From: Junio C Hamano <gitster@pobox.com>
Date: Sun, 9 May 2010 05:36:16 +0000 (-0700)
Subject: Merge branch 'jc/maint-reflog-expire-unreachable'
X-Git-Tag: v1.7.2-rc0~153
X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=a9eb30412942224c1494357f495b8b2a4b3d46b8;p=git.git

Merge branch 'jc/maint-reflog-expire-unreachable'

* jc/maint-reflog-expire-unreachable:
  reflog --expire-unreachable: avoid merge-base computation
---

a9eb30412942224c1494357f495b8b2a4b3d46b8
diff --cc builtin/reflog.c
index bd7880dc0,000000000..f73215686
mode 100644,000000..100644
--- a/builtin/reflog.c
+++ b/builtin/reflog.c
@@@ -1,717 -1,0 +1,733 @@@
 +#include "cache.h"
 +#include "builtin.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;
 +	const char *ref;
 +	struct commit *ref_commit;
++	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->buffer = NULL;
 +
 +	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;
 +}
 +
- static int unreachable(struct expire_reflog_cb *cb, struct commit *commit, unsigned char *sha1)
++/*
++ * 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)
 +{
- 	/*
- 	 * 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 (in_merge_bases(commit, &cb->ref_commit, 1))
- 		return 0;
- 
- 	/* We can't reach it - prune it. */
- 	return 1;
- }
++	struct commit *commit;
++	struct commit_list *pending;
++	unsigned long expire_limit = cb->mark_limit;
++	struct commit_list *leftover = NULL;
 +
- static void mark_reachable(struct commit *commit, unsigned long expire_limit)
- {
- 	/*
- 	 * We need to compute whether the commit on either side of a reflog
- 	 * entry is reachable from the tip of the ref for all entries.
- 	 * Mark commits that are reachable from the tip down to the
- 	 * time threshold first; we know a commit marked thusly is
- 	 * reachable from the tip without running in_merge_bases()
- 	 * at all.
- 	 */
- 	struct commit_list *pending = NULL;
++	for (pending = cb->mark_list; pending; pending = pending->next)
++		pending->item->object.flags &= ~REACHABLE;
 +
- 	commit_list_insert(commit, &pending);
++	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)
++		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->ref_commit)
 +			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 || cb->cmd->verbose)
 +		printf("%sprune %s", cb->newlog ? "" : "would ", message);
 +	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;
 +	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);
 +	if (!lock)
 +		return error("cannot lock ref '%s'", ref);
 +	log_file = git_pathdup("logs/%s", ref);
 +	if (!file_exists(log_file))
 +		goto finish;
 +	if (!cmd->dry_run) {
 +		newlog_path = git_pathdup("logs/%s.lock", ref);
 +		cb.newlog = fopen(newlog_path, "w");
 +	}
 +
 +	cb.ref_commit = lookup_commit_reference_gently(sha1, 1);
 +	cb.ref = ref;
 +	cb.cmd = cmd;
- 	if (cb.ref_commit)
- 		mark_reachable(cb.ref_commit, cmd->expire_total);
++	if (cb.ref_commit) {
++		cb.mark_list = NULL;
++		commit_list_insert(cb.ref_commit, &cb.mark_list);
++		cb.mark_limit = cmd->expire_total;
++		mark_reachable(&cb);
++	}
 +	for_each_reflog_ent(ref, expire_reflog_ent, &cb);
 +	if (cb.ref_commit)
 +		clear_commit_marks(cb.ref_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);
 +			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 (!strcmp(value, "never") || !strcmp(value, "false")) {
 +		*expire = 0;
 +		return 0;
 +	}
 +	*expire = approxidate(value);
 +	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 *lastdot = strrchr(var, '.');
 +	unsigned long expire;
 +	int slot;
 +	struct reflog_expire_cfg *ent;
 +
 +	if (!lastdot || prefixcmp(var, "gc."))
 +		return git_default_config(var, value, cb);
 +
 +	if (!strcmp(lastdot, ".reflogexpire")) {
 +		slot = EXPIRE_TOTAL;
 +		if (parse_expire_cfg_value(var, value, &expire))
 +			return -1;
 +	} else if (!strcmp(lastdot, ".reflogexpireunreachable")) {
 +		slot = EXPIRE_UNREACH;
 +		if (parse_expire_cfg_value(var, value, &expire))
 +			return -1;
 +	} else
 +		return git_default_config(var, value, cb);
 +
 +	if (lastdot == var + 2) {
 +		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(var + 3, lastdot - (var+3));
 +	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 (!fnmatch(ent->pattern, ref, 0)) {
 +			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 (!prefixcmp(arg, "--expire=")) {
 +			cb.expire_total = approxidate(arg + 9);
 +			explicit_expiry |= EXPIRE_TOTAL;
 +		}
 +		else if (!prefixcmp(arg, "--expire-unreachable=")) {
 +			cb.expire_unreachable = approxidate(arg + 21);
 +			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);
 +		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);
 +
 +	/* Not a recognized reflog command..*/
 +	usage(reflog_usage);
 +}