git-svn: New flag to emulate empty directories
[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 #define REF_BROKEN 010
10
11 struct ref_list {
12         struct ref_list *next;
13         unsigned char flag; /* ISSYMREF? ISPACKED? */
14         unsigned char sha1[20];
15         unsigned char peeled[20];
16         char name[FLEX_ARRAY];
17 };
18
19 static const char *parse_ref_line(char *line, unsigned char *sha1)
20 {
21         /*
22          * 42: the answer to everything.
23          *
24          * In this case, it happens to be the answer to
25          *  40 (length of sha1 hex representation)
26          *  +1 (space in between hex and name)
27          *  +1 (newline at the end of the line)
28          */
29         int len = strlen(line) - 42;
30
31         if (len <= 0)
32                 return NULL;
33         if (get_sha1_hex(line, sha1) < 0)
34                 return NULL;
35         if (!isspace(line[40]))
36                 return NULL;
37         line += 41;
38         if (isspace(*line))
39                 return NULL;
40         if (line[len] != '\n')
41                 return NULL;
42         line[len] = 0;
43
44         return line;
45 }
46
47 static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
48                                 int flag, struct ref_list *list,
49                                 struct ref_list **new_entry)
50 {
51         int len;
52         struct ref_list *entry;
53
54         /* Allocate it and add it in.. */
55         len = strlen(name) + 1;
56         entry = xmalloc(sizeof(struct ref_list) + len);
57         hashcpy(entry->sha1, sha1);
58         hashclr(entry->peeled);
59         memcpy(entry->name, name, len);
60         entry->flag = flag;
61         entry->next = list;
62         if (new_entry)
63                 *new_entry = entry;
64         return entry;
65 }
66
67 /* merge sort the ref list */
68 static struct ref_list *sort_ref_list(struct ref_list *list)
69 {
70         int psize, qsize, last_merge_count, cmp;
71         struct ref_list *p, *q, *l, *e;
72         struct ref_list *new_list = list;
73         int k = 1;
74         int merge_count = 0;
75
76         if (!list)
77                 return list;
78
79         do {
80                 last_merge_count = merge_count;
81                 merge_count = 0;
82
83                 psize = 0;
84
85                 p = new_list;
86                 q = new_list;
87                 new_list = NULL;
88                 l = NULL;
89
90                 while (p) {
91                         merge_count++;
92
93                         while (psize < k && q->next) {
94                                 q = q->next;
95                                 psize++;
96                         }
97                         qsize = k;
98
99                         while ((psize > 0) || (qsize > 0 && q)) {
100                                 if (qsize == 0 || !q) {
101                                         e = p;
102                                         p = p->next;
103                                         psize--;
104                                 } else if (psize == 0) {
105                                         e = q;
106                                         q = q->next;
107                                         qsize--;
108                                 } else {
109                                         cmp = strcmp(q->name, p->name);
110                                         if (cmp < 0) {
111                                                 e = q;
112                                                 q = q->next;
113                                                 qsize--;
114                                         } else if (cmp > 0) {
115                                                 e = p;
116                                                 p = p->next;
117                                                 psize--;
118                                         } else {
119                                                 if (hashcmp(q->sha1, p->sha1))
120                                                         die("Duplicated ref, and SHA1s don't match: %s",
121                                                             q->name);
122                                                 warning("Duplicated ref: %s", q->name);
123                                                 e = q;
124                                                 q = q->next;
125                                                 qsize--;
126                                                 free(e);
127                                                 e = p;
128                                                 p = p->next;
129                                                 psize--;
130                                         }
131                                 }
132
133                                 e->next = NULL;
134
135                                 if (l)
136                                         l->next = e;
137                                 if (!new_list)
138                                         new_list = e;
139                                 l = e;
140                         }
141
142                         p = q;
143                 };
144
145                 k = k * 2;
146         } while ((last_merge_count != merge_count) || (last_merge_count != 1));
147
148         return new_list;
149 }
150
151 /*
152  * Future: need to be in "struct repository"
153  * when doing a full libification.
154  */
155 static struct cached_refs {
156         char did_loose;
157         char did_packed;
158         struct ref_list *loose;
159         struct ref_list *packed;
160 } cached_refs, submodule_refs;
161 static struct ref_list *current_ref;
162
163 static struct ref_list *extra_refs;
164
165 static void free_ref_list(struct ref_list *list)
166 {
167         struct ref_list *next;
168         for ( ; list; list = next) {
169                 next = list->next;
170                 free(list);
171         }
172 }
173
174 static void invalidate_cached_refs(void)
175 {
176         struct cached_refs *ca = &cached_refs;
177
178         if (ca->did_loose && ca->loose)
179                 free_ref_list(ca->loose);
180         if (ca->did_packed && ca->packed)
181                 free_ref_list(ca->packed);
182         ca->loose = ca->packed = NULL;
183         ca->did_loose = ca->did_packed = 0;
184 }
185
186 static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
187 {
188         struct ref_list *list = NULL;
189         struct ref_list *last = NULL;
190         char refline[PATH_MAX];
191         int flag = REF_ISPACKED;
192
193         while (fgets(refline, sizeof(refline), f)) {
194                 unsigned char sha1[20];
195                 const char *name;
196                 static const char header[] = "# pack-refs with:";
197
198                 if (!strncmp(refline, header, sizeof(header)-1)) {
199                         const char *traits = refline + sizeof(header) - 1;
200                         if (strstr(traits, " peeled "))
201                                 flag |= REF_KNOWS_PEELED;
202                         /* perhaps other traits later as well */
203                         continue;
204                 }
205
206                 name = parse_ref_line(refline, sha1);
207                 if (name) {
208                         list = add_ref(name, sha1, flag, list, &last);
209                         continue;
210                 }
211                 if (last &&
212                     refline[0] == '^' &&
213                     strlen(refline) == 42 &&
214                     refline[41] == '\n' &&
215                     !get_sha1_hex(refline + 1, sha1))
216                         hashcpy(last->peeled, sha1);
217         }
218         cached_refs->packed = sort_ref_list(list);
219 }
220
221 void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
222 {
223         extra_refs = add_ref(name, sha1, flag, extra_refs, NULL);
224 }
225
226 void clear_extra_refs(void)
227 {
228         free_ref_list(extra_refs);
229         extra_refs = NULL;
230 }
231
232 static struct ref_list *get_packed_refs(const char *submodule)
233 {
234         const char *packed_refs_file;
235         struct cached_refs *refs;
236
237         if (submodule) {
238                 packed_refs_file = git_path_submodule(submodule, "packed-refs");
239                 refs = &submodule_refs;
240                 free_ref_list(refs->packed);
241         } else {
242                 packed_refs_file = git_path("packed-refs");
243                 refs = &cached_refs;
244         }
245
246         if (!refs->did_packed || submodule) {
247                 FILE *f = fopen(packed_refs_file, "r");
248                 refs->packed = NULL;
249                 if (f) {
250                         read_packed_refs(f, refs);
251                         fclose(f);
252                 }
253                 refs->did_packed = 1;
254         }
255         return refs->packed;
256 }
257
258 static struct ref_list *get_ref_dir(const char *submodule, const char *base,
259                                     struct ref_list *list)
260 {
261         DIR *dir;
262         const char *path;
263
264         if (submodule)
265                 path = git_path_submodule(submodule, "%s", base);
266         else
267                 path = git_path("%s", base);
268
269
270         dir = opendir(path);
271
272         if (dir) {
273                 struct dirent *de;
274                 int baselen = strlen(base);
275                 char *ref = xmalloc(baselen + 257);
276
277                 memcpy(ref, base, baselen);
278                 if (baselen && base[baselen-1] != '/')
279                         ref[baselen++] = '/';
280
281                 while ((de = readdir(dir)) != NULL) {
282                         unsigned char sha1[20];
283                         struct stat st;
284                         int flag;
285                         int namelen;
286                         const char *refdir;
287
288                         if (de->d_name[0] == '.')
289                                 continue;
290                         namelen = strlen(de->d_name);
291                         if (namelen > 255)
292                                 continue;
293                         if (has_extension(de->d_name, ".lock"))
294                                 continue;
295                         memcpy(ref + baselen, de->d_name, namelen+1);
296                         refdir = submodule
297                                 ? git_path_submodule(submodule, "%s", ref)
298                                 : git_path("%s", ref);
299                         if (stat(refdir, &st) < 0)
300                                 continue;
301                         if (S_ISDIR(st.st_mode)) {
302                                 list = get_ref_dir(submodule, ref, list);
303                                 continue;
304                         }
305                         if (submodule) {
306                                 hashclr(sha1);
307                                 flag = 0;
308                                 if (resolve_gitlink_ref(submodule, ref, sha1) < 0) {
309                                         hashclr(sha1);
310                                         flag |= REF_BROKEN;
311                                 }
312                         } else
313                                 if (!resolve_ref(ref, sha1, 1, &flag)) {
314                                         hashclr(sha1);
315                                         flag |= REF_BROKEN;
316                                 }
317                         list = add_ref(ref, sha1, flag, list, NULL);
318                 }
319                 free(ref);
320                 closedir(dir);
321         }
322         return sort_ref_list(list);
323 }
324
325 struct warn_if_dangling_data {
326         FILE *fp;
327         const char *refname;
328         const char *msg_fmt;
329 };
330
331 static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
332                                    int flags, void *cb_data)
333 {
334         struct warn_if_dangling_data *d = cb_data;
335         const char *resolves_to;
336         unsigned char junk[20];
337
338         if (!(flags & REF_ISSYMREF))
339                 return 0;
340
341         resolves_to = resolve_ref(refname, junk, 0, NULL);
342         if (!resolves_to || strcmp(resolves_to, d->refname))
343                 return 0;
344
345         fprintf(d->fp, d->msg_fmt, refname);
346         return 0;
347 }
348
349 void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
350 {
351         struct warn_if_dangling_data data;
352
353         data.fp = fp;
354         data.refname = refname;
355         data.msg_fmt = msg_fmt;
356         for_each_rawref(warn_if_dangling_symref, &data);
357 }
358
359 static struct ref_list *get_loose_refs(const char *submodule)
360 {
361         if (submodule) {
362                 free_ref_list(submodule_refs.loose);
363                 submodule_refs.loose = get_ref_dir(submodule, "refs", NULL);
364                 return submodule_refs.loose;
365         }
366
367         if (!cached_refs.did_loose) {
368                 cached_refs.loose = get_ref_dir(NULL, "refs", NULL);
369                 cached_refs.did_loose = 1;
370         }
371         return cached_refs.loose;
372 }
373
374 /* We allow "recursive" symbolic refs. Only within reason, though */
375 #define MAXDEPTH 5
376 #define MAXREFLEN (1024)
377
378 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
379 {
380         FILE *f;
381         struct cached_refs refs;
382         struct ref_list *ref;
383         int retval;
384
385         strcpy(name + pathlen, "packed-refs");
386         f = fopen(name, "r");
387         if (!f)
388                 return -1;
389         read_packed_refs(f, &refs);
390         fclose(f);
391         ref = refs.packed;
392         retval = -1;
393         while (ref) {
394                 if (!strcmp(ref->name, refname)) {
395                         retval = 0;
396                         memcpy(result, ref->sha1, 20);
397                         break;
398                 }
399                 ref = ref->next;
400         }
401         free_ref_list(refs.packed);
402         return retval;
403 }
404
405 static int resolve_gitlink_ref_recursive(char *name, int pathlen, const char *refname, unsigned char *result, int recursion)
406 {
407         int fd, len = strlen(refname);
408         char buffer[128], *p;
409
410         if (recursion > MAXDEPTH || len > MAXREFLEN)
411                 return -1;
412         memcpy(name + pathlen, refname, len+1);
413         fd = open(name, O_RDONLY);
414         if (fd < 0)
415                 return resolve_gitlink_packed_ref(name, pathlen, refname, result);
416
417         len = read(fd, buffer, sizeof(buffer)-1);
418         close(fd);
419         if (len < 0)
420                 return -1;
421         while (len && isspace(buffer[len-1]))
422                 len--;
423         buffer[len] = 0;
424
425         /* Was it a detached head or an old-fashioned symlink? */
426         if (!get_sha1_hex(buffer, result))
427                 return 0;
428
429         /* Symref? */
430         if (strncmp(buffer, "ref:", 4))
431                 return -1;
432         p = buffer + 4;
433         while (isspace(*p))
434                 p++;
435
436         return resolve_gitlink_ref_recursive(name, pathlen, p, result, recursion+1);
437 }
438
439 int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *result)
440 {
441         int len = strlen(path), retval;
442         char *gitdir;
443         const char *tmp;
444
445         while (len && path[len-1] == '/')
446                 len--;
447         if (!len)
448                 return -1;
449         gitdir = xmalloc(len + MAXREFLEN + 8);
450         memcpy(gitdir, path, len);
451         memcpy(gitdir + len, "/.git", 6);
452         len += 5;
453
454         tmp = read_gitfile(gitdir);
455         if (tmp) {
456                 free(gitdir);
457                 len = strlen(tmp);
458                 gitdir = xmalloc(len + MAXREFLEN + 3);
459                 memcpy(gitdir, tmp, len);
460         }
461         gitdir[len] = '/';
462         gitdir[++len] = '\0';
463         retval = resolve_gitlink_ref_recursive(gitdir, len, refname, result, 0);
464         free(gitdir);
465         return retval;
466 }
467
468 /*
469  * If the "reading" argument is set, this function finds out what _object_
470  * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
471  * has to exist, and if it is symbolic, it has to point at an existing ref,
472  * because the "read" goes through the symref to the ref it points at.
473  *
474  * The access that is not "reading" may often be "writing", but does not
475  * have to; it can be merely checking _where it leads to_. If it is a
476  * prelude to "writing" to the ref, a write to a symref that points at
477  * yet-to-be-born ref will create the real ref pointed by the symref.
478  * reading=0 allows the caller to check where such a symref leads to.
479  */
480 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
481 {
482         int depth = MAXDEPTH;
483         ssize_t len;
484         char buffer[256];
485         static char ref_buffer[256];
486
487         if (flag)
488                 *flag = 0;
489
490         for (;;) {
491                 char path[PATH_MAX];
492                 struct stat st;
493                 char *buf;
494                 int fd;
495
496                 if (--depth < 0)
497                         return NULL;
498
499                 git_snpath(path, sizeof(path), "%s", ref);
500                 /* Special case: non-existing file. */
501                 if (lstat(path, &st) < 0) {
502                         struct ref_list *list = get_packed_refs(NULL);
503                         while (list) {
504                                 if (!strcmp(ref, list->name)) {
505                                         hashcpy(sha1, list->sha1);
506                                         if (flag)
507                                                 *flag |= REF_ISPACKED;
508                                         return ref;
509                                 }
510                                 list = list->next;
511                         }
512                         if (reading || errno != ENOENT)
513                                 return NULL;
514                         hashclr(sha1);
515                         return ref;
516                 }
517
518                 /* Follow "normalized" - ie "refs/.." symlinks by hand */
519                 if (S_ISLNK(st.st_mode)) {
520                         len = readlink(path, buffer, sizeof(buffer)-1);
521                         if (len >= 5 && !memcmp("refs/", buffer, 5)) {
522                                 buffer[len] = 0;
523                                 strcpy(ref_buffer, buffer);
524                                 ref = ref_buffer;
525                                 if (flag)
526                                         *flag |= REF_ISSYMREF;
527                                 continue;
528                         }
529                 }
530
531                 /* Is it a directory? */
532                 if (S_ISDIR(st.st_mode)) {
533                         errno = EISDIR;
534                         return NULL;
535                 }
536
537                 /*
538                  * Anything else, just open it and try to use it as
539                  * a ref
540                  */
541                 fd = open(path, O_RDONLY);
542                 if (fd < 0)
543                         return NULL;
544                 len = read_in_full(fd, buffer, sizeof(buffer)-1);
545                 close(fd);
546
547                 /*
548                  * Is it a symbolic ref?
549                  */
550                 if (len < 4 || memcmp("ref:", buffer, 4))
551                         break;
552                 buf = buffer + 4;
553                 len -= 4;
554                 while (len && isspace(*buf))
555                         buf++, len--;
556                 while (len && isspace(buf[len-1]))
557                         len--;
558                 buf[len] = 0;
559                 memcpy(ref_buffer, buf, len + 1);
560                 ref = ref_buffer;
561                 if (flag)
562                         *flag |= REF_ISSYMREF;
563         }
564         if (len < 40 || get_sha1_hex(buffer, sha1))
565                 return NULL;
566         return ref;
567 }
568
569 /* The argument to filter_refs */
570 struct ref_filter {
571         const char *pattern;
572         each_ref_fn *fn;
573         void *cb_data;
574 };
575
576 int read_ref(const char *ref, unsigned char *sha1)
577 {
578         if (resolve_ref(ref, sha1, 1, NULL))
579                 return 0;
580         return -1;
581 }
582
583 #define DO_FOR_EACH_INCLUDE_BROKEN 01
584 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
585                       int flags, void *cb_data, struct ref_list *entry)
586 {
587         if (prefixcmp(entry->name, base))
588                 return 0;
589
590         if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
591                 if (entry->flag & REF_BROKEN)
592                         return 0; /* ignore dangling symref */
593                 if (!has_sha1_file(entry->sha1)) {
594                         error("%s does not point to a valid object!", entry->name);
595                         return 0;
596                 }
597         }
598         current_ref = entry;
599         return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
600 }
601
602 static int filter_refs(const char *ref, const unsigned char *sha, int flags,
603         void *data)
604 {
605         struct ref_filter *filter = (struct ref_filter *)data;
606         if (fnmatch(filter->pattern, ref, 0))
607                 return 0;
608         return filter->fn(ref, sha, flags, filter->cb_data);
609 }
610
611 int peel_ref(const char *ref, unsigned char *sha1)
612 {
613         int flag;
614         unsigned char base[20];
615         struct object *o;
616
617         if (current_ref && (current_ref->name == ref
618                 || !strcmp(current_ref->name, ref))) {
619                 if (current_ref->flag & REF_KNOWS_PEELED) {
620                         hashcpy(sha1, current_ref->peeled);
621                         return 0;
622                 }
623                 hashcpy(base, current_ref->sha1);
624                 goto fallback;
625         }
626
627         if (!resolve_ref(ref, base, 1, &flag))
628                 return -1;
629
630         if ((flag & REF_ISPACKED)) {
631                 struct ref_list *list = get_packed_refs(NULL);
632
633                 while (list) {
634                         if (!strcmp(list->name, ref)) {
635                                 if (list->flag & REF_KNOWS_PEELED) {
636                                         hashcpy(sha1, list->peeled);
637                                         return 0;
638                                 }
639                                 /* older pack-refs did not leave peeled ones */
640                                 break;
641                         }
642                         list = list->next;
643                 }
644         }
645
646 fallback:
647         o = parse_object(base);
648         if (o && o->type == OBJ_TAG) {
649                 o = deref_tag(o, ref, 0);
650                 if (o) {
651                         hashcpy(sha1, o->sha1);
652                         return 0;
653                 }
654         }
655         return -1;
656 }
657
658 static int do_for_each_ref(const char *submodule, const char *base, each_ref_fn fn,
659                            int trim, int flags, void *cb_data)
660 {
661         int retval = 0;
662         struct ref_list *packed = get_packed_refs(submodule);
663         struct ref_list *loose = get_loose_refs(submodule);
664
665         struct ref_list *extra;
666
667         for (extra = extra_refs; extra; extra = extra->next)
668                 retval = do_one_ref(base, fn, trim, flags, cb_data, extra);
669
670         while (packed && loose) {
671                 struct ref_list *entry;
672                 int cmp = strcmp(packed->name, loose->name);
673                 if (!cmp) {
674                         packed = packed->next;
675                         continue;
676                 }
677                 if (cmp > 0) {
678                         entry = loose;
679                         loose = loose->next;
680                 } else {
681                         entry = packed;
682                         packed = packed->next;
683                 }
684                 retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
685                 if (retval)
686                         goto end_each;
687         }
688
689         for (packed = packed ? packed : loose; packed; packed = packed->next) {
690                 retval = do_one_ref(base, fn, trim, flags, cb_data, packed);
691                 if (retval)
692                         goto end_each;
693         }
694
695 end_each:
696         current_ref = NULL;
697         return retval;
698 }
699
700
701 static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
702 {
703         unsigned char sha1[20];
704         int flag;
705
706         if (submodule) {
707                 if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
708                         return fn("HEAD", sha1, 0, cb_data);
709
710                 return 0;
711         }
712
713         if (resolve_ref("HEAD", sha1, 1, &flag))
714                 return fn("HEAD", sha1, flag, cb_data);
715
716         return 0;
717 }
718
719 int head_ref(each_ref_fn fn, void *cb_data)
720 {
721         return do_head_ref(NULL, fn, cb_data);
722 }
723
724 int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
725 {
726         return do_head_ref(submodule, fn, cb_data);
727 }
728
729 int for_each_ref(each_ref_fn fn, void *cb_data)
730 {
731         return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
732 }
733
734 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
735 {
736         return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
737 }
738
739 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
740 {
741         return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
742 }
743
744 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
745                 each_ref_fn fn, void *cb_data)
746 {
747         return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
748 }
749
750 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
751 {
752         return for_each_ref_in("refs/tags/", fn, cb_data);
753 }
754
755 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
756 {
757         return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
758 }
759
760 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
761 {
762         return for_each_ref_in("refs/heads/", fn, cb_data);
763 }
764
765 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
766 {
767         return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
768 }
769
770 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
771 {
772         return for_each_ref_in("refs/remotes/", fn, cb_data);
773 }
774
775 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
776 {
777         return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
778 }
779
780 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
781 {
782         return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
783 }
784
785 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
786 {
787         struct strbuf buf = STRBUF_INIT;
788         int ret = 0;
789         unsigned char sha1[20];
790         int flag;
791
792         strbuf_addf(&buf, "%sHEAD", get_git_namespace());
793         if (resolve_ref(buf.buf, sha1, 1, &flag))
794                 ret = fn(buf.buf, sha1, flag, cb_data);
795         strbuf_release(&buf);
796
797         return ret;
798 }
799
800 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
801 {
802         struct strbuf buf = STRBUF_INIT;
803         int ret;
804         strbuf_addf(&buf, "%srefs/", get_git_namespace());
805         ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
806         strbuf_release(&buf);
807         return ret;
808 }
809
810 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
811         const char *prefix, void *cb_data)
812 {
813         struct strbuf real_pattern = STRBUF_INIT;
814         struct ref_filter filter;
815         int ret;
816
817         if (!prefix && prefixcmp(pattern, "refs/"))
818                 strbuf_addstr(&real_pattern, "refs/");
819         else if (prefix)
820                 strbuf_addstr(&real_pattern, prefix);
821         strbuf_addstr(&real_pattern, pattern);
822
823         if (!has_glob_specials(pattern)) {
824                 /* Append implied '/' '*' if not present. */
825                 if (real_pattern.buf[real_pattern.len - 1] != '/')
826                         strbuf_addch(&real_pattern, '/');
827                 /* No need to check for '*', there is none. */
828                 strbuf_addch(&real_pattern, '*');
829         }
830
831         filter.pattern = real_pattern.buf;
832         filter.fn = fn;
833         filter.cb_data = cb_data;
834         ret = for_each_ref(filter_refs, &filter);
835
836         strbuf_release(&real_pattern);
837         return ret;
838 }
839
840 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
841 {
842         return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
843 }
844
845 int for_each_rawref(each_ref_fn fn, void *cb_data)
846 {
847         return do_for_each_ref(NULL, "", fn, 0,
848                                DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
849 }
850
851 /*
852  * Make sure "ref" is something reasonable to have under ".git/refs/";
853  * We do not like it if:
854  *
855  * - any path component of it begins with ".", or
856  * - it has double dots "..", or
857  * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
858  * - it ends with a "/".
859  * - it ends with ".lock"
860  * - it contains a "\" (backslash)
861  */
862
863 static inline int bad_ref_char(int ch)
864 {
865         if (((unsigned) ch) <= ' ' ||
866             ch == '~' || ch == '^' || ch == ':' || ch == '\\')
867                 return 1;
868         /* 2.13 Pattern Matching Notation */
869         if (ch == '?' || ch == '[') /* Unsupported */
870                 return 1;
871         if (ch == '*') /* Supported at the end */
872                 return 2;
873         return 0;
874 }
875
876 int check_ref_format(const char *ref)
877 {
878         int ch, level, bad_type, last;
879         int ret = CHECK_REF_FORMAT_OK;
880         const char *cp = ref;
881
882         level = 0;
883         while (1) {
884                 while ((ch = *cp++) == '/')
885                         ; /* tolerate duplicated slashes */
886                 if (!ch)
887                         /* should not end with slashes */
888                         return CHECK_REF_FORMAT_ERROR;
889
890                 /* we are at the beginning of the path component */
891                 if (ch == '.')
892                         return CHECK_REF_FORMAT_ERROR;
893                 bad_type = bad_ref_char(ch);
894                 if (bad_type) {
895                         if (bad_type == 2 && (!*cp || *cp == '/') &&
896                             ret == CHECK_REF_FORMAT_OK)
897                                 ret = CHECK_REF_FORMAT_WILDCARD;
898                         else
899                                 return CHECK_REF_FORMAT_ERROR;
900                 }
901
902                 last = ch;
903                 /* scan the rest of the path component */
904                 while ((ch = *cp++) != 0) {
905                         bad_type = bad_ref_char(ch);
906                         if (bad_type)
907                                 return CHECK_REF_FORMAT_ERROR;
908                         if (ch == '/')
909                                 break;
910                         if (last == '.' && ch == '.')
911                                 return CHECK_REF_FORMAT_ERROR;
912                         if (last == '@' && ch == '{')
913                                 return CHECK_REF_FORMAT_ERROR;
914                         last = ch;
915                 }
916                 level++;
917                 if (!ch) {
918                         if (ref <= cp - 2 && cp[-2] == '.')
919                                 return CHECK_REF_FORMAT_ERROR;
920                         if (level < 2)
921                                 return CHECK_REF_FORMAT_ONELEVEL;
922                         if (has_extension(ref, ".lock"))
923                                 return CHECK_REF_FORMAT_ERROR;
924                         return ret;
925                 }
926         }
927 }
928
929 const char *prettify_refname(const char *name)
930 {
931         return name + (
932                 !prefixcmp(name, "refs/heads/") ? 11 :
933                 !prefixcmp(name, "refs/tags/") ? 10 :
934                 !prefixcmp(name, "refs/remotes/") ? 13 :
935                 0);
936 }
937
938 const char *ref_rev_parse_rules[] = {
939         "%.*s",
940         "refs/%.*s",
941         "refs/tags/%.*s",
942         "refs/heads/%.*s",
943         "refs/remotes/%.*s",
944         "refs/remotes/%.*s/HEAD",
945         NULL
946 };
947
948 const char *ref_fetch_rules[] = {
949         "%.*s",
950         "refs/%.*s",
951         "refs/heads/%.*s",
952         NULL
953 };
954
955 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
956 {
957         const char **p;
958         const int abbrev_name_len = strlen(abbrev_name);
959
960         for (p = rules; *p; p++) {
961                 if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
962                         return 1;
963                 }
964         }
965
966         return 0;
967 }
968
969 static struct ref_lock *verify_lock(struct ref_lock *lock,
970         const unsigned char *old_sha1, int mustexist)
971 {
972         if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
973                 error("Can't verify ref %s", lock->ref_name);
974                 unlock_ref(lock);
975                 return NULL;
976         }
977         if (hashcmp(lock->old_sha1, old_sha1)) {
978                 error("Ref %s is at %s but expected %s", lock->ref_name,
979                         sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
980                 unlock_ref(lock);
981                 return NULL;
982         }
983         return lock;
984 }
985
986 static int remove_empty_directories(const char *file)
987 {
988         /* we want to create a file but there is a directory there;
989          * if that is an empty directory (or a directory that contains
990          * only empty directories), remove them.
991          */
992         struct strbuf path;
993         int result;
994
995         strbuf_init(&path, 20);
996         strbuf_addstr(&path, file);
997
998         result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
999
1000         strbuf_release(&path);
1001
1002         return result;
1003 }
1004
1005 static int is_refname_available(const char *ref, const char *oldref,
1006                                 struct ref_list *list, int quiet)
1007 {
1008         int namlen = strlen(ref); /* e.g. 'foo/bar' */
1009         while (list) {
1010                 /* list->name could be 'foo' or 'foo/bar/baz' */
1011                 if (!oldref || strcmp(oldref, list->name)) {
1012                         int len = strlen(list->name);
1013                         int cmplen = (namlen < len) ? namlen : len;
1014                         const char *lead = (namlen < len) ? list->name : ref;
1015                         if (!strncmp(ref, list->name, cmplen) &&
1016                             lead[cmplen] == '/') {
1017                                 if (!quiet)
1018                                         error("'%s' exists; cannot create '%s'",
1019                                               list->name, ref);
1020                                 return 0;
1021                         }
1022                 }
1023                 list = list->next;
1024         }
1025         return 1;
1026 }
1027
1028 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
1029 {
1030         char *ref_file;
1031         const char *orig_ref = ref;
1032         struct ref_lock *lock;
1033         int last_errno = 0;
1034         int type, lflags;
1035         int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1036         int missing = 0;
1037
1038         lock = xcalloc(1, sizeof(struct ref_lock));
1039         lock->lock_fd = -1;
1040
1041         ref = resolve_ref(ref, lock->old_sha1, mustexist, &type);
1042         if (!ref && errno == EISDIR) {
1043                 /* we are trying to lock foo but we used to
1044                  * have foo/bar which now does not exist;
1045                  * it is normal for the empty directory 'foo'
1046                  * to remain.
1047                  */
1048                 ref_file = git_path("%s", orig_ref);
1049                 if (remove_empty_directories(ref_file)) {
1050                         last_errno = errno;
1051                         error("there are still refs under '%s'", orig_ref);
1052                         goto error_return;
1053                 }
1054                 ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, &type);
1055         }
1056         if (type_p)
1057             *type_p = type;
1058         if (!ref) {
1059                 last_errno = errno;
1060                 error("unable to resolve reference %s: %s",
1061                         orig_ref, strerror(errno));
1062                 goto error_return;
1063         }
1064         missing = is_null_sha1(lock->old_sha1);
1065         /* When the ref did not exist and we are creating it,
1066          * make sure there is no existing ref that is packed
1067          * whose name begins with our refname, nor a ref whose
1068          * name is a proper prefix of our refname.
1069          */
1070         if (missing &&
1071              !is_refname_available(ref, NULL, get_packed_refs(NULL), 0)) {
1072                 last_errno = ENOTDIR;
1073                 goto error_return;
1074         }
1075
1076         lock->lk = xcalloc(1, sizeof(struct lock_file));
1077
1078         lflags = LOCK_DIE_ON_ERROR;
1079         if (flags & REF_NODEREF) {
1080                 ref = orig_ref;
1081                 lflags |= LOCK_NODEREF;
1082         }
1083         lock->ref_name = xstrdup(ref);
1084         lock->orig_ref_name = xstrdup(orig_ref);
1085         ref_file = git_path("%s", ref);
1086         if (missing)
1087                 lock->force_write = 1;
1088         if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
1089                 lock->force_write = 1;
1090
1091         if (safe_create_leading_directories(ref_file)) {
1092                 last_errno = errno;
1093                 error("unable to create directory for %s", ref_file);
1094                 goto error_return;
1095         }
1096
1097         lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
1098         return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
1099
1100  error_return:
1101         unlock_ref(lock);
1102         errno = last_errno;
1103         return NULL;
1104 }
1105
1106 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
1107 {
1108         char refpath[PATH_MAX];
1109         if (check_ref_format(ref))
1110                 return NULL;
1111         strcpy(refpath, mkpath("refs/%s", ref));
1112         return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1113 }
1114
1115 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
1116 {
1117         switch (check_ref_format(ref)) {
1118         default:
1119                 return NULL;
1120         case 0:
1121         case CHECK_REF_FORMAT_ONELEVEL:
1122                 return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
1123         }
1124 }
1125
1126 static struct lock_file packlock;
1127
1128 static int repack_without_ref(const char *refname)
1129 {
1130         struct ref_list *list, *packed_ref_list;
1131         int fd;
1132         int found = 0;
1133
1134         packed_ref_list = get_packed_refs(NULL);
1135         for (list = packed_ref_list; list; list = list->next) {
1136                 if (!strcmp(refname, list->name)) {
1137                         found = 1;
1138                         break;
1139                 }
1140         }
1141         if (!found)
1142                 return 0;
1143         fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1144         if (fd < 0) {
1145                 unable_to_lock_error(git_path("packed-refs"), errno);
1146                 return error("cannot delete '%s' from packed refs", refname);
1147         }
1148
1149         for (list = packed_ref_list; list; list = list->next) {
1150                 char line[PATH_MAX + 100];
1151                 int len;
1152
1153                 if (!strcmp(refname, list->name))
1154                         continue;
1155                 len = snprintf(line, sizeof(line), "%s %s\n",
1156                                sha1_to_hex(list->sha1), list->name);
1157                 /* this should not happen but just being defensive */
1158                 if (len > sizeof(line))
1159                         die("too long a refname '%s'", list->name);
1160                 write_or_die(fd, line, len);
1161         }
1162         return commit_lock_file(&packlock);
1163 }
1164
1165 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1166 {
1167         struct ref_lock *lock;
1168         int err, i = 0, ret = 0, flag = 0;
1169
1170         lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1171         if (!lock)
1172                 return 1;
1173         if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1174                 /* loose */
1175                 const char *path;
1176
1177                 if (!(delopt & REF_NODEREF)) {
1178                         i = strlen(lock->lk->filename) - 5; /* .lock */
1179                         lock->lk->filename[i] = 0;
1180                         path = lock->lk->filename;
1181                 } else {
1182                         path = git_path("%s", refname);
1183                 }
1184                 err = unlink_or_warn(path);
1185                 if (err && errno != ENOENT)
1186                         ret = 1;
1187
1188                 if (!(delopt & REF_NODEREF))
1189                         lock->lk->filename[i] = '.';
1190         }
1191         /* removing the loose one could have resurrected an earlier
1192          * packed one.  Also, if it was not loose we need to repack
1193          * without it.
1194          */
1195         ret |= repack_without_ref(refname);
1196
1197         unlink_or_warn(git_path("logs/%s", lock->ref_name));
1198         invalidate_cached_refs();
1199         unlock_ref(lock);
1200         return ret;
1201 }
1202
1203 /*
1204  * People using contrib's git-new-workdir have .git/logs/refs ->
1205  * /some/other/path/.git/logs/refs, and that may live on another device.
1206  *
1207  * IOW, to avoid cross device rename errors, the temporary renamed log must
1208  * live into logs/refs.
1209  */
1210 #define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
1211
1212 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
1213 {
1214         static const char renamed_ref[] = "RENAMED-REF";
1215         unsigned char sha1[20], orig_sha1[20];
1216         int flag = 0, logmoved = 0;
1217         struct ref_lock *lock;
1218         struct stat loginfo;
1219         int log = !lstat(git_path("logs/%s", oldref), &loginfo);
1220         const char *symref = NULL;
1221
1222         if (log && S_ISLNK(loginfo.st_mode))
1223                 return error("reflog for %s is a symlink", oldref);
1224
1225         symref = resolve_ref(oldref, orig_sha1, 1, &flag);
1226         if (flag & REF_ISSYMREF)
1227                 return error("refname %s is a symbolic ref, renaming it is not supported",
1228                         oldref);
1229         if (!symref)
1230                 return error("refname %s not found", oldref);
1231
1232         if (!is_refname_available(newref, oldref, get_packed_refs(NULL), 0))
1233                 return 1;
1234
1235         if (!is_refname_available(newref, oldref, get_loose_refs(NULL), 0))
1236                 return 1;
1237
1238         lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
1239         if (!lock)
1240                 return error("unable to lock %s", renamed_ref);
1241         lock->force_write = 1;
1242         if (write_ref_sha1(lock, orig_sha1, logmsg))
1243                 return error("unable to save current sha1 in %s", renamed_ref);
1244
1245         if (log && rename(git_path("logs/%s", oldref), git_path(TMP_RENAMED_LOG)))
1246                 return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
1247                         oldref, strerror(errno));
1248
1249         if (delete_ref(oldref, orig_sha1, REF_NODEREF)) {
1250                 error("unable to delete old %s", oldref);
1251                 goto rollback;
1252         }
1253
1254         if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
1255                 if (errno==EISDIR) {
1256                         if (remove_empty_directories(git_path("%s", newref))) {
1257                                 error("Directory not empty: %s", newref);
1258                                 goto rollback;
1259                         }
1260                 } else {
1261                         error("unable to delete existing %s", newref);
1262                         goto rollback;
1263                 }
1264         }
1265
1266         if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
1267                 error("unable to create directory for %s", newref);
1268                 goto rollback;
1269         }
1270
1271  retry:
1272         if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newref))) {
1273                 if (errno==EISDIR || errno==ENOTDIR) {
1274                         /*
1275                          * rename(a, b) when b is an existing
1276                          * directory ought to result in ISDIR, but
1277                          * Solaris 5.8 gives ENOTDIR.  Sheesh.
1278                          */
1279                         if (remove_empty_directories(git_path("logs/%s", newref))) {
1280                                 error("Directory not empty: logs/%s", newref);
1281                                 goto rollback;
1282                         }
1283                         goto retry;
1284                 } else {
1285                         error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
1286                                 newref, strerror(errno));
1287                         goto rollback;
1288                 }
1289         }
1290         logmoved = log;
1291
1292         lock = lock_ref_sha1_basic(newref, NULL, 0, NULL);
1293         if (!lock) {
1294                 error("unable to lock %s for update", newref);
1295                 goto rollback;
1296         }
1297         lock->force_write = 1;
1298         hashcpy(lock->old_sha1, orig_sha1);
1299         if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1300                 error("unable to write current sha1 into %s", newref);
1301                 goto rollback;
1302         }
1303
1304         return 0;
1305
1306  rollback:
1307         lock = lock_ref_sha1_basic(oldref, NULL, 0, NULL);
1308         if (!lock) {
1309                 error("unable to lock %s for rollback", oldref);
1310                 goto rollbacklog;
1311         }
1312
1313         lock->force_write = 1;
1314         flag = log_all_ref_updates;
1315         log_all_ref_updates = 0;
1316         if (write_ref_sha1(lock, orig_sha1, NULL))
1317                 error("unable to write current sha1 into %s", oldref);
1318         log_all_ref_updates = flag;
1319
1320  rollbacklog:
1321         if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
1322                 error("unable to restore logfile %s from %s: %s",
1323                         oldref, newref, strerror(errno));
1324         if (!logmoved && log &&
1325             rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldref)))
1326                 error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
1327                         oldref, strerror(errno));
1328
1329         return 1;
1330 }
1331
1332 int close_ref(struct ref_lock *lock)
1333 {
1334         if (close_lock_file(lock->lk))
1335                 return -1;
1336         lock->lock_fd = -1;
1337         return 0;
1338 }
1339
1340 int commit_ref(struct ref_lock *lock)
1341 {
1342         if (commit_lock_file(lock->lk))
1343                 return -1;
1344         lock->lock_fd = -1;
1345         return 0;
1346 }
1347
1348 void unlock_ref(struct ref_lock *lock)
1349 {
1350         /* Do not free lock->lk -- atexit() still looks at them */
1351         if (lock->lk)
1352                 rollback_lock_file(lock->lk);
1353         free(lock->ref_name);
1354         free(lock->orig_ref_name);
1355         free(lock);
1356 }
1357
1358 /*
1359  * copy the reflog message msg to buf, which has been allocated sufficiently
1360  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1361  * because reflog file is one line per entry.
1362  */
1363 static int copy_msg(char *buf, const char *msg)
1364 {
1365         char *cp = buf;
1366         char c;
1367         int wasspace = 1;
1368
1369         *cp++ = '\t';
1370         while ((c = *msg++)) {
1371                 if (wasspace && isspace(c))
1372                         continue;
1373                 wasspace = isspace(c);
1374                 if (wasspace)
1375                         c = ' ';
1376                 *cp++ = c;
1377         }
1378         while (buf < cp && isspace(cp[-1]))
1379                 cp--;
1380         *cp++ = '\n';
1381         return cp - buf;
1382 }
1383
1384 int log_ref_setup(const char *ref_name, char *logfile, int bufsize)
1385 {
1386         int logfd, oflags = O_APPEND | O_WRONLY;
1387
1388         git_snpath(logfile, bufsize, "logs/%s", ref_name);
1389         if (log_all_ref_updates &&
1390             (!prefixcmp(ref_name, "refs/heads/") ||
1391              !prefixcmp(ref_name, "refs/remotes/") ||
1392              !prefixcmp(ref_name, "refs/notes/") ||
1393              !strcmp(ref_name, "HEAD"))) {
1394                 if (safe_create_leading_directories(logfile) < 0)
1395                         return error("unable to create directory for %s",
1396                                      logfile);
1397                 oflags |= O_CREAT;
1398         }
1399
1400         logfd = open(logfile, oflags, 0666);
1401         if (logfd < 0) {
1402                 if (!(oflags & O_CREAT) && errno == ENOENT)
1403                         return 0;
1404
1405                 if ((oflags & O_CREAT) && errno == EISDIR) {
1406                         if (remove_empty_directories(logfile)) {
1407                                 return error("There are still logs under '%s'",
1408                                              logfile);
1409                         }
1410                         logfd = open(logfile, oflags, 0666);
1411                 }
1412
1413                 if (logfd < 0)
1414                         return error("Unable to append to %s: %s",
1415                                      logfile, strerror(errno));
1416         }
1417
1418         adjust_shared_perm(logfile);
1419         close(logfd);
1420         return 0;
1421 }
1422
1423 static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
1424                          const unsigned char *new_sha1, const char *msg)
1425 {
1426         int logfd, result, written, oflags = O_APPEND | O_WRONLY;
1427         unsigned maxlen, len;
1428         int msglen;
1429         char log_file[PATH_MAX];
1430         char *logrec;
1431         const char *committer;
1432
1433         if (log_all_ref_updates < 0)
1434                 log_all_ref_updates = !is_bare_repository();
1435
1436         result = log_ref_setup(ref_name, log_file, sizeof(log_file));
1437         if (result)
1438                 return result;
1439
1440         logfd = open(log_file, oflags);
1441         if (logfd < 0)
1442                 return 0;
1443         msglen = msg ? strlen(msg) : 0;
1444         committer = git_committer_info(0);
1445         maxlen = strlen(committer) + msglen + 100;
1446         logrec = xmalloc(maxlen);
1447         len = sprintf(logrec, "%s %s %s\n",
1448                       sha1_to_hex(old_sha1),
1449                       sha1_to_hex(new_sha1),
1450                       committer);
1451         if (msglen)
1452                 len += copy_msg(logrec + len - 1, msg) - 1;
1453         written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1454         free(logrec);
1455         if (close(logfd) != 0 || written != len)
1456                 return error("Unable to append to %s", log_file);
1457         return 0;
1458 }
1459
1460 static int is_branch(const char *refname)
1461 {
1462         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1463 }
1464
1465 int write_ref_sha1(struct ref_lock *lock,
1466         const unsigned char *sha1, const char *logmsg)
1467 {
1468         static char term = '\n';
1469         struct object *o;
1470
1471         if (!lock)
1472                 return -1;
1473         if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1474                 unlock_ref(lock);
1475                 return 0;
1476         }
1477         o = parse_object(sha1);
1478         if (!o) {
1479                 error("Trying to write ref %s with nonexistent object %s",
1480                         lock->ref_name, sha1_to_hex(sha1));
1481                 unlock_ref(lock);
1482                 return -1;
1483         }
1484         if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1485                 error("Trying to write non-commit object %s to branch %s",
1486                         sha1_to_hex(sha1), lock->ref_name);
1487                 unlock_ref(lock);
1488                 return -1;
1489         }
1490         if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1491             write_in_full(lock->lock_fd, &term, 1) != 1
1492                 || close_ref(lock) < 0) {
1493                 error("Couldn't write %s", lock->lk->filename);
1494                 unlock_ref(lock);
1495                 return -1;
1496         }
1497         invalidate_cached_refs();
1498         if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1499             (strcmp(lock->ref_name, lock->orig_ref_name) &&
1500              log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1501                 unlock_ref(lock);
1502                 return -1;
1503         }
1504         if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1505                 /*
1506                  * Special hack: If a branch is updated directly and HEAD
1507                  * points to it (may happen on the remote side of a push
1508                  * for example) then logically the HEAD reflog should be
1509                  * updated too.
1510                  * A generic solution implies reverse symref information,
1511                  * but finding all symrefs pointing to the given branch
1512                  * would be rather costly for this rare event (the direct
1513                  * update of a branch) to be worth it.  So let's cheat and
1514                  * check with HEAD only which should cover 99% of all usage
1515                  * scenarios (even 100% of the default ones).
1516                  */
1517                 unsigned char head_sha1[20];
1518                 int head_flag;
1519                 const char *head_ref;
1520                 head_ref = resolve_ref("HEAD", head_sha1, 1, &head_flag);
1521                 if (head_ref && (head_flag & REF_ISSYMREF) &&
1522                     !strcmp(head_ref, lock->ref_name))
1523                         log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1524         }
1525         if (commit_ref(lock)) {
1526                 error("Couldn't set %s", lock->ref_name);
1527                 unlock_ref(lock);
1528                 return -1;
1529         }
1530         unlock_ref(lock);
1531         return 0;
1532 }
1533
1534 int create_symref(const char *ref_target, const char *refs_heads_master,
1535                   const char *logmsg)
1536 {
1537         const char *lockpath;
1538         char ref[1000];
1539         int fd, len, written;
1540         char *git_HEAD = git_pathdup("%s", ref_target);
1541         unsigned char old_sha1[20], new_sha1[20];
1542
1543         if (logmsg && read_ref(ref_target, old_sha1))
1544                 hashclr(old_sha1);
1545
1546         if (safe_create_leading_directories(git_HEAD) < 0)
1547                 return error("unable to create directory for %s", git_HEAD);
1548
1549 #ifndef NO_SYMLINK_HEAD
1550         if (prefer_symlink_refs) {
1551                 unlink(git_HEAD);
1552                 if (!symlink(refs_heads_master, git_HEAD))
1553                         goto done;
1554                 fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1555         }
1556 #endif
1557
1558         len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1559         if (sizeof(ref) <= len) {
1560                 error("refname too long: %s", refs_heads_master);
1561                 goto error_free_return;
1562         }
1563         lockpath = mkpath("%s.lock", git_HEAD);
1564         fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1565         if (fd < 0) {
1566                 error("Unable to open %s for writing", lockpath);
1567                 goto error_free_return;
1568         }
1569         written = write_in_full(fd, ref, len);
1570         if (close(fd) != 0 || written != len) {
1571                 error("Unable to write to %s", lockpath);
1572                 goto error_unlink_return;
1573         }
1574         if (rename(lockpath, git_HEAD) < 0) {
1575                 error("Unable to create %s", git_HEAD);
1576                 goto error_unlink_return;
1577         }
1578         if (adjust_shared_perm(git_HEAD)) {
1579                 error("Unable to fix permissions on %s", lockpath);
1580         error_unlink_return:
1581                 unlink_or_warn(lockpath);
1582         error_free_return:
1583                 free(git_HEAD);
1584                 return -1;
1585         }
1586
1587 #ifndef NO_SYMLINK_HEAD
1588         done:
1589 #endif
1590         if (logmsg && !read_ref(refs_heads_master, new_sha1))
1591                 log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1592
1593         free(git_HEAD);
1594         return 0;
1595 }
1596
1597 static char *ref_msg(const char *line, const char *endp)
1598 {
1599         const char *ep;
1600         line += 82;
1601         ep = memchr(line, '\n', endp - line);
1602         if (!ep)
1603                 ep = endp;
1604         return xmemdupz(line, ep - line);
1605 }
1606
1607 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)
1608 {
1609         const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1610         char *tz_c;
1611         int logfd, tz, reccnt = 0;
1612         struct stat st;
1613         unsigned long date;
1614         unsigned char logged_sha1[20];
1615         void *log_mapped;
1616         size_t mapsz;
1617
1618         logfile = git_path("logs/%s", ref);
1619         logfd = open(logfile, O_RDONLY, 0);
1620         if (logfd < 0)
1621                 die_errno("Unable to read log '%s'", logfile);
1622         fstat(logfd, &st);
1623         if (!st.st_size)
1624                 die("Log %s is empty.", logfile);
1625         mapsz = xsize_t(st.st_size);
1626         log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1627         logdata = log_mapped;
1628         close(logfd);
1629
1630         lastrec = NULL;
1631         rec = logend = logdata + st.st_size;
1632         while (logdata < rec) {
1633                 reccnt++;
1634                 if (logdata < rec && *(rec-1) == '\n')
1635                         rec--;
1636                 lastgt = NULL;
1637                 while (logdata < rec && *(rec-1) != '\n') {
1638                         rec--;
1639                         if (*rec == '>')
1640                                 lastgt = rec;
1641                 }
1642                 if (!lastgt)
1643                         die("Log %s is corrupt.", logfile);
1644                 date = strtoul(lastgt + 1, &tz_c, 10);
1645                 if (date <= at_time || cnt == 0) {
1646                         tz = strtoul(tz_c, NULL, 10);
1647                         if (msg)
1648                                 *msg = ref_msg(rec, logend);
1649                         if (cutoff_time)
1650                                 *cutoff_time = date;
1651                         if (cutoff_tz)
1652                                 *cutoff_tz = tz;
1653                         if (cutoff_cnt)
1654                                 *cutoff_cnt = reccnt - 1;
1655                         if (lastrec) {
1656                                 if (get_sha1_hex(lastrec, logged_sha1))
1657                                         die("Log %s is corrupt.", logfile);
1658                                 if (get_sha1_hex(rec + 41, sha1))
1659                                         die("Log %s is corrupt.", logfile);
1660                                 if (hashcmp(logged_sha1, sha1)) {
1661                                         warning("Log %s has gap after %s.",
1662                                                 logfile, show_date(date, tz, DATE_RFC2822));
1663                                 }
1664                         }
1665                         else if (date == at_time) {
1666                                 if (get_sha1_hex(rec + 41, sha1))
1667                                         die("Log %s is corrupt.", logfile);
1668                         }
1669                         else {
1670                                 if (get_sha1_hex(rec + 41, logged_sha1))
1671                                         die("Log %s is corrupt.", logfile);
1672                                 if (hashcmp(logged_sha1, sha1)) {
1673                                         warning("Log %s unexpectedly ended on %s.",
1674                                                 logfile, show_date(date, tz, DATE_RFC2822));
1675                                 }
1676                         }
1677                         munmap(log_mapped, mapsz);
1678                         return 0;
1679                 }
1680                 lastrec = rec;
1681                 if (cnt > 0)
1682                         cnt--;
1683         }
1684
1685         rec = logdata;
1686         while (rec < logend && *rec != '>' && *rec != '\n')
1687                 rec++;
1688         if (rec == logend || *rec == '\n')
1689                 die("Log %s is corrupt.", logfile);
1690         date = strtoul(rec + 1, &tz_c, 10);
1691         tz = strtoul(tz_c, NULL, 10);
1692         if (get_sha1_hex(logdata, sha1))
1693                 die("Log %s is corrupt.", logfile);
1694         if (is_null_sha1(sha1)) {
1695                 if (get_sha1_hex(logdata + 41, sha1))
1696                         die("Log %s is corrupt.", logfile);
1697         }
1698         if (msg)
1699                 *msg = ref_msg(logdata, logend);
1700         munmap(log_mapped, mapsz);
1701
1702         if (cutoff_time)
1703                 *cutoff_time = date;
1704         if (cutoff_tz)
1705                 *cutoff_tz = tz;
1706         if (cutoff_cnt)
1707                 *cutoff_cnt = reccnt;
1708         return 1;
1709 }
1710
1711 int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long ofs, void *cb_data)
1712 {
1713         const char *logfile;
1714         FILE *logfp;
1715         struct strbuf sb = STRBUF_INIT;
1716         int ret = 0;
1717
1718         logfile = git_path("logs/%s", ref);
1719         logfp = fopen(logfile, "r");
1720         if (!logfp)
1721                 return -1;
1722
1723         if (ofs) {
1724                 struct stat statbuf;
1725                 if (fstat(fileno(logfp), &statbuf) ||
1726                     statbuf.st_size < ofs ||
1727                     fseek(logfp, -ofs, SEEK_END) ||
1728                     strbuf_getwholeline(&sb, logfp, '\n')) {
1729                         fclose(logfp);
1730                         strbuf_release(&sb);
1731                         return -1;
1732                 }
1733         }
1734
1735         while (!strbuf_getwholeline(&sb, logfp, '\n')) {
1736                 unsigned char osha1[20], nsha1[20];
1737                 char *email_end, *message;
1738                 unsigned long timestamp;
1739                 int tz;
1740
1741                 /* old SP new SP name <email> SP time TAB msg LF */
1742                 if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
1743                     get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
1744                     get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
1745                     !(email_end = strchr(sb.buf + 82, '>')) ||
1746                     email_end[1] != ' ' ||
1747                     !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1748                     !message || message[0] != ' ' ||
1749                     (message[1] != '+' && message[1] != '-') ||
1750                     !isdigit(message[2]) || !isdigit(message[3]) ||
1751                     !isdigit(message[4]) || !isdigit(message[5]))
1752                         continue; /* corrupt? */
1753                 email_end[1] = '\0';
1754                 tz = strtol(message + 1, NULL, 10);
1755                 if (message[6] != '\t')
1756                         message += 6;
1757                 else
1758                         message += 7;
1759                 ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
1760                          cb_data);
1761                 if (ret)
1762                         break;
1763         }
1764         fclose(logfp);
1765         strbuf_release(&sb);
1766         return ret;
1767 }
1768
1769 int for_each_reflog_ent(const char *ref, each_reflog_ent_fn fn, void *cb_data)
1770 {
1771         return for_each_recent_reflog_ent(ref, fn, 0, cb_data);
1772 }
1773
1774 static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1775 {
1776         DIR *dir = opendir(git_path("logs/%s", base));
1777         int retval = 0;
1778
1779         if (dir) {
1780                 struct dirent *de;
1781                 int baselen = strlen(base);
1782                 char *log = xmalloc(baselen + 257);
1783
1784                 memcpy(log, base, baselen);
1785                 if (baselen && base[baselen-1] != '/')
1786                         log[baselen++] = '/';
1787
1788                 while ((de = readdir(dir)) != NULL) {
1789                         struct stat st;
1790                         int namelen;
1791
1792                         if (de->d_name[0] == '.')
1793                                 continue;
1794                         namelen = strlen(de->d_name);
1795                         if (namelen > 255)
1796                                 continue;
1797                         if (has_extension(de->d_name, ".lock"))
1798                                 continue;
1799                         memcpy(log + baselen, de->d_name, namelen+1);
1800                         if (stat(git_path("logs/%s", log), &st) < 0)
1801                                 continue;
1802                         if (S_ISDIR(st.st_mode)) {
1803                                 retval = do_for_each_reflog(log, fn, cb_data);
1804                         } else {
1805                                 unsigned char sha1[20];
1806                                 if (!resolve_ref(log, sha1, 0, NULL))
1807                                         retval = error("bad ref for %s", log);
1808                                 else
1809                                         retval = fn(log, sha1, 0, cb_data);
1810                         }
1811                         if (retval)
1812                                 break;
1813                 }
1814                 free(log);
1815                 closedir(dir);
1816         }
1817         else if (*base)
1818                 return errno;
1819         return retval;
1820 }
1821
1822 int for_each_reflog(each_ref_fn fn, void *cb_data)
1823 {
1824         return do_for_each_reflog("", fn, cb_data);
1825 }
1826
1827 int update_ref(const char *action, const char *refname,
1828                 const unsigned char *sha1, const unsigned char *oldval,
1829                 int flags, enum action_on_err onerr)
1830 {
1831         static struct ref_lock *lock;
1832         lock = lock_any_ref_for_update(refname, oldval, flags);
1833         if (!lock) {
1834                 const char *str = "Cannot lock the ref '%s'.";
1835                 switch (onerr) {
1836                 case MSG_ON_ERR: error(str, refname); break;
1837                 case DIE_ON_ERR: die(str, refname); break;
1838                 case QUIET_ON_ERR: break;
1839                 }
1840                 return 1;
1841         }
1842         if (write_ref_sha1(lock, sha1, action) < 0) {
1843                 const char *str = "Cannot update the ref '%s'.";
1844                 switch (onerr) {
1845                 case MSG_ON_ERR: error(str, refname); break;
1846                 case DIE_ON_ERR: die(str, refname); break;
1847                 case QUIET_ON_ERR: break;
1848                 }
1849                 return 1;
1850         }
1851         return 0;
1852 }
1853
1854 int ref_exists(char *refname)
1855 {
1856         unsigned char sha1[20];
1857         return !!resolve_ref(refname, sha1, 1, NULL);
1858 }
1859
1860 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1861 {
1862         for ( ; list; list = list->next)
1863                 if (!strcmp(list->name, name))
1864                         return (struct ref *)list;
1865         return NULL;
1866 }
1867
1868 /*
1869  * generate a format suitable for scanf from a ref_rev_parse_rules
1870  * rule, that is replace the "%.*s" spec with a "%s" spec
1871  */
1872 static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
1873 {
1874         char *spec;
1875
1876         spec = strstr(rule, "%.*s");
1877         if (!spec || strstr(spec + 4, "%.*s"))
1878                 die("invalid rule in ref_rev_parse_rules: %s", rule);
1879
1880         /* copy all until spec */
1881         strncpy(scanf_fmt, rule, spec - rule);
1882         scanf_fmt[spec - rule] = '\0';
1883         /* copy new spec */
1884         strcat(scanf_fmt, "%s");
1885         /* copy remaining rule */
1886         strcat(scanf_fmt, spec + 4);
1887
1888         return;
1889 }
1890
1891 char *shorten_unambiguous_ref(const char *ref, int strict)
1892 {
1893         int i;
1894         static char **scanf_fmts;
1895         static int nr_rules;
1896         char *short_name;
1897
1898         /* pre generate scanf formats from ref_rev_parse_rules[] */
1899         if (!nr_rules) {
1900                 size_t total_len = 0;
1901
1902                 /* the rule list is NULL terminated, count them first */
1903                 for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
1904                         /* no +1 because strlen("%s") < strlen("%.*s") */
1905                         total_len += strlen(ref_rev_parse_rules[nr_rules]);
1906
1907                 scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
1908
1909                 total_len = 0;
1910                 for (i = 0; i < nr_rules; i++) {
1911                         scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
1912                                         + total_len;
1913                         gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
1914                         total_len += strlen(ref_rev_parse_rules[i]);
1915                 }
1916         }
1917
1918         /* bail out if there are no rules */
1919         if (!nr_rules)
1920                 return xstrdup(ref);
1921
1922         /* buffer for scanf result, at most ref must fit */
1923         short_name = xstrdup(ref);
1924
1925         /* skip first rule, it will always match */
1926         for (i = nr_rules - 1; i > 0 ; --i) {
1927                 int j;
1928                 int rules_to_fail = i;
1929                 int short_name_len;
1930
1931                 if (1 != sscanf(ref, scanf_fmts[i], short_name))
1932                         continue;
1933
1934                 short_name_len = strlen(short_name);
1935
1936                 /*
1937                  * in strict mode, all (except the matched one) rules
1938                  * must fail to resolve to a valid non-ambiguous ref
1939                  */
1940                 if (strict)
1941                         rules_to_fail = nr_rules;
1942
1943                 /*
1944                  * check if the short name resolves to a valid ref,
1945                  * but use only rules prior to the matched one
1946                  */
1947                 for (j = 0; j < rules_to_fail; j++) {
1948                         const char *rule = ref_rev_parse_rules[j];
1949                         unsigned char short_objectname[20];
1950                         char refname[PATH_MAX];
1951
1952                         /* skip matched rule */
1953                         if (i == j)
1954                                 continue;
1955
1956                         /*
1957                          * the short name is ambiguous, if it resolves
1958                          * (with this previous rule) to a valid ref
1959                          * read_ref() returns 0 on success
1960                          */
1961                         mksnpath(refname, sizeof(refname),
1962                                  rule, short_name_len, short_name);
1963                         if (!read_ref(refname, short_objectname))
1964                                 break;
1965                 }
1966
1967                 /*
1968                  * short name is non-ambiguous if all previous rules
1969                  * haven't resolved to a valid ref
1970                  */
1971                 if (j == rules_to_fail)
1972                         return short_name;
1973         }
1974
1975         free(short_name);
1976         return xstrdup(ref);
1977 }