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git/builtin/pack-redundant.c

672 lines
15 KiB

/*
*
* Copyright 2005, Lukas Sandstrom <lukass@etek.chalmers.se>
*
* This file is licensed under the GPL v2.
*
*/
#include "builtin.h"
#include "repository.h"
#include "packfile.h"
#include "object-store.h"
#define BLKSIZE 512
static const char pack_redundant_usage[] =
"git pack-redundant [--verbose] [--alt-odb] (--all | <filename.pack>...)";
static int load_all_packs, verbose, alt_odb;
struct llist_item {
struct llist_item *next;
struct object_id oid;
};
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 *remaining_objects;
size_t all_objects_size;
} *local_packs = NULL, *altodb_packs = NULL;
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_item;
if ( free_nodes ) {
new_item = free_nodes;
free_nodes = free_nodes->next;
} else {
int i = 1;
ALLOC_ARRAY(new_item, BLKSIZE);
for (; i < BLKSIZE; i++)
llist_item_put(&new_item[i]);
}
return new_item;
}
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_item, *old_item, *prev;
llist_init(&ret);
if ((ret->size = list->size) == 0)
return ret;
new_item = ret->front = llist_item_get();
new_item->oid = list->front->oid;
old_item = list->front->next;
while (old_item) {
prev = new_item;
new_item = llist_item_get();
prev->next = new_item;
new_item->oid = old_item->oid;
old_item = old_item->next;
}
new_item->next = NULL;
ret->back = new_item;
return ret;
}
static inline struct llist_item *llist_insert(struct llist *list,
struct llist_item *after,
const unsigned char *oid)
{
struct llist_item *new_item = llist_item_get();
oidread(&new_item->oid, oid);
new_item->next = NULL;
if (after) {
new_item->next = after->next;
after->next = new_item;
if (after == list->back)
list->back = new_item;
} else {/* insert in front */
if (list->size == 0)
list->back = new_item;
else
new_item->next = list->front;
list->front = new_item;
}
list->size++;
return new_item;
}
static inline struct llist_item *llist_insert_back(struct llist *list,
const unsigned char *oid)
{
return llist_insert(list, list->back, oid);
}
static inline struct llist_item *llist_insert_sorted_unique(struct llist *list,
const struct object_id *oid, struct llist_item *hint)
{
struct llist_item *prev = NULL, *l;
l = (hint == NULL) ? list->front : hint;
while (l) {
int cmp = oidcmp(&l->oid, oid);
if (cmp > 0) { /* we insert before this entry */
return llist_insert(list, prev, oid->hash);
}
if (!cmp) { /* already exists */
return l;
}
prev = l;
l = l->next;
}
/* insert at the end */
return llist_insert_back(list, oid->hash);
}
/* returns a pointer to an item in front of sha1 */
static inline struct llist_item * llist_sorted_remove(struct llist *list, const unsigned char *oid, struct llist_item *hint)
{
struct llist_item *prev, *l;
redo_from_start:
l = (hint == NULL) ? list->front : hint;
prev = NULL;
while (l) {
const int cmp = hashcmp(l->oid.hash, oid);
if (cmp > 0) /* not in list, since sorted */
return prev;
if (!cmp) { /* found */
if (!prev) {
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->oid.hash, 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)
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)
{
size_t 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;
const unsigned int hashsz = the_hash_algo->rawsz;
if (!p1->unique_objects)
p1->unique_objects = llist_copy(p1->remaining_objects);
if (!p2->unique_objects)
p2->unique_objects = llist_copy(p2->remaining_objects);
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 = hashsz + ((p1->pack->index_version < 2) ? 4 : 0);
p2_step = hashsz + ((p2->pack->index_version < 2) ? 4 : 0);
while (p1_off < p1->pack->num_objects * p1_step &&
p2_off < p2->pack->num_objects * p2_step)
{
const 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 size_t sizeof_union(struct packed_git *p1, struct packed_git *p2)
{
size_t ret = 0;
size_t p1_off = 0, p2_off = 0, p1_step, p2_step;
const unsigned char *p1_base, *p2_base;
const unsigned int hashsz = the_hash_algo->rawsz;
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 = hashsz + ((p1->index_version < 2) ? 4 : 0);
p2_step = hashsz + ((p2->index_version < 2) ? 4 : 0);
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)
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 int cmp_remaining_objects(const void *a, const void *b)
{
struct pack_list *pl_a = *((struct pack_list **)a);
struct pack_list *pl_b = *((struct pack_list **)b);
if (pl_a->remaining_objects->size == pl_b->remaining_objects->size) {
/* have the same remaining_objects, big pack first */
if (pl_a->all_objects_size == pl_b->all_objects_size)
return 0;
else if (pl_a->all_objects_size < pl_b->all_objects_size)
return 1;
else
return -1;
} else if (pl_a->remaining_objects->size < pl_b->remaining_objects->size) {
/* sort by remaining objects, more objects first */
return 1;
} else {
return -1;
}
}
/* Sort pack_list, greater size of remaining_objects first */
static void sort_pack_list(struct pack_list **pl)
{
struct pack_list **ary, *p;
int i;
size_t n = pack_list_size(*pl);
if (n < 2)
return;
/* prepare an array of packed_list for easier sorting */
CALLOC_ARRAY(ary, n);
for (n = 0, p = *pl; p; p = p->next)
ary[n++] = p;
QSORT(ary, n, cmp_remaining_objects);
/* link them back again */
for (i = 0; i < n - 1; i++)
ary[i]->next = ary[i + 1];
ary[n - 1]->next = NULL;
*pl = ary[0];
free(ary);
}
static void minimize(struct pack_list **min)
{
struct pack_list *pl, *unique = NULL, *non_unique = NULL;
struct llist *missing, *unique_pack_objects;
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->remaining_objects);
pl = pl->next;
}
*min = unique;
/* return if there are no objects missing from the unique set */
if (missing->size == 0) {
free(missing);
return;
}
unique_pack_objects = llist_copy(all_objects);
llist_sorted_difference_inplace(unique_pack_objects, missing);
/* remove unique pack objects from the non_unique packs */
pl = non_unique;
while (pl) {
llist_sorted_difference_inplace(pl->remaining_objects, unique_pack_objects);
pl = pl->next;
}
while (non_unique) {
/* sort the non_unique packs, greater size of remaining_objects first */
sort_pack_list(&non_unique);
if (non_unique->remaining_objects->size == 0)
break;
pack_list_insert(min, non_unique);
for (pl = non_unique->next; pl && pl->remaining_objects->size > 0; pl = pl->next)
llist_sorted_difference_inplace(pl->remaining_objects, non_unique->remaining_objects);
non_unique = non_unique->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->remaining_objects->front;
while (l) {
hint = llist_insert_sorted_unique(all_objects,
&l->oid, 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->remaining_objects);
pl = pl->next;
}
}
/* this scales like O(n^2) */
static void cmp_local_packs(void)
{
struct pack_list *subset, *pl = local_packs;
/* only one packfile */
if (!pl->next) {
llist_init(&pl->unique_objects);
return;
}
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->remaining_objects,
alt->remaining_objects);
local = local->next;
}
alt = alt->next;
}
}
static struct pack_list * add_pack(struct packed_git *p)
{
struct pack_list l;
size_t off = 0, step;
const unsigned char *base;
if (!p->pack_local && !(alt_odb || verbose))
return NULL;
l.pack = p;
llist_init(&l.remaining_objects);
if (open_pack_index(p))
return NULL;
base = p->index_data;
base += 256 * 4 + ((p->index_version < 2) ? 4 : 8);
step = the_hash_algo->rawsz + ((p->index_version < 2) ? 4 : 0);
while (off < p->num_objects * step) {
llist_insert_back(l.remaining_objects, base + off);
off += step;
}
l.all_objects_size = l.remaining_objects->size;
l.unique_objects = NULL;
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 = get_all_packs(the_repository);
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 = get_all_packs(the_repository);
while (p) {
add_pack(p);
p = p->next;
}
}
int cmd_pack_redundant(int argc, const char **argv, const char *prefix)
{
int i;
int i_still_use_this = 0;
struct pack_list *min = NULL, *red, *pl;
struct llist *ignore;
struct object_id *oid;
char buf[GIT_MAX_HEXSZ + 2]; /* hex hash + \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 (!strcmp(arg, "--i-still-use-this")) {
i_still_use_this = 1;
continue;
}
if (*arg == '-')
usage(pack_redundant_usage);
else
break;
}
if (!i_still_use_this) {
fputs(_("'git pack-redundant' is nominated for removal.\n"
"If you still use this command, please add an extra\n"
"option, '--i-still-use-this', on the command line\n"
"and let us know you still use it by sending an e-mail\n"
"to <git@vger.kernel.org>. Thanks.\n"), stderr);
}
if (load_all_packs)
load_all();
else
while (*(argv + i) != NULL)
add_pack_file(*(argv + i++));
if (!local_packs)
die("Zero packs found!");
load_all_objects();
if (alt_odb)
scan_alt_odb_packs();
/* ignore objects given on stdin */
llist_init(&ignore);
if (!isatty(0)) {
while (fgets(buf, sizeof(buf), stdin)) {
oid = xmalloc(sizeof(*oid));
if (get_oid_hex(buf, oid))
die("Bad object ID on stdin: %s", buf);
llist_insert_sorted_unique(ignore, oid, NULL);
}
}
llist_sorted_difference_inplace(all_objects, ignore);
pl = local_packs;
while (pl) {
llist_sorted_difference_inplace(pl->remaining_objects, ignore);
pl = pl->next;
}
cmp_local_packs();
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->hash),
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;
}