Merge branch 'jk/reject-newer-extensions-in-v0' into master
[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 static 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 static char *normalize_reflog_message(const char *msg)
923 {
924         struct strbuf sb = STRBUF_INIT;
925
926         if (msg && *msg)
927                 copy_reflog_msg(&sb, msg);
928         return strbuf_detach(&sb, NULL);
929 }
930
931 int should_autocreate_reflog(const char *refname)
932 {
933         switch (log_all_ref_updates) {
934         case LOG_REFS_ALWAYS:
935                 return 1;
936         case LOG_REFS_NORMAL:
937                 return starts_with(refname, "refs/heads/") ||
938                         starts_with(refname, "refs/remotes/") ||
939                         starts_with(refname, "refs/notes/") ||
940                         !strcmp(refname, "HEAD");
941         default:
942                 return 0;
943         }
944 }
945
946 int is_branch(const char *refname)
947 {
948         return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
949 }
950
951 struct read_ref_at_cb {
952         const char *refname;
953         timestamp_t at_time;
954         int cnt;
955         int reccnt;
956         struct object_id *oid;
957         int found_it;
958
959         struct object_id ooid;
960         struct object_id noid;
961         int tz;
962         timestamp_t date;
963         char **msg;
964         timestamp_t *cutoff_time;
965         int *cutoff_tz;
966         int *cutoff_cnt;
967 };
968
969 static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
970                 const char *email, timestamp_t timestamp, int tz,
971                 const char *message, void *cb_data)
972 {
973         struct read_ref_at_cb *cb = cb_data;
974
975         cb->reccnt++;
976         cb->tz = tz;
977         cb->date = timestamp;
978
979         if (timestamp <= cb->at_time || cb->cnt == 0) {
980                 if (cb->msg)
981                         *cb->msg = xstrdup(message);
982                 if (cb->cutoff_time)
983                         *cb->cutoff_time = timestamp;
984                 if (cb->cutoff_tz)
985                         *cb->cutoff_tz = tz;
986                 if (cb->cutoff_cnt)
987                         *cb->cutoff_cnt = cb->reccnt - 1;
988                 /*
989                  * we have not yet updated cb->[n|o]oid so they still
990                  * hold the values for the previous record.
991                  */
992                 if (!is_null_oid(&cb->ooid)) {
993                         oidcpy(cb->oid, noid);
994                         if (!oideq(&cb->ooid, noid))
995                                 warning(_("log for ref %s has gap after %s"),
996                                         cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
997                 }
998                 else if (cb->date == cb->at_time)
999                         oidcpy(cb->oid, noid);
1000                 else if (!oideq(noid, cb->oid))
1001                         warning(_("log for ref %s unexpectedly ended on %s"),
1002                                 cb->refname, show_date(cb->date, cb->tz,
1003                                                        DATE_MODE(RFC2822)));
1004                 oidcpy(&cb->ooid, ooid);
1005                 oidcpy(&cb->noid, noid);
1006                 cb->found_it = 1;
1007                 return 1;
1008         }
1009         oidcpy(&cb->ooid, ooid);
1010         oidcpy(&cb->noid, noid);
1011         if (cb->cnt > 0)
1012                 cb->cnt--;
1013         return 0;
1014 }
1015
1016 static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
1017                                   const char *email, timestamp_t timestamp,
1018                                   int tz, const char *message, void *cb_data)
1019 {
1020         struct read_ref_at_cb *cb = cb_data;
1021
1022         if (cb->msg)
1023                 *cb->msg = xstrdup(message);
1024         if (cb->cutoff_time)
1025                 *cb->cutoff_time = timestamp;
1026         if (cb->cutoff_tz)
1027                 *cb->cutoff_tz = tz;
1028         if (cb->cutoff_cnt)
1029                 *cb->cutoff_cnt = cb->reccnt;
1030         oidcpy(cb->oid, ooid);
1031         if (is_null_oid(cb->oid))
1032                 oidcpy(cb->oid, noid);
1033         /* We just want the first entry */
1034         return 1;
1035 }
1036
1037 int read_ref_at(struct ref_store *refs, const char *refname,
1038                 unsigned int flags, timestamp_t at_time, int cnt,
1039                 struct object_id *oid, char **msg,
1040                 timestamp_t *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
1041 {
1042         struct read_ref_at_cb cb;
1043
1044         memset(&cb, 0, sizeof(cb));
1045         cb.refname = refname;
1046         cb.at_time = at_time;
1047         cb.cnt = cnt;
1048         cb.msg = msg;
1049         cb.cutoff_time = cutoff_time;
1050         cb.cutoff_tz = cutoff_tz;
1051         cb.cutoff_cnt = cutoff_cnt;
1052         cb.oid = oid;
1053
1054         refs_for_each_reflog_ent_reverse(refs, refname, read_ref_at_ent, &cb);
1055
1056         if (!cb.reccnt) {
1057                 if (flags & GET_OID_QUIETLY)
1058                         exit(128);
1059                 else
1060                         die(_("log for %s is empty"), refname);
1061         }
1062         if (cb.found_it)
1063                 return 0;
1064
1065         refs_for_each_reflog_ent(refs, refname, read_ref_at_ent_oldest, &cb);
1066
1067         return 1;
1068 }
1069
1070 struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
1071                                                     struct strbuf *err)
1072 {
1073         struct ref_transaction *tr;
1074         assert(err);
1075
1076         tr = xcalloc(1, sizeof(struct ref_transaction));
1077         tr->ref_store = refs;
1078         return tr;
1079 }
1080
1081 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
1082 {
1083         return ref_store_transaction_begin(get_main_ref_store(the_repository), err);
1084 }
1085
1086 void ref_transaction_free(struct ref_transaction *transaction)
1087 {
1088         size_t i;
1089
1090         if (!transaction)
1091                 return;
1092
1093         switch (transaction->state) {
1094         case REF_TRANSACTION_OPEN:
1095         case REF_TRANSACTION_CLOSED:
1096                 /* OK */
1097                 break;
1098         case REF_TRANSACTION_PREPARED:
1099                 BUG("free called on a prepared reference transaction");
1100                 break;
1101         default:
1102                 BUG("unexpected reference transaction state");
1103                 break;
1104         }
1105
1106         for (i = 0; i < transaction->nr; i++) {
1107                 free(transaction->updates[i]->msg);
1108                 free(transaction->updates[i]);
1109         }
1110         free(transaction->updates);
1111         free(transaction);
1112 }
1113
1114 struct ref_update *ref_transaction_add_update(
1115                 struct ref_transaction *transaction,
1116                 const char *refname, unsigned int flags,
1117                 const struct object_id *new_oid,
1118                 const struct object_id *old_oid,
1119                 const char *msg)
1120 {
1121         struct ref_update *update;
1122
1123         if (transaction->state != REF_TRANSACTION_OPEN)
1124                 BUG("update called for transaction that is not open");
1125
1126         FLEX_ALLOC_STR(update, refname, refname);
1127         ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
1128         transaction->updates[transaction->nr++] = update;
1129
1130         update->flags = flags;
1131
1132         if (flags & REF_HAVE_NEW)
1133                 oidcpy(&update->new_oid, new_oid);
1134         if (flags & REF_HAVE_OLD)
1135                 oidcpy(&update->old_oid, old_oid);
1136         update->msg = normalize_reflog_message(msg);
1137         return update;
1138 }
1139
1140 int ref_transaction_update(struct ref_transaction *transaction,
1141                            const char *refname,
1142                            const struct object_id *new_oid,
1143                            const struct object_id *old_oid,
1144                            unsigned int flags, const char *msg,
1145                            struct strbuf *err)
1146 {
1147         assert(err);
1148
1149         if ((new_oid && !is_null_oid(new_oid)) ?
1150             check_refname_format(refname, REFNAME_ALLOW_ONELEVEL) :
1151             !refname_is_safe(refname)) {
1152                 strbuf_addf(err, _("refusing to update ref with bad name '%s'"),
1153                             refname);
1154                 return -1;
1155         }
1156
1157         if (flags & ~REF_TRANSACTION_UPDATE_ALLOWED_FLAGS)
1158                 BUG("illegal flags 0x%x passed to ref_transaction_update()", flags);
1159
1160         flags |= (new_oid ? REF_HAVE_NEW : 0) | (old_oid ? REF_HAVE_OLD : 0);
1161
1162         ref_transaction_add_update(transaction, refname, flags,
1163                                    new_oid, old_oid, msg);
1164         return 0;
1165 }
1166
1167 int ref_transaction_create(struct ref_transaction *transaction,
1168                            const char *refname,
1169                            const struct object_id *new_oid,
1170                            unsigned int flags, const char *msg,
1171                            struct strbuf *err)
1172 {
1173         if (!new_oid || is_null_oid(new_oid))
1174                 BUG("create called without valid new_oid");
1175         return ref_transaction_update(transaction, refname, new_oid,
1176                                       &null_oid, flags, msg, err);
1177 }
1178
1179 int ref_transaction_delete(struct ref_transaction *transaction,
1180                            const char *refname,
1181                            const struct object_id *old_oid,
1182                            unsigned int flags, const char *msg,
1183                            struct strbuf *err)
1184 {
1185         if (old_oid && is_null_oid(old_oid))
1186                 BUG("delete called with old_oid set to zeros");
1187         return ref_transaction_update(transaction, refname,
1188                                       &null_oid, old_oid,
1189                                       flags, msg, err);
1190 }
1191
1192 int ref_transaction_verify(struct ref_transaction *transaction,
1193                            const char *refname,
1194                            const struct object_id *old_oid,
1195                            unsigned int flags,
1196                            struct strbuf *err)
1197 {
1198         if (!old_oid)
1199                 BUG("verify called with old_oid set to NULL");
1200         return ref_transaction_update(transaction, refname,
1201                                       NULL, old_oid,
1202                                       flags, NULL, err);
1203 }
1204
1205 int refs_update_ref(struct ref_store *refs, const char *msg,
1206                     const char *refname, const struct object_id *new_oid,
1207                     const struct object_id *old_oid, unsigned int flags,
1208                     enum action_on_err onerr)
1209 {
1210         struct ref_transaction *t = NULL;
1211         struct strbuf err = STRBUF_INIT;
1212         int ret = 0;
1213
1214         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
1215                 assert(refs == get_main_ref_store(the_repository));
1216                 ret = write_pseudoref(refname, new_oid, old_oid, &err);
1217         } else {
1218                 t = ref_store_transaction_begin(refs, &err);
1219                 if (!t ||
1220                     ref_transaction_update(t, refname, new_oid, old_oid,
1221                                            flags, msg, &err) ||
1222                     ref_transaction_commit(t, &err)) {
1223                         ret = 1;
1224                         ref_transaction_free(t);
1225                 }
1226         }
1227         if (ret) {
1228                 const char *str = _("update_ref failed for ref '%s': %s");
1229
1230                 switch (onerr) {
1231                 case UPDATE_REFS_MSG_ON_ERR:
1232                         error(str, refname, err.buf);
1233                         break;
1234                 case UPDATE_REFS_DIE_ON_ERR:
1235                         die(str, refname, err.buf);
1236                         break;
1237                 case UPDATE_REFS_QUIET_ON_ERR:
1238                         break;
1239                 }
1240                 strbuf_release(&err);
1241                 return 1;
1242         }
1243         strbuf_release(&err);
1244         if (t)
1245                 ref_transaction_free(t);
1246         return 0;
1247 }
1248
1249 int update_ref(const char *msg, const char *refname,
1250                const struct object_id *new_oid,
1251                const struct object_id *old_oid,
1252                unsigned int flags, enum action_on_err onerr)
1253 {
1254         return refs_update_ref(get_main_ref_store(the_repository), msg, refname, new_oid,
1255                                old_oid, flags, onerr);
1256 }
1257
1258 char *refs_shorten_unambiguous_ref(struct ref_store *refs,
1259                                    const char *refname, int strict)
1260 {
1261         int i;
1262         static char **scanf_fmts;
1263         static int nr_rules;
1264         char *short_name;
1265         struct strbuf resolved_buf = STRBUF_INIT;
1266
1267         if (!nr_rules) {
1268                 /*
1269                  * Pre-generate scanf formats from ref_rev_parse_rules[].
1270                  * Generate a format suitable for scanf from a
1271                  * ref_rev_parse_rules rule by interpolating "%s" at the
1272                  * location of the "%.*s".
1273                  */
1274                 size_t total_len = 0;
1275                 size_t offset = 0;
1276
1277                 /* the rule list is NULL terminated, count them first */
1278                 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
1279                         /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
1280                         total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
1281
1282                 scanf_fmts = xmalloc(st_add(st_mult(sizeof(char *), nr_rules), total_len));
1283
1284                 offset = 0;
1285                 for (i = 0; i < nr_rules; i++) {
1286                         assert(offset < total_len);
1287                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
1288                         offset += xsnprintf(scanf_fmts[i], total_len - offset,
1289                                             ref_rev_parse_rules[i], 2, "%s") + 1;
1290                 }
1291         }
1292
1293         /* bail out if there are no rules */
1294         if (!nr_rules)
1295                 return xstrdup(refname);
1296
1297         /* buffer for scanf result, at most refname must fit */
1298         short_name = xstrdup(refname);
1299
1300         /* skip first rule, it will always match */
1301         for (i = nr_rules - 1; i > 0 ; --i) {
1302                 int j;
1303                 int rules_to_fail = i;
1304                 int short_name_len;
1305
1306                 if (1 != sscanf(refname, scanf_fmts[i], short_name))
1307                         continue;
1308
1309                 short_name_len = strlen(short_name);
1310
1311                 /*
1312                  * in strict mode, all (except the matched one) rules
1313                  * must fail to resolve to a valid non-ambiguous ref
1314                  */
1315                 if (strict)
1316                         rules_to_fail = nr_rules;
1317
1318                 /*
1319                  * check if the short name resolves to a valid ref,
1320                  * but use only rules prior to the matched one
1321                  */
1322                 for (j = 0; j < rules_to_fail; j++) {
1323                         const char *rule = ref_rev_parse_rules[j];
1324
1325                         /* skip matched rule */
1326                         if (i == j)
1327                                 continue;
1328
1329                         /*
1330                          * the short name is ambiguous, if it resolves
1331                          * (with this previous rule) to a valid ref
1332                          * read_ref() returns 0 on success
1333                          */
1334                         strbuf_reset(&resolved_buf);
1335                         strbuf_addf(&resolved_buf, rule,
1336                                     short_name_len, short_name);
1337                         if (refs_ref_exists(refs, resolved_buf.buf))
1338                                 break;
1339                 }
1340
1341                 /*
1342                  * short name is non-ambiguous if all previous rules
1343                  * haven't resolved to a valid ref
1344                  */
1345                 if (j == rules_to_fail) {
1346                         strbuf_release(&resolved_buf);
1347                         return short_name;
1348                 }
1349         }
1350
1351         strbuf_release(&resolved_buf);
1352         free(short_name);
1353         return xstrdup(refname);
1354 }
1355
1356 char *shorten_unambiguous_ref(const char *refname, int strict)
1357 {
1358         return refs_shorten_unambiguous_ref(get_main_ref_store(the_repository),
1359                                             refname, strict);
1360 }
1361
1362 static struct string_list *hide_refs;
1363
1364 int parse_hide_refs_config(const char *var, const char *value, const char *section)
1365 {
1366         const char *key;
1367         if (!strcmp("transfer.hiderefs", var) ||
1368             (!parse_config_key(var, section, NULL, NULL, &key) &&
1369              !strcmp(key, "hiderefs"))) {
1370                 char *ref;
1371                 int len;
1372
1373                 if (!value)
1374                         return config_error_nonbool(var);
1375                 ref = xstrdup(value);
1376                 len = strlen(ref);
1377                 while (len && ref[len - 1] == '/')
1378                         ref[--len] = '\0';
1379                 if (!hide_refs) {
1380                         hide_refs = xcalloc(1, sizeof(*hide_refs));
1381                         hide_refs->strdup_strings = 1;
1382                 }
1383                 string_list_append(hide_refs, ref);
1384         }
1385         return 0;
1386 }
1387
1388 int ref_is_hidden(const char *refname, const char *refname_full)
1389 {
1390         int i;
1391
1392         if (!hide_refs)
1393                 return 0;
1394         for (i = hide_refs->nr - 1; i >= 0; i--) {
1395                 const char *match = hide_refs->items[i].string;
1396                 const char *subject;
1397                 int neg = 0;
1398                 const char *p;
1399
1400                 if (*match == '!') {
1401                         neg = 1;
1402                         match++;
1403                 }
1404
1405                 if (*match == '^') {
1406                         subject = refname_full;
1407                         match++;
1408                 } else {
1409                         subject = refname;
1410                 }
1411
1412                 /* refname can be NULL when namespaces are used. */
1413                 if (subject &&
1414                     skip_prefix(subject, match, &p) &&
1415                     (!*p || *p == '/'))
1416                         return !neg;
1417         }
1418         return 0;
1419 }
1420
1421 const char *find_descendant_ref(const char *dirname,
1422                                 const struct string_list *extras,
1423                                 const struct string_list *skip)
1424 {
1425         int pos;
1426
1427         if (!extras)
1428                 return NULL;
1429
1430         /*
1431          * Look at the place where dirname would be inserted into
1432          * extras. If there is an entry at that position that starts
1433          * with dirname (remember, dirname includes the trailing
1434          * slash) and is not in skip, then we have a conflict.
1435          */
1436         for (pos = string_list_find_insert_index(extras, dirname, 0);
1437              pos < extras->nr; pos++) {
1438                 const char *extra_refname = extras->items[pos].string;
1439
1440                 if (!starts_with(extra_refname, dirname))
1441                         break;
1442
1443                 if (!skip || !string_list_has_string(skip, extra_refname))
1444                         return extra_refname;
1445         }
1446         return NULL;
1447 }
1448
1449 int refs_rename_ref_available(struct ref_store *refs,
1450                               const char *old_refname,
1451                               const char *new_refname)
1452 {
1453         struct string_list skip = STRING_LIST_INIT_NODUP;
1454         struct strbuf err = STRBUF_INIT;
1455         int ok;
1456
1457         string_list_insert(&skip, old_refname);
1458         ok = !refs_verify_refname_available(refs, new_refname,
1459                                             NULL, &skip, &err);
1460         if (!ok)
1461                 error("%s", err.buf);
1462
1463         string_list_clear(&skip, 0);
1464         strbuf_release(&err);
1465         return ok;
1466 }
1467
1468 int refs_head_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1469 {
1470         struct object_id oid;
1471         int flag;
1472
1473         if (!refs_read_ref_full(refs, "HEAD", RESOLVE_REF_READING,
1474                                 &oid, &flag))
1475                 return fn("HEAD", &oid, flag, cb_data);
1476
1477         return 0;
1478 }
1479
1480 int head_ref(each_ref_fn fn, void *cb_data)
1481 {
1482         return refs_head_ref(get_main_ref_store(the_repository), fn, cb_data);
1483 }
1484
1485 struct ref_iterator *refs_ref_iterator_begin(
1486                 struct ref_store *refs,
1487                 const char *prefix, int trim, int flags)
1488 {
1489         struct ref_iterator *iter;
1490
1491         if (ref_paranoia < 0)
1492                 ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
1493         if (ref_paranoia)
1494                 flags |= DO_FOR_EACH_INCLUDE_BROKEN;
1495
1496         iter = refs->be->iterator_begin(refs, prefix, flags);
1497
1498         /*
1499          * `iterator_begin()` already takes care of prefix, but we
1500          * might need to do some trimming:
1501          */
1502         if (trim)
1503                 iter = prefix_ref_iterator_begin(iter, "", trim);
1504
1505         /* Sanity check for subclasses: */
1506         if (!iter->ordered)
1507                 BUG("reference iterator is not ordered");
1508
1509         return iter;
1510 }
1511
1512 /*
1513  * Call fn for each reference in the specified submodule for which the
1514  * refname begins with prefix. If trim is non-zero, then trim that
1515  * many characters off the beginning of each refname before passing
1516  * the refname to fn. flags can be DO_FOR_EACH_INCLUDE_BROKEN to
1517  * include broken references in the iteration. If fn ever returns a
1518  * non-zero value, stop the iteration and return that value;
1519  * otherwise, return 0.
1520  */
1521 static int do_for_each_repo_ref(struct repository *r, const char *prefix,
1522                                 each_repo_ref_fn fn, int trim, int flags,
1523                                 void *cb_data)
1524 {
1525         struct ref_iterator *iter;
1526         struct ref_store *refs = get_main_ref_store(r);
1527
1528         if (!refs)
1529                 return 0;
1530
1531         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1532
1533         return do_for_each_repo_ref_iterator(r, iter, fn, cb_data);
1534 }
1535
1536 struct do_for_each_ref_help {
1537         each_ref_fn *fn;
1538         void *cb_data;
1539 };
1540
1541 static int do_for_each_ref_helper(struct repository *r,
1542                                   const char *refname,
1543                                   const struct object_id *oid,
1544                                   int flags,
1545                                   void *cb_data)
1546 {
1547         struct do_for_each_ref_help *hp = cb_data;
1548
1549         return hp->fn(refname, oid, flags, hp->cb_data);
1550 }
1551
1552 static int do_for_each_ref(struct ref_store *refs, const char *prefix,
1553                            each_ref_fn fn, int trim, int flags, void *cb_data)
1554 {
1555         struct ref_iterator *iter;
1556         struct do_for_each_ref_help hp = { fn, cb_data };
1557
1558         if (!refs)
1559                 return 0;
1560
1561         iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
1562
1563         return do_for_each_repo_ref_iterator(the_repository, iter,
1564                                         do_for_each_ref_helper, &hp);
1565 }
1566
1567 int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1568 {
1569         return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
1570 }
1571
1572 int for_each_ref(each_ref_fn fn, void *cb_data)
1573 {
1574         return refs_for_each_ref(get_main_ref_store(the_repository), fn, cb_data);
1575 }
1576
1577 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
1578                          each_ref_fn fn, void *cb_data)
1579 {
1580         return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
1581 }
1582
1583 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1584 {
1585         return refs_for_each_ref_in(get_main_ref_store(the_repository), prefix, fn, cb_data);
1586 }
1587
1588 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
1589 {
1590         unsigned int flag = 0;
1591
1592         if (broken)
1593                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1594         return do_for_each_ref(get_main_ref_store(the_repository),
1595                                prefix, fn, 0, flag, cb_data);
1596 }
1597
1598 int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
1599                              each_ref_fn fn, void *cb_data,
1600                              unsigned int broken)
1601 {
1602         unsigned int flag = 0;
1603
1604         if (broken)
1605                 flag = DO_FOR_EACH_INCLUDE_BROKEN;
1606         return do_for_each_ref(refs, prefix, fn, 0, flag, cb_data);
1607 }
1608
1609 int for_each_replace_ref(struct repository *r, each_repo_ref_fn fn, void *cb_data)
1610 {
1611         return do_for_each_repo_ref(r, git_replace_ref_base, fn,
1612                                     strlen(git_replace_ref_base),
1613                                     DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1614 }
1615
1616 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1617 {
1618         struct strbuf buf = STRBUF_INIT;
1619         int ret;
1620         strbuf_addf(&buf, "%srefs/", get_git_namespace());
1621         ret = do_for_each_ref(get_main_ref_store(the_repository),
1622                               buf.buf, fn, 0, 0, cb_data);
1623         strbuf_release(&buf);
1624         return ret;
1625 }
1626
1627 int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
1628 {
1629         return do_for_each_ref(refs, "", fn, 0,
1630                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1631 }
1632
1633 int for_each_rawref(each_ref_fn fn, void *cb_data)
1634 {
1635         return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
1636 }
1637
1638 int refs_read_raw_ref(struct ref_store *ref_store,
1639                       const char *refname, struct object_id *oid,
1640                       struct strbuf *referent, unsigned int *type)
1641 {
1642         return ref_store->be->read_raw_ref(ref_store, refname, oid, referent, type);
1643 }
1644
1645 /* This function needs to return a meaningful errno on failure */
1646 const char *refs_resolve_ref_unsafe(struct ref_store *refs,
1647                                     const char *refname,
1648                                     int resolve_flags,
1649                                     struct object_id *oid, int *flags)
1650 {
1651         static struct strbuf sb_refname = STRBUF_INIT;
1652         struct object_id unused_oid;
1653         int unused_flags;
1654         int symref_count;
1655
1656         if (!oid)
1657                 oid = &unused_oid;
1658         if (!flags)
1659                 flags = &unused_flags;
1660
1661         *flags = 0;
1662
1663         if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1664                 if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1665                     !refname_is_safe(refname)) {
1666                         errno = EINVAL;
1667                         return NULL;
1668                 }
1669
1670                 /*
1671                  * dwim_ref() uses REF_ISBROKEN to distinguish between
1672                  * missing refs and refs that were present but invalid,
1673                  * to complain about the latter to stderr.
1674                  *
1675                  * We don't know whether the ref exists, so don't set
1676                  * REF_ISBROKEN yet.
1677                  */
1678                 *flags |= REF_BAD_NAME;
1679         }
1680
1681         for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
1682                 unsigned int read_flags = 0;
1683
1684                 if (refs_read_raw_ref(refs, refname,
1685                                       oid, &sb_refname, &read_flags)) {
1686                         *flags |= read_flags;
1687
1688                         /* In reading mode, refs must eventually resolve */
1689                         if (resolve_flags & RESOLVE_REF_READING)
1690                                 return NULL;
1691
1692                         /*
1693                          * Otherwise a missing ref is OK. But the files backend
1694                          * may show errors besides ENOENT if there are
1695                          * similarly-named refs.
1696                          */
1697                         if (errno != ENOENT &&
1698                             errno != EISDIR &&
1699                             errno != ENOTDIR)
1700                                 return NULL;
1701
1702                         oidclr(oid);
1703                         if (*flags & REF_BAD_NAME)
1704                                 *flags |= REF_ISBROKEN;
1705                         return refname;
1706                 }
1707
1708                 *flags |= read_flags;
1709
1710                 if (!(read_flags & REF_ISSYMREF)) {
1711                         if (*flags & REF_BAD_NAME) {
1712                                 oidclr(oid);
1713                                 *flags |= REF_ISBROKEN;
1714                         }
1715                         return refname;
1716                 }
1717
1718                 refname = sb_refname.buf;
1719                 if (resolve_flags & RESOLVE_REF_NO_RECURSE) {
1720                         oidclr(oid);
1721                         return refname;
1722                 }
1723                 if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
1724                         if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
1725                             !refname_is_safe(refname)) {
1726                                 errno = EINVAL;
1727                                 return NULL;
1728                         }
1729
1730                         *flags |= REF_ISBROKEN | REF_BAD_NAME;
1731                 }
1732         }
1733
1734         errno = ELOOP;
1735         return NULL;
1736 }
1737
1738 /* backend functions */
1739 int refs_init_db(struct strbuf *err)
1740 {
1741         struct ref_store *refs = get_main_ref_store(the_repository);
1742
1743         return refs->be->init_db(refs, err);
1744 }
1745
1746 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
1747                                struct object_id *oid, int *flags)
1748 {
1749         return refs_resolve_ref_unsafe(get_main_ref_store(the_repository), refname,
1750                                        resolve_flags, oid, flags);
1751 }
1752
1753 int resolve_gitlink_ref(const char *submodule, const char *refname,
1754                         struct object_id *oid)
1755 {
1756         struct ref_store *refs;
1757         int flags;
1758
1759         refs = get_submodule_ref_store(submodule);
1760
1761         if (!refs)
1762                 return -1;
1763
1764         if (!refs_resolve_ref_unsafe(refs, refname, 0, oid, &flags) ||
1765             is_null_oid(oid))
1766                 return -1;
1767         return 0;
1768 }
1769
1770 struct ref_store_hash_entry
1771 {
1772         struct hashmap_entry ent;
1773
1774         struct ref_store *refs;
1775
1776         /* NUL-terminated identifier of the ref store: */
1777         char name[FLEX_ARRAY];
1778 };
1779
1780 static int ref_store_hash_cmp(const void *unused_cmp_data,
1781                               const struct hashmap_entry *eptr,
1782                               const struct hashmap_entry *entry_or_key,
1783                               const void *keydata)
1784 {
1785         const struct ref_store_hash_entry *e1, *e2;
1786         const char *name;
1787
1788         e1 = container_of(eptr, const struct ref_store_hash_entry, ent);
1789         e2 = container_of(entry_or_key, const struct ref_store_hash_entry, ent);
1790         name = keydata ? keydata : e2->name;
1791
1792         return strcmp(e1->name, name);
1793 }
1794
1795 static struct ref_store_hash_entry *alloc_ref_store_hash_entry(
1796                 const char *name, struct ref_store *refs)
1797 {
1798         struct ref_store_hash_entry *entry;
1799
1800         FLEX_ALLOC_STR(entry, name, name);
1801         hashmap_entry_init(&entry->ent, strhash(name));
1802         entry->refs = refs;
1803         return entry;
1804 }
1805
1806 /* A hashmap of ref_stores, stored by submodule name: */
1807 static struct hashmap submodule_ref_stores;
1808
1809 /* A hashmap of ref_stores, stored by worktree id: */
1810 static struct hashmap worktree_ref_stores;
1811
1812 /*
1813  * Look up a ref store by name. If that ref_store hasn't been
1814  * registered yet, return NULL.
1815  */
1816 static struct ref_store *lookup_ref_store_map(struct hashmap *map,
1817                                               const char *name)
1818 {
1819         struct ref_store_hash_entry *entry;
1820         unsigned int hash;
1821
1822         if (!map->tablesize)
1823                 /* It's initialized on demand in register_ref_store(). */
1824                 return NULL;
1825
1826         hash = strhash(name);
1827         entry = hashmap_get_entry_from_hash(map, hash, name,
1828                                         struct ref_store_hash_entry, ent);
1829         return entry ? entry->refs : NULL;
1830 }
1831
1832 /*
1833  * Create, record, and return a ref_store instance for the specified
1834  * gitdir.
1835  */
1836 static struct ref_store *ref_store_init(const char *gitdir,
1837                                         unsigned int flags)
1838 {
1839         const char *be_name = "files";
1840         struct ref_storage_be *be = find_ref_storage_backend(be_name);
1841         struct ref_store *refs;
1842
1843         if (!be)
1844                 BUG("reference backend %s is unknown", be_name);
1845
1846         refs = be->init(gitdir, flags);
1847         return refs;
1848 }
1849
1850 struct ref_store *get_main_ref_store(struct repository *r)
1851 {
1852         if (r->refs_private)
1853                 return r->refs_private;
1854
1855         if (!r->gitdir)
1856                 BUG("attempting to get main_ref_store outside of repository");
1857
1858         r->refs_private = ref_store_init(r->gitdir, REF_STORE_ALL_CAPS);
1859         return r->refs_private;
1860 }
1861
1862 /*
1863  * Associate a ref store with a name. It is a fatal error to call this
1864  * function twice for the same name.
1865  */
1866 static void register_ref_store_map(struct hashmap *map,
1867                                    const char *type,
1868                                    struct ref_store *refs,
1869                                    const char *name)
1870 {
1871         struct ref_store_hash_entry *entry;
1872
1873         if (!map->tablesize)
1874                 hashmap_init(map, ref_store_hash_cmp, NULL, 0);
1875
1876         entry = alloc_ref_store_hash_entry(name, refs);
1877         if (hashmap_put(map, &entry->ent))
1878                 BUG("%s ref_store '%s' initialized twice", type, name);
1879 }
1880
1881 struct ref_store *get_submodule_ref_store(const char *submodule)
1882 {
1883         struct strbuf submodule_sb = STRBUF_INIT;
1884         struct ref_store *refs;
1885         char *to_free = NULL;
1886         size_t len;
1887
1888         if (!submodule)
1889                 return NULL;
1890
1891         len = strlen(submodule);
1892         while (len && is_dir_sep(submodule[len - 1]))
1893                 len--;
1894         if (!len)
1895                 return NULL;
1896
1897         if (submodule[len])
1898                 /* We need to strip off one or more trailing slashes */
1899                 submodule = to_free = xmemdupz(submodule, len);
1900
1901         refs = lookup_ref_store_map(&submodule_ref_stores, submodule);
1902         if (refs)
1903                 goto done;
1904
1905         strbuf_addstr(&submodule_sb, submodule);
1906         if (!is_nonbare_repository_dir(&submodule_sb))
1907                 goto done;
1908
1909         if (submodule_to_gitdir(&submodule_sb, submodule))
1910                 goto done;
1911
1912         /* assume that add_submodule_odb() has been called */
1913         refs = ref_store_init(submodule_sb.buf,
1914                               REF_STORE_READ | REF_STORE_ODB);
1915         register_ref_store_map(&submodule_ref_stores, "submodule",
1916                                refs, submodule);
1917
1918 done:
1919         strbuf_release(&submodule_sb);
1920         free(to_free);
1921
1922         return refs;
1923 }
1924
1925 struct ref_store *get_worktree_ref_store(const struct worktree *wt)
1926 {
1927         struct ref_store *refs;
1928         const char *id;
1929
1930         if (wt->is_current)
1931                 return get_main_ref_store(the_repository);
1932
1933         id = wt->id ? wt->id : "/";
1934         refs = lookup_ref_store_map(&worktree_ref_stores, id);
1935         if (refs)
1936                 return refs;
1937
1938         if (wt->id)
1939                 refs = ref_store_init(git_common_path("worktrees/%s", wt->id),
1940                                       REF_STORE_ALL_CAPS);
1941         else
1942                 refs = ref_store_init(get_git_common_dir(),
1943                                       REF_STORE_ALL_CAPS);
1944
1945         if (refs)
1946                 register_ref_store_map(&worktree_ref_stores, "worktree",
1947                                        refs, id);
1948         return refs;
1949 }
1950
1951 void base_ref_store_init(struct ref_store *refs,
1952                          const struct ref_storage_be *be)
1953 {
1954         refs->be = be;
1955 }
1956
1957 /* backend functions */
1958 int refs_pack_refs(struct ref_store *refs, unsigned int flags)
1959 {
1960         return refs->be->pack_refs(refs, flags);
1961 }
1962
1963 int refs_peel_ref(struct ref_store *refs, const char *refname,
1964                   struct object_id *oid)
1965 {
1966         int flag;
1967         struct object_id base;
1968
1969         if (current_ref_iter && current_ref_iter->refname == refname) {
1970                 struct object_id peeled;
1971
1972                 if (ref_iterator_peel(current_ref_iter, &peeled))
1973                         return -1;
1974                 oidcpy(oid, &peeled);
1975                 return 0;
1976         }
1977
1978         if (refs_read_ref_full(refs, refname,
1979                                RESOLVE_REF_READING, &base, &flag))
1980                 return -1;
1981
1982         return peel_object(&base, oid);
1983 }
1984
1985 int peel_ref(const char *refname, struct object_id *oid)
1986 {
1987         return refs_peel_ref(get_main_ref_store(the_repository), refname, oid);
1988 }
1989
1990 int refs_create_symref(struct ref_store *refs,
1991                        const char *ref_target,
1992                        const char *refs_heads_master,
1993                        const char *logmsg)
1994 {
1995         char *msg;
1996         int retval;
1997
1998         msg = normalize_reflog_message(logmsg);
1999         retval = refs->be->create_symref(refs, ref_target, refs_heads_master,
2000                                          msg);
2001         free(msg);
2002         return retval;
2003 }
2004
2005 int create_symref(const char *ref_target, const char *refs_heads_master,
2006                   const char *logmsg)
2007 {
2008         return refs_create_symref(get_main_ref_store(the_repository), ref_target,
2009                                   refs_heads_master, logmsg);
2010 }
2011
2012 int ref_update_reject_duplicates(struct string_list *refnames,
2013                                  struct strbuf *err)
2014 {
2015         size_t i, n = refnames->nr;
2016
2017         assert(err);
2018
2019         for (i = 1; i < n; i++) {
2020                 int cmp = strcmp(refnames->items[i - 1].string,
2021                                  refnames->items[i].string);
2022
2023                 if (!cmp) {
2024                         strbuf_addf(err,
2025                                     _("multiple updates for ref '%s' not allowed"),
2026                                     refnames->items[i].string);
2027                         return 1;
2028                 } else if (cmp > 0) {
2029                         BUG("ref_update_reject_duplicates() received unsorted list");
2030                 }
2031         }
2032         return 0;
2033 }
2034
2035 static const char hook_not_found;
2036 static const char *hook;
2037
2038 static int run_transaction_hook(struct ref_transaction *transaction,
2039                                 const char *state)
2040 {
2041         struct child_process proc = CHILD_PROCESS_INIT;
2042         struct strbuf buf = STRBUF_INIT;
2043         int ret = 0, i;
2044
2045         if (hook == &hook_not_found)
2046                 return ret;
2047         if (!hook)
2048                 hook = find_hook("reference-transaction");
2049         if (!hook) {
2050                 hook = &hook_not_found;
2051                 return ret;
2052         }
2053
2054         argv_array_pushl(&proc.args, hook, state, NULL);
2055         proc.in = -1;
2056         proc.stdout_to_stderr = 1;
2057         proc.trace2_hook_name = "reference-transaction";
2058
2059         ret = start_command(&proc);
2060         if (ret)
2061                 return ret;
2062
2063         sigchain_push(SIGPIPE, SIG_IGN);
2064
2065         for (i = 0; i < transaction->nr; i++) {
2066                 struct ref_update *update = transaction->updates[i];
2067
2068                 strbuf_reset(&buf);
2069                 strbuf_addf(&buf, "%s %s %s\n",
2070                             oid_to_hex(&update->old_oid),
2071                             oid_to_hex(&update->new_oid),
2072                             update->refname);
2073
2074                 if (write_in_full(proc.in, buf.buf, buf.len) < 0) {
2075                         if (errno != EPIPE)
2076                                 ret = -1;
2077                         break;
2078                 }
2079         }
2080
2081         close(proc.in);
2082         sigchain_pop(SIGPIPE);
2083         strbuf_release(&buf);
2084
2085         ret |= finish_command(&proc);
2086         return ret;
2087 }
2088
2089 int ref_transaction_prepare(struct ref_transaction *transaction,
2090                             struct strbuf *err)
2091 {
2092         struct ref_store *refs = transaction->ref_store;
2093         int ret;
2094
2095         switch (transaction->state) {
2096         case REF_TRANSACTION_OPEN:
2097                 /* Good. */
2098                 break;
2099         case REF_TRANSACTION_PREPARED:
2100                 BUG("prepare called twice on reference transaction");
2101                 break;
2102         case REF_TRANSACTION_CLOSED:
2103                 BUG("prepare called on a closed reference transaction");
2104                 break;
2105         default:
2106                 BUG("unexpected reference transaction state");
2107                 break;
2108         }
2109
2110         if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
2111                 strbuf_addstr(err,
2112                               _("ref updates forbidden inside quarantine environment"));
2113                 return -1;
2114         }
2115
2116         ret = refs->be->transaction_prepare(refs, transaction, err);
2117         if (ret)
2118                 return ret;
2119
2120         ret = run_transaction_hook(transaction, "prepared");
2121         if (ret) {
2122                 ref_transaction_abort(transaction, err);
2123                 die(_("ref updates aborted by hook"));
2124         }
2125
2126         return 0;
2127 }
2128
2129 int ref_transaction_abort(struct ref_transaction *transaction,
2130                           struct strbuf *err)
2131 {
2132         struct ref_store *refs = transaction->ref_store;
2133         int ret = 0;
2134
2135         switch (transaction->state) {
2136         case REF_TRANSACTION_OPEN:
2137                 /* No need to abort explicitly. */
2138                 break;
2139         case REF_TRANSACTION_PREPARED:
2140                 ret = refs->be->transaction_abort(refs, transaction, err);
2141                 break;
2142         case REF_TRANSACTION_CLOSED:
2143                 BUG("abort called on a closed reference transaction");
2144                 break;
2145         default:
2146                 BUG("unexpected reference transaction state");
2147                 break;
2148         }
2149
2150         run_transaction_hook(transaction, "aborted");
2151
2152         ref_transaction_free(transaction);
2153         return ret;
2154 }
2155
2156 int ref_transaction_commit(struct ref_transaction *transaction,
2157                            struct strbuf *err)
2158 {
2159         struct ref_store *refs = transaction->ref_store;
2160         int ret;
2161
2162         switch (transaction->state) {
2163         case REF_TRANSACTION_OPEN:
2164                 /* Need to prepare first. */
2165                 ret = ref_transaction_prepare(transaction, err);
2166                 if (ret)
2167                         return ret;
2168                 break;
2169         case REF_TRANSACTION_PREPARED:
2170                 /* Fall through to finish. */
2171                 break;
2172         case REF_TRANSACTION_CLOSED:
2173                 BUG("commit called on a closed reference transaction");
2174                 break;
2175         default:
2176                 BUG("unexpected reference transaction state");
2177                 break;
2178         }
2179
2180         ret = refs->be->transaction_finish(refs, transaction, err);
2181         if (!ret)
2182                 run_transaction_hook(transaction, "committed");
2183         return ret;
2184 }
2185
2186 int refs_verify_refname_available(struct ref_store *refs,
2187                                   const char *refname,
2188                                   const struct string_list *extras,
2189                                   const struct string_list *skip,
2190                                   struct strbuf *err)
2191 {
2192         const char *slash;
2193         const char *extra_refname;
2194         struct strbuf dirname = STRBUF_INIT;
2195         struct strbuf referent = STRBUF_INIT;
2196         struct object_id oid;
2197         unsigned int type;
2198         struct ref_iterator *iter;
2199         int ok;
2200         int ret = -1;
2201
2202         /*
2203          * For the sake of comments in this function, suppose that
2204          * refname is "refs/foo/bar".
2205          */
2206
2207         assert(err);
2208
2209         strbuf_grow(&dirname, strlen(refname) + 1);
2210         for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
2211                 /* Expand dirname to the new prefix, not including the trailing slash: */
2212                 strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
2213
2214                 /*
2215                  * We are still at a leading dir of the refname (e.g.,
2216                  * "refs/foo"; if there is a reference with that name,
2217                  * it is a conflict, *unless* it is in skip.
2218                  */
2219                 if (skip && string_list_has_string(skip, dirname.buf))
2220                         continue;
2221
2222                 if (!refs_read_raw_ref(refs, dirname.buf, &oid, &referent, &type)) {
2223                         strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
2224                                     dirname.buf, refname);
2225                         goto cleanup;
2226                 }
2227
2228                 if (extras && string_list_has_string(extras, dirname.buf)) {
2229                         strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
2230                                     refname, dirname.buf);
2231                         goto cleanup;
2232                 }
2233         }
2234
2235         /*
2236          * We are at the leaf of our refname (e.g., "refs/foo/bar").
2237          * There is no point in searching for a reference with that
2238          * name, because a refname isn't considered to conflict with
2239          * itself. But we still need to check for references whose
2240          * names are in the "refs/foo/bar/" namespace, because they
2241          * *do* conflict.
2242          */
2243         strbuf_addstr(&dirname, refname + dirname.len);
2244         strbuf_addch(&dirname, '/');
2245
2246         iter = refs_ref_iterator_begin(refs, dirname.buf, 0,
2247                                        DO_FOR_EACH_INCLUDE_BROKEN);
2248         while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
2249                 if (skip &&
2250                     string_list_has_string(skip, iter->refname))
2251                         continue;
2252
2253                 strbuf_addf(err, _("'%s' exists; cannot create '%s'"),
2254                             iter->refname, refname);
2255                 ref_iterator_abort(iter);
2256                 goto cleanup;
2257         }
2258
2259         if (ok != ITER_DONE)
2260                 BUG("error while iterating over references");
2261
2262         extra_refname = find_descendant_ref(dirname.buf, extras, skip);
2263         if (extra_refname)
2264                 strbuf_addf(err, _("cannot process '%s' and '%s' at the same time"),
2265                             refname, extra_refname);
2266         else
2267                 ret = 0;
2268
2269 cleanup:
2270         strbuf_release(&referent);
2271         strbuf_release(&dirname);
2272         return ret;
2273 }
2274
2275 int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2276 {
2277         struct ref_iterator *iter;
2278         struct do_for_each_ref_help hp = { fn, cb_data };
2279
2280         iter = refs->be->reflog_iterator_begin(refs);
2281
2282         return do_for_each_repo_ref_iterator(the_repository, iter,
2283                                              do_for_each_ref_helper, &hp);
2284 }
2285
2286 int for_each_reflog(each_ref_fn fn, void *cb_data)
2287 {
2288         return refs_for_each_reflog(get_main_ref_store(the_repository), fn, cb_data);
2289 }
2290
2291 int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
2292                                      const char *refname,
2293                                      each_reflog_ent_fn fn,
2294                                      void *cb_data)
2295 {
2296         return refs->be->for_each_reflog_ent_reverse(refs, refname,
2297                                                      fn, cb_data);
2298 }
2299
2300 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
2301                                 void *cb_data)
2302 {
2303         return refs_for_each_reflog_ent_reverse(get_main_ref_store(the_repository),
2304                                                 refname, fn, cb_data);
2305 }
2306
2307 int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
2308                              each_reflog_ent_fn fn, void *cb_data)
2309 {
2310         return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
2311 }
2312
2313 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
2314                         void *cb_data)
2315 {
2316         return refs_for_each_reflog_ent(get_main_ref_store(the_repository), refname,
2317                                         fn, cb_data);
2318 }
2319
2320 int refs_reflog_exists(struct ref_store *refs, const char *refname)
2321 {
2322         return refs->be->reflog_exists(refs, refname);
2323 }
2324
2325 int reflog_exists(const char *refname)
2326 {
2327         return refs_reflog_exists(get_main_ref_store(the_repository), refname);
2328 }
2329
2330 int refs_create_reflog(struct ref_store *refs, const char *refname,
2331                        int force_create, struct strbuf *err)
2332 {
2333         return refs->be->create_reflog(refs, refname, force_create, err);
2334 }
2335
2336 int safe_create_reflog(const char *refname, int force_create,
2337                        struct strbuf *err)
2338 {
2339         return refs_create_reflog(get_main_ref_store(the_repository), refname,
2340                                   force_create, err);
2341 }
2342
2343 int refs_delete_reflog(struct ref_store *refs, const char *refname)
2344 {
2345         return refs->be->delete_reflog(refs, refname);
2346 }
2347
2348 int delete_reflog(const char *refname)
2349 {
2350         return refs_delete_reflog(get_main_ref_store(the_repository), refname);
2351 }
2352
2353 int refs_reflog_expire(struct ref_store *refs,
2354                        const char *refname, const struct object_id *oid,
2355                        unsigned int flags,
2356                        reflog_expiry_prepare_fn prepare_fn,
2357                        reflog_expiry_should_prune_fn should_prune_fn,
2358                        reflog_expiry_cleanup_fn cleanup_fn,
2359                        void *policy_cb_data)
2360 {
2361         return refs->be->reflog_expire(refs, refname, oid, flags,
2362                                        prepare_fn, should_prune_fn,
2363                                        cleanup_fn, policy_cb_data);
2364 }
2365
2366 int reflog_expire(const char *refname, const struct object_id *oid,
2367                   unsigned int flags,
2368                   reflog_expiry_prepare_fn prepare_fn,
2369                   reflog_expiry_should_prune_fn should_prune_fn,
2370                   reflog_expiry_cleanup_fn cleanup_fn,
2371                   void *policy_cb_data)
2372 {
2373         return refs_reflog_expire(get_main_ref_store(the_repository),
2374                                   refname, oid, flags,
2375                                   prepare_fn, should_prune_fn,
2376                                   cleanup_fn, policy_cb_data);
2377 }
2378
2379 int initial_ref_transaction_commit(struct ref_transaction *transaction,
2380                                    struct strbuf *err)
2381 {
2382         struct ref_store *refs = transaction->ref_store;
2383
2384         return refs->be->initial_transaction_commit(refs, transaction, err);
2385 }
2386
2387 int refs_delete_refs(struct ref_store *refs, const char *logmsg,
2388                      struct string_list *refnames, unsigned int flags)
2389 {
2390         char *msg;
2391         int retval;
2392
2393         msg = normalize_reflog_message(logmsg);
2394         retval = refs->be->delete_refs(refs, msg, refnames, flags);
2395         free(msg);
2396         return retval;
2397 }
2398
2399 int delete_refs(const char *msg, struct string_list *refnames,
2400                 unsigned int flags)
2401 {
2402         return refs_delete_refs(get_main_ref_store(the_repository), msg, refnames, flags);
2403 }
2404
2405 int refs_rename_ref(struct ref_store *refs, const char *oldref,
2406                     const char *newref, const char *logmsg)
2407 {
2408         char *msg;
2409         int retval;
2410
2411         msg = normalize_reflog_message(logmsg);
2412         retval = refs->be->rename_ref(refs, oldref, newref, msg);
2413         free(msg);
2414         return retval;
2415 }
2416
2417 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
2418 {
2419         return refs_rename_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
2420 }
2421
2422 int refs_copy_existing_ref(struct ref_store *refs, const char *oldref,
2423                     const char *newref, const char *logmsg)
2424 {
2425         char *msg;
2426         int retval;
2427
2428         msg = normalize_reflog_message(logmsg);
2429         retval = refs->be->copy_ref(refs, oldref, newref, msg);
2430         free(msg);
2431         return retval;
2432 }
2433
2434 int copy_existing_ref(const char *oldref, const char *newref, const char *logmsg)
2435 {
2436         return refs_copy_existing_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
2437 }