pack-bitmap-write.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "tag.h"
   4 #include "diff.h"
   5 #include "revision.h"
   6 #include "list-objects.h"
   7 #include "progress.h"
   8 #include "pack-revindex.h"
   9 #include "pack.h"
  10 #include "pack-bitmap.h"
  11 #include "sha1-lookup.h"
  12 #include "pack-objects.h"
  13
  14 struct bitmapped_commit {
  15         struct commit *commit;
  16         struct ewah_bitmap *bitmap;
  17         struct ewah_bitmap *write_as;
  18         int flags;
  19         int xor_offset;
  20         uint32_t commit_pos;
  21 };
  22
  23 struct bitmap_writer {
  24         struct ewah_bitmap *commits;
  25         struct ewah_bitmap *trees;
  26         struct ewah_bitmap *blobs;
  27         struct ewah_bitmap *tags;
  28
  29         khash_sha1 *bitmaps;
  30         khash_sha1 *reused;
  31         struct packing_data *to_pack;
  32
  33         struct bitmapped_commit *selected;
  34         unsigned int selected_nr, selected_alloc;
  35
  36         struct progress *progress;
  37         int show_progress;
  38         unsigned char pack_checksum[20];
  39 };
  40
  41 static struct bitmap_writer writer;
  42
  43 void bitmap_writer_show_progress(int show)
  44 {
  45         writer.show_progress = show;
  46 }
  47
  48 /**
  49  * Build the initial type index for the packfile
  50  */
  51 void bitmap_writer_build_type_index(struct pack_idx_entry **index,
  52                                     uint32_t index_nr)
  53 {
  54         uint32_t i;
  55
  56         writer.commits = ewah_new();
  57         writer.trees = ewah_new();
  58         writer.blobs = ewah_new();
  59         writer.tags = ewah_new();
  60
  61         for (i = 0; i < index_nr; ++i) {
  62                 struct object_entry *entry = (struct object_entry *)index[i];
  63                 enum object_type real_type;
  64
  65                 entry->in_pack_pos = i;
  66
  67                 switch (entry->type) {
  68                 case OBJ_COMMIT:
  69                 case OBJ_TREE:
  70                 case OBJ_BLOB:
  71                 case OBJ_TAG:
  72                         real_type = entry->type;
  73                         break;
  74
  75                 default:
  76                         real_type = sha1_object_info(entry->idx.sha1, NULL);
  77                         break;
  78                 }
  79
  80                 switch (real_type) {
  81                 case OBJ_COMMIT:
  82                         ewah_set(writer.commits, i);
  83                         break;
  84
  85                 case OBJ_TREE:
  86                         ewah_set(writer.trees, i);
  87                         break;
  88
  89                 case OBJ_BLOB:
  90                         ewah_set(writer.blobs, i);
  91                         break;
  92
  93                 case OBJ_TAG:
  94                         ewah_set(writer.tags, i);
  95                         break;
  96
  97                 default:
  98                         die("Missing type information for %s (%d/%d)",
  99                             sha1_to_hex(entry->idx.sha1), real_type, entry->type);
 100                 }
 101         }
 102 }
 103
 104 /**
 105  * Compute the actual bitmaps
 106  */
 107 static struct object **seen_objects;
 108 static unsigned int seen_objects_nr, seen_objects_alloc;
 109
 110 static inline void push_bitmapped_commit(struct commit *commit, struct ewah_bitmap *reused)
 111 {
 112         if (writer.selected_nr >= writer.selected_alloc) {
 113                 writer.selected_alloc = (writer.selected_alloc + 32) * 2;
 114                 REALLOC_ARRAY(writer.selected, writer.selected_alloc);
 115         }
 116
 117         writer.selected[writer.selected_nr].commit = commit;
 118         writer.selected[writer.selected_nr].bitmap = reused;
 119         writer.selected[writer.selected_nr].flags = 0;
 120
 121         writer.selected_nr++;
 122 }
 123
 124 static inline void mark_as_seen(struct object *object)
 125 {
 126         ALLOC_GROW(seen_objects, seen_objects_nr + 1, seen_objects_alloc);
 127         seen_objects[seen_objects_nr++] = object;
 128 }
 129
 130 static inline void reset_all_seen(void)
 131 {
 132         unsigned int i;
 133         for (i = 0; i < seen_objects_nr; ++i) {
 134                 seen_objects[i]->flags &= ~(SEEN | ADDED | SHOWN);
 135         }
 136         seen_objects_nr = 0;
 137 }
 138
 139 static uint32_t find_object_pos(const unsigned char *sha1)
 140 {
 141         struct object_entry *entry = packlist_find(writer.to_pack, sha1, NULL);
 142
 143         if (!entry) {
 144                 die("Failed to write bitmap index. Packfile doesn't have full closure "
 145                         "(object %s is missing)", sha1_to_hex(sha1));
 146         }
 147
 148         return entry->in_pack_pos;
 149 }
 150
 151 static void show_object(struct object *object, const struct name_path *path,
 152                         const char *last, void *data)
 153 {
 154         struct bitmap *base = data;
 155         bitmap_set(base, find_object_pos(object->sha1));
 156         mark_as_seen(object);
 157 }
 158
 159 static void show_commit(struct commit *commit, void *data)
 160 {
 161         mark_as_seen((struct object *)commit);
 162 }
 163
 164 static int
 165 add_to_include_set(struct bitmap *base, struct commit *commit)
 166 {
 167         khiter_t hash_pos;
 168         uint32_t bitmap_pos = find_object_pos(commit->object.sha1);
 169
 170         if (bitmap_get(base, bitmap_pos))
 171                 return 0;
 172
 173         hash_pos = kh_get_sha1(writer.bitmaps, commit->object.sha1);
 174         if (hash_pos < kh_end(writer.bitmaps)) {
 175                 struct bitmapped_commit *bc = kh_value(writer.bitmaps, hash_pos);
 176                 bitmap_or_ewah(base, bc->bitmap);
 177                 return 0;
 178         }
 179
 180         bitmap_set(base, bitmap_pos);
 181         return 1;
 182 }
 183
 184 static int
 185 should_include(struct commit *commit, void *_data)
 186 {
 187         struct bitmap *base = _data;
 188
 189         if (!add_to_include_set(base, commit)) {
 190                 struct commit_list *parent = commit->parents;
 191
 192                 mark_as_seen((struct object *)commit);
 193
 194                 while (parent) {
 195                         parent->item->object.flags |= SEEN;
 196                         mark_as_seen((struct object *)parent->item);
 197                         parent = parent->next;
 198                 }
 199
 200                 return 0;
 201         }
 202
 203         return 1;
 204 }
 205
 206 static void compute_xor_offsets(void)
 207 {
 208         static const int MAX_XOR_OFFSET_SEARCH = 10;
 209
 210         int i, next = 0;
 211
 212         while (next < writer.selected_nr) {
 213                 struct bitmapped_commit *stored = &writer.selected[next];
 214
 215                 int best_offset = 0;
 216                 struct ewah_bitmap *best_bitmap = stored->bitmap;
 217                 struct ewah_bitmap *test_xor;
 218
 219                 for (i = 1; i <= MAX_XOR_OFFSET_SEARCH; ++i) {
 220                         int curr = next - i;
 221
 222                         if (curr < 0)
 223                                 break;
 224
 225                         test_xor = ewah_pool_new();
 226                         ewah_xor(writer.selected[curr].bitmap, stored->bitmap, test_xor);
 227
 228                         if (test_xor->buffer_size < best_bitmap->buffer_size) {
 229                                 if (best_bitmap != stored->bitmap)
 230                                         ewah_pool_free(best_bitmap);
 231
 232                                 best_bitmap = test_xor;
 233                                 best_offset = i;
 234                         } else {
 235                                 ewah_pool_free(test_xor);
 236                         }
 237                 }
 238
 239                 stored->xor_offset = best_offset;
 240                 stored->write_as = best_bitmap;
 241
 242                 next++;
 243         }
 244 }
 245
 246 void bitmap_writer_build(struct packing_data *to_pack)
 247 {
 248         static const double REUSE_BITMAP_THRESHOLD = 0.2;
 249
 250         int i, reuse_after, need_reset;
 251         struct bitmap *base = bitmap_new();
 252         struct rev_info revs;
 253
 254         writer.bitmaps = kh_init_sha1();
 255         writer.to_pack = to_pack;
 256
 257         if (writer.show_progress)
 258                 writer.progress = start_progress("Building bitmaps", writer.selected_nr);
 259
 260         init_revisions(&revs, NULL);
 261         revs.tag_objects = 1;
 262         revs.tree_objects = 1;
 263         revs.blob_objects = 1;
 264         revs.no_walk = 0;
 265
 266         revs.include_check = should_include;
 267         reset_revision_walk();
 268
 269         reuse_after = writer.selected_nr * REUSE_BITMAP_THRESHOLD;
 270         need_reset = 0;
 271
 272         for (i = writer.selected_nr - 1; i >= 0; --i) {
 273                 struct bitmapped_commit *stored;
 274                 struct object *object;
 275
 276                 khiter_t hash_pos;
 277                 int hash_ret;
 278
 279                 stored = &writer.selected[i];
 280                 object = (struct object *)stored->commit;
 281
 282                 if (stored->bitmap == NULL) {
 283                         if (i < writer.selected_nr - 1 &&
 284                             (need_reset ||
 285                              !in_merge_bases(writer.selected[i + 1].commit,
 286                                              stored->commit))) {
 287                             bitmap_reset(base);
 288                             reset_all_seen();
 289                         }
 290
 291                         add_pending_object(&revs, object, "");
 292                         revs.include_check_data = base;
 293
 294                         if (prepare_revision_walk(&revs))
 295                                 die("revision walk setup failed");
 296
 297                         traverse_commit_list(&revs, show_commit, show_object, base);
 298
 299                         revs.pending.nr = 0;
 300                         revs.pending.alloc = 0;
 301                         revs.pending.objects = NULL;
 302
 303                         stored->bitmap = bitmap_to_ewah(base);
 304                         need_reset = 0;
 305                 } else
 306                         need_reset = 1;
 307
 308                 if (i >= reuse_after)
 309                         stored->flags |= BITMAP_FLAG_REUSE;
 310
 311                 hash_pos = kh_put_sha1(writer.bitmaps, object->sha1, &hash_ret);
 312                 if (hash_ret == 0)
 313                         die("Duplicate entry when writing index: %s",
 314                             sha1_to_hex(object->sha1));
 315
 316                 kh_value(writer.bitmaps, hash_pos) = stored;
 317                 display_progress(writer.progress, writer.selected_nr - i);
 318         }
 319
 320         bitmap_free(base);
 321         stop_progress(&writer.progress);
 322
 323         compute_xor_offsets();
 324 }
 325
 326 /**
 327  * Select the commits that will be bitmapped
 328  */
 329 static inline unsigned int next_commit_index(unsigned int idx)
 330 {
 331         static const unsigned int MIN_COMMITS = 100;
 332         static const unsigned int MAX_COMMITS = 5000;
 333
 334         static const unsigned int MUST_REGION = 100;
 335         static const unsigned int MIN_REGION = 20000;
 336
 337         unsigned int offset, next;
 338
 339         if (idx <= MUST_REGION)
 340                 return 0;
 341
 342         if (idx <= MIN_REGION) {
 343                 offset = idx - MUST_REGION;
 344                 return (offset < MIN_COMMITS) ? offset : MIN_COMMITS;
 345         }
 346
 347         offset = idx - MIN_REGION;
 348         next = (offset < MAX_COMMITS) ? offset : MAX_COMMITS;
 349
 350         return (next > MIN_COMMITS) ? next : MIN_COMMITS;
 351 }
 352
 353 static int date_compare(const void *_a, const void *_b)
 354 {
 355         struct commit *a = *(struct commit **)_a;
 356         struct commit *b = *(struct commit **)_b;
 357         return (long)b->date - (long)a->date;
 358 }
 359
 360 void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack)
 361 {
 362         if (prepare_bitmap_git() < 0)
 363                 return;
 364
 365         writer.reused = kh_init_sha1();
 366         rebuild_existing_bitmaps(to_pack, writer.reused, writer.show_progress);
 367 }
 368
 369 static struct ewah_bitmap *find_reused_bitmap(const unsigned char *sha1)
 370 {
 371         khiter_t hash_pos;
 372
 373         if (!writer.reused)
 374                 return NULL;
 375
 376         hash_pos = kh_get_sha1(writer.reused, sha1);
 377         if (hash_pos >= kh_end(writer.reused))
 378                 return NULL;
 379
 380         return kh_value(writer.reused, hash_pos);
 381 }
 382
 383 void bitmap_writer_select_commits(struct commit **indexed_commits,
 384                                   unsigned int indexed_commits_nr,
 385                                   int max_bitmaps)
 386 {
 387         unsigned int i = 0, j, next;
 388
 389         qsort(indexed_commits, indexed_commits_nr, sizeof(indexed_commits[0]),
 390               date_compare);
 391
 392         if (writer.show_progress)
 393                 writer.progress = start_progress("Selecting bitmap commits", 0);
 394
 395         if (indexed_commits_nr < 100) {
 396                 for (i = 0; i < indexed_commits_nr; ++i)
 397                         push_bitmapped_commit(indexed_commits[i], NULL);
 398                 return;
 399         }
 400
 401         for (;;) {
 402                 struct ewah_bitmap *reused_bitmap = NULL;
 403                 struct commit *chosen = NULL;
 404
 405                 next = next_commit_index(i);
 406
 407                 if (i + next >= indexed_commits_nr)
 408                         break;
 409
 410                 if (max_bitmaps > 0 && writer.selected_nr >= max_bitmaps) {
 411                         writer.selected_nr = max_bitmaps;
 412                         break;
 413                 }
 414
 415                 if (next == 0) {
 416                         chosen = indexed_commits[i];
 417                         reused_bitmap = find_reused_bitmap(chosen->object.sha1);
 418                 } else {
 419                         chosen = indexed_commits[i + next];
 420
 421                         for (j = 0; j <= next; ++j) {
 422                                 struct commit *cm = indexed_commits[i + j];
 423
 424                                 reused_bitmap = find_reused_bitmap(cm->object.sha1);
 425                                 if (reused_bitmap || (cm->object.flags & NEEDS_BITMAP) != 0) {
 426                                         chosen = cm;
 427                                         break;
 428                                 }
 429
 430                                 if (cm->parents && cm->parents->next)
 431                                         chosen = cm;
 432                         }
 433                 }
 434
 435                 push_bitmapped_commit(chosen, reused_bitmap);
 436
 437                 i += next + 1;
 438                 display_progress(writer.progress, i);
 439         }
 440
 441         stop_progress(&writer.progress);
 442 }
 443
 444
 445 static int sha1write_ewah_helper(void *f, const void *buf, size_t len)
 446 {
 447         /* sha1write will die on error */
 448         sha1write(f, buf, len);
 449         return len;
 450 }
 451
 452 /**
 453  * Write the bitmap index to disk
 454  */
 455 static inline void dump_bitmap(struct sha1file *f, struct ewah_bitmap *bitmap)
 456 {
 457         if (ewah_serialize_to(bitmap, sha1write_ewah_helper, f) < 0)
 458                 die("Failed to write bitmap index");
 459 }
 460
 461 static const unsigned char *sha1_access(size_t pos, void *table)
 462 {
 463         struct pack_idx_entry **index = table;
 464         return index[pos]->sha1;
 465 }
 466
 467 static void write_selected_commits_v1(struct sha1file *f,
 468                                       struct pack_idx_entry **index,
 469                                       uint32_t index_nr)
 470 {
 471         int i;
 472
 473         for (i = 0; i < writer.selected_nr; ++i) {
 474                 struct bitmapped_commit *stored = &writer.selected[i];
 475
 476                 int commit_pos =
 477                         sha1_pos(stored->commit->object.sha1, index, index_nr, sha1_access);
 478
 479                 if (commit_pos < 0)
 480                         die("BUG: trying to write commit not in index");
 481
 482                 sha1write_be32(f, commit_pos);
 483                 sha1write_u8(f, stored->xor_offset);
 484                 sha1write_u8(f, stored->flags);
 485
 486                 dump_bitmap(f, stored->write_as);
 487         }
 488 }
 489
 490 static void write_hash_cache(struct sha1file *f,
 491                              struct pack_idx_entry **index,
 492                              uint32_t index_nr)
 493 {
 494         uint32_t i;
 495
 496         for (i = 0; i < index_nr; ++i) {
 497                 struct object_entry *entry = (struct object_entry *)index[i];
 498                 uint32_t hash_value = htonl(entry->hash);
 499                 sha1write(f, &hash_value, sizeof(hash_value));
 500         }
 501 }
 502
 503 void bitmap_writer_set_checksum(unsigned char *sha1)
 504 {
 505         hashcpy(writer.pack_checksum, sha1);
 506 }
 507
 508 void bitmap_writer_finish(struct pack_idx_entry **index,
 509                           uint32_t index_nr,
 510                           const char *filename,
 511                           uint16_t options)
 512 {
 513         static char tmp_file[PATH_MAX];
 514         static uint16_t default_version = 1;
 515         static uint16_t flags = BITMAP_OPT_FULL_DAG;
 516         struct sha1file *f;
 517
 518         struct bitmap_disk_header header;
 519
 520         int fd = odb_mkstemp(tmp_file, sizeof(tmp_file), "pack/tmp_bitmap_XXXXXX");
 521
 522         if (fd < 0)
 523                 die_errno("unable to create '%s'", tmp_file);
 524         f = sha1fd(fd, tmp_file);
 525
 526         memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
 527         header.version = htons(default_version);
 528         header.options = htons(flags | options);
 529         header.entry_count = htonl(writer.selected_nr);
 530         hashcpy(header.checksum, writer.pack_checksum);
 531
 532         sha1write(f, &header, sizeof(header));
 533         dump_bitmap(f, writer.commits);
 534         dump_bitmap(f, writer.trees);
 535         dump_bitmap(f, writer.blobs);
 536         dump_bitmap(f, writer.tags);
 537         write_selected_commits_v1(f, index, index_nr);
 538
 539         if (options & BITMAP_OPT_HASH_CACHE)
 540                 write_hash_cache(f, index, index_nr);
 541
 542         sha1close(f, NULL, CSUM_FSYNC);
 543
 544         if (adjust_shared_perm(tmp_file))
 545                 die_errno("unable to make temporary bitmap file readable");
 546
 547         if (rename(tmp_file, filename))
 548                 die_errno("unable to rename temporary bitmap file to '%s'", filename);
 549 }