Code

GIT 1.5.1.2
[git.git] / pack-redundant.c
1 /*
2 *
3 * Copyright 2005, Lukas Sandstrom <lukass@etek.chalmers.se>
4 *
5 * This file is licensed under the GPL v2.
6 *
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;
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 */
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;
38 };
40 static struct llist_item *free_nodes;
42 static inline void llist_item_put(struct llist_item *item)
43 {
44         item->next = free_nodes;
45         free_nodes = item;
46 }
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 }
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 }
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 }
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);
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;
100         }
101         new->next = NULL;
102         ret->back = new;
103         
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;
126         }
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);
147                 }
148                 if(!cmp) { /* already exists */
149                         return l;
150                 }
151                 prev = l;
152                 l = l->next;
153         }
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;
176                                 }
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;
185                 }
186                 prev = l;
187                 l = l->next;
188         }
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;
204         }
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;
223         }
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;
241         }
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         int p1_off, p2_off;
251         const unsigned char *p1_base, *p2_base;
252         struct llist_item *p1_hint = NULL, *p2_hint = NULL;
254         p1_off = p2_off = 256 * 4 + 4;
255         p1_base = p1->pack->index_data;
256         p2_base = p2->pack->index_data;
258         while (p1_off <= p1->pack->index_size - 3 * 20 &&
259                p2_off <= p2->pack->index_size - 3 * 20)
260         {
261                 int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
262                 /* cmp ~ p1 - p2 */
263                 if (cmp == 0) {
264                         p1_hint = llist_sorted_remove(p1->unique_objects,
265                                         p1_base + p1_off, p1_hint);
266                         p2_hint = llist_sorted_remove(p2->unique_objects,
267                                         p1_base + p1_off, p2_hint);
268                         p1_off+=24;
269                         p2_off+=24;
270                         continue;
271                 }
272                 if (cmp < 0) { /* p1 has the object, p2 doesn't */
273                         p1_off+=24;
274                 } else { /* p2 has the object, p1 doesn't */
275                         p2_off+=24;
276                 }
277         }
280 static void pll_free(struct pll *l)
282         struct pll *old;
283         struct pack_list *opl;
285         while (l) {
286                 old = l;
287                 while (l->pl) {
288                         opl = l->pl;
289                         l->pl = opl->next;
290                         free(opl);
291                 }
292                 l = l->next;
293                 free(old);
294         }
297 /* all the permutations have to be free()d at the same time,
298  * since they refer to each other
299  */
300 static struct pll * get_permutations(struct pack_list *list, int n)
302         struct pll *subset, *ret = NULL, *new_pll = NULL, *pll;
304         if (list == NULL || pack_list_size(list) < n || n == 0)
305                 return NULL;
307         if (n == 1) {
308                 while (list) {
309                         new_pll = xmalloc(sizeof(pll));
310                         new_pll->pl = NULL;
311                         pack_list_insert(&new_pll->pl, list);
312                         new_pll->next = ret;
313                         ret = new_pll;
314                         list = list->next;
315                 }
316                 return ret;
317         }
319         while (list->next) {
320                 subset = get_permutations(list->next, n - 1);
321                 while (subset) {
322                         new_pll = xmalloc(sizeof(pll));
323                         new_pll->pl = subset->pl;
324                         pack_list_insert(&new_pll->pl, list);
325                         new_pll->next = ret;
326                         ret = new_pll;
327                         subset = subset->next;
328                 }
329                 list = list->next;
330         }
331         return ret;
334 static int is_superset(struct pack_list *pl, struct llist *list)
336         struct llist *diff;
338         diff = llist_copy(list);
340         while (pl) {
341                 llist_sorted_difference_inplace(diff, pl->all_objects);
342                 if (diff->size == 0) { /* we're done */
343                         llist_free(diff);
344                         return 1;
345                 }
346                 pl = pl->next;
347         }
348         llist_free(diff);
349         return 0;
352 static size_t sizeof_union(struct packed_git *p1, struct packed_git *p2)
354         size_t ret = 0;
355         int p1_off, p2_off;
356         const unsigned char *p1_base, *p2_base;
358         p1_off = p2_off = 256 * 4 + 4;
359         p1_base = p1->index_data;
360         p2_base = p2->index_data;
362         while (p1_off <= p1->index_size - 3 * 20 &&
363                p2_off <= p2->index_size - 3 * 20)
364         {
365                 int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
366                 /* cmp ~ p1 - p2 */
367                 if (cmp == 0) {
368                         ret++;
369                         p1_off+=24;
370                         p2_off+=24;
371                         continue;
372                 }
373                 if (cmp < 0) { /* p1 has the object, p2 doesn't */
374                         p1_off+=24;
375                 } else { /* p2 has the object, p1 doesn't */
376                         p2_off+=24;
377                 }
378         }
379         return ret;
382 /* another O(n^2) function ... */
383 static size_t get_pack_redundancy(struct pack_list *pl)
385         struct pack_list *subset;
386         size_t ret = 0;
388         if (pl == NULL)
389                 return 0;
391         while ((subset = pl->next)) {
392                 while(subset) {
393                         ret += sizeof_union(pl->pack, subset->pack);
394                         subset = subset->next;
395                 }
396                 pl = pl->next;
397         }
398         return ret;
401 static inline off_t pack_set_bytecount(struct pack_list *pl)
403         off_t ret = 0;
404         while (pl) {
405                 ret += pl->pack->pack_size;
406                 ret += pl->pack->index_size;
407                 pl = pl->next;
408         }
409         return ret;
412 static void minimize(struct pack_list **min)
414         struct pack_list *pl, *unique = NULL,
415                 *non_unique = NULL, *min_perm = NULL;
416         struct pll *perm, *perm_all, *perm_ok = NULL, *new_perm;
417         struct llist *missing;
418         off_t min_perm_size = 0, perm_size;
419         int n;
421         pl = local_packs;
422         while (pl) {
423                 if(pl->unique_objects->size)
424                         pack_list_insert(&unique, pl);
425                 else
426                         pack_list_insert(&non_unique, pl);
427                 pl = pl->next;
428         }
429         /* find out which objects are missing from the set of unique packs */
430         missing = llist_copy(all_objects);
431         pl = unique;
432         while (pl) {
433                 llist_sorted_difference_inplace(missing, pl->all_objects);
434                 pl = pl->next;
435         }
437         /* return if there are no objects missing from the unique set */
438         if (missing->size == 0) {
439                 *min = unique;
440                 return;
441         }
443         /* find the permutations which contain all missing objects */
444         for (n = 1; n <= pack_list_size(non_unique) && !perm_ok; n++) {
445                 perm_all = perm = get_permutations(non_unique, n);
446                 while (perm) {
447                         if (is_superset(perm->pl, missing)) {
448                                 new_perm = xmalloc(sizeof(struct pll));
449                                 memcpy(new_perm, perm, sizeof(struct pll));
450                                 new_perm->next = perm_ok;
451                                 perm_ok = new_perm;
452                         }
453                         perm = perm->next;
454                 }
455                 if (perm_ok)
456                         break;
457                 pll_free(perm_all);
458         }
459         if (perm_ok == NULL)
460                 die("Internal error: No complete sets found!\n");
462         /* find the permutation with the smallest size */
463         perm = perm_ok;
464         while (perm) {
465                 perm_size = pack_set_bytecount(perm->pl);
466                 if (!min_perm_size || min_perm_size > perm_size) {
467                         min_perm_size = perm_size;
468                         min_perm = perm->pl;
469                 }
470                 perm = perm->next;
471         }
472         *min = min_perm;
473         /* add the unique packs to the list */
474         pl = unique;
475         while(pl) {
476                 pack_list_insert(min, pl);
477                 pl = pl->next;
478         }
481 static void load_all_objects(void)
483         struct pack_list *pl = local_packs;
484         struct llist_item *hint, *l;
486         llist_init(&all_objects);
488         while (pl) {
489                 hint = NULL;
490                 l = pl->all_objects->front;
491                 while (l) {
492                         hint = llist_insert_sorted_unique(all_objects,
493                                                           l->sha1, hint);
494                         l = l->next;
495                 }
496                 pl = pl->next;
497         }
498         /* remove objects present in remote packs */
499         pl = altodb_packs;
500         while (pl) {
501                 llist_sorted_difference_inplace(all_objects, pl->all_objects);
502                 pl = pl->next;
503         }
506 /* this scales like O(n^2) */
507 static void cmp_local_packs(void)
509         struct pack_list *subset, *pl = local_packs;
511         while ((subset = pl)) {
512                 while((subset = subset->next))
513                         cmp_two_packs(pl, subset);
514                 pl = pl->next;
515         }
518 static void scan_alt_odb_packs(void)
520         struct pack_list *local, *alt;
522         alt = altodb_packs;
523         while (alt) {
524                 local = local_packs;
525                 while (local) {
526                         llist_sorted_difference_inplace(local->unique_objects,
527                                                         alt->all_objects);
528                         local = local->next;
529                 }
530                 llist_sorted_difference_inplace(all_objects, alt->all_objects);
531                 alt = alt->next;
532         }
535 static struct pack_list * add_pack(struct packed_git *p)
537         struct pack_list l;
538         size_t off;
539         const unsigned char *base;
541         if (!p->pack_local && !(alt_odb || verbose))
542                 return NULL;
544         l.pack = p;
545         llist_init(&l.all_objects);
547         off = 256 * 4 + 4;
548         base = p->index_data;
549         while (off <= p->index_size - 3 * 20) {
550                 llist_insert_back(l.all_objects, base + off);
551                 off += 24;
552         }
553         /* this list will be pruned in cmp_two_packs later */
554         l.unique_objects = llist_copy(l.all_objects);
555         if (p->pack_local)
556                 return pack_list_insert(&local_packs, &l);
557         else
558                 return pack_list_insert(&altodb_packs, &l);
561 static struct pack_list * add_pack_file(char *filename)
563         struct packed_git *p = packed_git;
565         if (strlen(filename) < 40)
566                 die("Bad pack filename: %s\n", filename);
568         while (p) {
569                 if (strstr(p->pack_name, filename))
570                         return add_pack(p);
571                 p = p->next;
572         }
573         die("Filename %s not found in packed_git\n", filename);
576 static void load_all(void)
578         struct packed_git *p = packed_git;
580         while (p) {
581                 add_pack(p);
582                 p = p->next;
583         }
586 int main(int argc, char **argv)
588         int i;
589         struct pack_list *min, *red, *pl;
590         struct llist *ignore;
591         unsigned char *sha1;
592         char buf[42]; /* 40 byte sha1 + \n + \0 */
594         setup_git_directory();
596         for (i = 1; i < argc; i++) {
597                 const char *arg = argv[i];
598                 if(!strcmp(arg, "--")) {
599                         i++;
600                         break;
601                 }
602                 if(!strcmp(arg, "--all")) {
603                         load_all_packs = 1;
604                         continue;
605                 }
606                 if(!strcmp(arg, "--verbose")) {
607                         verbose = 1;
608                         continue;
609                 }
610                 if(!strcmp(arg, "--alt-odb")) {
611                         alt_odb = 1;
612                         continue;
613                 }
614                 if(*arg == '-')
615                         usage(pack_redundant_usage);
616                 else
617                         break;
618         }
620         prepare_packed_git();
622         if (load_all_packs)
623                 load_all();
624         else
625                 while (*(argv + i) != NULL)
626                         add_pack_file(*(argv + i++));
628         if (local_packs == NULL)
629                 die("Zero packs found!\n");
631         load_all_objects();
633         cmp_local_packs();
634         if (alt_odb)
635                 scan_alt_odb_packs();
637         /* ignore objects given on stdin */
638         llist_init(&ignore);
639         if (!isatty(0)) {
640                 while (fgets(buf, sizeof(buf), stdin)) {
641                         sha1 = xmalloc(20);
642                         if (get_sha1_hex(buf, sha1))
643                                 die("Bad sha1 on stdin: %s", buf);
644                         llist_insert_sorted_unique(ignore, sha1, NULL);
645                 }
646         }
647         llist_sorted_difference_inplace(all_objects, ignore);
648         pl = local_packs;
649         while (pl) {
650                 llist_sorted_difference_inplace(pl->unique_objects, ignore);
651                 pl = pl->next;
652         }
654         minimize(&min);
656         if (verbose) {
657                 fprintf(stderr, "There are %lu packs available in alt-odbs.\n",
658                         (unsigned long)pack_list_size(altodb_packs));
659                 fprintf(stderr, "The smallest (bytewise) set of packs is:\n");
660                 pl = min;
661                 while (pl) {
662                         fprintf(stderr, "\t%s\n", pl->pack->pack_name);
663                         pl = pl->next;
664                 }
665                 fprintf(stderr, "containing %lu duplicate objects "
666                                 "with a total size of %lukb.\n",
667                         (unsigned long)get_pack_redundancy(min),
668                         (unsigned long)pack_set_bytecount(min)/1024);
669                 fprintf(stderr, "A total of %lu unique objects were considered.\n",
670                         (unsigned long)all_objects->size);
671                 fprintf(stderr, "Redundant packs (with indexes):\n");
672         }
673         pl = red = pack_list_difference(local_packs, min);
674         while (pl) {
675                 printf("%s\n%s\n",
676                        sha1_pack_index_name(pl->pack->sha1),
677                        pl->pack->pack_name);
678                 pl = pl->next;
679         }
680         if (verbose)
681                 fprintf(stderr, "%luMB of redundant packs in total.\n",
682                         (unsigned long)pack_set_bytecount(red)/(1024*1024));
684         return 0;