make "git pack-redundant" a built-in

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Makefile b/Makefile
index 88e2f8fd494d1feea1e36ec85f7de2968e57e294..33f987088645f974e6ac50fa48fe4cc5b7b26514 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -389,7 +389,6 @@ PROGRAMS += $(EXTRA_PROGRAMS)
 PROGRAMS += git-fast-import$X
 PROGRAMS += git-imap-send$X
 PROGRAMS += git-index-pack$X
-PROGRAMS += git-pack-redundant$X
 PROGRAMS += git-shell$X
 PROGRAMS += git-show-index$X
 PROGRAMS += git-upload-pack$X
@@ -673,6 +672,7 @@ BUILTIN_OBJS += builtin-mktree.o
 BUILTIN_OBJS += builtin-mv.o
 BUILTIN_OBJS += builtin-name-rev.o
 BUILTIN_OBJS += builtin-pack-objects.o
+BUILTIN_OBJS += builtin-pack-redundant.o
 BUILTIN_OBJS += builtin-pack-refs.o
 BUILTIN_OBJS += builtin-patch-id.o
 BUILTIN_OBJS += builtin-prune-packed.o

diff --git a/builtin-pack-redundant.c b/builtin-pack-redundant.c
new file mode 100644 (file)
index 0000000..41e1615
--- /dev/null
+++ b/builtin-pack-redundant.c
@@ -0,0 +1,696 @@
+/*
+*
+* 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(const 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 cmd_pack_redundant(int argc, const char **argv, const char *prefix)
+{
+       int i;
+       struct pack_list *min, *red, *pl;
+       struct llist *ignore;
+       unsigned char *sha1;
+       char buf[42]; /* 40 byte sha1 + \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 (*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;
+}

diff --git a/builtin.h b/builtin.h
index d4fec89a15d9373746ce6a833ed27cfdb7d32656..bd7f737485d24fe0203b9d39291426847efc1bf7 100644 (file)
--- a/builtin.h
+++ b/builtin.h
@@ -78,6 +78,7 @@ extern int cmd_mktree(int argc, const char **argv, const char *prefix);
 extern int cmd_mv(int argc, const char **argv, const char *prefix);
 extern int cmd_name_rev(int argc, const char **argv, const char *prefix);
 extern int cmd_pack_objects(int argc, const char **argv, const char *prefix);
+extern int cmd_pack_redundant(int argc, const char **argv, const char *prefix);
 extern int cmd_patch_id(int argc, const char **argv, const char *prefix);
 extern int cmd_pickaxe(int argc, const char **argv, const char *prefix);
 extern int cmd_prune(int argc, const char **argv, const char *prefix);

diff --git a/git.c b/git.c
index 832bd2d535eab1a73700a2c17114ee5c34fd1aeb..6cc1eba29e71fb4bbb26789ff71b21041442720b 100644 (file)
--- a/git.c
+++ b/git.c
@@ -343,6 +343,7 @@ static void handle_internal_command(int argc, const char **argv)
                { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
                { "name-rev", cmd_name_rev, RUN_SETUP },
                { "pack-objects", cmd_pack_objects, RUN_SETUP },
+               { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
                { "patch-id", cmd_patch_id },
                { "peek-remote", cmd_ls_remote },
                { "pickaxe", cmd_blame, RUN_SETUP },

diff --git a/pack-redundant.c b/pack-redundant.c
deleted file mode 100644 (file)
index 21c61db..0000000
--- a/pack-redundant.c
+++ /dev/null
@@ -1,700 +0,0 @@
-/*
-*
-* 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]);
-
-       if (argc == 2 && !strcmp(argv[1], "-h"))
-               usage(pack_redundant_usage);
-
-       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;
-}