gitweb: use new Git::Repo API, and add optional caching
[git/gitweb-caching.git] / pack-redundant.c
blob25b81a445c8fafe0c00ce30082b7d9a7c22ccf1e
1 /*
3 * Copyright 2005, Lukas Sandstrom <lukass@etek.chalmers.se>
5 * This file is licensed under the GPL v2.
7 */
9 #include "cache.h"
11 #define BLKSIZE 512
13 static const char pack_redundant_usage[] =
14 "git pack-redundant [ --verbose ] [ --alt-odb ] < --all | <.pack filename> ...>";
16 static int load_all_packs, verbose, alt_odb;
18 struct llist_item {
19 struct llist_item *next;
20 const unsigned char *sha1;
22 static struct llist {
23 struct llist_item *front;
24 struct llist_item *back;
25 size_t size;
26 } *all_objects; /* all objects which must be present in local packfiles */
28 static struct pack_list {
29 struct pack_list *next;
30 struct packed_git *pack;
31 struct llist *unique_objects;
32 struct llist *all_objects;
33 } *local_packs = NULL, *altodb_packs = NULL;
35 struct pll {
36 struct pll *next;
37 struct pack_list *pl;
40 static struct llist_item *free_nodes;
42 static inline void llist_item_put(struct llist_item *item)
44 item->next = free_nodes;
45 free_nodes = item;
48 static inline struct llist_item *llist_item_get(void)
50 struct llist_item *new;
51 if ( free_nodes ) {
52 new = free_nodes;
53 free_nodes = free_nodes->next;
54 } else {
55 int i = 1;
56 new = xmalloc(sizeof(struct llist_item) * BLKSIZE);
57 for(;i < BLKSIZE; i++) {
58 llist_item_put(&new[i]);
61 return new;
64 static void llist_free(struct llist *list)
66 while((list->back = list->front)) {
67 list->front = list->front->next;
68 llist_item_put(list->back);
70 free(list);
73 static inline void llist_init(struct llist **list)
75 *list = xmalloc(sizeof(struct llist));
76 (*list)->front = (*list)->back = NULL;
77 (*list)->size = 0;
80 static struct llist * llist_copy(struct llist *list)
82 struct llist *ret;
83 struct llist_item *new, *old, *prev;
85 llist_init(&ret);
87 if ((ret->size = list->size) == 0)
88 return ret;
90 new = ret->front = llist_item_get();
91 new->sha1 = list->front->sha1;
93 old = list->front->next;
94 while (old) {
95 prev = new;
96 new = llist_item_get();
97 prev->next = new;
98 new->sha1 = old->sha1;
99 old = old->next;
101 new->next = NULL;
102 ret->back = new;
104 return ret;
107 static inline struct llist_item *llist_insert(struct llist *list,
108 struct llist_item *after,
109 const unsigned char *sha1)
111 struct llist_item *new = llist_item_get();
112 new->sha1 = sha1;
113 new->next = NULL;
115 if (after != NULL) {
116 new->next = after->next;
117 after->next = new;
118 if (after == list->back)
119 list->back = new;
120 } else {/* insert in front */
121 if (list->size == 0)
122 list->back = new;
123 else
124 new->next = list->front;
125 list->front = new;
127 list->size++;
128 return new;
131 static inline struct llist_item *llist_insert_back(struct llist *list,
132 const unsigned char *sha1)
134 return llist_insert(list, list->back, sha1);
137 static inline struct llist_item *llist_insert_sorted_unique(struct llist *list,
138 const unsigned char *sha1, struct llist_item *hint)
140 struct llist_item *prev = NULL, *l;
142 l = (hint == NULL) ? list->front : hint;
143 while (l) {
144 int cmp = hashcmp(l->sha1, sha1);
145 if (cmp > 0) { /* we insert before this entry */
146 return llist_insert(list, prev, sha1);
148 if(!cmp) { /* already exists */
149 return l;
151 prev = l;
152 l = l->next;
154 /* insert at the end */
155 return llist_insert_back(list, sha1);
158 /* returns a pointer to an item in front of sha1 */
159 static inline struct llist_item * llist_sorted_remove(struct llist *list, const unsigned char *sha1, struct llist_item *hint)
161 struct llist_item *prev, *l;
163 redo_from_start:
164 l = (hint == NULL) ? list->front : hint;
165 prev = NULL;
166 while (l) {
167 int cmp = hashcmp(l->sha1, sha1);
168 if (cmp > 0) /* not in list, since sorted */
169 return prev;
170 if(!cmp) { /* found */
171 if (prev == NULL) {
172 if (hint != NULL && hint != list->front) {
173 /* we don't know the previous element */
174 hint = NULL;
175 goto redo_from_start;
177 list->front = l->next;
178 } else
179 prev->next = l->next;
180 if (l == list->back)
181 list->back = prev;
182 llist_item_put(l);
183 list->size--;
184 return prev;
186 prev = l;
187 l = l->next;
189 return prev;
192 /* computes A\B */
193 static void llist_sorted_difference_inplace(struct llist *A,
194 struct llist *B)
196 struct llist_item *hint, *b;
198 hint = NULL;
199 b = B->front;
201 while (b) {
202 hint = llist_sorted_remove(A, b->sha1, hint);
203 b = b->next;
207 static inline struct pack_list * pack_list_insert(struct pack_list **pl,
208 struct pack_list *entry)
210 struct pack_list *p = xmalloc(sizeof(struct pack_list));
211 memcpy(p, entry, sizeof(struct pack_list));
212 p->next = *pl;
213 *pl = p;
214 return p;
217 static inline size_t pack_list_size(struct pack_list *pl)
219 size_t ret = 0;
220 while(pl) {
221 ret++;
222 pl = pl->next;
224 return ret;
227 static struct pack_list * pack_list_difference(const struct pack_list *A,
228 const struct pack_list *B)
230 struct pack_list *ret;
231 const struct pack_list *pl;
233 if (A == NULL)
234 return NULL;
236 pl = B;
237 while (pl != NULL) {
238 if (A->pack == pl->pack)
239 return pack_list_difference(A->next, B);
240 pl = pl->next;
242 ret = xmalloc(sizeof(struct pack_list));
243 memcpy(ret, A, sizeof(struct pack_list));
244 ret->next = pack_list_difference(A->next, B);
245 return ret;
248 static void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
250 unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
251 const unsigned char *p1_base, *p2_base;
252 struct llist_item *p1_hint = NULL, *p2_hint = NULL;
254 p1_base = p1->pack->index_data;
255 p2_base = p2->pack->index_data;
256 p1_base += 256 * 4 + ((p1->pack->index_version < 2) ? 4 : 8);
257 p2_base += 256 * 4 + ((p2->pack->index_version < 2) ? 4 : 8);
258 p1_step = (p1->pack->index_version < 2) ? 24 : 20;
259 p2_step = (p2->pack->index_version < 2) ? 24 : 20;
261 while (p1_off < p1->pack->num_objects * p1_step &&
262 p2_off < p2->pack->num_objects * p2_step)
264 int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
265 /* cmp ~ p1 - p2 */
266 if (cmp == 0) {
267 p1_hint = llist_sorted_remove(p1->unique_objects,
268 p1_base + p1_off, p1_hint);
269 p2_hint = llist_sorted_remove(p2->unique_objects,
270 p1_base + p1_off, p2_hint);
271 p1_off += p1_step;
272 p2_off += p2_step;
273 continue;
275 if (cmp < 0) { /* p1 has the object, p2 doesn't */
276 p1_off += p1_step;
277 } else { /* p2 has the object, p1 doesn't */
278 p2_off += p2_step;
283 static void pll_free(struct pll *l)
285 struct pll *old;
286 struct pack_list *opl;
288 while (l) {
289 old = l;
290 while (l->pl) {
291 opl = l->pl;
292 l->pl = opl->next;
293 free(opl);
295 l = l->next;
296 free(old);
300 /* all the permutations have to be free()d at the same time,
301 * since they refer to each other
303 static struct pll * get_permutations(struct pack_list *list, int n)
305 struct pll *subset, *ret = NULL, *new_pll = NULL, *pll;
307 if (list == NULL || pack_list_size(list) < n || n == 0)
308 return NULL;
310 if (n == 1) {
311 while (list) {
312 new_pll = xmalloc(sizeof(pll));
313 new_pll->pl = NULL;
314 pack_list_insert(&new_pll->pl, list);
315 new_pll->next = ret;
316 ret = new_pll;
317 list = list->next;
319 return ret;
322 while (list->next) {
323 subset = get_permutations(list->next, n - 1);
324 while (subset) {
325 new_pll = xmalloc(sizeof(pll));
326 new_pll->pl = subset->pl;
327 pack_list_insert(&new_pll->pl, list);
328 new_pll->next = ret;
329 ret = new_pll;
330 subset = subset->next;
332 list = list->next;
334 return ret;
337 static int is_superset(struct pack_list *pl, struct llist *list)
339 struct llist *diff;
341 diff = llist_copy(list);
343 while (pl) {
344 llist_sorted_difference_inplace(diff, pl->all_objects);
345 if (diff->size == 0) { /* we're done */
346 llist_free(diff);
347 return 1;
349 pl = pl->next;
351 llist_free(diff);
352 return 0;
355 static size_t sizeof_union(struct packed_git *p1, struct packed_git *p2)
357 size_t ret = 0;
358 unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
359 const unsigned char *p1_base, *p2_base;
361 p1_base = p1->index_data;
362 p2_base = p2->index_data;
363 p1_base += 256 * 4 + ((p1->index_version < 2) ? 4 : 8);
364 p2_base += 256 * 4 + ((p2->index_version < 2) ? 4 : 8);
365 p1_step = (p1->index_version < 2) ? 24 : 20;
366 p2_step = (p2->index_version < 2) ? 24 : 20;
368 while (p1_off < p1->num_objects * p1_step &&
369 p2_off < p2->num_objects * p2_step)
371 int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
372 /* cmp ~ p1 - p2 */
373 if (cmp == 0) {
374 ret++;
375 p1_off += p1_step;
376 p2_off += p2_step;
377 continue;
379 if (cmp < 0) { /* p1 has the object, p2 doesn't */
380 p1_off += p1_step;
381 } else { /* p2 has the object, p1 doesn't */
382 p2_off += p2_step;
385 return ret;
388 /* another O(n^2) function ... */
389 static size_t get_pack_redundancy(struct pack_list *pl)
391 struct pack_list *subset;
392 size_t ret = 0;
394 if (pl == NULL)
395 return 0;
397 while ((subset = pl->next)) {
398 while(subset) {
399 ret += sizeof_union(pl->pack, subset->pack);
400 subset = subset->next;
402 pl = pl->next;
404 return ret;
407 static inline off_t pack_set_bytecount(struct pack_list *pl)
409 off_t ret = 0;
410 while (pl) {
411 ret += pl->pack->pack_size;
412 ret += pl->pack->index_size;
413 pl = pl->next;
415 return ret;
418 static void minimize(struct pack_list **min)
420 struct pack_list *pl, *unique = NULL,
421 *non_unique = NULL, *min_perm = NULL;
422 struct pll *perm, *perm_all, *perm_ok = NULL, *new_perm;
423 struct llist *missing;
424 off_t min_perm_size = 0, perm_size;
425 int n;
427 pl = local_packs;
428 while (pl) {
429 if(pl->unique_objects->size)
430 pack_list_insert(&unique, pl);
431 else
432 pack_list_insert(&non_unique, pl);
433 pl = pl->next;
435 /* find out which objects are missing from the set of unique packs */
436 missing = llist_copy(all_objects);
437 pl = unique;
438 while (pl) {
439 llist_sorted_difference_inplace(missing, pl->all_objects);
440 pl = pl->next;
443 /* return if there are no objects missing from the unique set */
444 if (missing->size == 0) {
445 *min = unique;
446 return;
449 /* find the permutations which contain all missing objects */
450 for (n = 1; n <= pack_list_size(non_unique) && !perm_ok; n++) {
451 perm_all = perm = get_permutations(non_unique, n);
452 while (perm) {
453 if (is_superset(perm->pl, missing)) {
454 new_perm = xmalloc(sizeof(struct pll));
455 memcpy(new_perm, perm, sizeof(struct pll));
456 new_perm->next = perm_ok;
457 perm_ok = new_perm;
459 perm = perm->next;
461 if (perm_ok)
462 break;
463 pll_free(perm_all);
465 if (perm_ok == NULL)
466 die("Internal error: No complete sets found!\n");
468 /* find the permutation with the smallest size */
469 perm = perm_ok;
470 while (perm) {
471 perm_size = pack_set_bytecount(perm->pl);
472 if (!min_perm_size || min_perm_size > perm_size) {
473 min_perm_size = perm_size;
474 min_perm = perm->pl;
476 perm = perm->next;
478 *min = min_perm;
479 /* add the unique packs to the list */
480 pl = unique;
481 while(pl) {
482 pack_list_insert(min, pl);
483 pl = pl->next;
487 static void load_all_objects(void)
489 struct pack_list *pl = local_packs;
490 struct llist_item *hint, *l;
492 llist_init(&all_objects);
494 while (pl) {
495 hint = NULL;
496 l = pl->all_objects->front;
497 while (l) {
498 hint = llist_insert_sorted_unique(all_objects,
499 l->sha1, hint);
500 l = l->next;
502 pl = pl->next;
504 /* remove objects present in remote packs */
505 pl = altodb_packs;
506 while (pl) {
507 llist_sorted_difference_inplace(all_objects, pl->all_objects);
508 pl = pl->next;
512 /* this scales like O(n^2) */
513 static void cmp_local_packs(void)
515 struct pack_list *subset, *pl = local_packs;
517 while ((subset = pl)) {
518 while((subset = subset->next))
519 cmp_two_packs(pl, subset);
520 pl = pl->next;
524 static void scan_alt_odb_packs(void)
526 struct pack_list *local, *alt;
528 alt = altodb_packs;
529 while (alt) {
530 local = local_packs;
531 while (local) {
532 llist_sorted_difference_inplace(local->unique_objects,
533 alt->all_objects);
534 local = local->next;
536 llist_sorted_difference_inplace(all_objects, alt->all_objects);
537 alt = alt->next;
541 static struct pack_list * add_pack(struct packed_git *p)
543 struct pack_list l;
544 unsigned long off = 0, step;
545 const unsigned char *base;
547 if (!p->pack_local && !(alt_odb || verbose))
548 return NULL;
550 l.pack = p;
551 llist_init(&l.all_objects);
553 if (open_pack_index(p))
554 return NULL;
556 base = p->index_data;
557 base += 256 * 4 + ((p->index_version < 2) ? 4 : 8);
558 step = (p->index_version < 2) ? 24 : 20;
559 while (off < p->num_objects * step) {
560 llist_insert_back(l.all_objects, base + off);
561 off += step;
563 /* this list will be pruned in cmp_two_packs later */
564 l.unique_objects = llist_copy(l.all_objects);
565 if (p->pack_local)
566 return pack_list_insert(&local_packs, &l);
567 else
568 return pack_list_insert(&altodb_packs, &l);
571 static struct pack_list * add_pack_file(char *filename)
573 struct packed_git *p = packed_git;
575 if (strlen(filename) < 40)
576 die("Bad pack filename: %s\n", filename);
578 while (p) {
579 if (strstr(p->pack_name, filename))
580 return add_pack(p);
581 p = p->next;
583 die("Filename %s not found in packed_git\n", filename);
586 static void load_all(void)
588 struct packed_git *p = packed_git;
590 while (p) {
591 add_pack(p);
592 p = p->next;
596 int main(int argc, char **argv)
598 int i;
599 struct pack_list *min, *red, *pl;
600 struct llist *ignore;
601 unsigned char *sha1;
602 char buf[42]; /* 40 byte sha1 + \n + \0 */
604 setup_git_directory();
606 for (i = 1; i < argc; i++) {
607 const char *arg = argv[i];
608 if(!strcmp(arg, "--")) {
609 i++;
610 break;
612 if(!strcmp(arg, "--all")) {
613 load_all_packs = 1;
614 continue;
616 if(!strcmp(arg, "--verbose")) {
617 verbose = 1;
618 continue;
620 if(!strcmp(arg, "--alt-odb")) {
621 alt_odb = 1;
622 continue;
624 if(*arg == '-')
625 usage(pack_redundant_usage);
626 else
627 break;
630 prepare_packed_git();
632 if (load_all_packs)
633 load_all();
634 else
635 while (*(argv + i) != NULL)
636 add_pack_file(*(argv + i++));
638 if (local_packs == NULL)
639 die("Zero packs found!\n");
641 load_all_objects();
643 cmp_local_packs();
644 if (alt_odb)
645 scan_alt_odb_packs();
647 /* ignore objects given on stdin */
648 llist_init(&ignore);
649 if (!isatty(0)) {
650 while (fgets(buf, sizeof(buf), stdin)) {
651 sha1 = xmalloc(20);
652 if (get_sha1_hex(buf, sha1))
653 die("Bad sha1 on stdin: %s", buf);
654 llist_insert_sorted_unique(ignore, sha1, NULL);
657 llist_sorted_difference_inplace(all_objects, ignore);
658 pl = local_packs;
659 while (pl) {
660 llist_sorted_difference_inplace(pl->unique_objects, ignore);
661 pl = pl->next;
664 minimize(&min);
666 if (verbose) {
667 fprintf(stderr, "There are %lu packs available in alt-odbs.\n",
668 (unsigned long)pack_list_size(altodb_packs));
669 fprintf(stderr, "The smallest (bytewise) set of packs is:\n");
670 pl = min;
671 while (pl) {
672 fprintf(stderr, "\t%s\n", pl->pack->pack_name);
673 pl = pl->next;
675 fprintf(stderr, "containing %lu duplicate objects "
676 "with a total size of %lukb.\n",
677 (unsigned long)get_pack_redundancy(min),
678 (unsigned long)pack_set_bytecount(min)/1024);
679 fprintf(stderr, "A total of %lu unique objects were considered.\n",
680 (unsigned long)all_objects->size);
681 fprintf(stderr, "Redundant packs (with indexes):\n");
683 pl = red = pack_list_difference(local_packs, min);
684 while (pl) {
685 printf("%s\n%s\n",
686 sha1_pack_index_name(pl->pack->sha1),
687 pl->pack->pack_name);
688 pl = pl->next;
690 if (verbose)
691 fprintf(stderr, "%luMB of redundant packs in total.\n",
692 (unsigned long)pack_set_bytecount(red)/(1024*1024));
694 return 0;