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                 writer.selected = xrealloc(writer.selected,
 115                                            writer.selected_alloc * sizeof(struct bitmapped_commit));
 116         }
 117
 118         writer.selected[writer.selected_nr].commit = commit;
 119         writer.selected[writer.selected_nr].bitmap = reused;
 120         writer.selected[writer.selected_nr].flags = 0;
 121
 122         writer.selected_nr++;
 123 }
 124
 125 static inline void mark_as_seen(struct object *object)
 126 {
 127         ALLOC_GROW(seen_objects, seen_objects_nr + 1, seen_objects_alloc);
 128         seen_objects[seen_objects_nr++] = object;
 129 }
 130
 131 static inline void reset_all_seen(void)
 132 {
 133         unsigned int i;
 134         for (i = 0; i < seen_objects_nr; ++i) {
 135                 seen_objects[i]->flags &= ~(SEEN | ADDED | SHOWN);
 136         }
 137         seen_objects_nr = 0;
 138 }
 139
 140 static uint32_t find_object_pos(const unsigned char *sha1)
 141 {
 142         struct object_entry *entry = packlist_find(writer.to_pack, sha1, NULL);
 143
 144         if (!entry) {
 145                 die("Failed to write bitmap index. Packfile doesn't have full closure "
 146                         "(object %s is missing)", sha1_to_hex(sha1));
 147         }
 148
 149         return entry->in_pack_pos;
 150 }
 151
 152 static void show_object(struct object *object, const struct name_path *path,
 153                         const char *last, void *data)
 154 {
 155         struct bitmap *base = data;
 156         bitmap_set(base, find_object_pos(object->sha1));
 157         mark_as_seen(object);
 158 }
 159
 160 static void show_commit(struct commit *commit, void *data)
 161 {
 162         mark_as_seen((struct object *)commit);
 163 }
 164
 165 static int
 166 add_to_include_set(struct bitmap *base, struct commit *commit)
 167 {
 168         khiter_t hash_pos;
 169         uint32_t bitmap_pos = find_object_pos(commit->object.sha1);
 170
 171         if (bitmap_get(base, bitmap_pos))
 172                 return 0;
 173
 174         hash_pos = kh_get_sha1(writer.bitmaps, commit->object.sha1);
 175         if (hash_pos < kh_end(writer.bitmaps)) {
 176                 struct bitmapped_commit *bc = kh_value(writer.bitmaps, hash_pos);
 177                 bitmap_or_ewah(base, bc->bitmap);
 178                 return 0;
 179         }
 180
 181         bitmap_set(base, bitmap_pos);
 182         return 1;
 183 }
 184
 185 static int
 186 should_include(struct commit *commit, void *_data)
 187 {
 188         struct bitmap *base = _data;
 189
 190         if (!add_to_include_set(base, commit)) {
 191                 struct commit_list *parent = commit->parents;
 192
 193                 mark_as_seen((struct object *)commit);
 194
 195                 while (parent) {
 196                         parent->item->object.flags |= SEEN;
 197                         mark_as_seen((struct object *)parent->item);
 198                         parent = parent->next;
 199                 }
 200
 201                 return 0;
 202         }
 203
 204         return 1;
 205 }
 206
 207 static void compute_xor_offsets(void)
 208 {
 209         static const int MAX_XOR_OFFSET_SEARCH = 10;
 210
 211         int i, next = 0;
 212
 213         while (next < writer.selected_nr) {
 214                 struct bitmapped_commit *stored = &writer.selected[next];
 215
 216                 int best_offset = 0;
 217                 struct ewah_bitmap *best_bitmap = stored->bitmap;
 218                 struct ewah_bitmap *test_xor;
 219
 220                 for (i = 1; i <= MAX_XOR_OFFSET_SEARCH; ++i) {
 221                         int curr = next - i;
 222
 223                         if (curr < 0)
 224                                 break;
 225
 226                         test_xor = ewah_pool_new();
 227                         ewah_xor(writer.selected[curr].bitmap, stored->bitmap, test_xor);
 228
 229                         if (test_xor->buffer_size < best_bitmap->buffer_size) {
 230                                 if (best_bitmap != stored->bitmap)
 231                                         ewah_pool_free(best_bitmap);
 232
 233                                 best_bitmap = test_xor;
 234                                 best_offset = i;
 235                         } else {
 236                                 ewah_pool_free(test_xor);
 237                         }
 238                 }
 239
 240                 stored->xor_offset = best_offset;
 241                 stored->write_as = best_bitmap;
 242
 243                 next++;
 244         }
 245 }
 246
 247 void bitmap_writer_build(struct packing_data *to_pack)
 248 {
 249         static const double REUSE_BITMAP_THRESHOLD = 0.2;
 250
 251         int i, reuse_after, need_reset;
 252         struct bitmap *base = bitmap_new();
 253         struct rev_info revs;
 254
 255         writer.bitmaps = kh_init_sha1();
 256         writer.to_pack = to_pack;
 257
 258         if (writer.show_progress)
 259                 writer.progress = start_progress("Building bitmaps", writer.selected_nr);
 260
 261         init_revisions(&revs, NULL);
 262         revs.tag_objects = 1;
 263         revs.tree_objects = 1;
 264         revs.blob_objects = 1;
 265         revs.no_walk = 0;
 266
 267         revs.include_check = should_include;
 268         reset_revision_walk();
 269
 270         reuse_after = writer.selected_nr * REUSE_BITMAP_THRESHOLD;
 271         need_reset = 0;
 272
 273         for (i = writer.selected_nr - 1; i >= 0; --i) {
 274                 struct bitmapped_commit *stored;
 275                 struct object *object;
 276
 277                 khiter_t hash_pos;
 278                 int hash_ret;
 279
 280                 stored = &writer.selected[i];
 281                 object = (struct object *)stored->commit;
 282
 283                 if (stored->bitmap == NULL) {
 284                         if (i < writer.selected_nr - 1 &&
 285                             (need_reset ||
 286                              !in_merge_bases(writer.selected[i + 1].commit,
 287                                              stored->commit))) {
 288                             bitmap_reset(base);
 289                             reset_all_seen();
 290                         }
 291
 292                         add_pending_object(&revs, object, "");
 293                         revs.include_check_data = base;
 294
 295                         if (prepare_revision_walk(&revs))
 296                                 die("revision walk setup failed");
 297
 298                         traverse_commit_list(&revs, show_commit, show_object, base);
 299
 300                         revs.pending.nr = 0;
 301                         revs.pending.alloc = 0;
 302                         revs.pending.objects = NULL;
 303
 304                         stored->bitmap = bitmap_to_ewah(base);
 305                         need_reset = 0;
 306                 } else
 307                         need_reset = 1;
 308
 309                 if (i >= reuse_after)
 310                         stored->flags |= BITMAP_FLAG_REUSE;
 311
 312                 hash_pos = kh_put_sha1(writer.bitmaps, object->sha1, &hash_ret);
 313                 if (hash_ret == 0)
 314                         die("Duplicate entry when writing index: %s",
 315                             sha1_to_hex(object->sha1));
 316
 317                 kh_value(writer.bitmaps, hash_pos) = stored;
 318                 display_progress(writer.progress, writer.selected_nr - i);
 319         }
 320
 321         bitmap_free(base);
 322         stop_progress(&writer.progress);
 323
 324         compute_xor_offsets();
 325 }
 326
 327 /**
 328  * Select the commits that will be bitmapped
 329  */
 330 static inline unsigned int next_commit_index(unsigned int idx)
 331 {
 332         static const unsigned int MIN_COMMITS = 100;
 333         static const unsigned int MAX_COMMITS = 5000;
 334
 335         static const unsigned int MUST_REGION = 100;
 336         static const unsigned int MIN_REGION = 20000;
 337
 338         unsigned int offset, next;
 339
 340         if (idx <= MUST_REGION)
 341                 return 0;
 342
 343         if (idx <= MIN_REGION) {
 344                 offset = idx - MUST_REGION;
 345                 return (offset < MIN_COMMITS) ? offset : MIN_COMMITS;
 346         }
 347
 348         offset = idx - MIN_REGION;
 349         next = (offset < MAX_COMMITS) ? offset : MAX_COMMITS;
 350
 351         return (next > MIN_COMMITS) ? next : MIN_COMMITS;
 352 }
 353
 354 static int date_compare(const void *_a, const void *_b)
 355 {
 356         struct commit *a = *(struct commit **)_a;
 357         struct commit *b = *(struct commit **)_b;
 358         return (long)b->date - (long)a->date;
 359 }
 360
 361 void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack)
 362 {
 363         if (prepare_bitmap_git() < 0)
 364                 return;
 365
 366         writer.reused = kh_init_sha1();
 367         rebuild_existing_bitmaps(to_pack, writer.reused, writer.show_progress);
 368 }
 369
 370 static struct ewah_bitmap *find_reused_bitmap(const unsigned char *sha1)
 371 {
 372         khiter_t hash_pos;
 373
 374         if (!writer.reused)
 375                 return NULL;
 376
 377         hash_pos = kh_get_sha1(writer.reused, sha1);
 378         if (hash_pos >= kh_end(writer.reused))
 379                 return NULL;
 380
 381         return kh_value(writer.reused, hash_pos);
 382 }
 383
 384 void bitmap_writer_select_commits(struct commit **indexed_commits,
 385                                   unsigned int indexed_commits_nr,
 386                                   int max_bitmaps)
 387 {
 388         unsigned int i = 0, j, next;
 389
 390         qsort(indexed_commits, indexed_commits_nr, sizeof(indexed_commits[0]),
 391               date_compare);
 392
 393         if (writer.show_progress)
 394                 writer.progress = start_progress("Selecting bitmap commits", 0);
 395
 396         if (indexed_commits_nr < 100) {
 397                 for (i = 0; i < indexed_commits_nr; ++i)
 398                         push_bitmapped_commit(indexed_commits[i], NULL);
 399                 return;
 400         }
 401
 402         for (;;) {
 403                 struct ewah_bitmap *reused_bitmap = NULL;
 404                 struct commit *chosen = NULL;
 405
 406                 next = next_commit_index(i);
 407
 408                 if (i + next >= indexed_commits_nr)
 409                         break;
 410
 411                 if (max_bitmaps > 0 && writer.selected_nr >= max_bitmaps) {
 412                         writer.selected_nr = max_bitmaps;
 413                         break;
 414                 }
 415
 416                 if (next == 0) {
 417                         chosen = indexed_commits[i];
 418                         reused_bitmap = find_reused_bitmap(chosen->object.sha1);
 419                 } else {
 420                         chosen = indexed_commits[i + next];
 421
 422                         for (j = 0; j <= next; ++j) {
 423                                 struct commit *cm = indexed_commits[i + j];
 424
 425                                 reused_bitmap = find_reused_bitmap(cm->object.sha1);
 426                                 if (reused_bitmap || (cm->object.flags & NEEDS_BITMAP) != 0) {
 427                                         chosen = cm;
 428                                         break;
 429                                 }
 430
 431                                 if (cm->parents && cm->parents->next)
 432                                         chosen = cm;
 433                         }
 434                 }
 435
 436                 push_bitmapped_commit(chosen, reused_bitmap);
 437
 438                 i += next + 1;
 439                 display_progress(writer.progress, i);
 440         }
 441
 442         stop_progress(&writer.progress);
 443 }
 444
 445
 446 static int sha1write_ewah_helper(void *f, const void *buf, size_t len)
 447 {
 448         /* sha1write will die on error */
 449         sha1write(f, buf, len);
 450         return len;
 451 }
 452
 453 /**
 454  * Write the bitmap index to disk
 455  */
 456 static inline void dump_bitmap(struct sha1file *f, struct ewah_bitmap *bitmap)
 457 {
 458         if (ewah_serialize_to(bitmap, sha1write_ewah_helper, f) < 0)
 459                 die("Failed to write bitmap index");
 460 }
 461
 462 static const unsigned char *sha1_access(size_t pos, void *table)
 463 {
 464         struct pack_idx_entry **index = table;
 465         return index[pos]->sha1;
 466 }
 467
 468 static void write_selected_commits_v1(struct sha1file *f,
 469                                       struct pack_idx_entry **index,
 470                                       uint32_t index_nr)
 471 {
 472         int i;
 473
 474         for (i = 0; i < writer.selected_nr; ++i) {
 475                 struct bitmapped_commit *stored = &writer.selected[i];
 476                 struct bitmap_disk_entry on_disk;
 477
 478                 int commit_pos =
 479                         sha1_pos(stored->commit->object.sha1, index, index_nr, sha1_access);
 480
 481                 if (commit_pos < 0)
 482                         die("BUG: trying to write commit not in index");
 483
 484                 on_disk.object_pos = htonl(commit_pos);
 485                 on_disk.xor_offset = stored->xor_offset;
 486                 on_disk.flags = stored->flags;
 487
 488                 sha1write(f, &on_disk, sizeof(on_disk));
 489                 dump_bitmap(f, stored->write_as);
 490         }
 491 }
 492
 493 static void write_hash_cache(struct sha1file *f,
 494                              struct pack_idx_entry **index,
 495                              uint32_t index_nr)
 496 {
 497         uint32_t i;
 498
 499         for (i = 0; i < index_nr; ++i) {
 500                 struct object_entry *entry = (struct object_entry *)index[i];
 501                 uint32_t hash_value = htonl(entry->hash);
 502                 sha1write(f, &hash_value, sizeof(hash_value));
 503         }
 504 }
 505
 506 void bitmap_writer_set_checksum(unsigned char *sha1)
 507 {
 508         hashcpy(writer.pack_checksum, sha1);
 509 }
 510
 511 void bitmap_writer_finish(struct pack_idx_entry **index,
 512                           uint32_t index_nr,
 513                           const char *filename,
 514                           uint16_t options)
 515 {
 516         static char tmp_file[PATH_MAX];
 517         static uint16_t default_version = 1;
 518         static uint16_t flags = BITMAP_OPT_FULL_DAG;
 519         struct sha1file *f;
 520
 521         struct bitmap_disk_header header;
 522
 523         int fd = odb_mkstemp(tmp_file, sizeof(tmp_file), "pack/tmp_bitmap_XXXXXX");
 524
 525         if (fd < 0)
 526                 die_errno("unable to create '%s'", tmp_file);
 527         f = sha1fd(fd, tmp_file);
 528
 529         memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
 530         header.version = htons(default_version);
 531         header.options = htons(flags | options);
 532         header.entry_count = htonl(writer.selected_nr);
 533         hashcpy(header.checksum, writer.pack_checksum);
 534
 535         sha1write(f, &header, sizeof(header));
 536         dump_bitmap(f, writer.commits);
 537         dump_bitmap(f, writer.trees);
 538         dump_bitmap(f, writer.blobs);
 539         dump_bitmap(f, writer.tags);
 540         write_selected_commits_v1(f, index, index_nr);
 541
 542         if (options & BITMAP_OPT_HASH_CACHE)
 543                 write_hash_cache(f, index, index_nr);
 544
 545         sha1close(f, NULL, CSUM_FSYNC);
 546
 547         if (adjust_shared_perm(tmp_file))
 548                 die_errno("unable to make temporary bitmap file readable");
 549
 550         if (rename(tmp_file, filename))
 551                 die_errno("unable to rename temporary bitmap file to '%s'", filename);
 552 }