Merge branch 'jk/fast-export-anonym-alt'
[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 "run-command.h"
13 #include "object-store.h"
14 #include "object.h"
15 #include "tag.h"
16 #include "submodule.h"
17 #include "worktree.h"
18 #include "argv-array.h"
19 #include "repository.h"
20 #include "sigchain.h"
21
22 /*
23  * List of all available backends
24  */
25 static struct ref_storage_be *refs_backends = &refs_be_files;
26
27 static struct ref_storage_be *find_ref_storage_backend(const char *name)
28 {
29         struct ref_storage_be *be;
30         for (be = refs_backends; be; be = be->next)
31                 if (!strcmp(be->name, name))
32                         return be;
33         return NULL;
34 }
35
36 int ref_storage_backend_exists(const char *name)
37 {
38         return find_ref_storage_backend(name) != NULL;
39 }
40
41 /*
42  * How to handle various characters in refnames:
43  * 0: An acceptable character for refs
44  * 1: End-of-component
45  * 2: ., look for a preceding . to reject .. in refs
46  * 3: {, look for a preceding @ to reject @{ in refs
47  * 4: A bad character: ASCII control characters, and
48  *    ":", "?", "[", "\", "^", "~", SP, or TAB
49  * 5: *, reject unless REFNAME_REFSPEC_PATTERN is set
50  */
51 static unsigned char refname_disposition[256] = {
52         1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
53         4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
54         4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 1,
55         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
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, 4, 4, 0, 4, 0,
58         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
59         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
60 };
61
62 /*
63  * Try to read one refname component from the front of refname.
64  * Return the length of the component found, or -1 if the component is
65  * not legal.  It is legal if it is something reasonable to have under
66  * ".git/refs/"; We do not like it if:
67  *
68  * - it begins with ".", or
69  * - it has double dots "..", or
70  * - it has ASCII control characters, or
71  * - it has ":", "?", "[", "\", "^", "~", SP, or TAB anywhere, or
72  * - it has "*" anywhere unless REFNAME_REFSPEC_PATTERN is set, or
73  * - it ends with a "/", or
74  * - it ends with ".lock", or
75  * - it contains a "@{" portion
76  *
77  * When sanitized is not NULL, instead of rejecting the input refname
78  * as an error, try to come up with a usable replacement for the input
79  * refname in it.
80  */
81 static int check_refname_component(const char *refname, int *flags,
82                                    struct strbuf *sanitized)
83 {
84         const char *cp;
85         char last = '\0';
86         size_t component_start = 0; /* garbage - not a reasonable initial value */
87
88         if (sanitized)
89                 component_start = sanitized->len;
90
91         for (cp = refname; ; cp++) {
92                 int ch = *cp & 255;
93                 unsigned char disp = refname_disposition[ch];
94
95                 if (sanitized && disp != 1)
96                         strbuf_addch(sanitized, ch);
97
98                 switch (disp) {
99                 case 1:
100                         goto out;
101                 case 2:
102                         if (last == '.') { /* Refname contains "..". */
103                                 if (sanitized)
104                                         /* collapse ".." to single "." */
105                                         strbuf_setlen(sanitized, sanitized->len - 1);
106                                 else
107                                         return -1;
108                         }
109                         break;
110                 case 3:
111                         if (last == '@') { /* Refname contains "@{". */
112                                 if (sanitized)
113                                         sanitized->buf[sanitized->len-1] = '-';
114                                 else
115                                         return -1;
116                         }
117                         break;
118                 case 4:
119                         /* forbidden char */
120                         if (sanitized)
121                                 sanitized->buf[sanitized->len-1] = '-';
122                         else
123                                 return -1;
124                         break;
125                 case 5:
126                         if (!(*flags & REFNAME_REFSPEC_PATTERN)) {
127                                 /* refspec can't be a pattern */
128                                 if (sanitized)
129                                         sanitized->buf[sanitized->len-1] = '-';
130                                 else
131                                         return -1;
132                         }
133
134                         /*
135                          * Unset the pattern flag so that we only accept
136                          * a single asterisk for one side of refspec.
137                          */
138                         *flags &= ~ REFNAME_REFSPEC_PATTERN;
139                         break;
140                 }
141                 last = ch;
142         }
143 out:
144         if (cp == refname)
145                 return 0; /* Component has zero length. */
146
147         if (refname[0] == '.') { /* Component starts with '.'. */
148                 if (sanitized)
149                         sanitized->buf[component_start] = '-';
150                 else
151                         return -1;
152         }
153         if (cp - refname >= LOCK_SUFFIX_LEN &&
154             !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN)) {
155                 if (!sanitized)
156                         return -1;
157                 /* Refname ends with ".lock". */
158                 while (strbuf_strip_suffix(sanitized, LOCK_SUFFIX)) {
159                         /* try again in case we have .lock.lock */
160                 }
161         }
162         return cp - refname;
163 }
164
165 static int check_or_sanitize_refname(const char *refname, int flags,
166                                      struct strbuf *sanitized)
167 {
168         int component_len, component_count = 0;
169
170         if (!strcmp(refname, "@")) {
171                 /* Refname is a single character '@'. */
172                 if (sanitized)
173                         strbuf_addch(sanitized, '-');
174                 else
175                         return -1;
176         }
177
178         while (1) {
179                 if (sanitized && sanitized->len)
180                         strbuf_complete(sanitized, '/');
181
182                 /* We are at the start of a path component. */
183                 component_len = check_refname_component(refname, &flags,
184                                                         sanitized);
185                 if (sanitized && component_len == 0)
186                         ; /* OK, omit empty component */
187                 else if (component_len <= 0)
188                         return -1;
189
190                 component_count++;
191                 if (refname[component_len] == '\0')
192                         break;
193                 /* Skip to next component. */
194                 refname += component_len + 1;
195         }
196
197         if (refname[component_len - 1] == '.') {
198                 /* Refname ends with '.'. */
199                 if (sanitized)
200                         ; /* omit ending dot */
201                 else
202                         return -1;
203         }
204         if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
205                 return -1; /* Refname has only one component. */
206         return 0;
207 }
208
209 int check_refname_format(const char *refname, int flags)
210 {
211         return check_or_sanitize_refname(refname, flags, NULL);
212 }
213
214 void sanitize_refname_component(const char *refname, struct strbuf *out)
215 {
216         if (check_or_sanitize_refname(refname, REFNAME_ALLOW_ONELEVEL, out))
217                 BUG("sanitizing refname '%s' check returned error", refname);
218 }
219
220 int refname_is_safe(const char *refname)
221 {
222         const char *rest;
223
224         if (skip_prefix(refname, "refs/", &rest)) {
225                 char *buf;
226                 int result;
227                 size_t restlen = strlen(rest);
228
229                 /* rest must not be empty, or start or end with "/" */
230                 if (!restlen || *rest == '/' || rest[restlen - 1] == '/')
231                         return 0;
232
233                 /*
234                  * Does the refname try to escape refs/?
235                  * For example: refs/foo/../bar is safe but refs/foo/../../bar
236                  * is not.
237                  */
238                 buf = xmallocz(restlen);
239                 result = !normalize_path_copy(buf, rest) && !strcmp(buf, rest);
240                 free(buf);
241                 return result;
242         }
243
244         do {
245                 if (!isupper(*refname) && *refname != '_')
246                         return 0;
247                 refname++;
248         } while (*refname);
249         return 1;
250 }
251
252 /*
253  * Return true if refname, which has the specified oid and flags, can
254  * be resolved to an object in the database. If the referred-to object
255  * does not exist, emit a warning and return false.
256  */
257 int ref_resolves_to_object(const char *refname,
258                            const struct object_id *oid,
259                            unsigned int flags)
260 {
261         if (flags & REF_ISBROKEN)
262                 return 0;
263         if (!has_object_file(oid)) {
264                 error(_("%s does not point to a valid object!"), refname);
265                 return 0;
266         }
267         return 1;
268 }
269
270 char *refs_resolve_refdup(struct ref_store *refs,
271                           const char *refname, int resolve_flags,
272                           struct object_id *oid, int *flags)
273 {
274         const char *result;
275
276         result = refs_resolve_ref_unsafe(refs, refname, resolve_flags,
277                                          oid, flags);
278         return xstrdup_or_null(result);
279 }
280
281 char *resolve_refdup(const char *refname, int resolve_flags,
282                      struct object_id *oid, int *flags)
283 {
284         return refs_resolve_refdup(get_main_ref_store(the_repository),
285                                    refname, resolve_flags,
286                                    oid, flags);
287 }
288
289 /* The argument to filter_refs */
290 struct ref_filter {
291         const char *pattern;
292         const char *prefix;
293         each_ref_fn *fn;
294         void *cb_data;
295 };
296
297 int refs_read_ref_full(struct ref_store *refs, const char *refname,
298                        int resolve_flags, struct object_id *oid, int *flags)
299 {
300         if (refs_resolve_ref_unsafe(refs, refname, resolve_flags, oid, flags))
301                 return 0;
302         return -1;
303 }
304
305 int read_ref_full(const char *refname, int resolve_flags, struct object_id *oid, int *flags)
306 {
307         return refs_read_ref_full(get_main_ref_store(the_repository), refname,
308                                   resolve_flags, oid, flags);
309 }
310
311 int read_ref(const char *refname, struct object_id *oid)
312 {
313         return read_ref_full(refname, RESOLVE_REF_READING, oid, NULL);
314 }
315
316 static int refs_ref_exists(struct ref_store *refs, const char *refname)
317 {
318         return !!refs_resolve_ref_unsafe(refs, refname, RESOLVE_REF_READING, NULL, NULL);
319 }
320
321 int ref_exists(const char *refname)
322 {
323         return refs_ref_exists(get_main_ref_store(the_repository), refname);
324 }
325
326 static int filter_refs(const char *refname, const struct object_id *oid,
327                            int flags, void *data)
328 {
329         struct ref_filter *filter = (struct ref_filter *)data;
330
331         if (wildmatch(filter->pattern, refname, 0))
332                 return 0;
333         if (filter->prefix)
334                 skip_prefix(refname, filter->prefix, &refname);
335         return filter->fn(refname, oid, flags, filter->cb_data);
336 }
337
338 enum peel_status peel_object(const struct object_id *name, struct object_id *oid)
339 {
340         struct object *o = lookup_unknown_object(name);
341
342         if (o->type == OBJ_NONE) {
343                 int type = oid_object_info(the_repository, name, NULL);
344                 if (type < 0 || !object_as_type(o, type, 0))
345                         return PEEL_INVALID;
346         }
347
348         if (o->type != OBJ_TAG)
349                 return PEEL_NON_TAG;
350
351         o = deref_tag_noverify(o);
352         if (!o)
353                 return PEEL_INVALID;
354
355         oidcpy(oid, &o->oid);
356         return PEEL_PEELED;
357 }
358
359 struct warn_if_dangling_data {
360         FILE *fp;
361         const char *refname;
362         const struct string_list *refnames;
363         const char *msg_fmt;
364 };
365
366 static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
367                                    int flags, void *cb_data)
368 {
369         struct warn_if_dangling_data *d = cb_data;
370         const char *resolves_to;
371
372         if (!(flags & REF_ISSYMREF))
373                 return 0;
374
375         resolves_to = resolve_ref_unsafe(refname, 0, NULL, NULL);
376         if (!resolves_to
377             || (d->refname
378                 ? strcmp(resolves_to, d->refname)
379                 : !string_list_has_string(d->refnames, resolves_to))) {
380                 return 0;
381         }
382
383         fprintf(d->fp, d->msg_fmt, refname);
384         fputc('\n', d->fp);
385         return 0;
386 }
387
388 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
389 {
390         struct warn_if_dangling_data data;
391
392         data.fp = fp;
393         data.refname = refname;
394         data.refnames = NULL;
395         data.msg_fmt = msg_fmt;
396         for_each_rawref(warn_if_dangling_symref, &data);
397 }
398
399 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
400 {
401         struct warn_if_dangling_data data;
402
403         data.fp = fp;
404         data.refname = NULL;
405         data.refnames = refnames;
406         data.msg_fmt = msg_fmt;
407         for_each_rawref(warn_if_dangling_symref, &data);
408 }
409
410 int refs_for_each_tag_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
411 {
412         return refs_for_each_ref_in(refs, "refs/tags/", fn, cb_data);
413 }
414
415 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
416 {
417         return refs_for_each_tag_ref(get_main_ref_store(the_repository), fn, cb_data);
418 }
419
420 int refs_for_each_branch_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
421 {
422         return refs_for_each_ref_in(refs, "refs/heads/", fn, cb_data);
423 }
424
425 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
426 {
427         return refs_for_each_branch_ref(get_main_ref_store(the_repository), fn, cb_data);
428 }
429
430 int refs_for_each_remote_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
431 {
432         return refs_for_each_ref_in(refs, "refs/remotes/", fn, cb_data);
433 }
434
435 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
436 {
437         return refs_for_each_remote_ref(get_main_ref_store(the_repository), fn, cb_data);
438 }
439
440 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
441 {
442         struct strbuf buf = STRBUF_INIT;
443         int ret = 0;
444         struct object_id oid;
445         int flag;
446
447         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
448         if (!read_ref_full(buf.buf, RESOLVE_REF_READING, &oid, &flag))
449                 ret = fn(buf.buf, &oid, flag, cb_data);
450         strbuf_release(&buf);
451
452         return ret;
453 }
454
455 void normalize_glob_ref(struct string_list_item *item, const char *prefix,
456                         const char *pattern)
457 {
458         struct strbuf normalized_pattern = STRBUF_INIT;
459
460         if (*pattern == '/')
461                 BUG("pattern must not start with '/'");
462
463         if (prefix) {
464                 strbuf_addstr(&normalized_pattern, prefix);
465         }
466         else if (!starts_with(pattern, "refs/"))
467                 strbuf_addstr(&normalized_pattern, "refs/");
468         strbuf_addstr(&normalized_pattern, pattern);
469         strbuf_strip_suffix(&normalized_pattern, "/");
470
471         item->string = strbuf_detach(&normalized_pattern, NULL);
472         item->util = has_glob_specials(pattern) ? NULL : item->string;
473         strbuf_release(&normalized_pattern);
474 }
475
476 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
477         const char *prefix, void *cb_data)
478 {
479         struct strbuf real_pattern = STRBUF_INIT;
480         struct ref_filter filter;
481         int ret;
482
483         if (!prefix && !starts_with(pattern, "refs/"))
484                 strbuf_addstr(&real_pattern, "refs/");
485         else if (prefix)
486                 strbuf_addstr(&real_pattern, prefix);
487         strbuf_addstr(&real_pattern, pattern);
488
489         if (!has_glob_specials(pattern)) {
490                 /* Append implied '/' '*' if not present. */
491                 strbuf_complete(&real_pattern, '/');
492                 /* No need to check for '*', there is none. */
493                 strbuf_addch(&real_pattern, '*');
494         }
495
496         filter.pattern = real_pattern.buf;
497         filter.prefix = prefix;
498         filter.fn = fn;
499         filter.cb_data = cb_data;
500         ret = for_each_ref(filter_refs, &filter);
501
502         strbuf_release(&real_pattern);
503         return ret;
504 }
505
506 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
507 {
508         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
509 }
510
511 const char *prettify_refname(const char *name)
512 {
513         if (skip_prefix(name, "refs/heads/", &name) ||
514             skip_prefix(name, "refs/tags/", &name) ||
515             skip_prefix(name, "refs/remotes/", &name))
516                 ; /* nothing */
517         return name;
518 }
519
520 static const char *ref_rev_parse_rules[] = {
521         "%.*s",
522         "refs/%.*s",
523         "refs/tags/%.*s",
524         "refs/heads/%.*s",
525         "refs/remotes/%.*s",
526         "refs/remotes/%.*s/HEAD",
527         NULL
528 };
529
530 #define NUM_REV_PARSE_RULES (ARRAY_SIZE(ref_rev_parse_rules) - 1)
531
532 /*
533  * Is it possible that the caller meant full_name with abbrev_name?
534  * If so return a non-zero value to signal "yes"; the magnitude of
535  * the returned value gives the precedence used for disambiguation.
536  *
537  * If abbrev_name cannot mean full_name, return 0.
538  */
539 int refname_match(const char *abbrev_name, const char *full_name)
540 {
541         const char **p;
542         const int abbrev_name_len = strlen(abbrev_name);
543         const int num_rules = NUM_REV_PARSE_RULES;
544
545         for (p = ref_rev_parse_rules; *p; p++)
546                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name)))
547                         return &ref_rev_parse_rules[num_rules] - p;
548
549         return 0;
550 }
551
552 /*
553  * Given a 'prefix' expand it by the rules in 'ref_rev_parse_rules' and add
554  * the results to 'prefixes'
555  */
556 void expand_ref_prefix(struct argv_array *prefixes, const char *prefix)
557 {
558         const char **p;
559         int len = strlen(prefix);
560
561         for (p = ref_rev_parse_rules; *p; p++)
562                 argv_array_pushf(prefixes, *p, len, prefix);
563 }
564
565 char *repo_default_branch_name(struct repository *r)
566 {
567         const char *config_key = "init.defaultbranch";
568         const char *config_display_key = "init.defaultBranch";
569         char *ret = NULL, *full_ref;
570
571         if (repo_config_get_string(r, config_key, &ret) < 0)
572                 die(_("could not retrieve `%s`"), config_display_key);
573
574         if (!ret)
575                 ret = xstrdup("master");
576
577         full_ref = xstrfmt("refs/heads/%s", ret);
578         if (check_refname_format(full_ref, 0))
579                 die(_("invalid branch name: %s = %s"), config_display_key, ret);
580         free(full_ref);
581
582         return ret;
583 }
584
585 const char *git_default_branch_name(void)
586 {
587         static char *ret;
588
589         if (!ret)
590                 ret = repo_default_branch_name(the_repository);
591
592         return ret;
593 }
594
595 /*
596  * *string and *len will only be substituted, and *string returned (for
597  * later free()ing) if the string passed in is a magic short-hand form
598  * to name a branch.
599  */
600 static char *substitute_branch_name(struct repository *r,
601                                     const char **string, int *len)
602 {
603         struct strbuf buf = STRBUF_INIT;
604         int ret = repo_interpret_branch_name(r, *string, *len, &buf, 0);
605
606         if (ret == *len) {
607                 size_t size;
608                 *string = strbuf_detach(&buf, &size);
609                 *len = size;
610                 return (char *)*string;
611         }
612
613         return NULL;
614 }
615
616 int repo_dwim_ref(struct repository *r, const char *str, int len,
617                   struct object_id *oid, char **ref)
618 {
619         char *last_branch = substitute_branch_name(r, &str, &len);
620         int   refs_found  = expand_ref(r, str, len, oid, ref);
621         free(last_branch);
622         return refs_found;
623 }
624
625 int dwim_ref(const char *str, int len, struct object_id *oid, char **ref)
626 {
627         return repo_dwim_ref(the_repository, str, len, oid, ref);
628 }
629
630 int expand_ref(struct repository *repo, const char *str, int len,
631                struct object_id *oid, char **ref)
632 {
633         const char **p, *r;
634         int refs_found = 0;
635         struct strbuf fullref = STRBUF_INIT;
636
637         *ref = NULL;
638         for (p = ref_rev_parse_rules; *p; p++) {
639                 struct object_id oid_from_ref;
640                 struct object_id *this_result;
641                 int flag;
642
643                 this_result = refs_found ? &oid_from_ref : oid;
644                 strbuf_reset(&fullref);
645                 strbuf_addf(&fullref, *p, len, str);
646                 r = refs_resolve_ref_unsafe(get_main_ref_store(repo),
647                                             fullref.buf, RESOLVE_REF_READING,
648                                             this_result, &flag);
649                 if (r) {
650                         if (!refs_found++)
651                                 *ref = xstrdup(r);
652                         if (!warn_ambiguous_refs)
653                                 break;
654                 } else if ((flag & REF_ISSYMREF) && strcmp(fullref.buf, "HEAD")) {
655                         warning(_("ignoring dangling symref %s"), fullref.buf);
656                 } else if ((flag & REF_ISBROKEN) && strchr(fullref.buf, '/')) {
657                         warning(_("ignoring broken ref %s"), fullref.buf);
658                 }
659         }
660         strbuf_release(&fullref);
661         return refs_found;
662 }
663
664 int repo_dwim_log(struct repository *r, const char *str, int len,
665                   struct object_id *oid, char **log)
666 {
667         struct ref_store *refs = get_main_ref_store(r);
668         char *last_branch = substitute_branch_name(r, &str, &len);
669         const char **p;
670         int logs_found = 0;
671         struct strbuf path = STRBUF_INIT;
672
673         *log = NULL;
674         for (p = ref_rev_parse_rules; *p; p++) {
675                 struct object_id hash;
676                 const char *ref, *it;
677
678                 strbuf_reset(&path);
679                 strbuf_addf(&path, *p, len, str);
680                 ref = refs_resolve_ref_unsafe(refs, path.buf,
681                                               RESOLVE_REF_READING,
682                                               &hash, NULL);
683                 if (!ref)
684                         continue;
685                 if (refs_reflog_exists(refs, path.buf))
686                         it = path.buf;
687                 else if (strcmp(ref, path.buf) &&
688                          refs_reflog_exists(refs, ref))
689                         it = ref;
690                 else
691                         continue;
692                 if (!logs_found++) {
693                         *log = xstrdup(it);
694                         oidcpy(oid, &hash);
695                 }
696                 if (!warn_ambiguous_refs)
697                         break;
698         }
699         strbuf_release(&path);
700         free(last_branch);
701         return logs_found;
702 }
703
704 int dwim_log(const char *str, int len, struct object_id *oid, char **log)
705 {
706         return repo_dwim_log(the_repository, str, len, oid, log);
707 }
708
709 static int is_per_worktree_ref(const char *refname)
710 {
711         return !strcmp(refname, "HEAD") ||
712                 starts_with(refname, "refs/worktree/") ||
713                 starts_with(refname, "refs/bisect/") ||
714                 starts_with(refname, "refs/rewritten/");
715 }
716
717 static int is_pseudoref_syntax(const char *refname)
718 {
719         const char *c;
720
721         for (c = refname; *c; c++) {
722                 if (!isupper(*c) && *c != '-' && *c != '_')
723                         return 0;
724         }
725
726         return 1;
727 }
728
729 static int is_main_pseudoref_syntax(const char *refname)
730 {
731         return skip_prefix(refname, "main-worktree/", &refname) &&
732                 *refname &&
733                 is_pseudoref_syntax(refname);
734 }
735
736 static int is_other_pseudoref_syntax(const char *refname)
737 {
738         if (!skip_prefix(refname, "worktrees/", &refname))
739                 return 0;
740         refname = strchr(refname, '/');
741         if (!refname || !refname[1])
742                 return 0;
743         return is_pseudoref_syntax(refname + 1);
744 }
745
746 enum ref_type ref_type(const char *refname)
747 {
748         if (is_per_worktree_ref(refname))
749                 return REF_TYPE_PER_WORKTREE;
750         if (is_pseudoref_syntax(refname))
751                 return REF_TYPE_PSEUDOREF;
752         if (is_main_pseudoref_syntax(refname))
753                 return REF_TYPE_MAIN_PSEUDOREF;
754         if (is_other_pseudoref_syntax(refname))
755                 return REF_TYPE_OTHER_PSEUDOREF;
756         return REF_TYPE_NORMAL;
757 }
758
759 long get_files_ref_lock_timeout_ms(void)
760 {
761         static int configured = 0;
762
763         /* The default timeout is 100 ms: */
764         static int timeout_ms = 100;
765
766         if (!configured) {
767                 git_config_get_int("core.filesreflocktimeout", &timeout_ms);
768                 configured = 1;
769         }
770
771         return timeout_ms;
772 }
773
774 static int write_pseudoref(const char *pseudoref, const struct object_id *oid,
775                            const struct object_id *old_oid, struct strbuf *err)
776 {
777         const char *filename;
778         int fd;
779         struct lock_file lock = LOCK_INIT;
780         struct strbuf buf = STRBUF_INIT;
781         int ret = -1;
782
783         if (!oid)
784                 return 0;
785
786         strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
787
788         filename = git_path("%s", pseudoref);
789         fd = hold_lock_file_for_update_timeout(&lock, filename, 0,
790                                                get_files_ref_lock_timeout_ms());
791         if (fd < 0) {
792                 strbuf_addf(err, _("could not open '%s' for writing: %s"),
793                             filename, strerror(errno));
794                 goto done;
795         }
796
797         if (old_oid) {
798                 struct object_id actual_old_oid;
799
800                 if (read_ref(pseudoref, &actual_old_oid)) {
801                         if (!is_null_oid(old_oid)) {
802                                 strbuf_addf(err, _("could not read ref '%s'"),
803                                             pseudoref);
804                                 rollback_lock_file(&lock);
805                                 goto done;
806                         }
807                 } else if (is_null_oid(old_oid)) {
808                         strbuf_addf(err, _("ref '%s' already exists"),
809                                     pseudoref);
810                         rollback_lock_file(&lock);
811                         goto done;
812                 } else if (!oideq(&actual_old_oid, old_oid)) {
813                         strbuf_addf(err, _("unexpected object ID when writing '%s'"),
814                                     pseudoref);
815                         rollback_lock_file(&lock);
816                         goto done;
817                 }
818         }
819
820         if (write_in_full(fd, buf.buf, buf.len) < 0) {
821                 strbuf_addf(err, _("could not write to '%s'"), filename);
822                 rollback_lock_file(&lock);
823                 goto done;
824         }
825
826         commit_lock_file(&lock);
827         ret = 0;
828 done:
829         strbuf_release(&buf);
830         return ret;
831 }
832
833 static int delete_pseudoref(const char *pseudoref, const struct object_id *old_oid)
834 {
835         const char *filename;
836
837         filename = git_path("%s", pseudoref);
838
839         if (old_oid && !is_null_oid(old_oid)) {
840                 struct lock_file lock = LOCK_INIT;
841                 int fd;
842                 struct object_id actual_old_oid;
843
844                 fd = hold_lock_file_for_update_timeout(
845                                 &lock, filename, 0,
846                                 get_files_ref_lock_timeout_ms());
847                 if (fd < 0) {
848                         error_errno(_("could not open '%s' for writing"),
849                                     filename);
850                         return -1;
851                 }
852                 if (read_ref(pseudoref, &actual_old_oid))
853                         die(_("could not read ref '%s'"), pseudoref);
854                 if (!oideq(&actual_old_oid, old_oid)) {
855                         error(_("unexpected object ID when deleting '%s'"),
856                               pseudoref);
857                         rollback_lock_file(&lock);
858                         return -1;
859                 }
860
861                 unlink(filename);
862                 rollback_lock_file(&lock);
863         } else {
864                 unlink(filename);
865         }
866
867         return 0;
868 }
869
870 int refs_delete_ref(struct ref_store *refs, const char *msg,
871                     const char *refname,
872                     const struct object_id *old_oid,
873                     unsigned int flags)
874 {
875         struct ref_transaction *transaction;
876         struct strbuf err = STRBUF_INIT;
877
878         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
879                 assert(refs == get_main_ref_store(the_repository));
880                 return delete_pseudoref(refname, old_oid);
881         }
882
883         transaction = ref_store_transaction_begin(refs, &err);
884         if (!transaction ||
885             ref_transaction_delete(transaction, refname, old_oid,
886                                    flags, msg, &err) ||
887             ref_transaction_commit(transaction, &err)) {
888                 error("%s", err.buf);
889                 ref_transaction_free(transaction);
890                 strbuf_release(&err);
891                 return 1;
892         }
893         ref_transaction_free(transaction);
894         strbuf_release(&err);
895         return 0;
896 }
897
898 int delete_ref(const char *msg, const char *refname,
899                const struct object_id *old_oid, unsigned int flags)
900 {
901         return refs_delete_ref(get_main_ref_store(the_repository), msg, refname,
902                                old_oid, flags);
903 }
904
905 void copy_reflog_msg(struct strbuf *sb, const char *msg)
906 {
907         char c;
908         int wasspace = 1;
909
910         strbuf_addch(sb, '\t');
911         while ((c = *msg++)) {
912                 if (wasspace && isspace(c))
913                         continue;
914                 wasspace = isspace(c);
915                 if (wasspace)
916                         c = ' ';
917                 strbuf_addch(sb, c);
918         }
919         strbuf_rtrim(sb);
920 }
921
922 int should_autocreate_reflog(const char *refname)
923 {
924         switch (log_all_ref_updates) {
925         case LOG_REFS_ALWAYS:
926                 return 1;
927         case LOG_REFS_NORMAL:
928                 return starts_with(refname, "refs/heads/") ||
929                         starts_with(refname, "refs/remotes/") ||
930                         starts_with(refname, "refs/notes/") ||
931                         !strcmp(refname, "HEAD");
932         default:
933                 return 0;
934         }
935 }
936
937 int is_branch(const char *refname)
938 {
939         return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
940 }
941
942 struct read_ref_at_cb {
943         const char *refname;
944         timestamp_t at_time;
945         int cnt;
946         int reccnt;
947         struct object_id *oid;
948         int found_it;
949
950         struct object_id ooid;
951         struct object_id noid;
952         int tz;
953         timestamp_t date;
954         char **msg;
955         timestamp_t *cutoff_time;
956         int *cutoff_tz;
957         int *cutoff_cnt;
958 };
959
960 static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
961                 const char *email, timestamp_t timestamp, int tz,
962                 const char *message, void *cb_data)
963 {
964         struct read_ref_at_cb *cb = cb_data;
965
966         cb->reccnt++;
967         cb->tz = tz;
968         cb->date = timestamp;
969
970         if (timestamp <= cb->at_time || cb->cnt == 0) {
971                 if (cb->msg)
972                         *cb->msg = xstrdup(message);
973                 if (cb->cutoff_time)
974                         *cb->cutoff_time = timestamp;
975                 if (cb->cutoff_tz)
976                         *cb->cutoff_tz = tz;
977                 if (cb->cutoff_cnt)
978                         *cb->cutoff_cnt = cb->reccnt - 1;
979                 /*
980                  * we have not yet updated cb->[n|o]oid so they still
981                  * hold the values for the previous record.
982                  */
983                 if (!is_null_oid(&cb->ooid)) {
984                         oidcpy(cb->oid, noid);
985                         if (!oideq(&cb->ooid, noid))
986                                 warning(_("log for ref %s has gap after %s"),
987                                         cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
988                 }
989                 else if (cb->date == cb->at_time)
990                         oidcpy(cb->oid, noid);
991                 else if (!oideq(noid, cb->oid))
992                         warning(_("log for ref %s unexpectedly ended on %s"),
993                                 cb->refname, show_date(cb->date, cb->tz,
994                                                        DATE_MODE(RFC2822)));
995                 oidcpy(&cb->ooid, ooid);
996                 oidcpy(&cb->noid, noid);
997                 cb->found_it = 1;
998                 return 1;
999         }
1000         oidcpy(&cb->ooid, ooid);
1001         oidcpy(&cb->noid, noid);
1002         if (cb->cnt > 0)
1003                 cb->cnt--;
1004         return 0;
1005 }
1006
1007 static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
1008                                   const char *email, timestamp_t timestamp,
1009                                   int tz, const char *message, void *cb_data)
1010 {
1011         struct read_ref_at_cb *cb = cb_data;
1012
1013         if (cb->msg)
1014                 *cb->msg = xstrdup(message);
1015         if (cb->cutoff_time)
1016                 *cb->cutoff_time = timestamp;
1017         if (cb->cutoff_tz)
1018                 *cb->cutoff_tz = tz;
1019         if (cb->cutoff_cnt)
1020                 *cb->cutoff_cnt = cb->reccnt;
1021         oidcpy(cb->oid, ooid);
1022         if (is_null_oid(cb->oid))
1023                 oidcpy(cb->oid, noid);
1024         /* We just want the first entry */
1025         return 1;
1026 }
1027
1028 int read_ref_at(struct ref_store *refs, const char *refname,
1029                 unsigned int flags, timestamp_t at_time, int cnt,
1030                 struct object_id *oid, char **msg,
1031                 timestamp_t *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
1032 {
1033         struct read_ref_at_cb cb;
1034
1035         memset(&cb, 0, sizeof(cb));
1036         cb.refname = refname;
1037         cb.at_time = at_time;
1038         cb.cnt = cnt;
1039         cb.msg = msg;
1040         cb.cutoff_time = cutoff_time;
1041         cb.cutoff_tz = cutoff_tz;
1042         cb.cutoff_cnt = cutoff_cnt;
1043         cb.oid = oid;
1044
1045         refs_for_each_reflog_ent_reverse(refs, refname, read_ref_at_ent, &cb);
1046
1047         if (!cb.reccnt) {
1048                 if (flags & GET_OID_QUIETLY)
1049                         exit(128);
1050                 else
1051                         die(_("log for %s is empty"), refname);
1052         }
1053         if (cb.found_it)
1054                 return 0;
1055
1056         refs_for_each_reflog_ent(refs, refname, read_ref_at_ent_oldest, &cb);
1057
1058         return 1;
1059 }
1060
1061 struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
1062                                                     struct strbuf *err)
1063 {
1064         struct ref_transaction *tr;
1065         assert(err);
1066
1067         tr = xcalloc(1, sizeof(struct ref_transaction));
1068         tr->ref_store = refs;
1069         return tr;
1070 }
1071
1072 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
1073 {
1074         return ref_store_transaction_begin(get_main_ref_store(the_repository), err);
1075 }
1076
1077 void ref_transaction_free(struct ref_transaction *transaction)
1078 {
1079         size_t i;
1080
1081         if (!transaction)
1082                 return;
1083
1084         switch (transaction->state) {
1085         case REF_TRANSACTION_OPEN:
1086         case REF_TRANSACTION_CLOSED:
1087                 /* OK */
1088                 break;
1089         case REF_TRANSACTION_PREPARED:
1090                 BUG("free called on a prepared reference transaction");
1091                 break;
1092         default:
1093                 BUG("unexpected reference transaction state");
1094                 break;
1095         }
1096
1097         for (i = 0; i < transaction->nr; i++) {
1098                 free(transaction->updates[i]->msg);
1099                 free(transaction->updates[i]);
1100         }
1101         free(transaction->updates);
1102         free(transaction);
1103 }
1104
1105 struct ref_update *ref_transaction_add_update(
1106                 struct ref_transaction *transaction,
1107                 const char *refname, unsigned int flags,
1108                 const struct object_id *new_oid,
1109                 const struct object_id *old_oid,
1110                 const char *msg)
1111 {
1112         struct ref_update *update;
1113
1114         if (transaction->state != REF_TRANSACTION_OPEN)
1115                 BUG("update called for transaction that is not open");
1116
1117         FLEX_ALLOC_STR(update, refname, refname);
1118         ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
1119         transaction->updates[transaction->nr++] = update;
1120
1121         update->flags = flags;
1122
1123         if (flags & REF_HAVE_NEW)
1124                 oidcpy(&update->new_oid, new_oid);
1125         if (flags & REF_HAVE_OLD)
1126                 oidcpy(&update->old_oid, old_oid);
1127         update->msg = xstrdup_or_null(msg);
1128         return update;
1129 }
1130
1131 int ref_transaction_update(struct ref_transaction *transaction,
1132                            const char *refname,
1133                            const struct object_id *new_oid,
1134                            const struct object_id *old_oid,
1135                            unsigned int flags, const char *msg,
1136                            struct strbuf *err)
1137 {
1138         assert(err);
1139
1140         if ((new_oid && !is_null_oid(new_oid)) ?
1141             check_refname_format(refname, REFNAME_ALLOW_ONELEVEL) :
1142             !refname_is_safe(refname)) {
1143                 strbuf_addf(err, _("refusing to update ref with bad name '%s'"),
1144                             refname);
1145                 return -1;
1146         }
1147
1148         if (flags & ~REF_TRANSACTION_UPDATE_ALLOWED_FLAGS)
1149                 BUG("illegal flags 0x%x passed to ref_transaction_update()", flags);
1150
1151         flags |= (new_oid ? REF_HAVE_NEW : 0) | (old_oid ? REF_HAVE_OLD : 0);
1152
1153         ref_transaction_add_update(transaction, refname, flags,
1154                                    new_oid, old_oid, msg);
1155         return 0;
1156 }
1157
1158 int ref_transaction_create(struct ref_transaction *transaction,
1159                            const char *refname,
1160                            const struct object_id *new_oid,
1161                            unsigned int flags, const char *msg,
1162                            struct strbuf *err)
1163 {
1164         if (!new_oid || is_null_oid(new_oid))
1165                 BUG("create called without valid new_oid");
1166         return ref_transaction_update(transaction, refname, new_oid,
1167                                       &null_oid, flags, msg, err);
1168 }
1169
1170 int ref_transaction_delete(struct ref_transaction *transaction,
1171                            const char *refname,
1172                            const struct object_id *old_oid,
1173                            unsigned int flags, const char *msg,
1174                            struct strbuf *err)
1175 {
1176         if (old_oid && is_null_oid(old_oid))
1177                 BUG("delete called with old_oid set to zeros");
1178         return ref_transaction_update(transaction, refname,
1179                                       &null_oid, old_oid,
1180                                       flags, msg, err);
1181 }
1182
1183 int ref_transaction_verify(struct ref_transaction *transaction,
1184                            const char *refname,
1185                            const struct object_id *old_oid,
1186                            unsigned int flags,
1187                            struct strbuf *err)
1188 {
1189         if (!old_oid)
1190                 BUG("verify called with old_oid set to NULL");
1191         return ref_transaction_update(transaction, refname,
1192                                       NULL, old_oid,
1193                                       flags, NULL, err);
1194 }
1195
1196 int refs_update_ref(struct ref_store *refs, const char *msg,
1197                     const char *refname, const struct object_id *new_oid,
1198                     const struct object_id *old_oid, unsigned int flags,
1199                     enum action_on_err onerr)
1200 {
1201         struct ref_transaction *t = NULL;
1202         struct strbuf err = STRBUF_INIT;
1203         int ret = 0;
1204
1205         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
1206                 assert(refs == get_main_ref_store(the_repository));
1207                 ret = write_pseudoref(refname, new_oid, old_oid, &err);
1208         } else {
1209                 t = ref_store_transaction_begin(refs, &err);
1210                 if (!t ||
1211                     ref_transaction_update(t, refname, new_oid, old_oid,
1212                                            flags, msg, &err) ||
1213                     ref_transaction_commit(t, &err)) {
1214                         ret = 1;
1215                         ref_transaction_free(t);
1216                 }
1217         }
1218         if (ret) {
1219                 const char *str = _("update_ref failed for ref '%s': %s");
1220
1221                 switch (onerr) {
1222                 case UPDATE_REFS_MSG_ON_ERR:
1223                         error(str, refname, err.buf);
1224                         break;
1225                 case UPDATE_REFS_DIE_ON_ERR:
1226                         die(str, refname, err.buf);
1227                         break;
1228                 case UPDATE_REFS_QUIET_ON_ERR:
1229                         break;
1230                 }
1231                 strbuf_release(&err);
1232                 return 1;
1233         }
1234         strbuf_release(&err);
1235         if (t)
1236                 ref_transaction_free(t);
1237         return 0;
1238 }
1239
1240 int update_ref(const char *msg, const char *refname,
1241                const struct object_id *new_oid,
1242                const struct object_id *old_oid,
1243                unsigned int flags, enum action_on_err onerr)
1244 {
1245         return refs_update_ref(get_main_ref_store(the_repository), msg, refname, new_oid,
1246                                old_oid, flags, onerr);
1247 }
1248
1249 char *refs_shorten_unambiguous_ref(struct ref_store *refs,
1250                                    const char *refname, int strict)
1251 {
1252         int i;
1253         static char **scanf_fmts;
1254         static int nr_rules;
1255         char *short_name;
1256         struct strbuf resolved_buf = STRBUF_INIT;
1257
1258         if (!nr_rules) {
1259                 /*
1260                  * Pre-generate scanf formats from ref_rev_parse_rules[].
1261                  * Generate a format suitable for scanf from a
1262                  * ref_rev_parse_rules rule by interpolating "%s" at the
1263                  * location of the "%.*s".
1264                  */
1265                 size_t total_len = 0;
1266                 size_t offset = 0;
1267
1268                 /* the rule list is NULL terminated, count them first */
1269                 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
1270                         /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
1271                         total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
1272
1273                 scanf_fmts = xmalloc(st_add(st_mult(sizeof(char *), nr_rules), total_len));
1274
1275                 offset = 0;
1276                 for (i = 0; i < nr_rules; i++) {
1277                         assert(offset < total_len);
1278                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
1279                         offset += xsnprintf(scanf_fmts[i], total_len - offset,
1280                                             ref_rev_parse_rules[i], 2, "%s") + 1;
1281                 }
1282         }
1283
1284         /* bail out if there are no rules */
1285         if (!nr_rules)
1286                 return xstrdup(refname);
1287
1288         /* buffer for scanf result, at most refname must fit */
1289         short_name = xstrdup(refname);
1290
1291         /* skip first rule, it will always match */
1292         for (i = nr_rules - 1; i > 0 ; --i) {
1293                 int j;
1294                 int rules_to_fail = i;
1295                 int short_name_len;
1296
1297                 if (1 != sscanf(refname, scanf_fmts[i], short_name))
1298                         continue;
1299
1300                 short_name_len = strlen(short_name);
1301
1302                 /*
1303                  * in strict mode, all (except the matched one) rules
1304                  * must fail to resolve to a valid non-ambiguous ref
1305                  */
1306                 if (strict)
1307                         rules_to_fail = nr_rules;
1308
1309                 /*
1310                  * check if the short name resolves to a valid ref,
1311                  * but use only rules prior to the matched one
1312                  */
1313                 for (j = 0; j < rules_to_fail; j++) {
1314                         const char *rule = ref_rev_parse_rules[j];
1315
1316                         /* skip matched rule */
1317                         if (i == j)
1318                                 continue;
1319
1320                         /*
1321                          * the short name is ambiguous, if it resolves
1322                          * (with this previous rule) to a valid ref
1323                          * read_ref() returns 0 on success
1324                          */
1325                         strbuf_reset(&resolved_buf);
1326                         strbuf_addf(&resolved_buf, rule,
1327                                     short_name_len, short_name);
1328                         if (refs_ref_exists(refs, resolved_buf.buf))
1329                                 break;
1330                 }
1331
1332                 /*
1333                  * short name is non-ambiguous if all previous rules
1334                  * haven't resolved to a valid ref
1335                  */
1336                 if (j == rules_to_fail) {
1337                         strbuf_release(&resolved_buf);
1338                         return short_name;
1339                 }
1340         }
1341
1342         strbuf_release(&resolved_buf);
1343         free(short_name);
1344         return xstrdup(refname);
1345 }
1346
1347 char *shorten_unambiguous_ref(const char *refname, int strict)
1348 {
1349         return refs_shorten_unambiguous_ref(get_main_ref_store(the_repository),
1350                                             refname, strict);
1351 }
1352
1353 static struct string_list *hide_refs;
1354
1355 int parse_hide_refs_config(const char *var, const char *value, const char *section)
1356 {
1357         const char *key;
1358         if (!strcmp("transfer.hiderefs", var) ||
1359             (!parse_config_key(var, section, NULL, NULL, &key) &&
1360              !strcmp(key, "hiderefs"))) {
1361                 char *ref;
1362                 int len;
1363
1364                 if (!value)
1365                         return config_error_nonbool(var);
1366                 ref = xstrdup(value);
1367                 len = strlen(ref);
1368                 while (len && ref[len - 1] == '/')
1369                         ref[--len] = '\0';
1370                 if (!hide_refs) {
1371                         hide_refs = xcalloc(1, sizeof(*hide_refs));
1372                         hide_refs->strdup_strings = 1;
1373                 }
1374                 string_list_append(hide_refs, ref);
1375         }
1376         return 0;
1377 }
1378
1379 int ref_is_hidden(const char *refname, const char *refname_full)
1380 {
1381         int i;
1382
1383         if (!hide_refs)
1384                 return 0;
1385         for (i = hide_refs->nr - 1; i >= 0; i--) {
1386                 const char *match = hide_refs->items[i].string;
1387                 const char *subject;
1388                 int neg = 0;
1389                 const char *p;
1390
1391                 if (*match == '!') {
1392                         neg = 1;
1393                         match++;
1394                 }
1395
1396                 if (*match == '^') {
1397                         subject = refname_full;
1398                         match++;
1399                 } else {
1400                         subject = refname;
1401                 }
1402
1403                 /* refname can be NULL when namespaces are used. */
1404                 if (subject &&
1405                     skip_prefix(subject, match, &p) &&
1406                     (!*p || *p == '/'))
1407                         return !neg;
1408         }
1409         return 0;
1410 }
1411
1412 const char *find_descendant_ref(const char *dirname,
1413                                 const struct string_list *extras,
1414                                 const struct string_list *skip)
1415 {
1416         int pos;
1417
1418         if (!extras)
1419                 return NULL;
1420
1421         /*
1422          * Look at the place where dirname would be inserted into
1423          * extras. If there is an entry at that position that starts
1424          * with dirname (remember, dirname includes the trailing
1425          * slash) and is not in skip, then we have a conflict.
1426          */
1427         for (pos = string_list_find_insert_index(extras, dirname, 0);
1428              pos < extras->nr; pos++) {
1429                 const char *extra_refname = extras->items[pos].string;
1430
1431                 if (!starts_with(extra_refname, dirname))
1432                         break;
1433
1434                 if (!skip || !string_list_has_string(skip, extra_refname))
1435                         return extra_refname;
1436         }
1437         return NULL;
1438 }
1439
1440 int refs_rename_ref_available(struct ref_store *refs,
1441                               const char *old_refname,
1442                               const char *new_refname)
1443 {
1444         struct string_list skip = STRING_LIST_INIT_NODUP;
1445         struct strbuf err = STRBUF_INIT;
1446         int ok;
1447
1448         string_list_insert(&skip, old_refname);
1449         ok = !refs_verify_refname_available(refs, new_refname,
1450                                             NULL, &skip, &err);
1451         if (!ok)
1452                 error("%s", err.buf);
1453
1454         string_list_clear(&skip, 0);
1455         strbuf_release(&err);
1456         return ok;
1457 }
1458
1459 int refs_head_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1460 {
1461         struct object_id oid;
1462         int flag;
1463
1464         if (!refs_read_ref_full(refs, "HEAD", RESOLVE_REF_READING,
1465                                 &oid, &flag))
1466                 return fn("HEAD", &oid, flag, cb_data);
1467
1468         return 0;
1469 }
1470
1471 int head_ref(each_ref_fn fn, void *cb_data)
1472 {
1473         return refs_head_ref(get_main_ref_store(the_repository), fn, cb_data);
1474 }
1475
1476 struct ref_iterator *refs_ref_iterator_begin(
1477                 struct ref_store *refs,
1478                 const char *prefix, int trim, int flags)
1479 {
1480         struct ref_iterator *iter;
1481
1482         if (ref_paranoia < 0)
1483                 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1484         if (ref_paranoia)
1485                 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1486
1487         iter = refs->be->iterator_begin(refs, prefix, flags);
1488
1489         /*
1490          * `iterator_begin()` already takes care of prefix, but we
1491          * might need to do some trimming:
1492          */
1493         if (trim)
1494                 iter = prefix_ref_iterator_begin(iter, "", trim);
1495
1496         /* Sanity check for subclasses: */
1497         if (!iter->ordered)
1498                 BUG("reference iterator is not ordered");
1499
1500         return iter;
1501 }
1502
1503 /*
1504  * Call fn for each reference in the specified submodule for which the
1505  * refname begins with prefix. If trim is non-zero, then trim that
1506  * many characters off the beginning of each refname before passing
1507  * the refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to
1508  * include broken references in the iteration. If fn ever returns a
1509  * non-zero value, stop the iteration and return that value;
1510  * otherwise, return 0.
1511  */
1512 static int do_for_each_repo_ref(struct repository *r, const char *prefix,
1513                                 each_repo_ref_fn fn, int trim, int flags,
1514                                 void *cb_data)
1515 {
1516         struct ref_iterator *iter;
1517         struct ref_store *refs = get_main_ref_store(r);
1518
1519         if (!refs)
1520                 return 0;
1521
1522         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1523
1524         return do_for_each_repo_ref_iterator(r, iter, fn, cb_data);
1525 }
1526
1527 struct do_for_each_ref_help {
1528         each_ref_fn *fn;
1529         void *cb_data;
1530 };
1531
1532 static int do_for_each_ref_helper(struct repository *r,
1533                                   const char *refname,
1534                                   const struct object_id *oid,
1535                                   int flags,
1536                                   void *cb_data)
1537 {
1538         struct do_for_each_ref_help *hp = cb_data;
1539
1540         return hp->fn(refname, oid, flags, hp->cb_data);
1541 }
1542
1543 static int do_for_each_ref(struct ref_store *refs, const char *prefix,
1544                            each_ref_fn fn, int trim, int flags, void *cb_data)
1545 {
1546         struct ref_iterator *iter;
1547         struct do_for_each_ref_help hp = { fn, cb_data };
1548
1549         if (!refs)
1550                 return 0;
1551
1552         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1553
1554         return do_for_each_repo_ref_iterator(the_repository, iter,
1555                                         do_for_each_ref_helper, &hp);
1556 }
1557
1558 int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1559 {
1560         return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
1561 }
1562
1563 int for_each_ref(each_ref_fn fn, void *cb_data)
1564 {
1565         return refs_for_each_ref(get_main_ref_store(the_repository), fn, cb_data);
1566 }
1567
1568 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
1569                          each_ref_fn fn, void *cb_data)
1570 {
1571         return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
1572 }
1573
1574 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1575 {
1576         return refs_for_each_ref_in(get_main_ref_store(the_repository), prefix, fn, cb_data);
1577 }
1578
1579 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1580 {
1581         unsigned int flag = 0;
1582
1583         if (broken)
1584                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1585         return do_for_each_ref(get_main_ref_store(the_repository),
1586                                prefix, fn, 0, flag, cb_data);
1587 }
1588
1589 int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
1590                              each_ref_fn fn, void *cb_data,
1591                              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(refs, prefix, fn, 0, flag, cb_data);
1598 }
1599
1600 int for_each_replace_ref(struct repository *r, each_repo_ref_fn fn, void *cb_data)
1601 {
1602         return do_for_each_repo_ref(r, git_replace_ref_base, fn,
1603                                     strlen(git_replace_ref_base),
1604                                     DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1605 }
1606
1607 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1608 {
1609         struct strbuf buf = STRBUF_INIT;
1610         int ret;
1611         strbuf_addf(&buf, "%srefs/", get_git_namespace());
1612         ret = do_for_each_ref(get_main_ref_store(the_repository),
1613                               buf.buf, fn, 0, 0, cb_data);
1614         strbuf_release(&buf);
1615         return ret;
1616 }
1617
1618 int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1619 {
1620         return do_for_each_ref(refs, "", fn, 0,
1621                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1622 }
1623
1624 int for_each_rawref(each_ref_fn fn, void *cb_data)
1625 {
1626         return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
1627 }
1628
1629 int refs_read_raw_ref(struct ref_store *ref_store,
1630                       const char *refname, struct object_id *oid,
1631                       struct strbuf *referent, unsigned int *type)
1632 {
1633         return ref_store->be->read_raw_ref(ref_store, refname, oid, referent, type);
1634 }
1635
1636 /* This function needs to return a meaningful errno on failure */
1637 const char *refs_resolve_ref_unsafe(struct ref_store *refs,
1638                                     const char *refname,
1639                                     int resolve_flags,
1640                                     struct object_id *oid, int *flags)
1641 {
1642         static struct strbuf sb_refname = STRBUF_INIT;
1643         struct object_id unused_oid;
1644         int unused_flags;
1645         int symref_count;
1646
1647         if (!oid)
1648                 oid = &unused_oid;
1649         if (!flags)
1650                 flags = &unused_flags;
1651
1652         *flags = 0;
1653
1654         if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1655                 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1656                     !refname_is_safe(refname)) {
1657                         errno = EINVAL;
1658                         return NULL;
1659                 }
1660
1661                 /*
1662                  * dwim_ref() uses REF_ISBROKEN to distinguish between
1663                  * missing refs and refs that were present but invalid,
1664                  * to complain about the latter to stderr.
1665                  *
1666                  * We don't know whether the ref exists, so don't set
1667                  * REF_ISBROKEN yet.
1668                  */
1669                 *flags |= REF_BAD_NAME;
1670         }
1671
1672         for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
1673                 unsigned int read_flags = 0;
1674
1675                 if (refs_read_raw_ref(refs, refname,
1676                                       oid, &sb_refname, &read_flags)) {
1677                         *flags |= read_flags;
1678
1679                         /* In reading mode, refs must eventually resolve */
1680                         if (resolve_flags & RESOLVE_REF_READING)
1681                                 return NULL;
1682
1683                         /*
1684                          * Otherwise a missing ref is OK. But the files backend
1685                          * may show errors besides ENOENT if there are
1686                          * similarly-named refs.
1687                          */
1688                         if (errno != ENOENT &&
1689                             errno != EISDIR &&
1690                             errno != ENOTDIR)
1691                                 return NULL;
1692
1693                         oidclr(oid);
1694                         if (*flags & REF_BAD_NAME)
1695                                 *flags |= REF_ISBROKEN;
1696                         return refname;
1697                 }
1698
1699                 *flags |= read_flags;
1700
1701                 if (!(read_flags & REF_ISSYMREF)) {
1702                         if (*flags & REF_BAD_NAME) {
1703                                 oidclr(oid);
1704                                 *flags |= REF_ISBROKEN;
1705                         }
1706                         return refname;
1707                 }
1708
1709                 refname = sb_refname.buf;
1710                 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1711                         oidclr(oid);
1712                         return refname;
1713                 }
1714                 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1715                         if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1716                             !refname_is_safe(refname)) {
1717                                 errno = EINVAL;
1718                                 return NULL;
1719                         }
1720
1721                         *flags |= REF_ISBROKEN | REF_BAD_NAME;
1722                 }
1723         }
1724
1725         errno = ELOOP;
1726         return NULL;
1727 }
1728
1729 /* backend functions */
1730 int refs_init_db(struct strbuf *err)
1731 {
1732         struct ref_store *refs = get_main_ref_store(the_repository);
1733
1734         return refs->be->init_db(refs, err);
1735 }
1736
1737 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1738                                struct object_id *oid, int *flags)
1739 {
1740         return refs_resolve_ref_unsafe(get_main_ref_store(the_repository), refname,
1741                                        resolve_flags, oid, flags);
1742 }
1743
1744 int resolve_gitlink_ref(const char *submodule, const char *refname,
1745                         struct object_id *oid)
1746 {
1747         struct ref_store *refs;
1748         int flags;
1749
1750         refs = get_submodule_ref_store(submodule);
1751
1752         if (!refs)
1753                 return -1;
1754
1755         if (!refs_resolve_ref_unsafe(refs, refname, 0, oid, &flags) ||
1756             is_null_oid(oid))
1757                 return -1;
1758         return 0;
1759 }
1760
1761 struct ref_store_hash_entry
1762 {
1763         struct hashmap_entry ent;
1764
1765         struct ref_store *refs;
1766
1767         /* NUL-terminated identifier of the ref store: */
1768         char name[FLEX_ARRAY];
1769 };
1770
1771 static int ref_store_hash_cmp(const void *unused_cmp_data,
1772                               const struct hashmap_entry *eptr,
1773                               const struct hashmap_entry *entry_or_key,
1774                               const void *keydata)
1775 {
1776         const struct ref_store_hash_entry *e1, *e2;
1777         const char *name;
1778
1779         e1 = container_of(eptr, const struct ref_store_hash_entry, ent);
1780         e2 = container_of(entry_or_key, const struct ref_store_hash_entry, ent);
1781         name = keydata ? keydata : e2->name;
1782
1783         return strcmp(e1->name, name);
1784 }
1785
1786 static struct ref_store_hash_entry *alloc_ref_store_hash_entry(
1787                 const char *name, struct ref_store *refs)
1788 {
1789         struct ref_store_hash_entry *entry;
1790
1791         FLEX_ALLOC_STR(entry, name, name);
1792         hashmap_entry_init(&entry->ent, strhash(name));
1793         entry->refs = refs;
1794         return entry;
1795 }
1796
1797 /* A hashmap of ref_stores, stored by submodule name: */
1798 static struct hashmap submodule_ref_stores;
1799
1800 /* A hashmap of ref_stores, stored by worktree id: */
1801 static struct hashmap worktree_ref_stores;
1802
1803 /*
1804  * Look up a ref store by name. If that ref_store hasn't been
1805  * registered yet, return NULL.
1806  */
1807 static struct ref_store *lookup_ref_store_map(struct hashmap *map,
1808                                               const char *name)
1809 {
1810         struct ref_store_hash_entry *entry;
1811         unsigned int hash;
1812
1813         if (!map->tablesize)
1814                 /* It's initialized on demand in register_ref_store(). */
1815                 return NULL;
1816
1817         hash = strhash(name);
1818         entry = hashmap_get_entry_from_hash(map, hash, name,
1819                                         struct ref_store_hash_entry, ent);
1820         return entry ? entry->refs : NULL;
1821 }
1822
1823 /*
1824  * Create, record, and return a ref_store instance for the specified
1825  * gitdir.
1826  */
1827 static struct ref_store *ref_store_init(const char *gitdir,
1828                                         unsigned int flags)
1829 {
1830         const char *be_name = "files";
1831         struct ref_storage_be *be = find_ref_storage_backend(be_name);
1832         struct ref_store *refs;
1833
1834         if (!be)
1835                 BUG("reference backend %s is unknown", be_name);
1836
1837         refs = be->init(gitdir, flags);
1838         return refs;
1839 }
1840
1841 struct ref_store *get_main_ref_store(struct repository *r)
1842 {
1843         if (r->refs_private)
1844                 return r->refs_private;
1845
1846         if (!r->gitdir)
1847                 BUG("attempting to get main_ref_store outside of repository");
1848
1849         r->refs_private = ref_store_init(r->gitdir, REF_STORE_ALL_CAPS);
1850         return r->refs_private;
1851 }
1852
1853 /*
1854  * Associate a ref store with a name. It is a fatal error to call this
1855  * function twice for the same name.
1856  */
1857 static void register_ref_store_map(struct hashmap *map,
1858                                    const char *type,
1859                                    struct ref_store *refs,
1860                                    const char *name)
1861 {
1862         struct ref_store_hash_entry *entry;
1863
1864         if (!map->tablesize)
1865                 hashmap_init(map, ref_store_hash_cmp, NULL, 0);
1866
1867         entry = alloc_ref_store_hash_entry(name, refs);
1868         if (hashmap_put(map, &entry->ent))
1869                 BUG("%s ref_store '%s' initialized twice", type, name);
1870 }
1871
1872 struct ref_store *get_submodule_ref_store(const char *submodule)
1873 {
1874         struct strbuf submodule_sb = STRBUF_INIT;
1875         struct ref_store *refs;
1876         char *to_free = NULL;
1877         size_t len;
1878
1879         if (!submodule)
1880                 return NULL;
1881
1882         len = strlen(submodule);
1883         while (len && is_dir_sep(submodule[len - 1]))
1884                 len--;
1885         if (!len)
1886                 return NULL;
1887
1888         if (submodule[len])
1889                 /* We need to strip off one or more trailing slashes */
1890                 submodule = to_free = xmemdupz(submodule, len);
1891
1892         refs = lookup_ref_store_map(&submodule_ref_stores, submodule);
1893         if (refs)
1894                 goto done;
1895
1896         strbuf_addstr(&submodule_sb, submodule);
1897         if (!is_nonbare_repository_dir(&submodule_sb))
1898                 goto done;
1899
1900         if (submodule_to_gitdir(&submodule_sb, submodule))
1901                 goto done;
1902
1903         /* assume that add_submodule_odb() has been called */
1904         refs = ref_store_init(submodule_sb.buf,
1905                               REF_STORE_READ | REF_STORE_ODB);
1906         register_ref_store_map(&submodule_ref_stores, "submodule",
1907                                refs, submodule);
1908
1909 done:
1910         strbuf_release(&submodule_sb);
1911         free(to_free);
1912
1913         return refs;
1914 }
1915
1916 struct ref_store *get_worktree_ref_store(const struct worktree *wt)
1917 {
1918         struct ref_store *refs;
1919         const char *id;
1920
1921         if (wt->is_current)
1922                 return get_main_ref_store(the_repository);
1923
1924         id = wt->id ? wt->id : "/";
1925         refs = lookup_ref_store_map(&worktree_ref_stores, id);
1926         if (refs)
1927                 return refs;
1928
1929         if (wt->id)
1930                 refs = ref_store_init(git_common_path("worktrees/%s", wt->id),
1931                                       REF_STORE_ALL_CAPS);
1932         else
1933                 refs = ref_store_init(get_git_common_dir(),
1934                                       REF_STORE_ALL_CAPS);
1935
1936         if (refs)
1937                 register_ref_store_map(&worktree_ref_stores, "worktree",
1938                                        refs, id);
1939         return refs;
1940 }
1941
1942 void base_ref_store_init(struct ref_store *refs,
1943                          const struct ref_storage_be *be)
1944 {
1945         refs->be = be;
1946 }
1947
1948 /* backend functions */
1949 int refs_pack_refs(struct ref_store *refs, unsigned int flags)
1950 {
1951         return refs->be->pack_refs(refs, flags);
1952 }
1953
1954 int refs_peel_ref(struct ref_store *refs, const char *refname,
1955                   struct object_id *oid)
1956 {
1957         int flag;
1958         struct object_id base;
1959
1960         if (current_ref_iter && current_ref_iter->refname == refname) {
1961                 struct object_id peeled;
1962
1963                 if (ref_iterator_peel(current_ref_iter, &peeled))
1964                         return -1;
1965                 oidcpy(oid, &peeled);
1966                 return 0;
1967         }
1968
1969         if (refs_read_ref_full(refs, refname,
1970                                RESOLVE_REF_READING, &base, &flag))
1971                 return -1;
1972
1973         return peel_object(&base, oid);
1974 }
1975
1976 int peel_ref(const char *refname, struct object_id *oid)
1977 {
1978         return refs_peel_ref(get_main_ref_store(the_repository), refname, oid);
1979 }
1980
1981 int refs_create_symref(struct ref_store *refs,
1982                        const char *ref_target,
1983                        const char *refs_heads_master,
1984                        const char *logmsg)
1985 {
1986         return refs->be->create_symref(refs, ref_target,
1987                                        refs_heads_master,
1988                                        logmsg);
1989 }
1990
1991 int create_symref(const char *ref_target, const char *refs_heads_master,
1992                   const char *logmsg)
1993 {
1994         return refs_create_symref(get_main_ref_store(the_repository), ref_target,
1995                                   refs_heads_master, logmsg);
1996 }
1997
1998 int ref_update_reject_duplicates(struct string_list *refnames,
1999                                  struct strbuf *err)
2000 {
2001         size_t i, n = refnames->nr;
2002
2003         assert(err);
2004
2005         for (i = 1; i < n; i++) {
2006                 int cmp = strcmp(refnames->items[i - 1].string,
2007                                  refnames->items[i].string);
2008
2009                 if (!cmp) {
2010                         strbuf_addf(err,
2011                                     _("multiple updates for ref '%s' not allowed"),
2012                                     refnames->items[i].string);
2013                         return 1;
2014                 } else if (cmp > 0) {
2015                         BUG("ref_update_reject_duplicates() received unsorted list");
2016                 }
2017         }
2018         return 0;
2019 }
2020
2021 static const char hook_not_found;
2022 static const char *hook;
2023
2024 static int run_transaction_hook(struct ref_transaction *transaction,
2025                                 const char *state)
2026 {
2027         struct child_process proc = CHILD_PROCESS_INIT;
2028         struct strbuf buf = STRBUF_INIT;
2029         int ret = 0, i;
2030
2031         if (hook == &hook_not_found)
2032                 return ret;
2033         if (!hook)
2034                 hook = find_hook("reference-transaction");
2035         if (!hook) {
2036                 hook = &hook_not_found;
2037                 return ret;
2038         }
2039
2040         argv_array_pushl(&proc.args, hook, state, NULL);
2041         proc.in = -1;
2042         proc.stdout_to_stderr = 1;
2043         proc.trace2_hook_name = "reference-transaction";
2044
2045         ret = start_command(&proc);
2046         if (ret)
2047                 return ret;
2048
2049         sigchain_push(SIGPIPE, SIG_IGN);
2050
2051         for (i = 0; i < transaction->nr; i++) {
2052                 struct ref_update *update = transaction->updates[i];
2053
2054                 strbuf_reset(&buf);
2055                 strbuf_addf(&buf, "%s %s %s\n",
2056                             oid_to_hex(&update->old_oid),
2057                             oid_to_hex(&update->new_oid),
2058                             update->refname);
2059
2060                 if (write_in_full(proc.in, buf.buf, buf.len) < 0) {
2061                         if (errno != EPIPE)
2062                                 ret = -1;
2063                         break;
2064                 }
2065         }
2066
2067         close(proc.in);
2068         sigchain_pop(SIGPIPE);
2069         strbuf_release(&buf);
2070
2071         ret |= finish_command(&proc);
2072         return ret;
2073 }
2074
2075 int ref_transaction_prepare(struct ref_transaction *transaction,
2076                             struct strbuf *err)
2077 {
2078         struct ref_store *refs = transaction->ref_store;
2079         int ret;
2080
2081         switch (transaction->state) {
2082         case REF_TRANSACTION_OPEN:
2083                 /* Good. */
2084                 break;
2085         case REF_TRANSACTION_PREPARED:
2086                 BUG("prepare called twice on reference transaction");
2087                 break;
2088         case REF_TRANSACTION_CLOSED:
2089                 BUG("prepare called on a closed reference transaction");
2090                 break;
2091         default:
2092                 BUG("unexpected reference transaction state");
2093                 break;
2094         }
2095
2096         if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
2097                 strbuf_addstr(err,
2098                               _("ref updates forbidden inside quarantine environment"));
2099                 return -1;
2100         }
2101
2102         ret = refs->be->transaction_prepare(refs, transaction, err);
2103         if (ret)
2104                 return ret;
2105
2106         ret = run_transaction_hook(transaction, "prepared");
2107         if (ret) {
2108                 ref_transaction_abort(transaction, err);
2109                 die(_("ref updates aborted by hook"));
2110         }
2111
2112         return 0;
2113 }
2114
2115 int ref_transaction_abort(struct ref_transaction *transaction,
2116                           struct strbuf *err)
2117 {
2118         struct ref_store *refs = transaction->ref_store;
2119         int ret = 0;
2120
2121         switch (transaction->state) {
2122         case REF_TRANSACTION_OPEN:
2123                 /* No need to abort explicitly. */
2124                 break;
2125         case REF_TRANSACTION_PREPARED:
2126                 ret = refs->be->transaction_abort(refs, transaction, err);
2127                 break;
2128         case REF_TRANSACTION_CLOSED:
2129                 BUG("abort called on a closed reference transaction");
2130                 break;
2131         default:
2132                 BUG("unexpected reference transaction state");
2133                 break;
2134         }
2135
2136         run_transaction_hook(transaction, "aborted");
2137
2138         ref_transaction_free(transaction);
2139         return ret;
2140 }
2141
2142 int ref_transaction_commit(struct ref_transaction *transaction,
2143                            struct strbuf *err)
2144 {
2145         struct ref_store *refs = transaction->ref_store;
2146         int ret;
2147
2148         switch (transaction->state) {
2149         case REF_TRANSACTION_OPEN:
2150                 /* Need to prepare first. */
2151                 ret = ref_transaction_prepare(transaction, err);
2152                 if (ret)
2153                         return ret;
2154                 break;
2155         case REF_TRANSACTION_PREPARED:
2156                 /* Fall through to finish. */
2157                 break;
2158         case REF_TRANSACTION_CLOSED:
2159                 BUG("commit called on a closed reference transaction");
2160                 break;
2161         default:
2162                 BUG("unexpected reference transaction state");
2163                 break;
2164         }
2165
2166         ret = refs->be->transaction_finish(refs, transaction, err);
2167         if (!ret)
2168                 run_transaction_hook(transaction, "committed");
2169         return ret;
2170 }
2171
2172 int refs_verify_refname_available(struct ref_store *refs,
2173                                   const char *refname,
2174                                   const struct string_list *extras,
2175                                   const struct string_list *skip,
2176                                   struct strbuf *err)
2177 {
2178         const char *slash;
2179         const char *extra_refname;
2180         struct strbuf dirname = STRBUF_INIT;
2181         struct strbuf referent = STRBUF_INIT;
2182         struct object_id oid;
2183         unsigned int type;
2184         struct ref_iterator *iter;
2185         int ok;
2186         int ret = -1;
2187
2188         /*
2189          * For the sake of comments in this function, suppose that
2190          * refname is "refs/foo/bar".
2191          */
2192
2193         assert(err);
2194
2195         strbuf_grow(&dirname, strlen(refname) + 1);
2196         for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
2197                 /* Expand dirname to the new prefix, not including the trailing slash: */
2198                 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
2199
2200                 /*
2201                  * We are still at a leading dir of the refname (e.g.,
2202                  * "refs/foo"; if there is a reference with that name,
2203                  * it is a conflict, *unless* it is in skip.
2204                  */
2205                 if (skip && string_list_has_string(skip, dirname.buf))
2206                         continue;
2207
2208                 if (!refs_read_raw_ref(refs, dirname.buf, &oid, &referent, &type)) {
2209                         strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
2210                                     dirname.buf, refname);
2211                         goto cleanup;
2212                 }
2213
2214                 if (extras && string_list_has_string(extras, dirname.buf)) {
2215                         strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
2216                                     refname, dirname.buf);
2217                         goto cleanup;
2218                 }
2219         }
2220
2221         /*
2222          * We are at the leaf of our refname (e.g., "refs/foo/bar").
2223          * There is no point in searching for a reference with that
2224          * name, because a refname isn't considered to conflict with
2225          * itself. But we still need to check for references whose
2226          * names are in the "refs/foo/bar/" namespace, because they
2227          * *do* conflict.
2228          */
2229         strbuf_addstr(&dirname, refname + dirname.len);
2230         strbuf_addch(&dirname, '/');
2231
2232         iter = refs_ref_iterator_begin(refs, dirname.buf, 0,
2233                                        DO_FOR_EACH_INCLUDE_BROKEN);
2234         while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
2235                 if (skip &&
2236                     string_list_has_string(skip, iter->refname))
2237                         continue;
2238
2239                 strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
2240                             iter->refname, refname);
2241                 ref_iterator_abort(iter);
2242                 goto cleanup;
2243         }
2244
2245         if (ok != ITER_DONE)
2246                 BUG("error while iterating over references");
2247
2248         extra_refname = find_descendant_ref(dirname.buf, extras, skip);
2249         if (extra_refname)
2250                 strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
2251                             refname, extra_refname);
2252         else
2253                 ret = 0;
2254
2255 cleanup:
2256         strbuf_release(&referent);
2257         strbuf_release(&dirname);
2258         return ret;
2259 }
2260
2261 int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2262 {
2263         struct ref_iterator *iter;
2264         struct do_for_each_ref_help hp = { fn, cb_data };
2265
2266         iter = refs->be->reflog_iterator_begin(refs);
2267
2268         return do_for_each_repo_ref_iterator(the_repository, iter,
2269                                              do_for_each_ref_helper, &hp);
2270 }
2271
2272 int for_each_reflog(each_ref_fn fn, void *cb_data)
2273 {
2274         return refs_for_each_reflog(get_main_ref_store(the_repository), fn, cb_data);
2275 }
2276
2277 int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
2278                                      const char *refname,
2279                                      each_reflog_ent_fn fn,
2280                                      void *cb_data)
2281 {
2282         return refs->be->for_each_reflog_ent_reverse(refs, refname,
2283                                                      fn, cb_data);
2284 }
2285
2286 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
2287                                 void *cb_data)
2288 {
2289         return refs_for_each_reflog_ent_reverse(get_main_ref_store(the_repository),
2290                                                 refname, fn, cb_data);
2291 }
2292
2293 int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
2294                              each_reflog_ent_fn fn, void *cb_data)
2295 {
2296         return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
2297 }
2298
2299 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
2300                         void *cb_data)
2301 {
2302         return refs_for_each_reflog_ent(get_main_ref_store(the_repository), refname,
2303                                         fn, cb_data);
2304 }
2305
2306 int refs_reflog_exists(struct ref_store *refs, const char *refname)
2307 {
2308         return refs->be->reflog_exists(refs, refname);
2309 }
2310
2311 int reflog_exists(const char *refname)
2312 {
2313         return refs_reflog_exists(get_main_ref_store(the_repository), refname);
2314 }
2315
2316 int refs_create_reflog(struct ref_store *refs, const char *refname,
2317                        int force_create, struct strbuf *err)
2318 {
2319         return refs->be->create_reflog(refs, refname, force_create, err);
2320 }
2321
2322 int safe_create_reflog(const char *refname, int force_create,
2323                        struct strbuf *err)
2324 {
2325         return refs_create_reflog(get_main_ref_store(the_repository), refname,
2326                                   force_create, err);
2327 }
2328
2329 int refs_delete_reflog(struct ref_store *refs, const char *refname)
2330 {
2331         return refs->be->delete_reflog(refs, refname);
2332 }
2333
2334 int delete_reflog(const char *refname)
2335 {
2336         return refs_delete_reflog(get_main_ref_store(the_repository), refname);
2337 }
2338
2339 int refs_reflog_expire(struct ref_store *refs,
2340                        const char *refname, const struct object_id *oid,
2341                        unsigned int flags,
2342                        reflog_expiry_prepare_fn prepare_fn,
2343                        reflog_expiry_should_prune_fn should_prune_fn,
2344                        reflog_expiry_cleanup_fn cleanup_fn,
2345                        void *policy_cb_data)
2346 {
2347         return refs->be->reflog_expire(refs, refname, oid, flags,
2348                                        prepare_fn, should_prune_fn,
2349                                        cleanup_fn, policy_cb_data);
2350 }
2351
2352 int reflog_expire(const char *refname, const struct object_id *oid,
2353                   unsigned int flags,
2354                   reflog_expiry_prepare_fn prepare_fn,
2355                   reflog_expiry_should_prune_fn should_prune_fn,
2356                   reflog_expiry_cleanup_fn cleanup_fn,
2357                   void *policy_cb_data)
2358 {
2359         return refs_reflog_expire(get_main_ref_store(the_repository),
2360                                   refname, oid, flags,
2361                                   prepare_fn, should_prune_fn,
2362                                   cleanup_fn, policy_cb_data);
2363 }
2364
2365 int initial_ref_transaction_commit(struct ref_transaction *transaction,
2366                                    struct strbuf *err)
2367 {
2368         struct ref_store *refs = transaction->ref_store;
2369
2370         return refs->be->initial_transaction_commit(refs, transaction, err);
2371 }
2372
2373 int refs_delete_refs(struct ref_store *refs, const char *msg,
2374                      struct string_list *refnames, unsigned int flags)
2375 {
2376         return refs->be->delete_refs(refs, msg, refnames, flags);
2377 }
2378
2379 int delete_refs(const char *msg, struct string_list *refnames,
2380                 unsigned int flags)
2381 {
2382         return refs_delete_refs(get_main_ref_store(the_repository), msg, refnames, flags);
2383 }
2384
2385 int refs_rename_ref(struct ref_store *refs, const char *oldref,
2386                     const char *newref, const char *logmsg)
2387 {
2388         return refs->be->rename_ref(refs, oldref, newref, logmsg);
2389 }
2390
2391 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
2392 {
2393         return refs_rename_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
2394 }
2395
2396 int refs_copy_existing_ref(struct ref_store *refs, const char *oldref,
2397                     const char *newref, const char *logmsg)
2398 {
2399         return refs->be->copy_ref(refs, oldref, newref, logmsg);
2400 }
2401
2402 int copy_existing_ref(const char *oldref, const char *newref, const char *logmsg)
2403 {
2404         return refs_copy_existing_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
2405 }