git.oblomov.eu Git - git/blob - commit-graph.c

   1 #include "git-compat-util.h"
   2 #include "config.h"
   3 #include "lockfile.h"
   4 #include "pack.h"
   5 #include "packfile.h"
   6 #include "commit.h"
   7 #include "object.h"
   8 #include "refs.h"
   9 #include "revision.h"
  10 #include "sha1-lookup.h"
  11 #include "commit-graph.h"
  12 #include "object-store.h"
  13 #include "alloc.h"
  14 #include "hashmap.h"
  15 #include "replace-object.h"
  16 #include "progress.h"
  17 #include "bloom.h"
  18 #include "commit-slab.h"
  19 #include "shallow.h"
  20 #include "json-writer.h"
  21 #include "trace2.h"
  22
  23 void git_test_write_commit_graph_or_die(void)
  24 {
  25         int flags = 0;
  26         if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0))
  27                 return;
  28
  29         if (git_env_bool(GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS, 0))
  30                 flags = COMMIT_GRAPH_WRITE_BLOOM_FILTERS;
  31
  32         if (write_commit_graph_reachable(the_repository->objects->odb,
  33                                          flags, NULL))
  34                 die("failed to write commit-graph under GIT_TEST_COMMIT_GRAPH");
  35 }
  36
  37 #define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */
  38 #define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
  39 #define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
  40 #define GRAPH_CHUNKID_DATA 0x43444154 /* "CDAT" */
  41 #define GRAPH_CHUNKID_GENERATION_DATA 0x47444154 /* "GDAT" */
  42 #define GRAPH_CHUNKID_GENERATION_DATA_OVERFLOW 0x47444f56 /* "GDOV" */
  43 #define GRAPH_CHUNKID_EXTRAEDGES 0x45444745 /* "EDGE" */
  44 #define GRAPH_CHUNKID_BLOOMINDEXES 0x42494458 /* "BIDX" */
  45 #define GRAPH_CHUNKID_BLOOMDATA 0x42444154 /* "BDAT" */
  46 #define GRAPH_CHUNKID_BASE 0x42415345 /* "BASE" */
  47 #define MAX_NUM_CHUNKS 9
  48
  49 #define GRAPH_DATA_WIDTH (the_hash_algo->rawsz + 16)
  50
  51 #define GRAPH_VERSION_1 0x1
  52 #define GRAPH_VERSION GRAPH_VERSION_1
  53
  54 #define GRAPH_EXTRA_EDGES_NEEDED 0x80000000
  55 #define GRAPH_EDGE_LAST_MASK 0x7fffffff
  56 #define GRAPH_PARENT_NONE 0x70000000
  57
  58 #define GRAPH_LAST_EDGE 0x80000000
  59
  60 #define GRAPH_HEADER_SIZE 8
  61 #define GRAPH_FANOUT_SIZE (4 * 256)
  62 #define GRAPH_CHUNKLOOKUP_WIDTH 12
  63 #define GRAPH_MIN_SIZE (GRAPH_HEADER_SIZE + 4 * GRAPH_CHUNKLOOKUP_WIDTH \
  64                         + GRAPH_FANOUT_SIZE + the_hash_algo->rawsz)
  65
  66 #define CORRECTED_COMMIT_DATE_OFFSET_OVERFLOW (1ULL << 31)
  67
  68 /* Remember to update object flag allocation in object.h */
  69 #define REACHABLE       (1u<<15)
  70
  71 define_commit_slab(topo_level_slab, uint32_t);
  72
  73 /* Keep track of the order in which commits are added to our list. */
  74 define_commit_slab(commit_pos, int);
  75 static struct commit_pos commit_pos = COMMIT_SLAB_INIT(1, commit_pos);
  76
  77 static void set_commit_pos(struct repository *r, const struct object_id *oid)
  78 {
  79         static int32_t max_pos;
  80         struct commit *commit = lookup_commit(r, oid);
  81
  82         if (!commit)
  83                 return; /* should never happen, but be lenient */
  84
  85         *commit_pos_at(&commit_pos, commit) = max_pos++;
  86 }
  87
  88 static int commit_pos_cmp(const void *va, const void *vb)
  89 {
  90         const struct commit *a = *(const struct commit **)va;
  91         const struct commit *b = *(const struct commit **)vb;
  92         return commit_pos_at(&commit_pos, a) -
  93                commit_pos_at(&commit_pos, b);
  94 }
  95
  96 define_commit_slab(commit_graph_data_slab, struct commit_graph_data);
  97 static struct commit_graph_data_slab commit_graph_data_slab =
  98         COMMIT_SLAB_INIT(1, commit_graph_data_slab);
  99
 100 uint32_t commit_graph_position(const struct commit *c)
 101 {
 102         struct commit_graph_data *data =
 103                 commit_graph_data_slab_peek(&commit_graph_data_slab, c);
 104
 105         return data ? data->graph_pos : COMMIT_NOT_FROM_GRAPH;
 106 }
 107
 108 timestamp_t commit_graph_generation(const struct commit *c)
 109 {
 110         struct commit_graph_data *data =
 111                 commit_graph_data_slab_peek(&commit_graph_data_slab, c);
 112
 113         if (!data)
 114                 return GENERATION_NUMBER_INFINITY;
 115         else if (data->graph_pos == COMMIT_NOT_FROM_GRAPH)
 116                 return GENERATION_NUMBER_INFINITY;
 117
 118         return data->generation;
 119 }
 120
 121 static struct commit_graph_data *commit_graph_data_at(const struct commit *c)
 122 {
 123         unsigned int i, nth_slab;
 124         struct commit_graph_data *data =
 125                 commit_graph_data_slab_peek(&commit_graph_data_slab, c);
 126
 127         if (data)
 128                 return data;
 129
 130         nth_slab = c->index / commit_graph_data_slab.slab_size;
 131         data = commit_graph_data_slab_at(&commit_graph_data_slab, c);
 132
 133         /*
 134          * commit-slab initializes elements with zero, overwrite this with
 135          * COMMIT_NOT_FROM_GRAPH for graph_pos.
 136          *
 137          * We avoid initializing generation with checking if graph position
 138          * is not COMMIT_NOT_FROM_GRAPH.
 139          */
 140         for (i = 0; i < commit_graph_data_slab.slab_size; i++) {
 141                 commit_graph_data_slab.slab[nth_slab][i].graph_pos =
 142                         COMMIT_NOT_FROM_GRAPH;
 143         }
 144
 145         return data;
 146 }
 147
 148 /*
 149  * Should be used only while writing commit-graph as it compares
 150  * generation value of commits by directly accessing commit-slab.
 151  */
 152 static int commit_gen_cmp(const void *va, const void *vb)
 153 {
 154         const struct commit *a = *(const struct commit **)va;
 155         const struct commit *b = *(const struct commit **)vb;
 156
 157         const timestamp_t generation_a = commit_graph_data_at(a)->generation;
 158         const timestamp_t generation_b = commit_graph_data_at(b)->generation;
 159         /* lower generation commits first */
 160         if (generation_a < generation_b)
 161                 return -1;
 162         else if (generation_a > generation_b)
 163                 return 1;
 164
 165         /* use date as a heuristic when generations are equal */
 166         if (a->date < b->date)
 167                 return -1;
 168         else if (a->date > b->date)
 169                 return 1;
 170         return 0;
 171 }
 172
 173 char *get_commit_graph_filename(struct object_directory *obj_dir)
 174 {
 175         return xstrfmt("%s/info/commit-graph", obj_dir->path);
 176 }
 177
 178 static char *get_split_graph_filename(struct object_directory *odb,
 179                                       const char *oid_hex)
 180 {
 181         return xstrfmt("%s/info/commit-graphs/graph-%s.graph", odb->path,
 182                        oid_hex);
 183 }
 184
 185 char *get_commit_graph_chain_filename(struct object_directory *odb)
 186 {
 187         return xstrfmt("%s/info/commit-graphs/commit-graph-chain", odb->path);
 188 }
 189
 190 static uint8_t oid_version(void)
 191 {
 192         switch (hash_algo_by_ptr(the_hash_algo)) {
 193         case GIT_HASH_SHA1:
 194                 return 1;
 195         case GIT_HASH_SHA256:
 196                 return 2;
 197         default:
 198                 die(_("invalid hash version"));
 199         }
 200 }
 201
 202 static struct commit_graph *alloc_commit_graph(void)
 203 {
 204         struct commit_graph *g = xcalloc(1, sizeof(*g));
 205
 206         return g;
 207 }
 208
 209 extern int read_replace_refs;
 210
 211 static int commit_graph_compatible(struct repository *r)
 212 {
 213         if (!r->gitdir)
 214                 return 0;
 215
 216         if (read_replace_refs) {
 217                 prepare_replace_object(r);
 218                 if (hashmap_get_size(&r->objects->replace_map->map))
 219                         return 0;
 220         }
 221
 222         prepare_commit_graft(r);
 223         if (r->parsed_objects &&
 224             (r->parsed_objects->grafts_nr || r->parsed_objects->substituted_parent))
 225                 return 0;
 226         if (is_repository_shallow(r))
 227                 return 0;
 228
 229         return 1;
 230 }
 231
 232 int open_commit_graph(const char *graph_file, int *fd, struct stat *st)
 233 {
 234         *fd = git_open(graph_file);
 235         if (*fd < 0)
 236                 return 0;
 237         if (fstat(*fd, st)) {
 238                 close(*fd);
 239                 return 0;
 240         }
 241         return 1;
 242 }
 243
 244 struct commit_graph *load_commit_graph_one_fd_st(struct repository *r,
 245                                                  int fd, struct stat *st,
 246                                                  struct object_directory *odb)
 247 {
 248         void *graph_map;
 249         size_t graph_size;
 250         struct commit_graph *ret;
 251
 252         graph_size = xsize_t(st->st_size);
 253
 254         if (graph_size < GRAPH_MIN_SIZE) {
 255                 close(fd);
 256                 error(_("commit-graph file is too small"));
 257                 return NULL;
 258         }
 259         graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
 260         close(fd);
 261         ret = parse_commit_graph(r, graph_map, graph_size);
 262
 263         if (ret)
 264                 ret->odb = odb;
 265         else
 266                 munmap(graph_map, graph_size);
 267
 268         return ret;
 269 }
 270
 271 static int verify_commit_graph_lite(struct commit_graph *g)
 272 {
 273         /*
 274          * Basic validation shared between parse_commit_graph()
 275          * which'll be called every time the graph is used, and the
 276          * much more expensive verify_commit_graph() used by
 277          * "commit-graph verify".
 278          *
 279          * There should only be very basic checks here to ensure that
 280          * we don't e.g. segfault in fill_commit_in_graph(), but
 281          * because this is a very hot codepath nothing that e.g. loops
 282          * over g->num_commits, or runs a checksum on the commit-graph
 283          * itself.
 284          */
 285         if (!g->chunk_oid_fanout) {
 286                 error("commit-graph is missing the OID Fanout chunk");
 287                 return 1;
 288         }
 289         if (!g->chunk_oid_lookup) {
 290                 error("commit-graph is missing the OID Lookup chunk");
 291                 return 1;
 292         }
 293         if (!g->chunk_commit_data) {
 294                 error("commit-graph is missing the Commit Data chunk");
 295                 return 1;
 296         }
 297
 298         return 0;
 299 }
 300
 301 struct commit_graph *parse_commit_graph(struct repository *r,
 302                                         void *graph_map, size_t graph_size)
 303 {
 304         const unsigned char *data, *chunk_lookup;
 305         uint32_t i;
 306         struct commit_graph *graph;
 307         uint64_t next_chunk_offset;
 308         uint32_t graph_signature;
 309         unsigned char graph_version, hash_version;
 310
 311         if (!graph_map)
 312                 return NULL;
 313
 314         if (graph_size < GRAPH_MIN_SIZE)
 315                 return NULL;
 316
 317         data = (const unsigned char *)graph_map;
 318
 319         graph_signature = get_be32(data);
 320         if (graph_signature != GRAPH_SIGNATURE) {
 321                 error(_("commit-graph signature %X does not match signature %X"),
 322                       graph_signature, GRAPH_SIGNATURE);
 323                 return NULL;
 324         }
 325
 326         graph_version = *(unsigned char*)(data + 4);
 327         if (graph_version != GRAPH_VERSION) {
 328                 error(_("commit-graph version %X does not match version %X"),
 329                       graph_version, GRAPH_VERSION);
 330                 return NULL;
 331         }
 332
 333         hash_version = *(unsigned char*)(data + 5);
 334         if (hash_version != oid_version()) {
 335                 error(_("commit-graph hash version %X does not match version %X"),
 336                       hash_version, oid_version());
 337                 return NULL;
 338         }
 339
 340         prepare_repo_settings(r);
 341
 342         graph = alloc_commit_graph();
 343
 344         graph->hash_len = the_hash_algo->rawsz;
 345         graph->num_chunks = *(unsigned char*)(data + 6);
 346         graph->data = graph_map;
 347         graph->data_len = graph_size;
 348
 349         if (graph_size < GRAPH_HEADER_SIZE +
 350                          (graph->num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH +
 351                          GRAPH_FANOUT_SIZE + the_hash_algo->rawsz) {
 352                 error(_("commit-graph file is too small to hold %u chunks"),
 353                       graph->num_chunks);
 354                 free(graph);
 355                 return NULL;
 356         }
 357
 358         chunk_lookup = data + 8;
 359         next_chunk_offset = get_be64(chunk_lookup + 4);
 360         for (i = 0; i < graph->num_chunks; i++) {
 361                 uint32_t chunk_id;
 362                 uint64_t chunk_offset = next_chunk_offset;
 363                 int chunk_repeated = 0;
 364
 365                 chunk_id = get_be32(chunk_lookup + 0);
 366
 367                 chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
 368                 next_chunk_offset = get_be64(chunk_lookup + 4);
 369
 370                 if (chunk_offset > graph_size - the_hash_algo->rawsz) {
 371                         error(_("commit-graph improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
 372                               (uint32_t)chunk_offset);
 373                         goto free_and_return;
 374                 }
 375
 376                 switch (chunk_id) {
 377                 case GRAPH_CHUNKID_OIDFANOUT:
 378                         if (graph->chunk_oid_fanout)
 379                                 chunk_repeated = 1;
 380                         else
 381                                 graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
 382                         break;
 383
 384                 case GRAPH_CHUNKID_OIDLOOKUP:
 385                         if (graph->chunk_oid_lookup)
 386                                 chunk_repeated = 1;
 387                         else {
 388                                 graph->chunk_oid_lookup = data + chunk_offset;
 389                                 graph->num_commits = (next_chunk_offset - chunk_offset)
 390                                                      / graph->hash_len;
 391                         }
 392                         break;
 393
 394                 case GRAPH_CHUNKID_DATA:
 395                         if (graph->chunk_commit_data)
 396                                 chunk_repeated = 1;
 397                         else
 398                                 graph->chunk_commit_data = data + chunk_offset;
 399                         break;
 400
 401                 case GRAPH_CHUNKID_GENERATION_DATA:
 402                         if (graph->chunk_generation_data)
 403                                 chunk_repeated = 1;
 404                         else
 405                                 graph->chunk_generation_data = data + chunk_offset;
 406                         break;
 407
 408                 case GRAPH_CHUNKID_GENERATION_DATA_OVERFLOW:
 409                         if (graph->chunk_generation_data_overflow)
 410                                 chunk_repeated = 1;
 411                         else
 412                                 graph->chunk_generation_data_overflow = data + chunk_offset;
 413                         break;
 414
 415                 case GRAPH_CHUNKID_EXTRAEDGES:
 416                         if (graph->chunk_extra_edges)
 417                                 chunk_repeated = 1;
 418                         else
 419                                 graph->chunk_extra_edges = data + chunk_offset;
 420                         break;
 421
 422                 case GRAPH_CHUNKID_BASE:
 423                         if (graph->chunk_base_graphs)
 424                                 chunk_repeated = 1;
 425                         else
 426                                 graph->chunk_base_graphs = data + chunk_offset;
 427                         break;
 428
 429                 case GRAPH_CHUNKID_BLOOMINDEXES:
 430                         if (graph->chunk_bloom_indexes)
 431                                 chunk_repeated = 1;
 432                         else if (r->settings.commit_graph_read_changed_paths)
 433                                 graph->chunk_bloom_indexes = data + chunk_offset;
 434                         break;
 435
 436                 case GRAPH_CHUNKID_BLOOMDATA:
 437                         if (graph->chunk_bloom_data)
 438                                 chunk_repeated = 1;
 439                         else if (r->settings.commit_graph_read_changed_paths) {
 440                                 uint32_t hash_version;
 441                                 graph->chunk_bloom_data = data + chunk_offset;
 442                                 hash_version = get_be32(data + chunk_offset);
 443
 444                                 if (hash_version != 1)
 445                                         break;
 446
 447                                 graph->bloom_filter_settings = xmalloc(sizeof(struct bloom_filter_settings));
 448                                 graph->bloom_filter_settings->hash_version = hash_version;
 449                                 graph->bloom_filter_settings->num_hashes = get_be32(data + chunk_offset + 4);
 450                                 graph->bloom_filter_settings->bits_per_entry = get_be32(data + chunk_offset + 8);
 451                                 graph->bloom_filter_settings->max_changed_paths = DEFAULT_BLOOM_MAX_CHANGES;
 452                         }
 453                         break;
 454                 }
 455
 456                 if (chunk_repeated) {
 457                         error(_("commit-graph chunk id %08x appears multiple times"), chunk_id);
 458                         goto free_and_return;
 459                 }
 460         }
 461
 462         if (graph->chunk_bloom_indexes && graph->chunk_bloom_data) {
 463                 init_bloom_filters();
 464         } else {
 465                 /* We need both the bloom chunks to exist together. Else ignore the data */
 466                 graph->chunk_bloom_indexes = NULL;
 467                 graph->chunk_bloom_data = NULL;
 468                 FREE_AND_NULL(graph->bloom_filter_settings);
 469         }
 470
 471         hashcpy(graph->oid.hash, graph->data + graph->data_len - graph->hash_len);
 472
 473         if (verify_commit_graph_lite(graph))
 474                 goto free_and_return;
 475
 476         return graph;
 477
 478 free_and_return:
 479         free(graph->bloom_filter_settings);
 480         free(graph);
 481         return NULL;
 482 }
 483
 484 static struct commit_graph *load_commit_graph_one(struct repository *r,
 485                                                   const char *graph_file,
 486                                                   struct object_directory *odb)
 487 {
 488
 489         struct stat st;
 490         int fd;
 491         struct commit_graph *g;
 492         int open_ok = open_commit_graph(graph_file, &fd, &st);
 493
 494         if (!open_ok)
 495                 return NULL;
 496
 497         g = load_commit_graph_one_fd_st(r, fd, &st, odb);
 498
 499         if (g)
 500                 g->filename = xstrdup(graph_file);
 501
 502         return g;
 503 }
 504
 505 static struct commit_graph *load_commit_graph_v1(struct repository *r,
 506                                                  struct object_directory *odb)
 507 {
 508         char *graph_name = get_commit_graph_filename(odb);
 509         struct commit_graph *g = load_commit_graph_one(r, graph_name, odb);
 510         free(graph_name);
 511
 512         return g;
 513 }
 514
 515 static int add_graph_to_chain(struct commit_graph *g,
 516                               struct commit_graph *chain,
 517                               struct object_id *oids,
 518                               int n)
 519 {
 520         struct commit_graph *cur_g = chain;
 521
 522         if (n && !g->chunk_base_graphs) {
 523                 warning(_("commit-graph has no base graphs chunk"));
 524                 return 0;
 525         }
 526
 527         while (n) {
 528                 n--;
 529
 530                 if (!cur_g ||
 531                     !oideq(&oids[n], &cur_g->oid) ||
 532                     !hasheq(oids[n].hash, g->chunk_base_graphs + g->hash_len * n)) {
 533                         warning(_("commit-graph chain does not match"));
 534                         return 0;
 535                 }
 536
 537                 cur_g = cur_g->base_graph;
 538         }
 539
 540         g->base_graph = chain;
 541
 542         if (chain)
 543                 g->num_commits_in_base = chain->num_commits + chain->num_commits_in_base;
 544
 545         return 1;
 546 }
 547
 548 static struct commit_graph *load_commit_graph_chain(struct repository *r,
 549                                                     struct object_directory *odb)
 550 {
 551         struct commit_graph *graph_chain = NULL;
 552         struct strbuf line = STRBUF_INIT;
 553         struct stat st;
 554         struct object_id *oids;
 555         int i = 0, valid = 1, count;
 556         char *chain_name = get_commit_graph_chain_filename(odb);
 557         FILE *fp;
 558         int stat_res;
 559
 560         fp = fopen(chain_name, "r");
 561         stat_res = stat(chain_name, &st);
 562         free(chain_name);
 563
 564         if (!fp ||
 565             stat_res ||
 566             st.st_size <= the_hash_algo->hexsz)
 567                 return NULL;
 568
 569         count = st.st_size / (the_hash_algo->hexsz + 1);
 570         oids = xcalloc(count, sizeof(struct object_id));
 571
 572         prepare_alt_odb(r);
 573
 574         for (i = 0; i < count; i++) {
 575                 struct object_directory *odb;
 576
 577                 if (strbuf_getline_lf(&line, fp) == EOF)
 578                         break;
 579
 580                 if (get_oid_hex(line.buf, &oids[i])) {
 581                         warning(_("invalid commit-graph chain: line '%s' not a hash"),
 582                                 line.buf);
 583                         valid = 0;
 584                         break;
 585                 }
 586
 587                 valid = 0;
 588                 for (odb = r->objects->odb; odb; odb = odb->next) {
 589                         char *graph_name = get_split_graph_filename(odb, line.buf);
 590                         struct commit_graph *g = load_commit_graph_one(r, graph_name, odb);
 591
 592                         free(graph_name);
 593
 594                         if (g) {
 595                                 if (add_graph_to_chain(g, graph_chain, oids, i)) {
 596                                         graph_chain = g;
 597                                         valid = 1;
 598                                 }
 599
 600                                 break;
 601                         }
 602                 }
 603
 604                 if (!valid) {
 605                         warning(_("unable to find all commit-graph files"));
 606                         break;
 607                 }
 608         }
 609
 610         free(oids);
 611         fclose(fp);
 612         strbuf_release(&line);
 613
 614         return graph_chain;
 615 }
 616
 617 static void validate_mixed_generation_chain(struct commit_graph *g)
 618 {
 619         int read_generation_data;
 620
 621         if (!g)
 622                 return;
 623
 624         read_generation_data = !!g->chunk_generation_data;
 625
 626         while (g) {
 627                 g->read_generation_data = read_generation_data;
 628                 g = g->base_graph;
 629         }
 630 }
 631
 632 struct commit_graph *read_commit_graph_one(struct repository *r,
 633                                            struct object_directory *odb)
 634 {
 635         struct commit_graph *g = load_commit_graph_v1(r, odb);
 636
 637         if (!g)
 638                 g = load_commit_graph_chain(r, odb);
 639
 640         validate_mixed_generation_chain(g);
 641
 642         return g;
 643 }
 644
 645 static void prepare_commit_graph_one(struct repository *r,
 646                                      struct object_directory *odb)
 647 {
 648
 649         if (r->objects->commit_graph)
 650                 return;
 651
 652         r->objects->commit_graph = read_commit_graph_one(r, odb);
 653 }
 654
 655 /*
 656  * Return 1 if commit_graph is non-NULL, and 0 otherwise.
 657  *
 658  * On the first invocation, this function attempts to load the commit
 659  * graph if the_repository is configured to have one.
 660  */
 661 static int prepare_commit_graph(struct repository *r)
 662 {
 663         struct object_directory *odb;
 664
 665         /*
 666          * This must come before the "already attempted?" check below, because
 667          * we want to disable even an already-loaded graph file.
 668          */
 669         if (r->commit_graph_disabled)
 670                 return 0;
 671
 672         if (r->objects->commit_graph_attempted)
 673                 return !!r->objects->commit_graph;
 674         r->objects->commit_graph_attempted = 1;
 675
 676         prepare_repo_settings(r);
 677
 678         if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
 679             r->settings.core_commit_graph != 1)
 680                 /*
 681                  * This repository is not configured to use commit graphs, so
 682                  * do not load one. (But report commit_graph_attempted anyway
 683                  * so that commit graph loading is not attempted again for this
 684                  * repository.)
 685                  */
 686                 return 0;
 687
 688         if (!commit_graph_compatible(r))
 689                 return 0;
 690
 691         prepare_alt_odb(r);
 692         for (odb = r->objects->odb;
 693              !r->objects->commit_graph && odb;
 694              odb = odb->next)
 695                 prepare_commit_graph_one(r, odb);
 696         return !!r->objects->commit_graph;
 697 }
 698
 699 int generation_numbers_enabled(struct repository *r)
 700 {
 701         uint32_t first_generation;
 702         struct commit_graph *g;
 703         if (!prepare_commit_graph(r))
 704                return 0;
 705
 706         g = r->objects->commit_graph;
 707
 708         if (!g->num_commits)
 709                 return 0;
 710
 711         first_generation = get_be32(g->chunk_commit_data +
 712                                     g->hash_len + 8) >> 2;
 713
 714         return !!first_generation;
 715 }
 716
 717 int corrected_commit_dates_enabled(struct repository *r)
 718 {
 719         struct commit_graph *g;
 720         if (!prepare_commit_graph(r))
 721                 return 0;
 722
 723         g = r->objects->commit_graph;
 724
 725         if (!g->num_commits)
 726                 return 0;
 727
 728         return g->read_generation_data;
 729 }
 730
 731 struct bloom_filter_settings *get_bloom_filter_settings(struct repository *r)
 732 {
 733         struct commit_graph *g = r->objects->commit_graph;
 734         while (g) {
 735                 if (g->bloom_filter_settings)
 736                         return g->bloom_filter_settings;
 737                 g = g->base_graph;
 738         }
 739         return NULL;
 740 }
 741
 742 static void close_commit_graph_one(struct commit_graph *g)
 743 {
 744         if (!g)
 745                 return;
 746
 747         close_commit_graph_one(g->base_graph);
 748         free_commit_graph(g);
 749 }
 750
 751 void close_commit_graph(struct raw_object_store *o)
 752 {
 753         close_commit_graph_one(o->commit_graph);
 754         o->commit_graph = NULL;
 755 }
 756
 757 static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
 758 {
 759         return bsearch_hash(oid->hash, g->chunk_oid_fanout,
 760                             g->chunk_oid_lookup, g->hash_len, pos);
 761 }
 762
 763 static void load_oid_from_graph(struct commit_graph *g,
 764                                 uint32_t pos,
 765                                 struct object_id *oid)
 766 {
 767         uint32_t lex_index;
 768
 769         while (g && pos < g->num_commits_in_base)
 770                 g = g->base_graph;
 771
 772         if (!g)
 773                 BUG("NULL commit-graph");
 774
 775         if (pos >= g->num_commits + g->num_commits_in_base)
 776                 die(_("invalid commit position. commit-graph is likely corrupt"));
 777
 778         lex_index = pos - g->num_commits_in_base;
 779
 780         hashcpy(oid->hash, g->chunk_oid_lookup + g->hash_len * lex_index);
 781 }
 782
 783 static struct commit_list **insert_parent_or_die(struct repository *r,
 784                                                  struct commit_graph *g,
 785                                                  uint32_t pos,
 786                                                  struct commit_list **pptr)
 787 {
 788         struct commit *c;
 789         struct object_id oid;
 790
 791         if (pos >= g->num_commits + g->num_commits_in_base)
 792                 die("invalid parent position %"PRIu32, pos);
 793
 794         load_oid_from_graph(g, pos, &oid);
 795         c = lookup_commit(r, &oid);
 796         if (!c)
 797                 die(_("could not find commit %s"), oid_to_hex(&oid));
 798         commit_graph_data_at(c)->graph_pos = pos;
 799         return &commit_list_insert(c, pptr)->next;
 800 }
 801
 802 static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
 803 {
 804         const unsigned char *commit_data;
 805         struct commit_graph_data *graph_data;
 806         uint32_t lex_index, offset_pos;
 807         uint64_t date_high, date_low, offset;
 808
 809         while (pos < g->num_commits_in_base)
 810                 g = g->base_graph;
 811
 812         if (pos >= g->num_commits + g->num_commits_in_base)
 813                 die(_("invalid commit position. commit-graph is likely corrupt"));
 814
 815         lex_index = pos - g->num_commits_in_base;
 816         commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * lex_index;
 817
 818         graph_data = commit_graph_data_at(item);
 819         graph_data->graph_pos = pos;
 820
 821         date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
 822         date_low = get_be32(commit_data + g->hash_len + 12);
 823         item->date = (timestamp_t)((date_high << 32) | date_low);
 824
 825         if (g->read_generation_data) {
 826                 offset = (timestamp_t)get_be32(g->chunk_generation_data + sizeof(uint32_t) * lex_index);
 827
 828                 if (offset & CORRECTED_COMMIT_DATE_OFFSET_OVERFLOW) {
 829                         if (!g->chunk_generation_data_overflow)
 830                                 die(_("commit-graph requires overflow generation data but has none"));
 831
 832                         offset_pos = offset ^ CORRECTED_COMMIT_DATE_OFFSET_OVERFLOW;
 833                         graph_data->generation = get_be64(g->chunk_generation_data_overflow + 8 * offset_pos);
 834                 } else
 835                         graph_data->generation = item->date + offset;
 836         } else
 837                 graph_data->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 838
 839         if (g->topo_levels)
 840                 *topo_level_slab_at(g->topo_levels, item) = get_be32(commit_data + g->hash_len + 8) >> 2;
 841 }
 842
 843 static inline void set_commit_tree(struct commit *c, struct tree *t)
 844 {
 845         c->maybe_tree = t;
 846 }
 847
 848 static int fill_commit_in_graph(struct repository *r,
 849                                 struct commit *item,
 850                                 struct commit_graph *g, uint32_t pos)
 851 {
 852         uint32_t edge_value;
 853         uint32_t *parent_data_ptr;
 854         struct commit_list **pptr;
 855         const unsigned char *commit_data;
 856         uint32_t lex_index;
 857
 858         while (pos < g->num_commits_in_base)
 859                 g = g->base_graph;
 860
 861         fill_commit_graph_info(item, g, pos);
 862
 863         lex_index = pos - g->num_commits_in_base;
 864         commit_data = g->chunk_commit_data + (g->hash_len + 16) * lex_index;
 865
 866         item->object.parsed = 1;
 867
 868         set_commit_tree(item, NULL);
 869
 870         pptr = &item->parents;
 871
 872         edge_value = get_be32(commit_data + g->hash_len);
 873         if (edge_value == GRAPH_PARENT_NONE)
 874                 return 1;
 875         pptr = insert_parent_or_die(r, g, edge_value, pptr);
 876
 877         edge_value = get_be32(commit_data + g->hash_len + 4);
 878         if (edge_value == GRAPH_PARENT_NONE)
 879                 return 1;
 880         if (!(edge_value & GRAPH_EXTRA_EDGES_NEEDED)) {
 881                 pptr = insert_parent_or_die(r, g, edge_value, pptr);
 882                 return 1;
 883         }
 884
 885         parent_data_ptr = (uint32_t*)(g->chunk_extra_edges +
 886                           4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
 887         do {
 888                 edge_value = get_be32(parent_data_ptr);
 889                 pptr = insert_parent_or_die(r, g,
 890                                             edge_value & GRAPH_EDGE_LAST_MASK,
 891                                             pptr);
 892                 parent_data_ptr++;
 893         } while (!(edge_value & GRAPH_LAST_EDGE));
 894
 895         return 1;
 896 }
 897
 898 static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 899 {
 900         uint32_t graph_pos = commit_graph_position(item);
 901         if (graph_pos != COMMIT_NOT_FROM_GRAPH) {
 902                 *pos = graph_pos;
 903                 return 1;
 904         } else {
 905                 struct commit_graph *cur_g = g;
 906                 uint32_t lex_index;
 907
 908                 while (cur_g && !bsearch_graph(cur_g, &(item->object.oid), &lex_index))
 909                         cur_g = cur_g->base_graph;
 910
 911                 if (cur_g) {
 912                         *pos = lex_index + cur_g->num_commits_in_base;
 913                         return 1;
 914                 }
 915
 916                 return 0;
 917         }
 918 }
 919
 920 static int parse_commit_in_graph_one(struct repository *r,
 921                                      struct commit_graph *g,
 922                                      struct commit *item)
 923 {
 924         uint32_t pos;
 925
 926         if (item->object.parsed)
 927                 return 1;
 928
 929         if (find_commit_in_graph(item, g, &pos))
 930                 return fill_commit_in_graph(r, item, g, pos);
 931
 932         return 0;
 933 }
 934
 935 int parse_commit_in_graph(struct repository *r, struct commit *item)
 936 {
 937         static int checked_env = 0;
 938
 939         if (!checked_env &&
 940             git_env_bool(GIT_TEST_COMMIT_GRAPH_DIE_ON_PARSE, 0))
 941                 die("dying as requested by the '%s' variable on commit-graph parse!",
 942                     GIT_TEST_COMMIT_GRAPH_DIE_ON_PARSE);
 943         checked_env = 1;
 944
 945         if (!prepare_commit_graph(r))
 946                 return 0;
 947         return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
 948 }
 949
 950 void load_commit_graph_info(struct repository *r, struct commit *item)
 951 {
 952         uint32_t pos;
 953         if (!prepare_commit_graph(r))
 954                 return;
 955         if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
 956                 fill_commit_graph_info(item, r->objects->commit_graph, pos);
 957 }
 958
 959 static struct tree *load_tree_for_commit(struct repository *r,
 960                                          struct commit_graph *g,
 961                                          struct commit *c)
 962 {
 963         struct object_id oid;
 964         const unsigned char *commit_data;
 965         uint32_t graph_pos = commit_graph_position(c);
 966
 967         while (graph_pos < g->num_commits_in_base)
 968                 g = g->base_graph;
 969
 970         commit_data = g->chunk_commit_data +
 971                         GRAPH_DATA_WIDTH * (graph_pos - g->num_commits_in_base);
 972
 973         hashcpy(oid.hash, commit_data);
 974         set_commit_tree(c, lookup_tree(r, &oid));
 975
 976         return c->maybe_tree;
 977 }
 978
 979 static struct tree *get_commit_tree_in_graph_one(struct repository *r,
 980                                                  struct commit_graph *g,
 981                                                  const struct commit *c)
 982 {
 983         if (c->maybe_tree)
 984                 return c->maybe_tree;
 985         if (commit_graph_position(c) == COMMIT_NOT_FROM_GRAPH)
 986                 BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
 987
 988         return load_tree_for_commit(r, g, (struct commit *)c);
 989 }
 990
 991 struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
 992 {
 993         return get_commit_tree_in_graph_one(r, r->objects->commit_graph, c);
 994 }
 995
 996 struct packed_commit_list {
 997         struct commit **list;
 998         size_t nr;
 999         size_t alloc;
1000 };
1001
1002 struct write_commit_graph_context {
1003         struct repository *r;
1004         struct object_directory *odb;
1005         char *graph_name;
1006         struct oid_array oids;
1007         struct packed_commit_list commits;
1008         int num_extra_edges;
1009         int num_generation_data_overflows;
1010         unsigned long approx_nr_objects;
1011         struct progress *progress;
1012         int progress_done;
1013         uint64_t progress_cnt;
1014
1015         char *base_graph_name;
1016         int num_commit_graphs_before;
1017         int num_commit_graphs_after;
1018         char **commit_graph_filenames_before;
1019         char **commit_graph_filenames_after;
1020         char **commit_graph_hash_after;
1021         uint32_t new_num_commits_in_base;
1022         struct commit_graph *new_base_graph;
1023
1024         unsigned append:1,
1025                  report_progress:1,
1026                  split:1,
1027                  changed_paths:1,
1028                  order_by_pack:1,
1029                  write_generation_data:1;
1030
1031         struct topo_level_slab *topo_levels;
1032         const struct commit_graph_opts *opts;
1033         size_t total_bloom_filter_data_size;
1034         const struct bloom_filter_settings *bloom_settings;
1035
1036         int count_bloom_filter_computed;
1037         int count_bloom_filter_not_computed;
1038         int count_bloom_filter_trunc_empty;
1039         int count_bloom_filter_trunc_large;
1040 };
1041
1042 static int write_graph_chunk_fanout(struct hashfile *f,
1043                                     void *data)
1044 {
1045         struct write_commit_graph_context *ctx = data;
1046         int i, count = 0;
1047         struct commit **list = ctx->commits.list;
1048
1049         /*
1050          * Write the first-level table (the list is sorted,
1051          * but we use a 256-entry lookup to be able to avoid
1052          * having to do eight extra binary search iterations).
1053          */
1054         for (i = 0; i < 256; i++) {
1055                 while (count < ctx->commits.nr) {
1056                         if ((*list)->object.oid.hash[0] != i)
1057                                 break;
1058                         display_progress(ctx->progress, ++ctx->progress_cnt);
1059                         count++;
1060                         list++;
1061                 }
1062
1063                 hashwrite_be32(f, count);
1064         }
1065
1066         return 0;
1067 }
1068
1069 static int write_graph_chunk_oids(struct hashfile *f,
1070                                   void *data)
1071 {
1072         struct write_commit_graph_context *ctx = data;
1073         struct commit **list = ctx->commits.list;
1074         int count;
1075         for (count = 0; count < ctx->commits.nr; count++, list++) {
1076                 display_progress(ctx->progress, ++ctx->progress_cnt);
1077                 hashwrite(f, (*list)->object.oid.hash, the_hash_algo->rawsz);
1078         }
1079
1080         return 0;
1081 }
1082
1083 static const unsigned char *commit_to_sha1(size_t index, void *table)
1084 {
1085         struct commit **commits = table;
1086         return commits[index]->object.oid.hash;
1087 }
1088
1089 static int write_graph_chunk_data(struct hashfile *f,
1090                                   void *data)
1091 {
1092         struct write_commit_graph_context *ctx = data;
1093         struct commit **list = ctx->commits.list;
1094         struct commit **last = ctx->commits.list + ctx->commits.nr;
1095         uint32_t num_extra_edges = 0;
1096
1097         while (list < last) {
1098                 struct commit_list *parent;
1099                 struct object_id *tree;
1100                 int edge_value;
1101                 uint32_t packedDate[2];
1102                 display_progress(ctx->progress, ++ctx->progress_cnt);
1103
1104                 if (parse_commit_no_graph(*list))
1105                         die(_("unable to parse commit %s"),
1106                                 oid_to_hex(&(*list)->object.oid));
1107                 tree = get_commit_tree_oid(*list);
1108                 hashwrite(f, tree->hash, the_hash_algo->rawsz);
1109
1110                 parent = (*list)->parents;
1111
1112                 if (!parent)
1113                         edge_value = GRAPH_PARENT_NONE;
1114                 else {
1115                         edge_value = sha1_pos(parent->item->object.oid.hash,
1116                                               ctx->commits.list,
1117                                               ctx->commits.nr,
1118                                               commit_to_sha1);
1119
1120                         if (edge_value >= 0)
1121                                 edge_value += ctx->new_num_commits_in_base;
1122                         else if (ctx->new_base_graph) {
1123                                 uint32_t pos;
1124                                 if (find_commit_in_graph(parent->item,
1125                                                          ctx->new_base_graph,
1126                                                          &pos))
1127                                         edge_value = pos;
1128                         }
1129
1130                         if (edge_value < 0)
1131                                 BUG("missing parent %s for commit %s",
1132                                     oid_to_hex(&parent->item->object.oid),
1133                                     oid_to_hex(&(*list)->object.oid));
1134                 }
1135
1136                 hashwrite_be32(f, edge_value);
1137
1138                 if (parent)
1139                         parent = parent->next;
1140
1141                 if (!parent)
1142                         edge_value = GRAPH_PARENT_NONE;
1143                 else if (parent->next)
1144                         edge_value = GRAPH_EXTRA_EDGES_NEEDED | num_extra_edges;
1145                 else {
1146                         edge_value = sha1_pos(parent->item->object.oid.hash,
1147                                               ctx->commits.list,
1148                                               ctx->commits.nr,
1149                                               commit_to_sha1);
1150
1151                         if (edge_value >= 0)
1152                                 edge_value += ctx->new_num_commits_in_base;
1153                         else if (ctx->new_base_graph) {
1154                                 uint32_t pos;
1155                                 if (find_commit_in_graph(parent->item,
1156                                                          ctx->new_base_graph,
1157                                                          &pos))
1158                                         edge_value = pos;
1159                         }
1160
1161                         if (edge_value < 0)
1162                                 BUG("missing parent %s for commit %s",
1163                                     oid_to_hex(&parent->item->object.oid),
1164                                     oid_to_hex(&(*list)->object.oid));
1165                 }
1166
1167                 hashwrite_be32(f, edge_value);
1168
1169                 if (edge_value & GRAPH_EXTRA_EDGES_NEEDED) {
1170                         do {
1171                                 num_extra_edges++;
1172                                 parent = parent->next;
1173                         } while (parent);
1174                 }
1175
1176                 if (sizeof((*list)->date) > 4)
1177                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
1178                 else
1179                         packedDate[0] = 0;
1180
1181                 packedDate[0] |= htonl(*topo_level_slab_at(ctx->topo_levels, *list) << 2);
1182
1183                 packedDate[1] = htonl((*list)->date);
1184                 hashwrite(f, packedDate, 8);
1185
1186                 list++;
1187         }
1188
1189         return 0;
1190 }
1191
1192 static int write_graph_chunk_generation_data(struct hashfile *f,
1193                                              void *data)
1194 {
1195         struct write_commit_graph_context *ctx = data;
1196         int i, num_generation_data_overflows = 0;
1197
1198         for (i = 0; i < ctx->commits.nr; i++) {
1199                 struct commit *c = ctx->commits.list[i];
1200                 timestamp_t offset = commit_graph_data_at(c)->generation - c->date;
1201                 display_progress(ctx->progress, ++ctx->progress_cnt);
1202
1203                 if (offset > GENERATION_NUMBER_V2_OFFSET_MAX) {
1204                         offset = CORRECTED_COMMIT_DATE_OFFSET_OVERFLOW | num_generation_data_overflows;
1205                         num_generation_data_overflows++;
1206                 }
1207
1208                 hashwrite_be32(f, offset);
1209         }
1210
1211         return 0;
1212 }
1213
1214 static int write_graph_chunk_generation_data_overflow(struct hashfile *f,
1215                                                       void *data)
1216 {
1217         struct write_commit_graph_context *ctx = data;
1218         int i;
1219         for (i = 0; i < ctx->commits.nr; i++) {
1220                 struct commit *c = ctx->commits.list[i];
1221                 timestamp_t offset = commit_graph_data_at(c)->generation - c->date;
1222                 display_progress(ctx->progress, ++ctx->progress_cnt);
1223
1224                 if (offset > GENERATION_NUMBER_V2_OFFSET_MAX) {
1225                         hashwrite_be32(f, offset >> 32);
1226                         hashwrite_be32(f, (uint32_t) offset);
1227                 }
1228         }
1229
1230         return 0;
1231 }
1232
1233 static int write_graph_chunk_extra_edges(struct hashfile *f,
1234                                          void *data)
1235 {
1236         struct write_commit_graph_context *ctx = data;
1237         struct commit **list = ctx->commits.list;
1238         struct commit **last = ctx->commits.list + ctx->commits.nr;
1239         struct commit_list *parent;
1240
1241         while (list < last) {
1242                 int num_parents = 0;
1243
1244                 display_progress(ctx->progress, ++ctx->progress_cnt);
1245
1246                 for (parent = (*list)->parents; num_parents < 3 && parent;
1247                      parent = parent->next)
1248                         num_parents++;
1249
1250                 if (num_parents <= 2) {
1251                         list++;
1252                         continue;
1253                 }
1254
1255                 /* Since num_parents > 2, this initializer is safe. */
1256                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
1257                         int edge_value = sha1_pos(parent->item->object.oid.hash,
1258                                                   ctx->commits.list,
1259                                                   ctx->commits.nr,
1260                                                   commit_to_sha1);
1261
1262                         if (edge_value >= 0)
1263                                 edge_value += ctx->new_num_commits_in_base;
1264                         else if (ctx->new_base_graph) {
1265                                 uint32_t pos;
1266                                 if (find_commit_in_graph(parent->item,
1267                                                          ctx->new_base_graph,
1268                                                          &pos))
1269                                         edge_value = pos;
1270                         }
1271
1272                         if (edge_value < 0)
1273                                 BUG("missing parent %s for commit %s",
1274                                     oid_to_hex(&parent->item->object.oid),
1275                                     oid_to_hex(&(*list)->object.oid));
1276                         else if (!parent->next)
1277                                 edge_value |= GRAPH_LAST_EDGE;
1278
1279                         hashwrite_be32(f, edge_value);
1280                 }
1281
1282                 list++;
1283         }
1284
1285         return 0;
1286 }
1287
1288 static int write_graph_chunk_bloom_indexes(struct hashfile *f,
1289                                            void *data)
1290 {
1291         struct write_commit_graph_context *ctx = data;
1292         struct commit **list = ctx->commits.list;
1293         struct commit **last = ctx->commits.list + ctx->commits.nr;
1294         uint32_t cur_pos = 0;
1295
1296         while (list < last) {
1297                 struct bloom_filter *filter = get_bloom_filter(ctx->r, *list);
1298                 size_t len = filter ? filter->len : 0;
1299                 cur_pos += len;
1300                 display_progress(ctx->progress, ++ctx->progress_cnt);
1301                 hashwrite_be32(f, cur_pos);
1302                 list++;
1303         }
1304
1305         return 0;
1306 }
1307
1308 static void trace2_bloom_filter_settings(struct write_commit_graph_context *ctx)
1309 {
1310         struct json_writer jw = JSON_WRITER_INIT;
1311
1312         jw_object_begin(&jw, 0);
1313         jw_object_intmax(&jw, "hash_version", ctx->bloom_settings->hash_version);
1314         jw_object_intmax(&jw, "num_hashes", ctx->bloom_settings->num_hashes);
1315         jw_object_intmax(&jw, "bits_per_entry", ctx->bloom_settings->bits_per_entry);
1316         jw_object_intmax(&jw, "max_changed_paths", ctx->bloom_settings->max_changed_paths);
1317         jw_end(&jw);
1318
1319         trace2_data_json("bloom", ctx->r, "settings", &jw);
1320
1321         jw_release(&jw);
1322 }
1323
1324 static int write_graph_chunk_bloom_data(struct hashfile *f,
1325                                         void *data)
1326 {
1327         struct write_commit_graph_context *ctx = data;
1328         struct commit **list = ctx->commits.list;
1329         struct commit **last = ctx->commits.list + ctx->commits.nr;
1330
1331         trace2_bloom_filter_settings(ctx);
1332
1333         hashwrite_be32(f, ctx->bloom_settings->hash_version);
1334         hashwrite_be32(f, ctx->bloom_settings->num_hashes);
1335         hashwrite_be32(f, ctx->bloom_settings->bits_per_entry);
1336
1337         while (list < last) {
1338                 struct bloom_filter *filter = get_bloom_filter(ctx->r, *list);
1339                 size_t len = filter ? filter->len : 0;
1340
1341                 display_progress(ctx->progress, ++ctx->progress_cnt);
1342                 if (len)
1343                         hashwrite(f, filter->data, len * sizeof(unsigned char));
1344                 list++;
1345         }
1346
1347         return 0;
1348 }
1349
1350 static int add_packed_commits(const struct object_id *oid,
1351                               struct packed_git *pack,
1352                               uint32_t pos,
1353                               void *data)
1354 {
1355         struct write_commit_graph_context *ctx = (struct write_commit_graph_context*)data;
1356         enum object_type type;
1357         off_t offset = nth_packed_object_offset(pack, pos);
1358         struct object_info oi = OBJECT_INFO_INIT;
1359
1360         if (ctx->progress)
1361                 display_progress(ctx->progress, ++ctx->progress_done);
1362
1363         oi.typep = &type;
1364         if (packed_object_info(ctx->r, pack, offset, &oi) < 0)
1365                 die(_("unable to get type of object %s"), oid_to_hex(oid));
1366
1367         if (type != OBJ_COMMIT)
1368                 return 0;
1369
1370         oid_array_append(&ctx->oids, oid);
1371         set_commit_pos(ctx->r, oid);
1372
1373         return 0;
1374 }
1375
1376 static void add_missing_parents(struct write_commit_graph_context *ctx, struct commit *commit)
1377 {
1378         struct commit_list *parent;
1379         for (parent = commit->parents; parent; parent = parent->next) {
1380                 if (!(parent->item->object.flags & REACHABLE)) {
1381                         oid_array_append(&ctx->oids, &parent->item->object.oid);
1382                         parent->item->object.flags |= REACHABLE;
1383                 }
1384         }
1385 }
1386
1387 static void close_reachable(struct write_commit_graph_context *ctx)
1388 {
1389         int i;
1390         struct commit *commit;
1391         enum commit_graph_split_flags flags = ctx->opts ?
1392                 ctx->opts->split_flags : COMMIT_GRAPH_SPLIT_UNSPECIFIED;
1393
1394         if (ctx->report_progress)
1395                 ctx->progress = start_delayed_progress(
1396                                         _("Loading known commits in commit graph"),
1397                                         ctx->oids.nr);
1398         for (i = 0; i < ctx->oids.nr; i++) {
1399                 display_progress(ctx->progress, i + 1);
1400                 commit = lookup_commit(ctx->r, &ctx->oids.oid[i]);
1401                 if (commit)
1402                         commit->object.flags |= REACHABLE;
1403         }
1404         stop_progress(&ctx->progress);
1405
1406         /*
1407          * As this loop runs, ctx->oids.nr may grow, but not more
1408          * than the number of missing commits in the reachable
1409          * closure.
1410          */
1411         if (ctx->report_progress)
1412                 ctx->progress = start_delayed_progress(
1413                                         _("Expanding reachable commits in commit graph"),
1414                                         0);
1415         for (i = 0; i < ctx->oids.nr; i++) {
1416                 display_progress(ctx->progress, i + 1);
1417                 commit = lookup_commit(ctx->r, &ctx->oids.oid[i]);
1418
1419                 if (!commit)
1420                         continue;
1421                 if (ctx->split) {
1422                         if ((!parse_commit(commit) &&
1423                              commit_graph_position(commit) == COMMIT_NOT_FROM_GRAPH) ||
1424                             flags == COMMIT_GRAPH_SPLIT_REPLACE)
1425                                 add_missing_parents(ctx, commit);
1426                 } else if (!parse_commit_no_graph(commit))
1427                         add_missing_parents(ctx, commit);
1428         }
1429         stop_progress(&ctx->progress);
1430
1431         if (ctx->report_progress)
1432                 ctx->progress = start_delayed_progress(
1433                                         _("Clearing commit marks in commit graph"),
1434                                         ctx->oids.nr);
1435         for (i = 0; i < ctx->oids.nr; i++) {
1436                 display_progress(ctx->progress, i + 1);
1437                 commit = lookup_commit(ctx->r, &ctx->oids.oid[i]);
1438
1439                 if (commit)
1440                         commit->object.flags &= ~REACHABLE;
1441         }
1442         stop_progress(&ctx->progress);
1443 }
1444
1445 static void compute_generation_numbers(struct write_commit_graph_context *ctx)
1446 {
1447         int i;
1448         struct commit_list *list = NULL;
1449
1450         if (ctx->report_progress)
1451                 ctx->progress = start_delayed_progress(
1452                                         _("Computing commit graph generation numbers"),
1453                                         ctx->commits.nr);
1454         for (i = 0; i < ctx->commits.nr; i++) {
1455                 uint32_t level = *topo_level_slab_at(ctx->topo_levels, ctx->commits.list[i]);
1456                 timestamp_t corrected_commit_date = commit_graph_data_at(ctx->commits.list[i])->generation;
1457
1458                 display_progress(ctx->progress, i + 1);
1459                 if (level != GENERATION_NUMBER_ZERO &&
1460                     corrected_commit_date != GENERATION_NUMBER_ZERO)
1461                         continue;
1462
1463                 commit_list_insert(ctx->commits.list[i], &list);
1464                 while (list) {
1465                         struct commit *current = list->item;
1466                         struct commit_list *parent;
1467                         int all_parents_computed = 1;
1468                         uint32_t max_level = 0;
1469                         timestamp_t max_corrected_commit_date = 0;
1470
1471                         for (parent = current->parents; parent; parent = parent->next) {
1472                                 level = *topo_level_slab_at(ctx->topo_levels, parent->item);
1473                                 corrected_commit_date = commit_graph_data_at(parent->item)->generation;
1474
1475                                 if (level == GENERATION_NUMBER_ZERO ||
1476                                     corrected_commit_date == GENERATION_NUMBER_ZERO) {
1477                                         all_parents_computed = 0;
1478                                         commit_list_insert(parent->item, &list);
1479                                         break;
1480                                 }
1481
1482                                 if (level > max_level)
1483                                         max_level = level;
1484
1485                                 if (corrected_commit_date > max_corrected_commit_date)
1486                                         max_corrected_commit_date = corrected_commit_date;
1487                         }
1488
1489                         if (all_parents_computed) {
1490                                 pop_commit(&list);
1491
1492                                 if (max_level > GENERATION_NUMBER_V1_MAX - 1)
1493                                         max_level = GENERATION_NUMBER_V1_MAX - 1;
1494                                 *topo_level_slab_at(ctx->topo_levels, current) = max_level + 1;
1495
1496                                 if (current->date && current->date > max_corrected_commit_date)
1497                                         max_corrected_commit_date = current->date - 1;
1498                                 commit_graph_data_at(current)->generation = max_corrected_commit_date + 1;
1499
1500                                 if (commit_graph_data_at(current)->generation - current->date > GENERATION_NUMBER_V2_OFFSET_MAX)
1501                                         ctx->num_generation_data_overflows++;
1502                         }
1503                 }
1504         }
1505         stop_progress(&ctx->progress);
1506 }
1507
1508 static void trace2_bloom_filter_write_statistics(struct write_commit_graph_context *ctx)
1509 {
1510         trace2_data_intmax("commit-graph", ctx->r, "filter-computed",
1511                            ctx->count_bloom_filter_computed);
1512         trace2_data_intmax("commit-graph", ctx->r, "filter-not-computed",
1513                            ctx->count_bloom_filter_not_computed);
1514         trace2_data_intmax("commit-graph", ctx->r, "filter-trunc-empty",
1515                            ctx->count_bloom_filter_trunc_empty);
1516         trace2_data_intmax("commit-graph", ctx->r, "filter-trunc-large",
1517                            ctx->count_bloom_filter_trunc_large);
1518 }
1519
1520 static void compute_bloom_filters(struct write_commit_graph_context *ctx)
1521 {
1522         int i;
1523         struct progress *progress = NULL;
1524         struct commit **sorted_commits;
1525         int max_new_filters;
1526
1527         init_bloom_filters();
1528
1529         if (ctx->report_progress)
1530                 progress = start_delayed_progress(
1531                         _("Computing commit changed paths Bloom filters"),
1532                         ctx->commits.nr);
1533
1534         ALLOC_ARRAY(sorted_commits, ctx->commits.nr);
1535         COPY_ARRAY(sorted_commits, ctx->commits.list, ctx->commits.nr);
1536
1537         if (ctx->order_by_pack)
1538                 QSORT(sorted_commits, ctx->commits.nr, commit_pos_cmp);
1539         else
1540                 QSORT(sorted_commits, ctx->commits.nr, commit_gen_cmp);
1541
1542         max_new_filters = ctx->opts && ctx->opts->max_new_filters >= 0 ?
1543                 ctx->opts->max_new_filters : ctx->commits.nr;
1544
1545         for (i = 0; i < ctx->commits.nr; i++) {
1546                 enum bloom_filter_computed computed = 0;
1547                 struct commit *c = sorted_commits[i];
1548                 struct bloom_filter *filter = get_or_compute_bloom_filter(
1549                         ctx->r,
1550                         c,
1551                         ctx->count_bloom_filter_computed < max_new_filters,
1552                         ctx->bloom_settings,
1553                         &computed);
1554                 if (computed & BLOOM_COMPUTED) {
1555                         ctx->count_bloom_filter_computed++;
1556                         if (computed & BLOOM_TRUNC_EMPTY)
1557                                 ctx->count_bloom_filter_trunc_empty++;
1558                         if (computed & BLOOM_TRUNC_LARGE)
1559                                 ctx->count_bloom_filter_trunc_large++;
1560                 } else if (computed & BLOOM_NOT_COMPUTED)
1561                         ctx->count_bloom_filter_not_computed++;
1562                 ctx->total_bloom_filter_data_size += filter
1563                         ? sizeof(unsigned char) * filter->len : 0;
1564                 display_progress(progress, i + 1);
1565         }
1566
1567         if (trace2_is_enabled())
1568                 trace2_bloom_filter_write_statistics(ctx);
1569
1570         free(sorted_commits);
1571         stop_progress(&progress);
1572 }
1573
1574 struct refs_cb_data {
1575         struct oidset *commits;
1576         struct progress *progress;
1577 };
1578
1579 static int add_ref_to_set(const char *refname,
1580                           const struct object_id *oid,
1581                           int flags, void *cb_data)
1582 {
1583         struct object_id peeled;
1584         struct refs_cb_data *data = (struct refs_cb_data *)cb_data;
1585
1586         if (!peel_ref(refname, &peeled))
1587                 oid = &peeled;
1588         if (oid_object_info(the_repository, oid, NULL) == OBJ_COMMIT)
1589                 oidset_insert(data->commits, oid);
1590
1591         display_progress(data->progress, oidset_size(data->commits));
1592
1593         return 0;
1594 }
1595
1596 int write_commit_graph_reachable(struct object_directory *odb,
1597                                  enum commit_graph_write_flags flags,
1598                                  const struct commit_graph_opts *opts)
1599 {
1600         struct oidset commits = OIDSET_INIT;
1601         struct refs_cb_data data;
1602         int result;
1603
1604         memset(&data, 0, sizeof(data));
1605         data.commits = &commits;
1606         if (flags & COMMIT_GRAPH_WRITE_PROGRESS)
1607                 data.progress = start_delayed_progress(
1608                         _("Collecting referenced commits"), 0);
1609
1610         for_each_ref(add_ref_to_set, &data);
1611
1612         stop_progress(&data.progress);
1613
1614         result = write_commit_graph(odb, NULL, &commits,
1615                                     flags, opts);
1616
1617         oidset_clear(&commits);
1618         return result;
1619 }
1620
1621 static int fill_oids_from_packs(struct write_commit_graph_context *ctx,
1622                                 struct string_list *pack_indexes)
1623 {
1624         uint32_t i;
1625         struct strbuf progress_title = STRBUF_INIT;
1626         struct strbuf packname = STRBUF_INIT;
1627         int dirlen;
1628
1629         strbuf_addf(&packname, "%s/pack/", ctx->odb->path);
1630         dirlen = packname.len;
1631         if (ctx->report_progress) {
1632                 strbuf_addf(&progress_title,
1633                             Q_("Finding commits for commit graph in %d pack",
1634                                "Finding commits for commit graph in %d packs",
1635                                pack_indexes->nr),
1636                             pack_indexes->nr);
1637                 ctx->progress = start_delayed_progress(progress_title.buf, 0);
1638                 ctx->progress_done = 0;
1639         }
1640         for (i = 0; i < pack_indexes->nr; i++) {
1641                 struct packed_git *p;
1642                 strbuf_setlen(&packname, dirlen);
1643                 strbuf_addstr(&packname, pack_indexes->items[i].string);
1644                 p = add_packed_git(packname.buf, packname.len, 1);
1645                 if (!p) {
1646                         error(_("error adding pack %s"), packname.buf);
1647                         return -1;
1648                 }
1649                 if (open_pack_index(p)) {
1650                         error(_("error opening index for %s"), packname.buf);
1651                         return -1;
1652                 }
1653                 for_each_object_in_pack(p, add_packed_commits, ctx,
1654                                         FOR_EACH_OBJECT_PACK_ORDER);
1655                 close_pack(p);
1656                 free(p);
1657         }
1658
1659         stop_progress(&ctx->progress);
1660         strbuf_release(&progress_title);
1661         strbuf_release(&packname);
1662
1663         return 0;
1664 }
1665
1666 static int fill_oids_from_commits(struct write_commit_graph_context *ctx,
1667                                   struct oidset *commits)
1668 {
1669         struct oidset_iter iter;
1670         struct object_id *oid;
1671
1672         if (!oidset_size(commits))
1673                 return 0;
1674
1675         oidset_iter_init(commits, &iter);
1676         while ((oid = oidset_iter_next(&iter))) {
1677                 oid_array_append(&ctx->oids, oid);
1678         }
1679
1680         return 0;
1681 }
1682
1683 static void fill_oids_from_all_packs(struct write_commit_graph_context *ctx)
1684 {
1685         if (ctx->report_progress)
1686                 ctx->progress = start_delayed_progress(
1687                         _("Finding commits for commit graph among packed objects"),
1688                         ctx->approx_nr_objects);
1689         for_each_packed_object(add_packed_commits, ctx,
1690                                FOR_EACH_OBJECT_PACK_ORDER);
1691         if (ctx->progress_done < ctx->approx_nr_objects)
1692                 display_progress(ctx->progress, ctx->approx_nr_objects);
1693         stop_progress(&ctx->progress);
1694 }
1695
1696 static void copy_oids_to_commits(struct write_commit_graph_context *ctx)
1697 {
1698         uint32_t i;
1699         enum commit_graph_split_flags flags = ctx->opts ?
1700                 ctx->opts->split_flags : COMMIT_GRAPH_SPLIT_UNSPECIFIED;
1701
1702         ctx->num_extra_edges = 0;
1703         if (ctx->report_progress)
1704                 ctx->progress = start_delayed_progress(
1705                         _("Finding extra edges in commit graph"),
1706                         ctx->oids.nr);
1707         oid_array_sort(&ctx->oids);
1708         for (i = 0; i < ctx->oids.nr; i = oid_array_next_unique(&ctx->oids, i)) {
1709                 unsigned int num_parents;
1710
1711                 display_progress(ctx->progress, i + 1);
1712
1713                 ALLOC_GROW(ctx->commits.list, ctx->commits.nr + 1, ctx->commits.alloc);
1714                 ctx->commits.list[ctx->commits.nr] = lookup_commit(ctx->r, &ctx->oids.oid[i]);
1715
1716                 if (ctx->split && flags != COMMIT_GRAPH_SPLIT_REPLACE &&
1717                     commit_graph_position(ctx->commits.list[ctx->commits.nr]) != COMMIT_NOT_FROM_GRAPH)
1718                         continue;
1719
1720                 if (ctx->split && flags == COMMIT_GRAPH_SPLIT_REPLACE)
1721                         parse_commit(ctx->commits.list[ctx->commits.nr]);
1722                 else
1723                         parse_commit_no_graph(ctx->commits.list[ctx->commits.nr]);
1724
1725                 num_parents = commit_list_count(ctx->commits.list[ctx->commits.nr]->parents);
1726                 if (num_parents > 2)
1727                         ctx->num_extra_edges += num_parents - 1;
1728
1729                 ctx->commits.nr++;
1730         }
1731         stop_progress(&ctx->progress);
1732 }
1733
1734 static int write_graph_chunk_base_1(struct hashfile *f,
1735                                     struct commit_graph *g)
1736 {
1737         int num = 0;
1738
1739         if (!g)
1740                 return 0;
1741
1742         num = write_graph_chunk_base_1(f, g->base_graph);
1743         hashwrite(f, g->oid.hash, the_hash_algo->rawsz);
1744         return num + 1;
1745 }
1746
1747 static int write_graph_chunk_base(struct hashfile *f,
1748                                     void *data)
1749 {
1750         struct write_commit_graph_context *ctx = data;
1751         int num = write_graph_chunk_base_1(f, ctx->new_base_graph);
1752
1753         if (num != ctx->num_commit_graphs_after - 1) {
1754                 error(_("failed to write correct number of base graph ids"));
1755                 return -1;
1756         }
1757
1758         return 0;
1759 }
1760
1761 typedef int (*chunk_write_fn)(struct hashfile *f,
1762                               void *data);
1763
1764 struct chunk_info {
1765         uint32_t id;
1766         uint64_t size;
1767         chunk_write_fn write_fn;
1768 };
1769
1770 static int write_commit_graph_file(struct write_commit_graph_context *ctx)
1771 {
1772         uint32_t i;
1773         int fd;
1774         struct hashfile *f;
1775         struct lock_file lk = LOCK_INIT;
1776         struct chunk_info chunks[MAX_NUM_CHUNKS + 1];
1777         const unsigned hashsz = the_hash_algo->rawsz;
1778         struct strbuf progress_title = STRBUF_INIT;
1779         int num_chunks = 3;
1780         uint64_t chunk_offset;
1781         struct object_id file_hash;
1782
1783         if (ctx->split) {
1784                 struct strbuf tmp_file = STRBUF_INIT;
1785
1786                 strbuf_addf(&tmp_file,
1787                             "%s/info/commit-graphs/tmp_graph_XXXXXX",
1788                             ctx->odb->path);
1789                 ctx->graph_name = strbuf_detach(&tmp_file, NULL);
1790         } else {
1791                 ctx->graph_name = get_commit_graph_filename(ctx->odb);
1792         }
1793
1794         if (safe_create_leading_directories(ctx->graph_name)) {
1795                 UNLEAK(ctx->graph_name);
1796                 error(_("unable to create leading directories of %s"),
1797                         ctx->graph_name);
1798                 return -1;
1799         }
1800
1801         if (ctx->split) {
1802                 char *lock_name = get_commit_graph_chain_filename(ctx->odb);
1803
1804                 hold_lock_file_for_update_mode(&lk, lock_name,
1805                                                LOCK_DIE_ON_ERROR, 0444);
1806
1807                 fd = git_mkstemp_mode(ctx->graph_name, 0444);
1808                 if (fd < 0) {
1809                         error(_("unable to create temporary graph layer"));
1810                         return -1;
1811                 }
1812
1813                 if (adjust_shared_perm(ctx->graph_name)) {
1814                         error(_("unable to adjust shared permissions for '%s'"),
1815                               ctx->graph_name);
1816                         return -1;
1817                 }
1818
1819                 f = hashfd(fd, ctx->graph_name);
1820         } else {
1821                 hold_lock_file_for_update_mode(&lk, ctx->graph_name,
1822                                                LOCK_DIE_ON_ERROR, 0444);
1823                 fd = lk.tempfile->fd;
1824                 f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
1825         }
1826
1827         chunks[0].id = GRAPH_CHUNKID_OIDFANOUT;
1828         chunks[0].size = GRAPH_FANOUT_SIZE;
1829         chunks[0].write_fn = write_graph_chunk_fanout;
1830         chunks[1].id = GRAPH_CHUNKID_OIDLOOKUP;
1831         chunks[1].size = hashsz * ctx->commits.nr;
1832         chunks[1].write_fn = write_graph_chunk_oids;
1833         chunks[2].id = GRAPH_CHUNKID_DATA;
1834         chunks[2].size = (hashsz + 16) * ctx->commits.nr;
1835         chunks[2].write_fn = write_graph_chunk_data;
1836
1837         if (git_env_bool(GIT_TEST_COMMIT_GRAPH_NO_GDAT, 0))
1838                 ctx->write_generation_data = 0;
1839         if (ctx->write_generation_data) {
1840                 chunks[num_chunks].id = GRAPH_CHUNKID_GENERATION_DATA;
1841                 chunks[num_chunks].size = sizeof(uint32_t) * ctx->commits.nr;
1842                 chunks[num_chunks].write_fn = write_graph_chunk_generation_data;
1843                 num_chunks++;
1844         }
1845         if (ctx->num_generation_data_overflows) {
1846                 chunks[num_chunks].id = GRAPH_CHUNKID_GENERATION_DATA_OVERFLOW;
1847                 chunks[num_chunks].size = sizeof(timestamp_t) * ctx->num_generation_data_overflows;
1848                 chunks[num_chunks].write_fn = write_graph_chunk_generation_data_overflow;
1849                 num_chunks++;
1850         }
1851         if (ctx->num_extra_edges) {
1852                 chunks[num_chunks].id = GRAPH_CHUNKID_EXTRAEDGES;
1853                 chunks[num_chunks].size = 4 * ctx->num_extra_edges;
1854                 chunks[num_chunks].write_fn = write_graph_chunk_extra_edges;
1855                 num_chunks++;
1856         }
1857         if (ctx->changed_paths) {
1858                 chunks[num_chunks].id = GRAPH_CHUNKID_BLOOMINDEXES;
1859                 chunks[num_chunks].size = sizeof(uint32_t) * ctx->commits.nr;
1860                 chunks[num_chunks].write_fn = write_graph_chunk_bloom_indexes;
1861                 num_chunks++;
1862                 chunks[num_chunks].id = GRAPH_CHUNKID_BLOOMDATA;
1863                 chunks[num_chunks].size = sizeof(uint32_t) * 3
1864                                           + ctx->total_bloom_filter_data_size;
1865                 chunks[num_chunks].write_fn = write_graph_chunk_bloom_data;
1866                 num_chunks++;
1867         }
1868         if (ctx->num_commit_graphs_after > 1) {
1869                 chunks[num_chunks].id = GRAPH_CHUNKID_BASE;
1870                 chunks[num_chunks].size = hashsz * (ctx->num_commit_graphs_after - 1);
1871                 chunks[num_chunks].write_fn = write_graph_chunk_base;
1872                 num_chunks++;
1873         }
1874
1875         chunks[num_chunks].id = 0;
1876         chunks[num_chunks].size = 0;
1877
1878         hashwrite_be32(f, GRAPH_SIGNATURE);
1879
1880         hashwrite_u8(f, GRAPH_VERSION);
1881         hashwrite_u8(f, oid_version());
1882         hashwrite_u8(f, num_chunks);
1883         hashwrite_u8(f, ctx->num_commit_graphs_after - 1);
1884
1885         chunk_offset = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
1886         for (i = 0; i <= num_chunks; i++) {
1887                 uint32_t chunk_write[3];
1888
1889                 chunk_write[0] = htonl(chunks[i].id);
1890                 chunk_write[1] = htonl(chunk_offset >> 32);
1891                 chunk_write[2] = htonl(chunk_offset & 0xffffffff);
1892                 hashwrite(f, chunk_write, 12);
1893
1894                 chunk_offset += chunks[i].size;
1895         }
1896
1897         if (ctx->report_progress) {
1898                 strbuf_addf(&progress_title,
1899                             Q_("Writing out commit graph in %d pass",
1900                                "Writing out commit graph in %d passes",
1901                                num_chunks),
1902                             num_chunks);
1903                 ctx->progress = start_delayed_progress(
1904                         progress_title.buf,
1905                         num_chunks * ctx->commits.nr);
1906         }
1907
1908         for (i = 0; i < num_chunks; i++) {
1909                 uint64_t start_offset = f->total + f->offset;
1910
1911                 if (chunks[i].write_fn(f, ctx))
1912                         return -1;
1913
1914                 if (f->total + f->offset != start_offset + chunks[i].size)
1915                         BUG("expected to write %"PRId64" bytes to chunk %"PRIx32", but wrote %"PRId64" instead",
1916                             chunks[i].size, chunks[i].id,
1917                             f->total + f->offset - start_offset);
1918         }
1919
1920         stop_progress(&ctx->progress);
1921         strbuf_release(&progress_title);
1922
1923         if (ctx->split && ctx->base_graph_name && ctx->num_commit_graphs_after > 1) {
1924                 char *new_base_hash = xstrdup(oid_to_hex(&ctx->new_base_graph->oid));
1925                 char *new_base_name = get_split_graph_filename(ctx->new_base_graph->odb, new_base_hash);
1926
1927                 free(ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2]);
1928                 free(ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2]);
1929                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2] = new_base_name;
1930                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2] = new_base_hash;
1931         }
1932
1933         close_commit_graph(ctx->r->objects);
1934         finalize_hashfile(f, file_hash.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
1935
1936         if (ctx->split) {
1937                 FILE *chainf = fdopen_lock_file(&lk, "w");
1938                 char *final_graph_name;
1939                 int result;
1940
1941                 close(fd);
1942
1943                 if (!chainf) {
1944                         error(_("unable to open commit-graph chain file"));
1945                         return -1;
1946                 }
1947
1948                 if (ctx->base_graph_name) {
1949                         const char *dest;
1950                         int idx = ctx->num_commit_graphs_after - 1;
1951                         if (ctx->num_commit_graphs_after > 1)
1952                                 idx--;
1953
1954                         dest = ctx->commit_graph_filenames_after[idx];
1955
1956                         if (strcmp(ctx->base_graph_name, dest)) {
1957                                 result = rename(ctx->base_graph_name, dest);
1958
1959                                 if (result) {
1960                                         error(_("failed to rename base commit-graph file"));
1961                                         return -1;
1962                                 }
1963                         }
1964                 } else {
1965                         char *graph_name = get_commit_graph_filename(ctx->odb);
1966                         unlink(graph_name);
1967                 }
1968
1969                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(oid_to_hex(&file_hash));
1970                 final_graph_name = get_split_graph_filename(ctx->odb,
1971                                         ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
1972                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1] = final_graph_name;
1973
1974                 result = rename(ctx->graph_name, final_graph_name);
1975
1976                 for (i = 0; i < ctx->num_commit_graphs_after; i++)
1977                         fprintf(lk.tempfile->fp, "%s\n", ctx->commit_graph_hash_after[i]);
1978
1979                 if (result) {
1980                         error(_("failed to rename temporary commit-graph file"));
1981                         return -1;
1982                 }
1983         }
1984
1985         commit_lock_file(&lk);
1986
1987         return 0;
1988 }
1989
1990 static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
1991 {
1992         struct commit_graph *g;
1993         uint32_t num_commits;
1994         enum commit_graph_split_flags flags = COMMIT_GRAPH_SPLIT_UNSPECIFIED;
1995         uint32_t i;
1996
1997         int max_commits = 0;
1998         int size_mult = 2;
1999
2000         if (ctx->opts) {
2001                 max_commits = ctx->opts->max_commits;
2002
2003                 if (ctx->opts->size_multiple)
2004                         size_mult = ctx->opts->size_multiple;
2005
2006                 flags = ctx->opts->split_flags;
2007         }
2008
2009         g = ctx->r->objects->commit_graph;
2010         num_commits = ctx->commits.nr;
2011         if (flags == COMMIT_GRAPH_SPLIT_REPLACE)
2012                 ctx->num_commit_graphs_after = 1;
2013         else
2014                 ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1;
2015
2016         if (flags != COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED &&
2017             flags != COMMIT_GRAPH_SPLIT_REPLACE) {
2018                 while (g && (g->num_commits <= size_mult * num_commits ||
2019                             (max_commits && num_commits > max_commits))) {
2020                         if (g->odb != ctx->odb)
2021                                 break;
2022
2023                         num_commits += g->num_commits;
2024                         g = g->base_graph;
2025
2026                         ctx->num_commit_graphs_after--;
2027                 }
2028         }
2029
2030         if (flags != COMMIT_GRAPH_SPLIT_REPLACE)
2031                 ctx->new_base_graph = g;
2032         else if (ctx->num_commit_graphs_after != 1)
2033                 BUG("split_graph_merge_strategy: num_commit_graphs_after "
2034                     "should be 1 with --split=replace");
2035
2036         if (ctx->num_commit_graphs_after == 2) {
2037                 char *old_graph_name = get_commit_graph_filename(g->odb);
2038
2039                 if (!strcmp(g->filename, old_graph_name) &&
2040                     g->odb != ctx->odb) {
2041                         ctx->num_commit_graphs_after = 1;
2042                         ctx->new_base_graph = NULL;
2043                 }
2044
2045                 free(old_graph_name);
2046         }
2047
2048         CALLOC_ARRAY(ctx->commit_graph_filenames_after, ctx->num_commit_graphs_after);
2049         CALLOC_ARRAY(ctx->commit_graph_hash_after, ctx->num_commit_graphs_after);
2050
2051         for (i = 0; i < ctx->num_commit_graphs_after &&
2052                     i < ctx->num_commit_graphs_before; i++)
2053                 ctx->commit_graph_filenames_after[i] = xstrdup(ctx->commit_graph_filenames_before[i]);
2054
2055         i = ctx->num_commit_graphs_before - 1;
2056         g = ctx->r->objects->commit_graph;
2057
2058         while (g) {
2059                 if (i < ctx->num_commit_graphs_after)
2060                         ctx->commit_graph_hash_after[i] = xstrdup(oid_to_hex(&g->oid));
2061
2062                 /*
2063                  * If the topmost remaining layer has generation data chunk, the
2064                  * resultant layer also has generation data chunk.
2065                  */
2066                 if (i == ctx->num_commit_graphs_after - 2)
2067                         ctx->write_generation_data = !!g->chunk_generation_data;
2068
2069                 i--;
2070                 g = g->base_graph;
2071         }
2072 }
2073
2074 static void merge_commit_graph(struct write_commit_graph_context *ctx,
2075                                struct commit_graph *g)
2076 {
2077         uint32_t i;
2078         uint32_t offset = g->num_commits_in_base;
2079
2080         ALLOC_GROW(ctx->commits.list, ctx->commits.nr + g->num_commits, ctx->commits.alloc);
2081
2082         for (i = 0; i < g->num_commits; i++) {
2083                 struct object_id oid;
2084                 struct commit *result;
2085
2086                 display_progress(ctx->progress, i + 1);
2087
2088                 load_oid_from_graph(g, i + offset, &oid);
2089
2090                 /* only add commits if they still exist in the repo */
2091                 result = lookup_commit_reference_gently(ctx->r, &oid, 1);
2092
2093                 if (result) {
2094                         ctx->commits.list[ctx->commits.nr] = result;
2095                         ctx->commits.nr++;
2096                 }
2097         }
2098 }
2099
2100 static int commit_compare(const void *_a, const void *_b)
2101 {
2102         const struct commit *a = *(const struct commit **)_a;
2103         const struct commit *b = *(const struct commit **)_b;
2104         return oidcmp(&a->object.oid, &b->object.oid);
2105 }
2106
2107 static void sort_and_scan_merged_commits(struct write_commit_graph_context *ctx)
2108 {
2109         uint32_t i, dedup_i = 0;
2110
2111         if (ctx->report_progress)
2112                 ctx->progress = start_delayed_progress(
2113                                         _("Scanning merged commits"),
2114                                         ctx->commits.nr);
2115
2116         QSORT(ctx->commits.list, ctx->commits.nr, commit_compare);
2117
2118         ctx->num_extra_edges = 0;
2119         for (i = 0; i < ctx->commits.nr; i++) {
2120                 display_progress(ctx->progress, i);
2121
2122                 if (i && oideq(&ctx->commits.list[i - 1]->object.oid,
2123                           &ctx->commits.list[i]->object.oid)) {
2124                         /*
2125                          * Silently ignore duplicates. These were likely
2126                          * created due to a commit appearing in multiple
2127                          * layers of the chain, which is unexpected but
2128                          * not invalid. We should make sure there is a
2129                          * unique copy in the new layer.
2130                          */
2131                 } else {
2132                         unsigned int num_parents;
2133
2134                         ctx->commits.list[dedup_i] = ctx->commits.list[i];
2135                         dedup_i++;
2136
2137                         num_parents = commit_list_count(ctx->commits.list[i]->parents);
2138                         if (num_parents > 2)
2139                                 ctx->num_extra_edges += num_parents - 1;
2140                 }
2141         }
2142
2143         ctx->commits.nr = dedup_i;
2144
2145         stop_progress(&ctx->progress);
2146 }
2147
2148 static void merge_commit_graphs(struct write_commit_graph_context *ctx)
2149 {
2150         struct commit_graph *g = ctx->r->objects->commit_graph;
2151         uint32_t current_graph_number = ctx->num_commit_graphs_before;
2152
2153         while (g && current_graph_number >= ctx->num_commit_graphs_after) {
2154                 current_graph_number--;
2155
2156                 if (ctx->report_progress)
2157                         ctx->progress = start_delayed_progress(_("Merging commit-graph"), 0);
2158
2159                 merge_commit_graph(ctx, g);
2160                 stop_progress(&ctx->progress);
2161
2162                 g = g->base_graph;
2163         }
2164
2165         if (g) {
2166                 ctx->new_base_graph = g;
2167                 ctx->new_num_commits_in_base = g->num_commits + g->num_commits_in_base;
2168         }
2169
2170         if (ctx->new_base_graph)
2171                 ctx->base_graph_name = xstrdup(ctx->new_base_graph->filename);
2172
2173         sort_and_scan_merged_commits(ctx);
2174 }
2175
2176 static void mark_commit_graphs(struct write_commit_graph_context *ctx)
2177 {
2178         uint32_t i;
2179         time_t now = time(NULL);
2180
2181         for (i = ctx->num_commit_graphs_after - 1; i < ctx->num_commit_graphs_before; i++) {
2182                 struct stat st;
2183                 struct utimbuf updated_time;
2184
2185                 stat(ctx->commit_graph_filenames_before[i], &st);
2186
2187                 updated_time.actime = st.st_atime;
2188                 updated_time.modtime = now;
2189                 utime(ctx->commit_graph_filenames_before[i], &updated_time);
2190         }
2191 }
2192
2193 static void expire_commit_graphs(struct write_commit_graph_context *ctx)
2194 {
2195         struct strbuf path = STRBUF_INIT;
2196         DIR *dir;
2197         struct dirent *de;
2198         size_t dirnamelen;
2199         timestamp_t expire_time = time(NULL);
2200
2201         if (ctx->opts && ctx->opts->expire_time)
2202                 expire_time = ctx->opts->expire_time;
2203         if (!ctx->split) {
2204                 char *chain_file_name = get_commit_graph_chain_filename(ctx->odb);
2205                 unlink(chain_file_name);
2206                 free(chain_file_name);
2207                 ctx->num_commit_graphs_after = 0;
2208         }
2209
2210         strbuf_addstr(&path, ctx->odb->path);
2211         strbuf_addstr(&path, "/info/commit-graphs");
2212         dir = opendir(path.buf);
2213
2214         if (!dir)
2215                 goto out;
2216
2217         strbuf_addch(&path, '/');
2218         dirnamelen = path.len;
2219         while ((de = readdir(dir)) != NULL) {
2220                 struct stat st;
2221                 uint32_t i, found = 0;
2222
2223                 strbuf_setlen(&path, dirnamelen);
2224                 strbuf_addstr(&path, de->d_name);
2225
2226                 stat(path.buf, &st);
2227
2228                 if (st.st_mtime > expire_time)
2229                         continue;
2230                 if (path.len < 6 || strcmp(path.buf + path.len - 6, ".graph"))
2231                         continue;
2232
2233                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
2234                         if (!strcmp(ctx->commit_graph_filenames_after[i],
2235                                     path.buf)) {
2236                                 found = 1;
2237                                 break;
2238                         }
2239                 }
2240
2241                 if (!found)
2242                         unlink(path.buf);
2243         }
2244
2245 out:
2246         strbuf_release(&path);
2247 }
2248
2249 int write_commit_graph(struct object_directory *odb,
2250                        struct string_list *pack_indexes,
2251                        struct oidset *commits,
2252                        enum commit_graph_write_flags flags,
2253                        const struct commit_graph_opts *opts)
2254 {
2255         struct write_commit_graph_context *ctx;
2256         uint32_t i;
2257         int res = 0;
2258         int replace = 0;
2259         struct bloom_filter_settings bloom_settings = DEFAULT_BLOOM_FILTER_SETTINGS;
2260         struct topo_level_slab topo_levels;
2261
2262         prepare_repo_settings(the_repository);
2263         if (!the_repository->settings.core_commit_graph) {
2264                 warning(_("attempting to write a commit-graph, but 'core.commitGraph' is disabled"));
2265                 return 0;
2266         }
2267         if (!commit_graph_compatible(the_repository))
2268                 return 0;
2269
2270         ctx = xcalloc(1, sizeof(struct write_commit_graph_context));
2271         ctx->r = the_repository;
2272         ctx->odb = odb;
2273         ctx->append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0;
2274         ctx->report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0;
2275         ctx->split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
2276         ctx->opts = opts;
2277         ctx->total_bloom_filter_data_size = 0;
2278         ctx->write_generation_data = 1;
2279         ctx->num_generation_data_overflows = 0;
2280
2281         bloom_settings.bits_per_entry = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_BITS_PER_ENTRY",
2282                                                       bloom_settings.bits_per_entry);
2283         bloom_settings.num_hashes = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_NUM_HASHES",
2284                                                   bloom_settings.num_hashes);
2285         bloom_settings.max_changed_paths = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_MAX_CHANGED_PATHS",
2286                                                          bloom_settings.max_changed_paths);
2287         ctx->bloom_settings = &bloom_settings;
2288
2289         init_topo_level_slab(&topo_levels);
2290         ctx->topo_levels = &topo_levels;
2291
2292         if (ctx->r->objects->commit_graph) {
2293                 struct commit_graph *g = ctx->r->objects->commit_graph;
2294
2295                 while (g) {
2296                         g->topo_levels = &topo_levels;
2297                         g = g->base_graph;
2298                 }
2299         }
2300
2301         if (flags & COMMIT_GRAPH_WRITE_BLOOM_FILTERS)
2302                 ctx->changed_paths = 1;
2303         if (!(flags & COMMIT_GRAPH_NO_WRITE_BLOOM_FILTERS)) {
2304                 struct commit_graph *g;
2305                 prepare_commit_graph_one(ctx->r, ctx->odb);
2306
2307                 g = ctx->r->objects->commit_graph;
2308
2309                 /* We have changed-paths already. Keep them in the next graph */
2310                 if (g && g->chunk_bloom_data) {
2311                         ctx->changed_paths = 1;
2312                         ctx->bloom_settings = g->bloom_filter_settings;
2313                 }
2314         }
2315
2316         if (ctx->split) {
2317                 struct commit_graph *g;
2318                 prepare_commit_graph(ctx->r);
2319
2320                 g = ctx->r->objects->commit_graph;
2321
2322                 while (g) {
2323                         ctx->num_commit_graphs_before++;
2324                         g = g->base_graph;
2325                 }
2326
2327                 if (ctx->num_commit_graphs_before) {
2328                         ALLOC_ARRAY(ctx->commit_graph_filenames_before, ctx->num_commit_graphs_before);
2329                         i = ctx->num_commit_graphs_before;
2330                         g = ctx->r->objects->commit_graph;
2331
2332                         while (g) {
2333                                 ctx->commit_graph_filenames_before[--i] = xstrdup(g->filename);
2334                                 g = g->base_graph;
2335                         }
2336                 }
2337
2338                 if (ctx->opts)
2339                         replace = ctx->opts->split_flags & COMMIT_GRAPH_SPLIT_REPLACE;
2340         }
2341
2342         ctx->approx_nr_objects = approximate_object_count();
2343
2344         if (ctx->append)
2345                 prepare_commit_graph_one(ctx->r, ctx->odb);
2346
2347         if (ctx->append && ctx->r->objects->commit_graph) {
2348                 struct commit_graph *g = ctx->r->objects->commit_graph;
2349                 for (i = 0; i < g->num_commits; i++) {
2350                         struct object_id oid;
2351                         hashcpy(oid.hash, g->chunk_oid_lookup + g->hash_len * i);
2352                         oid_array_append(&ctx->oids, &oid);
2353                 }
2354         }
2355
2356         if (pack_indexes) {
2357                 ctx->order_by_pack = 1;
2358                 if ((res = fill_oids_from_packs(ctx, pack_indexes)))
2359                         goto cleanup;
2360         }
2361
2362         if (commits) {
2363                 if ((res = fill_oids_from_commits(ctx, commits)))
2364                         goto cleanup;
2365         }
2366
2367         if (!pack_indexes && !commits) {
2368                 ctx->order_by_pack = 1;
2369                 fill_oids_from_all_packs(ctx);
2370         }
2371
2372         close_reachable(ctx);
2373
2374         copy_oids_to_commits(ctx);
2375
2376         if (ctx->commits.nr >= GRAPH_EDGE_LAST_MASK) {
2377                 error(_("too many commits to write graph"));
2378                 res = -1;
2379                 goto cleanup;
2380         }
2381
2382         if (!ctx->commits.nr && !replace)
2383                 goto cleanup;
2384
2385         if (ctx->split) {
2386                 split_graph_merge_strategy(ctx);
2387
2388                 if (!replace)
2389                         merge_commit_graphs(ctx);
2390         } else
2391                 ctx->num_commit_graphs_after = 1;
2392
2393         validate_mixed_generation_chain(ctx->r->objects->commit_graph);
2394
2395         compute_generation_numbers(ctx);
2396
2397         if (ctx->changed_paths)
2398                 compute_bloom_filters(ctx);
2399
2400         res = write_commit_graph_file(ctx);
2401
2402         if (ctx->split)
2403                 mark_commit_graphs(ctx);
2404
2405         expire_commit_graphs(ctx);
2406
2407 cleanup:
2408         free(ctx->graph_name);
2409         free(ctx->commits.list);
2410         oid_array_clear(&ctx->oids);
2411
2412         if (ctx->commit_graph_filenames_after) {
2413                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
2414                         free(ctx->commit_graph_filenames_after[i]);
2415                         free(ctx->commit_graph_hash_after[i]);
2416                 }
2417
2418                 for (i = 0; i < ctx->num_commit_graphs_before; i++)
2419                         free(ctx->commit_graph_filenames_before[i]);
2420
2421                 free(ctx->commit_graph_filenames_after);
2422                 free(ctx->commit_graph_filenames_before);
2423                 free(ctx->commit_graph_hash_after);
2424         }
2425
2426         free(ctx);
2427
2428         return res;
2429 }
2430
2431 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
2432 static int verify_commit_graph_error;
2433
2434 static void graph_report(const char *fmt, ...)
2435 {
2436         va_list ap;
2437
2438         verify_commit_graph_error = 1;
2439         va_start(ap, fmt);
2440         vfprintf(stderr, fmt, ap);
2441         fprintf(stderr, "\n");
2442         va_end(ap);
2443 }
2444
2445 #define GENERATION_ZERO_EXISTS 1
2446 #define GENERATION_NUMBER_EXISTS 2
2447
2448 int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
2449 {
2450         uint32_t i, cur_fanout_pos = 0;
2451         struct object_id prev_oid, cur_oid, checksum;
2452         int generation_zero = 0;
2453         struct hashfile *f;
2454         int devnull;
2455         struct progress *progress = NULL;
2456         int local_error = 0;
2457
2458         if (!g) {
2459                 graph_report("no commit-graph file loaded");
2460                 return 1;
2461         }
2462
2463         verify_commit_graph_error = verify_commit_graph_lite(g);
2464         if (verify_commit_graph_error)
2465                 return verify_commit_graph_error;
2466
2467         devnull = open("/dev/null", O_WRONLY);
2468         f = hashfd(devnull, NULL);
2469         hashwrite(f, g->data, g->data_len - g->hash_len);
2470         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
2471         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
2472                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
2473                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
2474         }
2475
2476         for (i = 0; i < g->num_commits; i++) {
2477                 struct commit *graph_commit;
2478
2479                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
2480
2481                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
2482                         graph_report(_("commit-graph has incorrect OID order: %s then %s"),
2483                                      oid_to_hex(&prev_oid),
2484                                      oid_to_hex(&cur_oid));
2485
2486                 oidcpy(&prev_oid, &cur_oid);
2487
2488                 while (cur_oid.hash[0] > cur_fanout_pos) {
2489                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
2490
2491                         if (i != fanout_value)
2492                                 graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
2493                                              cur_fanout_pos, fanout_value, i);
2494                         cur_fanout_pos++;
2495                 }
2496
2497                 graph_commit = lookup_commit(r, &cur_oid);
2498                 if (!parse_commit_in_graph_one(r, g, graph_commit))
2499                         graph_report(_("failed to parse commit %s from commit-graph"),
2500                                      oid_to_hex(&cur_oid));
2501         }
2502
2503         while (cur_fanout_pos < 256) {
2504                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
2505
2506                 if (g->num_commits != fanout_value)
2507                         graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
2508                                      cur_fanout_pos, fanout_value, i);
2509
2510                 cur_fanout_pos++;
2511         }
2512
2513         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
2514                 return verify_commit_graph_error;
2515
2516         if (flags & COMMIT_GRAPH_WRITE_PROGRESS)
2517                 progress = start_progress(_("Verifying commits in commit graph"),
2518                                         g->num_commits);
2519
2520         for (i = 0; i < g->num_commits; i++) {
2521                 struct commit *graph_commit, *odb_commit;
2522                 struct commit_list *graph_parents, *odb_parents;
2523                 timestamp_t max_generation = 0;
2524                 timestamp_t generation;
2525
2526                 display_progress(progress, i + 1);
2527                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
2528
2529                 graph_commit = lookup_commit(r, &cur_oid);
2530                 odb_commit = (struct commit *)create_object(r, &cur_oid, alloc_commit_node(r));
2531                 if (parse_commit_internal(odb_commit, 0, 0)) {
2532                         graph_report(_("failed to parse commit %s from object database for commit-graph"),
2533                                      oid_to_hex(&cur_oid));
2534                         continue;
2535                 }
2536
2537                 if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
2538                            get_commit_tree_oid(odb_commit)))
2539                         graph_report(_("root tree OID for commit %s in commit-graph is %s != %s"),
2540                                      oid_to_hex(&cur_oid),
2541                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
2542                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
2543
2544                 graph_parents = graph_commit->parents;
2545                 odb_parents = odb_commit->parents;
2546
2547                 while (graph_parents) {
2548                         if (odb_parents == NULL) {
2549                                 graph_report(_("commit-graph parent list for commit %s is too long"),
2550                                              oid_to_hex(&cur_oid));
2551                                 break;
2552                         }
2553
2554                         /* parse parent in case it is in a base graph */
2555                         parse_commit_in_graph_one(r, g, graph_parents->item);
2556
2557                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
2558                                 graph_report(_("commit-graph parent for %s is %s != %s"),
2559                                              oid_to_hex(&cur_oid),
2560                                              oid_to_hex(&graph_parents->item->object.oid),
2561                                              oid_to_hex(&odb_parents->item->object.oid));
2562
2563                         generation = commit_graph_generation(graph_parents->item);
2564                         if (generation > max_generation)
2565                                 max_generation = generation;
2566
2567                         graph_parents = graph_parents->next;
2568                         odb_parents = odb_parents->next;
2569                 }
2570
2571                 if (odb_parents != NULL)
2572                         graph_report(_("commit-graph parent list for commit %s terminates early"),
2573                                      oid_to_hex(&cur_oid));
2574
2575                 if (!commit_graph_generation(graph_commit)) {
2576                         if (generation_zero == GENERATION_NUMBER_EXISTS)
2577                                 graph_report(_("commit-graph has generation number zero for commit %s, but non-zero elsewhere"),
2578                                              oid_to_hex(&cur_oid));
2579                         generation_zero = GENERATION_ZERO_EXISTS;
2580                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
2581                         graph_report(_("commit-graph has non-zero generation number for commit %s, but zero elsewhere"),
2582                                      oid_to_hex(&cur_oid));
2583
2584                 if (generation_zero == GENERATION_ZERO_EXISTS)
2585                         continue;
2586
2587                 /*
2588                  * If we are using topological level and one of our parents has
2589                  * generation GENERATION_NUMBER_V1_MAX, then our generation is
2590                  * also GENERATION_NUMBER_V1_MAX. Decrement to avoid extra logic
2591                  * in the following condition.
2592                  */
2593                 if (!g->read_generation_data && max_generation == GENERATION_NUMBER_V1_MAX)
2594                         max_generation--;
2595
2596                 generation = commit_graph_generation(graph_commit);
2597                 if (generation < max_generation + 1)
2598                         graph_report(_("commit-graph generation for commit %s is %"PRItime" < %"PRItime),
2599                                      oid_to_hex(&cur_oid),
2600                                      generation,
2601                                      max_generation + 1);
2602
2603                 if (graph_commit->date != odb_commit->date)
2604                         graph_report(_("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime),
2605                                      oid_to_hex(&cur_oid),
2606                                      graph_commit->date,
2607                                      odb_commit->date);
2608         }
2609         stop_progress(&progress);
2610
2611         local_error = verify_commit_graph_error;
2612
2613         if (!(flags & COMMIT_GRAPH_VERIFY_SHALLOW) && g->base_graph)
2614                 local_error |= verify_commit_graph(r, g->base_graph, flags);
2615
2616         return local_error;
2617 }
2618
2619 void free_commit_graph(struct commit_graph *g)
2620 {
2621         if (!g)
2622                 return;
2623         if (g->data) {
2624                 munmap((void *)g->data, g->data_len);
2625                 g->data = NULL;
2626         }
2627         free(g->filename);
2628         free(g->bloom_filter_settings);
2629         free(g);
2630 }
2631
2632 void disable_commit_graph(struct repository *r)
2633 {
2634         r->commit_graph_disabled = 1;
2635 }