Merge branch 'jc/am-i-v-fix' into maint
[git] / refs.c
1 /*
2  * The backend-independent part of the reference module.
3  */
4
5 #include "cache.h"
6 #include "lockfile.h"
7 #include "refs.h"
8 #include "refs/refs-internal.h"
9 #include "object.h"
10 #include "tag.h"
11
12 /*
13  * How to handle various characters in refnames:
14  * 0: An acceptable character for refs
15  * 1: End-of-component
16  * 2: ., look for a preceding . to reject .. in refs
17  * 3: {, look for a preceding @ to reject @{ in refs
18  * 4: A bad character: ASCII control characters, and
19  *    ":", "?", "[", "\", "^", "~", SP, or TAB
20  * 5: *, reject unless REFNAME_REFSPEC_PATTERN is set
21  */
22 static unsigned char refname_disposition[256] = {
23         1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
24         4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
25         4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 1,
26         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4,
27         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
28         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 4, 0,
29         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
30         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
31 };
32
33 /*
34  * Try to read one refname component from the front of refname.
35  * Return the length of the component found, or -1 if the component is
36  * not legal.  It is legal if it is something reasonable to have under
37  * ".git/refs/"; We do not like it if:
38  *
39  * - any path component of it begins with ".", or
40  * - it has double dots "..", or
41  * - it has ASCII control characters, or
42  * - it has ":", "?", "[", "\", "^", "~", SP, or TAB anywhere, or
43  * - it has "*" anywhere unless REFNAME_REFSPEC_PATTERN is set, or
44  * - it ends with a "/", or
45  * - it ends with ".lock", or
46  * - it contains a "@{" portion
47  */
48 static int check_refname_component(const char *refname, int *flags)
49 {
50         const char *cp;
51         char last = '\0';
52
53         for (cp = refname; ; cp++) {
54                 int ch = *cp & 255;
55                 unsigned char disp = refname_disposition[ch];
56                 switch (disp) {
57                 case 1:
58                         goto out;
59                 case 2:
60                         if (last == '.')
61                                 return -1; /* Refname contains "..". */
62                         break;
63                 case 3:
64                         if (last == '@')
65                                 return -1; /* Refname contains "@{". */
66                         break;
67                 case 4:
68                         return -1;
69                 case 5:
70                         if (!(*flags & REFNAME_REFSPEC_PATTERN))
71                                 return -1; /* refspec can't be a pattern */
72
73                         /*
74                          * Unset the pattern flag so that we only accept
75                          * a single asterisk for one side of refspec.
76                          */
77                         *flags &= ~ REFNAME_REFSPEC_PATTERN;
78                         break;
79                 }
80                 last = ch;
81         }
82 out:
83         if (cp == refname)
84                 return 0; /* Component has zero length. */
85         if (refname[0] == '.')
86                 return -1; /* Component starts with '.'. */
87         if (cp - refname >= LOCK_SUFFIX_LEN &&
88             !memcmp(cp - LOCK_SUFFIX_LEN, LOCK_SUFFIX, LOCK_SUFFIX_LEN))
89                 return -1; /* Refname ends with ".lock". */
90         return cp - refname;
91 }
92
93 int check_refname_format(const char *refname, int flags)
94 {
95         int component_len, component_count = 0;
96
97         if (!strcmp(refname, "@"))
98                 /* Refname is a single character '@'. */
99                 return -1;
100
101         while (1) {
102                 /* We are at the start of a path component. */
103                 component_len = check_refname_component(refname, &flags);
104                 if (component_len <= 0)
105                         return -1;
106
107                 component_count++;
108                 if (refname[component_len] == '\0')
109                         break;
110                 /* Skip to next component. */
111                 refname += component_len + 1;
112         }
113
114         if (refname[component_len - 1] == '.')
115                 return -1; /* Refname ends with '.'. */
116         if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
117                 return -1; /* Refname has only one component. */
118         return 0;
119 }
120
121 int refname_is_safe(const char *refname)
122 {
123         if (starts_with(refname, "refs/")) {
124                 char *buf;
125                 int result;
126
127                 buf = xmalloc(strlen(refname) + 1);
128                 /*
129                  * Does the refname try to escape refs/?
130                  * For example: refs/foo/../bar is safe but refs/foo/../../bar
131                  * is not.
132                  */
133                 result = !normalize_path_copy(buf, refname + strlen("refs/"));
134                 free(buf);
135                 return result;
136         }
137         while (*refname) {
138                 if (!isupper(*refname) && *refname != '_')
139                         return 0;
140                 refname++;
141         }
142         return 1;
143 }
144
145 char *resolve_refdup(const char *refname, int resolve_flags,
146                      unsigned char *sha1, int *flags)
147 {
148         return xstrdup_or_null(resolve_ref_unsafe(refname, resolve_flags,
149                                                   sha1, flags));
150 }
151
152 /* The argument to filter_refs */
153 struct ref_filter {
154         const char *pattern;
155         each_ref_fn *fn;
156         void *cb_data;
157 };
158
159 int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
160 {
161         if (resolve_ref_unsafe(refname, resolve_flags, sha1, flags))
162                 return 0;
163         return -1;
164 }
165
166 int read_ref(const char *refname, unsigned char *sha1)
167 {
168         return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
169 }
170
171 int ref_exists(const char *refname)
172 {
173         unsigned char sha1[20];
174         return !!resolve_ref_unsafe(refname, RESOLVE_REF_READING, sha1, NULL);
175 }
176
177 static int filter_refs(const char *refname, const struct object_id *oid,
178                            int flags, void *data)
179 {
180         struct ref_filter *filter = (struct ref_filter *)data;
181
182         if (wildmatch(filter->pattern, refname, 0, NULL))
183                 return 0;
184         return filter->fn(refname, oid, flags, filter->cb_data);
185 }
186
187 enum peel_status peel_object(const unsigned char *name, unsigned char *sha1)
188 {
189         struct object *o = lookup_unknown_object(name);
190
191         if (o->type == OBJ_NONE) {
192                 int type = sha1_object_info(name, NULL);
193                 if (type < 0 || !object_as_type(o, type, 0))
194                         return PEEL_INVALID;
195         }
196
197         if (o->type != OBJ_TAG)
198                 return PEEL_NON_TAG;
199
200         o = deref_tag_noverify(o);
201         if (!o)
202                 return PEEL_INVALID;
203
204         hashcpy(sha1, o->oid.hash);
205         return PEEL_PEELED;
206 }
207
208 struct warn_if_dangling_data {
209         FILE *fp;
210         const char *refname;
211         const struct string_list *refnames;
212         const char *msg_fmt;
213 };
214
215 static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
216                                    int flags, void *cb_data)
217 {
218         struct warn_if_dangling_data *d = cb_data;
219         const char *resolves_to;
220         struct object_id junk;
221
222         if (!(flags & REF_ISSYMREF))
223                 return 0;
224
225         resolves_to = resolve_ref_unsafe(refname, 0, junk.hash, NULL);
226         if (!resolves_to
227             || (d->refname
228                 ? strcmp(resolves_to, d->refname)
229                 : !string_list_has_string(d->refnames, resolves_to))) {
230                 return 0;
231         }
232
233         fprintf(d->fp, d->msg_fmt, refname);
234         fputc('\n', d->fp);
235         return 0;
236 }
237
238 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
239 {
240         struct warn_if_dangling_data data;
241
242         data.fp = fp;
243         data.refname = refname;
244         data.refnames = NULL;
245         data.msg_fmt = msg_fmt;
246         for_each_rawref(warn_if_dangling_symref, &data);
247 }
248
249 void warn_dangling_symrefs(FILE *fp, const char *msg_fmt, const struct string_list *refnames)
250 {
251         struct warn_if_dangling_data data;
252
253         data.fp = fp;
254         data.refname = NULL;
255         data.refnames = refnames;
256         data.msg_fmt = msg_fmt;
257         for_each_rawref(warn_if_dangling_symref, &data);
258 }
259
260 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
261 {
262         return for_each_ref_in("refs/tags/", fn, cb_data);
263 }
264
265 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
266 {
267         return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
268 }
269
270 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
271 {
272         return for_each_ref_in("refs/heads/", fn, cb_data);
273 }
274
275 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
276 {
277         return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
278 }
279
280 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
281 {
282         return for_each_ref_in("refs/remotes/", fn, cb_data);
283 }
284
285 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
286 {
287         return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
288 }
289
290 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
291 {
292         struct strbuf buf = STRBUF_INIT;
293         int ret = 0;
294         struct object_id oid;
295         int flag;
296
297         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
298         if (!read_ref_full(buf.buf, RESOLVE_REF_READING, oid.hash, &flag))
299                 ret = fn(buf.buf, &oid, flag, cb_data);
300         strbuf_release(&buf);
301
302         return ret;
303 }
304
305 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
306         const char *prefix, void *cb_data)
307 {
308         struct strbuf real_pattern = STRBUF_INIT;
309         struct ref_filter filter;
310         int ret;
311
312         if (!prefix && !starts_with(pattern, "refs/"))
313                 strbuf_addstr(&real_pattern, "refs/");
314         else if (prefix)
315                 strbuf_addstr(&real_pattern, prefix);
316         strbuf_addstr(&real_pattern, pattern);
317
318         if (!has_glob_specials(pattern)) {
319                 /* Append implied '/' '*' if not present. */
320                 strbuf_complete(&real_pattern, '/');
321                 /* No need to check for '*', there is none. */
322                 strbuf_addch(&real_pattern, '*');
323         }
324
325         filter.pattern = real_pattern.buf;
326         filter.fn = fn;
327         filter.cb_data = cb_data;
328         ret = for_each_ref(filter_refs, &filter);
329
330         strbuf_release(&real_pattern);
331         return ret;
332 }
333
334 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
335 {
336         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
337 }
338
339 const char *prettify_refname(const char *name)
340 {
341         return name + (
342                 starts_with(name, "refs/heads/") ? 11 :
343                 starts_with(name, "refs/tags/") ? 10 :
344                 starts_with(name, "refs/remotes/") ? 13 :
345                 0);
346 }
347
348 static const char *ref_rev_parse_rules[] = {
349         "%.*s",
350         "refs/%.*s",
351         "refs/tags/%.*s",
352         "refs/heads/%.*s",
353         "refs/remotes/%.*s",
354         "refs/remotes/%.*s/HEAD",
355         NULL
356 };
357
358 int refname_match(const char *abbrev_name, const char *full_name)
359 {
360         const char **p;
361         const int abbrev_name_len = strlen(abbrev_name);
362
363         for (p = ref_rev_parse_rules; *p; p++) {
364                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
365                         return 1;
366                 }
367         }
368
369         return 0;
370 }
371
372 /*
373  * *string and *len will only be substituted, and *string returned (for
374  * later free()ing) if the string passed in is a magic short-hand form
375  * to name a branch.
376  */
377 static char *substitute_branch_name(const char **string, int *len)
378 {
379         struct strbuf buf = STRBUF_INIT;
380         int ret = interpret_branch_name(*string, *len, &buf);
381
382         if (ret == *len) {
383                 size_t size;
384                 *string = strbuf_detach(&buf, &size);
385                 *len = size;
386                 return (char *)*string;
387         }
388
389         return NULL;
390 }
391
392 int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
393 {
394         char *last_branch = substitute_branch_name(&str, &len);
395         const char **p, *r;
396         int refs_found = 0;
397
398         *ref = NULL;
399         for (p = ref_rev_parse_rules; *p; p++) {
400                 char fullref[PATH_MAX];
401                 unsigned char sha1_from_ref[20];
402                 unsigned char *this_result;
403                 int flag;
404
405                 this_result = refs_found ? sha1_from_ref : sha1;
406                 mksnpath(fullref, sizeof(fullref), *p, len, str);
407                 r = resolve_ref_unsafe(fullref, RESOLVE_REF_READING,
408                                        this_result, &flag);
409                 if (r) {
410                         if (!refs_found++)
411                                 *ref = xstrdup(r);
412                         if (!warn_ambiguous_refs)
413                                 break;
414                 } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
415                         warning("ignoring dangling symref %s.", fullref);
416                 } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
417                         warning("ignoring broken ref %s.", fullref);
418                 }
419         }
420         free(last_branch);
421         return refs_found;
422 }
423
424 int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
425 {
426         char *last_branch = substitute_branch_name(&str, &len);
427         const char **p;
428         int logs_found = 0;
429
430         *log = NULL;
431         for (p = ref_rev_parse_rules; *p; p++) {
432                 unsigned char hash[20];
433                 char path[PATH_MAX];
434                 const char *ref, *it;
435
436                 mksnpath(path, sizeof(path), *p, len, str);
437                 ref = resolve_ref_unsafe(path, RESOLVE_REF_READING,
438                                          hash, NULL);
439                 if (!ref)
440                         continue;
441                 if (reflog_exists(path))
442                         it = path;
443                 else if (strcmp(ref, path) && reflog_exists(ref))
444                         it = ref;
445                 else
446                         continue;
447                 if (!logs_found++) {
448                         *log = xstrdup(it);
449                         hashcpy(sha1, hash);
450                 }
451                 if (!warn_ambiguous_refs)
452                         break;
453         }
454         free(last_branch);
455         return logs_found;
456 }
457
458 static int is_per_worktree_ref(const char *refname)
459 {
460         return !strcmp(refname, "HEAD") ||
461                 starts_with(refname, "refs/bisect/");
462 }
463
464 static int is_pseudoref_syntax(const char *refname)
465 {
466         const char *c;
467
468         for (c = refname; *c; c++) {
469                 if (!isupper(*c) && *c != '-' && *c != '_')
470                         return 0;
471         }
472
473         return 1;
474 }
475
476 enum ref_type ref_type(const char *refname)
477 {
478         if (is_per_worktree_ref(refname))
479                 return REF_TYPE_PER_WORKTREE;
480         if (is_pseudoref_syntax(refname))
481                 return REF_TYPE_PSEUDOREF;
482        return REF_TYPE_NORMAL;
483 }
484
485 static int write_pseudoref(const char *pseudoref, const unsigned char *sha1,
486                            const unsigned char *old_sha1, struct strbuf *err)
487 {
488         const char *filename;
489         int fd;
490         static struct lock_file lock;
491         struct strbuf buf = STRBUF_INIT;
492         int ret = -1;
493
494         strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
495
496         filename = git_path("%s", pseudoref);
497         fd = hold_lock_file_for_update(&lock, filename, LOCK_DIE_ON_ERROR);
498         if (fd < 0) {
499                 strbuf_addf(err, "Could not open '%s' for writing: %s",
500                             filename, strerror(errno));
501                 return -1;
502         }
503
504         if (old_sha1) {
505                 unsigned char actual_old_sha1[20];
506
507                 if (read_ref(pseudoref, actual_old_sha1))
508                         die("could not read ref '%s'", pseudoref);
509                 if (hashcmp(actual_old_sha1, old_sha1)) {
510                         strbuf_addf(err, "Unexpected sha1 when writing %s", pseudoref);
511                         rollback_lock_file(&lock);
512                         goto done;
513                 }
514         }
515
516         if (write_in_full(fd, buf.buf, buf.len) != buf.len) {
517                 strbuf_addf(err, "Could not write to '%s'", filename);
518                 rollback_lock_file(&lock);
519                 goto done;
520         }
521
522         commit_lock_file(&lock);
523         ret = 0;
524 done:
525         strbuf_release(&buf);
526         return ret;
527 }
528
529 static int delete_pseudoref(const char *pseudoref, const unsigned char *old_sha1)
530 {
531         static struct lock_file lock;
532         const char *filename;
533
534         filename = git_path("%s", pseudoref);
535
536         if (old_sha1 && !is_null_sha1(old_sha1)) {
537                 int fd;
538                 unsigned char actual_old_sha1[20];
539
540                 fd = hold_lock_file_for_update(&lock, filename,
541                                                LOCK_DIE_ON_ERROR);
542                 if (fd < 0)
543                         die_errno(_("Could not open '%s' for writing"), filename);
544                 if (read_ref(pseudoref, actual_old_sha1))
545                         die("could not read ref '%s'", pseudoref);
546                 if (hashcmp(actual_old_sha1, old_sha1)) {
547                         warning("Unexpected sha1 when deleting %s", pseudoref);
548                         rollback_lock_file(&lock);
549                         return -1;
550                 }
551
552                 unlink(filename);
553                 rollback_lock_file(&lock);
554         } else {
555                 unlink(filename);
556         }
557
558         return 0;
559 }
560
561 int delete_ref(const char *refname, const unsigned char *old_sha1,
562                unsigned int flags)
563 {
564         struct ref_transaction *transaction;
565         struct strbuf err = STRBUF_INIT;
566
567         if (ref_type(refname) == REF_TYPE_PSEUDOREF)
568                 return delete_pseudoref(refname, old_sha1);
569
570         transaction = ref_transaction_begin(&err);
571         if (!transaction ||
572             ref_transaction_delete(transaction, refname, old_sha1,
573                                    flags, NULL, &err) ||
574             ref_transaction_commit(transaction, &err)) {
575                 error("%s", err.buf);
576                 ref_transaction_free(transaction);
577                 strbuf_release(&err);
578                 return 1;
579         }
580         ref_transaction_free(transaction);
581         strbuf_release(&err);
582         return 0;
583 }
584
585 int copy_reflog_msg(char *buf, const char *msg)
586 {
587         char *cp = buf;
588         char c;
589         int wasspace = 1;
590
591         *cp++ = '\t';
592         while ((c = *msg++)) {
593                 if (wasspace && isspace(c))
594                         continue;
595                 wasspace = isspace(c);
596                 if (wasspace)
597                         c = ' ';
598                 *cp++ = c;
599         }
600         while (buf < cp && isspace(cp[-1]))
601                 cp--;
602         *cp++ = '\n';
603         return cp - buf;
604 }
605
606 int should_autocreate_reflog(const char *refname)
607 {
608         if (!log_all_ref_updates)
609                 return 0;
610         return starts_with(refname, "refs/heads/") ||
611                 starts_with(refname, "refs/remotes/") ||
612                 starts_with(refname, "refs/notes/") ||
613                 !strcmp(refname, "HEAD");
614 }
615
616 int is_branch(const char *refname)
617 {
618         return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
619 }
620
621 struct read_ref_at_cb {
622         const char *refname;
623         unsigned long at_time;
624         int cnt;
625         int reccnt;
626         unsigned char *sha1;
627         int found_it;
628
629         unsigned char osha1[20];
630         unsigned char nsha1[20];
631         int tz;
632         unsigned long date;
633         char **msg;
634         unsigned long *cutoff_time;
635         int *cutoff_tz;
636         int *cutoff_cnt;
637 };
638
639 static int read_ref_at_ent(unsigned char *osha1, unsigned char *nsha1,
640                 const char *email, unsigned long timestamp, int tz,
641                 const char *message, void *cb_data)
642 {
643         struct read_ref_at_cb *cb = cb_data;
644
645         cb->reccnt++;
646         cb->tz = tz;
647         cb->date = timestamp;
648
649         if (timestamp <= cb->at_time || cb->cnt == 0) {
650                 if (cb->msg)
651                         *cb->msg = xstrdup(message);
652                 if (cb->cutoff_time)
653                         *cb->cutoff_time = timestamp;
654                 if (cb->cutoff_tz)
655                         *cb->cutoff_tz = tz;
656                 if (cb->cutoff_cnt)
657                         *cb->cutoff_cnt = cb->reccnt - 1;
658                 /*
659                  * we have not yet updated cb->[n|o]sha1 so they still
660                  * hold the values for the previous record.
661                  */
662                 if (!is_null_sha1(cb->osha1)) {
663                         hashcpy(cb->sha1, nsha1);
664                         if (hashcmp(cb->osha1, nsha1))
665                                 warning("Log for ref %s has gap after %s.",
666                                         cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
667                 }
668                 else if (cb->date == cb->at_time)
669                         hashcpy(cb->sha1, nsha1);
670                 else if (hashcmp(nsha1, cb->sha1))
671                         warning("Log for ref %s unexpectedly ended on %s.",
672                                 cb->refname, show_date(cb->date, cb->tz,
673                                                        DATE_MODE(RFC2822)));
674                 hashcpy(cb->osha1, osha1);
675                 hashcpy(cb->nsha1, nsha1);
676                 cb->found_it = 1;
677                 return 1;
678         }
679         hashcpy(cb->osha1, osha1);
680         hashcpy(cb->nsha1, nsha1);
681         if (cb->cnt > 0)
682                 cb->cnt--;
683         return 0;
684 }
685
686 static int read_ref_at_ent_oldest(unsigned char *osha1, unsigned char *nsha1,
687                                   const char *email, unsigned long timestamp,
688                                   int tz, const char *message, void *cb_data)
689 {
690         struct read_ref_at_cb *cb = cb_data;
691
692         if (cb->msg)
693                 *cb->msg = xstrdup(message);
694         if (cb->cutoff_time)
695                 *cb->cutoff_time = timestamp;
696         if (cb->cutoff_tz)
697                 *cb->cutoff_tz = tz;
698         if (cb->cutoff_cnt)
699                 *cb->cutoff_cnt = cb->reccnt;
700         hashcpy(cb->sha1, osha1);
701         if (is_null_sha1(cb->sha1))
702                 hashcpy(cb->sha1, nsha1);
703         /* We just want the first entry */
704         return 1;
705 }
706
707 int read_ref_at(const char *refname, unsigned int flags, unsigned long at_time, int cnt,
708                 unsigned char *sha1, char **msg,
709                 unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
710 {
711         struct read_ref_at_cb cb;
712
713         memset(&cb, 0, sizeof(cb));
714         cb.refname = refname;
715         cb.at_time = at_time;
716         cb.cnt = cnt;
717         cb.msg = msg;
718         cb.cutoff_time = cutoff_time;
719         cb.cutoff_tz = cutoff_tz;
720         cb.cutoff_cnt = cutoff_cnt;
721         cb.sha1 = sha1;
722
723         for_each_reflog_ent_reverse(refname, read_ref_at_ent, &cb);
724
725         if (!cb.reccnt) {
726                 if (flags & GET_SHA1_QUIETLY)
727                         exit(128);
728                 else
729                         die("Log for %s is empty.", refname);
730         }
731         if (cb.found_it)
732                 return 0;
733
734         for_each_reflog_ent(refname, read_ref_at_ent_oldest, &cb);
735
736         return 1;
737 }
738
739 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
740 {
741         assert(err);
742
743         return xcalloc(1, sizeof(struct ref_transaction));
744 }
745
746 void ref_transaction_free(struct ref_transaction *transaction)
747 {
748         int i;
749
750         if (!transaction)
751                 return;
752
753         for (i = 0; i < transaction->nr; i++) {
754                 free(transaction->updates[i]->msg);
755                 free(transaction->updates[i]);
756         }
757         free(transaction->updates);
758         free(transaction);
759 }
760
761 static struct ref_update *add_update(struct ref_transaction *transaction,
762                                      const char *refname)
763 {
764         size_t len = strlen(refname) + 1;
765         struct ref_update *update = xcalloc(1, sizeof(*update) + len);
766
767         memcpy((char *)update->refname, refname, len); /* includes NUL */
768         ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
769         transaction->updates[transaction->nr++] = update;
770         return update;
771 }
772
773 int ref_transaction_update(struct ref_transaction *transaction,
774                            const char *refname,
775                            const unsigned char *new_sha1,
776                            const unsigned char *old_sha1,
777                            unsigned int flags, const char *msg,
778                            struct strbuf *err)
779 {
780         struct ref_update *update;
781
782         assert(err);
783
784         if (transaction->state != REF_TRANSACTION_OPEN)
785                 die("BUG: update called for transaction that is not open");
786
787         if (new_sha1 && !is_null_sha1(new_sha1) &&
788             check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
789                 strbuf_addf(err, "refusing to update ref with bad name %s",
790                             refname);
791                 return -1;
792         }
793
794         update = add_update(transaction, refname);
795         if (new_sha1) {
796                 hashcpy(update->new_sha1, new_sha1);
797                 flags |= REF_HAVE_NEW;
798         }
799         if (old_sha1) {
800                 hashcpy(update->old_sha1, old_sha1);
801                 flags |= REF_HAVE_OLD;
802         }
803         update->flags = flags;
804         if (msg)
805                 update->msg = xstrdup(msg);
806         return 0;
807 }
808
809 int ref_transaction_create(struct ref_transaction *transaction,
810                            const char *refname,
811                            const unsigned char *new_sha1,
812                            unsigned int flags, const char *msg,
813                            struct strbuf *err)
814 {
815         if (!new_sha1 || is_null_sha1(new_sha1))
816                 die("BUG: create called without valid new_sha1");
817         return ref_transaction_update(transaction, refname, new_sha1,
818                                       null_sha1, flags, msg, err);
819 }
820
821 int ref_transaction_delete(struct ref_transaction *transaction,
822                            const char *refname,
823                            const unsigned char *old_sha1,
824                            unsigned int flags, const char *msg,
825                            struct strbuf *err)
826 {
827         if (old_sha1 && is_null_sha1(old_sha1))
828                 die("BUG: delete called with old_sha1 set to zeros");
829         return ref_transaction_update(transaction, refname,
830                                       null_sha1, old_sha1,
831                                       flags, msg, err);
832 }
833
834 int ref_transaction_verify(struct ref_transaction *transaction,
835                            const char *refname,
836                            const unsigned char *old_sha1,
837                            unsigned int flags,
838                            struct strbuf *err)
839 {
840         if (!old_sha1)
841                 die("BUG: verify called with old_sha1 set to NULL");
842         return ref_transaction_update(transaction, refname,
843                                       NULL, old_sha1,
844                                       flags, NULL, err);
845 }
846
847 int update_ref(const char *msg, const char *refname,
848                const unsigned char *new_sha1, const unsigned char *old_sha1,
849                unsigned int flags, enum action_on_err onerr)
850 {
851         struct ref_transaction *t = NULL;
852         struct strbuf err = STRBUF_INIT;
853         int ret = 0;
854
855         if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
856                 ret = write_pseudoref(refname, new_sha1, old_sha1, &err);
857         } else {
858                 t = ref_transaction_begin(&err);
859                 if (!t ||
860                     ref_transaction_update(t, refname, new_sha1, old_sha1,
861                                            flags, msg, &err) ||
862                     ref_transaction_commit(t, &err)) {
863                         ret = 1;
864                         ref_transaction_free(t);
865                 }
866         }
867         if (ret) {
868                 const char *str = "update_ref failed for ref '%s': %s";
869
870                 switch (onerr) {
871                 case UPDATE_REFS_MSG_ON_ERR:
872                         error(str, refname, err.buf);
873                         break;
874                 case UPDATE_REFS_DIE_ON_ERR:
875                         die(str, refname, err.buf);
876                         break;
877                 case UPDATE_REFS_QUIET_ON_ERR:
878                         break;
879                 }
880                 strbuf_release(&err);
881                 return 1;
882         }
883         strbuf_release(&err);
884         if (t)
885                 ref_transaction_free(t);
886         return 0;
887 }
888
889 char *shorten_unambiguous_ref(const char *refname, int strict)
890 {
891         int i;
892         static char **scanf_fmts;
893         static int nr_rules;
894         char *short_name;
895
896         if (!nr_rules) {
897                 /*
898                  * Pre-generate scanf formats from ref_rev_parse_rules[].
899                  * Generate a format suitable for scanf from a
900                  * ref_rev_parse_rules rule by interpolating "%s" at the
901                  * location of the "%.*s".
902                  */
903                 size_t total_len = 0;
904                 size_t offset = 0;
905
906                 /* the rule list is NULL terminated, count them first */
907                 for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++)
908                         /* -2 for strlen("%.*s") - strlen("%s"); +1 for NUL */
909                         total_len += strlen(ref_rev_parse_rules[nr_rules]) - 2 + 1;
910
911                 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
912
913                 offset = 0;
914                 for (i = 0; i < nr_rules; i++) {
915                         assert(offset < total_len);
916                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
917                         offset += snprintf(scanf_fmts[i], total_len - offset,
918                                            ref_rev_parse_rules[i], 2, "%s") + 1;
919                 }
920         }
921
922         /* bail out if there are no rules */
923         if (!nr_rules)
924                 return xstrdup(refname);
925
926         /* buffer for scanf result, at most refname must fit */
927         short_name = xstrdup(refname);
928
929         /* skip first rule, it will always match */
930         for (i = nr_rules - 1; i > 0 ; --i) {
931                 int j;
932                 int rules_to_fail = i;
933                 int short_name_len;
934
935                 if (1 != sscanf(refname, scanf_fmts[i], short_name))
936                         continue;
937
938                 short_name_len = strlen(short_name);
939
940                 /*
941                  * in strict mode, all (except the matched one) rules
942                  * must fail to resolve to a valid non-ambiguous ref
943                  */
944                 if (strict)
945                         rules_to_fail = nr_rules;
946
947                 /*
948                  * check if the short name resolves to a valid ref,
949                  * but use only rules prior to the matched one
950                  */
951                 for (j = 0; j < rules_to_fail; j++) {
952                         const char *rule = ref_rev_parse_rules[j];
953                         char refname[PATH_MAX];
954
955                         /* skip matched rule */
956                         if (i == j)
957                                 continue;
958
959                         /*
960                          * the short name is ambiguous, if it resolves
961                          * (with this previous rule) to a valid ref
962                          * read_ref() returns 0 on success
963                          */
964                         mksnpath(refname, sizeof(refname),
965                                  rule, short_name_len, short_name);
966                         if (ref_exists(refname))
967                                 break;
968                 }
969
970                 /*
971                  * short name is non-ambiguous if all previous rules
972                  * haven't resolved to a valid ref
973                  */
974                 if (j == rules_to_fail)
975                         return short_name;
976         }
977
978         free(short_name);
979         return xstrdup(refname);
980 }
981
982 static struct string_list *hide_refs;
983
984 int parse_hide_refs_config(const char *var, const char *value, const char *section)
985 {
986         if (!strcmp("transfer.hiderefs", var) ||
987             /* NEEDSWORK: use parse_config_key() once both are merged */
988             (starts_with(var, section) && var[strlen(section)] == '.' &&
989              !strcmp(var + strlen(section), ".hiderefs"))) {
990                 char *ref;
991                 int len;
992
993                 if (!value)
994                         return config_error_nonbool(var);
995                 ref = xstrdup(value);
996                 len = strlen(ref);
997                 while (len && ref[len - 1] == '/')
998                         ref[--len] = '\0';
999                 if (!hide_refs) {
1000                         hide_refs = xcalloc(1, sizeof(*hide_refs));
1001                         hide_refs->strdup_strings = 1;
1002                 }
1003                 string_list_append(hide_refs, ref);
1004         }
1005         return 0;
1006 }
1007
1008 int ref_is_hidden(const char *refname, const char *refname_full)
1009 {
1010         int i;
1011
1012         if (!hide_refs)
1013                 return 0;
1014         for (i = hide_refs->nr - 1; i >= 0; i--) {
1015                 const char *match = hide_refs->items[i].string;
1016                 const char *subject;
1017                 int neg = 0;
1018                 int len;
1019
1020                 if (*match == '!') {
1021                         neg = 1;
1022                         match++;
1023                 }
1024
1025                 if (*match == '^') {
1026                         subject = refname_full;
1027                         match++;
1028                 } else {
1029                         subject = refname;
1030                 }
1031
1032                 /* refname can be NULL when namespaces are used. */
1033                 if (!subject || !starts_with(subject, match))
1034                         continue;
1035                 len = strlen(match);
1036                 if (!subject[len] || subject[len] == '/')
1037                         return !neg;
1038         }
1039         return 0;
1040 }
1041
1042 const char *find_descendant_ref(const char *dirname,
1043                                 const struct string_list *extras,
1044                                 const struct string_list *skip)
1045 {
1046         int pos;
1047
1048         if (!extras)
1049                 return NULL;
1050
1051         /*
1052          * Look at the place where dirname would be inserted into
1053          * extras. If there is an entry at that position that starts
1054          * with dirname (remember, dirname includes the trailing
1055          * slash) and is not in skip, then we have a conflict.
1056          */
1057         for (pos = string_list_find_insert_index(extras, dirname, 0);
1058              pos < extras->nr; pos++) {
1059                 const char *extra_refname = extras->items[pos].string;
1060
1061                 if (!starts_with(extra_refname, dirname))
1062                         break;
1063
1064                 if (!skip || !string_list_has_string(skip, extra_refname))
1065                         return extra_refname;
1066         }
1067         return NULL;
1068 }
1069
1070 int rename_ref_available(const char *oldname, const char *newname)
1071 {
1072         struct string_list skip = STRING_LIST_INIT_NODUP;
1073         struct strbuf err = STRBUF_INIT;
1074         int ret;
1075
1076         string_list_insert(&skip, oldname);
1077         ret = !verify_refname_available(newname, NULL, &skip, &err);
1078         if (!ret)
1079                 error("%s", err.buf);
1080
1081         string_list_clear(&skip, 0);
1082         strbuf_release(&err);
1083         return ret;
1084 }