aboutsummaryrefslogtreecommitdiff
path: root/builtin/reflog.c
blob: 2d85d260ca66deb060b837f86d81a7aad2761b69 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
#include "builtin.h"
#include "lockfile.h"
#include "commit.h"
#include "refs.h"
#include "dir.h"
#include "tree-walk.h"
#include "diff.h"
#include "revision.h"
#include "reachable.h"

/*
 * reflog expire
 */

static const char reflog_expire_usage[] =
"git reflog expire [--verbose] [--dry-run] [--stale-fix] [--expire=<time>] [--expire-unreachable=<time>] [--all] <refs>...";
static const char reflog_delete_usage[] =
"git reflog delete [--verbose] [--dry-run] [--rewrite] [--updateref] <refs>...";

static unsigned long default_reflog_expire;
static unsigned long default_reflog_expire_unreachable;

struct cmd_reflog_expire_cb {
	struct rev_info revs;
	int dry_run;
	int stalefix;
	int rewrite;
	int updateref;
	int verbose;
	unsigned long expire_total;
	unsigned long expire_unreachable;
	int recno;
};

struct expire_reflog_cb {
	FILE *newlog;
	enum {
		UE_NORMAL,
		UE_ALWAYS,
		UE_HEAD
	} unreachable_expire_kind;
	struct commit_list *mark_list;
	unsigned long mark_limit;
	struct cmd_reflog_expire_cb *cmd;
	unsigned char last_kept_sha1[20];
};

struct collected_reflog {
	unsigned char sha1[20];
	char reflog[FLEX_ARRAY];
};
struct collect_reflog_cb {
	struct collected_reflog **e;
	int alloc;
	int nr;
};

#define INCOMPLETE	(1u<<10)
#define STUDYING	(1u<<11)
#define REACHABLE	(1u<<12)

static int tree_is_complete(const unsigned char *sha1)
{
	struct tree_desc desc;
	struct name_entry entry;
	int complete;
	struct tree *tree;

	tree = lookup_tree(sha1);
	if (!tree)
		return 0;
	if (tree->object.flags & SEEN)
		return 1;
	if (tree->object.flags & INCOMPLETE)
		return 0;

	if (!tree->buffer) {
		enum object_type type;
		unsigned long size;
		void *data = read_sha1_file(sha1, &type, &size);
		if (!data) {
			tree->object.flags |= INCOMPLETE;
			return 0;
		}
		tree->buffer = data;
		tree->size = size;
	}
	init_tree_desc(&desc, tree->buffer, tree->size);
	complete = 1;
	while (tree_entry(&desc, &entry)) {
		if (!has_sha1_file(entry.sha1) ||
		    (S_ISDIR(entry.mode) && !tree_is_complete(entry.sha1))) {
			tree->object.flags |= INCOMPLETE;
			complete = 0;
		}
	}
	free_tree_buffer(tree);

	if (complete)
		tree->object.flags |= SEEN;
	return complete;
}

static int commit_is_complete(struct commit *commit)
{
	struct object_array study;
	struct object_array found;
	int is_incomplete = 0;
	int i;

	/* early return */
	if (commit->object.flags & SEEN)
		return 1;
	if (commit->object.flags & INCOMPLETE)
		return 0;
	/*
	 * Find all commits that are reachable and are not marked as
	 * SEEN.  Then make sure the trees and blobs contained are
	 * complete.  After that, mark these commits also as SEEN.
	 * If some of the objects that are needed to complete this
	 * commit are missing, mark this commit as INCOMPLETE.
	 */
	memset(&study, 0, sizeof(study));
	memset(&found, 0, sizeof(found));
	add_object_array(&commit->object, NULL, &study);
	add_object_array(&commit->object, NULL, &found);
	commit->object.flags |= STUDYING;
	while (study.nr) {
		struct commit *c;
		struct commit_list *parent;

		c = (struct commit *)study.objects[--study.nr].item;
		if (!c->object.parsed && !parse_object(c->object.sha1))
			c->object.flags |= INCOMPLETE;

		if (c->object.flags & INCOMPLETE) {
			is_incomplete = 1;
			break;
		}
		else if (c->object.flags & SEEN)
			continue;
		for (parent = c->parents; parent; parent = parent->next) {
			struct commit *p = parent->item;
			if (p->object.flags & STUDYING)
				continue;
			p->object.flags |= STUDYING;
			add_object_array(&p->object, NULL, &study);
			add_object_array(&p->object, NULL, &found);
		}
	}
	if (!is_incomplete) {
		/*
		 * make sure all commits in "found" array have all the
		 * necessary objects.
		 */
		for (i = 0; i < found.nr; i++) {
			struct commit *c =
				(struct commit *)found.objects[i].item;
			if (!tree_is_complete(c->tree->object.sha1)) {
				is_incomplete = 1;
				c->object.flags |= INCOMPLETE;
			}
		}
		if (!is_incomplete) {
			/* mark all found commits as complete, iow SEEN */
			for (i = 0; i < found.nr; i++)
				found.objects[i].item->flags |= SEEN;
		}
	}
	/* clear flags from the objects we traversed */
	for (i = 0; i < found.nr; i++)
		found.objects[i].item->flags &= ~STUDYING;
	if (is_incomplete)
		commit->object.flags |= INCOMPLETE;
	else {
		/*
		 * If we come here, we have (1) traversed the ancestry chain
		 * from the "commit" until we reach SEEN commits (which are
		 * known to be complete), and (2) made sure that the commits
		 * encountered during the above traversal refer to trees that
		 * are complete.  Which means that we know *all* the commits
		 * we have seen during this process are complete.
		 */
		for (i = 0; i < found.nr; i++)
			found.objects[i].item->flags |= SEEN;
	}
	/* free object arrays */
	free(study.objects);
	free(found.objects);
	return !is_incomplete;
}

static int keep_entry(struct commit **it, unsigned char *sha1)
{
	struct commit *commit;

	if (is_null_sha1(sha1))
		return 1;
	commit = lookup_commit_reference_gently(sha1, 1);
	if (!commit)
		return 0;

	/*
	 * Make sure everything in this commit exists.
	 *
	 * We have walked all the objects reachable from the refs
	 * and cache earlier.  The commits reachable by this commit
	 * must meet SEEN commits -- and then we should mark them as
	 * SEEN as well.
	 */
	if (!commit_is_complete(commit))
		return 0;
	*it = commit;
	return 1;
}

/*
 * Starting from commits in the cb->mark_list, mark commits that are
 * reachable from them.  Stop the traversal at commits older than
 * the expire_limit and queue them back, so that the caller can call
 * us again to restart the traversal with longer expire_limit.
 */
static void mark_reachable(struct expire_reflog_cb *cb)
{
	struct commit *commit;
	struct commit_list *pending;
	unsigned long expire_limit = cb->mark_limit;
	struct commit_list *leftover = NULL;

	for (pending = cb->mark_list; pending; pending = pending->next)
		pending->item->object.flags &= ~REACHABLE;

	pending = cb->mark_list;
	while (pending) {
		struct commit_list *entry = pending;
		struct commit_list *parent;
		pending = entry->next;
		commit = entry->item;
		free(entry);
		if (commit->object.flags & REACHABLE)
			continue;
		if (parse_commit(commit))
			continue;
		commit->object.flags |= REACHABLE;
		if (commit->date < expire_limit) {
			commit_list_insert(commit, &leftover);
			continue;
		}
		commit->object.flags |= REACHABLE;
		parent = commit->parents;
		while (parent) {
			commit = parent->item;
			parent = parent->next;
			if (commit->object.flags & REACHABLE)
				continue;
			commit_list_insert(commit, &pending);
		}
	}
	cb->mark_list = leftover;
}

static int unreachable(struct expire_reflog_cb *cb, struct commit *commit, unsigned char *sha1)
{
	/*
	 * We may or may not have the commit yet - if not, look it
	 * up using the supplied sha1.
	 */
	if (!commit) {
		if (is_null_sha1(sha1))
			return 0;

		commit = lookup_commit_reference_gently(sha1, 1);

		/* Not a commit -- keep it */
		if (!commit)
			return 0;
	}

	/* Reachable from the current ref?  Don't prune. */
	if (commit->object.flags & REACHABLE)
		return 0;

	if (cb->mark_list && cb->mark_limit) {
		cb->mark_limit = 0; /* dig down to the root */
		mark_reachable(cb);
	}

	return !(commit->object.flags & REACHABLE);
}

static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
		const char *email, unsigned long timestamp, int tz,
		const char *message, void *cb_data)
{
	struct expire_reflog_cb *cb = cb_data;
	struct commit *old, *new;

	if (timestamp < cb->cmd->expire_total)
		goto prune;

	if (cb->cmd->rewrite)
		osha1 = cb->last_kept_sha1;

	old = new = NULL;
	if (cb->cmd->stalefix &&
	    (!keep_entry(&old, osha1) || !keep_entry(&new, nsha1)))
		goto prune;

	if (timestamp < cb->cmd->expire_unreachable) {
		if (cb->unreachable_expire_kind == UE_ALWAYS)
			goto prune;
		if (unreachable(cb, old, osha1) || unreachable(cb, new, nsha1))
			goto prune;
	}

	if (cb->cmd->recno && --(cb->cmd->recno) == 0)
		goto prune;

	if (cb->newlog) {
		char sign = (tz < 0) ? '-' : '+';
		int zone = (tz < 0) ? (-tz) : tz;
		fprintf(cb->newlog, "%s %s %s %lu %c%04d\t%s",
			sha1_to_hex(osha1), sha1_to_hex(nsha1),
			email, timestamp, sign, zone,
			message);
		hashcpy(cb->last_kept_sha1, nsha1);
	}
	if (cb->cmd->verbose)
		printf("keep %s", message);
	return 0;
 prune:
	if (!cb->newlog)
		printf("would prune %s", message);
	else if (cb->cmd->verbose)
		printf("prune %s", message);
	return 0;
}

static int push_tip_to_list(const char *refname, const unsigned char *sha1, int flags, void *cb_data)
{
	struct commit_list **list = cb_data;
	struct commit *tip_commit;
	if (flags & REF_ISSYMREF)
		return 0;
	tip_commit = lookup_commit_reference_gently(sha1, 1);
	if (!tip_commit)
		return 0;
	commit_list_insert(tip_commit, list);
	return 0;
}

static int expire_reflog(const char *ref, const unsigned char *sha1, int unused, void *cb_data)
{
	struct cmd_reflog_expire_cb *cmd = cb_data;
	struct expire_reflog_cb cb;
	struct ref_lock *lock;
	char *log_file, *newlog_path = NULL;
	struct commit *tip_commit;
	struct commit_list *tips;
	int status = 0;

	memset(&cb, 0, sizeof(cb));

	/*
	 * we take the lock for the ref itself to prevent it from
	 * getting updated.
	 */
	lock = lock_any_ref_for_update(ref, sha1, 0, NULL);
	if (!lock)
		return error("cannot lock ref '%s'", ref);
	log_file = git_pathdup("logs/%s", ref);
	if (!reflog_exists(ref))
		goto finish;
	if (!cmd->dry_run) {
		newlog_path = git_pathdup("logs/%s.lock", ref);
		cb.newlog = fopen(newlog_path, "w");
	}

	cb.cmd = cmd;

	if (!cmd->expire_unreachable || !strcmp(ref, "HEAD")) {
		tip_commit = NULL;
		cb.unreachable_expire_kind = UE_HEAD;
	} else {
		tip_commit = lookup_commit_reference_gently(sha1, 1);
		if (!tip_commit)
			cb.unreachable_expire_kind = UE_ALWAYS;
		else
			cb.unreachable_expire_kind = UE_NORMAL;
	}

	if (cmd->expire_unreachable <= cmd->expire_total)
		cb.unreachable_expire_kind = UE_ALWAYS;

	cb.mark_list = NULL;
	tips = NULL;
	if (cb.unreachable_expire_kind != UE_ALWAYS) {
		if (cb.unreachable_expire_kind == UE_HEAD) {
			struct commit_list *elem;
			for_each_ref(push_tip_to_list, &tips);
			for (elem = tips; elem; elem = elem->next)
				commit_list_insert(elem->item, &cb.mark_list);
		} else {
			commit_list_insert(tip_commit, &cb.mark_list);
		}
		cb.mark_limit = cmd->expire_total;
		mark_reachable(&cb);
	}

	for_each_reflog_ent(ref, expire_reflog_ent, &cb);

	if (cb.unreachable_expire_kind != UE_ALWAYS) {
		if (cb.unreachable_expire_kind == UE_HEAD) {
			struct commit_list *elem;
			for (elem = tips; elem; elem = elem->next)
				clear_commit_marks(elem->item, REACHABLE);
			free_commit_list(tips);
		} else {
			clear_commit_marks(tip_commit, REACHABLE);
		}
	}
 finish:
	if (cb.newlog) {
		if (fclose(cb.newlog)) {
			status |= error("%s: %s", strerror(errno),
					newlog_path);
			unlink(newlog_path);
		} else if (cmd->updateref &&
			(write_in_full(lock->lock_fd,
				sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
			 write_str_in_full(lock->lock_fd, "\n") != 1 ||
			 close_ref(lock) < 0)) {
			status |= error("Couldn't write %s",
					lock->lk->filename.buf);
			unlink(newlog_path);
		} else if (rename(newlog_path, log_file)) {
			status |= error("cannot rename %s to %s",
					newlog_path, log_file);
			unlink(newlog_path);
		} else if (cmd->updateref && commit_ref(lock)) {
			status |= error("Couldn't set %s", lock->ref_name);
		} else {
			adjust_shared_perm(log_file);
		}
	}
	free(newlog_path);
	free(log_file);
	unlock_ref(lock);
	return status;
}

static int collect_reflog(const char *ref, const unsigned char *sha1, int unused, void *cb_data)
{
	struct collected_reflog *e;
	struct collect_reflog_cb *cb = cb_data;
	size_t namelen = strlen(ref);

	e = xmalloc(sizeof(*e) + namelen + 1);
	hashcpy(e->sha1, sha1);
	memcpy(e->reflog, ref, namelen + 1);
	ALLOC_GROW(cb->e, cb->nr + 1, cb->alloc);
	cb->e[cb->nr++] = e;
	return 0;
}

static struct reflog_expire_cfg {
	struct reflog_expire_cfg *next;
	unsigned long expire_total;
	unsigned long expire_unreachable;
	size_t len;
	char pattern[FLEX_ARRAY];
} *reflog_expire_cfg, **reflog_expire_cfg_tail;

static struct reflog_expire_cfg *find_cfg_ent(const char *pattern, size_t len)
{
	struct reflog_expire_cfg *ent;

	if (!reflog_expire_cfg_tail)
		reflog_expire_cfg_tail = &reflog_expire_cfg;

	for (ent = reflog_expire_cfg; ent; ent = ent->next)
		if (ent->len == len &&
		    !memcmp(ent->pattern, pattern, len))
			return ent;

	ent = xcalloc(1, (sizeof(*ent) + len));
	memcpy(ent->pattern, pattern, len);
	ent->len = len;
	*reflog_expire_cfg_tail = ent;
	reflog_expire_cfg_tail = &(ent->next);
	return ent;
}

static int parse_expire_cfg_value(const char *var, const char *value, unsigned long *expire)
{
	if (!value)
		return config_error_nonbool(var);
	if (parse_expiry_date(value, expire))
		return error(_("%s' for '%s' is not a valid timestamp"),
			     value, var);
	return 0;
}

/* expiry timer slot */
#define EXPIRE_TOTAL   01
#define EXPIRE_UNREACH 02

static int reflog_expire_config(const char *var, const char *value, void *cb)
{
	const char *pattern, *key;
	int pattern_len;
	unsigned long expire;
	int slot;
	struct reflog_expire_cfg *ent;

	if (parse_config_key(var, "gc", &pattern, &pattern_len, &key) < 0)
		return git_default_config(var, value, cb);

	if (!strcmp(key, "reflogexpire")) {
		slot = EXPIRE_TOTAL;
		if (parse_expire_cfg_value(var, value, &expire))
			return -1;
	} else if (!strcmp(key, "reflogexpireunreachable")) {
		slot = EXPIRE_UNREACH;
		if (parse_expire_cfg_value(var, value, &expire))
			return -1;
	} else
		return git_default_config(var, value, cb);

	if (!pattern) {
		switch (slot) {
		case EXPIRE_TOTAL:
			default_reflog_expire = expire;
			break;
		case EXPIRE_UNREACH:
			default_reflog_expire_unreachable = expire;
			break;
		}
		return 0;
	}

	ent = find_cfg_ent(pattern, pattern_len);
	if (!ent)
		return -1;
	switch (slot) {
	case EXPIRE_TOTAL:
		ent->expire_total = expire;
		break;
	case EXPIRE_UNREACH:
		ent->expire_unreachable = expire;
		break;
	}
	return 0;
}

static void set_reflog_expiry_param(struct cmd_reflog_expire_cb *cb, int slot, const char *ref)
{
	struct reflog_expire_cfg *ent;

	if (slot == (EXPIRE_TOTAL|EXPIRE_UNREACH))
		return; /* both given explicitly -- nothing to tweak */

	for (ent = reflog_expire_cfg; ent; ent = ent->next) {
		if (!wildmatch(ent->pattern, ref, 0, NULL)) {
			if (!(slot & EXPIRE_TOTAL))
				cb->expire_total = ent->expire_total;
			if (!(slot & EXPIRE_UNREACH))
				cb->expire_unreachable = ent->expire_unreachable;
			return;
		}
	}

	/*
	 * If unconfigured, make stash never expire
	 */
	if (!strcmp(ref, "refs/stash")) {
		if (!(slot & EXPIRE_TOTAL))
			cb->expire_total = 0;
		if (!(slot & EXPIRE_UNREACH))
			cb->expire_unreachable = 0;
		return;
	}

	/* Nothing matched -- use the default value */
	if (!(slot & EXPIRE_TOTAL))
		cb->expire_total = default_reflog_expire;
	if (!(slot & EXPIRE_UNREACH))
		cb->expire_unreachable = default_reflog_expire_unreachable;
}

static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
{
	struct cmd_reflog_expire_cb cb;
	unsigned long now = time(NULL);
	int i, status, do_all;
	int explicit_expiry = 0;

	default_reflog_expire_unreachable = now - 30 * 24 * 3600;
	default_reflog_expire = now - 90 * 24 * 3600;
	git_config(reflog_expire_config, NULL);

	save_commit_buffer = 0;
	do_all = status = 0;
	memset(&cb, 0, sizeof(cb));

	cb.expire_total = default_reflog_expire;
	cb.expire_unreachable = default_reflog_expire_unreachable;

	for (i = 1; i < argc; i++) {
		const char *arg = argv[i];
		if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
			cb.dry_run = 1;
		else if (starts_with(arg, "--expire=")) {
			if (parse_expiry_date(arg + 9, &cb.expire_total))
				die(_("'%s' is not a valid timestamp"), arg);
			explicit_expiry |= EXPIRE_TOTAL;
		}
		else if (starts_with(arg, "--expire-unreachable=")) {
			if (parse_expiry_date(arg + 21, &cb.expire_unreachable))
				die(_("'%s' is not a valid timestamp"), arg);
			explicit_expiry |= EXPIRE_UNREACH;
		}
		else if (!strcmp(arg, "--stale-fix"))
			cb.stalefix = 1;
		else if (!strcmp(arg, "--rewrite"))
			cb.rewrite = 1;
		else if (!strcmp(arg, "--updateref"))
			cb.updateref = 1;
		else if (!strcmp(arg, "--all"))
			do_all = 1;
		else if (!strcmp(arg, "--verbose"))
			cb.verbose = 1;
		else if (!strcmp(arg, "--")) {
			i++;
			break;
		}
		else if (arg[0] == '-')
			usage(reflog_expire_usage);
		else
			break;
	}

	/*
	 * We can trust the commits and objects reachable from refs
	 * even in older repository.  We cannot trust what's reachable
	 * from reflog if the repository was pruned with older git.
	 */
	if (cb.stalefix) {
		init_revisions(&cb.revs, prefix);
		if (cb.verbose)
			printf("Marking reachable objects...");
		mark_reachable_objects(&cb.revs, 0, 0, NULL);
		if (cb.verbose)
			putchar('\n');
	}

	if (do_all) {
		struct collect_reflog_cb collected;
		int i;

		memset(&collected, 0, sizeof(collected));
		for_each_reflog(collect_reflog, &collected);
		for (i = 0; i < collected.nr; i++) {
			struct collected_reflog *e = collected.e[i];
			set_reflog_expiry_param(&cb, explicit_expiry, e->reflog);
			status |= expire_reflog(e->reflog, e->sha1, 0, &cb);
			free(e);
		}
		free(collected.e);
	}

	for (; i < argc; i++) {
		char *ref;
		unsigned char sha1[20];
		if (!dwim_log(argv[i], strlen(argv[i]), sha1, &ref)) {
			status |= error("%s points nowhere!", argv[i]);
			continue;
		}
		set_reflog_expiry_param(&cb, explicit_expiry, ref);
		status |= expire_reflog(ref, sha1, 0, &cb);
	}
	return status;
}

static int count_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
		const char *email, unsigned long timestamp, int tz,
		const char *message, void *cb_data)
{
	struct cmd_reflog_expire_cb *cb = cb_data;
	if (!cb->expire_total || timestamp < cb->expire_total)
		cb->recno++;
	return 0;
}

static int cmd_reflog_delete(int argc, const char **argv, const char *prefix)
{
	struct cmd_reflog_expire_cb cb;
	int i, status = 0;

	memset(&cb, 0, sizeof(cb));

	for (i = 1; i < argc; i++) {
		const char *arg = argv[i];
		if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
			cb.dry_run = 1;
		else if (!strcmp(arg, "--rewrite"))
			cb.rewrite = 1;
		else if (!strcmp(arg, "--updateref"))
			cb.updateref = 1;
		else if (!strcmp(arg, "--verbose"))
			cb.verbose = 1;
		else if (!strcmp(arg, "--")) {
			i++;
			break;
		}
		else if (arg[0] == '-')
			usage(reflog_delete_usage);
		else
			break;
	}

	if (argc - i < 1)
		return error("Nothing to delete?");

	for ( ; i < argc; i++) {
		const char *spec = strstr(argv[i], "@{");
		unsigned char sha1[20];
		char *ep, *ref;
		int recno;

		if (!spec) {
			status |= error("Not a reflog: %s", argv[i]);
			continue;
		}

		if (!dwim_log(argv[i], spec - argv[i], sha1, &ref)) {
			status |= error("no reflog for '%s'", argv[i]);
			continue;
		}

		recno = strtoul(spec + 2, &ep, 10);
		if (*ep == '}') {
			cb.recno = -recno;
			for_each_reflog_ent(ref, count_reflog_ent, &cb);
		} else {
			cb.expire_total = approxidate(spec + 2);
			for_each_reflog_ent(ref, count_reflog_ent, &cb);
			cb.expire_total = 0;
		}

		status |= expire_reflog(ref, sha1, 0, &cb);
		free(ref);
	}
	return status;
}

/*
 * main "reflog"
 */

static const char reflog_usage[] =
"git reflog [ show | expire | delete ]";

int cmd_reflog(int argc, const char **argv, const char *prefix)
{
	if (argc > 1 && !strcmp(argv[1], "-h"))
		usage(reflog_usage);

	/* With no command, we default to showing it. */
	if (argc < 2 || *argv[1] == '-')
		return cmd_log_reflog(argc, argv, prefix);

	if (!strcmp(argv[1], "show"))
		return cmd_log_reflog(argc - 1, argv + 1, prefix);

	if (!strcmp(argv[1], "expire"))
		return cmd_reflog_expire(argc - 1, argv + 1, prefix);

	if (!strcmp(argv[1], "delete"))
		return cmd_reflog_delete(argc - 1, argv + 1, prefix);

	return cmd_log_reflog(argc, argv, prefix);
}