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-rw-r--r--pack-redundant.c620
1 files changed, 620 insertions, 0 deletions
diff --git a/pack-redundant.c b/pack-redundant.c
new file mode 100644
index 0000000..1f8c577
--- /dev/null
+++ b/pack-redundant.c
@@ -0,0 +1,620 @@
+/*
+*
+* Copyright 2005, Lukas Sandstrom <lukass@etek.chalmers.se>
+*
+* This file is licensed under the GPL v2.
+*
+*/
+
+#include "cache.h"
+
+static const char pack_redundant_usage[] =
+"git-pack-redundant [ --verbose ] [ --alt-odb ] < --all | <.pack filename> ...>";
+
+int load_all_packs = 0, verbose = 0, alt_odb = 0;
+
+struct llist_item {
+ struct llist_item *next;
+ char *sha1;
+};
+struct llist {
+ struct llist_item *front;
+ struct llist_item *back;
+ size_t size;
+} *all_objects; /* all objects which must be present in local packfiles */
+
+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;
+};
+
+inline void llist_free(struct llist *list)
+{
+ while((list->back = list->front)) {
+ list->front = list->front->next;
+ free(list->back);
+ }
+ free(list);
+}
+
+inline void llist_init(struct llist **list)
+{
+ *list = xmalloc(sizeof(struct llist));
+ (*list)->front = (*list)->back = NULL;
+ (*list)->size = 0;
+}
+
+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 = xmalloc(sizeof(struct llist_item));
+ new->sha1 = list->front->sha1;
+
+ old = list->front->next;
+ while (old) {
+ prev = new;
+ new = xmalloc(sizeof(struct llist_item));
+ prev->next = new;
+ new->sha1 = old->sha1;
+ old = old->next;
+ }
+ new->next = NULL;
+ ret->back = new;
+
+ return ret;
+}
+
+inline struct llist_item * llist_insert(struct llist *list,
+ struct llist_item *after, char *sha1)
+{
+ struct llist_item *new = xmalloc(sizeof(struct llist_item));
+ 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;
+}
+
+inline struct llist_item * llist_insert_back(struct llist *list, char *sha1)
+{
+ return llist_insert(list, list->back, sha1);
+}
+
+inline struct llist_item * llist_insert_sorted_unique(struct llist *list,
+ char *sha1, struct llist_item *hint)
+{
+ struct llist_item *prev = NULL, *l;
+
+ l = (hint == NULL) ? list->front : hint;
+ while (l) {
+ int cmp = memcmp(l->sha1, sha1, 20);
+ 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);
+}
+
+/* computes A\B */
+void llist_sorted_difference_inplace(struct llist *A,
+ struct llist *B)
+{
+ struct llist_item *prev, *a, *b, *x;
+
+ prev = a = A->front;
+ b = B->front;
+
+ while (a != NULL && b != NULL) {
+ int cmp = memcmp(a->sha1, b->sha1, 20);
+ if (!cmp) {
+ x = a;
+ if (a == A->front)
+ A->front = a->next;
+ a = prev->next = a->next;
+
+ if (a == NULL) /* end of list */
+ A->back = prev;
+ A->size--;
+ free(x);
+ b = b->next;
+ } else
+ if (cmp > 0)
+ b = b->next;
+ else {
+ prev = a;
+ a = a->next;
+ }
+ }
+}
+
+/* returns a pointer to an item in front of sha1 */
+inline struct llist_item * llist_sorted_remove(struct llist *list, 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 = memcmp(l->sha1, sha1, 20);
+ 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;
+ free(l);
+ list->size--;
+ return prev;
+ }
+ prev = l;
+ l = l->next;
+ }
+ return prev;
+}
+
+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;
+}
+
+inline size_t pack_list_size(struct pack_list *pl)
+{
+ size_t ret = 0;
+ while(pl) {
+ ret++;
+ pl = pl->next;
+ }
+ return ret;
+}
+
+struct pack_list * pack_list_difference(struct pack_list *A,
+ struct pack_list *B)
+{
+ struct pack_list *ret, *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;
+}
+
+void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
+{
+ int p1_off, p2_off;
+ void *p1_base, *p2_base;
+ struct llist_item *p1_hint = NULL, *p2_hint = NULL;
+
+ p1_off = p2_off = 256 * 4 + 4;
+ p1_base = (void *)p1->pack->index_base;
+ p2_base = (void *)p2->pack->index_base;
+
+ while (p1_off <= p1->pack->index_size - 3 * 20 &&
+ p2_off <= p2->pack->index_size - 3 * 20)
+ {
+ int cmp = memcmp(p1_base + p1_off, p2_base + p2_off, 20);
+ /* 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+=24;
+ p2_off+=24;
+ continue;
+ }
+ if (cmp < 0) { /* p1 has the object, p2 doesn't */
+ p1_off+=24;
+ } else { /* p2 has the object, p1 doesn't */
+ p2_off+=24;
+ }
+ }
+}
+
+/* all the permutations have to be free()d at the same time,
+ * since they refer to each other
+ */
+struct pll * get_all_permutations(struct pack_list *list)
+{
+ struct pll *subset, *pll, *new_pll = NULL; /*silence warning*/
+
+ if (list == NULL)
+ return NULL;
+
+ if (list->next == NULL) {
+ new_pll = xmalloc(sizeof(struct pll));
+ new_pll->next = NULL;
+ new_pll->pl = list;
+ return new_pll;
+ }
+
+ pll = subset = get_all_permutations(list->next);
+ while (pll) {
+ new_pll = xmalloc(sizeof(struct pll));
+ new_pll->next = pll->next;
+ pll->next = new_pll;
+
+ new_pll->pl = xmalloc(sizeof(struct pack_list));
+ memcpy(new_pll->pl, list, sizeof(struct pack_list));
+ new_pll->pl->next = pll->pl;
+
+ pll = new_pll->next;
+ }
+ /* add ourself to the end */
+ new_pll->next = xmalloc(sizeof(struct pll));
+ new_pll->next->pl = xmalloc(sizeof(struct pack_list));
+ new_pll->next->next = NULL;
+ memcpy(new_pll->next->pl, list, sizeof(struct pack_list));
+ new_pll->next->pl->next = NULL;
+
+ return subset;
+}
+
+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;
+}
+
+size_t sizeof_union(struct packed_git *p1, struct packed_git *p2)
+{
+ size_t ret = 0;
+ int p1_off, p2_off;
+ void *p1_base, *p2_base;
+
+ p1_off = p2_off = 256 * 4 + 4;
+ p1_base = (void *)p1->index_base;
+ p2_base = (void *)p2->index_base;
+
+ while (p1_off <= p1->index_size - 3 * 20 &&
+ p2_off <= p2->index_size - 3 * 20)
+ {
+ int cmp = memcmp(p1_base + p1_off, p2_base + p2_off, 20);
+ /* cmp ~ p1 - p2 */
+ if (cmp == 0) {
+ ret++;
+ p1_off+=24;
+ p2_off+=24;
+ continue;
+ }
+ if (cmp < 0) { /* p1 has the object, p2 doesn't */
+ p1_off+=24;
+ } else { /* p2 has the object, p1 doesn't */
+ p2_off+=24;
+ }
+ }
+ return ret;
+}
+
+/* another O(n^2) function ... */
+size_t get_pack_redundancy(struct pack_list *pl)
+{
+ struct pack_list *subset;
+
+ if (pl == NULL)
+ return 0;
+
+ size_t ret = 0;
+ while ((subset = pl->next)) {
+ while(subset) {
+ ret += sizeof_union(pl->pack, subset->pack);
+ subset = subset->next;
+ }
+ pl = pl->next;
+ }
+ return ret;
+}
+
+inline size_t pack_set_bytecount(struct pack_list *pl)
+{
+ size_t ret = 0;
+ while (pl) {
+ ret += pl->pack->pack_size;
+ ret += pl->pack->index_size;
+ pl = pl->next;
+ }
+ return ret;
+}
+
+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;
+ size_t min_perm_size = (size_t)-1, perm_size;
+
+ 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 */
+ perm_all = perm = get_all_permutations(non_unique);
+ while (perm) {
+ if (is_superset(perm->pl, missing)) {
+ new_perm = xmalloc(sizeof(struct pll));
+ new_perm->pl = perm->pl;
+ new_perm->next = perm_ok;
+ perm_ok = new_perm;
+ }
+ perm = perm->next;
+ }
+
+ 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 > 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;
+ }
+}
+
+void load_all_objects()
+{
+ struct pack_list *pl = local_packs;
+ struct llist_item *hint, *l;
+ int i;
+
+ llist_init(&all_objects);
+
+ while (pl) {
+ i = 0;
+ 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) */
+void cmp_packs()
+{
+ struct pack_list *subset, *pl = local_packs;
+
+ while ((subset = pl)) {
+ while((subset = subset->next))
+ cmp_two_packs(pl, subset);
+ pl = pl->next;
+ }
+
+ pl = altodb_packs;
+ while (pl) {
+ subset = local_packs;
+ while (subset) {
+ llist_sorted_difference_inplace(subset->unique_objects,
+ pl->all_objects);
+ subset = subset->next;
+ }
+ pl = pl->next;
+ }
+}
+
+struct pack_list * add_pack(struct packed_git *p)
+{
+ struct pack_list l;
+ size_t off;
+ void *base;
+
+ l.pack = p;
+ llist_init(&l.all_objects);
+
+ off = 256 * 4 + 4;
+ base = (void *)p->index_base;
+ while (off <= p->index_size - 3 * 20) {
+ 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 alt_odb ? pack_list_insert(&altodb_packs, &l) : NULL;
+}
+
+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);
+}
+
+void load_all()
+{
+ 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;
+
+ 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");
+
+ cmp_packs();
+
+ load_all_objects();
+
+ minimize(&min);
+ if (verbose) {
+ fprintf(stderr, "There are %ld packs available in alt-odbs.\n",
+ 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 %ld duplicate objects "
+ "with a total size of %ldkb.\n",
+ get_pack_redundancy(min), pack_set_bytecount(min)/1024);
+ fprintf(stderr, "A total of %ld unique objects were considered.\n",
+ 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;
+ }
+
+ return 0;
+}
generated by cgit v0.10.2-6-g49f6 at 2024-04-19 12:38:53 (GMT)