git-svn: hide find_parent_branch output in double quiet mode
[git] / refs.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "object.h"
4 #include "tag.h"
5 #include "dir.h"
6
7 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
8 #define REF_KNOWS_PEELED 04
9
10 struct ref_list {
11         struct ref_list *next;
12         unsigned char flag; /* ISSYMREF? ISPACKED? */
13         unsigned char sha1[20];
14         unsigned char peeled[20];
15         char name[FLEX_ARRAY];
16 };
17
18 static const char *parse_ref_line(char *line, unsigned char *sha1)
19 {
20         /*
21          * 42: the answer to everything.
22          *
23          * In this case, it happens to be the answer to
24          *  40 (length of sha1 hex representation)
25          *  +1 (space in between hex and name)
26          *  +1 (newline at the end of the line)
27          */
28         int len = strlen(line) - 42;
29
30         if (len <= 0)
31                 return NULL;
32         if (get_sha1_hex(line, sha1) < 0)
33                 return NULL;
34         if (!isspace(line[40]))
35                 return NULL;
36         line += 41;
37         if (isspace(*line))
38                 return NULL;
39         if (line[len] != '\n')
40                 return NULL;
41         line[len] = 0;
42
43         return line;
44 }
45
46 static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
47                                 int flag, struct ref_list *list,
48                                 struct ref_list **new_entry)
49 {
50         int len;
51         struct ref_list *entry;
52
53         /* Allocate it and add it in.. */
54         len = strlen(name) + 1;
55         entry = xmalloc(sizeof(struct ref_list) + len);
56         hashcpy(entry->sha1, sha1);
57         hashclr(entry->peeled);
58         memcpy(entry->name, name, len);
59         entry->flag = flag;
60         entry->next = list;
61         if (new_entry)
62                 *new_entry = entry;
63         return entry;
64 }
65
66 /* merge sort the ref list */
67 static struct ref_list *sort_ref_list(struct ref_list *list)
68 {
69         int psize, qsize, last_merge_count, cmp;
70         struct ref_list *p, *q, *l, *e;
71         struct ref_list *new_list = list;
72         int k = 1;
73         int merge_count = 0;
74
75         if (!list)
76                 return list;
77
78         do {
79                 last_merge_count = merge_count;
80                 merge_count = 0;
81
82                 psize = 0;
83
84                 p = new_list;
85                 q = new_list;
86                 new_list = NULL;
87                 l = NULL;
88
89                 while (p) {
90                         merge_count++;
91
92                         while (psize < k && q->next) {
93                                 q = q->next;
94                                 psize++;
95                         }
96                         qsize = k;
97
98                         while ((psize > 0) || (qsize > 0 && q)) {
99                                 if (qsize == 0 || !q) {
100                                         e = p;
101                                         p = p->next;
102                                         psize--;
103                                 } else if (psize == 0) {
104                                         e = q;
105                                         q = q->next;
106                                         qsize--;
107                                 } else {
108                                         cmp = strcmp(q->name, p->name);
109                                         if (cmp < 0) {
110                                                 e = q;
111                                                 q = q->next;
112                                                 qsize--;
113                                         } else if (cmp > 0) {
114                                                 e = p;
115                                                 p = p->next;
116                                                 psize--;
117                                         } else {
118                                                 if (hashcmp(q->sha1, p->sha1))
119                                                         die("Duplicated ref, and SHA1s don't match: %s",
120                                                             q->name);
121                                                 warning("Duplicated ref: %s", q->name);
122                                                 e = q;
123                                                 q = q->next;
124                                                 qsize--;
125                                                 free(e);
126                                                 e = p;
127                                                 p = p->next;
128                                                 psize--;
129                                         }
130                                 }
131
132                                 e->next = NULL;
133
134                                 if (l)
135                                         l->next = e;
136                                 if (!new_list)
137                                         new_list = e;
138                                 l = e;
139                         }
140
141                         p = q;
142                 };
143
144                 k = k * 2;
145         } while ((last_merge_count != merge_count) || (last_merge_count != 1));
146
147         return new_list;
148 }
149
150 /*
151  * Future: need to be in "struct repository"
152  * when doing a full libification.
153  */
154 static struct cached_refs {
155         char did_loose;
156         char did_packed;
157         struct ref_list *loose;
158         struct ref_list *packed;
159 } cached_refs;
160 static struct ref_list *current_ref;
161
162 static struct ref_list *extra_refs;
163
164 static void free_ref_list(struct ref_list *list)
165 {
166         struct ref_list *next;
167         for ( ; list; list = next) {
168                 next = list->next;
169                 free(list);
170         }
171 }
172
173 static void invalidate_cached_refs(void)
174 {
175         struct cached_refs *ca = &cached_refs;
176
177         if (ca->did_loose && ca->loose)
178                 free_ref_list(ca->loose);
179         if (ca->did_packed && ca->packed)
180                 free_ref_list(ca->packed);
181         ca->loose = ca->packed = NULL;
182         ca->did_loose = ca->did_packed = 0;
183 }
184
185 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
186 {
187         struct ref_list *list = NULL;
188         struct ref_list *last = NULL;
189         char refline[PATH_MAX];
190         int flag = REF_ISPACKED;
191
192         while (fgets(refline, sizeof(refline), f)) {
193                 unsigned char sha1[20];
194                 const char *name;
195                 static const char header[] = "# pack-refs with:";
196
197                 if (!strncmp(refline, header, sizeof(header)-1)) {
198                         const char *traits = refline + sizeof(header) - 1;
199                         if (strstr(traits, " peeled "))
200                                 flag |= REF_KNOWS_PEELED;
201                         /* perhaps other traits later as well */
202                         continue;
203                 }
204
205                 name = parse_ref_line(refline, sha1);
206                 if (name) {
207                         list = add_ref(name, sha1, flag, list, &last);
208                         continue;
209                 }
210                 if (last &&
211                     refline[0] == '^' &&
212                     strlen(refline) == 42 &&
213                     refline[41] == '\n' &&
214                     !get_sha1_hex(refline + 1, sha1))
215                         hashcpy(last->peeled, sha1);
216         }
217         cached_refs->packed = sort_ref_list(list);
218 }
219
220 void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
221 {
222         extra_refs = add_ref(name, sha1, flag, extra_refs, NULL);
223 }
224
225 void clear_extra_refs(void)
226 {
227         free_ref_list(extra_refs);
228         extra_refs = NULL;
229 }
230
231 static struct ref_list *get_packed_refs(void)
232 {
233         if (!cached_refs.did_packed) {
234                 FILE *f = fopen(git_path("packed-refs"), "r");
235                 cached_refs.packed = NULL;
236                 if (f) {
237                         read_packed_refs(f, &cached_refs);
238                         fclose(f);
239                 }
240                 cached_refs.did_packed = 1;
241         }
242         return cached_refs.packed;
243 }
244
245 static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
246 {
247         DIR *dir = opendir(git_path("%s", base));
248
249         if (dir) {
250                 struct dirent *de;
251                 int baselen = strlen(base);
252                 char *ref = xmalloc(baselen + 257);
253
254                 memcpy(ref, base, baselen);
255                 if (baselen && base[baselen-1] != '/')
256                         ref[baselen++] = '/';
257
258                 while ((de = readdir(dir)) != NULL) {
259                         unsigned char sha1[20];
260                         struct stat st;
261                         int flag;
262                         int namelen;
263
264                         if (de->d_name[0] == '.')
265                                 continue;
266                         namelen = strlen(de->d_name);
267                         if (namelen > 255)
268                                 continue;
269                         if (has_extension(de->d_name, ".lock"))
270                                 continue;
271                         memcpy(ref + baselen, de->d_name, namelen+1);
272                         if (stat(git_path("%s", ref), &st) < 0)
273                                 continue;
274                         if (S_ISDIR(st.st_mode)) {
275                                 list = get_ref_dir(ref, list);
276                                 continue;
277                         }
278                         if (!resolve_ref(ref, sha1, 1, &flag))
279                                 hashclr(sha1);
280                         list = add_ref(ref, sha1, flag, list, NULL);
281                 }
282                 free(ref);
283                 closedir(dir);
284         }
285         return sort_ref_list(list);
286 }
287
288 struct warn_if_dangling_data {
289         const char *refname;
290         const char *msg_fmt;
291 };
292
293 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
294                                    int flags, void *cb_data)
295 {
296         struct warn_if_dangling_data *d = cb_data;
297         const char *resolves_to;
298         unsigned char junk[20];
299
300         if (!(flags & REF_ISSYMREF))
301                 return 0;
302
303         resolves_to = resolve_ref(refname, junk, 0, NULL);
304         if (!resolves_to || strcmp(resolves_to, d->refname))
305                 return 0;
306
307         printf(d->msg_fmt, refname);
308         return 0;
309 }
310
311 void warn_dangling_symref(const char *msg_fmt, const char *refname)
312 {
313         struct warn_if_dangling_data data = { refname, msg_fmt };
314         for_each_rawref(warn_if_dangling_symref, &data);
315 }
316
317 static struct ref_list *get_loose_refs(void)
318 {
319         if (!cached_refs.did_loose) {
320                 cached_refs.loose = get_ref_dir("refs", NULL);
321                 cached_refs.did_loose = 1;
322         }
323         return cached_refs.loose;
324 }
325
326 /* We allow "recursive" symbolic refs. Only within reason, though */
327 #define MAXDEPTH 5
328 #define MAXREFLEN (1024)
329
330 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
331 {
332         FILE *f;
333         struct cached_refs refs;
334         struct ref_list *ref;
335         int retval;
336
337         strcpy(name + pathlen, "packed-refs");
338         f = fopen(name, "r");
339         if (!f)
340                 return -1;
341         read_packed_refs(f, &refs);
342         fclose(f);
343         ref = refs.packed;
344         retval = -1;
345         while (ref) {
346                 if (!strcmp(ref->name, refname)) {
347                         retval = 0;
348                         memcpy(result, ref->sha1, 20);
349                         break;
350                 }
351                 ref = ref->next;
352         }
353         free_ref_list(refs.packed);
354         return retval;
355 }
356
357 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
358 {
359         int fd, len = strlen(refname);
360         char buffer[128], *p;
361
362         if (recursion > MAXDEPTH || len > MAXREFLEN)
363                 return -1;
364         memcpy(name + pathlen, refname, len+1);
365         fd = open(name, O_RDONLY);
366         if (fd < 0)
367                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
368
369         len = read(fd, buffer, sizeof(buffer)-1);
370         close(fd);
371         if (len < 0)
372                 return -1;
373         while (len && isspace(buffer[len-1]))
374                 len--;
375         buffer[len] = 0;
376
377         /* Was it a detached head or an old-fashioned symlink? */
378         if (!get_sha1_hex(buffer, result))
379                 return 0;
380
381         /* Symref? */
382         if (strncmp(buffer, "ref:", 4))
383                 return -1;
384         p = buffer + 4;
385         while (isspace(*p))
386                 p++;
387
388         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
389 }
390
391 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
392 {
393         int len = strlen(path), retval;
394         char *gitdir;
395         const char *tmp;
396
397         while (len && path[len-1] == '/')
398                 len--;
399         if (!len)
400                 return -1;
401         gitdir = xmalloc(len + MAXREFLEN + 8);
402         memcpy(gitdir, path, len);
403         memcpy(gitdir + len, "/.git", 6);
404         len += 5;
405
406         tmp = read_gitfile_gently(gitdir);
407         if (tmp) {
408                 free(gitdir);
409                 len = strlen(tmp);
410                 gitdir = xmalloc(len + MAXREFLEN + 3);
411                 memcpy(gitdir, tmp, len);
412         }
413         gitdir[len] = '/';
414         gitdir[++len] = '\0';
415         retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
416         free(gitdir);
417         return retval;
418 }
419
420 /*
421  * If the "reading" argument is set, this function finds out what _object_
422  * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
423  * has to exist, and if it is symbolic, it has to point at an existing ref,
424  * because the "read" goes through the symref to the ref it points at.
425  *
426  * The access that is not "reading" may often be "writing", but does not
427  * have to; it can be merely checking _where it leads to_. If it is a
428  * prelude to "writing" to the ref, a write to a symref that points at
429  * yet-to-be-born ref will create the real ref pointed by the symref.
430  * reading=0 allows the caller to check where such a symref leads to.
431  */
432 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
433 {
434         int depth = MAXDEPTH;
435         ssize_t len;
436         char buffer[256];
437         static char ref_buffer[256];
438
439         if (flag)
440                 *flag = 0;
441
442         for (;;) {
443                 char path[PATH_MAX];
444                 struct stat st;
445                 char *buf;
446                 int fd;
447
448                 if (--depth < 0)
449                         return NULL;
450
451                 git_snpath(path, sizeof(path), "%s", ref);
452                 /* Special case: non-existing file. */
453                 if (lstat(path, &st) < 0) {
454                         struct ref_list *list = get_packed_refs();
455                         while (list) {
456                                 if (!strcmp(ref, list->name)) {
457                                         hashcpy(sha1, list->sha1);
458                                         if (flag)
459                                                 *flag |= REF_ISPACKED;
460                                         return ref;
461                                 }
462                                 list = list->next;
463                         }
464                         if (reading || errno != ENOENT)
465                                 return NULL;
466                         hashclr(sha1);
467                         return ref;
468                 }
469
470                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
471                 if (S_ISLNK(st.st_mode)) {
472                         len = readlink(path, buffer, sizeof(buffer)-1);
473                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
474                                 buffer[len] = 0;
475                                 strcpy(ref_buffer, buffer);
476                                 ref = ref_buffer;
477                                 if (flag)
478                                         *flag |= REF_ISSYMREF;
479                                 continue;
480                         }
481                 }
482
483                 /* Is it a directory? */
484                 if (S_ISDIR(st.st_mode)) {
485                         errno = EISDIR;
486                         return NULL;
487                 }
488
489                 /*
490                  * Anything else, just open it and try to use it as
491                  * a ref
492                  */
493                 fd = open(path, O_RDONLY);
494                 if (fd < 0)
495                         return NULL;
496                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
497                 close(fd);
498
499                 /*
500                  * Is it a symbolic ref?
501                  */
502                 if (len < 4 || memcmp("ref:", buffer, 4))
503                         break;
504                 buf = buffer + 4;
505                 len -= 4;
506                 while (len && isspace(*buf))
507                         buf++, len--;
508                 while (len && isspace(buf[len-1]))
509                         len--;
510                 buf[len] = 0;
511                 memcpy(ref_buffer, buf, len + 1);
512                 ref = ref_buffer;
513                 if (flag)
514                         *flag |= REF_ISSYMREF;
515         }
516         if (len < 40 || get_sha1_hex(buffer, sha1))
517                 return NULL;
518         return ref;
519 }
520
521 int read_ref(const char *ref, unsigned char *sha1)
522 {
523         if (resolve_ref(ref, sha1, 1, NULL))
524                 return 0;
525         return -1;
526 }
527
528 #define DO_FOR_EACH_INCLUDE_BROKEN 01
529 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
530                       int flags, void *cb_data, struct ref_list *entry)
531 {
532         if (strncmp(base, entry->name, trim))
533                 return 0;
534         /* Is this a "negative ref" that represents a deleted ref? */
535         if (is_null_sha1(entry->sha1))
536                 return 0;
537         if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
538                 if (!has_sha1_file(entry->sha1)) {
539                         error("%s does not point to a valid object!", entry->name);
540                         return 0;
541                 }
542         }
543         current_ref = entry;
544         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
545 }
546
547 int peel_ref(const char *ref, unsigned char *sha1)
548 {
549         int flag;
550         unsigned char base[20];
551         struct object *o;
552
553         if (current_ref && (current_ref->name == ref
554                 || !strcmp(current_ref->name, ref))) {
555                 if (current_ref->flag & REF_KNOWS_PEELED) {
556                         hashcpy(sha1, current_ref->peeled);
557                         return 0;
558                 }
559                 hashcpy(base, current_ref->sha1);
560                 goto fallback;
561         }
562
563         if (!resolve_ref(ref, base, 1, &flag))
564                 return -1;
565
566         if ((flag & REF_ISPACKED)) {
567                 struct ref_list *list = get_packed_refs();
568
569                 while (list) {
570                         if (!strcmp(list->name, ref)) {
571                                 if (list->flag & REF_KNOWS_PEELED) {
572                                         hashcpy(sha1, list->peeled);
573                                         return 0;
574                                 }
575                                 /* older pack-refs did not leave peeled ones */
576                                 break;
577                         }
578                         list = list->next;
579                 }
580         }
581
582 fallback:
583         o = parse_object(base);
584         if (o && o->type == OBJ_TAG) {
585                 o = deref_tag(o, ref, 0);
586                 if (o) {
587                         hashcpy(sha1, o->sha1);
588                         return 0;
589                 }
590         }
591         return -1;
592 }
593
594 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
595                            int flags, void *cb_data)
596 {
597         int retval = 0;
598         struct ref_list *packed = get_packed_refs();
599         struct ref_list *loose = get_loose_refs();
600
601         struct ref_list *extra;
602
603         for (extra = extra_refs; extra; extra = extra->next)
604                 retval = do_one_ref(base, fn, trim, flags, cb_data, extra);
605
606         while (packed && loose) {
607                 struct ref_list *entry;
608                 int cmp = strcmp(packed->name, loose->name);
609                 if (!cmp) {
610                         packed = packed->next;
611                         continue;
612                 }
613                 if (cmp > 0) {
614                         entry = loose;
615                         loose = loose->next;
616                 } else {
617                         entry = packed;
618                         packed = packed->next;
619                 }
620                 retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
621                 if (retval)
622                         goto end_each;
623         }
624
625         for (packed = packed ? packed : loose; packed; packed = packed->next) {
626                 retval = do_one_ref(base, fn, trim, flags, cb_data, packed);
627                 if (retval)
628                         goto end_each;
629         }
630
631 end_each:
632         current_ref = NULL;
633         return retval;
634 }
635
636 int head_ref(each_ref_fn fn, void *cb_data)
637 {
638         unsigned char sha1[20];
639         int flag;
640
641         if (resolve_ref("HEAD", sha1, 1, &flag))
642                 return fn("HEAD", sha1, flag, cb_data);
643         return 0;
644 }
645
646 int for_each_ref(each_ref_fn fn, void *cb_data)
647 {
648         return do_for_each_ref("refs/", fn, 0, 0, cb_data);
649 }
650
651 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
652 {
653         return do_for_each_ref(prefix, fn, strlen(prefix), 0, cb_data);
654 }
655
656 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
657 {
658         return for_each_ref_in("refs/tags/", fn, cb_data);
659 }
660
661 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
662 {
663         return for_each_ref_in("refs/heads/", fn, cb_data);
664 }
665
666 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
667 {
668         return for_each_ref_in("refs/remotes/", fn, cb_data);
669 }
670
671 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
672 {
673         return do_for_each_ref("refs/replace/", fn, 13, 0, cb_data);
674 }
675
676 int for_each_rawref(each_ref_fn fn, void *cb_data)
677 {
678         return do_for_each_ref("refs/", fn, 0,
679                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
680 }
681
682 /*
683  * Make sure "ref" is something reasonable to have under ".git/refs/";
684  * We do not like it if:
685  *
686  * - any path component of it begins with ".", or
687  * - it has double dots "..", or
688  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
689  * - it ends with a "/".
690  * - it ends with ".lock"
691  * - it contains a "\" (backslash)
692  */
693
694 static inline int bad_ref_char(int ch)
695 {
696         if (((unsigned) ch) <= ' ' ||
697             ch == '~' || ch == '^' || ch == ':' || ch == '\\')
698                 return 1;
699         /* 2.13 Pattern Matching Notation */
700         if (ch == '?' || ch == '[') /* Unsupported */
701                 return 1;
702         if (ch == '*') /* Supported at the end */
703                 return 2;
704         return 0;
705 }
706
707 int check_ref_format(const char *ref)
708 {
709         int ch, level, bad_type, last;
710         int ret = CHECK_REF_FORMAT_OK;
711         const char *cp = ref;
712
713         level = 0;
714         while (1) {
715                 while ((ch = *cp++) == '/')
716                         ; /* tolerate duplicated slashes */
717                 if (!ch)
718                         /* should not end with slashes */
719                         return CHECK_REF_FORMAT_ERROR;
720
721                 /* we are at the beginning of the path component */
722                 if (ch == '.')
723                         return CHECK_REF_FORMAT_ERROR;
724                 bad_type = bad_ref_char(ch);
725                 if (bad_type) {
726                         if (bad_type == 2 && (!*cp || *cp == '/') &&
727                             ret == CHECK_REF_FORMAT_OK)
728                                 ret = CHECK_REF_FORMAT_WILDCARD;
729                         else
730                                 return CHECK_REF_FORMAT_ERROR;
731                 }
732
733                 last = ch;
734                 /* scan the rest of the path component */
735                 while ((ch = *cp++) != 0) {
736                         bad_type = bad_ref_char(ch);
737                         if (bad_type)
738                                 return CHECK_REF_FORMAT_ERROR;
739                         if (ch == '/')
740                                 break;
741                         if (last == '.' && ch == '.')
742                                 return CHECK_REF_FORMAT_ERROR;
743                         if (last == '@' && ch == '{')
744                                 return CHECK_REF_FORMAT_ERROR;
745                         last = ch;
746                 }
747                 level++;
748                 if (!ch) {
749                         if (ref <= cp - 2 && cp[-2] == '.')
750                                 return CHECK_REF_FORMAT_ERROR;
751                         if (level < 2)
752                                 return CHECK_REF_FORMAT_ONELEVEL;
753                         if (has_extension(ref, ".lock"))
754                                 return CHECK_REF_FORMAT_ERROR;
755                         return ret;
756                 }
757         }
758 }
759
760 const char *prettify_refname(const char *name)
761 {
762         return name + (
763                 !prefixcmp(name, "refs/heads/") ? 11 :
764                 !prefixcmp(name, "refs/tags/") ? 10 :
765                 !prefixcmp(name, "refs/remotes/") ? 13 :
766                 0);
767 }
768
769 const char *ref_rev_parse_rules[] = {
770         "%.*s",
771         "refs/%.*s",
772         "refs/tags/%.*s",
773         "refs/heads/%.*s",
774         "refs/remotes/%.*s",
775         "refs/remotes/%.*s/HEAD",
776         NULL
777 };
778
779 const char *ref_fetch_rules[] = {
780         "%.*s",
781         "refs/%.*s",
782         "refs/heads/%.*s",
783         NULL
784 };
785
786 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
787 {
788         const char **p;
789         const int abbrev_name_len = strlen(abbrev_name);
790
791         for (p = rules; *p; p++) {
792                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
793                         return 1;
794                 }
795         }
796
797         return 0;
798 }
799
800 static struct ref_lock *verify_lock(struct ref_lock *lock,
801         const unsigned char *old_sha1, int mustexist)
802 {
803         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
804                 error("Can't verify ref %s", lock->ref_name);
805                 unlock_ref(lock);
806                 return NULL;
807         }
808         if (hashcmp(lock->old_sha1, old_sha1)) {
809                 error("Ref %s is at %s but expected %s", lock->ref_name,
810                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
811                 unlock_ref(lock);
812                 return NULL;
813         }
814         return lock;
815 }
816
817 static int remove_empty_directories(const char *file)
818 {
819         /* we want to create a file but there is a directory there;
820          * if that is an empty directory (or a directory that contains
821          * only empty directories), remove them.
822          */
823         struct strbuf path;
824         int result;
825
826         strbuf_init(&path, 20);
827         strbuf_addstr(&path, file);
828
829         result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
830
831         strbuf_release(&path);
832
833         return result;
834 }
835
836 static int is_refname_available(const char *ref, const char *oldref,
837                                 struct ref_list *list, int quiet)
838 {
839         int namlen = strlen(ref); /* e.g. 'foo/bar' */
840         while (list) {
841                 /* list->name could be 'foo' or 'foo/bar/baz' */
842                 if (!oldref || strcmp(oldref, list->name)) {
843                         int len = strlen(list->name);
844                         int cmplen = (namlen < len) ? namlen : len;
845                         const char *lead = (namlen < len) ? list->name : ref;
846                         if (!strncmp(ref, list->name, cmplen) &&
847                             lead[cmplen] == '/') {
848                                 if (!quiet)
849                                         error("'%s' exists; cannot create '%s'",
850                                               list->name, ref);
851                                 return 0;
852                         }
853                 }
854                 list = list->next;
855         }
856         return 1;
857 }
858
859 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
860 {
861         char *ref_file;
862         const char *orig_ref = ref;
863         struct ref_lock *lock;
864         int last_errno = 0;
865         int type, lflags;
866         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
867         int missing = 0;
868
869         lock = xcalloc(1, sizeof(struct ref_lock));
870         lock->lock_fd = -1;
871
872         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
873         if (!ref && errno == EISDIR) {
874                 /* we are trying to lock foo but we used to
875                  * have foo/bar which now does not exist;
876                  * it is normal for the empty directory 'foo'
877                  * to remain.
878                  */
879                 ref_file = git_path("%s", orig_ref);
880                 if (remove_empty_directories(ref_file)) {
881                         last_errno = errno;
882                         error("there are still refs under '%s'", orig_ref);
883                         goto error_return;
884                 }
885                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
886         }
887         if (type_p)
888             *type_p = type;
889         if (!ref) {
890                 last_errno = errno;
891                 error("unable to resolve reference %s: %s",
892                         orig_ref, strerror(errno));
893                 goto error_return;
894         }
895         missing = is_null_sha1(lock->old_sha1);
896         /* When the ref did not exist and we are creating it,
897          * make sure there is no existing ref that is packed
898          * whose name begins with our refname, nor a ref whose
899          * name is a proper prefix of our refname.
900          */
901         if (missing &&
902              !is_refname_available(ref, NULL, get_packed_refs(), 0)) {
903                 last_errno = ENOTDIR;
904                 goto error_return;
905         }
906
907         lock->lk = xcalloc(1, sizeof(struct lock_file));
908
909         lflags = LOCK_DIE_ON_ERROR;
910         if (flags & REF_NODEREF) {
911                 ref = orig_ref;
912                 lflags |= LOCK_NODEREF;
913         }
914         lock->ref_name = xstrdup(ref);
915         lock->orig_ref_name = xstrdup(orig_ref);
916         ref_file = git_path("%s", ref);
917         if (missing)
918                 lock->force_write = 1;
919         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
920                 lock->force_write = 1;
921
922         if (safe_create_leading_directories(ref_file)) {
923                 last_errno = errno;
924                 error("unable to create directory for %s", ref_file);
925                 goto error_return;
926         }
927
928         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
929         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
930
931  error_return:
932         unlock_ref(lock);
933         errno = last_errno;
934         return NULL;
935 }
936
937 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
938 {
939         char refpath[PATH_MAX];
940         if (check_ref_format(ref))
941                 return NULL;
942         strcpy(refpath, mkpath("refs/%s", ref));
943         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
944 }
945
946 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
947 {
948         switch (check_ref_format(ref)) {
949         default:
950                 return NULL;
951         case 0:
952         case CHECK_REF_FORMAT_ONELEVEL:
953                 return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
954         }
955 }
956
957 static struct lock_file packlock;
958
959 static int repack_without_ref(const char *refname)
960 {
961         struct ref_list *list, *packed_ref_list;
962         int fd;
963         int found = 0;
964
965         packed_ref_list = get_packed_refs();
966         for (list = packed_ref_list; list; list = list->next) {
967                 if (!strcmp(refname, list->name)) {
968                         found = 1;
969                         break;
970                 }
971         }
972         if (!found)
973                 return 0;
974         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
975         if (fd < 0) {
976                 unable_to_lock_error(git_path("packed-refs"), errno);
977                 return error("cannot delete '%s' from packed refs", refname);
978         }
979
980         for (list = packed_ref_list; list; list = list->next) {
981                 char line[PATH_MAX + 100];
982                 int len;
983
984                 if (!strcmp(refname, list->name))
985                         continue;
986                 len = snprintf(line, sizeof(line), "%s %s\n",
987                                sha1_to_hex(list->sha1), list->name);
988                 /* this should not happen but just being defensive */
989                 if (len > sizeof(line))
990                         die("too long a refname '%s'", list->name);
991                 write_or_die(fd, line, len);
992         }
993         return commit_lock_file(&packlock);
994 }
995
996 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
997 {
998         struct ref_lock *lock;
999         int err, i = 0, ret = 0, flag = 0;
1000
1001         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1002         if (!lock)
1003                 return 1;
1004         if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1005                 /* loose */
1006                 const char *path;
1007
1008                 if (!(delopt & REF_NODEREF)) {
1009                         i = strlen(lock->lk->filename) - 5; /* .lock */
1010                         lock->lk->filename[i] = 0;
1011                         path = lock->lk->filename;
1012                 } else {
1013                         path = git_path("%s", refname);
1014                 }
1015                 err = unlink_or_warn(path);
1016                 if (err && errno != ENOENT)
1017                         ret = 1;
1018
1019                 if (!(delopt & REF_NODEREF))
1020                         lock->lk->filename[i] = '.';
1021         }
1022         /* removing the loose one could have resurrected an earlier
1023          * packed one.  Also, if it was not loose we need to repack
1024          * without it.
1025          */
1026         ret |= repack_without_ref(refname);
1027
1028         unlink_or_warn(git_path("logs/%s", lock->ref_name));
1029         invalidate_cached_refs();
1030         unlock_ref(lock);
1031         return ret;
1032 }
1033
1034 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1035 {
1036         static const char renamed_ref[] = "RENAMED-REF";
1037         unsigned char sha1[20], orig_sha1[20];
1038         int flag = 0, logmoved = 0;
1039         struct ref_lock *lock;
1040         struct stat loginfo;
1041         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1042         const char *symref = NULL;
1043
1044         if (log && S_ISLNK(loginfo.st_mode))
1045                 return error("reflog for %s is a symlink", oldref);
1046
1047         symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1048         if (flag & REF_ISSYMREF)
1049                 return error("refname %s is a symbolic ref, renaming it is not supported",
1050                         oldref);
1051         if (!symref)
1052                 return error("refname %s not found", oldref);
1053
1054         if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
1055                 return 1;
1056
1057         if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
1058                 return 1;
1059
1060         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
1061         if (!lock)
1062                 return error("unable to lock %s", renamed_ref);
1063         lock->force_write = 1;
1064         if (write_ref_sha1(lock, orig_sha1, logmsg))
1065                 return error("unable to save current sha1 in %s", renamed_ref);
1066
1067         if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
1068                 return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
1069                         oldref, strerror(errno));
1070
1071         if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1072                 error("unable to delete old %s", oldref);
1073                 goto rollback;
1074         }
1075
1076         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1077                 if (errno==EISDIR) {
1078                         if (remove_empty_directories(git_path("%s", newref))) {
1079                                 error("Directory not empty: %s", newref);
1080                                 goto rollback;
1081                         }
1082                 } else {
1083                         error("unable to delete existing %s", newref);
1084                         goto rollback;
1085                 }
1086         }
1087
1088         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1089                 error("unable to create directory for %s", newref);
1090                 goto rollback;
1091         }
1092
1093  retry:
1094         if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
1095                 if (errno==EISDIR || errno==ENOTDIR) {
1096                         /*
1097                          * rename(a, b) when b is an existing
1098                          * directory ought to result in ISDIR, but
1099                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1100                          */
1101                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1102                                 error("Directory not empty: logs/%s", newref);
1103                                 goto rollback;
1104                         }
1105                         goto retry;
1106                 } else {
1107                         error("unable to move logfile tmp-renamed-log to logs/%s: %s",
1108                                 newref, strerror(errno));
1109                         goto rollback;
1110                 }
1111         }
1112         logmoved = log;
1113
1114         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1115         if (!lock) {
1116                 error("unable to lock %s for update", newref);
1117                 goto rollback;
1118         }
1119         lock->force_write = 1;
1120         hashcpy(lock->old_sha1, orig_sha1);
1121         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1122                 error("unable to write current sha1 into %s", newref);
1123                 goto rollback;
1124         }
1125
1126         return 0;
1127
1128  rollback:
1129         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1130         if (!lock) {
1131                 error("unable to lock %s for rollback", oldref);
1132                 goto rollbacklog;
1133         }
1134
1135         lock->force_write = 1;
1136         flag = log_all_ref_updates;
1137         log_all_ref_updates = 0;
1138         if (write_ref_sha1(lock, orig_sha1, NULL))
1139                 error("unable to write current sha1 into %s", oldref);
1140         log_all_ref_updates = flag;
1141
1142  rollbacklog:
1143         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1144                 error("unable to restore logfile %s from %s: %s",
1145                         oldref, newref, strerror(errno));
1146         if (!logmoved && log &&
1147             rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
1148                 error("unable to restore logfile %s from tmp-renamed-log: %s",
1149                         oldref, strerror(errno));
1150
1151         return 1;
1152 }
1153
1154 int close_ref(struct ref_lock *lock)
1155 {
1156         if (close_lock_file(lock->lk))
1157                 return -1;
1158         lock->lock_fd = -1;
1159         return 0;
1160 }
1161
1162 int commit_ref(struct ref_lock *lock)
1163 {
1164         if (commit_lock_file(lock->lk))
1165                 return -1;
1166         lock->lock_fd = -1;
1167         return 0;
1168 }
1169
1170 void unlock_ref(struct ref_lock *lock)
1171 {
1172         /* Do not free lock->lk -- atexit() still looks at them */
1173         if (lock->lk)
1174                 rollback_lock_file(lock->lk);
1175         free(lock->ref_name);
1176         free(lock->orig_ref_name);
1177         free(lock);
1178 }
1179
1180 /*
1181  * copy the reflog message msg to buf, which has been allocated sufficiently
1182  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1183  * because reflog file is one line per entry.
1184  */
1185 static int copy_msg(char *buf, const char *msg)
1186 {
1187         char *cp = buf;
1188         char c;
1189         int wasspace = 1;
1190
1191         *cp++ = '\t';
1192         while ((c = *msg++)) {
1193                 if (wasspace && isspace(c))
1194                         continue;
1195                 wasspace = isspace(c);
1196                 if (wasspace)
1197                         c = ' ';
1198                 *cp++ = c;
1199         }
1200         while (buf < cp && isspace(cp[-1]))
1201                 cp--;
1202         *cp++ = '\n';
1203         return cp - buf;
1204 }
1205
1206 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1207                          const unsigned char *new_sha1, const char *msg)
1208 {
1209         int logfd, written, oflags = O_APPEND | O_WRONLY;
1210         unsigned maxlen, len;
1211         int msglen;
1212         char log_file[PATH_MAX];
1213         char *logrec;
1214         const char *committer;
1215
1216         if (log_all_ref_updates < 0)
1217                 log_all_ref_updates = !is_bare_repository();
1218
1219         git_snpath(log_file, sizeof(log_file), "logs/%s", ref_name);
1220
1221         if (log_all_ref_updates &&
1222             (!prefixcmp(ref_name, "refs/heads/") ||
1223              !prefixcmp(ref_name, "refs/remotes/") ||
1224              !strcmp(ref_name, "HEAD"))) {
1225                 if (safe_create_leading_directories(log_file) < 0)
1226                         return error("unable to create directory for %s",
1227                                      log_file);
1228                 oflags |= O_CREAT;
1229         }
1230
1231         logfd = open(log_file, oflags, 0666);
1232         if (logfd < 0) {
1233                 if (!(oflags & O_CREAT) && errno == ENOENT)
1234                         return 0;
1235
1236                 if ((oflags & O_CREAT) && errno == EISDIR) {
1237                         if (remove_empty_directories(log_file)) {
1238                                 return error("There are still logs under '%s'",
1239                                              log_file);
1240                         }
1241                         logfd = open(log_file, oflags, 0666);
1242                 }
1243
1244                 if (logfd < 0)
1245                         return error("Unable to append to %s: %s",
1246                                      log_file, strerror(errno));
1247         }
1248
1249         adjust_shared_perm(log_file);
1250
1251         msglen = msg ? strlen(msg) : 0;
1252         committer = git_committer_info(0);
1253         maxlen = strlen(committer) + msglen + 100;
1254         logrec = xmalloc(maxlen);
1255         len = sprintf(logrec, "%s %s %s\n",
1256                       sha1_to_hex(old_sha1),
1257                       sha1_to_hex(new_sha1),
1258                       committer);
1259         if (msglen)
1260                 len += copy_msg(logrec + len - 1, msg) - 1;
1261         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1262         free(logrec);
1263         if (close(logfd) != 0 || written != len)
1264                 return error("Unable to append to %s", log_file);
1265         return 0;
1266 }
1267
1268 static int is_branch(const char *refname)
1269 {
1270         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1271 }
1272
1273 int write_ref_sha1(struct ref_lock *lock,
1274         const unsigned char *sha1, const char *logmsg)
1275 {
1276         static char term = '\n';
1277         struct object *o;
1278
1279         if (!lock)
1280                 return -1;
1281         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1282                 unlock_ref(lock);
1283                 return 0;
1284         }
1285         o = parse_object(sha1);
1286         if (!o) {
1287                 error("Trying to write ref %s with nonexistant object %s",
1288                         lock->ref_name, sha1_to_hex(sha1));
1289                 unlock_ref(lock);
1290                 return -1;
1291         }
1292         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1293                 error("Trying to write non-commit object %s to branch %s",
1294                         sha1_to_hex(sha1), lock->ref_name);
1295                 unlock_ref(lock);
1296                 return -1;
1297         }
1298         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1299             write_in_full(lock->lock_fd, &term, 1) != 1
1300                 || close_ref(lock) < 0) {
1301                 error("Couldn't write %s", lock->lk->filename);
1302                 unlock_ref(lock);
1303                 return -1;
1304         }
1305         invalidate_cached_refs();
1306         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1307             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1308              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1309                 unlock_ref(lock);
1310                 return -1;
1311         }
1312         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1313                 /*
1314                  * Special hack: If a branch is updated directly and HEAD
1315                  * points to it (may happen on the remote side of a push
1316                  * for example) then logically the HEAD reflog should be
1317                  * updated too.
1318                  * A generic solution implies reverse symref information,
1319                  * but finding all symrefs pointing to the given branch
1320                  * would be rather costly for this rare event (the direct
1321                  * update of a branch) to be worth it.  So let's cheat and
1322                  * check with HEAD only which should cover 99% of all usage
1323                  * scenarios (even 100% of the default ones).
1324                  */
1325                 unsigned char head_sha1[20];
1326                 int head_flag;
1327                 const char *head_ref;
1328                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1329                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1330                     !strcmp(head_ref, lock->ref_name))
1331                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1332         }
1333         if (commit_ref(lock)) {
1334                 error("Couldn't set %s", lock->ref_name);
1335                 unlock_ref(lock);
1336                 return -1;
1337         }
1338         unlock_ref(lock);
1339         return 0;
1340 }
1341
1342 int create_symref(const char *ref_target, const char *refs_heads_master,
1343                   const char *logmsg)
1344 {
1345         const char *lockpath;
1346         char ref[1000];
1347         int fd, len, written;
1348         char *git_HEAD = git_pathdup("%s", ref_target);
1349         unsigned char old_sha1[20], new_sha1[20];
1350
1351         if (logmsg && read_ref(ref_target, old_sha1))
1352                 hashclr(old_sha1);
1353
1354         if (safe_create_leading_directories(git_HEAD) < 0)
1355                 return error("unable to create directory for %s", git_HEAD);
1356
1357 #ifndef NO_SYMLINK_HEAD
1358         if (prefer_symlink_refs) {
1359                 unlink(git_HEAD);
1360                 if (!symlink(refs_heads_master, git_HEAD))
1361                         goto done;
1362                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1363         }
1364 #endif
1365
1366         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1367         if (sizeof(ref) <= len) {
1368                 error("refname too long: %s", refs_heads_master);
1369                 goto error_free_return;
1370         }
1371         lockpath = mkpath("%s.lock", git_HEAD);
1372         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1373         if (fd < 0) {
1374                 error("Unable to open %s for writing", lockpath);
1375                 goto error_free_return;
1376         }
1377         written = write_in_full(fd, ref, len);
1378         if (close(fd) != 0 || written != len) {
1379                 error("Unable to write to %s", lockpath);
1380                 goto error_unlink_return;
1381         }
1382         if (rename(lockpath, git_HEAD) < 0) {
1383                 error("Unable to create %s", git_HEAD);
1384                 goto error_unlink_return;
1385         }
1386         if (adjust_shared_perm(git_HEAD)) {
1387                 error("Unable to fix permissions on %s", lockpath);
1388         error_unlink_return:
1389                 unlink_or_warn(lockpath);
1390         error_free_return:
1391                 free(git_HEAD);
1392                 return -1;
1393         }
1394
1395 #ifndef NO_SYMLINK_HEAD
1396         done:
1397 #endif
1398         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1399                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1400
1401         free(git_HEAD);
1402         return 0;
1403 }
1404
1405 static char *ref_msg(const char *line, const char *endp)
1406 {
1407         const char *ep;
1408         line += 82;
1409         ep = memchr(line, '\n', endp - line);
1410         if (!ep)
1411                 ep = endp;
1412         return xmemdupz(line, ep - line);
1413 }
1414
1415 int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned char *sha1, char **msg, unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
1416 {
1417         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1418         char *tz_c;
1419         int logfd, tz, reccnt = 0;
1420         struct stat st;
1421         unsigned long date;
1422         unsigned char logged_sha1[20];
1423         void *log_mapped;
1424         size_t mapsz;
1425
1426         logfile = git_path("logs/%s", ref);
1427         logfd = open(logfile, O_RDONLY, 0);
1428         if (logfd < 0)
1429                 die_errno("Unable to read log '%s'", logfile);
1430         fstat(logfd, &st);
1431         if (!st.st_size)
1432                 die("Log %s is empty.", logfile);
1433         mapsz = xsize_t(st.st_size);
1434         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1435         logdata = log_mapped;
1436         close(logfd);
1437
1438         lastrec = NULL;
1439         rec = logend = logdata + st.st_size;
1440         while (logdata < rec) {
1441                 reccnt++;
1442                 if (logdata < rec && *(rec-1) == '\n')
1443                         rec--;
1444                 lastgt = NULL;
1445                 while (logdata < rec && *(rec-1) != '\n') {
1446                         rec--;
1447                         if (*rec == '>')
1448                                 lastgt = rec;
1449                 }
1450                 if (!lastgt)
1451                         die("Log %s is corrupt.", logfile);
1452                 date = strtoul(lastgt + 1, &tz_c, 10);
1453                 if (date <= at_time || cnt == 0) {
1454                         tz = strtoul(tz_c, NULL, 10);
1455                         if (msg)
1456                                 *msg = ref_msg(rec, logend);
1457                         if (cutoff_time)
1458                                 *cutoff_time = date;
1459                         if (cutoff_tz)
1460                                 *cutoff_tz = tz;
1461                         if (cutoff_cnt)
1462                                 *cutoff_cnt = reccnt - 1;
1463                         if (lastrec) {
1464                                 if (get_sha1_hex(lastrec, logged_sha1))
1465                                         die("Log %s is corrupt.", logfile);
1466                                 if (get_sha1_hex(rec + 41, sha1))
1467                                         die("Log %s is corrupt.", logfile);
1468                                 if (hashcmp(logged_sha1, sha1)) {
1469                                         warning("Log %s has gap after %s.",
1470                                                 logfile, show_date(date, tz, DATE_RFC2822));
1471                                 }
1472                         }
1473                         else if (date == at_time) {
1474                                 if (get_sha1_hex(rec + 41, sha1))
1475                                         die("Log %s is corrupt.", logfile);
1476                         }
1477                         else {
1478                                 if (get_sha1_hex(rec + 41, logged_sha1))
1479                                         die("Log %s is corrupt.", logfile);
1480                                 if (hashcmp(logged_sha1, sha1)) {
1481                                         warning("Log %s unexpectedly ended on %s.",
1482                                                 logfile, show_date(date, tz, DATE_RFC2822));
1483                                 }
1484                         }
1485                         munmap(log_mapped, mapsz);
1486                         return 0;
1487                 }
1488                 lastrec = rec;
1489                 if (cnt > 0)
1490                         cnt--;
1491         }
1492
1493         rec = logdata;
1494         while (rec < logend && *rec != '>' && *rec != '\n')
1495                 rec++;
1496         if (rec == logend || *rec == '\n')
1497                 die("Log %s is corrupt.", logfile);
1498         date = strtoul(rec + 1, &tz_c, 10);
1499         tz = strtoul(tz_c, NULL, 10);
1500         if (get_sha1_hex(logdata, sha1))
1501                 die("Log %s is corrupt.", logfile);
1502         if (is_null_sha1(sha1)) {
1503                 if (get_sha1_hex(logdata + 41, sha1))
1504                         die("Log %s is corrupt.", logfile);
1505         }
1506         if (msg)
1507                 *msg = ref_msg(logdata, logend);
1508         munmap(log_mapped, mapsz);
1509
1510         if (cutoff_time)
1511                 *cutoff_time = date;
1512         if (cutoff_tz)
1513                 *cutoff_tz = tz;
1514         if (cutoff_cnt)
1515                 *cutoff_cnt = reccnt;
1516         return 1;
1517 }
1518
1519 int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1520 {
1521         const char *logfile;
1522         FILE *logfp;
1523         char buf[1024];
1524         int ret = 0;
1525
1526         logfile = git_path("logs/%s", ref);
1527         logfp = fopen(logfile, "r");
1528         if (!logfp)
1529                 return -1;
1530
1531         if (ofs) {
1532                 struct stat statbuf;
1533                 if (fstat(fileno(logfp), &statbuf) ||
1534                     statbuf.st_size < ofs ||
1535                     fseek(logfp, -ofs, SEEK_END) ||
1536                     fgets(buf, sizeof(buf), logfp)) {
1537                         fclose(logfp);
1538                         return -1;
1539                 }
1540         }
1541
1542         while (fgets(buf, sizeof(buf), logfp)) {
1543                 unsigned char osha1[20], nsha1[20];
1544                 char *email_end, *message;
1545                 unsigned long timestamp;
1546                 int len, tz;
1547
1548                 /* old SP new SP name <email> SP time TAB msg LF */
1549                 len = strlen(buf);
1550                 if (len < 83 || buf[len-1] != '\n' ||
1551                     get_sha1_hex(buf, osha1) || buf[40] != ' ' ||
1552                     get_sha1_hex(buf + 41, nsha1) || buf[81] != ' ' ||
1553                     !(email_end = strchr(buf + 82, '>')) ||
1554                     email_end[1] != ' ' ||
1555                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1556                     !message || message[0] != ' ' ||
1557                     (message[1] != '+' && message[1] != '-') ||
1558                     !isdigit(message[2]) || !isdigit(message[3]) ||
1559                     !isdigit(message[4]) || !isdigit(message[5]))
1560                         continue; /* corrupt? */
1561                 email_end[1] = '\0';
1562                 tz = strtol(message + 1, NULL, 10);
1563                 if (message[6] != '\t')
1564                         message += 6;
1565                 else
1566                         message += 7;
1567                 ret = fn(osha1, nsha1, buf+82, timestamp, tz, message, cb_data);
1568                 if (ret)
1569                         break;
1570         }
1571         fclose(logfp);
1572         return ret;
1573 }
1574
1575 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1576 {
1577         return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1578 }
1579
1580 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1581 {
1582         DIR *dir = opendir(git_path("logs/%s", base));
1583         int retval = 0;
1584
1585         if (dir) {
1586                 struct dirent *de;
1587                 int baselen = strlen(base);
1588                 char *log = xmalloc(baselen + 257);
1589
1590                 memcpy(log, base, baselen);
1591                 if (baselen && base[baselen-1] != '/')
1592                         log[baselen++] = '/';
1593
1594                 while ((de = readdir(dir)) != NULL) {
1595                         struct stat st;
1596                         int namelen;
1597
1598                         if (de->d_name[0] == '.')
1599                                 continue;
1600                         namelen = strlen(de->d_name);
1601                         if (namelen > 255)
1602                                 continue;
1603                         if (has_extension(de->d_name, ".lock"))
1604                                 continue;
1605                         memcpy(log + baselen, de->d_name, namelen+1);
1606                         if (stat(git_path("logs/%s", log), &st) < 0)
1607                                 continue;
1608                         if (S_ISDIR(st.st_mode)) {
1609                                 retval = do_for_each_reflog(log, fn, cb_data);
1610                         } else {
1611                                 unsigned char sha1[20];
1612                                 if (!resolve_ref(log, sha1, 0, NULL))
1613                                         retval = error("bad ref for %s", log);
1614                                 else
1615                                         retval = fn(log, sha1, 0, cb_data);
1616                         }
1617                         if (retval)
1618                                 break;
1619                 }
1620                 free(log);
1621                 closedir(dir);
1622         }
1623         else if (*base)
1624                 return errno;
1625         return retval;
1626 }
1627
1628 int for_each_reflog(each_ref_fn fn, void *cb_data)
1629 {
1630         return do_for_each_reflog("", fn, cb_data);
1631 }
1632
1633 int update_ref(const char *action, const char *refname,
1634                 const unsigned char *sha1, const unsigned char *oldval,
1635                 int flags, enum action_on_err onerr)
1636 {
1637         static struct ref_lock *lock;
1638         lock = lock_any_ref_for_update(refname, oldval, flags);
1639         if (!lock) {
1640                 const char *str = "Cannot lock the ref '%s'.";
1641                 switch (onerr) {
1642                 case MSG_ON_ERR: error(str, refname); break;
1643                 case DIE_ON_ERR: die(str, refname); break;
1644                 case QUIET_ON_ERR: break;
1645                 }
1646                 return 1;
1647         }
1648         if (write_ref_sha1(lock, sha1, action) < 0) {
1649                 const char *str = "Cannot update the ref '%s'.";
1650                 switch (onerr) {
1651                 case MSG_ON_ERR: error(str, refname); break;
1652                 case DIE_ON_ERR: die(str, refname); break;
1653                 case QUIET_ON_ERR: break;
1654                 }
1655                 return 1;
1656         }
1657         return 0;
1658 }
1659
1660 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1661 {
1662         for ( ; list; list = list->next)
1663                 if (!strcmp(list->name, name))
1664                         return (struct ref *)list;
1665         return NULL;
1666 }
1667
1668 /*
1669  * generate a format suitable for scanf from a ref_rev_parse_rules
1670  * rule, that is replace the "%.*s" spec with a "%s" spec
1671  */
1672 static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
1673 {
1674         char *spec;
1675
1676         spec = strstr(rule, "%.*s");
1677         if (!spec || strstr(spec + 4, "%.*s"))
1678                 die("invalid rule in ref_rev_parse_rules: %s", rule);
1679
1680         /* copy all until spec */
1681         strncpy(scanf_fmt, rule, spec - rule);
1682         scanf_fmt[spec - rule] = '\0';
1683         /* copy new spec */
1684         strcat(scanf_fmt, "%s");
1685         /* copy remaining rule */
1686         strcat(scanf_fmt, spec + 4);
1687
1688         return;
1689 }
1690
1691 char *shorten_unambiguous_ref(const char *ref, int strict)
1692 {
1693         int i;
1694         static char **scanf_fmts;
1695         static int nr_rules;
1696         char *short_name;
1697
1698         /* pre generate scanf formats from ref_rev_parse_rules[] */
1699         if (!nr_rules) {
1700                 size_t total_len = 0;
1701
1702                 /* the rule list is NULL terminated, count them first */
1703                 for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
1704                         /* no +1 because strlen("%s") < strlen("%.*s") */
1705                         total_len += strlen(ref_rev_parse_rules[nr_rules]);
1706
1707                 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
1708
1709                 total_len = 0;
1710                 for (i = 0; i < nr_rules; i++) {
1711                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
1712                                         + total_len;
1713                         gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
1714                         total_len += strlen(ref_rev_parse_rules[i]);
1715                 }
1716         }
1717
1718         /* bail out if there are no rules */
1719         if (!nr_rules)
1720                 return xstrdup(ref);
1721
1722         /* buffer for scanf result, at most ref must fit */
1723         short_name = xstrdup(ref);
1724
1725         /* skip first rule, it will always match */
1726         for (i = nr_rules - 1; i > 0 ; --i) {
1727                 int j;
1728                 int rules_to_fail = i;
1729                 int short_name_len;
1730
1731                 if (1 != sscanf(ref, scanf_fmts[i], short_name))
1732                         continue;
1733
1734                 short_name_len = strlen(short_name);
1735
1736                 /*
1737                  * in strict mode, all (except the matched one) rules
1738                  * must fail to resolve to a valid non-ambiguous ref
1739                  */
1740                 if (strict)
1741                         rules_to_fail = nr_rules;
1742
1743                 /*
1744                  * check if the short name resolves to a valid ref,
1745                  * but use only rules prior to the matched one
1746                  */
1747                 for (j = 0; j < rules_to_fail; j++) {
1748                         const char *rule = ref_rev_parse_rules[j];
1749                         unsigned char short_objectname[20];
1750                         char refname[PATH_MAX];
1751
1752                         /* skip matched rule */
1753                         if (i == j)
1754                                 continue;
1755
1756                         /*
1757                          * the short name is ambiguous, if it resolves
1758                          * (with this previous rule) to a valid ref
1759                          * read_ref() returns 0 on success
1760                          */
1761                         mksnpath(refname, sizeof(refname),
1762                                  rule, short_name_len, short_name);
1763                         if (!read_ref(refname, short_objectname))
1764                                 break;
1765                 }
1766
1767                 /*
1768                  * short name is non-ambiguous if all previous rules
1769                  * haven't resolved to a valid ref
1770                  */
1771                 if (j == rules_to_fail)
1772                         return short_name;
1773         }
1774
1775         free(short_name);
1776         return xstrdup(ref);
1777 }