Merge branch 'mg/timestamp-t-fix'
[git] / builtin / reflog.c
1 #include "builtin.h"
2 #include "config.h"
3 #include "lockfile.h"
4 #include "commit.h"
5 #include "refs.h"
6 #include "dir.h"
7 #include "tree-walk.h"
8 #include "diff.h"
9 #include "revision.h"
10 #include "reachable.h"
11
12 /* NEEDSWORK: switch to using parse_options */
13 static const char reflog_expire_usage[] =
14 "git reflog expire [--expire=<time>] [--expire-unreachable=<time>] [--rewrite] [--updateref] [--stale-fix] [--dry-run | -n] [--verbose] [--all] <refs>...";
15 static const char reflog_delete_usage[] =
16 "git reflog delete [--rewrite] [--updateref] [--dry-run | -n] [--verbose] <refs>...";
17 static const char reflog_exists_usage[] =
18 "git reflog exists <ref>";
19
20 static timestamp_t default_reflog_expire;
21 static timestamp_t default_reflog_expire_unreachable;
22
23 struct cmd_reflog_expire_cb {
24         struct rev_info revs;
25         int stalefix;
26         timestamp_t expire_total;
27         timestamp_t expire_unreachable;
28         int recno;
29 };
30
31 struct expire_reflog_policy_cb {
32         enum {
33                 UE_NORMAL,
34                 UE_ALWAYS,
35                 UE_HEAD
36         } unreachable_expire_kind;
37         struct commit_list *mark_list;
38         unsigned long mark_limit;
39         struct cmd_reflog_expire_cb cmd;
40         struct commit *tip_commit;
41         struct commit_list *tips;
42 };
43
44 struct collected_reflog {
45         unsigned char sha1[20];
46         char reflog[FLEX_ARRAY];
47 };
48
49 struct collect_reflog_cb {
50         struct collected_reflog **e;
51         int alloc;
52         int nr;
53 };
54
55 #define INCOMPLETE      (1u<<10)
56 #define STUDYING        (1u<<11)
57 #define REACHABLE       (1u<<12)
58
59 static int tree_is_complete(const struct object_id *oid)
60 {
61         struct tree_desc desc;
62         struct name_entry entry;
63         int complete;
64         struct tree *tree;
65
66         tree = lookup_tree(oid);
67         if (!tree)
68                 return 0;
69         if (tree->object.flags & SEEN)
70                 return 1;
71         if (tree->object.flags & INCOMPLETE)
72                 return 0;
73
74         if (!tree->buffer) {
75                 enum object_type type;
76                 unsigned long size;
77                 void *data = read_sha1_file(oid->hash, &type, &size);
78                 if (!data) {
79                         tree->object.flags |= INCOMPLETE;
80                         return 0;
81                 }
82                 tree->buffer = data;
83                 tree->size = size;
84         }
85         init_tree_desc(&desc, tree->buffer, tree->size);
86         complete = 1;
87         while (tree_entry(&desc, &entry)) {
88                 if (!has_sha1_file(entry.oid->hash) ||
89                     (S_ISDIR(entry.mode) && !tree_is_complete(entry.oid))) {
90                         tree->object.flags |= INCOMPLETE;
91                         complete = 0;
92                 }
93         }
94         free_tree_buffer(tree);
95
96         if (complete)
97                 tree->object.flags |= SEEN;
98         return complete;
99 }
100
101 static int commit_is_complete(struct commit *commit)
102 {
103         struct object_array study;
104         struct object_array found;
105         int is_incomplete = 0;
106         int i;
107
108         /* early return */
109         if (commit->object.flags & SEEN)
110                 return 1;
111         if (commit->object.flags & INCOMPLETE)
112                 return 0;
113         /*
114          * Find all commits that are reachable and are not marked as
115          * SEEN.  Then make sure the trees and blobs contained are
116          * complete.  After that, mark these commits also as SEEN.
117          * If some of the objects that are needed to complete this
118          * commit are missing, mark this commit as INCOMPLETE.
119          */
120         memset(&study, 0, sizeof(study));
121         memset(&found, 0, sizeof(found));
122         add_object_array(&commit->object, NULL, &study);
123         add_object_array(&commit->object, NULL, &found);
124         commit->object.flags |= STUDYING;
125         while (study.nr) {
126                 struct commit *c;
127                 struct commit_list *parent;
128
129                 c = (struct commit *)study.objects[--study.nr].item;
130                 if (!c->object.parsed && !parse_object(&c->object.oid))
131                         c->object.flags |= INCOMPLETE;
132
133                 if (c->object.flags & INCOMPLETE) {
134                         is_incomplete = 1;
135                         break;
136                 }
137                 else if (c->object.flags & SEEN)
138                         continue;
139                 for (parent = c->parents; parent; parent = parent->next) {
140                         struct commit *p = parent->item;
141                         if (p->object.flags & STUDYING)
142                                 continue;
143                         p->object.flags |= STUDYING;
144                         add_object_array(&p->object, NULL, &study);
145                         add_object_array(&p->object, NULL, &found);
146                 }
147         }
148         if (!is_incomplete) {
149                 /*
150                  * make sure all commits in "found" array have all the
151                  * necessary objects.
152                  */
153                 for (i = 0; i < found.nr; i++) {
154                         struct commit *c =
155                                 (struct commit *)found.objects[i].item;
156                         if (!tree_is_complete(&c->tree->object.oid)) {
157                                 is_incomplete = 1;
158                                 c->object.flags |= INCOMPLETE;
159                         }
160                 }
161                 if (!is_incomplete) {
162                         /* mark all found commits as complete, iow SEEN */
163                         for (i = 0; i < found.nr; i++)
164                                 found.objects[i].item->flags |= SEEN;
165                 }
166         }
167         /* clear flags from the objects we traversed */
168         for (i = 0; i < found.nr; i++)
169                 found.objects[i].item->flags &= ~STUDYING;
170         if (is_incomplete)
171                 commit->object.flags |= INCOMPLETE;
172         else {
173                 /*
174                  * If we come here, we have (1) traversed the ancestry chain
175                  * from the "commit" until we reach SEEN commits (which are
176                  * known to be complete), and (2) made sure that the commits
177                  * encountered during the above traversal refer to trees that
178                  * are complete.  Which means that we know *all* the commits
179                  * we have seen during this process are complete.
180                  */
181                 for (i = 0; i < found.nr; i++)
182                         found.objects[i].item->flags |= SEEN;
183         }
184         /* free object arrays */
185         free(study.objects);
186         free(found.objects);
187         return !is_incomplete;
188 }
189
190 static int keep_entry(struct commit **it, struct object_id *oid)
191 {
192         struct commit *commit;
193
194         if (is_null_oid(oid))
195                 return 1;
196         commit = lookup_commit_reference_gently(oid, 1);
197         if (!commit)
198                 return 0;
199
200         /*
201          * Make sure everything in this commit exists.
202          *
203          * We have walked all the objects reachable from the refs
204          * and cache earlier.  The commits reachable by this commit
205          * must meet SEEN commits -- and then we should mark them as
206          * SEEN as well.
207          */
208         if (!commit_is_complete(commit))
209                 return 0;
210         *it = commit;
211         return 1;
212 }
213
214 /*
215  * Starting from commits in the cb->mark_list, mark commits that are
216  * reachable from them.  Stop the traversal at commits older than
217  * the expire_limit and queue them back, so that the caller can call
218  * us again to restart the traversal with longer expire_limit.
219  */
220 static void mark_reachable(struct expire_reflog_policy_cb *cb)
221 {
222         struct commit_list *pending;
223         timestamp_t expire_limit = cb->mark_limit;
224         struct commit_list *leftover = NULL;
225
226         for (pending = cb->mark_list; pending; pending = pending->next)
227                 pending->item->object.flags &= ~REACHABLE;
228
229         pending = cb->mark_list;
230         while (pending) {
231                 struct commit_list *parent;
232                 struct commit *commit = pop_commit(&pending);
233                 if (commit->object.flags & REACHABLE)
234                         continue;
235                 if (parse_commit(commit))
236                         continue;
237                 commit->object.flags |= REACHABLE;
238                 if (commit->date < expire_limit) {
239                         commit_list_insert(commit, &leftover);
240                         continue;
241                 }
242                 commit->object.flags |= REACHABLE;
243                 parent = commit->parents;
244                 while (parent) {
245                         commit = parent->item;
246                         parent = parent->next;
247                         if (commit->object.flags & REACHABLE)
248                                 continue;
249                         commit_list_insert(commit, &pending);
250                 }
251         }
252         cb->mark_list = leftover;
253 }
254
255 static int unreachable(struct expire_reflog_policy_cb *cb, struct commit *commit, struct object_id *oid)
256 {
257         /*
258          * We may or may not have the commit yet - if not, look it
259          * up using the supplied sha1.
260          */
261         if (!commit) {
262                 if (is_null_oid(oid))
263                         return 0;
264
265                 commit = lookup_commit_reference_gently(oid, 1);
266
267                 /* Not a commit -- keep it */
268                 if (!commit)
269                         return 0;
270         }
271
272         /* Reachable from the current ref?  Don't prune. */
273         if (commit->object.flags & REACHABLE)
274                 return 0;
275
276         if (cb->mark_list && cb->mark_limit) {
277                 cb->mark_limit = 0; /* dig down to the root */
278                 mark_reachable(cb);
279         }
280
281         return !(commit->object.flags & REACHABLE);
282 }
283
284 /*
285  * Return true iff the specified reflog entry should be expired.
286  */
287 static int should_expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
288                                     const char *email, timestamp_t timestamp, int tz,
289                                     const char *message, void *cb_data)
290 {
291         struct expire_reflog_policy_cb *cb = cb_data;
292         struct commit *old, *new;
293
294         if (timestamp < cb->cmd.expire_total)
295                 return 1;
296
297         old = new = NULL;
298         if (cb->cmd.stalefix &&
299             (!keep_entry(&old, ooid) || !keep_entry(&new, noid)))
300                 return 1;
301
302         if (timestamp < cb->cmd.expire_unreachable) {
303                 if (cb->unreachable_expire_kind == UE_ALWAYS)
304                         return 1;
305                 if (unreachable(cb, old, ooid) || unreachable(cb, new, noid))
306                         return 1;
307         }
308
309         if (cb->cmd.recno && --(cb->cmd.recno) == 0)
310                 return 1;
311
312         return 0;
313 }
314
315 static int push_tip_to_list(const char *refname, const struct object_id *oid,
316                             int flags, void *cb_data)
317 {
318         struct commit_list **list = cb_data;
319         struct commit *tip_commit;
320         if (flags & REF_ISSYMREF)
321                 return 0;
322         tip_commit = lookup_commit_reference_gently(oid, 1);
323         if (!tip_commit)
324                 return 0;
325         commit_list_insert(tip_commit, list);
326         return 0;
327 }
328
329 static void reflog_expiry_prepare(const char *refname,
330                                   const struct object_id *oid,
331                                   void *cb_data)
332 {
333         struct expire_reflog_policy_cb *cb = cb_data;
334
335         if (!cb->cmd.expire_unreachable || !strcmp(refname, "HEAD")) {
336                 cb->tip_commit = NULL;
337                 cb->unreachable_expire_kind = UE_HEAD;
338         } else {
339                 cb->tip_commit = lookup_commit_reference_gently(oid, 1);
340                 if (!cb->tip_commit)
341                         cb->unreachable_expire_kind = UE_ALWAYS;
342                 else
343                         cb->unreachable_expire_kind = UE_NORMAL;
344         }
345
346         if (cb->cmd.expire_unreachable <= cb->cmd.expire_total)
347                 cb->unreachable_expire_kind = UE_ALWAYS;
348
349         cb->mark_list = NULL;
350         cb->tips = NULL;
351         if (cb->unreachable_expire_kind != UE_ALWAYS) {
352                 if (cb->unreachable_expire_kind == UE_HEAD) {
353                         struct commit_list *elem;
354
355                         for_each_ref(push_tip_to_list, &cb->tips);
356                         for (elem = cb->tips; elem; elem = elem->next)
357                                 commit_list_insert(elem->item, &cb->mark_list);
358                 } else {
359                         commit_list_insert(cb->tip_commit, &cb->mark_list);
360                 }
361                 cb->mark_limit = cb->cmd.expire_total;
362                 mark_reachable(cb);
363         }
364 }
365
366 static void reflog_expiry_cleanup(void *cb_data)
367 {
368         struct expire_reflog_policy_cb *cb = cb_data;
369
370         if (cb->unreachable_expire_kind != UE_ALWAYS) {
371                 if (cb->unreachable_expire_kind == UE_HEAD) {
372                         struct commit_list *elem;
373                         for (elem = cb->tips; elem; elem = elem->next)
374                                 clear_commit_marks(elem->item, REACHABLE);
375                         free_commit_list(cb->tips);
376                 } else {
377                         clear_commit_marks(cb->tip_commit, REACHABLE);
378                 }
379         }
380 }
381
382 static int collect_reflog(const char *ref, const struct object_id *oid, int unused, void *cb_data)
383 {
384         struct collected_reflog *e;
385         struct collect_reflog_cb *cb = cb_data;
386
387         FLEX_ALLOC_STR(e, reflog, ref);
388         hashcpy(e->sha1, oid->hash);
389         ALLOC_GROW(cb->e, cb->nr + 1, cb->alloc);
390         cb->e[cb->nr++] = e;
391         return 0;
392 }
393
394 static struct reflog_expire_cfg {
395         struct reflog_expire_cfg *next;
396         timestamp_t expire_total;
397         timestamp_t expire_unreachable;
398         char pattern[FLEX_ARRAY];
399 } *reflog_expire_cfg, **reflog_expire_cfg_tail;
400
401 static struct reflog_expire_cfg *find_cfg_ent(const char *pattern, size_t len)
402 {
403         struct reflog_expire_cfg *ent;
404
405         if (!reflog_expire_cfg_tail)
406                 reflog_expire_cfg_tail = &reflog_expire_cfg;
407
408         for (ent = reflog_expire_cfg; ent; ent = ent->next)
409                 if (!strncmp(ent->pattern, pattern, len) &&
410                     ent->pattern[len] == '\0')
411                         return ent;
412
413         FLEX_ALLOC_MEM(ent, pattern, pattern, len);
414         *reflog_expire_cfg_tail = ent;
415         reflog_expire_cfg_tail = &(ent->next);
416         return ent;
417 }
418
419 static int parse_expire_cfg_value(const char *var, const char *value, timestamp_t *expire)
420 {
421         if (!value)
422                 return config_error_nonbool(var);
423         if (parse_expiry_date(value, expire))
424                 return error(_("'%s' for '%s' is not a valid timestamp"),
425                              value, var);
426         return 0;
427 }
428
429 /* expiry timer slot */
430 #define EXPIRE_TOTAL   01
431 #define EXPIRE_UNREACH 02
432
433 static int reflog_expire_config(const char *var, const char *value, void *cb)
434 {
435         const char *pattern, *key;
436         int pattern_len;
437         timestamp_t expire;
438         int slot;
439         struct reflog_expire_cfg *ent;
440
441         if (parse_config_key(var, "gc", &pattern, &pattern_len, &key) < 0)
442                 return git_default_config(var, value, cb);
443
444         if (!strcmp(key, "reflogexpire")) {
445                 slot = EXPIRE_TOTAL;
446                 if (parse_expire_cfg_value(var, value, &expire))
447                         return -1;
448         } else if (!strcmp(key, "reflogexpireunreachable")) {
449                 slot = EXPIRE_UNREACH;
450                 if (parse_expire_cfg_value(var, value, &expire))
451                         return -1;
452         } else
453                 return git_default_config(var, value, cb);
454
455         if (!pattern) {
456                 switch (slot) {
457                 case EXPIRE_TOTAL:
458                         default_reflog_expire = expire;
459                         break;
460                 case EXPIRE_UNREACH:
461                         default_reflog_expire_unreachable = expire;
462                         break;
463                 }
464                 return 0;
465         }
466
467         ent = find_cfg_ent(pattern, pattern_len);
468         if (!ent)
469                 return -1;
470         switch (slot) {
471         case EXPIRE_TOTAL:
472                 ent->expire_total = expire;
473                 break;
474         case EXPIRE_UNREACH:
475                 ent->expire_unreachable = expire;
476                 break;
477         }
478         return 0;
479 }
480
481 static void set_reflog_expiry_param(struct cmd_reflog_expire_cb *cb, int slot, const char *ref)
482 {
483         struct reflog_expire_cfg *ent;
484
485         if (slot == (EXPIRE_TOTAL|EXPIRE_UNREACH))
486                 return; /* both given explicitly -- nothing to tweak */
487
488         for (ent = reflog_expire_cfg; ent; ent = ent->next) {
489                 if (!wildmatch(ent->pattern, ref, 0)) {
490                         if (!(slot & EXPIRE_TOTAL))
491                                 cb->expire_total = ent->expire_total;
492                         if (!(slot & EXPIRE_UNREACH))
493                                 cb->expire_unreachable = ent->expire_unreachable;
494                         return;
495                 }
496         }
497
498         /*
499          * If unconfigured, make stash never expire
500          */
501         if (!strcmp(ref, "refs/stash")) {
502                 if (!(slot & EXPIRE_TOTAL))
503                         cb->expire_total = 0;
504                 if (!(slot & EXPIRE_UNREACH))
505                         cb->expire_unreachable = 0;
506                 return;
507         }
508
509         /* Nothing matched -- use the default value */
510         if (!(slot & EXPIRE_TOTAL))
511                 cb->expire_total = default_reflog_expire;
512         if (!(slot & EXPIRE_UNREACH))
513                 cb->expire_unreachable = default_reflog_expire_unreachable;
514 }
515
516 static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
517 {
518         struct expire_reflog_policy_cb cb;
519         timestamp_t now = time(NULL);
520         int i, status, do_all;
521         int explicit_expiry = 0;
522         unsigned int flags = 0;
523
524         default_reflog_expire_unreachable = now - 30 * 24 * 3600;
525         default_reflog_expire = now - 90 * 24 * 3600;
526         git_config(reflog_expire_config, NULL);
527
528         save_commit_buffer = 0;
529         do_all = status = 0;
530         memset(&cb, 0, sizeof(cb));
531
532         cb.cmd.expire_total = default_reflog_expire;
533         cb.cmd.expire_unreachable = default_reflog_expire_unreachable;
534
535         for (i = 1; i < argc; i++) {
536                 const char *arg = argv[i];
537                 if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
538                         flags |= EXPIRE_REFLOGS_DRY_RUN;
539                 else if (starts_with(arg, "--expire=")) {
540                         if (parse_expiry_date(arg + 9, &cb.cmd.expire_total))
541                                 die(_("'%s' is not a valid timestamp"), arg);
542                         explicit_expiry |= EXPIRE_TOTAL;
543                 }
544                 else if (starts_with(arg, "--expire-unreachable=")) {
545                         if (parse_expiry_date(arg + 21, &cb.cmd.expire_unreachable))
546                                 die(_("'%s' is not a valid timestamp"), arg);
547                         explicit_expiry |= EXPIRE_UNREACH;
548                 }
549                 else if (!strcmp(arg, "--stale-fix"))
550                         cb.cmd.stalefix = 1;
551                 else if (!strcmp(arg, "--rewrite"))
552                         flags |= EXPIRE_REFLOGS_REWRITE;
553                 else if (!strcmp(arg, "--updateref"))
554                         flags |= EXPIRE_REFLOGS_UPDATE_REF;
555                 else if (!strcmp(arg, "--all"))
556                         do_all = 1;
557                 else if (!strcmp(arg, "--verbose"))
558                         flags |= EXPIRE_REFLOGS_VERBOSE;
559                 else if (!strcmp(arg, "--")) {
560                         i++;
561                         break;
562                 }
563                 else if (arg[0] == '-')
564                         usage(reflog_expire_usage);
565                 else
566                         break;
567         }
568
569         /*
570          * We can trust the commits and objects reachable from refs
571          * even in older repository.  We cannot trust what's reachable
572          * from reflog if the repository was pruned with older git.
573          */
574         if (cb.cmd.stalefix) {
575                 init_revisions(&cb.cmd.revs, prefix);
576                 if (flags & EXPIRE_REFLOGS_VERBOSE)
577                         printf("Marking reachable objects...");
578                 mark_reachable_objects(&cb.cmd.revs, 0, 0, NULL);
579                 if (flags & EXPIRE_REFLOGS_VERBOSE)
580                         putchar('\n');
581         }
582
583         if (do_all) {
584                 struct collect_reflog_cb collected;
585                 int i;
586
587                 memset(&collected, 0, sizeof(collected));
588                 for_each_reflog(collect_reflog, &collected);
589                 for (i = 0; i < collected.nr; i++) {
590                         struct collected_reflog *e = collected.e[i];
591                         set_reflog_expiry_param(&cb.cmd, explicit_expiry, e->reflog);
592                         status |= reflog_expire(e->reflog, e->sha1, flags,
593                                                 reflog_expiry_prepare,
594                                                 should_expire_reflog_ent,
595                                                 reflog_expiry_cleanup,
596                                                 &cb);
597                         free(e);
598                 }
599                 free(collected.e);
600         }
601
602         for (; i < argc; i++) {
603                 char *ref;
604                 unsigned char sha1[20];
605                 if (!dwim_log(argv[i], strlen(argv[i]), sha1, &ref)) {
606                         status |= error("%s points nowhere!", argv[i]);
607                         continue;
608                 }
609                 set_reflog_expiry_param(&cb.cmd, explicit_expiry, ref);
610                 status |= reflog_expire(ref, sha1, flags,
611                                         reflog_expiry_prepare,
612                                         should_expire_reflog_ent,
613                                         reflog_expiry_cleanup,
614                                         &cb);
615         }
616         return status;
617 }
618
619 static int count_reflog_ent(struct object_id *ooid, struct object_id *noid,
620                 const char *email, timestamp_t timestamp, int tz,
621                 const char *message, void *cb_data)
622 {
623         struct expire_reflog_policy_cb *cb = cb_data;
624         if (!cb->cmd.expire_total || timestamp < cb->cmd.expire_total)
625                 cb->cmd.recno++;
626         return 0;
627 }
628
629 static int cmd_reflog_delete(int argc, const char **argv, const char *prefix)
630 {
631         struct expire_reflog_policy_cb cb;
632         int i, status = 0;
633         unsigned int flags = 0;
634
635         memset(&cb, 0, sizeof(cb));
636
637         for (i = 1; i < argc; i++) {
638                 const char *arg = argv[i];
639                 if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
640                         flags |= EXPIRE_REFLOGS_DRY_RUN;
641                 else if (!strcmp(arg, "--rewrite"))
642                         flags |= EXPIRE_REFLOGS_REWRITE;
643                 else if (!strcmp(arg, "--updateref"))
644                         flags |= EXPIRE_REFLOGS_UPDATE_REF;
645                 else if (!strcmp(arg, "--verbose"))
646                         flags |= EXPIRE_REFLOGS_VERBOSE;
647                 else if (!strcmp(arg, "--")) {
648                         i++;
649                         break;
650                 }
651                 else if (arg[0] == '-')
652                         usage(reflog_delete_usage);
653                 else
654                         break;
655         }
656
657         if (argc - i < 1)
658                 return error("Nothing to delete?");
659
660         for ( ; i < argc; i++) {
661                 const char *spec = strstr(argv[i], "@{");
662                 unsigned char sha1[20];
663                 char *ep, *ref;
664                 int recno;
665
666                 if (!spec) {
667                         status |= error("Not a reflog: %s", argv[i]);
668                         continue;
669                 }
670
671                 if (!dwim_log(argv[i], spec - argv[i], sha1, &ref)) {
672                         status |= error("no reflog for '%s'", argv[i]);
673                         continue;
674                 }
675
676                 recno = strtoul(spec + 2, &ep, 10);
677                 if (*ep == '}') {
678                         cb.cmd.recno = -recno;
679                         for_each_reflog_ent(ref, count_reflog_ent, &cb);
680                 } else {
681                         cb.cmd.expire_total = approxidate(spec + 2);
682                         for_each_reflog_ent(ref, count_reflog_ent, &cb);
683                         cb.cmd.expire_total = 0;
684                 }
685
686                 status |= reflog_expire(ref, sha1, flags,
687                                         reflog_expiry_prepare,
688                                         should_expire_reflog_ent,
689                                         reflog_expiry_cleanup,
690                                         &cb);
691                 free(ref);
692         }
693         return status;
694 }
695
696 static int cmd_reflog_exists(int argc, const char **argv, const char *prefix)
697 {
698         int i, start = 0;
699
700         for (i = 1; i < argc; i++) {
701                 const char *arg = argv[i];
702                 if (!strcmp(arg, "--")) {
703                         i++;
704                         break;
705                 }
706                 else if (arg[0] == '-')
707                         usage(reflog_exists_usage);
708                 else
709                         break;
710         }
711
712         start = i;
713
714         if (argc - start != 1)
715                 usage(reflog_exists_usage);
716
717         if (check_refname_format(argv[start], REFNAME_ALLOW_ONELEVEL))
718                 die("invalid ref format: %s", argv[start]);
719         return !reflog_exists(argv[start]);
720 }
721
722 /*
723  * main "reflog"
724  */
725
726 static const char reflog_usage[] =
727 "git reflog [ show | expire | delete | exists ]";
728
729 int cmd_reflog(int argc, const char **argv, const char *prefix)
730 {
731         if (argc > 1 && !strcmp(argv[1], "-h"))
732                 usage(reflog_usage);
733
734         /* With no command, we default to showing it. */
735         if (argc < 2 || *argv[1] == '-')
736                 return cmd_log_reflog(argc, argv, prefix);
737
738         if (!strcmp(argv[1], "show"))
739                 return cmd_log_reflog(argc - 1, argv + 1, prefix);
740
741         if (!strcmp(argv[1], "expire"))
742                 return cmd_reflog_expire(argc - 1, argv + 1, prefix);
743
744         if (!strcmp(argv[1], "delete"))
745                 return cmd_reflog_delete(argc - 1, argv + 1, prefix);
746
747         if (!strcmp(argv[1], "exists"))
748                 return cmd_reflog_exists(argc - 1, argv + 1, prefix);
749
750         return cmd_log_reflog(argc, argv, prefix);
751 }