Merge branch 'sg/fix-versioncmp-with-common-suffix'
[git] / builtin / reflog.c
1 #include "builtin.h"
2 #include "lockfile.h"
3 #include "commit.h"
4 #include "refs.h"
5 #include "dir.h"
6 #include "tree-walk.h"
7 #include "diff.h"
8 #include "revision.h"
9 #include "reachable.h"
10
11 /* NEEDSWORK: switch to using parse_options */
12 static const char reflog_expire_usage[] =
13 "git reflog expire [--expire=<time>] [--expire-unreachable=<time>] [--rewrite] [--updateref] [--stale-fix] [--dry-run | -n] [--verbose] [--all] <refs>...";
14 static const char reflog_delete_usage[] =
15 "git reflog delete [--rewrite] [--updateref] [--dry-run | -n] [--verbose] <refs>...";
16 static const char reflog_exists_usage[] =
17 "git reflog exists <ref>";
18
19 static unsigned long default_reflog_expire;
20 static unsigned long default_reflog_expire_unreachable;
21
22 struct cmd_reflog_expire_cb {
23         struct rev_info revs;
24         int stalefix;
25         unsigned long expire_total;
26         unsigned long expire_unreachable;
27         int recno;
28 };
29
30 struct expire_reflog_policy_cb {
31         enum {
32                 UE_NORMAL,
33                 UE_ALWAYS,
34                 UE_HEAD
35         } unreachable_expire_kind;
36         struct commit_list *mark_list;
37         unsigned long mark_limit;
38         struct cmd_reflog_expire_cb cmd;
39         struct commit *tip_commit;
40         struct commit_list *tips;
41 };
42
43 struct collected_reflog {
44         unsigned char sha1[20];
45         char reflog[FLEX_ARRAY];
46 };
47
48 struct collect_reflog_cb {
49         struct collected_reflog **e;
50         int alloc;
51         int nr;
52 };
53
54 #define INCOMPLETE      (1u<<10)
55 #define STUDYING        (1u<<11)
56 #define REACHABLE       (1u<<12)
57
58 static int tree_is_complete(const unsigned char *sha1)
59 {
60         struct tree_desc desc;
61         struct name_entry entry;
62         int complete;
63         struct tree *tree;
64
65         tree = lookup_tree(sha1);
66         if (!tree)
67                 return 0;
68         if (tree->object.flags & SEEN)
69                 return 1;
70         if (tree->object.flags & INCOMPLETE)
71                 return 0;
72
73         if (!tree->buffer) {
74                 enum object_type type;
75                 unsigned long size;
76                 void *data = read_sha1_file(sha1, &type, &size);
77                 if (!data) {
78                         tree->object.flags |= INCOMPLETE;
79                         return 0;
80                 }
81                 tree->buffer = data;
82                 tree->size = size;
83         }
84         init_tree_desc(&desc, tree->buffer, tree->size);
85         complete = 1;
86         while (tree_entry(&desc, &entry)) {
87                 if (!has_sha1_file(entry.oid->hash) ||
88                     (S_ISDIR(entry.mode) && !tree_is_complete(entry.oid->hash))) {
89                         tree->object.flags |= INCOMPLETE;
90                         complete = 0;
91                 }
92         }
93         free_tree_buffer(tree);
94
95         if (complete)
96                 tree->object.flags |= SEEN;
97         return complete;
98 }
99
100 static int commit_is_complete(struct commit *commit)
101 {
102         struct object_array study;
103         struct object_array found;
104         int is_incomplete = 0;
105         int i;
106
107         /* early return */
108         if (commit->object.flags & SEEN)
109                 return 1;
110         if (commit->object.flags & INCOMPLETE)
111                 return 0;
112         /*
113          * Find all commits that are reachable and are not marked as
114          * SEEN.  Then make sure the trees and blobs contained are
115          * complete.  After that, mark these commits also as SEEN.
116          * If some of the objects that are needed to complete this
117          * commit are missing, mark this commit as INCOMPLETE.
118          */
119         memset(&study, 0, sizeof(study));
120         memset(&found, 0, sizeof(found));
121         add_object_array(&commit->object, NULL, &study);
122         add_object_array(&commit->object, NULL, &found);
123         commit->object.flags |= STUDYING;
124         while (study.nr) {
125                 struct commit *c;
126                 struct commit_list *parent;
127
128                 c = (struct commit *)study.objects[--study.nr].item;
129                 if (!c->object.parsed && !parse_object(c->object.oid.hash))
130                         c->object.flags |= INCOMPLETE;
131
132                 if (c->object.flags & INCOMPLETE) {
133                         is_incomplete = 1;
134                         break;
135                 }
136                 else if (c->object.flags & SEEN)
137                         continue;
138                 for (parent = c->parents; parent; parent = parent->next) {
139                         struct commit *p = parent->item;
140                         if (p->object.flags & STUDYING)
141                                 continue;
142                         p->object.flags |= STUDYING;
143                         add_object_array(&p->object, NULL, &study);
144                         add_object_array(&p->object, NULL, &found);
145                 }
146         }
147         if (!is_incomplete) {
148                 /*
149                  * make sure all commits in "found" array have all the
150                  * necessary objects.
151                  */
152                 for (i = 0; i < found.nr; i++) {
153                         struct commit *c =
154                                 (struct commit *)found.objects[i].item;
155                         if (!tree_is_complete(c->tree->object.oid.hash)) {
156                                 is_incomplete = 1;
157                                 c->object.flags |= INCOMPLETE;
158                         }
159                 }
160                 if (!is_incomplete) {
161                         /* mark all found commits as complete, iow SEEN */
162                         for (i = 0; i < found.nr; i++)
163                                 found.objects[i].item->flags |= SEEN;
164                 }
165         }
166         /* clear flags from the objects we traversed */
167         for (i = 0; i < found.nr; i++)
168                 found.objects[i].item->flags &= ~STUDYING;
169         if (is_incomplete)
170                 commit->object.flags |= INCOMPLETE;
171         else {
172                 /*
173                  * If we come here, we have (1) traversed the ancestry chain
174                  * from the "commit" until we reach SEEN commits (which are
175                  * known to be complete), and (2) made sure that the commits
176                  * encountered during the above traversal refer to trees that
177                  * are complete.  Which means that we know *all* the commits
178                  * we have seen during this process are complete.
179                  */
180                 for (i = 0; i < found.nr; i++)
181                         found.objects[i].item->flags |= SEEN;
182         }
183         /* free object arrays */
184         free(study.objects);
185         free(found.objects);
186         return !is_incomplete;
187 }
188
189 static int keep_entry(struct commit **it, unsigned char *sha1)
190 {
191         struct commit *commit;
192
193         if (is_null_sha1(sha1))
194                 return 1;
195         commit = lookup_commit_reference_gently(sha1, 1);
196         if (!commit)
197                 return 0;
198
199         /*
200          * Make sure everything in this commit exists.
201          *
202          * We have walked all the objects reachable from the refs
203          * and cache earlier.  The commits reachable by this commit
204          * must meet SEEN commits -- and then we should mark them as
205          * SEEN as well.
206          */
207         if (!commit_is_complete(commit))
208                 return 0;
209         *it = commit;
210         return 1;
211 }
212
213 /*
214  * Starting from commits in the cb->mark_list, mark commits that are
215  * reachable from them.  Stop the traversal at commits older than
216  * the expire_limit and queue them back, so that the caller can call
217  * us again to restart the traversal with longer expire_limit.
218  */
219 static void mark_reachable(struct expire_reflog_policy_cb *cb)
220 {
221         struct commit_list *pending;
222         unsigned long expire_limit = cb->mark_limit;
223         struct commit_list *leftover = NULL;
224
225         for (pending = cb->mark_list; pending; pending = pending->next)
226                 pending->item->object.flags &= ~REACHABLE;
227
228         pending = cb->mark_list;
229         while (pending) {
230                 struct commit_list *parent;
231                 struct commit *commit = pop_commit(&pending);
232                 if (commit->object.flags & REACHABLE)
233                         continue;
234                 if (parse_commit(commit))
235                         continue;
236                 commit->object.flags |= REACHABLE;
237                 if (commit->date < expire_limit) {
238                         commit_list_insert(commit, &leftover);
239                         continue;
240                 }
241                 commit->object.flags |= REACHABLE;
242                 parent = commit->parents;
243                 while (parent) {
244                         commit = parent->item;
245                         parent = parent->next;
246                         if (commit->object.flags & REACHABLE)
247                                 continue;
248                         commit_list_insert(commit, &pending);
249                 }
250         }
251         cb->mark_list = leftover;
252 }
253
254 static int unreachable(struct expire_reflog_policy_cb *cb, struct commit *commit, unsigned char *sha1)
255 {
256         /*
257          * We may or may not have the commit yet - if not, look it
258          * up using the supplied sha1.
259          */
260         if (!commit) {
261                 if (is_null_sha1(sha1))
262                         return 0;
263
264                 commit = lookup_commit_reference_gently(sha1, 1);
265
266                 /* Not a commit -- keep it */
267                 if (!commit)
268                         return 0;
269         }
270
271         /* Reachable from the current ref?  Don't prune. */
272         if (commit->object.flags & REACHABLE)
273                 return 0;
274
275         if (cb->mark_list && cb->mark_limit) {
276                 cb->mark_limit = 0; /* dig down to the root */
277                 mark_reachable(cb);
278         }
279
280         return !(commit->object.flags & REACHABLE);
281 }
282
283 /*
284  * Return true iff the specified reflog entry should be expired.
285  */
286 static int should_expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
287                                     const char *email, unsigned long timestamp, int tz,
288                                     const char *message, void *cb_data)
289 {
290         struct expire_reflog_policy_cb *cb = cb_data;
291         struct commit *old, *new;
292
293         if (timestamp < cb->cmd.expire_total)
294                 return 1;
295
296         old = new = NULL;
297         if (cb->cmd.stalefix &&
298             (!keep_entry(&old, osha1) || !keep_entry(&new, nsha1)))
299                 return 1;
300
301         if (timestamp < cb->cmd.expire_unreachable) {
302                 if (cb->unreachable_expire_kind == UE_ALWAYS)
303                         return 1;
304                 if (unreachable(cb, old, osha1) || unreachable(cb, new, nsha1))
305                         return 1;
306         }
307
308         if (cb->cmd.recno && --(cb->cmd.recno) == 0)
309                 return 1;
310
311         return 0;
312 }
313
314 static int push_tip_to_list(const char *refname, const struct object_id *oid,
315                             int flags, void *cb_data)
316 {
317         struct commit_list **list = cb_data;
318         struct commit *tip_commit;
319         if (flags & REF_ISSYMREF)
320                 return 0;
321         tip_commit = lookup_commit_reference_gently(oid->hash, 1);
322         if (!tip_commit)
323                 return 0;
324         commit_list_insert(tip_commit, list);
325         return 0;
326 }
327
328 static void reflog_expiry_prepare(const char *refname,
329                                   const unsigned char *sha1,
330                                   void *cb_data)
331 {
332         struct expire_reflog_policy_cb *cb = cb_data;
333
334         if (!cb->cmd.expire_unreachable || !strcmp(refname, "HEAD")) {
335                 cb->tip_commit = NULL;
336                 cb->unreachable_expire_kind = UE_HEAD;
337         } else {
338                 cb->tip_commit = lookup_commit_reference_gently(sha1, 1);
339                 if (!cb->tip_commit)
340                         cb->unreachable_expire_kind = UE_ALWAYS;
341                 else
342                         cb->unreachable_expire_kind = UE_NORMAL;
343         }
344
345         if (cb->cmd.expire_unreachable <= cb->cmd.expire_total)
346                 cb->unreachable_expire_kind = UE_ALWAYS;
347
348         cb->mark_list = NULL;
349         cb->tips = NULL;
350         if (cb->unreachable_expire_kind != UE_ALWAYS) {
351                 if (cb->unreachable_expire_kind == UE_HEAD) {
352                         struct commit_list *elem;
353
354                         for_each_ref(push_tip_to_list, &cb->tips);
355                         for (elem = cb->tips; elem; elem = elem->next)
356                                 commit_list_insert(elem->item, &cb->mark_list);
357                 } else {
358                         commit_list_insert(cb->tip_commit, &cb->mark_list);
359                 }
360                 cb->mark_limit = cb->cmd.expire_total;
361                 mark_reachable(cb);
362         }
363 }
364
365 static void reflog_expiry_cleanup(void *cb_data)
366 {
367         struct expire_reflog_policy_cb *cb = cb_data;
368
369         if (cb->unreachable_expire_kind != UE_ALWAYS) {
370                 if (cb->unreachable_expire_kind == UE_HEAD) {
371                         struct commit_list *elem;
372                         for (elem = cb->tips; elem; elem = elem->next)
373                                 clear_commit_marks(elem->item, REACHABLE);
374                         free_commit_list(cb->tips);
375                 } else {
376                         clear_commit_marks(cb->tip_commit, REACHABLE);
377                 }
378         }
379 }
380
381 static int collect_reflog(const char *ref, const struct object_id *oid, int unused, void *cb_data)
382 {
383         struct collected_reflog *e;
384         struct collect_reflog_cb *cb = cb_data;
385
386         FLEX_ALLOC_STR(e, reflog, ref);
387         hashcpy(e->sha1, oid->hash);
388         ALLOC_GROW(cb->e, cb->nr + 1, cb->alloc);
389         cb->e[cb->nr++] = e;
390         return 0;
391 }
392
393 static struct reflog_expire_cfg {
394         struct reflog_expire_cfg *next;
395         unsigned long expire_total;
396         unsigned long expire_unreachable;
397         char pattern[FLEX_ARRAY];
398 } *reflog_expire_cfg, **reflog_expire_cfg_tail;
399
400 static struct reflog_expire_cfg *find_cfg_ent(const char *pattern, size_t len)
401 {
402         struct reflog_expire_cfg *ent;
403
404         if (!reflog_expire_cfg_tail)
405                 reflog_expire_cfg_tail = &reflog_expire_cfg;
406
407         for (ent = reflog_expire_cfg; ent; ent = ent->next)
408                 if (!strncmp(ent->pattern, pattern, len) &&
409                     ent->pattern[len] == '\0')
410                         return ent;
411
412         FLEX_ALLOC_MEM(ent, pattern, pattern, len);
413         *reflog_expire_cfg_tail = ent;
414         reflog_expire_cfg_tail = &(ent->next);
415         return ent;
416 }
417
418 static int parse_expire_cfg_value(const char *var, const char *value, unsigned long *expire)
419 {
420         if (!value)
421                 return config_error_nonbool(var);
422         if (parse_expiry_date(value, expire))
423                 return error(_("'%s' for '%s' is not a valid timestamp"),
424                              value, var);
425         return 0;
426 }
427
428 /* expiry timer slot */
429 #define EXPIRE_TOTAL   01
430 #define EXPIRE_UNREACH 02
431
432 static int reflog_expire_config(const char *var, const char *value, void *cb)
433 {
434         const char *pattern, *key;
435         int pattern_len;
436         unsigned long expire;
437         int slot;
438         struct reflog_expire_cfg *ent;
439
440         if (parse_config_key(var, "gc", &pattern, &pattern_len, &key) < 0)
441                 return git_default_config(var, value, cb);
442
443         if (!strcmp(key, "reflogexpire")) {
444                 slot = EXPIRE_TOTAL;
445                 if (parse_expire_cfg_value(var, value, &expire))
446                         return -1;
447         } else if (!strcmp(key, "reflogexpireunreachable")) {
448                 slot = EXPIRE_UNREACH;
449                 if (parse_expire_cfg_value(var, value, &expire))
450                         return -1;
451         } else
452                 return git_default_config(var, value, cb);
453
454         if (!pattern) {
455                 switch (slot) {
456                 case EXPIRE_TOTAL:
457                         default_reflog_expire = expire;
458                         break;
459                 case EXPIRE_UNREACH:
460                         default_reflog_expire_unreachable = expire;
461                         break;
462                 }
463                 return 0;
464         }
465
466         ent = find_cfg_ent(pattern, pattern_len);
467         if (!ent)
468                 return -1;
469         switch (slot) {
470         case EXPIRE_TOTAL:
471                 ent->expire_total = expire;
472                 break;
473         case EXPIRE_UNREACH:
474                 ent->expire_unreachable = expire;
475                 break;
476         }
477         return 0;
478 }
479
480 static void set_reflog_expiry_param(struct cmd_reflog_expire_cb *cb, int slot, const char *ref)
481 {
482         struct reflog_expire_cfg *ent;
483
484         if (slot == (EXPIRE_TOTAL|EXPIRE_UNREACH))
485                 return; /* both given explicitly -- nothing to tweak */
486
487         for (ent = reflog_expire_cfg; ent; ent = ent->next) {
488                 if (!wildmatch(ent->pattern, ref, 0, NULL)) {
489                         if (!(slot & EXPIRE_TOTAL))
490                                 cb->expire_total = ent->expire_total;
491                         if (!(slot & EXPIRE_UNREACH))
492                                 cb->expire_unreachable = ent->expire_unreachable;
493                         return;
494                 }
495         }
496
497         /*
498          * If unconfigured, make stash never expire
499          */
500         if (!strcmp(ref, "refs/stash")) {
501                 if (!(slot & EXPIRE_TOTAL))
502                         cb->expire_total = 0;
503                 if (!(slot & EXPIRE_UNREACH))
504                         cb->expire_unreachable = 0;
505                 return;
506         }
507
508         /* Nothing matched -- use the default value */
509         if (!(slot & EXPIRE_TOTAL))
510                 cb->expire_total = default_reflog_expire;
511         if (!(slot & EXPIRE_UNREACH))
512                 cb->expire_unreachable = default_reflog_expire_unreachable;
513 }
514
515 static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
516 {
517         struct expire_reflog_policy_cb cb;
518         unsigned long now = time(NULL);
519         int i, status, do_all;
520         int explicit_expiry = 0;
521         unsigned int flags = 0;
522
523         default_reflog_expire_unreachable = now - 30 * 24 * 3600;
524         default_reflog_expire = now - 90 * 24 * 3600;
525         git_config(reflog_expire_config, NULL);
526
527         save_commit_buffer = 0;
528         do_all = status = 0;
529         memset(&cb, 0, sizeof(cb));
530
531         cb.cmd.expire_total = default_reflog_expire;
532         cb.cmd.expire_unreachable = default_reflog_expire_unreachable;
533
534         for (i = 1; i < argc; i++) {
535                 const char *arg = argv[i];
536                 if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
537                         flags |= EXPIRE_REFLOGS_DRY_RUN;
538                 else if (starts_with(arg, "--expire=")) {
539                         if (parse_expiry_date(arg + 9, &cb.cmd.expire_total))
540                                 die(_("'%s' is not a valid timestamp"), arg);
541                         explicit_expiry |= EXPIRE_TOTAL;
542                 }
543                 else if (starts_with(arg, "--expire-unreachable=")) {
544                         if (parse_expiry_date(arg + 21, &cb.cmd.expire_unreachable))
545                                 die(_("'%s' is not a valid timestamp"), arg);
546                         explicit_expiry |= EXPIRE_UNREACH;
547                 }
548                 else if (!strcmp(arg, "--stale-fix"))
549                         cb.cmd.stalefix = 1;
550                 else if (!strcmp(arg, "--rewrite"))
551                         flags |= EXPIRE_REFLOGS_REWRITE;
552                 else if (!strcmp(arg, "--updateref"))
553                         flags |= EXPIRE_REFLOGS_UPDATE_REF;
554                 else if (!strcmp(arg, "--all"))
555                         do_all = 1;
556                 else if (!strcmp(arg, "--verbose"))
557                         flags |= EXPIRE_REFLOGS_VERBOSE;
558                 else if (!strcmp(arg, "--")) {
559                         i++;
560                         break;
561                 }
562                 else if (arg[0] == '-')
563                         usage(reflog_expire_usage);
564                 else
565                         break;
566         }
567
568         /*
569          * We can trust the commits and objects reachable from refs
570          * even in older repository.  We cannot trust what's reachable
571          * from reflog if the repository was pruned with older git.
572          */
573         if (cb.cmd.stalefix) {
574                 init_revisions(&cb.cmd.revs, prefix);
575                 if (flags & EXPIRE_REFLOGS_VERBOSE)
576                         printf("Marking reachable objects...");
577                 mark_reachable_objects(&cb.cmd.revs, 0, 0, NULL);
578                 if (flags & EXPIRE_REFLOGS_VERBOSE)
579                         putchar('\n');
580         }
581
582         if (do_all) {
583                 struct collect_reflog_cb collected;
584                 int i;
585
586                 memset(&collected, 0, sizeof(collected));
587                 for_each_reflog(collect_reflog, &collected);
588                 for (i = 0; i < collected.nr; i++) {
589                         struct collected_reflog *e = collected.e[i];
590                         set_reflog_expiry_param(&cb.cmd, explicit_expiry, e->reflog);
591                         status |= reflog_expire(e->reflog, e->sha1, flags,
592                                                 reflog_expiry_prepare,
593                                                 should_expire_reflog_ent,
594                                                 reflog_expiry_cleanup,
595                                                 &cb);
596                         free(e);
597                 }
598                 free(collected.e);
599         }
600
601         for (; i < argc; i++) {
602                 char *ref;
603                 unsigned char sha1[20];
604                 if (!dwim_log(argv[i], strlen(argv[i]), sha1, &ref)) {
605                         status |= error("%s points nowhere!", argv[i]);
606                         continue;
607                 }
608                 set_reflog_expiry_param(&cb.cmd, explicit_expiry, ref);
609                 status |= reflog_expire(ref, sha1, flags,
610                                         reflog_expiry_prepare,
611                                         should_expire_reflog_ent,
612                                         reflog_expiry_cleanup,
613                                         &cb);
614         }
615         return status;
616 }
617
618 static int count_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
619                 const char *email, unsigned long timestamp, int tz,
620                 const char *message, void *cb_data)
621 {
622         struct expire_reflog_policy_cb *cb = cb_data;
623         if (!cb->cmd.expire_total || timestamp < cb->cmd.expire_total)
624                 cb->cmd.recno++;
625         return 0;
626 }
627
628 static int cmd_reflog_delete(int argc, const char **argv, const char *prefix)
629 {
630         struct expire_reflog_policy_cb cb;
631         int i, status = 0;
632         unsigned int flags = 0;
633
634         memset(&cb, 0, sizeof(cb));
635
636         for (i = 1; i < argc; i++) {
637                 const char *arg = argv[i];
638                 if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
639                         flags |= EXPIRE_REFLOGS_DRY_RUN;
640                 else if (!strcmp(arg, "--rewrite"))
641                         flags |= EXPIRE_REFLOGS_REWRITE;
642                 else if (!strcmp(arg, "--updateref"))
643                         flags |= EXPIRE_REFLOGS_UPDATE_REF;
644                 else if (!strcmp(arg, "--verbose"))
645                         flags |= EXPIRE_REFLOGS_VERBOSE;
646                 else if (!strcmp(arg, "--")) {
647                         i++;
648                         break;
649                 }
650                 else if (arg[0] == '-')
651                         usage(reflog_delete_usage);
652                 else
653                         break;
654         }
655
656         if (argc - i < 1)
657                 return error("Nothing to delete?");
658
659         for ( ; i < argc; i++) {
660                 const char *spec = strstr(argv[i], "@{");
661                 unsigned char sha1[20];
662                 char *ep, *ref;
663                 int recno;
664
665                 if (!spec) {
666                         status |= error("Not a reflog: %s", argv[i]);
667                         continue;
668                 }
669
670                 if (!dwim_log(argv[i], spec - argv[i], sha1, &ref)) {
671                         status |= error("no reflog for '%s'", argv[i]);
672                         continue;
673                 }
674
675                 recno = strtoul(spec + 2, &ep, 10);
676                 if (*ep == '}') {
677                         cb.cmd.recno = -recno;
678                         for_each_reflog_ent(ref, count_reflog_ent, &cb);
679                 } else {
680                         cb.cmd.expire_total = approxidate(spec + 2);
681                         for_each_reflog_ent(ref, count_reflog_ent, &cb);
682                         cb.cmd.expire_total = 0;
683                 }
684
685                 status |= reflog_expire(ref, sha1, flags,
686                                         reflog_expiry_prepare,
687                                         should_expire_reflog_ent,
688                                         reflog_expiry_cleanup,
689                                         &cb);
690                 free(ref);
691         }
692         return status;
693 }
694
695 static int cmd_reflog_exists(int argc, const char **argv, const char *prefix)
696 {
697         int i, start = 0;
698
699         for (i = 1; i < argc; i++) {
700                 const char *arg = argv[i];
701                 if (!strcmp(arg, "--")) {
702                         i++;
703                         break;
704                 }
705                 else if (arg[0] == '-')
706                         usage(reflog_exists_usage);
707                 else
708                         break;
709         }
710
711         start = i;
712
713         if (argc - start != 1)
714                 usage(reflog_exists_usage);
715
716         if (check_refname_format(argv[start], REFNAME_ALLOW_ONELEVEL))
717                 die("invalid ref format: %s", argv[start]);
718         return !reflog_exists(argv[start]);
719 }
720
721 /*
722  * main "reflog"
723  */
724
725 static const char reflog_usage[] =
726 "git reflog [ show | expire | delete | exists ]";
727
728 int cmd_reflog(int argc, const char **argv, const char *prefix)
729 {
730         if (argc > 1 && !strcmp(argv[1], "-h"))
731                 usage(reflog_usage);
732
733         /* With no command, we default to showing it. */
734         if (argc < 2 || *argv[1] == '-')
735                 return cmd_log_reflog(argc, argv, prefix);
736
737         if (!strcmp(argv[1], "show"))
738                 return cmd_log_reflog(argc - 1, argv + 1, prefix);
739
740         if (!strcmp(argv[1], "expire"))
741                 return cmd_reflog_expire(argc - 1, argv + 1, prefix);
742
743         if (!strcmp(argv[1], "delete"))
744                 return cmd_reflog_delete(argc - 1, argv + 1, prefix);
745
746         if (!strcmp(argv[1], "exists"))
747                 return cmd_reflog_exists(argc - 1, argv + 1, prefix);
748
749         return cmd_log_reflog(argc, argv, prefix);
750 }