Code

Add tests for git tag
[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;
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;
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         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)
263         {
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;
274                 }
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;
279                 }
280         }
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);
294                 }
295                 l = l->next;
296                 free(old);
297         }
300 /* all the permutations have to be free()d at the same time,
301  * since they refer to each other
302  */
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;
318                 }
319                 return ret;
320         }
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;
331                 }
332                 list = list->next;
333         }
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;
348                 }
349                 pl = pl->next;
350         }
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)
370         {
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;
378                 }
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;
383                 }
384         }
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;
401                 }
402                 pl = pl->next;
403         }
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;
414         }
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;
434         }
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;
441         }
443         /* return if there are no objects missing from the unique set */
444         if (missing->size == 0) {
445                 *min = unique;
446                 return;
447         }
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;
458                         }
459                         perm = perm->next;
460                 }
461                 if (perm_ok)
462                         break;
463                 pll_free(perm_all);
464         }
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;
475                 }
476                 perm = perm->next;
477         }
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;
484         }
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;
501                 }
502                 pl = pl->next;
503         }
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;
509         }
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;
521         }
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;
535                 }
536                 llist_sorted_difference_inplace(all_objects, alt->all_objects);
537                 alt = alt->next;
538         }
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;
562         }
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;
582         }
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;
593         }
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;
611                 }
612                 if(!strcmp(arg, "--all")) {
613                         load_all_packs = 1;
614                         continue;
615                 }
616                 if(!strcmp(arg, "--verbose")) {
617                         verbose = 1;
618                         continue;
619                 }
620                 if(!strcmp(arg, "--alt-odb")) {
621                         alt_odb = 1;
622                         continue;
623                 }
624                 if(*arg == '-')
625                         usage(pack_redundant_usage);
626                 else
627                         break;
628         }
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);
655                 }
656         }
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;
662         }
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;
674                 }
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");
682         }
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;
689         }
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;