mirror of
https://github.com/git/git.git
synced 2024-11-30 21:44:02 +08:00
4287307833
Especially with the new index format to come, it is more appropriate to encapsulate more into check_packed_git_idx() and assume less of the index format in struct packed_git. To that effect, the index_base is renamed to index_data with void * type so it is not used directly but other pointers initialized with it. This allows for a couple pointer cast removal, as well as providing a better generic name to grep for when adding support for new index versions or formats. And index_data is declared const too while at it. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
686 lines
14 KiB
C
686 lines
14 KiB
C
/*
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*
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* Copyright 2005, Lukas Sandstrom <lukass@etek.chalmers.se>
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*
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* This file is licensed under the GPL v2.
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*
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*/
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#include "cache.h"
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#define BLKSIZE 512
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static const char pack_redundant_usage[] =
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"git-pack-redundant [ --verbose ] [ --alt-odb ] < --all | <.pack filename> ...>";
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static int load_all_packs, verbose, alt_odb;
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struct llist_item {
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struct llist_item *next;
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const unsigned char *sha1;
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};
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static struct llist {
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struct llist_item *front;
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struct llist_item *back;
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size_t size;
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} *all_objects; /* all objects which must be present in local packfiles */
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static struct pack_list {
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struct pack_list *next;
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struct packed_git *pack;
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struct llist *unique_objects;
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struct llist *all_objects;
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} *local_packs = NULL, *altodb_packs = NULL;
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struct pll {
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struct pll *next;
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struct pack_list *pl;
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};
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static struct llist_item *free_nodes;
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static inline void llist_item_put(struct llist_item *item)
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{
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item->next = free_nodes;
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free_nodes = item;
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}
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static inline struct llist_item *llist_item_get(void)
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{
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struct llist_item *new;
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if ( free_nodes ) {
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new = free_nodes;
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free_nodes = free_nodes->next;
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} else {
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int i = 1;
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new = xmalloc(sizeof(struct llist_item) * BLKSIZE);
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for(;i < BLKSIZE; i++) {
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llist_item_put(&new[i]);
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}
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}
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return new;
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}
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static void llist_free(struct llist *list)
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{
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while((list->back = list->front)) {
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list->front = list->front->next;
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llist_item_put(list->back);
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}
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free(list);
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}
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static inline void llist_init(struct llist **list)
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{
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*list = xmalloc(sizeof(struct llist));
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(*list)->front = (*list)->back = NULL;
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(*list)->size = 0;
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}
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static struct llist * llist_copy(struct llist *list)
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{
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struct llist *ret;
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struct llist_item *new, *old, *prev;
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llist_init(&ret);
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if ((ret->size = list->size) == 0)
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return ret;
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new = ret->front = llist_item_get();
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new->sha1 = list->front->sha1;
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old = list->front->next;
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while (old) {
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prev = new;
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new = llist_item_get();
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prev->next = new;
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new->sha1 = old->sha1;
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old = old->next;
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}
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new->next = NULL;
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ret->back = new;
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return ret;
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}
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static inline struct llist_item *llist_insert(struct llist *list,
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struct llist_item *after,
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const unsigned char *sha1)
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{
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struct llist_item *new = llist_item_get();
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new->sha1 = sha1;
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new->next = NULL;
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if (after != NULL) {
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new->next = after->next;
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after->next = new;
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if (after == list->back)
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list->back = new;
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} else {/* insert in front */
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if (list->size == 0)
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list->back = new;
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else
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new->next = list->front;
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list->front = new;
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}
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list->size++;
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return new;
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}
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static inline struct llist_item *llist_insert_back(struct llist *list,
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const unsigned char *sha1)
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{
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return llist_insert(list, list->back, sha1);
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}
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static inline struct llist_item *llist_insert_sorted_unique(struct llist *list,
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const unsigned char *sha1, struct llist_item *hint)
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{
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struct llist_item *prev = NULL, *l;
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l = (hint == NULL) ? list->front : hint;
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while (l) {
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int cmp = hashcmp(l->sha1, sha1);
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if (cmp > 0) { /* we insert before this entry */
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return llist_insert(list, prev, sha1);
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}
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if(!cmp) { /* already exists */
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return l;
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}
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prev = l;
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l = l->next;
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}
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/* insert at the end */
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return llist_insert_back(list, sha1);
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}
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/* returns a pointer to an item in front of sha1 */
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static inline struct llist_item * llist_sorted_remove(struct llist *list, const unsigned char *sha1, struct llist_item *hint)
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{
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struct llist_item *prev, *l;
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redo_from_start:
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l = (hint == NULL) ? list->front : hint;
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prev = NULL;
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while (l) {
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int cmp = hashcmp(l->sha1, sha1);
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if (cmp > 0) /* not in list, since sorted */
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return prev;
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if(!cmp) { /* found */
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if (prev == NULL) {
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if (hint != NULL && hint != list->front) {
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/* we don't know the previous element */
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hint = NULL;
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goto redo_from_start;
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}
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list->front = l->next;
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} else
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prev->next = l->next;
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if (l == list->back)
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list->back = prev;
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llist_item_put(l);
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list->size--;
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return prev;
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}
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prev = l;
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l = l->next;
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}
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return prev;
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}
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/* computes A\B */
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static void llist_sorted_difference_inplace(struct llist *A,
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struct llist *B)
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{
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struct llist_item *hint, *b;
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hint = NULL;
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b = B->front;
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while (b) {
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hint = llist_sorted_remove(A, b->sha1, hint);
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b = b->next;
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}
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}
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static inline struct pack_list * pack_list_insert(struct pack_list **pl,
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struct pack_list *entry)
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{
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struct pack_list *p = xmalloc(sizeof(struct pack_list));
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memcpy(p, entry, sizeof(struct pack_list));
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p->next = *pl;
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*pl = p;
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return p;
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}
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static inline size_t pack_list_size(struct pack_list *pl)
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{
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size_t ret = 0;
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while(pl) {
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ret++;
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pl = pl->next;
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}
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return ret;
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}
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static struct pack_list * pack_list_difference(const struct pack_list *A,
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const struct pack_list *B)
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{
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struct pack_list *ret;
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const struct pack_list *pl;
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if (A == NULL)
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return NULL;
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pl = B;
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while (pl != NULL) {
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if (A->pack == pl->pack)
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return pack_list_difference(A->next, B);
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pl = pl->next;
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}
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ret = xmalloc(sizeof(struct pack_list));
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memcpy(ret, A, sizeof(struct pack_list));
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ret->next = pack_list_difference(A->next, B);
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return ret;
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}
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static void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
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{
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int p1_off, p2_off;
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const unsigned char *p1_base, *p2_base;
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struct llist_item *p1_hint = NULL, *p2_hint = NULL;
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p1_off = p2_off = 256 * 4 + 4;
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p1_base = p1->pack->index_data;
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p2_base = p2->pack->index_data;
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while (p1_off <= p1->pack->index_size - 3 * 20 &&
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p2_off <= p2->pack->index_size - 3 * 20)
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{
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int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
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/* cmp ~ p1 - p2 */
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if (cmp == 0) {
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p1_hint = llist_sorted_remove(p1->unique_objects,
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p1_base + p1_off, p1_hint);
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p2_hint = llist_sorted_remove(p2->unique_objects,
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p1_base + p1_off, p2_hint);
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p1_off+=24;
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p2_off+=24;
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continue;
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}
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if (cmp < 0) { /* p1 has the object, p2 doesn't */
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p1_off+=24;
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} else { /* p2 has the object, p1 doesn't */
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p2_off+=24;
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}
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}
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}
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static void pll_free(struct pll *l)
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{
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struct pll *old;
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struct pack_list *opl;
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while (l) {
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old = l;
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while (l->pl) {
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opl = l->pl;
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l->pl = opl->next;
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free(opl);
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}
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l = l->next;
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free(old);
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}
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}
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/* all the permutations have to be free()d at the same time,
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* since they refer to each other
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*/
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static struct pll * get_permutations(struct pack_list *list, int n)
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{
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struct pll *subset, *ret = NULL, *new_pll = NULL, *pll;
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if (list == NULL || pack_list_size(list) < n || n == 0)
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return NULL;
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if (n == 1) {
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while (list) {
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new_pll = xmalloc(sizeof(pll));
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new_pll->pl = NULL;
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pack_list_insert(&new_pll->pl, list);
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new_pll->next = ret;
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ret = new_pll;
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list = list->next;
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}
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return ret;
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}
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while (list->next) {
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subset = get_permutations(list->next, n - 1);
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while (subset) {
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new_pll = xmalloc(sizeof(pll));
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new_pll->pl = subset->pl;
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pack_list_insert(&new_pll->pl, list);
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new_pll->next = ret;
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ret = new_pll;
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subset = subset->next;
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}
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list = list->next;
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}
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return ret;
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}
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static int is_superset(struct pack_list *pl, struct llist *list)
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{
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struct llist *diff;
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diff = llist_copy(list);
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while (pl) {
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llist_sorted_difference_inplace(diff, pl->all_objects);
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if (diff->size == 0) { /* we're done */
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llist_free(diff);
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return 1;
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}
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pl = pl->next;
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}
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llist_free(diff);
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return 0;
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}
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static size_t sizeof_union(struct packed_git *p1, struct packed_git *p2)
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{
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size_t ret = 0;
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int p1_off, p2_off;
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const unsigned char *p1_base, *p2_base;
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p1_off = p2_off = 256 * 4 + 4;
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p1_base = p1->index_data;
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p2_base = p2->index_data;
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while (p1_off <= p1->index_size - 3 * 20 &&
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p2_off <= p2->index_size - 3 * 20)
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{
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int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
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/* cmp ~ p1 - p2 */
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if (cmp == 0) {
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ret++;
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p1_off+=24;
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p2_off+=24;
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continue;
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}
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if (cmp < 0) { /* p1 has the object, p2 doesn't */
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p1_off+=24;
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} else { /* p2 has the object, p1 doesn't */
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p2_off+=24;
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}
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}
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return ret;
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}
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/* another O(n^2) function ... */
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static size_t get_pack_redundancy(struct pack_list *pl)
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{
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struct pack_list *subset;
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size_t ret = 0;
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if (pl == NULL)
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return 0;
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while ((subset = pl->next)) {
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while(subset) {
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ret += sizeof_union(pl->pack, subset->pack);
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subset = subset->next;
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}
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pl = pl->next;
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}
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return ret;
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}
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static inline off_t pack_set_bytecount(struct pack_list *pl)
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{
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off_t ret = 0;
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while (pl) {
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ret += pl->pack->pack_size;
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ret += pl->pack->index_size;
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pl = pl->next;
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}
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return ret;
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}
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static void minimize(struct pack_list **min)
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{
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struct pack_list *pl, *unique = NULL,
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*non_unique = NULL, *min_perm = NULL;
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struct pll *perm, *perm_all, *perm_ok = NULL, *new_perm;
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struct llist *missing;
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off_t min_perm_size = 0, perm_size;
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int n;
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pl = local_packs;
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while (pl) {
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if(pl->unique_objects->size)
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pack_list_insert(&unique, pl);
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else
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pack_list_insert(&non_unique, pl);
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pl = pl->next;
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}
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/* find out which objects are missing from the set of unique packs */
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missing = llist_copy(all_objects);
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pl = unique;
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while (pl) {
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llist_sorted_difference_inplace(missing, pl->all_objects);
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pl = pl->next;
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}
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/* return if there are no objects missing from the unique set */
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if (missing->size == 0) {
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*min = unique;
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return;
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}
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/* find the permutations which contain all missing objects */
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for (n = 1; n <= pack_list_size(non_unique) && !perm_ok; n++) {
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perm_all = perm = get_permutations(non_unique, n);
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while (perm) {
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if (is_superset(perm->pl, missing)) {
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new_perm = xmalloc(sizeof(struct pll));
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memcpy(new_perm, perm, sizeof(struct pll));
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new_perm->next = perm_ok;
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perm_ok = new_perm;
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}
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perm = perm->next;
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}
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if (perm_ok)
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break;
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pll_free(perm_all);
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}
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if (perm_ok == NULL)
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die("Internal error: No complete sets found!\n");
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/* find the permutation with the smallest size */
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perm = perm_ok;
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while (perm) {
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perm_size = pack_set_bytecount(perm->pl);
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if (!min_perm_size || min_perm_size > perm_size) {
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min_perm_size = perm_size;
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min_perm = perm->pl;
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}
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perm = perm->next;
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}
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*min = min_perm;
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/* add the unique packs to the list */
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pl = unique;
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while(pl) {
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pack_list_insert(min, pl);
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pl = pl->next;
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}
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}
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static void load_all_objects(void)
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{
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struct pack_list *pl = local_packs;
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struct llist_item *hint, *l;
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llist_init(&all_objects);
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while (pl) {
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hint = NULL;
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l = pl->all_objects->front;
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while (l) {
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hint = llist_insert_sorted_unique(all_objects,
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l->sha1, hint);
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l = l->next;
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}
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pl = pl->next;
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}
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/* remove objects present in remote packs */
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pl = altodb_packs;
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while (pl) {
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llist_sorted_difference_inplace(all_objects, pl->all_objects);
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pl = pl->next;
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}
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}
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/* this scales like O(n^2) */
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static void cmp_local_packs(void)
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{
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struct pack_list *subset, *pl = local_packs;
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while ((subset = pl)) {
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while((subset = subset->next))
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cmp_two_packs(pl, subset);
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pl = pl->next;
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}
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}
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static void scan_alt_odb_packs(void)
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{
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struct pack_list *local, *alt;
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alt = altodb_packs;
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while (alt) {
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local = local_packs;
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while (local) {
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llist_sorted_difference_inplace(local->unique_objects,
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alt->all_objects);
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local = local->next;
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}
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llist_sorted_difference_inplace(all_objects, alt->all_objects);
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alt = alt->next;
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}
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}
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static struct pack_list * add_pack(struct packed_git *p)
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{
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struct pack_list l;
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size_t off;
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const unsigned char *base;
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if (!p->pack_local && !(alt_odb || verbose))
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return NULL;
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l.pack = p;
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llist_init(&l.all_objects);
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off = 256 * 4 + 4;
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base = p->index_data;
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while (off <= p->index_size - 3 * 20) {
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llist_insert_back(l.all_objects, base + off);
|
|
off += 24;
|
|
}
|
|
/* 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;
|
|
}
|