pack-bitmap-write.con commit Merge branch 'jk/mbox-from-line' (26d0587)
   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
  14struct 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
  23struct 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
  41static struct bitmap_writer writer;
  42
  43void 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 */
  51void 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 */
 107static struct object **seen_objects;
 108static unsigned int seen_objects_nr, seen_objects_alloc;
 109
 110static 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
 124static 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
 130static 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
 139static 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
 151static 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
 159static void show_commit(struct commit *commit, void *data)
 160{
 161        mark_as_seen((struct object *)commit);
 162}
 163
 164static int
 165add_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
 184static int
 185should_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
 206static 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
 246void 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 */
 329static 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
 353static 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
 360void 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
 369static 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
 383void 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
 445static 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 */
 455static 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
 461static 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
 467static 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                struct bitmap_disk_entry on_disk;
 476
 477                int commit_pos =
 478                        sha1_pos(stored->commit->object.sha1, index, index_nr, sha1_access);
 479
 480                if (commit_pos < 0)
 481                        die("BUG: trying to write commit not in index");
 482
 483                on_disk.object_pos = htonl(commit_pos);
 484                on_disk.xor_offset = stored->xor_offset;
 485                on_disk.flags = stored->flags;
 486
 487                sha1write(f, &on_disk, sizeof(on_disk));
 488                dump_bitmap(f, stored->write_as);
 489        }
 490}
 491
 492static void write_hash_cache(struct sha1file *f,
 493                             struct pack_idx_entry **index,
 494                             uint32_t index_nr)
 495{
 496        uint32_t i;
 497
 498        for (i = 0; i < index_nr; ++i) {
 499                struct object_entry *entry = (struct object_entry *)index[i];
 500                uint32_t hash_value = htonl(entry->hash);
 501                sha1write(f, &hash_value, sizeof(hash_value));
 502        }
 503}
 504
 505void bitmap_writer_set_checksum(unsigned char *sha1)
 506{
 507        hashcpy(writer.pack_checksum, sha1);
 508}
 509
 510void bitmap_writer_finish(struct pack_idx_entry **index,
 511                          uint32_t index_nr,
 512                          const char *filename,
 513                          uint16_t options)
 514{
 515        static char tmp_file[PATH_MAX];
 516        static uint16_t default_version = 1;
 517        static uint16_t flags = BITMAP_OPT_FULL_DAG;
 518        struct sha1file *f;
 519
 520        struct bitmap_disk_header header;
 521
 522        int fd = odb_mkstemp(tmp_file, sizeof(tmp_file), "pack/tmp_bitmap_XXXXXX");
 523
 524        if (fd < 0)
 525                die_errno("unable to create '%s'", tmp_file);
 526        f = sha1fd(fd, tmp_file);
 527
 528        memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
 529        header.version = htons(default_version);
 530        header.options = htons(flags | options);
 531        header.entry_count = htonl(writer.selected_nr);
 532        hashcpy(header.checksum, writer.pack_checksum);
 533
 534        sha1write(f, &header, sizeof(header));
 535        dump_bitmap(f, writer.commits);
 536        dump_bitmap(f, writer.trees);
 537        dump_bitmap(f, writer.blobs);
 538        dump_bitmap(f, writer.tags);
 539        write_selected_commits_v1(f, index, index_nr);
 540
 541        if (options & BITMAP_OPT_HASH_CACHE)
 542                write_hash_cache(f, index, index_nr);
 543
 544        sha1close(f, NULL, CSUM_FSYNC);
 545
 546        if (adjust_shared_perm(tmp_file))
 547                die_errno("unable to make temporary bitmap file readable");
 548
 549        if (rename(tmp_file, filename))
 550                die_errno("unable to rename temporary bitmap file to '%s'", filename);
 551}