaction *transaction,
1183                            const char *refname,
1184                            const struct object_id *old_oid,
1185                            unsigned int flags, const char *msg,
1186                            struct strbuf *err)
1187 {
1188         if (old_oid && is_null_oid(old_oid))
1189                 BUG("delete called with old_oid set to zeros");
1190         return ref_transaction_update(transaction, refname,
1191                                       &null_oid, old_oid,
1192                                       flags, msg, err);
1193 }
1194
1195 int ref_transaction_verify(struct ref_transaction *transaction,
1196                            const char *refname,
1197                            const struct object_id *old_oid,
1198                            unsigned int flags,
1199                            struct strbuf *err)
1200 {
1201         if (!old_oid)
1202                 BUG("verify called with old_oid set to NULL");
1203         return ref_transaction_update(transaction, refname,
1204                                       NULL, old_oid,
1205                                       flags, NULL, err);
1206 }
1207
1208 int refs_update_ref(struct ref_store *refs, const char *msg,
1209                     const char *refname, const struct object_id *new_oid,
1210                     const struct object_id *old_oid, unsigned int flags,
1211                     enum action_on_err onerr)
1212 {
1213         struct ref_transaction *t = NULL;
1214         struct strbuf err = STRBUF_INIT;
1215         int ret = 0;
1216
1217         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
1218                 assert(refs == get_main_ref_store(the_repository));
1219                 ret = write_pseudoref(refname, new_oid, old_oid, &err);
1220         } else {
1221                 t = ref_store_transaction_begin(refs, &err);
1222                 if (!t ||
1223                     ref_transaction_update(t, refname, new_oid, old_oid,
1224                                            flags, msg, &err) ||
1225                     ref_transaction_commit(t, &err)) {
1226                         ret = 1;
1227                         ref_transaction_free(t);
1228                 }
1229         }
1230         if (ret) {
1231                 const char *str = _("update_ref failed for ref '%s': %s");
1232
1233                 switch (onerr) {
1234                 case UPDATE_REFS_MSG_ON_ERR:
1235                         error(str, refname, err.buf);
1236                         break;
1237                 case UPDATE_REFS_DIE_ON_ERR:
1238                         die(str, refname, err.buf);
1239                         break;
1240                 case UPDATE_REFS_QUIET_ON_ERR:
1241                         break;
1242                 }
1243                 strbuf_release(&err);
1244                 return 1;
1245         }
1246         strbuf_release(&err);
1247         if (t)
1248                 ref_transaction_free(t);
1249         return 0;
1250 }
1251
1252 int update_ref(const char *msg, const char *refname,
1253                const struct object_id *new_oid,
1254                const struct object_id *old_oid,
1255                unsigned int flags, enum action_on_err onerr)
1256 {
1257         return refs_update_ref(get_main_ref_store(the_repository), msg, refname, new_oid,
1258                                old_oid, flags, onerr);
1259 }
1260
1261 char *refs_shorten_unambiguous_ref(struct ref_store *refs,
1262                                    const char *refname, int strict)
1263 {
1264         int i;
1265         static char **scanf_fmts;
1266         static int nr_rules;
1267         char *short_name;
1268         struct strbuf resolved_buf = STRBUF_INIT;
1269
1270         if (!nr_rules) {
1271                 /*
1272                  * Pre-generate scanf formats from ref_rev_parse_rules[].
1273                  * Generate a format suitable for scanf from a
1274                  * ref_rev_parse_rules rule by interpolating "%s" at the
1275                  * location of the "%.*s".
1276                  */
1277                 size_t total_len = 0;
1278                 size_t offset = 0;
1279
1280                 /* the rule list is NULL terminated, count them first */
1281                 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
1282                         /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
1283                         total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
1284
1285                 scanf_fmts = xmalloc(st_add(st_mult(sizeof(char *), nr_rules), total_len));
1286
1287                 offset = 0;
1288                 for (i = 0; i < nr_rules; i++) {
1289                         assert(offset < total_len);
1290                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
1291                         offset += xsnprintf(scanf_fmts[i], total_len - offset,
1292                                             ref_rev_parse_rules[i], 2, "%s") + 1;
1293                 }
1294         }
1295
1296         /* bail out if there are no rules */
1297         if (!nr_rules)
1298                 return xstrdup(refname);
1299
1300         /* buffer for scanf result, at most refname must fit */
1301         short_name = xstrdup(refname);
1302
1303         /* skip first rule, it will always match */
1304         for (i = nr_rules - 1; i > 0 ; --i) {
1305                 int j;
1306                 int rules_to_fail = i;
1307                 int short_name_len;
1308
1309                 if (1 != sscanf(refname, scanf_fmts[i], short_name))
1310                         continue;
1311
1312                 short_name_len = strlen(short_name);
1313
1314                 /*
1315                  * in strict mode, all (except the matched one) rules
1316                  * must fail to resolve to a valid non-ambiguous ref
1317                  */
1318                 if (strict)
1319                         rules_to_fail = nr_rules;
1320
1321                 /*
1322                  * check if the short name resolves to a valid ref,
1323                  * but use only rules prior to the matched one
1324                  */
1325                 for (j = 0; j < rules_to_fail; j++) {
1326                         const char *rule = ref_rev_parse_rules[j];
1327
1328                         /* skip matched rule */
1329                         if (i == j)
1330                                 continue;
1331
1332                         /*
1333                          * the short name is ambiguous, if it resolves
1334                          * (with this previous rule) to a valid ref
1335                          * read_ref() returns 0 on success
1336                          */
1337                         strbuf_reset(&resolved_buf);
1338                         strbuf_addf(&resolved_buf, rule,
1339                                     short_name_len, short_name);
1340                         if (refs_ref_exists(refs, resolved_buf.buf))
1341                                 break;
1342                 }
1343
1344                 /*
1345                  * short name is non-ambiguous if all previous rules
1346                  * haven't resolved to a valid ref
1347                  */
1348                 if (j == rules_to_fail) {
1349                         strbuf_release(&resolved_buf);
1350                         return short_name;
1351                 }
1352         }
1353
1354         strbuf_release(&resolved_buf);
1355         free(short_name);
1356         return xstrdup(refname);
1357 }
1358
1359 char *shorten_unambiguous_ref(const char *refname, int strict)
1360 {
1361         return refs_shorten_unambiguous_ref(get_main_ref_store(the_repository),
1362                                             refname, strict);
1363 }
1364
1365 static struct string_list *hide_refs;
1366
1367 int parse_hide_refs_config(const char *var, const char *value, const char *section)
1368 {
1369         const char *key;
1370         if (!strcmp("transfer.hiderefs", var) ||
1371             (!parse_config_key(var, section, NULL, NULL, &key) &&
1372              !strcmp(key, "hiderefs"))) {
1373                 char *ref;
1374                 int len;
1375
1376                 if (!value)
1377                         return config_error_nonbool(var);
1378                 ref = xstrdup(value);
1379                 len = strlen(ref);
1380                 while (len && ref[len - 1] == '/')
1381                         ref[--len] = '\0';
1382                 if (!hide_refs) {
1383                         hide_refs = xcalloc(1, sizeof(*hide_refs));
1384                         hide_refs->strdup_strings = 1;
1385                 }
1386                 string_list_append(hide_refs, ref);
1387         }
1388         return 0;
1389 }
1390
1391 int ref_is_hidden(const char *refname, const char *refname_full)
1392 {
1393         int i;
1394
1395         if (!hide_refs)
1396                 return 0;
1397         for (i = hide_refs->nr - 1; i >= 0; i--) {
1398                 const char *match = hide_refs->items[i].string;
1399                 const char *subject;
1400                 int neg = 0;
1401                 const char *p;
1402
1403                 if (*match == '!') {
1404                         neg = 1;
1405                         match++;
1406                 }
1407
1408                 if (*match == '^') {
1409                         subject = refname_full;
1410                         match++;
1411                 } else {
1412                         subject = refname;
1413                 }
1414
1415                 /* refname can be NULL when namespaces are used. */
1416                 if (subject &&
1417                     skip_prefix(subject, match, &p) &&
1418                     (!*p || *p == '/'))
1419                         return !neg;
1420         }
1421         return 0;
1422 }
1423
1424 const char *find_descendant_ref(const char *dirname,
1425                                 const struct string_list *extras,
1426                                 const struct string_list *skip)
1427 {
1428         int pos;
1429
1430         if (!extras)
1431                 return NULL;
1432
1433         /*
1434          * Look at the place where dirname would be inserted into
1435          * extras. If there is an entry at that position that starts
1436          * with dirname (remember, dirname includes the trailing
1437          * slash) and is not in skip, then we have a conflict.
1438          */
1439         for (pos = string_list_find_insert_index(extras, dirname, 0);
1440              pos < extras->nr; pos++) {
1441                 const char *extra_refname = extras->items[pos].string;
1442
1443                 if (!starts_with(extra_refname, dirname))
1444                         break;
1445
1446                 if (!skip || !string_list_has_string(skip, extra_refname))
1447                         return extra_refname;
1448         }
1449         return NULL;
1450 }
1451
1452 int refs_rename_ref_available(struct ref_store *refs,
1453                               const char *old_refname,
1454                               const char *new_refname)
1455 {
1456         struct string_list skip = STRING_LIST_INIT_NODUP;
1457         struct strbuf err = STRBUF_INIT;
1458         int ok;
1459
1460         string_list_insert(&skip, old_refname);
1461         ok = !refs_verify_refname_available(refs, new_refname,
1462                                             NULL, &skip, &err);
1463         if (!ok)
1464                 error("%s", err.buf);
1465
1466         string_list_clear(&skip, 0);
1467         strbuf_release(&err);
1468         return ok;
1469 }
1470
1471 int refs_head_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1472 {
1473         struct object_id oid;
1474         int flag;
1475
1476         if (!refs_read_ref_full(refs, "HEAD", RESOLVE_REF_READING,
1477                                 &oid, &flag))
1478                 return fn("HEAD", &oid, flag, cb_data);
1479
1480         return 0;
1481 }
1482
1483 int head_ref(each_ref_fn fn, void *cb_data)
1484 {
1485         return refs_head_ref(get_main_ref_store(the_repository), fn, cb_data);
1486 }
1487
1488 struct ref_iterator *refs_ref_iterator_begin(
1489                 struct ref_store *refs,
1490                 const char *prefix, int trim, int flags)
1491 {
1492         struct ref_iterator *iter;
1493
1494         if (ref_paranoia < 0)
1495                 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1496         if (ref_paranoia)
1497                 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1498
1499         iter = refs->be->iterator_begin(refs, prefix, flags);
1500
1501         /*
1502          * `iterator_begin()` already takes care of prefix, but we
1503          * might need to do some trimming:
1504          */
1505         if (trim)
1506                 iter = prefix_ref_iterator_begin(iter, "", trim);
1507
1508         /* Sanity check for subclasses: */
1509         if (!iter->ordered)
1510                 BUG("reference iterator is not ordered");
1511
1512         return iter;
1513 }
1514
1515 /*
1516  * Call fn for each reference in the specified submodule for which the
1517  * refname begins with prefix. If trim is non-zero, then trim that
1518  * many characters off the beginning of each refname before passing
1519  * the refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to
1520  * include broken references in the iteration. If fn ever returns a
1521  * non-zero value, stop the iteration and return that value;
1522  * otherwise, return 0.
1523  */
1524 static int do_for_each_repo_ref(struct repository *r, const char *prefix,
1525                                 each_repo_ref_fn fn, int trim, int flags,
1526                                 void *cb_data)
1527 {
1528         struct ref_iterator *iter;
1529         struct ref_store *refs = get_main_ref_store(r);
1530
1531         if (!refs)
1532                 return 0;
1533
1534         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1535
1536         return do_for_each_repo_ref_iterator(r, iter, fn, cb_data);
1537 }
1538
1539 struct do_for_each_ref_help {
1540         each_ref_fn *fn;
1541         void *cb_data;
1542 };
1543
1544 static int do_for_each_ref_helper(struct repository *r,
1545                                   const char *refname,
1546                                   const struct object_id *oid,
1547                                   int flags,
1548                                   void *cb_data)
1549 {
1550         struct do_for_each_ref_help *hp = cb_data;
1551
1552         return hp->fn(refname, oid, flags, hp->cb_data);
1553 }
1554
1555 static int do_for_each_ref(struct ref_store *refs, const char *prefix,
1556                            each_ref_fn fn, int trim, int flags, void *cb_data)
1557 {
1558         struct ref_iterator *iter;
1559         struct do_for_each_ref_help hp = { fn, cb_data };
1560
1561         if (!refs)
1562                 return 0;
1563
1564         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1565
1566         return do_for_each_repo_ref_iterator(the_repository, iter,
1567                                         do_for_each_ref_helper, &hp);
1568 }
1569
1570 int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1571 {
1572         return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
1573 }
1574
1575 int for_each_ref(each_ref_fn fn, void *cb_data)
1576 {
1577         return refs_for_each_ref(get_main_ref_store(the_repository), fn, cb_data);
1578 }
1579
1580 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
1581                          each_ref_fn fn, void *cb_data)
1582 {
1583         return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
1584 }
1585
1586 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1587 {
1588         return refs_for_each_ref_in(get_main_ref_store(the_repository), prefix, fn, cb_data);
1589 }
1590
1591 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1592 {
1593         unsigned int flag = 0;
1594
1595         if (broken)
1596                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1597         return do_for_each_ref(get_main_ref_store(the_repository),
1598                                prefix, fn, 0, flag, cb_data);
1599 }
1600
1601 int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
1602                              each_ref_fn fn, void *cb_data,
1603                              unsigned int broken)
1604 {
1605         unsigned int flag = 0;
1606
1607         if (broken)
1608                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1609         return do_for_each_ref(refs, prefix, fn, 0, flag, cb_data);
1610 }
1611
1612 int for_each_replace_ref(struct repository *r, each_repo_ref_fn fn, void *cb_data)
1613 {
1614         return do_for_each_repo_ref(r, git_replace_ref_base, fn,
1615                                     strlen(git_replace_ref_base),
1616                                     DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1617 }
1618
1619 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1620 {
1621         struct strbuf buf = STRBUF_INIT;
1622         int ret;
1623         strbuf_addf(&buf, "%srefs/", get_git_namespace());
1624         ret = do_for_each_ref(get_main_ref_store(the_repository),
1625                               buf.buf, fn, 0, 0, cb_data);
1626         strbuf_release(&buf);
1627         return ret;
1628 }
1629
1630 int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1631 {
1632         return do_for_each_ref(refs, "", fn, 0,
1633                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1634 }
1635
1636 int for_each_rawref(each_ref_fn fn, void *cb_data)
1637 {
1638         return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
1639 }
1640
1641 int refs_read_raw_ref(struct ref_store *ref_store,
1642                       const char *refname, struct object_id *oid,
1643                       struct strbuf *referent, unsigned int *type)
1644 {
1645         return ref_store->be->read_raw_ref(ref_store, refname, oid, referent, type);
1646 }
1647
1648 /* This function needs to return a meaningful errno on failure */
1649 const char *refs_resolve_ref_unsafe(struct ref_store *refs,
1650                                     const char *refname,
1651                                     int resolve_flags,
1652                                     struct object_id *oid, int *flags)
1653 {
1654         static struct strbuf sb_refname = STRBUF_INIT;
1655         struct object_id unused_oid;
1656         int unused_flags;
1657         int symref_count;
1658
1659         if (!oid)
1660                 oid = &unused_oid;
1661         if (!flags)
1662                 flags = &unused_flags;
1663
1664         *flags = 0;
1665
1666         if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1667                 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1668                     !refname_is_safe(refname)) {
1669                         errno = EINVAL;
1670                         return NULL;
1671                 }
1672
1673                 /*
1674                  * dwim_ref() uses REF_ISBROKEN to distinguish between
1675                  * missing refs and refs that were present but invalid,
1676                  * to complain about the latter to stderr.
1677                  *
1678                  * We don't know whether the ref exists, so don't set
1679                  * REF_ISBROKEN yet.
1680                  */
1681                 *flags |= REF_BAD_NAME;
1682         }
1683
1684         for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
1685                 unsigned int read_flags = 0;
1686
1687                 if (refs_read_raw_ref(refs, refname,
1688                                       oid, &sb_refname, &read_flags)) {
1689                         *flags |= read_flags;
1690
1691                         /* In reading mode, refs must eventually resolve */
1692                         if (resolve_flags & RESOLVE_REF_READING)
1693                                 return NULL;
1694
1695                         /*
1696                          * Otherwise a missing ref is OK. But the files backend
1697                          * may show errors besides ENOENT if there are
1698                          * similarly-named refs.
1699                          */
1700                         if (errno != ENOENT &&
1701                             errno != EISDIR &&
1702                             errno != ENOTDIR)
1703                                 return NULL;
1704
1705                         oidclr(oid);
1706                         if (*flags & REF_BAD_NAME)
1707                                 *flags |= REF_ISBROKEN;
1708                         return refname;
1709                 }
1710
1711                 *flags |= read_flags;
1712
1713                 if (!(read_flags & REF_ISSYMREF)) {
1714                         if (*flags & REF_BAD_NAME) {
1715                                 oidclr(oid);
1716                                 *flags |= REF_ISBROKEN;
1717                         }
1718                         return refname;
1719                 }
1720
1721                 refname = sb_refname.buf;
1722                 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1723                         oidclr(oid);
1724                         return refname;
1725                 }
1726                 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1727                         if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1728                             !refname_is_safe(refname)) {
1729                                 errno = EINVAL;
1730                                 return NULL;
1731                         }
1732
1733                         *flags |= REF_ISBROKEN | REF_BAD_NAME;
1734                 }
1735         }
1736
1737         errno = ELOOP;
1738         return NULL;
1739 }
1740
1741 /* backend functions */
1742 int refs_init_db(struct strbuf *err)
1743 {
1744         struct ref_store *refs = get_main_ref_store(the_repository);
1745
1746         return refs->be->init_db(refs, err);
1747 }
1748
1749 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1750                                struct object_id *oid, int *flags)
1751 {
1752         return refs_resolve_ref_unsafe(get_main_ref_store(the_repository), refname,
1753                                        resolve_flags, oid, flags);
1754 }
1755
1756 int resolve_gitlink_ref(const char *submodule, const char *refname,
1757                         struct object_id *oid)
1758 {
1759         struct ref_store *refs;
1760         int flags;
1761
1762         refs = get_submodule_ref_store(submodule);
1763
1764         if (!refs)
1765                 return -1;
1766
1767         if (!refs_resolve_ref_unsafe(refs, refname, 0, oid, &flags) ||
1768             is_null_oid(oid))
1769                 return -1;
1770         return 0;
1771 }
1772
1773 struct ref_store_hash_entry
1774 {
1775         struct hashmap_entry ent;
1776
1777         struct ref_store *refs;
1778
1779         /* NUL-terminated identifier of the ref store: */
1780         char name[FLEX_ARRAY];
1781 };
1782
1783 static int ref_store_hash_cmp(const void *unused_cmp_data,
1784                               const struct hashmap_entry *eptr,
1785                               const struct hashmap_entry *entry_or_key,
1786                               const void *keydata)
1787 {
1788         const struct ref_store_hash_entry *e1, *e2;
1789         const char *name;
1790
1791         e1 = container_of(eptr, const struct ref_store_hash_entry, ent);
1792         e2 = container_of(entry_or_key, const struct ref_store_hash_entry, ent);
1793         name = keydata ? keydata : e2->name;
1794
1795         return strcmp(e1->name, name);
1796 }
1797
1798 static struct ref_store_hash_entry *alloc_ref_store_hash_entry(
1799                 const char *name, struct ref_store *refs)
1800 {
1801         struct ref_store_hash_entry *entry;
1802
1803         FLEX_ALLOC_STR(entry, name, name);
1804         hashmap_entry_init(&entry->ent, strhash(name));
1805         entry->refs = refs;
1806         return entry;
1807 }
1808
1809 /* A hashmap of ref_stores, stored by submodule name: */
1810 static struct hashmap submodule_ref_stores;
1811
1812 /* A hashmap of ref_stores, stored by worktree id: */
1813 static struct hashmap worktree_ref_stores;
1814
1815 /*
1816  * Look up a ref store by name. If that ref_store hasn't been
1817  * registered yet, return NULL.
1818  */
1819 static struct ref_store *lookup_ref_store_map(struct hashmap *map,
1820                                               const char *name)
1821 {
1822         struct ref_store_hash_entry *entry;
1823         unsigned int hash;
1824
1825         if (!map->tablesize)
1826                 /* It's initialized on demand in register_ref_store(). */
1827                 return NULL;
1828
1829         hash = strhash(name);
1830         entry = hashmap_get_entry_from_hash(map, hash, name,
1831                                         struct ref_store_hash_entry, ent);
1832         return entry ? entry->refs : NULL;
1833 }
1834
1835 /*
1836  * Create, record, and return a ref_store instance for the specified
1837  * gitdir.
1838  */
1839 static struct ref_store *ref_store_init(const char *gitdir,
1840                                         unsigned int flags)
1841 {
1842         const char *be_name = "files";
1843         struct ref_storage_be *be = find_ref_storage_backend(be_name);
1844         struct ref_store *refs;
1845
1846         if (!be)
1847                 BUG("reference backend %s is unknown", be_name);
1848
1849         refs = be->init(gitdir, flags);
1850         return refs;
1851 }
1852
1853 struct ref_store *get_main_ref_store(struct repository *r)
1854 {
1855         if (r->refs)
1856                 return r->refs;
1857
1858         if (!r->gitdir)
1859                 BUG("attempting to get main_ref_store outside of repository");
1860
1861         r->refs = ref_store_init(r->gitdir, REF_STORE_ALL_CAPS);
1862         return r->refs;
1863 }
1864
1865 /*
1866  * Associate a ref store with a name. It is a fatal error to call this
1867  * function twice for the same name.
1868  */
1869 static void register_ref_store_map(struct hashmap *map,
1870                                    const char *type,
1871                                    struct ref_store *refs,
1872                                    const char *name)
1873 {
1874         struct ref_store_hash_entry *entry;
1875
1876         if (!map->tablesize)
1877                 hashmap_init(map, ref_store_hash_cmp, NULL, 0);
1878
1879         entry = alloc_ref_store_hash_entry(name, refs);
1880         if (hashmap_put(map, &entry->ent))
1881                 BUG("%s ref_store '%s' initialized twice", type, name);
1882 }
1883
1884 struct ref_store *get_submodule_ref_store(const char *submodule)
1885 {
1886         struct strbuf submodule_sb = STRBUF_INIT;
1887         struct ref_store *refs;
1888         char *to_free = NULL;
1889         size_t len;
1890
1891         if (!submodule)
1892                 return NULL;
1893
1894         len = strlen(submodule);
1895         while (len && is_dir_sep(submodule[len - 1]))
1896                 len--;
1897         if (!len)
1898                 return NULL;
1899
1900         if (submodule[len])
1901                 /* We need to strip off one or more trailing slashes */
1902                 submodule = to_free = xmemdupz(submodule, len);
1903
1904         refs = lookup_ref_store_map(&submodule_ref_stores, submodule);
1905         if (refs)
1906                 goto done;
1907
1908         strbuf_addstr(&submodule_sb, submodule);
1909         if (!is_nonbare_repository_dir(&submodule_sb))
1910                 goto done;
1911
1912         if (submodule_to_gitdir(&submodule_sb, submodule))
1913                 goto done;
1914
1915         /* assume that add_submodule_odb() has been called */
1916         refs = ref_store_init(submodule_sb.buf,
1917                               REF_STORE_READ | REF_STORE_ODB);
1918         register_ref_store_map(&submodule_ref_stores, "submodule",
1919                                refs, submodule);
1920
1921 done:
1922         strbuf_release(&submodule_sb);
1923         free(to_free);
1924
1925         return refs;
1926 }
1927
1928 struct ref_store *get_worktree_ref_store(const struct worktree *wt)
1929 {
1930         struct ref_store *refs;
1931         const char *id;
1932
1933         if (wt->is_current)
1934                 return get_main_ref_store(the_repository);
1935
1936         id = wt->id ? wt->id : "/";
1937         refs = lookup_ref_store_map(&worktree_ref_stores, id);
1938         if (refs)
1939                 return refs;
1940
1941         if (wt->id)
1942                 refs = ref_store_init(git_common_path("worktrees/%s", wt->id),
1943                                       REF_STORE_ALL_CAPS);
1944         else
1945                 refs = ref_store_init(get_git_common_dir(),
1946                                       REF_STORE_ALL_CAPS);
1947
1948         if (refs)
1949                 register_ref_store_map(&worktree_ref_stores, "worktree",
1950                                        refs, id);
1951         return refs;
1952 }
1953
1954 void base_ref_store_init(struct ref_store *refs,
1955                          const struct ref_storage_be *be)
1956 {
1957         refs->be = be;
1958 }
1959
1960 /* backend functions */
1961 int refs_pack_refs(struct ref_store *refs, unsigned int flags)
1962 {
1963         return refs->be->pack_refs(refs, flags);
1964 }
1965
1966 int refs_peel_ref(struct ref_store *refs, const char *refname,
1967                   struct object_id *oid)
1968 {
1969         int flag;
1970         struct object_id base;
1971
1972         if (current_ref_iter && current_ref_iter->refname == refname) {
1973                 struct object_id peeled;
1974
1975                 if (ref_iterator_peel(current_ref_iter, &peeled))
1976                         return -1;
1977                 oidcpy(oid, &peeled);
1978                 return 0;
1979         }
1980
1981         if (refs_read_ref_full(refs, refname,
1982                                RESOLVE_REF_READING, &base, &flag))
1983                 return -1;
1984
1985         return peel_object(&base, oid);
1986 }
1987
1988 int peel_ref(const char *refname, struct object_id *oid)
1989 {
1990         return refs_peel_ref(get_main_ref_store(the_repository), refname, oid);
1991 }
1992
1993 int refs_create_symref(struct ref_store *refs,
1994                        const char *ref_target,
1995                        const char *refs_heads_master,
1996                        const char *logmsg)
1997 {
1998         return refs->be->create_symref(refs, ref_target,
1999                                        refs_heads_master,
2000                                        logmsg);
2001 }
2002
2003 int create_symref(const char *ref_target, const char *refs_heads_master,
2004                   const char *logmsg)
2005 {
2006         return refs_create_symref(get_main_ref_store(the_repository), ref_target,
2007                                   refs_heads_master, logmsg);
2008 }
2009
2010 int ref_update_reject_duplicates(struct string_list *refnames,
2011                                  struct strbuf *err)
2012 {
2013         size_t i, n = refnames->nr;
2014
2015         assert(err);
2016
2017         for (i = 1; i < n; i++) {
2018                 int cmp = strcmp(refnames->items[i - 1].string,
2019                                  refnames->items[i].string);
2020
2021                 if (!cmp) {
2022                         strbuf_addf(err,
2023                                     _("multiple updates for ref '%s' not allowed"),
2024                                     refnames->items[i].string);
2025                         return 1;
2026                 } else if (cmp > 0) {
2027                         BUG("ref_update_reject_duplicates() received unsorted list");
2028                 }
2029         }
2030         return 0;
2031 }
2032
2033 int ref_transaction_prepare(struct ref_transaction *transaction,
2034                             struct strbuf *err)
2035 {
2036         struct ref_store *refs = transaction->ref_store;
2037
2038         switch (transaction->state) {
2039         case REF_TRANSACTION_OPEN:
2040                 /* Good. */
2041                 break;
2042         case REF_TRANSACTION_PREPARED:
2043                 BUG("prepare called twice on reference transaction");
2044                 break;
2045         case REF_TRANSACTION_CLOSED:
2046                 BUG("prepare called on a closed reference transaction");
2047                 break;
2048         default:
2049                 BUG("unexpected reference transaction state");
2050                 break;
2051         }
2052
2053         if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
2054                 strbuf_addstr(err,
2055                               _("ref updates forbidden inside quarantine environment"));
2056                 return -1;
2057         }
2058
2059         return refs->be->transaction_prepare(refs, transaction, err);
2060 }
2061
2062 int ref_transaction_abort(struct ref_transaction *transaction,
2063                           struct strbuf *err)
2064 {
2065         struct ref_store *refs = transaction->ref_store;
2066         int ret = 0;
2067
2068         switch (transaction->state) {
2069         case REF_TRANSACTION_OPEN:
2070                 /* No need to abort explicitly. */
2071                 break;
2072         case REF_TRANSACTION_PREPARED:
2073                 ret = refs->be->transaction_abort(refs, transaction, err);
2074                 break;
2075         case REF_TRANSACTION_CLOSED:
2076                 BUG("abort called on a closed reference transaction");
2077                 break;
2078         default:
2079                 BUG("unexpected reference transaction state");
2080                 break;
2081         }
2082
2083         ref_transaction_free(transaction);
2084         return ret;
2085 }
2086
2087 int ref_transaction_commit(struct ref_transaction *transaction,
2088                            struct strbuf *err)
2089 {
2090         struct ref_store *refs = transaction->ref_store;
2091         int ret;
2092
2093         switch (transaction->state) {
2094         case REF_TRANSACTION_OPEN:
2095                 /* Need to prepare first. */
2096                 ret = ref_transaction_prepare(transaction, err);
2097                 if (ret)
2098                         return ret;
2099                 break;
2100         case REF_TRANSACTION_PREPARED:
2101                 /* Fall through to finish. */
2102                 break;
2103         case REF_TRANSACTION_CLOSED:
2104                 BUG("commit called on a closed reference transaction");
2105                 break;
2106         default:
2107                 BUG("unexpected reference transaction state");
2108                 break;
2109         }
2110
2111         return refs->be->transaction_finish(refs, transaction, err);
2112 }
2113
2114 int refs_verify_refname_available(struct ref_store *refs,
2115                                   const char *refname,
2116                                   const struct string_list *extras,
2117                                   const struct string_list *skip,
2118                                   struct strbuf *err)
2119 {
2120         const char *slash;
2121         const char *extra_refname;
2122         struct strbuf dirname = STRBUF_INIT;
2123         struct strbuf referent = STRBUF_INIT;
2124         struct object_id oid;
2125         unsigned int type;
2126         struct ref_iterator *iter;
2127         int ok;
2128         int ret = -1;
2129
2130         /*
2131          * For the sake of comments in this function, suppose that
2132          * refname is "refs/foo/bar".
2133          */
2134
2135         assert(err);
2136
2137         strbuf_grow(&dirname, strlen(refname) + 1);
2138         for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
2139                 /* Expand dirname to the new prefix, not including the trailing slash: */
2140                 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
2141
2142                 /*
2143                  * We are still at a leading dir of the refname (e.g.,
2144                  * "refs/foo"; if there is a reference with that name,
2145                  * it is a conflict, *unless* it is in skip.
2146                  */
2147                 if (skip && string_list_has_string(skip, dirname.buf))
2148                         continue;
2149
2150                 if (!refs_read_raw_ref(refs, dirname.buf, &oid, &referent, &type)) {
2151                         strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
2152                                     dirname.buf, refname);
2153                         goto cleanup;
2154                 }
2155
2156                 if (extras && string_list_has_string(extras, dirname.buf)) {
2157                         strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
2158                                     refname, dirname.buf);
2159                         goto cleanup;
2160                 }
2161         }
2162
2163         /*
2164          * We are at the leaf of our refname (e.g., "refs/foo/bar").
2165          * There is no point in searching for a reference with that
2166          * name, because a refname isn't considered to conflict with
2167          * itself. But we still need to check for references whose
2168          * names are in the "refs/foo/bar/" namespace, because they
2169          * *do* conflict.
2170          */
2171         strbuf_addstr(&dirname, refname + dirname.len);
2172         strbuf_addch(&dirname, '/');
2173
2174         iter = refs_ref_iterator_begin(refs, dirname.buf, 0,
2175                                        DO_FOR_EACH_INCLUDE_BROKEN);
2176         while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
2177                 if (skip &&
2178                     string_list_has_string(skip, iter->refname))
2179                         continue;
2180
2181                 strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
2182                             iter->refname, refname);
2183                 ref_iterator_abort(iter);
2184                 goto cleanup;
2185         }
2186
2187         if (ok != ITER_DONE)
2188                 BUG("error while iterating over references");
2189
2190         extra_refname = find_descendant_ref(dirname.buf, extras, skip);
2191         if (extra_refname)
2192                 strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
2193                             refname, extra_refname);
2194         else
2195                 ret = 0;
2196
2197 cleanup:
2198         strbuf_release(&referent);
2199         strbuf_release(&dirname);
2200         return ret;
2201 }
2202
2203 int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2204 {
2205         struct ref_iterator *iter;
2206         struct do_for_each_ref_help hp = { fn, cb_data };
2207
2208         iter = refs->be->reflog_iterator_begin(refs);
2209
2210         return do_for_each_repo_ref_iterator(the_repository, iter,
2211                                              do_for_each_ref_helper, &hp);
2212 }
2213
2214 int for_each_reflog(each_ref_fn fn, void *cb_data)
2215 {
2216         return refs_for_each_reflog(get_main_ref_store(the_repository), fn, cb_data);
2217 }
2218
2219 int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
2220                                      const char *refname,
2221                                      each_reflog_ent_fn fn,
2222                                      void *cb_data)
2223 {
2224         return refs->be->for_each_reflog_ent_reverse(refs, refname,
2225                                                      fn, cb_data);
2226 }
2227
2228 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
2229                                 void *cb_data)
2230 {
2231         return refs_for_each_reflog_ent_reverse(get_main_ref_store(the_repository),
2232                                                 refname, fn, cb_data);
2233 }
2234
2235 int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
2236                              each_reflog_ent_fn fn, void *cb_data)
2237 {
2238         return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
2239 }
2240
2241 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
2242                         void *cb_data)
2243 {
2244         return refs_for_each_reflog_ent(get_main_ref_store(the_repository), refname,
2245                                         fn, cb_data);
2246 }
2247
2248 int refs_reflog_exists(struct ref_store *refs, const char *refname)
2249 {
2250         return refs->be->reflog_exists(refs, refname);
2251 }
2252
2253 int reflog_exists(const char *refname)
2254 {
2255         return refs_reflog_exists(get_main_ref_store(the_repository), refname);
2256 }
2257
2258 int refs_create_reflog(struct ref_store *refs, const char *refname,
2259                        int force_create, struct strbuf *err)
2260 {
2261         return refs->be->create_reflog(refs, refname, force_create, err);
2262 }
2263
2264 int safe_create_reflog(const char *refname, int force_create,
2265                        struct strbuf *err)
2266 {
2267         return refs_create_reflog(get_main_ref_store(the_repository), refname,
2268                                   force_create, err);
2269 }
2270
2271 int refs_delete_reflog(struct ref_store *refs, const char *refname)
2272 {
2273         return refs->be->delete_reflog(refs, refname);
2274 }
2275
2276 int delete_reflog(const char *refname)
2277 {
2278         return refs_delete_reflog(get_main_ref_store(the_repository), refname);
2279 }
2280
2281 int refs_reflog_expire(struct ref_store *refs,
2282                        const char *refname, const struct object_id *oid,
2283                        unsigned int flags,
2284                        reflog_expiry_prepare_fn prepare_fn,
2285                        reflog_expiry_should_prune_fn should_prune_fn,
2286                        reflog_expiry_cleanup_fn cleanup_fn,
2287                        void *policy_cb_data)
2288 {
2289         return refs->be->reflog_expire(refs, refname, oid, flags,
2290                                        prepare_fn, should_prune_fn,
2291                                        cleanup_fn, policy_cb_data);
2292 }
2293
2294 int reflog_expire(const char *refname, const struct object_id *oid,
2295                   unsigned int flags,
2296                   reflog_expiry_prepare_fn prepare_fn,
2297                   reflog_expiry_should_prune_fn should_prune_fn,
2298                   reflog_expiry_cleanup_fn cleanup_fn,
2299                   void *policy_cb_data)
2300 {
2301         return refs_reflog_expire(get_main_ref_store(the_repository),
2302                                   refname, oid, flags,
2303                                   prepare_fn, should_prune_fn,
2304                                   cleanup_fn, policy_cb_data);
2305 }
2306
2307 int initial_ref_transaction_commit(struct ref_transaction *transaction,
2308                                    struct strbuf *err)
2309 {
2310         struct ref_store *refs = transaction->ref_store;
2311
2312         return refs->be->initial_transaction_commit(refs, transaction, err);
2313 }
2314
2315 int refs_delete_refs(struct ref_store *refs, const char *msg,
2316                      struct string_list *refnames, unsigned int flags)
2317 {
2318         return refs->be->delete_refs(refs, msg, refnames, flags);
2319 }
2320
2321 int delete_refs(const char *msg, struct string_list *refnames,
2322                 unsigned int flags)
2323 {
2324         return refs_delete_refs(get_main_ref_store(the_repository), msg, refnames, flags);
2325 }
2326
2327 int refs_rename_ref(struct ref_store *refs, const char *oldref,
2328                     const char *newref, const char *logmsg)
2329 {
2330         return refs->be->rename_ref(refs, oldref, newref, logmsg);
2331 }
2332
2333 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
2334 {
2335         return refs_rename_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
2336 }
2337
2338 int refs_copy_existing_ref(struct ref_store *refs, const char *oldref,
2339                     const char *newref, const char *logmsg)
2340 {
2341         return refs->be->copy_ref(refs, oldref, newref, logmsg);
2342 }
2343
2344 int copy_existing_ref(const char *oldref, const char *newref, const char *logmsg)
2345 {
2346         return refs_copy_existing_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
2347 }