[thirdparty/git.git] / pack-redundant.c

/*
*
* 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]);

	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;
}
Commit	Line	Data
c283ab21 LS	1	/*
	2	*
	3	* Copyright 2005, Lukas Sandstrom <lukass@etek.chalmers.se>
	4	*
	5	* This file is licensed under the GPL v2.
	6	*
	7	*/
	8
	9	#include "cache.h"
2fb3f6db	10	#include "exec_cmd.h"
c283ab21	11
6d016c9c LS	12	#define BLKSIZE 512
6d016c9c LS	13
9bc0f32c	14	static const char pack_redundant_usage[] =
1b1dd23f	15	"git pack-redundant [ --verbose ] [ --alt-odb ] < --all \| <.pack filename> ...>";
c283ab21	16
96f1e58f	17	static int load_all_packs, verbose, alt_odb;
c283ab21 LS	18
	19	struct llist_item {
	20	struct llist_item *next;
42873078	21	const unsigned char *sha1;
c283ab21	22	};
bd22c904	23	static struct llist {
c283ab21 LS	24	struct llist_item *front;
	25	struct llist_item *back;
	26	size_t size;
1c3039e8	27	} all_objects; / all objects which must be present in local packfiles */
c283ab21	28
bd22c904	29	static struct pack_list {
c283ab21 LS	30	struct pack_list *next;
	31	struct packed_git *pack;
	32	struct llist *unique_objects;
	33	struct llist *all_objects;
1c3039e8	34	} local_packs = NULL, altodb_packs = NULL;
c283ab21 LS	35
	36	struct pll {
	37	struct pll *next;
	38	struct pack_list *pl;
	39	};
	40
96f1e58f	41	static struct llist_item *free_nodes;
60435f68	42
6d016c9c LS	43	static inline void llist_item_put(struct llist_item *item)
	44	{
	45	item->next = free_nodes;
	46	free_nodes = item;
	47	}
	48
962554c6	49	static inline struct llist_item *llist_item_get(void)
60435f68 AR	50	{
	51	struct llist_item *new;
	52	if ( free_nodes ) {
	53	new = free_nodes;
	54	free_nodes = free_nodes->next;
6d016c9c LS	55	} else {
	56	int i = 1;
	57	new = xmalloc(sizeof(struct llist_item) * BLKSIZE);
	58	for(;i < BLKSIZE; i++) {
	59	llist_item_put(&new[i]);
	60	}
	61	}
60435f68 AR	62	return new;
	63	}
	64
60435f68	65	static void llist_free(struct llist *list)
c283ab21 LS	66	{
	67	while((list->back = list->front)) {
	68	list->front = list->front->next;
60435f68	69	llist_item_put(list->back);
c283ab21 LS	70	}
	71	free(list);
	72	}
	73
bd22c904	74	static inline void llist_init(struct llist **list)
c283ab21 LS	75	{
	76	*list = xmalloc(sizeof(struct llist));
	77	(list)->front = (list)->back = NULL;
	78	(*list)->size = 0;
	79	}
	80
bd22c904	81	static struct llist * llist_copy(struct llist *list)
c283ab21 LS	82	{
	83	struct llist *ret;
	84	struct llist_item new, old, *prev;
a6080a0a	85
c283ab21 LS	86	llist_init(&ret);
	87
	88	if ((ret->size = list->size) == 0)
	89	return ret;
	90
60435f68	91	new = ret->front = llist_item_get();
c283ab21 LS	92	new->sha1 = list->front->sha1;
	93
	94	old = list->front->next;
	95	while (old) {
	96	prev = new;
60435f68	97	new = llist_item_get();
c283ab21 LS	98	prev->next = new;
	99	new->sha1 = old->sha1;
	100	old = old->next;
	101	}
	102	new->next = NULL;
	103	ret->back = new;
a6080a0a	104
c283ab21 LS	105	return ret;
	106	}
	107
42873078 NP	108	static inline struct llist_item llist_insert(struct llist list,
	109	struct llist_item *after,
	110	const unsigned char *sha1)
c283ab21	111	{
60435f68	112	struct llist_item *new = llist_item_get();
c283ab21 LS	113	new->sha1 = sha1;
	114	new->next = NULL;
	115
	116	if (after != NULL) {
	117	new->next = after->next;
	118	after->next = new;
	119	if (after == list->back)
	120	list->back = new;
	121	} else {/* insert in front */
	122	if (list->size == 0)
	123	list->back = new;
	124	else
	125	new->next = list->front;
	126	list->front = new;
	127	}
	128	list->size++;
	129	return new;
	130	}
	131
42873078 NP	132	static inline struct llist_item llist_insert_back(struct llist list,
42873078 NP	133	const unsigned char *sha1)
c283ab21 LS	134	{
	135	return llist_insert(list, list->back, sha1);
	136	}
	137
42873078 NP	138	static inline struct llist_item llist_insert_sorted_unique(struct llist list,
42873078 NP	139	const unsigned char sha1, struct llist_item hint)
c283ab21 LS	140	{
	141	struct llist_item prev = NULL, l;
	142
	143	l = (hint == NULL) ? list->front : hint;
	144	while (l) {
a89fccd2	145	int cmp = hashcmp(l->sha1, sha1);
c283ab21 LS	146	if (cmp > 0) { /* we insert before this entry */
	147	return llist_insert(list, prev, sha1);
	148	}
	149	if(!cmp) { /* already exists */
	150	return l;
	151	}
	152	prev = l;
	153	l = l->next;
	154	}
	155	/* insert at the end */
	156	return llist_insert_back(list, sha1);
	157	}
	158
c283ab21	159	/* returns a pointer to an item in front of sha1 */
b99a394c	160	static inline struct llist_item * llist_sorted_remove(struct llist list, const unsigned char sha1, struct llist_item *hint)
c283ab21 LS	161	{
	162	struct llist_item prev, l;
	163
	164	redo_from_start:
	165	l = (hint == NULL) ? list->front : hint;
	166	prev = NULL;
	167	while (l) {
a89fccd2	168	int cmp = hashcmp(l->sha1, sha1);
c283ab21 LS	169	if (cmp > 0) /* not in list, since sorted */
	170	return prev;
	171	if(!cmp) { /* found */
	172	if (prev == NULL) {
	173	if (hint != NULL && hint != list->front) {
	174	/* we don't know the previous element */
	175	hint = NULL;
	176	goto redo_from_start;
	177	}
	178	list->front = l->next;
	179	} else
	180	prev->next = l->next;
	181	if (l == list->back)
	182	list->back = prev;
60435f68	183	llist_item_put(l);
c283ab21 LS	184	list->size--;
	185	return prev;
	186	}
	187	prev = l;
	188	l = l->next;
	189	}
	190	return prev;
	191	}
	192
1a41e743	193	/* computes A\B */
bd22c904	194	static void llist_sorted_difference_inplace(struct llist *A,
1a41e743 LS	195	struct llist *B)
	196	{
	197	struct llist_item hint, b;
	198
	199	hint = NULL;
	200	b = B->front;
	201
	202	while (b) {
	203	hint = llist_sorted_remove(A, b->sha1, hint);
	204	b = b->next;
	205	}
	206	}
	207
bd22c904	208	static inline struct pack_list * pack_list_insert(struct pack_list **pl,
c283ab21 LS	209	struct pack_list *entry)
	210	{
	211	struct pack_list *p = xmalloc(sizeof(struct pack_list));
	212	memcpy(p, entry, sizeof(struct pack_list));
	213	p->next = *pl;
	214	*pl = p;
	215	return p;
	216	}
	217
bd22c904	218	static inline size_t pack_list_size(struct pack_list *pl)
1c3039e8 LS	219	{
	220	size_t ret = 0;
	221	while(pl) {
	222	ret++;
	223	pl = pl->next;
	224	}
	225	return ret;
	226	}
	227
d1ab1577 AR	228	static struct pack_list * pack_list_difference(const struct pack_list *A,
d1ab1577 AR	229	const struct pack_list *B)
c283ab21	230	{
d1ab1577 AR	231	struct pack_list *ret;
d1ab1577 AR	232	const struct pack_list *pl;
c283ab21 LS	233
	234	if (A == NULL)
	235	return NULL;
	236
	237	pl = B;
	238	while (pl != NULL) {
	239	if (A->pack == pl->pack)
	240	return pack_list_difference(A->next, B);
	241	pl = pl->next;
	242	}
	243	ret = xmalloc(sizeof(struct pack_list));
	244	memcpy(ret, A, sizeof(struct pack_list));
	245	ret->next = pack_list_difference(A->next, B);
	246	return ret;
	247	}
	248
bd22c904	249	static void cmp_two_packs(struct pack_list p1, struct pack_list p2)
c283ab21	250	{
8c681e07	251	unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
42873078	252	const unsigned char p1_base, p2_base;
c283ab21	253	struct llist_item p1_hint = NULL, p2_hint = NULL;
1d7f171c	254
42873078 NP	255	p1_base = p1->pack->index_data;
42873078 NP	256	p2_base = p2->pack->index_data;
8c681e07 NP	257	p1_base += 256 * 4 + ((p1->pack->index_version < 2) ? 4 : 8);
	258	p2_base += 256 * 4 + ((p2->pack->index_version < 2) ? 4 : 8);
	259	p1_step = (p1->pack->index_version < 2) ? 24 : 20;
	260	p2_step = (p2->pack->index_version < 2) ? 24 : 20;
c283ab21	261
8c681e07 NP	262	while (p1_off < p1->pack->num_objects * p1_step &&
8c681e07 NP	263	p2_off < p2->pack->num_objects * p2_step)
c283ab21	264	{
a89fccd2	265	int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
c283ab21 LS	266	/* cmp ~ p1 - p2 */
	267	if (cmp == 0) {
	268	p1_hint = llist_sorted_remove(p1->unique_objects,
	269	p1_base + p1_off, p1_hint);
	270	p2_hint = llist_sorted_remove(p2->unique_objects,
	271	p1_base + p1_off, p2_hint);
8c681e07 NP	272	p1_off += p1_step;
8c681e07 NP	273	p2_off += p2_step;
c283ab21 LS	274	continue;
	275	}
	276	if (cmp < 0) { /* p1 has the object, p2 doesn't */
8c681e07	277	p1_off += p1_step;
c283ab21	278	} else { /* p2 has the object, p1 doesn't */
8c681e07	279	p2_off += p2_step;
c283ab21 LS	280	}
	281	}
	282	}
	283
962554c6	284	static void pll_free(struct pll *l)
751a71e2	285	{
6d016c9c LS	286	struct pll *old;
	287	struct pack_list *opl;
	288
	289	while (l) {
	290	old = l;
	291	while (l->pl) {
	292	opl = l->pl;
	293	l->pl = opl->next;
	294	free(opl);
751a71e2	295	}
6d016c9c LS	296	l = l->next;
6d016c9c LS	297	free(old);
751a71e2	298	}
751a71e2 LS	299	}
751a71e2 LS	300
c283ab21 LS	301	/* all the permutations have to be free()d at the same time,
	302	* since they refer to each other
	303	*/
6d016c9c	304	static struct pll * get_permutations(struct pack_list *list, int n)
c283ab21	305	{
6d016c9c LS	306	struct pll subset, ret = NULL, new_pll = NULL, pll;
	307
	308	if (list == NULL \|\| pack_list_size(list) < n \|\| n == 0)
c283ab21 LS	309	return NULL;
c283ab21 LS	310
6d016c9c LS	311	if (n == 1) {
	312	while (list) {
	313	new_pll = xmalloc(sizeof(pll));
	314	new_pll->pl = NULL;
	315	pack_list_insert(&new_pll->pl, list);
	316	new_pll->next = ret;
	317	ret = new_pll;
	318	list = list->next;
	319	}
	320	return ret;
c283ab21 LS	321	}
c283ab21 LS	322
6d016c9c LS	323	while (list->next) {
	324	subset = get_permutations(list->next, n - 1);
	325	while (subset) {
	326	new_pll = xmalloc(sizeof(pll));
	327	new_pll->pl = subset->pl;
	328	pack_list_insert(&new_pll->pl, list);
	329	new_pll->next = ret;
	330	ret = new_pll;
	331	subset = subset->next;
751a71e2	332	}
6d016c9c	333	list = list->next;
c283ab21	334	}
6d016c9c	335	return ret;
c283ab21 LS	336	}
c283ab21 LS	337
bd22c904	338	static int is_superset(struct pack_list pl, struct llist list)
c283ab21	339	{
1c3039e8	340	struct llist *diff;
c283ab21 LS	341
	342	diff = llist_copy(list);
	343
	344	while (pl) {
d1ab1577	345	llist_sorted_difference_inplace(diff, pl->all_objects);
c283ab21 LS	346	if (diff->size == 0) { /* we're done */
	347	llist_free(diff);
	348	return 1;
	349	}
	350	pl = pl->next;
	351	}
	352	llist_free(diff);
	353	return 0;
	354	}
	355
bd22c904	356	static size_t sizeof_union(struct packed_git p1, struct packed_git p2)
c283ab21 LS	357	{
c283ab21 LS	358	size_t ret = 0;
8c681e07	359	unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
42873078	360	const unsigned char p1_base, p2_base;
c283ab21	361
42873078 NP	362	p1_base = p1->index_data;
42873078 NP	363	p2_base = p2->index_data;
8c681e07 NP	364	p1_base += 256 * 4 + ((p1->index_version < 2) ? 4 : 8);
	365	p2_base += 256 * 4 + ((p2->index_version < 2) ? 4 : 8);
	366	p1_step = (p1->index_version < 2) ? 24 : 20;
	367	p2_step = (p2->index_version < 2) ? 24 : 20;
c283ab21	368
8c681e07 NP	369	while (p1_off < p1->num_objects * p1_step &&
8c681e07 NP	370	p2_off < p2->num_objects * p2_step)
c283ab21	371	{
a89fccd2	372	int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
c283ab21 LS	373	/* cmp ~ p1 - p2 */
	374	if (cmp == 0) {
	375	ret++;
8c681e07 NP	376	p1_off += p1_step;
8c681e07 NP	377	p2_off += p2_step;
c283ab21 LS	378	continue;
	379	}
	380	if (cmp < 0) { /* p1 has the object, p2 doesn't */
8c681e07	381	p1_off += p1_step;
c283ab21	382	} else { /* p2 has the object, p1 doesn't */
8c681e07	383	p2_off += p2_step;
c283ab21 LS	384	}
	385	}
	386	return ret;
	387	}
	388
	389	/* another O(n^2) function ... */
bd22c904	390	static size_t get_pack_redundancy(struct pack_list *pl)
c283ab21 LS	391	{
c283ab21 LS	392	struct pack_list *subset;
bd22c904	393	size_t ret = 0;
1c3039e8 LS	394
	395	if (pl == NULL)
	396	return 0;
	397
c283ab21 LS	398	while ((subset = pl->next)) {
	399	while(subset) {
	400	ret += sizeof_union(pl->pack, subset->pack);
	401	subset = subset->next;
	402	}
	403	pl = pl->next;
	404	}
	405	return ret;
	406	}
	407
c4001d92	408	static inline off_t pack_set_bytecount(struct pack_list *pl)
c283ab21	409	{
c4001d92	410	off_t ret = 0;
c283ab21 LS	411	while (pl) {
	412	ret += pl->pack->pack_size;
	413	ret += pl->pack->index_size;
	414	pl = pl->next;
	415	}
	416	return ret;
	417	}
	418
bd22c904	419	static void minimize(struct pack_list **min)
c283ab21 LS	420	{
	421	struct pack_list pl, unique = NULL,
	422	non_unique = NULL, min_perm = NULL;
	423	struct pll perm, perm_all, perm_ok = NULL, new_perm;
1c3039e8	424	struct llist *missing;
c4001d92	425	off_t min_perm_size = 0, perm_size;
6d016c9c	426	int n;
c283ab21	427
1c3039e8	428	pl = local_packs;
c283ab21 LS	429	while (pl) {
	430	if(pl->unique_objects->size)
	431	pack_list_insert(&unique, pl);
	432	else
	433	pack_list_insert(&non_unique, pl);
	434	pl = pl->next;
	435	}
	436	/* find out which objects are missing from the set of unique packs */
	437	missing = llist_copy(all_objects);
	438	pl = unique;
	439	while (pl) {
6d016c9c	440	llist_sorted_difference_inplace(missing, pl->all_objects);
c283ab21 LS	441	pl = pl->next;
	442	}
	443
1c3039e8	444	/* return if there are no objects missing from the unique set */
c283ab21 LS	445	if (missing->size == 0) {
	446	*min = unique;
	447	return;
	448	}
	449
	450	/* find the permutations which contain all missing objects */
6d016c9c LS	451	for (n = 1; n <= pack_list_size(non_unique) && !perm_ok; n++) {
	452	perm_all = perm = get_permutations(non_unique, n);
	453	while (perm) {
	454	if (is_superset(perm->pl, missing)) {
	455	new_perm = xmalloc(sizeof(struct pll));
	456	memcpy(new_perm, perm, sizeof(struct pll));
	457	new_perm->next = perm_ok;
	458	perm_ok = new_perm;
	459	}
	460	perm = perm->next;
c283ab21	461	}
6d016c9c LS	462	if (perm_ok)
	463	break;
	464	pll_free(perm_all);
c283ab21	465	}
c283ab21	466	if (perm_ok == NULL)
d7530708	467	die("Internal error: No complete sets found!");
c283ab21 LS	468
	469	/* find the permutation with the smallest size */
	470	perm = perm_ok;
	471	while (perm) {
	472	perm_size = pack_set_bytecount(perm->pl);
c4001d92	473	if (!min_perm_size \|\| min_perm_size > perm_size) {
c283ab21 LS	474	min_perm_size = perm_size;
	475	min_perm = perm->pl;
	476	}
	477	perm = perm->next;
	478	}
	479	*min = min_perm;
	480	/* add the unique packs to the list */
	481	pl = unique;
	482	while(pl) {
	483	pack_list_insert(min, pl);
	484	pl = pl->next;
	485	}
	486	}
	487
bd22c904	488	static void load_all_objects(void)
c283ab21	489	{
1c3039e8	490	struct pack_list *pl = local_packs;
c283ab21	491	struct llist_item hint, l;
c283ab21 LS	492
	493	llist_init(&all_objects);
	494
	495	while (pl) {
c283ab21 LS	496	hint = NULL;
	497	l = pl->all_objects->front;
	498	while (l) {
	499	hint = llist_insert_sorted_unique(all_objects,
	500	l->sha1, hint);
	501	l = l->next;
	502	}
	503	pl = pl->next;
	504	}
1c3039e8 LS	505	/* remove objects present in remote packs */
	506	pl = altodb_packs;
	507	while (pl) {
	508	llist_sorted_difference_inplace(all_objects, pl->all_objects);
	509	pl = pl->next;
	510	}
c283ab21 LS	511	}
	512
	513	/* this scales like O(n^2) */
bd22c904	514	static void cmp_local_packs(void)
c283ab21	515	{
1c3039e8	516	struct pack_list subset, pl = local_packs;
c283ab21	517
1c3039e8	518	while ((subset = pl)) {
c283ab21	519	while((subset = subset->next))
1c3039e8 LS	520	cmp_two_packs(pl, subset);
	521	pl = pl->next;
	522	}
06a45c8c	523	}
1c3039e8	524
bd22c904	525	static void scan_alt_odb_packs(void)
06a45c8c LS	526	{
	527	struct pack_list local, alt;
	528
	529	alt = altodb_packs;
	530	while (alt) {
	531	local = local_packs;
	532	while (local) {
	533	llist_sorted_difference_inplace(local->unique_objects,
	534	alt->all_objects);
	535	local = local->next;
1c3039e8	536	}
6d016c9c	537	llist_sorted_difference_inplace(all_objects, alt->all_objects);
06a45c8c	538	alt = alt->next;
c283ab21 LS	539	}
	540	}
	541
bd22c904	542	static struct pack_list * add_pack(struct packed_git *p)
c283ab21 LS	543	{
c283ab21 LS	544	struct pack_list l;
8c681e07	545	unsigned long off = 0, step;
42873078	546	const unsigned char *base;
c283ab21	547
06a45c8c LS	548	if (!p->pack_local && !(alt_odb \|\| verbose))
	549	return NULL;
	550
c283ab21 LS	551	l.pack = p;
	552	llist_init(&l.all_objects);
	553
eaa86770	554	if (open_pack_index(p))
d079837e SP	555	return NULL;
d079837e SP	556
42873078	557	base = p->index_data;
8c681e07 NP	558	base += 256 * 4 + ((p->index_version < 2) ? 4 : 8);
	559	step = (p->index_version < 2) ? 24 : 20;
	560	while (off < p->num_objects * step) {
c283ab21	561	llist_insert_back(l.all_objects, base + off);
8c681e07	562	off += step;
c283ab21 LS	563	}
	564	/* this list will be pruned in cmp_two_packs later */
	565	l.unique_objects = llist_copy(l.all_objects);
1c3039e8 LS	566	if (p->pack_local)
	567	return pack_list_insert(&local_packs, &l);
	568	else
06a45c8c	569	return pack_list_insert(&altodb_packs, &l);
c283ab21 LS	570	}
c283ab21 LS	571
bd22c904	572	static struct pack_list * add_pack_file(char *filename)
c283ab21 LS	573	{
	574	struct packed_git *p = packed_git;
	575
	576	if (strlen(filename) < 40)
d7530708	577	die("Bad pack filename: %s", filename);
c283ab21 LS	578
	579	while (p) {
	580	if (strstr(p->pack_name, filename))
c283ab21 LS	581	return add_pack(p);
	582	p = p->next;
	583	}
d7530708	584	die("Filename %s not found in packed_git", filename);
c283ab21 LS	585	}
c283ab21 LS	586
bd22c904	587	static void load_all(void)
c283ab21 LS	588	{
	589	struct packed_git *p = packed_git;
	590
	591	while (p) {
1c3039e8	592	add_pack(p);
c283ab21 LS	593	p = p->next;
	594	}
	595	}
	596
	597	int main(int argc, char **argv)
	598	{
	599	int i;
	600	struct pack_list min, red, *pl;
bb931cf9	601	struct llist *ignore;
b99a394c JH	602	unsigned char *sha1;
b99a394c JH	603	char buf[42]; /* 40 byte sha1 + \n + \0 */
c283ab21	604
2fb3f6db SP	605	git_extract_argv0_path(argv[0]);
2fb3f6db SP	606
53228a5f JH	607	setup_git_directory();
53228a5f JH	608
c283ab21 LS	609	for (i = 1; i < argc; i++) {
c283ab21 LS	610	const char *arg = argv[i];
9bc0f32c LS	611	if(!strcmp(arg, "--")) {
9bc0f32c LS	612	i++;
c283ab21	613	break;
9bc0f32c	614	}
1c3039e8 LS	615	if(!strcmp(arg, "--all")) {
1c3039e8 LS	616	load_all_packs = 1;
c283ab21 LS	617	continue;
c283ab21 LS	618	}
1c3039e8	619	if(!strcmp(arg, "--verbose")) {
c283ab21 LS	620	verbose = 1;
	621	continue;
	622	}
1c3039e8 LS	623	if(!strcmp(arg, "--alt-odb")) {
	624	alt_odb = 1;
	625	continue;
	626	}
c283ab21	627	if(*arg == '-')
9bc0f32c	628	usage(pack_redundant_usage);
c283ab21 LS	629	else
	630	break;
	631	}
	632
	633	prepare_packed_git();
	634
1c3039e8	635	if (load_all_packs)
c283ab21 LS	636	load_all();
	637	else
	638	while (*(argv + i) != NULL)
	639	add_pack_file(*(argv + i++));
	640
1c3039e8	641	if (local_packs == NULL)
d7530708	642	die("Zero packs found!");
c283ab21	643
c283ab21 LS	644	load_all_objects();
c283ab21 LS	645
06a45c8c LS	646	cmp_local_packs();
	647	if (alt_odb)
	648	scan_alt_odb_packs();
	649
bb931cf9 LS	650	/* ignore objects given on stdin */
	651	llist_init(&ignore);
	652	if (!isatty(0)) {
	653	while (fgets(buf, sizeof(buf), stdin)) {
	654	sha1 = xmalloc(20);
	655	if (get_sha1_hex(buf, sha1))
	656	die("Bad sha1 on stdin: %s", buf);
	657	llist_insert_sorted_unique(ignore, sha1, NULL);
	658	}
	659	}
	660	llist_sorted_difference_inplace(all_objects, ignore);
	661	pl = local_packs;
	662	while (pl) {
	663	llist_sorted_difference_inplace(pl->unique_objects, ignore);
	664	pl = pl->next;
	665	}
	666
c283ab21	667	minimize(&min);
06a45c8c	668
c283ab21	669	if (verbose) {
abacbe41 KR	670	fprintf(stderr, "There are %lu packs available in alt-odbs.\n",
abacbe41 KR	671	(unsigned long)pack_list_size(altodb_packs));
c283ab21 LS	672	fprintf(stderr, "The smallest (bytewise) set of packs is:\n");
	673	pl = min;
	674	while (pl) {
	675	fprintf(stderr, "\t%s\n", pl->pack->pack_name);
	676	pl = pl->next;
	677	}
abacbe41 KR	678	fprintf(stderr, "containing %lu duplicate objects "
	679	"with a total size of %lukb.\n",
	680	(unsigned long)get_pack_redundancy(min),
	681	(unsigned long)pack_set_bytecount(min)/1024);
	682	fprintf(stderr, "A total of %lu unique objects were considered.\n",
	683	(unsigned long)all_objects->size);
c283ab21 LS	684	fprintf(stderr, "Redundant packs (with indexes):\n");
c283ab21 LS	685	}
1c3039e8	686	pl = red = pack_list_difference(local_packs, min);
c283ab21 LS	687	while (pl) {
c283ab21 LS	688	printf("%s\n%s\n",
1c3039e8 LS	689	sha1_pack_index_name(pl->pack->sha1),
1c3039e8 LS	690	pl->pack->pack_name);
c283ab21 LS	691	pl = pl->next;
c283ab21 LS	692	}
bb931cf9	693	if (verbose)
b99a394c JH	694	fprintf(stderr, "%luMB of redundant packs in total.\n",
b99a394c JH	695	(unsigned long)pack_set_bytecount(red)/(1024*1024));
c283ab21 LS	696
	697	return 0;
	698	}