pack-bitmap-write.con commit Merge branch 'dl/credential-cache-socket-in-xdg-cache' into maint (cdc55aa)
   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.oid.hash,
  77                                                     NULL);
  78                        break;
  79                }
  80
  81                switch (real_type) {
  82                case OBJ_COMMIT:
  83                        ewah_set(writer.commits, i);
  84                        break;
  85
  86                case OBJ_TREE:
  87                        ewah_set(writer.trees, i);
  88                        break;
  89
  90                case OBJ_BLOB:
  91                        ewah_set(writer.blobs, i);
  92                        break;
  93
  94                case OBJ_TAG:
  95                        ewah_set(writer.tags, i);
  96                        break;
  97
  98                default:
  99                        die("Missing type information for %s (%d/%d)",
 100                            oid_to_hex(&entry->idx.oid), real_type,
 101                            entry->type);
 102                }
 103        }
 104}
 105
 106/**
 107 * Compute the actual bitmaps
 108 */
 109static struct object **seen_objects;
 110static unsigned int seen_objects_nr, seen_objects_alloc;
 111
 112static inline void push_bitmapped_commit(struct commit *commit, struct ewah_bitmap *reused)
 113{
 114        if (writer.selected_nr >= writer.selected_alloc) {
 115                writer.selected_alloc = (writer.selected_alloc + 32) * 2;
 116                REALLOC_ARRAY(writer.selected, writer.selected_alloc);
 117        }
 118
 119        writer.selected[writer.selected_nr].commit = commit;
 120        writer.selected[writer.selected_nr].bitmap = reused;
 121        writer.selected[writer.selected_nr].flags = 0;
 122
 123        writer.selected_nr++;
 124}
 125
 126static inline void mark_as_seen(struct object *object)
 127{
 128        ALLOC_GROW(seen_objects, seen_objects_nr + 1, seen_objects_alloc);
 129        seen_objects[seen_objects_nr++] = object;
 130}
 131
 132static inline void reset_all_seen(void)
 133{
 134        unsigned int i;
 135        for (i = 0; i < seen_objects_nr; ++i) {
 136                seen_objects[i]->flags &= ~(SEEN | ADDED | SHOWN);
 137        }
 138        seen_objects_nr = 0;
 139}
 140
 141static uint32_t find_object_pos(const unsigned char *sha1)
 142{
 143        struct object_entry *entry = packlist_find(writer.to_pack, sha1, NULL);
 144
 145        if (!entry) {
 146                die("Failed to write bitmap index. Packfile doesn't have full closure "
 147                        "(object %s is missing)", sha1_to_hex(sha1));
 148        }
 149
 150        return entry->in_pack_pos;
 151}
 152
 153static void show_object(struct object *object, const char *name, void *data)
 154{
 155        struct bitmap *base = data;
 156        bitmap_set(base, find_object_pos(object->oid.hash));
 157        mark_as_seen(object);
 158}
 159
 160static void show_commit(struct commit *commit, void *data)
 161{
 162        mark_as_seen((struct object *)commit);
 163}
 164
 165static int
 166add_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.oid.hash);
 170
 171        if (bitmap_get(base, bitmap_pos))
 172                return 0;
 173
 174        hash_pos = kh_get_sha1(writer.bitmaps, commit->object.oid.hash);
 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
 185static int
 186should_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
 207static 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
 247void 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->oid.hash, &hash_ret);
 313                if (hash_ret == 0)
 314                        die("Duplicate entry when writing index: %s",
 315                            oid_to_hex(&object->oid));
 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 */
 330static 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
 354static 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
 361void 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
 370static 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
 384void 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, 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.oid.hash);
 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.oid.hash);
 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]->oid.hash;
 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
 476                int commit_pos =
 477                        sha1_pos(stored->commit->object.oid.hash, 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
 490static 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
 503void bitmap_writer_set_checksum(unsigned char *sha1)
 504{
 505        hashcpy(writer.pack_checksum, sha1);
 506}
 507
 508void bitmap_writer_finish(struct pack_idx_entry **index,
 509                          uint32_t index_nr,
 510                          const char *filename,
 511                          uint16_t options)
 512{
 513        static uint16_t default_version = 1;
 514        static uint16_t flags = BITMAP_OPT_FULL_DAG;
 515        struct strbuf tmp_file = STRBUF_INIT;
 516        struct sha1file *f;
 517
 518        struct bitmap_disk_header header;
 519
 520        int fd = odb_mkstemp(&tmp_file, "pack/tmp_bitmap_XXXXXX");
 521
 522        f = sha1fd(fd, tmp_file.buf);
 523
 524        memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
 525        header.version = htons(default_version);
 526        header.options = htons(flags | options);
 527        header.entry_count = htonl(writer.selected_nr);
 528        hashcpy(header.checksum, writer.pack_checksum);
 529
 530        sha1write(f, &header, sizeof(header));
 531        dump_bitmap(f, writer.commits);
 532        dump_bitmap(f, writer.trees);
 533        dump_bitmap(f, writer.blobs);
 534        dump_bitmap(f, writer.tags);
 535        write_selected_commits_v1(f, index, index_nr);
 536
 537        if (options & BITMAP_OPT_HASH_CACHE)
 538                write_hash_cache(f, index, index_nr);
 539
 540        sha1close(f, NULL, CSUM_FSYNC);
 541
 542        if (adjust_shared_perm(tmp_file.buf))
 543                die_errno("unable to make temporary bitmap file readable");
 544
 545        if (rename(tmp_file.buf, filename))
 546                die_errno("unable to rename temporary bitmap file to '%s'", filename);
 547
 548        strbuf_release(&tmp_file);
 549}