builtin/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 */
   8
   9 #include "builtin.h"
  10 #include "repository.h"
  11 #include "packfile.h"
  12 #include "object-store.h"
  13
  14 #define BLKSIZE 512
  15
  16 static const char pack_redundant_usage[] =
  17 "git pack-redundant [--verbose] [--alt-odb] (--all | <filename.pack>...)";
  18
  19 static int load_all_packs, verbose, alt_odb;
  20
  21 struct llist_item {
  22         struct llist_item *next;
  23         const struct object_id *oid;
  24 };
  25 static struct llist {
  26         struct llist_item *front;
  27         struct llist_item *back;
  28         size_t size;
  29 } *all_objects; /* all objects which must be present in local packfiles */
  30
  31 static struct pack_list {
  32         struct pack_list *next;
  33         struct packed_git *pack;
  34         struct llist *unique_objects;
  35         struct llist *remaining_objects;
  36         size_t all_objects_size;
  37 } *local_packs = NULL, *altodb_packs = NULL;
  38
  39 static struct llist_item *free_nodes;
  40
  41 static inline void llist_item_put(struct llist_item *item)
  42 {
  43         item->next = free_nodes;
  44         free_nodes = item;
  45 }
  46
  47 static inline struct llist_item *llist_item_get(void)
  48 {
  49         struct llist_item *new_item;
  50         if ( free_nodes ) {
  51                 new_item = free_nodes;
  52                 free_nodes = free_nodes->next;
  53         } else {
  54                 int i = 1;
  55                 ALLOC_ARRAY(new_item, BLKSIZE);
  56                 for (; i < BLKSIZE; i++)
  57                         llist_item_put(&new_item[i]);
  58         }
  59         return new_item;
  60 }
  61
  62 static inline void llist_init(struct llist **list)
  63 {
  64         *list = xmalloc(sizeof(struct llist));
  65         (*list)->front = (*list)->back = NULL;
  66         (*list)->size = 0;
  67 }
  68
  69 static struct llist * llist_copy(struct llist *list)
  70 {
  71         struct llist *ret;
  72         struct llist_item *new_item, *old_item, *prev;
  73
  74         llist_init(&ret);
  75
  76         if ((ret->size = list->size) == 0)
  77                 return ret;
  78
  79         new_item = ret->front = llist_item_get();
  80         new_item->oid = list->front->oid;
  81
  82         old_item = list->front->next;
  83         while (old_item) {
  84                 prev = new_item;
  85                 new_item = llist_item_get();
  86                 prev->next = new_item;
  87                 new_item->oid = old_item->oid;
  88                 old_item = old_item->next;
  89         }
  90         new_item->next = NULL;
  91         ret->back = new_item;
  92
  93         return ret;
  94 }
  95
  96 static inline struct llist_item *llist_insert(struct llist *list,
  97                                               struct llist_item *after,
  98                                               const struct object_id *oid)
  99 {
 100         struct llist_item *new_item = llist_item_get();
 101         new_item->oid = oid;
 102         new_item->next = NULL;
 103
 104         if (after != NULL) {
 105                 new_item->next = after->next;
 106                 after->next = new_item;
 107                 if (after == list->back)
 108                         list->back = new_item;
 109         } else {/* insert in front */
 110                 if (list->size == 0)
 111                         list->back = new_item;
 112                 else
 113                         new_item->next = list->front;
 114                 list->front = new_item;
 115         }
 116         list->size++;
 117         return new_item;
 118 }
 119
 120 static inline struct llist_item *llist_insert_back(struct llist *list,
 121                                                    const struct object_id *oid)
 122 {
 123         return llist_insert(list, list->back, oid);
 124 }
 125
 126 static inline struct llist_item *llist_insert_sorted_unique(struct llist *list,
 127                         const struct object_id *oid, struct llist_item *hint)
 128 {
 129         struct llist_item *prev = NULL, *l;
 130
 131         l = (hint == NULL) ? list->front : hint;
 132         while (l) {
 133                 int cmp = oidcmp(l->oid, oid);
 134                 if (cmp > 0) { /* we insert before this entry */
 135                         return llist_insert(list, prev, oid);
 136                 }
 137                 if (!cmp) { /* already exists */
 138                         return l;
 139                 }
 140                 prev = l;
 141                 l = l->next;
 142         }
 143         /* insert at the end */
 144         return llist_insert_back(list, oid);
 145 }
 146
 147 /* returns a pointer to an item in front of sha1 */
 148 static inline struct llist_item * llist_sorted_remove(struct llist *list, const struct object_id *oid, struct llist_item *hint)
 149 {
 150         struct llist_item *prev, *l;
 151
 152 redo_from_start:
 153         l = (hint == NULL) ? list->front : hint;
 154         prev = NULL;
 155         while (l) {
 156                 const int cmp = oidcmp(l->oid, oid);
 157                 if (cmp > 0) /* not in list, since sorted */
 158                         return prev;
 159                 if (!cmp) { /* found */
 160                         if (prev == NULL) {
 161                                 if (hint != NULL && hint != list->front) {
 162                                         /* we don't know the previous element */
 163                                         hint = NULL;
 164                                         goto redo_from_start;
 165                                 }
 166                                 list->front = l->next;
 167                         } else
 168                                 prev->next = l->next;
 169                         if (l == list->back)
 170                                 list->back = prev;
 171                         llist_item_put(l);
 172                         list->size--;
 173                         return prev;
 174                 }
 175                 prev = l;
 176                 l = l->next;
 177         }
 178         return prev;
 179 }
 180
 181 /* computes A\B */
 182 static void llist_sorted_difference_inplace(struct llist *A,
 183                                      struct llist *B)
 184 {
 185         struct llist_item *hint, *b;
 186
 187         hint = NULL;
 188         b = B->front;
 189
 190         while (b) {
 191                 hint = llist_sorted_remove(A, b->oid, hint);
 192                 b = b->next;
 193         }
 194 }
 195
 196 static inline struct pack_list * pack_list_insert(struct pack_list **pl,
 197                                            struct pack_list *entry)
 198 {
 199         struct pack_list *p = xmalloc(sizeof(struct pack_list));
 200         memcpy(p, entry, sizeof(struct pack_list));
 201         p->next = *pl;
 202         *pl = p;
 203         return p;
 204 }
 205
 206 static inline size_t pack_list_size(struct pack_list *pl)
 207 {
 208         size_t ret = 0;
 209         while (pl) {
 210                 ret++;
 211                 pl = pl->next;
 212         }
 213         return ret;
 214 }
 215
 216 static struct pack_list * pack_list_difference(const struct pack_list *A,
 217                                                const struct pack_list *B)
 218 {
 219         struct pack_list *ret;
 220         const struct pack_list *pl;
 221
 222         if (A == NULL)
 223                 return NULL;
 224
 225         pl = B;
 226         while (pl != NULL) {
 227                 if (A->pack == pl->pack)
 228                         return pack_list_difference(A->next, B);
 229                 pl = pl->next;
 230         }
 231         ret = xmalloc(sizeof(struct pack_list));
 232         memcpy(ret, A, sizeof(struct pack_list));
 233         ret->next = pack_list_difference(A->next, B);
 234         return ret;
 235 }
 236
 237 static void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
 238 {
 239         size_t p1_off = 0, p2_off = 0, p1_step, p2_step;
 240         const unsigned char *p1_base, *p2_base;
 241         struct llist_item *p1_hint = NULL, *p2_hint = NULL;
 242         const unsigned int hashsz = the_hash_algo->rawsz;
 243
 244         if (!p1->unique_objects)
 245                 p1->unique_objects = llist_copy(p1->remaining_objects);
 246         if (!p2->unique_objects)
 247                 p2->unique_objects = llist_copy(p2->remaining_objects);
 248
 249         p1_base = p1->pack->index_data;
 250         p2_base = p2->pack->index_data;
 251         p1_base += 256 * 4 + ((p1->pack->index_version < 2) ? 4 : 8);
 252         p2_base += 256 * 4 + ((p2->pack->index_version < 2) ? 4 : 8);
 253         p1_step = hashsz + ((p1->pack->index_version < 2) ? 4 : 0);
 254         p2_step = hashsz + ((p2->pack->index_version < 2) ? 4 : 0);
 255
 256         while (p1_off < p1->pack->num_objects * p1_step &&
 257                p2_off < p2->pack->num_objects * p2_step)
 258         {
 259                 const 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                                         (const struct object_id *)(p1_base + p1_off),
 264                                         p1_hint);
 265                         p2_hint = llist_sorted_remove(p2->unique_objects,
 266                                         (const struct object_id *)(p1_base + p1_off),
 267                                         p2_hint);
 268                         p1_off += p1_step;
 269                         p2_off += p2_step;
 270                         continue;
 271                 }
 272                 if (cmp < 0) { /* p1 has the object, p2 doesn't */
 273                         p1_off += p1_step;
 274                 } else { /* p2 has the object, p1 doesn't */
 275                         p2_off += p2_step;
 276                 }
 277         }
 278 }
 279
 280 static size_t sizeof_union(struct packed_git *p1, struct packed_git *p2)
 281 {
 282         size_t ret = 0;
 283         size_t p1_off = 0, p2_off = 0, p1_step, p2_step;
 284         const unsigned char *p1_base, *p2_base;
 285         const unsigned int hashsz = the_hash_algo->rawsz;
 286
 287         p1_base = p1->index_data;
 288         p2_base = p2->index_data;
 289         p1_base += 256 * 4 + ((p1->index_version < 2) ? 4 : 8);
 290         p2_base += 256 * 4 + ((p2->index_version < 2) ? 4 : 8);
 291         p1_step = hashsz + ((p1->index_version < 2) ? 4 : 0);
 292         p2_step = hashsz + ((p2->index_version < 2) ? 4 : 0);
 293
 294         while (p1_off < p1->num_objects * p1_step &&
 295                p2_off < p2->num_objects * p2_step)
 296         {
 297                 int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
 298                 /* cmp ~ p1 - p2 */
 299                 if (cmp == 0) {
 300                         ret++;
 301                         p1_off += p1_step;
 302                         p2_off += p2_step;
 303                         continue;
 304                 }
 305                 if (cmp < 0) { /* p1 has the object, p2 doesn't */
 306                         p1_off += p1_step;
 307                 } else { /* p2 has the object, p1 doesn't */
 308                         p2_off += p2_step;
 309                 }
 310         }
 311         return ret;
 312 }
 313
 314 /* another O(n^2) function ... */
 315 static size_t get_pack_redundancy(struct pack_list *pl)
 316 {
 317         struct pack_list *subset;
 318         size_t ret = 0;
 319
 320         if (pl == NULL)
 321                 return 0;
 322
 323         while ((subset = pl->next)) {
 324                 while (subset) {
 325                         ret += sizeof_union(pl->pack, subset->pack);
 326                         subset = subset->next;
 327                 }
 328                 pl = pl->next;
 329         }
 330         return ret;
 331 }
 332
 333 static inline off_t pack_set_bytecount(struct pack_list *pl)
 334 {
 335         off_t ret = 0;
 336         while (pl) {
 337                 ret += pl->pack->pack_size;
 338                 ret += pl->pack->index_size;
 339                 pl = pl->next;
 340         }
 341         return ret;
 342 }
 343
 344 static int cmp_remaining_objects(const void *a, const void *b)
 345 {
 346         struct pack_list *pl_a = *((struct pack_list **)a);
 347         struct pack_list *pl_b = *((struct pack_list **)b);
 348
 349         if (pl_a->remaining_objects->size == pl_b->remaining_objects->size) {
 350                 /* have the same remaining_objects, big pack first */
 351                 if (pl_a->all_objects_size == pl_b->all_objects_size)
 352                         return 0;
 353                 else if (pl_a->all_objects_size < pl_b->all_objects_size)
 354                         return 1;
 355                 else
 356                         return -1;
 357         } else if (pl_a->remaining_objects->size < pl_b->remaining_objects->size) {
 358                 /* sort by remaining objects, more objects first */
 359                 return 1;
 360         } else {
 361                 return -1;
 362         }
 363 }
 364
 365 /* Sort pack_list, greater size of remaining_objects first */
 366 static void sort_pack_list(struct pack_list **pl)
 367 {
 368         struct pack_list **ary, *p;
 369         int i;
 370         size_t n = pack_list_size(*pl);
 371
 372         if (n < 2)
 373                 return;
 374
 375         /* prepare an array of packed_list for easier sorting */
 376         ary = xcalloc(n, sizeof(struct pack_list *));
 377         for (n = 0, p = *pl; p; p = p->next)
 378                 ary[n++] = p;
 379
 380         QSORT(ary, n, cmp_remaining_objects);
 381
 382         /* link them back again */
 383         for (i = 0; i < n - 1; i++)
 384                 ary[i]->next = ary[i + 1];
 385         ary[n - 1]->next = NULL;
 386         *pl = ary[0];
 387
 388         free(ary);
 389 }
 390
 391
 392 static void minimize(struct pack_list **min)
 393 {
 394         struct pack_list *pl, *unique = NULL, *non_unique = NULL;
 395         struct llist *missing, *unique_pack_objects;
 396
 397         pl = local_packs;
 398         while (pl) {
 399                 if (pl->unique_objects->size)
 400                         pack_list_insert(&unique, pl);
 401                 else
 402                         pack_list_insert(&non_unique, pl);
 403                 pl = pl->next;
 404         }
 405         /* find out which objects are missing from the set of unique packs */
 406         missing = llist_copy(all_objects);
 407         pl = unique;
 408         while (pl) {
 409                 llist_sorted_difference_inplace(missing, pl->remaining_objects);
 410                 pl = pl->next;
 411         }
 412
 413         *min = unique;
 414
 415         /* return if there are no objects missing from the unique set */
 416         if (missing->size == 0) {
 417                 free(missing);
 418                 return;
 419         }
 420
 421         unique_pack_objects = llist_copy(all_objects);
 422         llist_sorted_difference_inplace(unique_pack_objects, missing);
 423
 424         /* remove unique pack objects from the non_unique packs */
 425         pl = non_unique;
 426         while (pl) {
 427                 llist_sorted_difference_inplace(pl->remaining_objects, unique_pack_objects);
 428                 pl = pl->next;
 429         }
 430
 431         while (non_unique) {
 432                 /* sort the non_unique packs, greater size of remaining_objects first */
 433                 sort_pack_list(&non_unique);
 434                 if (non_unique->remaining_objects->size == 0)
 435                         break;
 436
 437                 pack_list_insert(min, non_unique);
 438
 439                 for (pl = non_unique->next; pl && pl->remaining_objects->size > 0;  pl = pl->next)
 440                         llist_sorted_difference_inplace(pl->remaining_objects, non_unique->remaining_objects);
 441
 442                 non_unique = non_unique->next;
 443         }
 444 }
 445
 446 static void load_all_objects(void)
 447 {
 448         struct pack_list *pl = local_packs;
 449         struct llist_item *hint, *l;
 450
 451         llist_init(&all_objects);
 452
 453         while (pl) {
 454                 hint = NULL;
 455                 l = pl->remaining_objects->front;
 456                 while (l) {
 457                         hint = llist_insert_sorted_unique(all_objects,
 458                                                           l->oid, hint);
 459                         l = l->next;
 460                 }
 461                 pl = pl->next;
 462         }
 463         /* remove objects present in remote packs */
 464         pl = altodb_packs;
 465         while (pl) {
 466                 llist_sorted_difference_inplace(all_objects, pl->remaining_objects);
 467                 pl = pl->next;
 468         }
 469 }
 470
 471 /* this scales like O(n^2) */
 472 static void cmp_local_packs(void)
 473 {
 474         struct pack_list *subset, *pl = local_packs;
 475
 476         /* only one packfile */
 477         if (!pl->next) {
 478                 llist_init(&pl->unique_objects);
 479                 return;
 480         }
 481
 482         while ((subset = pl)) {
 483                 while ((subset = subset->next))
 484                         cmp_two_packs(pl, subset);
 485                 pl = pl->next;
 486         }
 487 }
 488
 489 static void scan_alt_odb_packs(void)
 490 {
 491         struct pack_list *local, *alt;
 492
 493         alt = altodb_packs;
 494         while (alt) {
 495                 local = local_packs;
 496                 while (local) {
 497                         llist_sorted_difference_inplace(local->remaining_objects,
 498                                                         alt->remaining_objects);
 499                         local = local->next;
 500                 }
 501                 alt = alt->next;
 502         }
 503 }
 504
 505 static struct pack_list * add_pack(struct packed_git *p)
 506 {
 507         struct pack_list l;
 508         size_t off = 0, step;
 509         const unsigned char *base;
 510
 511         if (!p->pack_local && !(alt_odb || verbose))
 512                 return NULL;
 513
 514         l.pack = p;
 515         llist_init(&l.remaining_objects);
 516
 517         if (open_pack_index(p))
 518                 return NULL;
 519
 520         base = p->index_data;
 521         base += 256 * 4 + ((p->index_version < 2) ? 4 : 8);
 522         step = the_hash_algo->rawsz + ((p->index_version < 2) ? 4 : 0);
 523         while (off < p->num_objects * step) {
 524                 llist_insert_back(l.remaining_objects, (const struct object_id *)(base + off));
 525                 off += step;
 526         }
 527         l.all_objects_size = l.remaining_objects->size;
 528         l.unique_objects = NULL;
 529         if (p->pack_local)
 530                 return pack_list_insert(&local_packs, &l);
 531         else
 532                 return pack_list_insert(&altodb_packs, &l);
 533 }
 534
 535 static struct pack_list * add_pack_file(const char *filename)
 536 {
 537         struct packed_git *p = get_all_packs(the_repository);
 538
 539         if (strlen(filename) < 40)
 540                 die("Bad pack filename: %s", filename);
 541
 542         while (p) {
 543                 if (strstr(p->pack_name, filename))
 544                         return add_pack(p);
 545                 p = p->next;
 546         }
 547         die("Filename %s not found in packed_git", filename);
 548 }
 549
 550 static void load_all(void)
 551 {
 552         struct packed_git *p = get_all_packs(the_repository);
 553
 554         while (p) {
 555                 add_pack(p);
 556                 p = p->next;
 557         }
 558 }
 559
 560 int cmd_pack_redundant(int argc, const char **argv, const char *prefix)
 561 {
 562         int i;
 563         int i_still_use_this = 0;
 564         struct pack_list *min = NULL, *red, *pl;
 565         struct llist *ignore;
 566         struct object_id *oid;
 567         char buf[GIT_MAX_HEXSZ + 2]; /* hex hash + \n + \0 */
 568
 569         if (argc == 2 && !strcmp(argv[1], "-h"))
 570                 usage(pack_redundant_usage);
 571
 572         for (i = 1; i < argc; i++) {
 573                 const char *arg = argv[i];
 574                 if (!strcmp(arg, "--")) {
 575                         i++;
 576                         break;
 577                 }
 578                 if (!strcmp(arg, "--all")) {
 579                         load_all_packs = 1;
 580                         continue;
 581                 }
 582                 if (!strcmp(arg, "--verbose")) {
 583                         verbose = 1;
 584                         continue;
 585                 }
 586                 if (!strcmp(arg, "--alt-odb")) {
 587                         alt_odb = 1;
 588                         continue;
 589                 }
 590                 if (!strcmp(arg, "--i-still-use-this")) {
 591                         i_still_use_this = 1;
 592                         continue;
 593                 }
 594                 if (*arg == '-')
 595                         usage(pack_redundant_usage);
 596                 else
 597                         break;
 598         }
 599
 600         if (!i_still_use_this) {
 601                 fputs(_("'git pack-redundant' is nominated for removal.\n"
 602                         "If you still use this command, please add an extra\n"
 603                         "option, '--i-still-use-this', on the command line\n"
 604                         "and let us know you still use it by sending an e-mail\n"
 605                         "to <git@vger.kernel.org>.  Thanks.\n"), stderr);
 606         }
 607
 608         if (load_all_packs)
 609                 load_all();
 610         else
 611                 while (*(argv + i) != NULL)
 612                         add_pack_file(*(argv + i++));
 613
 614         if (local_packs == NULL)
 615                 die("Zero packs found!");
 616
 617         load_all_objects();
 618
 619         if (alt_odb)
 620                 scan_alt_odb_packs();
 621
 622         /* ignore objects given on stdin */
 623         llist_init(&ignore);
 624         if (!isatty(0)) {
 625                 while (fgets(buf, sizeof(buf), stdin)) {
 626                         oid = xmalloc(sizeof(*oid));
 627                         if (get_oid_hex(buf, oid))
 628                                 die("Bad object ID on stdin: %s", buf);
 629                         llist_insert_sorted_unique(ignore, oid, NULL);
 630                 }
 631         }
 632         llist_sorted_difference_inplace(all_objects, ignore);
 633         pl = local_packs;
 634         while (pl) {
 635                 llist_sorted_difference_inplace(pl->remaining_objects, ignore);
 636                 pl = pl->next;
 637         }
 638
 639         cmp_local_packs();
 640
 641         minimize(&min);
 642
 643         if (verbose) {
 644                 fprintf(stderr, "There are %lu packs available in alt-odbs.\n",
 645                         (unsigned long)pack_list_size(altodb_packs));
 646                 fprintf(stderr, "The smallest (bytewise) set of packs is:\n");
 647                 pl = min;
 648                 while (pl) {
 649                         fprintf(stderr, "\t%s\n", pl->pack->pack_name);
 650                         pl = pl->next;
 651                 }
 652                 fprintf(stderr, "containing %lu duplicate objects "
 653                                 "with a total size of %lukb.\n",
 654                         (unsigned long)get_pack_redundancy(min),
 655                         (unsigned long)pack_set_bytecount(min)/1024);
 656                 fprintf(stderr, "A total of %lu unique objects were considered.\n",
 657                         (unsigned long)all_objects->size);
 658                 fprintf(stderr, "Redundant packs (with indexes):\n");
 659         }
 660         pl = red = pack_list_difference(local_packs, min);
 661         while (pl) {
 662                 printf("%s\n%s\n",
 663                        sha1_pack_index_name(pl->pack->hash),
 664                        pl->pack->pack_name);
 665                 pl = pl->next;
 666         }
 667         if (verbose)
 668                 fprintf(stderr, "%luMB of redundant packs in total.\n",
 669                         (unsigned long)pack_set_bytecount(red)/(1024*1024));
 670
 671         return 0;
 672 }