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tag: v1.5.3.1
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/*
*
* Copyright 2005, Lukas Sandstrom <lukass@etek.chalmers.se>
*
* This file is licensed under the GPL v2.
*
*/
#include "cache.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!\n");
/* 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\n", filename);
while (p) {
if (strstr(p->pack_name, filename))
return add_pack(p);
p = p->next;
}
die("Filename %s not found in packed_git\n", 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 */
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!\n");
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;
}
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