From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Fri, 22 Jan 2010 15:42:14 +0000 (-0800)
Subject: make "git pack-redundant" a built-in
X-Git-Tag: v1.7.0-rc0~32
X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=377d0276ca7446ce9fb2f6987b1e6b4ba9e7cf29;p=git.git

make "git pack-redundant" a built-in

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

diff --git a/Makefile b/Makefile
index 88e2f8fd4..33f987088 100644
--- a/Makefile
+++ b/Makefile
@@ -389,7 +389,6 @@ PROGRAMS += $(EXTRA_PROGRAMS)
 PROGRAMS += git-fast-import$X
 PROGRAMS += git-imap-send$X
 PROGRAMS += git-index-pack$X
-PROGRAMS += git-pack-redundant$X
 PROGRAMS += git-shell$X
 PROGRAMS += git-show-index$X
 PROGRAMS += git-upload-pack$X
@@ -673,6 +672,7 @@ BUILTIN_OBJS += builtin-mktree.o
 BUILTIN_OBJS += builtin-mv.o
 BUILTIN_OBJS += builtin-name-rev.o
 BUILTIN_OBJS += builtin-pack-objects.o
+BUILTIN_OBJS += builtin-pack-redundant.o
 BUILTIN_OBJS += builtin-pack-refs.o
 BUILTIN_OBJS += builtin-patch-id.o
 BUILTIN_OBJS += builtin-prune-packed.o
diff --git a/builtin-pack-redundant.c b/builtin-pack-redundant.c
new file mode 100644
index 000000000..41e1615a2
--- /dev/null
+++ b/builtin-pack-redundant.c
@@ -0,0 +1,696 @@
+/*
+*
+* Copyright 2005, Lukas Sandstrom <lukass@etek.chalmers.se>
+*
+* This file is licensed under the GPL v2.
+*
+*/
+
+#include "cache.h"
+#include "exec_cmd.h"
+
+#define BLKSIZE 512
+
+static const char pack_redundant_usage[] =
+"git pack-redundant [ --verbose ] [ --alt-odb ] < --all | <.pack filename> ...>";
+
+static int load_all_packs, verbose, alt_odb;
+
+struct llist_item {
+	struct llist_item *next;
+	const unsigned char *sha1;
+};
+static struct llist {
+	struct llist_item *front;
+	struct llist_item *back;
+	size_t size;
+} *all_objects; /* all objects which must be present in local packfiles */
+
+static struct pack_list {
+	struct pack_list *next;
+	struct packed_git *pack;
+	struct llist *unique_objects;
+	struct llist *all_objects;
+} *local_packs = NULL, *altodb_packs = NULL;
+
+struct pll {
+	struct pll *next;
+	struct pack_list *pl;
+};
+
+static struct llist_item *free_nodes;
+
+static inline void llist_item_put(struct llist_item *item)
+{
+	item->next = free_nodes;
+	free_nodes = item;
+}
+
+static inline struct llist_item *llist_item_get(void)
+{
+	struct llist_item *new;
+	if ( free_nodes ) {
+		new = free_nodes;
+		free_nodes = free_nodes->next;
+	} else {
+		int i = 1;
+		new = xmalloc(sizeof(struct llist_item) * BLKSIZE);
+		for (; i < BLKSIZE; i++)
+			llist_item_put(&new[i]);
+	}
+	return new;
+}
+
+static void llist_free(struct llist *list)
+{
+	while ((list->back = list->front)) {
+		list->front = list->front->next;
+		llist_item_put(list->back);
+	}
+	free(list);
+}
+
+static inline void llist_init(struct llist **list)
+{
+	*list = xmalloc(sizeof(struct llist));
+	(*list)->front = (*list)->back = NULL;
+	(*list)->size = 0;
+}
+
+static struct llist * llist_copy(struct llist *list)
+{
+	struct llist *ret;
+	struct llist_item *new, *old, *prev;
+
+	llist_init(&ret);
+
+	if ((ret->size = list->size) == 0)
+		return ret;
+
+	new = ret->front = llist_item_get();
+	new->sha1 = list->front->sha1;
+
+	old = list->front->next;
+	while (old) {
+		prev = new;
+		new = llist_item_get();
+		prev->next = new;
+		new->sha1 = old->sha1;
+		old = old->next;
+	}
+	new->next = NULL;
+	ret->back = new;
+
+	return ret;
+}
+
+static inline struct llist_item *llist_insert(struct llist *list,
+					      struct llist_item *after,
+					       const unsigned char *sha1)
+{
+	struct llist_item *new = llist_item_get();
+	new->sha1 = sha1;
+	new->next = NULL;
+
+	if (after != NULL) {
+		new->next = after->next;
+		after->next = new;
+		if (after == list->back)
+			list->back = new;
+	} else {/* insert in front */
+		if (list->size == 0)
+			list->back = new;
+		else
+			new->next = list->front;
+		list->front = new;
+	}
+	list->size++;
+	return new;
+}
+
+static inline struct llist_item *llist_insert_back(struct llist *list,
+						   const unsigned char *sha1)
+{
+	return llist_insert(list, list->back, sha1);
+}
+
+static inline struct llist_item *llist_insert_sorted_unique(struct llist *list,
+			const unsigned char *sha1, struct llist_item *hint)
+{
+	struct llist_item *prev = NULL, *l;
+
+	l = (hint == NULL) ? list->front : hint;
+	while (l) {
+		int cmp = hashcmp(l->sha1, sha1);
+		if (cmp > 0) { /* we insert before this entry */
+			return llist_insert(list, prev, sha1);
+		}
+		if (!cmp) { /* already exists */
+			return l;
+		}
+		prev = l;
+		l = l->next;
+	}
+	/* insert at the end */
+	return llist_insert_back(list, sha1);
+}
+
+/* returns a pointer to an item in front of sha1 */
+static inline struct llist_item * llist_sorted_remove(struct llist *list, const unsigned char *sha1, struct llist_item *hint)
+{
+	struct llist_item *prev, *l;
+
+redo_from_start:
+	l = (hint == NULL) ? list->front : hint;
+	prev = NULL;
+	while (l) {
+		int cmp = hashcmp(l->sha1, sha1);
+		if (cmp > 0) /* not in list, since sorted */
+			return prev;
+		if (!cmp) { /* found */
+			if (prev == NULL) {
+				if (hint != NULL && hint != list->front) {
+					/* we don't know the previous element */
+					hint = NULL;
+					goto redo_from_start;
+				}
+				list->front = l->next;
+			} else
+				prev->next = l->next;
+			if (l == list->back)
+				list->back = prev;
+			llist_item_put(l);
+			list->size--;
+			return prev;
+		}
+		prev = l;
+		l = l->next;
+	}
+	return prev;
+}
+
+/* computes A\B */
+static void llist_sorted_difference_inplace(struct llist *A,
+				     struct llist *B)
+{
+	struct llist_item *hint, *b;
+
+	hint = NULL;
+	b = B->front;
+
+	while (b) {
+		hint = llist_sorted_remove(A, b->sha1, hint);
+		b = b->next;
+	}
+}
+
+static inline struct pack_list * pack_list_insert(struct pack_list **pl,
+					   struct pack_list *entry)
+{
+	struct pack_list *p = xmalloc(sizeof(struct pack_list));
+	memcpy(p, entry, sizeof(struct pack_list));
+	p->next = *pl;
+	*pl = p;
+	return p;
+}
+
+static inline size_t pack_list_size(struct pack_list *pl)
+{
+	size_t ret = 0;
+	while (pl) {
+		ret++;
+		pl = pl->next;
+	}
+	return ret;
+}
+
+static struct pack_list * pack_list_difference(const struct pack_list *A,
+					       const struct pack_list *B)
+{
+	struct pack_list *ret;
+	const struct pack_list *pl;
+
+	if (A == NULL)
+		return NULL;
+
+	pl = B;
+	while (pl != NULL) {
+		if (A->pack == pl->pack)
+			return pack_list_difference(A->next, B);
+		pl = pl->next;
+	}
+	ret = xmalloc(sizeof(struct pack_list));
+	memcpy(ret, A, sizeof(struct pack_list));
+	ret->next = pack_list_difference(A->next, B);
+	return ret;
+}
+
+static void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
+{
+	unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
+	const unsigned char *p1_base, *p2_base;
+	struct llist_item *p1_hint = NULL, *p2_hint = NULL;
+
+	p1_base = p1->pack->index_data;
+	p2_base = p2->pack->index_data;
+	p1_base += 256 * 4 + ((p1->pack->index_version < 2) ? 4 : 8);
+	p2_base += 256 * 4 + ((p2->pack->index_version < 2) ? 4 : 8);
+	p1_step = (p1->pack->index_version < 2) ? 24 : 20;
+	p2_step = (p2->pack->index_version < 2) ? 24 : 20;
+
+	while (p1_off < p1->pack->num_objects * p1_step &&
+	       p2_off < p2->pack->num_objects * p2_step)
+	{
+		int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
+		/* cmp ~ p1 - p2 */
+		if (cmp == 0) {
+			p1_hint = llist_sorted_remove(p1->unique_objects,
+					p1_base + p1_off, p1_hint);
+			p2_hint = llist_sorted_remove(p2->unique_objects,
+					p1_base + p1_off, p2_hint);
+			p1_off += p1_step;
+			p2_off += p2_step;
+			continue;
+		}
+		if (cmp < 0) { /* p1 has the object, p2 doesn't */
+			p1_off += p1_step;
+		} else { /* p2 has the object, p1 doesn't */
+			p2_off += p2_step;
+		}
+	}
+}
+
+static void pll_free(struct pll *l)
+{
+	struct pll *old;
+	struct pack_list *opl;
+
+	while (l) {
+		old = l;
+		while (l->pl) {
+			opl = l->pl;
+			l->pl = opl->next;
+			free(opl);
+		}
+		l = l->next;
+		free(old);
+	}
+}
+
+/* all the permutations have to be free()d at the same time,
+ * since they refer to each other
+ */
+static struct pll * get_permutations(struct pack_list *list, int n)
+{
+	struct pll *subset, *ret = NULL, *new_pll = NULL, *pll;
+
+	if (list == NULL || pack_list_size(list) < n || n == 0)
+		return NULL;
+
+	if (n == 1) {
+		while (list) {
+			new_pll = xmalloc(sizeof(pll));
+			new_pll->pl = NULL;
+			pack_list_insert(&new_pll->pl, list);
+			new_pll->next = ret;
+			ret = new_pll;
+			list = list->next;
+		}
+		return ret;
+	}
+
+	while (list->next) {
+		subset = get_permutations(list->next, n - 1);
+		while (subset) {
+			new_pll = xmalloc(sizeof(pll));
+			new_pll->pl = subset->pl;
+			pack_list_insert(&new_pll->pl, list);
+			new_pll->next = ret;
+			ret = new_pll;
+			subset = subset->next;
+		}
+		list = list->next;
+	}
+	return ret;
+}
+
+static int is_superset(struct pack_list *pl, struct llist *list)
+{
+	struct llist *diff;
+
+	diff = llist_copy(list);
+
+	while (pl) {
+		llist_sorted_difference_inplace(diff, pl->all_objects);
+		if (diff->size == 0) { /* we're done */
+			llist_free(diff);
+			return 1;
+		}
+		pl = pl->next;
+	}
+	llist_free(diff);
+	return 0;
+}
+
+static size_t sizeof_union(struct packed_git *p1, struct packed_git *p2)
+{
+	size_t ret = 0;
+	unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
+	const unsigned char *p1_base, *p2_base;
+
+	p1_base = p1->index_data;
+	p2_base = p2->index_data;
+	p1_base += 256 * 4 + ((p1->index_version < 2) ? 4 : 8);
+	p2_base += 256 * 4 + ((p2->index_version < 2) ? 4 : 8);
+	p1_step = (p1->index_version < 2) ? 24 : 20;
+	p2_step = (p2->index_version < 2) ? 24 : 20;
+
+	while (p1_off < p1->num_objects * p1_step &&
+	       p2_off < p2->num_objects * p2_step)
+	{
+		int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
+		/* cmp ~ p1 - p2 */
+		if (cmp == 0) {
+			ret++;
+			p1_off += p1_step;
+			p2_off += p2_step;
+			continue;
+		}
+		if (cmp < 0) { /* p1 has the object, p2 doesn't */
+			p1_off += p1_step;
+		} else { /* p2 has the object, p1 doesn't */
+			p2_off += p2_step;
+		}
+	}
+	return ret;
+}
+
+/* another O(n^2) function ... */
+static size_t get_pack_redundancy(struct pack_list *pl)
+{
+	struct pack_list *subset;
+	size_t ret = 0;
+
+	if (pl == NULL)
+		return 0;
+
+	while ((subset = pl->next)) {
+		while (subset) {
+			ret += sizeof_union(pl->pack, subset->pack);
+			subset = subset->next;
+		}
+		pl = pl->next;
+	}
+	return ret;
+}
+
+static inline off_t pack_set_bytecount(struct pack_list *pl)
+{
+	off_t ret = 0;
+	while (pl) {
+		ret += pl->pack->pack_size;
+		ret += pl->pack->index_size;
+		pl = pl->next;
+	}
+	return ret;
+}
+
+static void minimize(struct pack_list **min)
+{
+	struct pack_list *pl, *unique = NULL,
+		*non_unique = NULL, *min_perm = NULL;
+	struct pll *perm, *perm_all, *perm_ok = NULL, *new_perm;
+	struct llist *missing;
+	off_t min_perm_size = 0, perm_size;
+	int n;
+
+	pl = local_packs;
+	while (pl) {
+		if (pl->unique_objects->size)
+			pack_list_insert(&unique, pl);
+		else
+			pack_list_insert(&non_unique, pl);
+		pl = pl->next;
+	}
+	/* find out which objects are missing from the set of unique packs */
+	missing = llist_copy(all_objects);
+	pl = unique;
+	while (pl) {
+		llist_sorted_difference_inplace(missing, pl->all_objects);
+		pl = pl->next;
+	}
+
+	/* return if there are no objects missing from the unique set */
+	if (missing->size == 0) {
+		*min = unique;
+		return;
+	}
+
+	/* find the permutations which contain all missing objects */
+	for (n = 1; n <= pack_list_size(non_unique) && !perm_ok; n++) {
+		perm_all = perm = get_permutations(non_unique, n);
+		while (perm) {
+			if (is_superset(perm->pl, missing)) {
+				new_perm = xmalloc(sizeof(struct pll));
+				memcpy(new_perm, perm, sizeof(struct pll));
+				new_perm->next = perm_ok;
+				perm_ok = new_perm;
+			}
+			perm = perm->next;
+		}
+		if (perm_ok)
+			break;
+		pll_free(perm_all);
+	}
+	if (perm_ok == NULL)
+		die("Internal error: No complete sets found!");
+
+	/* find the permutation with the smallest size */
+	perm = perm_ok;
+	while (perm) {
+		perm_size = pack_set_bytecount(perm->pl);
+		if (!min_perm_size || min_perm_size > perm_size) {
+			min_perm_size = perm_size;
+			min_perm = perm->pl;
+		}
+		perm = perm->next;
+	}
+	*min = min_perm;
+	/* add the unique packs to the list */
+	pl = unique;
+	while (pl) {
+		pack_list_insert(min, pl);
+		pl = pl->next;
+	}
+}
+
+static void load_all_objects(void)
+{
+	struct pack_list *pl = local_packs;
+	struct llist_item *hint, *l;
+
+	llist_init(&all_objects);
+
+	while (pl) {
+		hint = NULL;
+		l = pl->all_objects->front;
+		while (l) {
+			hint = llist_insert_sorted_unique(all_objects,
+							  l->sha1, hint);
+			l = l->next;
+		}
+		pl = pl->next;
+	}
+	/* remove objects present in remote packs */
+	pl = altodb_packs;
+	while (pl) {
+		llist_sorted_difference_inplace(all_objects, pl->all_objects);
+		pl = pl->next;
+	}
+}
+
+/* this scales like O(n^2) */
+static void cmp_local_packs(void)
+{
+	struct pack_list *subset, *pl = local_packs;
+
+	while ((subset = pl)) {
+		while ((subset = subset->next))
+			cmp_two_packs(pl, subset);
+		pl = pl->next;
+	}
+}
+
+static void scan_alt_odb_packs(void)
+{
+	struct pack_list *local, *alt;
+
+	alt = altodb_packs;
+	while (alt) {
+		local = local_packs;
+		while (local) {
+			llist_sorted_difference_inplace(local->unique_objects,
+							alt->all_objects);
+			local = local->next;
+		}
+		llist_sorted_difference_inplace(all_objects, alt->all_objects);
+		alt = alt->next;
+	}
+}
+
+static struct pack_list * add_pack(struct packed_git *p)
+{
+	struct pack_list l;
+	unsigned long off = 0, step;
+	const unsigned char *base;
+
+	if (!p->pack_local && !(alt_odb || verbose))
+		return NULL;
+
+	l.pack = p;
+	llist_init(&l.all_objects);
+
+	if (open_pack_index(p))
+		return NULL;
+
+	base = p->index_data;
+	base += 256 * 4 + ((p->index_version < 2) ? 4 : 8);
+	step = (p->index_version < 2) ? 24 : 20;
+	while (off < p->num_objects * step) {
+		llist_insert_back(l.all_objects, base + off);
+		off += step;
+	}
+	/* this list will be pruned in cmp_two_packs later */
+	l.unique_objects = llist_copy(l.all_objects);
+	if (p->pack_local)
+		return pack_list_insert(&local_packs, &l);
+	else
+		return pack_list_insert(&altodb_packs, &l);
+}
+
+static struct pack_list * add_pack_file(const char *filename)
+{
+	struct packed_git *p = packed_git;
+
+	if (strlen(filename) < 40)
+		die("Bad pack filename: %s", filename);
+
+	while (p) {
+		if (strstr(p->pack_name, filename))
+			return add_pack(p);
+		p = p->next;
+	}
+	die("Filename %s not found in packed_git", filename);
+}
+
+static void load_all(void)
+{
+	struct packed_git *p = packed_git;
+
+	while (p) {
+		add_pack(p);
+		p = p->next;
+	}
+}
+
+int cmd_pack_redundant(int argc, const char **argv, const char *prefix)
+{
+	int i;
+	struct pack_list *min, *red, *pl;
+	struct llist *ignore;
+	unsigned char *sha1;
+	char buf[42]; /* 40 byte sha1 + \n + \0 */
+
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage(pack_redundant_usage);
+
+	for (i = 1; i < argc; i++) {
+		const char *arg = argv[i];
+		if (!strcmp(arg, "--")) {
+			i++;
+			break;
+		}
+		if (!strcmp(arg, "--all")) {
+			load_all_packs = 1;
+			continue;
+		}
+		if (!strcmp(arg, "--verbose")) {
+			verbose = 1;
+			continue;
+		}
+		if (!strcmp(arg, "--alt-odb")) {
+			alt_odb = 1;
+			continue;
+		}
+		if (*arg == '-')
+			usage(pack_redundant_usage);
+		else
+			break;
+	}
+
+	prepare_packed_git();
+
+	if (load_all_packs)
+		load_all();
+	else
+		while (*(argv + i) != NULL)
+			add_pack_file(*(argv + i++));
+
+	if (local_packs == NULL)
+		die("Zero packs found!");
+
+	load_all_objects();
+
+	cmp_local_packs();
+	if (alt_odb)
+		scan_alt_odb_packs();
+
+	/* ignore objects given on stdin */
+	llist_init(&ignore);
+	if (!isatty(0)) {
+		while (fgets(buf, sizeof(buf), stdin)) {
+			sha1 = xmalloc(20);
+			if (get_sha1_hex(buf, sha1))
+				die("Bad sha1 on stdin: %s", buf);
+			llist_insert_sorted_unique(ignore, sha1, NULL);
+		}
+	}
+	llist_sorted_difference_inplace(all_objects, ignore);
+	pl = local_packs;
+	while (pl) {
+		llist_sorted_difference_inplace(pl->unique_objects, ignore);
+		pl = pl->next;
+	}
+
+	minimize(&min);
+
+	if (verbose) {
+		fprintf(stderr, "There are %lu packs available in alt-odbs.\n",
+			(unsigned long)pack_list_size(altodb_packs));
+		fprintf(stderr, "The smallest (bytewise) set of packs is:\n");
+		pl = min;
+		while (pl) {
+			fprintf(stderr, "\t%s\n", pl->pack->pack_name);
+			pl = pl->next;
+		}
+		fprintf(stderr, "containing %lu duplicate objects "
+				"with a total size of %lukb.\n",
+			(unsigned long)get_pack_redundancy(min),
+			(unsigned long)pack_set_bytecount(min)/1024);
+		fprintf(stderr, "A total of %lu unique objects were considered.\n",
+			(unsigned long)all_objects->size);
+		fprintf(stderr, "Redundant packs (with indexes):\n");
+	}
+	pl = red = pack_list_difference(local_packs, min);
+	while (pl) {
+		printf("%s\n%s\n",
+		       sha1_pack_index_name(pl->pack->sha1),
+		       pl->pack->pack_name);
+		pl = pl->next;
+	}
+	if (verbose)
+		fprintf(stderr, "%luMB of redundant packs in total.\n",
+			(unsigned long)pack_set_bytecount(red)/(1024*1024));
+
+	return 0;
+}
diff --git a/builtin.h b/builtin.h
index d4fec89a1..bd7f73748 100644
--- a/builtin.h
+++ b/builtin.h
@@ -78,6 +78,7 @@ extern int cmd_mktree(int argc, const char **argv, const char *prefix);
 extern int cmd_mv(int argc, const char **argv, const char *prefix);
 extern int cmd_name_rev(int argc, const char **argv, const char *prefix);
 extern int cmd_pack_objects(int argc, const char **argv, const char *prefix);
+extern int cmd_pack_redundant(int argc, const char **argv, const char *prefix);
 extern int cmd_patch_id(int argc, const char **argv, const char *prefix);
 extern int cmd_pickaxe(int argc, const char **argv, const char *prefix);
 extern int cmd_prune(int argc, const char **argv, const char *prefix);
diff --git a/git.c b/git.c
index 832bd2d53..6cc1eba29 100644
--- a/git.c
+++ b/git.c
@@ -343,6 +343,7 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
 		{ "name-rev", cmd_name_rev, RUN_SETUP },
 		{ "pack-objects", cmd_pack_objects, RUN_SETUP },
+		{ "pack-redundant", cmd_pack_redundant, RUN_SETUP },
 		{ "patch-id", cmd_patch_id },
 		{ "peek-remote", cmd_ls_remote },
 		{ "pickaxe", cmd_blame, RUN_SETUP },
diff --git a/pack-redundant.c b/pack-redundant.c
deleted file mode 100644
index 21c61dbbe..000000000
--- a/pack-redundant.c
+++ /dev/null
@@ -1,700 +0,0 @@
-/*
-*
-* Copyright 2005, Lukas Sandstrom <lukass@etek.chalmers.se>
-*
-* This file is licensed under the GPL v2.
-*
-*/
-
-#include "cache.h"
-#include "exec_cmd.h"
-
-#define BLKSIZE 512
-
-static const char pack_redundant_usage[] =
-"git pack-redundant [ --verbose ] [ --alt-odb ] < --all | <.pack filename> ...>";
-
-static int load_all_packs, verbose, alt_odb;
-
-struct llist_item {
-	struct llist_item *next;
-	const unsigned char *sha1;
-};
-static struct llist {
-	struct llist_item *front;
-	struct llist_item *back;
-	size_t size;
-} *all_objects; /* all objects which must be present in local packfiles */
-
-static struct pack_list {
-	struct pack_list *next;
-	struct packed_git *pack;
-	struct llist *unique_objects;
-	struct llist *all_objects;
-} *local_packs = NULL, *altodb_packs = NULL;
-
-struct pll {
-	struct pll *next;
-	struct pack_list *pl;
-};
-
-static struct llist_item *free_nodes;
-
-static inline void llist_item_put(struct llist_item *item)
-{
-	item->next = free_nodes;
-	free_nodes = item;
-}
-
-static inline struct llist_item *llist_item_get(void)
-{
-	struct llist_item *new;
-	if ( free_nodes ) {
-		new = free_nodes;
-		free_nodes = free_nodes->next;
-	} else {
-		int i = 1;
-		new = xmalloc(sizeof(struct llist_item) * BLKSIZE);
-		for (; i < BLKSIZE; i++)
-			llist_item_put(&new[i]);
-	}
-	return new;
-}
-
-static void llist_free(struct llist *list)
-{
-	while ((list->back = list->front)) {
-		list->front = list->front->next;
-		llist_item_put(list->back);
-	}
-	free(list);
-}
-
-static inline void llist_init(struct llist **list)
-{
-	*list = xmalloc(sizeof(struct llist));
-	(*list)->front = (*list)->back = NULL;
-	(*list)->size = 0;
-}
-
-static struct llist * llist_copy(struct llist *list)
-{
-	struct llist *ret;
-	struct llist_item *new, *old, *prev;
-
-	llist_init(&ret);
-
-	if ((ret->size = list->size) == 0)
-		return ret;
-
-	new = ret->front = llist_item_get();
-	new->sha1 = list->front->sha1;
-
-	old = list->front->next;
-	while (old) {
-		prev = new;
-		new = llist_item_get();
-		prev->next = new;
-		new->sha1 = old->sha1;
-		old = old->next;
-	}
-	new->next = NULL;
-	ret->back = new;
-
-	return ret;
-}
-
-static inline struct llist_item *llist_insert(struct llist *list,
-					      struct llist_item *after,
-					       const unsigned char *sha1)
-{
-	struct llist_item *new = llist_item_get();
-	new->sha1 = sha1;
-	new->next = NULL;
-
-	if (after != NULL) {
-		new->next = after->next;
-		after->next = new;
-		if (after == list->back)
-			list->back = new;
-	} else {/* insert in front */
-		if (list->size == 0)
-			list->back = new;
-		else
-			new->next = list->front;
-		list->front = new;
-	}
-	list->size++;
-	return new;
-}
-
-static inline struct llist_item *llist_insert_back(struct llist *list,
-						   const unsigned char *sha1)
-{
-	return llist_insert(list, list->back, sha1);
-}
-
-static inline struct llist_item *llist_insert_sorted_unique(struct llist *list,
-			const unsigned char *sha1, struct llist_item *hint)
-{
-	struct llist_item *prev = NULL, *l;
-
-	l = (hint == NULL) ? list->front : hint;
-	while (l) {
-		int cmp = hashcmp(l->sha1, sha1);
-		if (cmp > 0) { /* we insert before this entry */
-			return llist_insert(list, prev, sha1);
-		}
-		if (!cmp) { /* already exists */
-			return l;
-		}
-		prev = l;
-		l = l->next;
-	}
-	/* insert at the end */
-	return llist_insert_back(list, sha1);
-}
-
-/* returns a pointer to an item in front of sha1 */
-static inline struct llist_item * llist_sorted_remove(struct llist *list, const unsigned char *sha1, struct llist_item *hint)
-{
-	struct llist_item *prev, *l;
-
-redo_from_start:
-	l = (hint == NULL) ? list->front : hint;
-	prev = NULL;
-	while (l) {
-		int cmp = hashcmp(l->sha1, sha1);
-		if (cmp > 0) /* not in list, since sorted */
-			return prev;
-		if (!cmp) { /* found */
-			if (prev == NULL) {
-				if (hint != NULL && hint != list->front) {
-					/* we don't know the previous element */
-					hint = NULL;
-					goto redo_from_start;
-				}
-				list->front = l->next;
-			} else
-				prev->next = l->next;
-			if (l == list->back)
-				list->back = prev;
-			llist_item_put(l);
-			list->size--;
-			return prev;
-		}
-		prev = l;
-		l = l->next;
-	}
-	return prev;
-}
-
-/* computes A\B */
-static void llist_sorted_difference_inplace(struct llist *A,
-				     struct llist *B)
-{
-	struct llist_item *hint, *b;
-
-	hint = NULL;
-	b = B->front;
-
-	while (b) {
-		hint = llist_sorted_remove(A, b->sha1, hint);
-		b = b->next;
-	}
-}
-
-static inline struct pack_list * pack_list_insert(struct pack_list **pl,
-					   struct pack_list *entry)
-{
-	struct pack_list *p = xmalloc(sizeof(struct pack_list));
-	memcpy(p, entry, sizeof(struct pack_list));
-	p->next = *pl;
-	*pl = p;
-	return p;
-}
-
-static inline size_t pack_list_size(struct pack_list *pl)
-{
-	size_t ret = 0;
-	while (pl) {
-		ret++;
-		pl = pl->next;
-	}
-	return ret;
-}
-
-static struct pack_list * pack_list_difference(const struct pack_list *A,
-					       const struct pack_list *B)
-{
-	struct pack_list *ret;
-	const struct pack_list *pl;
-
-	if (A == NULL)
-		return NULL;
-
-	pl = B;
-	while (pl != NULL) {
-		if (A->pack == pl->pack)
-			return pack_list_difference(A->next, B);
-		pl = pl->next;
-	}
-	ret = xmalloc(sizeof(struct pack_list));
-	memcpy(ret, A, sizeof(struct pack_list));
-	ret->next = pack_list_difference(A->next, B);
-	return ret;
-}
-
-static void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
-{
-	unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
-	const unsigned char *p1_base, *p2_base;
-	struct llist_item *p1_hint = NULL, *p2_hint = NULL;
-
-	p1_base = p1->pack->index_data;
-	p2_base = p2->pack->index_data;
-	p1_base += 256 * 4 + ((p1->pack->index_version < 2) ? 4 : 8);
-	p2_base += 256 * 4 + ((p2->pack->index_version < 2) ? 4 : 8);
-	p1_step = (p1->pack->index_version < 2) ? 24 : 20;
-	p2_step = (p2->pack->index_version < 2) ? 24 : 20;
-
-	while (p1_off < p1->pack->num_objects * p1_step &&
-	       p2_off < p2->pack->num_objects * p2_step)
-	{
-		int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
-		/* cmp ~ p1 - p2 */
-		if (cmp == 0) {
-			p1_hint = llist_sorted_remove(p1->unique_objects,
-					p1_base + p1_off, p1_hint);
-			p2_hint = llist_sorted_remove(p2->unique_objects,
-					p1_base + p1_off, p2_hint);
-			p1_off += p1_step;
-			p2_off += p2_step;
-			continue;
-		}
-		if (cmp < 0) { /* p1 has the object, p2 doesn't */
-			p1_off += p1_step;
-		} else { /* p2 has the object, p1 doesn't */
-			p2_off += p2_step;
-		}
-	}
-}
-
-static void pll_free(struct pll *l)
-{
-	struct pll *old;
-	struct pack_list *opl;
-
-	while (l) {
-		old = l;
-		while (l->pl) {
-			opl = l->pl;
-			l->pl = opl->next;
-			free(opl);
-		}
-		l = l->next;
-		free(old);
-	}
-}
-
-/* all the permutations have to be free()d at the same time,
- * since they refer to each other
- */
-static struct pll * get_permutations(struct pack_list *list, int n)
-{
-	struct pll *subset, *ret = NULL, *new_pll = NULL, *pll;
-
-	if (list == NULL || pack_list_size(list) < n || n == 0)
-		return NULL;
-
-	if (n == 1) {
-		while (list) {
-			new_pll = xmalloc(sizeof(pll));
-			new_pll->pl = NULL;
-			pack_list_insert(&new_pll->pl, list);
-			new_pll->next = ret;
-			ret = new_pll;
-			list = list->next;
-		}
-		return ret;
-	}
-
-	while (list->next) {
-		subset = get_permutations(list->next, n - 1);
-		while (subset) {
-			new_pll = xmalloc(sizeof(pll));
-			new_pll->pl = subset->pl;
-			pack_list_insert(&new_pll->pl, list);
-			new_pll->next = ret;
-			ret = new_pll;
-			subset = subset->next;
-		}
-		list = list->next;
-	}
-	return ret;
-}
-
-static int is_superset(struct pack_list *pl, struct llist *list)
-{
-	struct llist *diff;
-
-	diff = llist_copy(list);
-
-	while (pl) {
-		llist_sorted_difference_inplace(diff, pl->all_objects);
-		if (diff->size == 0) { /* we're done */
-			llist_free(diff);
-			return 1;
-		}
-		pl = pl->next;
-	}
-	llist_free(diff);
-	return 0;
-}
-
-static size_t sizeof_union(struct packed_git *p1, struct packed_git *p2)
-{
-	size_t ret = 0;
-	unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
-	const unsigned char *p1_base, *p2_base;
-
-	p1_base = p1->index_data;
-	p2_base = p2->index_data;
-	p1_base += 256 * 4 + ((p1->index_version < 2) ? 4 : 8);
-	p2_base += 256 * 4 + ((p2->index_version < 2) ? 4 : 8);
-	p1_step = (p1->index_version < 2) ? 24 : 20;
-	p2_step = (p2->index_version < 2) ? 24 : 20;
-
-	while (p1_off < p1->num_objects * p1_step &&
-	       p2_off < p2->num_objects * p2_step)
-	{
-		int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
-		/* cmp ~ p1 - p2 */
-		if (cmp == 0) {
-			ret++;
-			p1_off += p1_step;
-			p2_off += p2_step;
-			continue;
-		}
-		if (cmp < 0) { /* p1 has the object, p2 doesn't */
-			p1_off += p1_step;
-		} else { /* p2 has the object, p1 doesn't */
-			p2_off += p2_step;
-		}
-	}
-	return ret;
-}
-
-/* another O(n^2) function ... */
-static size_t get_pack_redundancy(struct pack_list *pl)
-{
-	struct pack_list *subset;
-	size_t ret = 0;
-
-	if (pl == NULL)
-		return 0;
-
-	while ((subset = pl->next)) {
-		while (subset) {
-			ret += sizeof_union(pl->pack, subset->pack);
-			subset = subset->next;
-		}
-		pl = pl->next;
-	}
-	return ret;
-}
-
-static inline off_t pack_set_bytecount(struct pack_list *pl)
-{
-	off_t ret = 0;
-	while (pl) {
-		ret += pl->pack->pack_size;
-		ret += pl->pack->index_size;
-		pl = pl->next;
-	}
-	return ret;
-}
-
-static void minimize(struct pack_list **min)
-{
-	struct pack_list *pl, *unique = NULL,
-		*non_unique = NULL, *min_perm = NULL;
-	struct pll *perm, *perm_all, *perm_ok = NULL, *new_perm;
-	struct llist *missing;
-	off_t min_perm_size = 0, perm_size;
-	int n;
-
-	pl = local_packs;
-	while (pl) {
-		if (pl->unique_objects->size)
-			pack_list_insert(&unique, pl);
-		else
-			pack_list_insert(&non_unique, pl);
-		pl = pl->next;
-	}
-	/* find out which objects are missing from the set of unique packs */
-	missing = llist_copy(all_objects);
-	pl = unique;
-	while (pl) {
-		llist_sorted_difference_inplace(missing, pl->all_objects);
-		pl = pl->next;
-	}
-
-	/* return if there are no objects missing from the unique set */
-	if (missing->size == 0) {
-		*min = unique;
-		return;
-	}
-
-	/* find the permutations which contain all missing objects */
-	for (n = 1; n <= pack_list_size(non_unique) && !perm_ok; n++) {
-		perm_all = perm = get_permutations(non_unique, n);
-		while (perm) {
-			if (is_superset(perm->pl, missing)) {
-				new_perm = xmalloc(sizeof(struct pll));
-				memcpy(new_perm, perm, sizeof(struct pll));
-				new_perm->next = perm_ok;
-				perm_ok = new_perm;
-			}
-			perm = perm->next;
-		}
-		if (perm_ok)
-			break;
-		pll_free(perm_all);
-	}
-	if (perm_ok == NULL)
-		die("Internal error: No complete sets found!");
-
-	/* find the permutation with the smallest size */
-	perm = perm_ok;
-	while (perm) {
-		perm_size = pack_set_bytecount(perm->pl);
-		if (!min_perm_size || min_perm_size > perm_size) {
-			min_perm_size = perm_size;
-			min_perm = perm->pl;
-		}
-		perm = perm->next;
-	}
-	*min = min_perm;
-	/* add the unique packs to the list */
-	pl = unique;
-	while (pl) {
-		pack_list_insert(min, pl);
-		pl = pl->next;
-	}
-}
-
-static void load_all_objects(void)
-{
-	struct pack_list *pl = local_packs;
-	struct llist_item *hint, *l;
-
-	llist_init(&all_objects);
-
-	while (pl) {
-		hint = NULL;
-		l = pl->all_objects->front;
-		while (l) {
-			hint = llist_insert_sorted_unique(all_objects,
-							  l->sha1, hint);
-			l = l->next;
-		}
-		pl = pl->next;
-	}
-	/* remove objects present in remote packs */
-	pl = altodb_packs;
-	while (pl) {
-		llist_sorted_difference_inplace(all_objects, pl->all_objects);
-		pl = pl->next;
-	}
-}
-
-/* this scales like O(n^2) */
-static void cmp_local_packs(void)
-{
-	struct pack_list *subset, *pl = local_packs;
-
-	while ((subset = pl)) {
-		while ((subset = subset->next))
-			cmp_two_packs(pl, subset);
-		pl = pl->next;
-	}
-}
-
-static void scan_alt_odb_packs(void)
-{
-	struct pack_list *local, *alt;
-
-	alt = altodb_packs;
-	while (alt) {
-		local = local_packs;
-		while (local) {
-			llist_sorted_difference_inplace(local->unique_objects,
-							alt->all_objects);
-			local = local->next;
-		}
-		llist_sorted_difference_inplace(all_objects, alt->all_objects);
-		alt = alt->next;
-	}
-}
-
-static struct pack_list * add_pack(struct packed_git *p)
-{
-	struct pack_list l;
-	unsigned long off = 0, step;
-	const unsigned char *base;
-
-	if (!p->pack_local && !(alt_odb || verbose))
-		return NULL;
-
-	l.pack = p;
-	llist_init(&l.all_objects);
-
-	if (open_pack_index(p))
-		return NULL;
-
-	base = p->index_data;
-	base += 256 * 4 + ((p->index_version < 2) ? 4 : 8);
-	step = (p->index_version < 2) ? 24 : 20;
-	while (off < p->num_objects * step) {
-		llist_insert_back(l.all_objects, base + off);
-		off += step;
-	}
-	/* this list will be pruned in cmp_two_packs later */
-	l.unique_objects = llist_copy(l.all_objects);
-	if (p->pack_local)
-		return pack_list_insert(&local_packs, &l);
-	else
-		return pack_list_insert(&altodb_packs, &l);
-}
-
-static struct pack_list * add_pack_file(char *filename)
-{
-	struct packed_git *p = packed_git;
-
-	if (strlen(filename) < 40)
-		die("Bad pack filename: %s", filename);
-
-	while (p) {
-		if (strstr(p->pack_name, filename))
-			return add_pack(p);
-		p = p->next;
-	}
-	die("Filename %s not found in packed_git", filename);
-}
-
-static void load_all(void)
-{
-	struct packed_git *p = packed_git;
-
-	while (p) {
-		add_pack(p);
-		p = p->next;
-	}
-}
-
-int main(int argc, char **argv)
-{
-	int i;
-	struct pack_list *min, *red, *pl;
-	struct llist *ignore;
-	unsigned char *sha1;
-	char buf[42]; /* 40 byte sha1 + \n + \0 */
-
-	git_extract_argv0_path(argv[0]);
-
-	if (argc == 2 && !strcmp(argv[1], "-h"))
-		usage(pack_redundant_usage);
-
-	setup_git_directory();
-
-	for (i = 1; i < argc; i++) {
-		const char *arg = argv[i];
-		if (!strcmp(arg, "--")) {
-			i++;
-			break;
-		}
-		if (!strcmp(arg, "--all")) {
-			load_all_packs = 1;
-			continue;
-		}
-		if (!strcmp(arg, "--verbose")) {
-			verbose = 1;
-			continue;
-		}
-		if (!strcmp(arg, "--alt-odb")) {
-			alt_odb = 1;
-			continue;
-		}
-		if (*arg == '-')
-			usage(pack_redundant_usage);
-		else
-			break;
-	}
-
-	prepare_packed_git();
-
-	if (load_all_packs)
-		load_all();
-	else
-		while (*(argv + i) != NULL)
-			add_pack_file(*(argv + i++));
-
-	if (local_packs == NULL)
-		die("Zero packs found!");
-
-	load_all_objects();
-
-	cmp_local_packs();
-	if (alt_odb)
-		scan_alt_odb_packs();
-
-	/* ignore objects given on stdin */
-	llist_init(&ignore);
-	if (!isatty(0)) {
-		while (fgets(buf, sizeof(buf), stdin)) {
-			sha1 = xmalloc(20);
-			if (get_sha1_hex(buf, sha1))
-				die("Bad sha1 on stdin: %s", buf);
-			llist_insert_sorted_unique(ignore, sha1, NULL);
-		}
-	}
-	llist_sorted_difference_inplace(all_objects, ignore);
-	pl = local_packs;
-	while (pl) {
-		llist_sorted_difference_inplace(pl->unique_objects, ignore);
-		pl = pl->next;
-	}
-
-	minimize(&min);
-
-	if (verbose) {
-		fprintf(stderr, "There are %lu packs available in alt-odbs.\n",
-			(unsigned long)pack_list_size(altodb_packs));
-		fprintf(stderr, "The smallest (bytewise) set of packs is:\n");
-		pl = min;
-		while (pl) {
-			fprintf(stderr, "\t%s\n", pl->pack->pack_name);
-			pl = pl->next;
-		}
-		fprintf(stderr, "containing %lu duplicate objects "
-				"with a total size of %lukb.\n",
-			(unsigned long)get_pack_redundancy(min),
-			(unsigned long)pack_set_bytecount(min)/1024);
-		fprintf(stderr, "A total of %lu unique objects were considered.\n",
-			(unsigned long)all_objects->size);
-		fprintf(stderr, "Redundant packs (with indexes):\n");
-	}
-	pl = red = pack_list_difference(local_packs, min);
-	while (pl) {
-		printf("%s\n%s\n",
-		       sha1_pack_index_name(pl->pack->sha1),
-		       pl->pack->pack_name);
-		pl = pl->next;
-	}
-	if (verbose)
-		fprintf(stderr, "%luMB of redundant packs in total.\n",
-			(unsigned long)pack_set_bytecount(red)/(1024*1024));
-
-	return 0;
-}