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1 | /* | |
2 | * | |
3 | * Copyright 2005, Lukas Sandstrom <lukass@etek.chalmers.se> | |
4 | * | |
5 | * This file is licensed under the GPL v2. | |
6 | * | |
7 | */ | |
8 | ||
9 | #include "cache.h" | |
10 | ||
11 | #define BLKSIZE 512 | |
12 | ||
13 | static const char pack_redundant_usage[] = | |
14 | "git-pack-redundant [ --verbose ] [ --alt-odb ] < --all | <.pack filename> ...>"; | |
15 | ||
16 | static int load_all_packs, verbose, alt_odb; | |
17 | ||
18 | struct llist_item { | |
19 | struct llist_item *next; | |
20 | unsigned char *sha1; | |
21 | }; | |
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 */ | |
27 | ||
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; | |
34 | ||
35 | struct pll { | |
36 | struct pll *next; | |
37 | struct pack_list *pl; | |
38 | }; | |
39 | ||
40 | static struct llist_item *free_nodes; | |
41 | ||
42 | static inline void llist_item_put(struct llist_item *item) | |
43 | { | |
44 | item->next = free_nodes; | |
45 | free_nodes = item; | |
46 | } | |
47 | ||
48 | static inline struct llist_item *llist_item_get(void) | |
49 | { | |
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]); | |
59 | } | |
60 | } | |
61 | return new; | |
62 | } | |
63 | ||
64 | static void llist_free(struct llist *list) | |
65 | { | |
66 | while((list->back = list->front)) { | |
67 | list->front = list->front->next; | |
68 | llist_item_put(list->back); | |
69 | } | |
70 | free(list); | |
71 | } | |
72 | ||
73 | static inline void llist_init(struct llist **list) | |
74 | { | |
75 | *list = xmalloc(sizeof(struct llist)); | |
76 | (*list)->front = (*list)->back = NULL; | |
77 | (*list)->size = 0; | |
78 | } | |
79 | ||
80 | static struct llist * llist_copy(struct llist *list) | |
81 | { | |
82 | struct llist *ret; | |
83 | struct llist_item *new, *old, *prev; | |
84 | ||
85 | llist_init(&ret); | |
86 | ||
87 | if ((ret->size = list->size) == 0) | |
88 | return ret; | |
89 | ||
90 | new = ret->front = llist_item_get(); | |
91 | new->sha1 = list->front->sha1; | |
92 | ||
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; | |
100 | } | |
101 | new->next = NULL; | |
102 | ret->back = new; | |
103 | ||
104 | return ret; | |
105 | } | |
106 | ||
107 | static inline struct llist_item * llist_insert(struct llist *list, | |
108 | struct llist_item *after, | |
109 | unsigned char *sha1) | |
110 | { | |
111 | struct llist_item *new = llist_item_get(); | |
112 | new->sha1 = sha1; | |
113 | new->next = NULL; | |
114 | ||
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; | |
126 | } | |
127 | list->size++; | |
128 | return new; | |
129 | } | |
130 | ||
131 | static inline struct llist_item *llist_insert_back(struct llist *list, unsigned char *sha1) | |
132 | { | |
133 | return llist_insert(list, list->back, sha1); | |
134 | } | |
135 | ||
136 | static inline struct llist_item *llist_insert_sorted_unique(struct llist *list, unsigned char *sha1, struct llist_item *hint) | |
137 | { | |
138 | struct llist_item *prev = NULL, *l; | |
139 | ||
140 | l = (hint == NULL) ? list->front : hint; | |
141 | while (l) { | |
142 | int cmp = hashcmp(l->sha1, sha1); | |
143 | if (cmp > 0) { /* we insert before this entry */ | |
144 | return llist_insert(list, prev, sha1); | |
145 | } | |
146 | if(!cmp) { /* already exists */ | |
147 | return l; | |
148 | } | |
149 | prev = l; | |
150 | l = l->next; | |
151 | } | |
152 | /* insert at the end */ | |
153 | return llist_insert_back(list, sha1); | |
154 | } | |
155 | ||
156 | /* returns a pointer to an item in front of sha1 */ | |
157 | static inline struct llist_item * llist_sorted_remove(struct llist *list, const unsigned char *sha1, struct llist_item *hint) | |
158 | { | |
159 | struct llist_item *prev, *l; | |
160 | ||
161 | redo_from_start: | |
162 | l = (hint == NULL) ? list->front : hint; | |
163 | prev = NULL; | |
164 | while (l) { | |
165 | int cmp = hashcmp(l->sha1, sha1); | |
166 | if (cmp > 0) /* not in list, since sorted */ | |
167 | return prev; | |
168 | if(!cmp) { /* found */ | |
169 | if (prev == NULL) { | |
170 | if (hint != NULL && hint != list->front) { | |
171 | /* we don't know the previous element */ | |
172 | hint = NULL; | |
173 | goto redo_from_start; | |
174 | } | |
175 | list->front = l->next; | |
176 | } else | |
177 | prev->next = l->next; | |
178 | if (l == list->back) | |
179 | list->back = prev; | |
180 | llist_item_put(l); | |
181 | list->size--; | |
182 | return prev; | |
183 | } | |
184 | prev = l; | |
185 | l = l->next; | |
186 | } | |
187 | return prev; | |
188 | } | |
189 | ||
190 | /* computes A\B */ | |
191 | static void llist_sorted_difference_inplace(struct llist *A, | |
192 | struct llist *B) | |
193 | { | |
194 | struct llist_item *hint, *b; | |
195 | ||
196 | hint = NULL; | |
197 | b = B->front; | |
198 | ||
199 | while (b) { | |
200 | hint = llist_sorted_remove(A, b->sha1, hint); | |
201 | b = b->next; | |
202 | } | |
203 | } | |
204 | ||
205 | static inline struct pack_list * pack_list_insert(struct pack_list **pl, | |
206 | struct pack_list *entry) | |
207 | { | |
208 | struct pack_list *p = xmalloc(sizeof(struct pack_list)); | |
209 | memcpy(p, entry, sizeof(struct pack_list)); | |
210 | p->next = *pl; | |
211 | *pl = p; | |
212 | return p; | |
213 | } | |
214 | ||
215 | static inline size_t pack_list_size(struct pack_list *pl) | |
216 | { | |
217 | size_t ret = 0; | |
218 | while(pl) { | |
219 | ret++; | |
220 | pl = pl->next; | |
221 | } | |
222 | return ret; | |
223 | } | |
224 | ||
225 | static struct pack_list * pack_list_difference(const struct pack_list *A, | |
226 | const struct pack_list *B) | |
227 | { | |
228 | struct pack_list *ret; | |
229 | const struct pack_list *pl; | |
230 | ||
231 | if (A == NULL) | |
232 | return NULL; | |
233 | ||
234 | pl = B; | |
235 | while (pl != NULL) { | |
236 | if (A->pack == pl->pack) | |
237 | return pack_list_difference(A->next, B); | |
238 | pl = pl->next; | |
239 | } | |
240 | ret = xmalloc(sizeof(struct pack_list)); | |
241 | memcpy(ret, A, sizeof(struct pack_list)); | |
242 | ret->next = pack_list_difference(A->next, B); | |
243 | return ret; | |
244 | } | |
245 | ||
246 | static void cmp_two_packs(struct pack_list *p1, struct pack_list *p2) | |
247 | { | |
248 | int p1_off, p2_off; | |
249 | unsigned char *p1_base, *p2_base; | |
250 | struct llist_item *p1_hint = NULL, *p2_hint = NULL; | |
251 | ||
252 | p1_off = p2_off = 256 * 4 + 4; | |
253 | p1_base = (unsigned char *) p1->pack->index_base; | |
254 | p2_base = (unsigned char *) p2->pack->index_base; | |
255 | ||
256 | while (p1_off <= p1->pack->index_size - 3 * 20 && | |
257 | p2_off <= p2->pack->index_size - 3 * 20) | |
258 | { | |
259 | int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off); | |
260 | /* cmp ~ p1 - p2 */ | |
261 | if (cmp == 0) { | |
262 | p1_hint = llist_sorted_remove(p1->unique_objects, | |
263 | p1_base + p1_off, p1_hint); | |
264 | p2_hint = llist_sorted_remove(p2->unique_objects, | |
265 | p1_base + p1_off, p2_hint); | |
266 | p1_off+=24; | |
267 | p2_off+=24; | |
268 | continue; | |
269 | } | |
270 | if (cmp < 0) { /* p1 has the object, p2 doesn't */ | |
271 | p1_off+=24; | |
272 | } else { /* p2 has the object, p1 doesn't */ | |
273 | p2_off+=24; | |
274 | } | |
275 | } | |
276 | } | |
277 | ||
278 | static void pll_free(struct pll *l) | |
279 | { | |
280 | struct pll *old; | |
281 | struct pack_list *opl; | |
282 | ||
283 | while (l) { | |
284 | old = l; | |
285 | while (l->pl) { | |
286 | opl = l->pl; | |
287 | l->pl = opl->next; | |
288 | free(opl); | |
289 | } | |
290 | l = l->next; | |
291 | free(old); | |
292 | } | |
293 | } | |
294 | ||
295 | /* all the permutations have to be free()d at the same time, | |
296 | * since they refer to each other | |
297 | */ | |
298 | static struct pll * get_permutations(struct pack_list *list, int n) | |
299 | { | |
300 | struct pll *subset, *ret = NULL, *new_pll = NULL, *pll; | |
301 | ||
302 | if (list == NULL || pack_list_size(list) < n || n == 0) | |
303 | return NULL; | |
304 | ||
305 | if (n == 1) { | |
306 | while (list) { | |
307 | new_pll = xmalloc(sizeof(pll)); | |
308 | new_pll->pl = NULL; | |
309 | pack_list_insert(&new_pll->pl, list); | |
310 | new_pll->next = ret; | |
311 | ret = new_pll; | |
312 | list = list->next; | |
313 | } | |
314 | return ret; | |
315 | } | |
316 | ||
317 | while (list->next) { | |
318 | subset = get_permutations(list->next, n - 1); | |
319 | while (subset) { | |
320 | new_pll = xmalloc(sizeof(pll)); | |
321 | new_pll->pl = subset->pl; | |
322 | pack_list_insert(&new_pll->pl, list); | |
323 | new_pll->next = ret; | |
324 | ret = new_pll; | |
325 | subset = subset->next; | |
326 | } | |
327 | list = list->next; | |
328 | } | |
329 | return ret; | |
330 | } | |
331 | ||
332 | static int is_superset(struct pack_list *pl, struct llist *list) | |
333 | { | |
334 | struct llist *diff; | |
335 | ||
336 | diff = llist_copy(list); | |
337 | ||
338 | while (pl) { | |
339 | llist_sorted_difference_inplace(diff, pl->all_objects); | |
340 | if (diff->size == 0) { /* we're done */ | |
341 | llist_free(diff); | |
342 | return 1; | |
343 | } | |
344 | pl = pl->next; | |
345 | } | |
346 | llist_free(diff); | |
347 | return 0; | |
348 | } | |
349 | ||
350 | static size_t sizeof_union(struct packed_git *p1, struct packed_git *p2) | |
351 | { | |
352 | size_t ret = 0; | |
353 | int p1_off, p2_off; | |
354 | unsigned char *p1_base, *p2_base; | |
355 | ||
356 | p1_off = p2_off = 256 * 4 + 4; | |
357 | p1_base = (unsigned char *)p1->index_base; | |
358 | p2_base = (unsigned char *)p2->index_base; | |
359 | ||
360 | while (p1_off <= p1->index_size - 3 * 20 && | |
361 | p2_off <= p2->index_size - 3 * 20) | |
362 | { | |
363 | int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off); | |
364 | /* cmp ~ p1 - p2 */ | |
365 | if (cmp == 0) { | |
366 | ret++; | |
367 | p1_off+=24; | |
368 | p2_off+=24; | |
369 | continue; | |
370 | } | |
371 | if (cmp < 0) { /* p1 has the object, p2 doesn't */ | |
372 | p1_off+=24; | |
373 | } else { /* p2 has the object, p1 doesn't */ | |
374 | p2_off+=24; | |
375 | } | |
376 | } | |
377 | return ret; | |
378 | } | |
379 | ||
380 | /* another O(n^2) function ... */ | |
381 | static size_t get_pack_redundancy(struct pack_list *pl) | |
382 | { | |
383 | struct pack_list *subset; | |
384 | size_t ret = 0; | |
385 | ||
386 | if (pl == NULL) | |
387 | return 0; | |
388 | ||
389 | while ((subset = pl->next)) { | |
390 | while(subset) { | |
391 | ret += sizeof_union(pl->pack, subset->pack); | |
392 | subset = subset->next; | |
393 | } | |
394 | pl = pl->next; | |
395 | } | |
396 | return ret; | |
397 | } | |
398 | ||
399 | static inline size_t pack_set_bytecount(struct pack_list *pl) | |
400 | { | |
401 | size_t ret = 0; | |
402 | while (pl) { | |
403 | ret += pl->pack->pack_size; | |
404 | ret += pl->pack->index_size; | |
405 | pl = pl->next; | |
406 | } | |
407 | return ret; | |
408 | } | |
409 | ||
410 | static void minimize(struct pack_list **min) | |
411 | { | |
412 | struct pack_list *pl, *unique = NULL, | |
413 | *non_unique = NULL, *min_perm = NULL; | |
414 | struct pll *perm, *perm_all, *perm_ok = NULL, *new_perm; | |
415 | struct llist *missing; | |
416 | size_t min_perm_size = (size_t)-1, perm_size; | |
417 | int n; | |
418 | ||
419 | pl = local_packs; | |
420 | while (pl) { | |
421 | if(pl->unique_objects->size) | |
422 | pack_list_insert(&unique, pl); | |
423 | else | |
424 | pack_list_insert(&non_unique, pl); | |
425 | pl = pl->next; | |
426 | } | |
427 | /* find out which objects are missing from the set of unique packs */ | |
428 | missing = llist_copy(all_objects); | |
429 | pl = unique; | |
430 | while (pl) { | |
431 | llist_sorted_difference_inplace(missing, pl->all_objects); | |
432 | pl = pl->next; | |
433 | } | |
434 | ||
435 | /* return if there are no objects missing from the unique set */ | |
436 | if (missing->size == 0) { | |
437 | *min = unique; | |
438 | return; | |
439 | } | |
440 | ||
441 | /* find the permutations which contain all missing objects */ | |
442 | for (n = 1; n <= pack_list_size(non_unique) && !perm_ok; n++) { | |
443 | perm_all = perm = get_permutations(non_unique, n); | |
444 | while (perm) { | |
445 | if (is_superset(perm->pl, missing)) { | |
446 | new_perm = xmalloc(sizeof(struct pll)); | |
447 | memcpy(new_perm, perm, sizeof(struct pll)); | |
448 | new_perm->next = perm_ok; | |
449 | perm_ok = new_perm; | |
450 | } | |
451 | perm = perm->next; | |
452 | } | |
453 | if (perm_ok) | |
454 | break; | |
455 | pll_free(perm_all); | |
456 | } | |
457 | if (perm_ok == NULL) | |
458 | die("Internal error: No complete sets found!\n"); | |
459 | ||
460 | /* find the permutation with the smallest size */ | |
461 | perm = perm_ok; | |
462 | while (perm) { | |
463 | perm_size = pack_set_bytecount(perm->pl); | |
464 | if (min_perm_size > perm_size) { | |
465 | min_perm_size = perm_size; | |
466 | min_perm = perm->pl; | |
467 | } | |
468 | perm = perm->next; | |
469 | } | |
470 | *min = min_perm; | |
471 | /* add the unique packs to the list */ | |
472 | pl = unique; | |
473 | while(pl) { | |
474 | pack_list_insert(min, pl); | |
475 | pl = pl->next; | |
476 | } | |
477 | } | |
478 | ||
479 | static void load_all_objects(void) | |
480 | { | |
481 | struct pack_list *pl = local_packs; | |
482 | struct llist_item *hint, *l; | |
483 | ||
484 | llist_init(&all_objects); | |
485 | ||
486 | while (pl) { | |
487 | hint = NULL; | |
488 | l = pl->all_objects->front; | |
489 | while (l) { | |
490 | hint = llist_insert_sorted_unique(all_objects, | |
491 | l->sha1, hint); | |
492 | l = l->next; | |
493 | } | |
494 | pl = pl->next; | |
495 | } | |
496 | /* remove objects present in remote packs */ | |
497 | pl = altodb_packs; | |
498 | while (pl) { | |
499 | llist_sorted_difference_inplace(all_objects, pl->all_objects); | |
500 | pl = pl->next; | |
501 | } | |
502 | } | |
503 | ||
504 | /* this scales like O(n^2) */ | |
505 | static void cmp_local_packs(void) | |
506 | { | |
507 | struct pack_list *subset, *pl = local_packs; | |
508 | ||
509 | while ((subset = pl)) { | |
510 | while((subset = subset->next)) | |
511 | cmp_two_packs(pl, subset); | |
512 | pl = pl->next; | |
513 | } | |
514 | } | |
515 | ||
516 | static void scan_alt_odb_packs(void) | |
517 | { | |
518 | struct pack_list *local, *alt; | |
519 | ||
520 | alt = altodb_packs; | |
521 | while (alt) { | |
522 | local = local_packs; | |
523 | while (local) { | |
524 | llist_sorted_difference_inplace(local->unique_objects, | |
525 | alt->all_objects); | |
526 | local = local->next; | |
527 | } | |
528 | llist_sorted_difference_inplace(all_objects, alt->all_objects); | |
529 | alt = alt->next; | |
530 | } | |
531 | } | |
532 | ||
533 | static struct pack_list * add_pack(struct packed_git *p) | |
534 | { | |
535 | struct pack_list l; | |
536 | size_t off; | |
537 | unsigned char *base; | |
538 | ||
539 | if (!p->pack_local && !(alt_odb || verbose)) | |
540 | return NULL; | |
541 | ||
542 | l.pack = p; | |
543 | llist_init(&l.all_objects); | |
544 | ||
545 | off = 256 * 4 + 4; | |
546 | base = (unsigned char *)p->index_base; | |
547 | while (off <= p->index_size - 3 * 20) { | |
548 | llist_insert_back(l.all_objects, base + off); | |
549 | off += 24; | |
550 | } | |
551 | /* this list will be pruned in cmp_two_packs later */ | |
552 | l.unique_objects = llist_copy(l.all_objects); | |
553 | if (p->pack_local) | |
554 | return pack_list_insert(&local_packs, &l); | |
555 | else | |
556 | return pack_list_insert(&altodb_packs, &l); | |
557 | } | |
558 | ||
559 | static struct pack_list * add_pack_file(char *filename) | |
560 | { | |
561 | struct packed_git *p = packed_git; | |
562 | ||
563 | if (strlen(filename) < 40) | |
564 | die("Bad pack filename: %s\n", filename); | |
565 | ||
566 | while (p) { | |
567 | if (strstr(p->pack_name, filename)) | |
568 | return add_pack(p); | |
569 | p = p->next; | |
570 | } | |
571 | die("Filename %s not found in packed_git\n", filename); | |
572 | } | |
573 | ||
574 | static void load_all(void) | |
575 | { | |
576 | struct packed_git *p = packed_git; | |
577 | ||
578 | while (p) { | |
579 | add_pack(p); | |
580 | p = p->next; | |
581 | } | |
582 | } | |
583 | ||
584 | int main(int argc, char **argv) | |
585 | { | |
586 | int i; | |
587 | struct pack_list *min, *red, *pl; | |
588 | struct llist *ignore; | |
589 | unsigned char *sha1; | |
590 | char buf[42]; /* 40 byte sha1 + \n + \0 */ | |
591 | ||
592 | setup_git_directory(); | |
593 | ||
594 | for (i = 1; i < argc; i++) { | |
595 | const char *arg = argv[i]; | |
596 | if(!strcmp(arg, "--")) { | |
597 | i++; | |
598 | break; | |
599 | } | |
600 | if(!strcmp(arg, "--all")) { | |
601 | load_all_packs = 1; | |
602 | continue; | |
603 | } | |
604 | if(!strcmp(arg, "--verbose")) { | |
605 | verbose = 1; | |
606 | continue; | |
607 | } | |
608 | if(!strcmp(arg, "--alt-odb")) { | |
609 | alt_odb = 1; | |
610 | continue; | |
611 | } | |
612 | if(*arg == '-') | |
613 | usage(pack_redundant_usage); | |
614 | else | |
615 | break; | |
616 | } | |
617 | ||
618 | prepare_packed_git(); | |
619 | ||
620 | if (load_all_packs) | |
621 | load_all(); | |
622 | else | |
623 | while (*(argv + i) != NULL) | |
624 | add_pack_file(*(argv + i++)); | |
625 | ||
626 | if (local_packs == NULL) | |
627 | die("Zero packs found!\n"); | |
628 | ||
629 | load_all_objects(); | |
630 | ||
631 | cmp_local_packs(); | |
632 | if (alt_odb) | |
633 | scan_alt_odb_packs(); | |
634 | ||
635 | /* ignore objects given on stdin */ | |
636 | llist_init(&ignore); | |
637 | if (!isatty(0)) { | |
638 | while (fgets(buf, sizeof(buf), stdin)) { | |
639 | sha1 = xmalloc(20); | |
640 | if (get_sha1_hex(buf, sha1)) | |
641 | die("Bad sha1 on stdin: %s", buf); | |
642 | llist_insert_sorted_unique(ignore, sha1, NULL); | |
643 | } | |
644 | } | |
645 | llist_sorted_difference_inplace(all_objects, ignore); | |
646 | pl = local_packs; | |
647 | while (pl) { | |
648 | llist_sorted_difference_inplace(pl->unique_objects, ignore); | |
649 | pl = pl->next; | |
650 | } | |
651 | ||
652 | minimize(&min); | |
653 | ||
654 | if (verbose) { | |
655 | fprintf(stderr, "There are %lu packs available in alt-odbs.\n", | |
656 | (unsigned long)pack_list_size(altodb_packs)); | |
657 | fprintf(stderr, "The smallest (bytewise) set of packs is:\n"); | |
658 | pl = min; | |
659 | while (pl) { | |
660 | fprintf(stderr, "\t%s\n", pl->pack->pack_name); | |
661 | pl = pl->next; | |
662 | } | |
663 | fprintf(stderr, "containing %lu duplicate objects " | |
664 | "with a total size of %lukb.\n", | |
665 | (unsigned long)get_pack_redundancy(min), | |
666 | (unsigned long)pack_set_bytecount(min)/1024); | |
667 | fprintf(stderr, "A total of %lu unique objects were considered.\n", | |
668 | (unsigned long)all_objects->size); | |
669 | fprintf(stderr, "Redundant packs (with indexes):\n"); | |
670 | } | |
671 | pl = red = pack_list_difference(local_packs, min); | |
672 | while (pl) { | |
673 | printf("%s\n%s\n", | |
674 | sha1_pack_index_name(pl->pack->sha1), | |
675 | pl->pack->pack_name); | |
676 | pl = pl->next; | |
677 | } | |
678 | if (verbose) | |
679 | fprintf(stderr, "%luMB of redundant packs in total.\n", | |
680 | (unsigned long)pack_set_bytecount(red)/(1024*1024)); | |
681 | ||
682 | return 0; | |
683 | } |