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

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "dir.h"
   4 #include "git-compat-util.h"
   5 #include "lockfile.h"
   6 #include "pack.h"
   7 #include "packfile.h"
   8 #include "commit.h"
   9 #include "object.h"
  10 #include "refs.h"
  11 #include "revision.h"
  12 #include "sha1-lookup.h"
  13 #include "commit-graph.h"
  14 #include "object-store.h"
  15 #include "alloc.h"
  16 #include "hashmap.h"
  17 #include "replace-object.h"
  18 #include "progress.h"
  19
  20 #define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */
  21 #define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
  22 #define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
  23 #define GRAPH_CHUNKID_DATA 0x43444154 /* "CDAT" */
  24 #define GRAPH_CHUNKID_EXTRAEDGES 0x45444745 /* "EDGE" */
  25
  26 #define GRAPH_DATA_WIDTH (the_hash_algo->rawsz + 16)
  27
  28 #define GRAPH_VERSION_1 0x1
  29 #define GRAPH_VERSION GRAPH_VERSION_1
  30
  31 #define GRAPH_EXTRA_EDGES_NEEDED 0x80000000
  32 #define GRAPH_EDGE_LAST_MASK 0x7fffffff
  33 #define GRAPH_PARENT_NONE 0x70000000
  34
  35 #define GRAPH_LAST_EDGE 0x80000000
  36
  37 #define GRAPH_HEADER_SIZE 8
  38 #define GRAPH_FANOUT_SIZE (4 * 256)
  39 #define GRAPH_CHUNKLOOKUP_WIDTH 12
  40 #define GRAPH_MIN_SIZE (GRAPH_HEADER_SIZE + 4 * GRAPH_CHUNKLOOKUP_WIDTH \
  41                         + GRAPH_FANOUT_SIZE + the_hash_algo->rawsz)
  42
  43 char *get_commit_graph_filename(const char *obj_dir)
  44 {
  45         return xstrfmt("%s/info/commit-graph", obj_dir);
  46 }
  47
  48 static uint8_t oid_version(void)
  49 {
  50         return 1;
  51 }
  52
  53 static struct commit_graph *alloc_commit_graph(void)
  54 {
  55         struct commit_graph *g = xcalloc(1, sizeof(*g));
  56         g->graph_fd = -1;
  57
  58         return g;
  59 }
  60
  61 extern int read_replace_refs;
  62
  63 static int commit_graph_compatible(struct repository *r)
  64 {
  65         if (!r->gitdir)
  66                 return 0;
  67
  68         if (read_replace_refs) {
  69                 prepare_replace_object(r);
  70                 if (hashmap_get_size(&r->objects->replace_map->map))
  71                         return 0;
  72         }
  73
  74         prepare_commit_graft(r);
  75         if (r->parsed_objects && r->parsed_objects->grafts_nr)
  76                 return 0;
  77         if (is_repository_shallow(r))
  78                 return 0;
  79
  80         return 1;
  81 }
  82
  83 int open_commit_graph(const char *graph_file, int *fd, struct stat *st)
  84 {
  85         *fd = git_open(graph_file);
  86         if (*fd < 0)
  87                 return 0;
  88         if (fstat(*fd, st)) {
  89                 close(*fd);
  90                 return 0;
  91         }
  92         return 1;
  93 }
  94
  95 struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st)
  96 {
  97         void *graph_map;
  98         size_t graph_size;
  99         struct commit_graph *ret;
 100
 101         graph_size = xsize_t(st->st_size);
 102
 103         if (graph_size < GRAPH_MIN_SIZE) {
 104                 close(fd);
 105                 error(_("commit-graph file is too small"));
 106                 return NULL;
 107         }
 108         graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
 109         ret = parse_commit_graph(graph_map, fd, graph_size);
 110
 111         if (!ret) {
 112                 munmap(graph_map, graph_size);
 113                 close(fd);
 114         }
 115
 116         return ret;
 117 }
 118
 119 static int verify_commit_graph_lite(struct commit_graph *g)
 120 {
 121         /*
 122          * Basic validation shared between parse_commit_graph()
 123          * which'll be called every time the graph is used, and the
 124          * much more expensive verify_commit_graph() used by
 125          * "commit-graph verify".
 126          *
 127          * There should only be very basic checks here to ensure that
 128          * we don't e.g. segfault in fill_commit_in_graph(), but
 129          * because this is a very hot codepath nothing that e.g. loops
 130          * over g->num_commits, or runs a checksum on the commit-graph
 131          * itself.
 132          */
 133         if (!g->chunk_oid_fanout) {
 134                 error("commit-graph is missing the OID Fanout chunk");
 135                 return 1;
 136         }
 137         if (!g->chunk_oid_lookup) {
 138                 error("commit-graph is missing the OID Lookup chunk");
 139                 return 1;
 140         }
 141         if (!g->chunk_commit_data) {
 142                 error("commit-graph is missing the Commit Data chunk");
 143                 return 1;
 144         }
 145
 146         return 0;
 147 }
 148
 149 struct commit_graph *parse_commit_graph(void *graph_map, int fd,
 150                                         size_t graph_size)
 151 {
 152         const unsigned char *data, *chunk_lookup;
 153         uint32_t i;
 154         struct commit_graph *graph;
 155         uint64_t last_chunk_offset;
 156         uint32_t last_chunk_id;
 157         uint32_t graph_signature;
 158         unsigned char graph_version, hash_version;
 159
 160         if (!graph_map)
 161                 return NULL;
 162
 163         if (graph_size < GRAPH_MIN_SIZE)
 164                 return NULL;
 165
 166         data = (const unsigned char *)graph_map;
 167
 168         graph_signature = get_be32(data);
 169         if (graph_signature != GRAPH_SIGNATURE) {
 170                 error(_("commit-graph signature %X does not match signature %X"),
 171                       graph_signature, GRAPH_SIGNATURE);
 172                 return NULL;
 173         }
 174
 175         graph_version = *(unsigned char*)(data + 4);
 176         if (graph_version != GRAPH_VERSION) {
 177                 error(_("commit-graph version %X does not match version %X"),
 178                       graph_version, GRAPH_VERSION);
 179                 return NULL;
 180         }
 181
 182         hash_version = *(unsigned char*)(data + 5);
 183         if (hash_version != oid_version()) {
 184                 error(_("commit-graph hash version %X does not match version %X"),
 185                       hash_version, oid_version());
 186                 return NULL;
 187         }
 188
 189         graph = alloc_commit_graph();
 190
 191         graph->hash_len = the_hash_algo->rawsz;
 192         graph->num_chunks = *(unsigned char*)(data + 6);
 193         graph->graph_fd = fd;
 194         graph->data = graph_map;
 195         graph->data_len = graph_size;
 196
 197         last_chunk_id = 0;
 198         last_chunk_offset = 8;
 199         chunk_lookup = data + 8;
 200         for (i = 0; i < graph->num_chunks; i++) {
 201                 uint32_t chunk_id;
 202                 uint64_t chunk_offset;
 203                 int chunk_repeated = 0;
 204
 205                 if (data + graph_size - chunk_lookup <
 206                     GRAPH_CHUNKLOOKUP_WIDTH) {
 207                         error(_("commit-graph chunk lookup table entry missing; file may be incomplete"));
 208                         free(graph);
 209                         return NULL;
 210                 }
 211
 212                 chunk_id = get_be32(chunk_lookup + 0);
 213                 chunk_offset = get_be64(chunk_lookup + 4);
 214
 215                 chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
 216
 217                 if (chunk_offset > graph_size - the_hash_algo->rawsz) {
 218                         error(_("commit-graph improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
 219                               (uint32_t)chunk_offset);
 220                         free(graph);
 221                         return NULL;
 222                 }
 223
 224                 switch (chunk_id) {
 225                 case GRAPH_CHUNKID_OIDFANOUT:
 226                         if (graph->chunk_oid_fanout)
 227                                 chunk_repeated = 1;
 228                         else
 229                                 graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
 230                         break;
 231
 232                 case GRAPH_CHUNKID_OIDLOOKUP:
 233                         if (graph->chunk_oid_lookup)
 234                                 chunk_repeated = 1;
 235                         else
 236                                 graph->chunk_oid_lookup = data + chunk_offset;
 237                         break;
 238
 239                 case GRAPH_CHUNKID_DATA:
 240                         if (graph->chunk_commit_data)
 241                                 chunk_repeated = 1;
 242                         else
 243                                 graph->chunk_commit_data = data + chunk_offset;
 244                         break;
 245
 246                 case GRAPH_CHUNKID_EXTRAEDGES:
 247                         if (graph->chunk_extra_edges)
 248                                 chunk_repeated = 1;
 249                         else
 250                                 graph->chunk_extra_edges = data + chunk_offset;
 251                         break;
 252                 }
 253
 254                 if (chunk_repeated) {
 255                         error(_("commit-graph chunk id %08x appears multiple times"), chunk_id);
 256                         free(graph);
 257                         return NULL;
 258                 }
 259
 260                 if (last_chunk_id == GRAPH_CHUNKID_OIDLOOKUP)
 261                 {
 262                         graph->num_commits = (chunk_offset - last_chunk_offset)
 263                                              / graph->hash_len;
 264                 }
 265
 266                 last_chunk_id = chunk_id;
 267                 last_chunk_offset = chunk_offset;
 268         }
 269
 270         if (verify_commit_graph_lite(graph))
 271                 return NULL;
 272
 273         return graph;
 274 }
 275
 276 static struct commit_graph *load_commit_graph_one(const char *graph_file)
 277 {
 278
 279         struct stat st;
 280         int fd;
 281         int open_ok = open_commit_graph(graph_file, &fd, &st);
 282
 283         if (!open_ok)
 284                 return NULL;
 285
 286         return load_commit_graph_one_fd_st(fd, &st);
 287 }
 288
 289 static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
 290 {
 291         char *graph_name;
 292
 293         if (r->objects->commit_graph)
 294                 return;
 295
 296         graph_name = get_commit_graph_filename(obj_dir);
 297         r->objects->commit_graph =
 298                 load_commit_graph_one(graph_name);
 299
 300         FREE_AND_NULL(graph_name);
 301 }
 302
 303 /*
 304  * Return 1 if commit_graph is non-NULL, and 0 otherwise.
 305  *
 306  * On the first invocation, this function attemps to load the commit
 307  * graph if the_repository is configured to have one.
 308  */
 309 static int prepare_commit_graph(struct repository *r)
 310 {
 311         struct object_directory *odb;
 312         int config_value;
 313
 314         if (git_env_bool(GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD, 0))
 315                 die("dying as requested by the '%s' variable on commit-graph load!",
 316                     GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD);
 317
 318         if (r->objects->commit_graph_attempted)
 319                 return !!r->objects->commit_graph;
 320         r->objects->commit_graph_attempted = 1;
 321
 322         if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
 323             (repo_config_get_bool(r, "core.commitgraph", &config_value) ||
 324             !config_value))
 325                 /*
 326                  * This repository is not configured to use commit graphs, so
 327                  * do not load one. (But report commit_graph_attempted anyway
 328                  * so that commit graph loading is not attempted again for this
 329                  * repository.)
 330                  */
 331                 return 0;
 332
 333         if (!commit_graph_compatible(r))
 334                 return 0;
 335
 336         prepare_alt_odb(r);
 337         for (odb = r->objects->odb;
 338              !r->objects->commit_graph && odb;
 339              odb = odb->next)
 340                 prepare_commit_graph_one(r, odb->path);
 341         return !!r->objects->commit_graph;
 342 }
 343
 344 int generation_numbers_enabled(struct repository *r)
 345 {
 346         uint32_t first_generation;
 347         struct commit_graph *g;
 348         if (!prepare_commit_graph(r))
 349                return 0;
 350
 351         g = r->objects->commit_graph;
 352
 353         if (!g->num_commits)
 354                 return 0;
 355
 356         first_generation = get_be32(g->chunk_commit_data +
 357                                     g->hash_len + 8) >> 2;
 358
 359         return !!first_generation;
 360 }
 361
 362 static void close_commit_graph_one(struct commit_graph *g)
 363 {
 364         if (!g)
 365                 return;
 366
 367         close_commit_graph_one(g->base_graph);
 368         free_commit_graph(g);
 369 }
 370
 371 void close_commit_graph(struct raw_object_store *o)
 372 {
 373         close_commit_graph_one(o->commit_graph);
 374         o->commit_graph = NULL;
 375 }
 376
 377 static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
 378 {
 379         return bsearch_hash(oid->hash, g->chunk_oid_fanout,
 380                             g->chunk_oid_lookup, g->hash_len, pos);
 381 }
 382
 383 static void load_oid_from_graph(struct commit_graph *g,
 384                                 uint32_t pos,
 385                                 struct object_id *oid)
 386 {
 387         uint32_t lex_index;
 388
 389         while (g && pos < g->num_commits_in_base)
 390                 g = g->base_graph;
 391
 392         if (!g)
 393                 BUG("NULL commit-graph");
 394
 395         if (pos >= g->num_commits + g->num_commits_in_base)
 396                 die(_("invalid commit position. commit-graph is likely corrupt"));
 397
 398         lex_index = pos - g->num_commits_in_base;
 399
 400         hashcpy(oid->hash, g->chunk_oid_lookup + g->hash_len * lex_index);
 401 }
 402
 403 static struct commit_list **insert_parent_or_die(struct repository *r,
 404                                                  struct commit_graph *g,
 405                                                  uint32_t pos,
 406                                                  struct commit_list **pptr)
 407 {
 408         struct commit *c;
 409         struct object_id oid;
 410
 411         if (pos >= g->num_commits + g->num_commits_in_base)
 412                 die("invalid parent position %"PRIu32, pos);
 413
 414         load_oid_from_graph(g, pos, &oid);
 415         c = lookup_commit(r, &oid);
 416         if (!c)
 417                 die(_("could not find commit %s"), oid_to_hex(&oid));
 418         c->graph_pos = pos;
 419         return &commit_list_insert(c, pptr)->next;
 420 }
 421
 422 static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
 423 {
 424         const unsigned char *commit_data;
 425         uint32_t lex_index;
 426
 427         while (pos < g->num_commits_in_base)
 428                 g = g->base_graph;
 429
 430         lex_index = pos - g->num_commits_in_base;
 431         commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * lex_index;
 432         item->graph_pos = pos;
 433         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 434 }
 435
 436 static int fill_commit_in_graph(struct repository *r,
 437                                 struct commit *item,
 438                                 struct commit_graph *g, uint32_t pos)
 439 {
 440         uint32_t edge_value;
 441         uint32_t *parent_data_ptr;
 442         uint64_t date_low, date_high;
 443         struct commit_list **pptr;
 444         const unsigned char *commit_data;
 445         uint32_t lex_index;
 446
 447         while (pos < g->num_commits_in_base)
 448                 g = g->base_graph;
 449
 450         if (pos >= g->num_commits + g->num_commits_in_base)
 451                 die(_("invalid commit position. commit-graph is likely corrupt"));
 452
 453         /*
 454          * Store the "full" position, but then use the
 455          * "local" position for the rest of the calculation.
 456          */
 457         item->graph_pos = pos;
 458         lex_index = pos - g->num_commits_in_base;
 459
 460         commit_data = g->chunk_commit_data + (g->hash_len + 16) * lex_index;
 461
 462         item->object.parsed = 1;
 463
 464         item->maybe_tree = NULL;
 465
 466         date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
 467         date_low = get_be32(commit_data + g->hash_len + 12);
 468         item->date = (timestamp_t)((date_high << 32) | date_low);
 469
 470         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 471
 472         pptr = &item->parents;
 473
 474         edge_value = get_be32(commit_data + g->hash_len);
 475         if (edge_value == GRAPH_PARENT_NONE)
 476                 return 1;
 477         pptr = insert_parent_or_die(r, g, edge_value, pptr);
 478
 479         edge_value = get_be32(commit_data + g->hash_len + 4);
 480         if (edge_value == GRAPH_PARENT_NONE)
 481                 return 1;
 482         if (!(edge_value & GRAPH_EXTRA_EDGES_NEEDED)) {
 483                 pptr = insert_parent_or_die(r, g, edge_value, pptr);
 484                 return 1;
 485         }
 486
 487         parent_data_ptr = (uint32_t*)(g->chunk_extra_edges +
 488                           4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
 489         do {
 490                 edge_value = get_be32(parent_data_ptr);
 491                 pptr = insert_parent_or_die(r, g,
 492                                             edge_value & GRAPH_EDGE_LAST_MASK,
 493                                             pptr);
 494                 parent_data_ptr++;
 495         } while (!(edge_value & GRAPH_LAST_EDGE));
 496
 497         return 1;
 498 }
 499
 500 static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 501 {
 502         if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
 503                 *pos = item->graph_pos;
 504                 return 1;
 505         } else {
 506                 struct commit_graph *cur_g = g;
 507                 uint32_t lex_index;
 508
 509                 while (cur_g && !bsearch_graph(cur_g, &(item->object.oid), &lex_index))
 510                         cur_g = cur_g->base_graph;
 511
 512                 if (cur_g) {
 513                         *pos = lex_index + cur_g->num_commits_in_base;
 514                         return 1;
 515                 }
 516
 517                 return 0;
 518         }
 519 }
 520
 521 static int parse_commit_in_graph_one(struct repository *r,
 522                                      struct commit_graph *g,
 523                                      struct commit *item)
 524 {
 525         uint32_t pos;
 526
 527         if (item->object.parsed)
 528                 return 1;
 529
 530         if (find_commit_in_graph(item, g, &pos))
 531                 return fill_commit_in_graph(r, item, g, pos);
 532
 533         return 0;
 534 }
 535
 536 int parse_commit_in_graph(struct repository *r, struct commit *item)
 537 {
 538         if (!prepare_commit_graph(r))
 539                 return 0;
 540         return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
 541 }
 542
 543 void load_commit_graph_info(struct repository *r, struct commit *item)
 544 {
 545         uint32_t pos;
 546         if (!prepare_commit_graph(r))
 547                 return;
 548         if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
 549                 fill_commit_graph_info(item, r->objects->commit_graph, pos);
 550 }
 551
 552 static struct tree *load_tree_for_commit(struct repository *r,
 553                                          struct commit_graph *g,
 554                                          struct commit *c)
 555 {
 556         struct object_id oid;
 557         const unsigned char *commit_data;
 558
 559         while (c->graph_pos < g->num_commits_in_base)
 560                 g = g->base_graph;
 561
 562         commit_data = g->chunk_commit_data +
 563                         GRAPH_DATA_WIDTH * (c->graph_pos - g->num_commits_in_base);
 564
 565         hashcpy(oid.hash, commit_data);
 566         c->maybe_tree = lookup_tree(r, &oid);
 567
 568         return c->maybe_tree;
 569 }
 570
 571 static struct tree *get_commit_tree_in_graph_one(struct repository *r,
 572                                                  struct commit_graph *g,
 573                                                  const struct commit *c)
 574 {
 575         if (c->maybe_tree)
 576                 return c->maybe_tree;
 577         if (c->graph_pos == COMMIT_NOT_FROM_GRAPH)
 578                 BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
 579
 580         return load_tree_for_commit(r, g, (struct commit *)c);
 581 }
 582
 583 struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
 584 {
 585         return get_commit_tree_in_graph_one(r, r->objects->commit_graph, c);
 586 }
 587
 588 struct packed_commit_list {
 589         struct commit **list;
 590         int nr;
 591         int alloc;
 592 };
 593
 594 struct packed_oid_list {
 595         struct object_id *list;
 596         int nr;
 597         int alloc;
 598 };
 599
 600 struct write_commit_graph_context {
 601         struct repository *r;
 602         const char *obj_dir;
 603         char *graph_name;
 604         struct packed_oid_list oids;
 605         struct packed_commit_list commits;
 606         int num_extra_edges;
 607         unsigned long approx_nr_objects;
 608         struct progress *progress;
 609         int progress_done;
 610         uint64_t progress_cnt;
 611         unsigned append:1,
 612                  report_progress:1;
 613 };
 614
 615 static void write_graph_chunk_fanout(struct hashfile *f,
 616                                      struct write_commit_graph_context *ctx)
 617 {
 618         int i, count = 0;
 619         struct commit **list = ctx->commits.list;
 620
 621         /*
 622          * Write the first-level table (the list is sorted,
 623          * but we use a 256-entry lookup to be able to avoid
 624          * having to do eight extra binary search iterations).
 625          */
 626         for (i = 0; i < 256; i++) {
 627                 while (count < ctx->commits.nr) {
 628                         if ((*list)->object.oid.hash[0] != i)
 629                                 break;
 630                         display_progress(ctx->progress, ++ctx->progress_cnt);
 631                         count++;
 632                         list++;
 633                 }
 634
 635                 hashwrite_be32(f, count);
 636         }
 637 }
 638
 639 static void write_graph_chunk_oids(struct hashfile *f, int hash_len,
 640                                    struct write_commit_graph_context *ctx)
 641 {
 642         struct commit **list = ctx->commits.list;
 643         int count;
 644         for (count = 0; count < ctx->commits.nr; count++, list++) {
 645                 display_progress(ctx->progress, ++ctx->progress_cnt);
 646                 hashwrite(f, (*list)->object.oid.hash, (int)hash_len);
 647         }
 648 }
 649
 650 static const unsigned char *commit_to_sha1(size_t index, void *table)
 651 {
 652         struct commit **commits = table;
 653         return commits[index]->object.oid.hash;
 654 }
 655
 656 static void write_graph_chunk_data(struct hashfile *f, int hash_len,
 657                                    struct write_commit_graph_context *ctx)
 658 {
 659         struct commit **list = ctx->commits.list;
 660         struct commit **last = ctx->commits.list + ctx->commits.nr;
 661         uint32_t num_extra_edges = 0;
 662
 663         while (list < last) {
 664                 struct commit_list *parent;
 665                 int edge_value;
 666                 uint32_t packedDate[2];
 667                 display_progress(ctx->progress, ++ctx->progress_cnt);
 668
 669                 parse_commit_no_graph(*list);
 670                 hashwrite(f, get_commit_tree_oid(*list)->hash, hash_len);
 671
 672                 parent = (*list)->parents;
 673
 674                 if (!parent)
 675                         edge_value = GRAPH_PARENT_NONE;
 676                 else {
 677                         edge_value = sha1_pos(parent->item->object.oid.hash,
 678                                               ctx->commits.list,
 679                                               ctx->commits.nr,
 680                                               commit_to_sha1);
 681
 682                         if (edge_value < 0)
 683                                 BUG("missing parent %s for commit %s",
 684                                     oid_to_hex(&parent->item->object.oid),
 685                                     oid_to_hex(&(*list)->object.oid));
 686                 }
 687
 688                 hashwrite_be32(f, edge_value);
 689
 690                 if (parent)
 691                         parent = parent->next;
 692
 693                 if (!parent)
 694                         edge_value = GRAPH_PARENT_NONE;
 695                 else if (parent->next)
 696                         edge_value = GRAPH_EXTRA_EDGES_NEEDED | num_extra_edges;
 697                 else {
 698                         edge_value = sha1_pos(parent->item->object.oid.hash,
 699                                               ctx->commits.list,
 700                                               ctx->commits.nr,
 701                                               commit_to_sha1);
 702                         if (edge_value < 0)
 703                                 BUG("missing parent %s for commit %s",
 704                                     oid_to_hex(&parent->item->object.oid),
 705                                     oid_to_hex(&(*list)->object.oid));
 706                 }
 707
 708                 hashwrite_be32(f, edge_value);
 709
 710                 if (edge_value & GRAPH_EXTRA_EDGES_NEEDED) {
 711                         do {
 712                                 num_extra_edges++;
 713                                 parent = parent->next;
 714                         } while (parent);
 715                 }
 716
 717                 if (sizeof((*list)->date) > 4)
 718                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
 719                 else
 720                         packedDate[0] = 0;
 721
 722                 packedDate[0] |= htonl((*list)->generation << 2);
 723
 724                 packedDate[1] = htonl((*list)->date);
 725                 hashwrite(f, packedDate, 8);
 726
 727                 list++;
 728         }
 729 }
 730
 731 static void write_graph_chunk_extra_edges(struct hashfile *f,
 732                                           struct write_commit_graph_context *ctx)
 733 {
 734         struct commit **list = ctx->commits.list;
 735         struct commit **last = ctx->commits.list + ctx->commits.nr;
 736         struct commit_list *parent;
 737
 738         while (list < last) {
 739                 int num_parents = 0;
 740
 741                 display_progress(ctx->progress, ++ctx->progress_cnt);
 742
 743                 for (parent = (*list)->parents; num_parents < 3 && parent;
 744                      parent = parent->next)
 745                         num_parents++;
 746
 747                 if (num_parents <= 2) {
 748                         list++;
 749                         continue;
 750                 }
 751
 752                 /* Since num_parents > 2, this initializer is safe. */
 753                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
 754                         int edge_value = sha1_pos(parent->item->object.oid.hash,
 755                                                   ctx->commits.list,
 756                                                   ctx->commits.nr,
 757                                                   commit_to_sha1);
 758
 759                         if (edge_value < 0)
 760                                 BUG("missing parent %s for commit %s",
 761                                     oid_to_hex(&parent->item->object.oid),
 762                                     oid_to_hex(&(*list)->object.oid));
 763                         else if (!parent->next)
 764                                 edge_value |= GRAPH_LAST_EDGE;
 765
 766                         hashwrite_be32(f, edge_value);
 767                 }
 768
 769                 list++;
 770         }
 771 }
 772
 773 static int oid_compare(const void *_a, const void *_b)
 774 {
 775         const struct object_id *a = (const struct object_id *)_a;
 776         const struct object_id *b = (const struct object_id *)_b;
 777         return oidcmp(a, b);
 778 }
 779
 780 static int add_packed_commits(const struct object_id *oid,
 781                               struct packed_git *pack,
 782                               uint32_t pos,
 783                               void *data)
 784 {
 785         struct write_commit_graph_context *ctx = (struct write_commit_graph_context*)data;
 786         enum object_type type;
 787         off_t offset = nth_packed_object_offset(pack, pos);
 788         struct object_info oi = OBJECT_INFO_INIT;
 789
 790         if (ctx->progress)
 791                 display_progress(ctx->progress, ++ctx->progress_done);
 792
 793         oi.typep = &type;
 794         if (packed_object_info(ctx->r, pack, offset, &oi) < 0)
 795                 die(_("unable to get type of object %s"), oid_to_hex(oid));
 796
 797         if (type != OBJ_COMMIT)
 798                 return 0;
 799
 800         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
 801         oidcpy(&(ctx->oids.list[ctx->oids.nr]), oid);
 802         ctx->oids.nr++;
 803
 804         return 0;
 805 }
 806
 807 static void add_missing_parents(struct write_commit_graph_context *ctx, struct commit *commit)
 808 {
 809         struct commit_list *parent;
 810         for (parent = commit->parents; parent; parent = parent->next) {
 811                 if (!(parent->item->object.flags & UNINTERESTING)) {
 812                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
 813                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(parent->item->object.oid));
 814                         ctx->oids.nr++;
 815                         parent->item->object.flags |= UNINTERESTING;
 816                 }
 817         }
 818 }
 819
 820 static void close_reachable(struct write_commit_graph_context *ctx)
 821 {
 822         int i;
 823         struct commit *commit;
 824
 825         if (ctx->report_progress)
 826                 ctx->progress = start_delayed_progress(
 827                                         _("Loading known commits in commit graph"),
 828                                         ctx->oids.nr);
 829         for (i = 0; i < ctx->oids.nr; i++) {
 830                 display_progress(ctx->progress, i + 1);
 831                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
 832                 if (commit)
 833                         commit->object.flags |= UNINTERESTING;
 834         }
 835         stop_progress(&ctx->progress);
 836
 837         /*
 838          * As this loop runs, ctx->oids.nr may grow, but not more
 839          * than the number of missing commits in the reachable
 840          * closure.
 841          */
 842         if (ctx->report_progress)
 843                 ctx->progress = start_delayed_progress(
 844                                         _("Expanding reachable commits in commit graph"),
 845                                         ctx->oids.nr);
 846         for (i = 0; i < ctx->oids.nr; i++) {
 847                 display_progress(ctx->progress, i + 1);
 848                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
 849
 850                 if (commit && !parse_commit_no_graph(commit))
 851                         add_missing_parents(ctx, commit);
 852         }
 853         stop_progress(&ctx->progress);
 854
 855         if (ctx->report_progress)
 856                 ctx->progress = start_delayed_progress(
 857                                         _("Clearing commit marks in commit graph"),
 858                                         ctx->oids.nr);
 859         for (i = 0; i < ctx->oids.nr; i++) {
 860                 display_progress(ctx->progress, i + 1);
 861                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
 862
 863                 if (commit)
 864                         commit->object.flags &= ~UNINTERESTING;
 865         }
 866         stop_progress(&ctx->progress);
 867 }
 868
 869 static void compute_generation_numbers(struct write_commit_graph_context *ctx)
 870 {
 871         int i;
 872         struct commit_list *list = NULL;
 873
 874         if (ctx->report_progress)
 875                 ctx->progress = start_progress(
 876                                         _("Computing commit graph generation numbers"),
 877                                         ctx->commits.nr);
 878         for (i = 0; i < ctx->commits.nr; i++) {
 879                 display_progress(ctx->progress, i + 1);
 880                 if (ctx->commits.list[i]->generation != GENERATION_NUMBER_INFINITY &&
 881                     ctx->commits.list[i]->generation != GENERATION_NUMBER_ZERO)
 882                         continue;
 883
 884                 commit_list_insert(ctx->commits.list[i], &list);
 885                 while (list) {
 886                         struct commit *current = list->item;
 887                         struct commit_list *parent;
 888                         int all_parents_computed = 1;
 889                         uint32_t max_generation = 0;
 890
 891                         for (parent = current->parents; parent; parent = parent->next) {
 892                                 if (parent->item->generation == GENERATION_NUMBER_INFINITY ||
 893                                     parent->item->generation == GENERATION_NUMBER_ZERO) {
 894                                         all_parents_computed = 0;
 895                                         commit_list_insert(parent->item, &list);
 896                                         break;
 897                                 } else if (parent->item->generation > max_generation) {
 898                                         max_generation = parent->item->generation;
 899                                 }
 900                         }
 901
 902                         if (all_parents_computed) {
 903                                 current->generation = max_generation + 1;
 904                                 pop_commit(&list);
 905
 906                                 if (current->generation > GENERATION_NUMBER_MAX)
 907                                         current->generation = GENERATION_NUMBER_MAX;
 908                         }
 909                 }
 910         }
 911         stop_progress(&ctx->progress);
 912 }
 913
 914 static int add_ref_to_list(const char *refname,
 915                            const struct object_id *oid,
 916                            int flags, void *cb_data)
 917 {
 918         struct string_list *list = (struct string_list *)cb_data;
 919
 920         string_list_append(list, oid_to_hex(oid));
 921         return 0;
 922 }
 923
 924 int write_commit_graph_reachable(const char *obj_dir, unsigned int flags)
 925 {
 926         struct string_list list = STRING_LIST_INIT_DUP;
 927         int result;
 928
 929         for_each_ref(add_ref_to_list, &list);
 930         result = write_commit_graph(obj_dir, NULL, &list,
 931                                     flags);
 932
 933         string_list_clear(&list, 0);
 934         return result;
 935 }
 936
 937 static int fill_oids_from_packs(struct write_commit_graph_context *ctx,
 938                                 struct string_list *pack_indexes)
 939 {
 940         uint32_t i;
 941         struct strbuf progress_title = STRBUF_INIT;
 942         struct strbuf packname = STRBUF_INIT;
 943         int dirlen;
 944
 945         strbuf_addf(&packname, "%s/pack/", ctx->obj_dir);
 946         dirlen = packname.len;
 947         if (ctx->report_progress) {
 948                 strbuf_addf(&progress_title,
 949                             Q_("Finding commits for commit graph in %d pack",
 950                                "Finding commits for commit graph in %d packs",
 951                                pack_indexes->nr),
 952                             pack_indexes->nr);
 953                 ctx->progress = start_delayed_progress(progress_title.buf, 0);
 954                 ctx->progress_done = 0;
 955         }
 956         for (i = 0; i < pack_indexes->nr; i++) {
 957                 struct packed_git *p;
 958                 strbuf_setlen(&packname, dirlen);
 959                 strbuf_addstr(&packname, pack_indexes->items[i].string);
 960                 p = add_packed_git(packname.buf, packname.len, 1);
 961                 if (!p) {
 962                         error(_("error adding pack %s"), packname.buf);
 963                         return -1;
 964                 }
 965                 if (open_pack_index(p)) {
 966                         error(_("error opening index for %s"), packname.buf);
 967                         return -1;
 968                 }
 969                 for_each_object_in_pack(p, add_packed_commits, ctx,
 970                                         FOR_EACH_OBJECT_PACK_ORDER);
 971                 close_pack(p);
 972                 free(p);
 973         }
 974
 975         stop_progress(&ctx->progress);
 976         strbuf_reset(&progress_title);
 977         strbuf_release(&packname);
 978
 979         return 0;
 980 }
 981
 982 static void fill_oids_from_commit_hex(struct write_commit_graph_context *ctx,
 983                                       struct string_list *commit_hex)
 984 {
 985         uint32_t i;
 986         struct strbuf progress_title = STRBUF_INIT;
 987
 988         if (ctx->report_progress) {
 989                 strbuf_addf(&progress_title,
 990                             Q_("Finding commits for commit graph from %d ref",
 991                                "Finding commits for commit graph from %d refs",
 992                                commit_hex->nr),
 993                             commit_hex->nr);
 994                 ctx->progress = start_delayed_progress(
 995                                         progress_title.buf,
 996                                         commit_hex->nr);
 997         }
 998         for (i = 0; i < commit_hex->nr; i++) {
 999                 const char *end;
1000                 struct object_id oid;
1001                 struct commit *result;
1002
1003                 display_progress(ctx->progress, i + 1);
1004                 if (commit_hex->items[i].string &&
1005                     parse_oid_hex(commit_hex->items[i].string, &oid, &end))
1006                         continue;
1007
1008                 result = lookup_commit_reference_gently(ctx->r, &oid, 1);
1009
1010                 if (result) {
1011                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1012                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(result->object.oid));
1013                         ctx->oids.nr++;
1014                 }
1015         }
1016         stop_progress(&ctx->progress);
1017         strbuf_release(&progress_title);
1018 }
1019
1020 static void fill_oids_from_all_packs(struct write_commit_graph_context *ctx)
1021 {
1022         if (ctx->report_progress)
1023                 ctx->progress = start_delayed_progress(
1024                         _("Finding commits for commit graph among packed objects"),
1025                         ctx->approx_nr_objects);
1026         for_each_packed_object(add_packed_commits, ctx,
1027                                FOR_EACH_OBJECT_PACK_ORDER);
1028         if (ctx->progress_done < ctx->approx_nr_objects)
1029                 display_progress(ctx->progress, ctx->approx_nr_objects);
1030         stop_progress(&ctx->progress);
1031 }
1032
1033 static uint32_t count_distinct_commits(struct write_commit_graph_context *ctx)
1034 {
1035         uint32_t i, count_distinct = 1;
1036
1037         if (ctx->report_progress)
1038                 ctx->progress = start_delayed_progress(
1039                         _("Counting distinct commits in commit graph"),
1040                         ctx->oids.nr);
1041         display_progress(ctx->progress, 0); /* TODO: Measure QSORT() progress */
1042         QSORT(ctx->oids.list, ctx->oids.nr, oid_compare);
1043
1044         for (i = 1; i < ctx->oids.nr; i++) {
1045                 display_progress(ctx->progress, i + 1);
1046                 if (!oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i]))
1047                         count_distinct++;
1048         }
1049         stop_progress(&ctx->progress);
1050
1051         return count_distinct;
1052 }
1053
1054 static void copy_oids_to_commits(struct write_commit_graph_context *ctx)
1055 {
1056         uint32_t i;
1057         struct commit_list *parent;
1058
1059         ctx->num_extra_edges = 0;
1060         if (ctx->report_progress)
1061                 ctx->progress = start_delayed_progress(
1062                         _("Finding extra edges in commit graph"),
1063                         ctx->oids.nr);
1064         for (i = 0; i < ctx->oids.nr; i++) {
1065                 int num_parents = 0;
1066                 display_progress(ctx->progress, i + 1);
1067                 if (i > 0 && oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i]))
1068                         continue;
1069
1070                 ctx->commits.list[ctx->commits.nr] = lookup_commit(ctx->r, &ctx->oids.list[i]);
1071                 parse_commit_no_graph(ctx->commits.list[ctx->commits.nr]);
1072
1073                 for (parent = ctx->commits.list[ctx->commits.nr]->parents;
1074                      parent; parent = parent->next)
1075                         num_parents++;
1076
1077                 if (num_parents > 2)
1078                         ctx->num_extra_edges += num_parents - 1;
1079
1080                 ctx->commits.nr++;
1081         }
1082         stop_progress(&ctx->progress);
1083 }
1084
1085 static int write_commit_graph_file(struct write_commit_graph_context *ctx)
1086 {
1087         uint32_t i;
1088         struct hashfile *f;
1089         struct lock_file lk = LOCK_INIT;
1090         uint32_t chunk_ids[5];
1091         uint64_t chunk_offsets[5];
1092         const unsigned hashsz = the_hash_algo->rawsz;
1093         struct strbuf progress_title = STRBUF_INIT;
1094         int num_chunks = ctx->num_extra_edges ? 4 : 3;
1095
1096         ctx->graph_name = get_commit_graph_filename(ctx->obj_dir);
1097         if (safe_create_leading_directories(ctx->graph_name)) {
1098                 UNLEAK(ctx->graph_name);
1099                 error(_("unable to create leading directories of %s"),
1100                         ctx->graph_name);
1101                 return -1;
1102         }
1103
1104         hold_lock_file_for_update(&lk, ctx->graph_name, LOCK_DIE_ON_ERROR);
1105         f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
1106
1107         hashwrite_be32(f, GRAPH_SIGNATURE);
1108
1109         hashwrite_u8(f, GRAPH_VERSION);
1110         hashwrite_u8(f, oid_version());
1111         hashwrite_u8(f, num_chunks);
1112         hashwrite_u8(f, 0); /* unused padding byte */
1113
1114         chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
1115         chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
1116         chunk_ids[2] = GRAPH_CHUNKID_DATA;
1117         if (ctx->num_extra_edges)
1118                 chunk_ids[3] = GRAPH_CHUNKID_EXTRAEDGES;
1119         else
1120                 chunk_ids[3] = 0;
1121         chunk_ids[4] = 0;
1122
1123         chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
1124         chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
1125         chunk_offsets[2] = chunk_offsets[1] + hashsz * ctx->commits.nr;
1126         chunk_offsets[3] = chunk_offsets[2] + (hashsz + 16) * ctx->commits.nr;
1127         chunk_offsets[4] = chunk_offsets[3] + 4 * ctx->num_extra_edges;
1128
1129         for (i = 0; i <= num_chunks; i++) {
1130                 uint32_t chunk_write[3];
1131
1132                 chunk_write[0] = htonl(chunk_ids[i]);
1133                 chunk_write[1] = htonl(chunk_offsets[i] >> 32);
1134                 chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
1135                 hashwrite(f, chunk_write, 12);
1136         }
1137
1138         if (ctx->report_progress) {
1139                 strbuf_addf(&progress_title,
1140                             Q_("Writing out commit graph in %d pass",
1141                                "Writing out commit graph in %d passes",
1142                                num_chunks),
1143                             num_chunks);
1144                 ctx->progress = start_delayed_progress(
1145                         progress_title.buf,
1146                         num_chunks * ctx->commits.nr);
1147         }
1148         write_graph_chunk_fanout(f, ctx);
1149         write_graph_chunk_oids(f, hashsz, ctx);
1150         write_graph_chunk_data(f, hashsz, ctx);
1151         if (ctx->num_extra_edges)
1152                 write_graph_chunk_extra_edges(f, ctx);
1153         stop_progress(&ctx->progress);
1154         strbuf_release(&progress_title);
1155
1156         close_commit_graph(ctx->r->objects);
1157         finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
1158         commit_lock_file(&lk);
1159
1160         return 0;
1161 }
1162
1163 int write_commit_graph(const char *obj_dir,
1164                        struct string_list *pack_indexes,
1165                        struct string_list *commit_hex,
1166                        unsigned int flags)
1167 {
1168         struct write_commit_graph_context *ctx;
1169         uint32_t i, count_distinct = 0;
1170         int res = 0;
1171
1172         if (!commit_graph_compatible(the_repository))
1173                 return 0;
1174
1175         ctx = xcalloc(1, sizeof(struct write_commit_graph_context));
1176         ctx->r = the_repository;
1177         ctx->obj_dir = obj_dir;
1178         ctx->append = flags & COMMIT_GRAPH_APPEND ? 1 : 0;
1179         ctx->report_progress = flags & COMMIT_GRAPH_PROGRESS ? 1 : 0;
1180
1181         ctx->approx_nr_objects = approximate_object_count();
1182         ctx->oids.alloc = ctx->approx_nr_objects / 32;
1183
1184         if (ctx->append) {
1185                 prepare_commit_graph_one(ctx->r, ctx->obj_dir);
1186                 if (ctx->r->objects->commit_graph)
1187                         ctx->oids.alloc += ctx->r->objects->commit_graph->num_commits;
1188         }
1189
1190         if (ctx->oids.alloc < 1024)
1191                 ctx->oids.alloc = 1024;
1192         ALLOC_ARRAY(ctx->oids.list, ctx->oids.alloc);
1193
1194         if (ctx->append && ctx->r->objects->commit_graph) {
1195                 struct commit_graph *g = ctx->r->objects->commit_graph;
1196                 for (i = 0; i < g->num_commits; i++) {
1197                         const unsigned char *hash = g->chunk_oid_lookup + g->hash_len * i;
1198                         hashcpy(ctx->oids.list[ctx->oids.nr++].hash, hash);
1199                 }
1200         }
1201
1202         if (pack_indexes) {
1203                 if ((res = fill_oids_from_packs(ctx, pack_indexes)))
1204                         goto cleanup;
1205         }
1206
1207         if (commit_hex)
1208                 fill_oids_from_commit_hex(ctx, commit_hex);
1209
1210         if (!pack_indexes && !commit_hex)
1211                 fill_oids_from_all_packs(ctx);
1212
1213         close_reachable(ctx);
1214
1215         count_distinct = count_distinct_commits(ctx);
1216
1217         if (count_distinct >= GRAPH_EDGE_LAST_MASK) {
1218                 error(_("the commit graph format cannot write %d commits"), count_distinct);
1219                 res = -1;
1220                 goto cleanup;
1221         }
1222
1223         ctx->commits.alloc = count_distinct;
1224         ALLOC_ARRAY(ctx->commits.list, ctx->commits.alloc);
1225
1226         copy_oids_to_commits(ctx);
1227
1228         if (ctx->commits.nr >= GRAPH_EDGE_LAST_MASK) {
1229                 error(_("too many commits to write graph"));
1230                 res = -1;
1231                 goto cleanup;
1232         }
1233
1234         compute_generation_numbers(ctx);
1235
1236         res = write_commit_graph_file(ctx);
1237
1238 cleanup:
1239         free(ctx->graph_name);
1240         free(ctx->commits.list);
1241         free(ctx->oids.list);
1242         free(ctx);
1243
1244         return res;
1245 }
1246
1247 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
1248 static int verify_commit_graph_error;
1249
1250 static void graph_report(const char *fmt, ...)
1251 {
1252         va_list ap;
1253
1254         verify_commit_graph_error = 1;
1255         va_start(ap, fmt);
1256         vfprintf(stderr, fmt, ap);
1257         fprintf(stderr, "\n");
1258         va_end(ap);
1259 }
1260
1261 #define GENERATION_ZERO_EXISTS 1
1262 #define GENERATION_NUMBER_EXISTS 2
1263
1264 int verify_commit_graph(struct repository *r, struct commit_graph *g)
1265 {
1266         uint32_t i, cur_fanout_pos = 0;
1267         struct object_id prev_oid, cur_oid, checksum;
1268         int generation_zero = 0;
1269         struct hashfile *f;
1270         int devnull;
1271         struct progress *progress = NULL;
1272
1273         if (!g) {
1274                 graph_report("no commit-graph file loaded");
1275                 return 1;
1276         }
1277
1278         verify_commit_graph_error = verify_commit_graph_lite(g);
1279         if (verify_commit_graph_error)
1280                 return verify_commit_graph_error;
1281
1282         devnull = open("/dev/null", O_WRONLY);
1283         f = hashfd(devnull, NULL);
1284         hashwrite(f, g->data, g->data_len - g->hash_len);
1285         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
1286         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
1287                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
1288                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
1289         }
1290
1291         for (i = 0; i < g->num_commits; i++) {
1292                 struct commit *graph_commit;
1293
1294                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1295
1296                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
1297                         graph_report(_("commit-graph has incorrect OID order: %s then %s"),
1298                                      oid_to_hex(&prev_oid),
1299                                      oid_to_hex(&cur_oid));
1300
1301                 oidcpy(&prev_oid, &cur_oid);
1302
1303                 while (cur_oid.hash[0] > cur_fanout_pos) {
1304                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1305
1306                         if (i != fanout_value)
1307                                 graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
1308                                              cur_fanout_pos, fanout_value, i);
1309                         cur_fanout_pos++;
1310                 }
1311
1312                 graph_commit = lookup_commit(r, &cur_oid);
1313                 if (!parse_commit_in_graph_one(r, g, graph_commit))
1314                         graph_report(_("failed to parse commit %s from commit-graph"),
1315                                      oid_to_hex(&cur_oid));
1316         }
1317
1318         while (cur_fanout_pos < 256) {
1319                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1320
1321                 if (g->num_commits != fanout_value)
1322                         graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
1323                                      cur_fanout_pos, fanout_value, i);
1324
1325                 cur_fanout_pos++;
1326         }
1327
1328         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
1329                 return verify_commit_graph_error;
1330
1331         progress = start_progress(_("Verifying commits in commit graph"),
1332                                   g->num_commits);
1333         for (i = 0; i < g->num_commits; i++) {
1334                 struct commit *graph_commit, *odb_commit;
1335                 struct commit_list *graph_parents, *odb_parents;
1336                 uint32_t max_generation = 0;
1337
1338                 display_progress(progress, i + 1);
1339                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1340
1341                 graph_commit = lookup_commit(r, &cur_oid);
1342                 odb_commit = (struct commit *)create_object(r, cur_oid.hash, alloc_commit_node(r));
1343                 if (parse_commit_internal(odb_commit, 0, 0)) {
1344                         graph_report(_("failed to parse commit %s from object database for commit-graph"),
1345                                      oid_to_hex(&cur_oid));
1346                         continue;
1347                 }
1348
1349                 if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
1350                            get_commit_tree_oid(odb_commit)))
1351                         graph_report(_("root tree OID for commit %s in commit-graph is %s != %s"),
1352                                      oid_to_hex(&cur_oid),
1353                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
1354                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
1355
1356                 graph_parents = graph_commit->parents;
1357                 odb_parents = odb_commit->parents;
1358
1359                 while (graph_parents) {
1360                         if (odb_parents == NULL) {
1361                                 graph_report(_("commit-graph parent list for commit %s is too long"),
1362                                              oid_to_hex(&cur_oid));
1363                                 break;
1364                         }
1365
1366                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
1367                                 graph_report(_("commit-graph parent for %s is %s != %s"),
1368                                              oid_to_hex(&cur_oid),
1369                                              oid_to_hex(&graph_parents->item->object.oid),
1370                                              oid_to_hex(&odb_parents->item->object.oid));
1371
1372                         if (graph_parents->item->generation > max_generation)
1373                                 max_generation = graph_parents->item->generation;
1374
1375                         graph_parents = graph_parents->next;
1376                         odb_parents = odb_parents->next;
1377                 }
1378
1379                 if (odb_parents != NULL)
1380                         graph_report(_("commit-graph parent list for commit %s terminates early"),
1381                                      oid_to_hex(&cur_oid));
1382
1383                 if (!graph_commit->generation) {
1384                         if (generation_zero == GENERATION_NUMBER_EXISTS)
1385                                 graph_report(_("commit-graph has generation number zero for commit %s, but non-zero elsewhere"),
1386                                              oid_to_hex(&cur_oid));
1387                         generation_zero = GENERATION_ZERO_EXISTS;
1388                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
1389                         graph_report(_("commit-graph has non-zero generation number for commit %s, but zero elsewhere"),
1390                                      oid_to_hex(&cur_oid));
1391
1392                 if (generation_zero == GENERATION_ZERO_EXISTS)
1393                         continue;
1394
1395                 /*
1396                  * If one of our parents has generation GENERATION_NUMBER_MAX, then
1397                  * our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
1398                  * extra logic in the following condition.
1399                  */
1400                 if (max_generation == GENERATION_NUMBER_MAX)
1401                         max_generation--;
1402
1403                 if (graph_commit->generation != max_generation + 1)
1404                         graph_report(_("commit-graph generation for commit %s is %u != %u"),
1405                                      oid_to_hex(&cur_oid),
1406                                      graph_commit->generation,
1407                                      max_generation + 1);
1408
1409                 if (graph_commit->date != odb_commit->date)
1410                         graph_report(_("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime),
1411                                      oid_to_hex(&cur_oid),
1412                                      graph_commit->date,
1413                                      odb_commit->date);
1414         }
1415         stop_progress(&progress);
1416
1417         return verify_commit_graph_error;
1418 }
1419
1420 void free_commit_graph(struct commit_graph *g)
1421 {
1422         if (!g)
1423                 return;
1424         if (g->graph_fd >= 0) {
1425                 munmap((void *)g->data, g->data_len);
1426                 g->data = NULL;
1427                 close(g->graph_fd);
1428         }
1429         free(g);
1430 }