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 #define GRAPH_CHUNKID_BASE 0x42415345 /* "BASE" */
  26
  27 #define GRAPH_DATA_WIDTH (the_hash_algo->rawsz + 16)
  28
  29 #define GRAPH_VERSION_1 0x1
  30 #define GRAPH_VERSION GRAPH_VERSION_1
  31
  32 #define GRAPH_EXTRA_EDGES_NEEDED 0x80000000
  33 #define GRAPH_EDGE_LAST_MASK 0x7fffffff
  34 #define GRAPH_PARENT_NONE 0x70000000
  35
  36 #define GRAPH_LAST_EDGE 0x80000000
  37
  38 #define GRAPH_HEADER_SIZE 8
  39 #define GRAPH_FANOUT_SIZE (4 * 256)
  40 #define GRAPH_CHUNKLOOKUP_WIDTH 12
  41 #define GRAPH_MIN_SIZE (GRAPH_HEADER_SIZE + 4 * GRAPH_CHUNKLOOKUP_WIDTH \
  42                         + GRAPH_FANOUT_SIZE + the_hash_algo->rawsz)
  43
  44 char *get_commit_graph_filename(const char *obj_dir)
  45 {
  46         char *filename = xstrfmt("%s/info/commit-graph", obj_dir);
  47         char *normalized = xmalloc(strlen(filename) + 1);
  48         normalize_path_copy(normalized, filename);
  49         free(filename);
  50         return normalized;
  51 }
  52
  53 static char *get_split_graph_filename(const char *obj_dir,
  54                                       const char *oid_hex)
  55 {
  56         char *filename = xstrfmt("%s/info/commit-graphs/graph-%s.graph",
  57                                  obj_dir,
  58                                  oid_hex);
  59         char *normalized = xmalloc(strlen(filename) + 1);
  60         normalize_path_copy(normalized, filename);
  61         free(filename);
  62         return normalized;
  63 }
  64
  65 static char *get_chain_filename(const char *obj_dir)
  66 {
  67         return xstrfmt("%s/info/commit-graphs/commit-graph-chain", obj_dir);
  68 }
  69
  70 static uint8_t oid_version(void)
  71 {
  72         return 1;
  73 }
  74
  75 static struct commit_graph *alloc_commit_graph(void)
  76 {
  77         struct commit_graph *g = xcalloc(1, sizeof(*g));
  78         g->graph_fd = -1;
  79
  80         return g;
  81 }
  82
  83 extern int read_replace_refs;
  84
  85 static int commit_graph_compatible(struct repository *r)
  86 {
  87         if (!r->gitdir)
  88                 return 0;
  89
  90         if (read_replace_refs) {
  91                 prepare_replace_object(r);
  92                 if (hashmap_get_size(&r->objects->replace_map->map))
  93                         return 0;
  94         }
  95
  96         prepare_commit_graft(r);
  97         if (r->parsed_objects && r->parsed_objects->grafts_nr)
  98                 return 0;
  99         if (is_repository_shallow(r))
 100                 return 0;
 101
 102         return 1;
 103 }
 104
 105 int open_commit_graph(const char *graph_file, int *fd, struct stat *st)
 106 {
 107         *fd = git_open(graph_file);
 108         if (*fd < 0)
 109                 return 0;
 110         if (fstat(*fd, st)) {
 111                 close(*fd);
 112                 return 0;
 113         }
 114         return 1;
 115 }
 116
 117 struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st)
 118 {
 119         void *graph_map;
 120         size_t graph_size;
 121         struct commit_graph *ret;
 122
 123         graph_size = xsize_t(st->st_size);
 124
 125         if (graph_size < GRAPH_MIN_SIZE) {
 126                 close(fd);
 127                 error(_("commit-graph file is too small"));
 128                 return NULL;
 129         }
 130         graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
 131         ret = parse_commit_graph(graph_map, fd, graph_size);
 132
 133         if (!ret) {
 134                 munmap(graph_map, graph_size);
 135                 close(fd);
 136         }
 137
 138         return ret;
 139 }
 140
 141 static int verify_commit_graph_lite(struct commit_graph *g)
 142 {
 143         /*
 144          * Basic validation shared between parse_commit_graph()
 145          * which'll be called every time the graph is used, and the
 146          * much more expensive verify_commit_graph() used by
 147          * "commit-graph verify".
 148          *
 149          * There should only be very basic checks here to ensure that
 150          * we don't e.g. segfault in fill_commit_in_graph(), but
 151          * because this is a very hot codepath nothing that e.g. loops
 152          * over g->num_commits, or runs a checksum on the commit-graph
 153          * itself.
 154          */
 155         if (!g->chunk_oid_fanout) {
 156                 error("commit-graph is missing the OID Fanout chunk");
 157                 return 1;
 158         }
 159         if (!g->chunk_oid_lookup) {
 160                 error("commit-graph is missing the OID Lookup chunk");
 161                 return 1;
 162         }
 163         if (!g->chunk_commit_data) {
 164                 error("commit-graph is missing the Commit Data chunk");
 165                 return 1;
 166         }
 167
 168         return 0;
 169 }
 170
 171 struct commit_graph *parse_commit_graph(void *graph_map, int fd,
 172                                         size_t graph_size)
 173 {
 174         const unsigned char *data, *chunk_lookup;
 175         uint32_t i;
 176         struct commit_graph *graph;
 177         uint64_t last_chunk_offset;
 178         uint32_t last_chunk_id;
 179         uint32_t graph_signature;
 180         unsigned char graph_version, hash_version;
 181
 182         if (!graph_map)
 183                 return NULL;
 184
 185         if (graph_size < GRAPH_MIN_SIZE)
 186                 return NULL;
 187
 188         data = (const unsigned char *)graph_map;
 189
 190         graph_signature = get_be32(data);
 191         if (graph_signature != GRAPH_SIGNATURE) {
 192                 error(_("commit-graph signature %X does not match signature %X"),
 193                       graph_signature, GRAPH_SIGNATURE);
 194                 return NULL;
 195         }
 196
 197         graph_version = *(unsigned char*)(data + 4);
 198         if (graph_version != GRAPH_VERSION) {
 199                 error(_("commit-graph version %X does not match version %X"),
 200                       graph_version, GRAPH_VERSION);
 201                 return NULL;
 202         }
 203
 204         hash_version = *(unsigned char*)(data + 5);
 205         if (hash_version != oid_version()) {
 206                 error(_("commit-graph hash version %X does not match version %X"),
 207                       hash_version, oid_version());
 208                 return NULL;
 209         }
 210
 211         graph = alloc_commit_graph();
 212
 213         graph->hash_len = the_hash_algo->rawsz;
 214         graph->num_chunks = *(unsigned char*)(data + 6);
 215         graph->graph_fd = fd;
 216         graph->data = graph_map;
 217         graph->data_len = graph_size;
 218
 219         last_chunk_id = 0;
 220         last_chunk_offset = 8;
 221         chunk_lookup = data + 8;
 222         for (i = 0; i < graph->num_chunks; i++) {
 223                 uint32_t chunk_id;
 224                 uint64_t chunk_offset;
 225                 int chunk_repeated = 0;
 226
 227                 if (data + graph_size - chunk_lookup <
 228                     GRAPH_CHUNKLOOKUP_WIDTH) {
 229                         error(_("commit-graph chunk lookup table entry missing; file may be incomplete"));
 230                         free(graph);
 231                         return NULL;
 232                 }
 233
 234                 chunk_id = get_be32(chunk_lookup + 0);
 235                 chunk_offset = get_be64(chunk_lookup + 4);
 236
 237                 chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
 238
 239                 if (chunk_offset > graph_size - the_hash_algo->rawsz) {
 240                         error(_("commit-graph improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
 241                               (uint32_t)chunk_offset);
 242                         free(graph);
 243                         return NULL;
 244                 }
 245
 246                 switch (chunk_id) {
 247                 case GRAPH_CHUNKID_OIDFANOUT:
 248                         if (graph->chunk_oid_fanout)
 249                                 chunk_repeated = 1;
 250                         else
 251                                 graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
 252                         break;
 253
 254                 case GRAPH_CHUNKID_OIDLOOKUP:
 255                         if (graph->chunk_oid_lookup)
 256                                 chunk_repeated = 1;
 257                         else
 258                                 graph->chunk_oid_lookup = data + chunk_offset;
 259                         break;
 260
 261                 case GRAPH_CHUNKID_DATA:
 262                         if (graph->chunk_commit_data)
 263                                 chunk_repeated = 1;
 264                         else
 265                                 graph->chunk_commit_data = data + chunk_offset;
 266                         break;
 267
 268                 case GRAPH_CHUNKID_EXTRAEDGES:
 269                         if (graph->chunk_extra_edges)
 270                                 chunk_repeated = 1;
 271                         else
 272                                 graph->chunk_extra_edges = data + chunk_offset;
 273                         break;
 274
 275                 case GRAPH_CHUNKID_BASE:
 276                         if (graph->chunk_base_graphs)
 277                                 chunk_repeated = 1;
 278                         else
 279                                 graph->chunk_base_graphs = data + chunk_offset;
 280                 }
 281
 282                 if (chunk_repeated) {
 283                         error(_("commit-graph chunk id %08x appears multiple times"), chunk_id);
 284                         free(graph);
 285                         return NULL;
 286                 }
 287
 288                 if (last_chunk_id == GRAPH_CHUNKID_OIDLOOKUP)
 289                 {
 290                         graph->num_commits = (chunk_offset - last_chunk_offset)
 291                                              / graph->hash_len;
 292                 }
 293
 294                 last_chunk_id = chunk_id;
 295                 last_chunk_offset = chunk_offset;
 296         }
 297
 298         hashcpy(graph->oid.hash, graph->data + graph->data_len - graph->hash_len);
 299
 300         if (verify_commit_graph_lite(graph))
 301                 return NULL;
 302
 303         return graph;
 304 }
 305
 306 static struct commit_graph *load_commit_graph_one(const char *graph_file)
 307 {
 308
 309         struct stat st;
 310         int fd;
 311         struct commit_graph *g;
 312         int open_ok = open_commit_graph(graph_file, &fd, &st);
 313
 314         if (!open_ok)
 315                 return NULL;
 316
 317         g = load_commit_graph_one_fd_st(fd, &st);
 318
 319         if (g)
 320                 g->filename = xstrdup(graph_file);
 321
 322         return g;
 323 }
 324
 325 static struct commit_graph *load_commit_graph_v1(struct repository *r, const char *obj_dir)
 326 {
 327         char *graph_name = get_commit_graph_filename(obj_dir);
 328         struct commit_graph *g = load_commit_graph_one(graph_name);
 329         free(graph_name);
 330
 331         if (g)
 332                 g->obj_dir = obj_dir;
 333
 334         return g;
 335 }
 336
 337 static int add_graph_to_chain(struct commit_graph *g,
 338                               struct commit_graph *chain,
 339                               struct object_id *oids,
 340                               int n)
 341 {
 342         struct commit_graph *cur_g = chain;
 343
 344         if (n && !g->chunk_base_graphs) {
 345                 warning(_("commit-graph has no base graphs chunk"));
 346                 return 0;
 347         }
 348
 349         while (n) {
 350                 n--;
 351
 352                 if (!cur_g ||
 353                     !oideq(&oids[n], &cur_g->oid) ||
 354                     !hasheq(oids[n].hash, g->chunk_base_graphs + g->hash_len * n)) {
 355                         warning(_("commit-graph chain does not match"));
 356                         return 0;
 357                 }
 358
 359                 cur_g = cur_g->base_graph;
 360         }
 361
 362         g->base_graph = chain;
 363
 364         if (chain)
 365                 g->num_commits_in_base = chain->num_commits + chain->num_commits_in_base;
 366
 367         return 1;
 368 }
 369
 370 static struct commit_graph *load_commit_graph_chain(struct repository *r, const char *obj_dir)
 371 {
 372         struct commit_graph *graph_chain = NULL;
 373         struct strbuf line = STRBUF_INIT;
 374         struct stat st;
 375         struct object_id *oids;
 376         int i = 0, valid = 1, count;
 377         char *chain_name = get_chain_filename(obj_dir);
 378         FILE *fp;
 379         int stat_res;
 380
 381         fp = fopen(chain_name, "r");
 382         stat_res = stat(chain_name, &st);
 383         free(chain_name);
 384
 385         if (!fp ||
 386             stat_res ||
 387             st.st_size <= the_hash_algo->hexsz)
 388                 return NULL;
 389
 390         count = st.st_size / (the_hash_algo->hexsz + 1);
 391         oids = xcalloc(count, sizeof(struct object_id));
 392
 393         prepare_alt_odb(r);
 394
 395         for (i = 0; i < count; i++) {
 396                 struct object_directory *odb;
 397
 398                 if (strbuf_getline_lf(&line, fp) == EOF)
 399                         break;
 400
 401                 if (get_oid_hex(line.buf, &oids[i])) {
 402                         warning(_("invalid commit-graph chain: line '%s' not a hash"),
 403                                 line.buf);
 404                         valid = 0;
 405                         break;
 406                 }
 407
 408                 valid = 0;
 409                 for (odb = r->objects->odb; odb; odb = odb->next) {
 410                         char *graph_name = get_split_graph_filename(odb->path, line.buf);
 411                         struct commit_graph *g = load_commit_graph_one(graph_name);
 412
 413                         free(graph_name);
 414
 415                         if (g) {
 416                                 g->obj_dir = odb->path;
 417
 418                                 if (add_graph_to_chain(g, graph_chain, oids, i)) {
 419                                         graph_chain = g;
 420                                         valid = 1;
 421                                 }
 422
 423                                 break;
 424                         }
 425                 }
 426
 427                 if (!valid) {
 428                         warning(_("unable to find all commit-graph files"));
 429                         break;
 430                 }
 431         }
 432
 433         free(oids);
 434         fclose(fp);
 435         strbuf_release(&line);
 436
 437         return graph_chain;
 438 }
 439
 440 struct commit_graph *read_commit_graph_one(struct repository *r, const char *obj_dir)
 441 {
 442         struct commit_graph *g = load_commit_graph_v1(r, obj_dir);
 443
 444         if (!g)
 445                 g = load_commit_graph_chain(r, obj_dir);
 446
 447         return g;
 448 }
 449
 450 static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
 451 {
 452
 453         if (r->objects->commit_graph)
 454                 return;
 455
 456         r->objects->commit_graph = read_commit_graph_one(r, obj_dir);
 457 }
 458
 459 /*
 460  * Return 1 if commit_graph is non-NULL, and 0 otherwise.
 461  *
 462  * On the first invocation, this function attemps to load the commit
 463  * graph if the_repository is configured to have one.
 464  */
 465 static int prepare_commit_graph(struct repository *r)
 466 {
 467         struct object_directory *odb;
 468         int config_value;
 469
 470         if (git_env_bool(GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD, 0))
 471                 die("dying as requested by the '%s' variable on commit-graph load!",
 472                     GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD);
 473
 474         if (r->objects->commit_graph_attempted)
 475                 return !!r->objects->commit_graph;
 476         r->objects->commit_graph_attempted = 1;
 477
 478         if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
 479             (repo_config_get_bool(r, "core.commitgraph", &config_value) ||
 480             !config_value))
 481                 /*
 482                  * This repository is not configured to use commit graphs, so
 483                  * do not load one. (But report commit_graph_attempted anyway
 484                  * so that commit graph loading is not attempted again for this
 485                  * repository.)
 486                  */
 487                 return 0;
 488
 489         if (!commit_graph_compatible(r))
 490                 return 0;
 491
 492         prepare_alt_odb(r);
 493         for (odb = r->objects->odb;
 494              !r->objects->commit_graph && odb;
 495              odb = odb->next)
 496                 prepare_commit_graph_one(r, odb->path);
 497         return !!r->objects->commit_graph;
 498 }
 499
 500 int generation_numbers_enabled(struct repository *r)
 501 {
 502         uint32_t first_generation;
 503         struct commit_graph *g;
 504         if (!prepare_commit_graph(r))
 505                return 0;
 506
 507         g = r->objects->commit_graph;
 508
 509         if (!g->num_commits)
 510                 return 0;
 511
 512         first_generation = get_be32(g->chunk_commit_data +
 513                                     g->hash_len + 8) >> 2;
 514
 515         return !!first_generation;
 516 }
 517
 518 static void close_commit_graph_one(struct commit_graph *g)
 519 {
 520         if (!g)
 521                 return;
 522
 523         close_commit_graph_one(g->base_graph);
 524         free_commit_graph(g);
 525 }
 526
 527 void close_commit_graph(struct raw_object_store *o)
 528 {
 529         close_commit_graph_one(o->commit_graph);
 530         o->commit_graph = NULL;
 531 }
 532
 533 static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
 534 {
 535         return bsearch_hash(oid->hash, g->chunk_oid_fanout,
 536                             g->chunk_oid_lookup, g->hash_len, pos);
 537 }
 538
 539 static void load_oid_from_graph(struct commit_graph *g,
 540                                 uint32_t pos,
 541                                 struct object_id *oid)
 542 {
 543         uint32_t lex_index;
 544
 545         while (g && pos < g->num_commits_in_base)
 546                 g = g->base_graph;
 547
 548         if (!g)
 549                 BUG("NULL commit-graph");
 550
 551         if (pos >= g->num_commits + g->num_commits_in_base)
 552                 die(_("invalid commit position. commit-graph is likely corrupt"));
 553
 554         lex_index = pos - g->num_commits_in_base;
 555
 556         hashcpy(oid->hash, g->chunk_oid_lookup + g->hash_len * lex_index);
 557 }
 558
 559 static struct commit_list **insert_parent_or_die(struct repository *r,
 560                                                  struct commit_graph *g,
 561                                                  uint32_t pos,
 562                                                  struct commit_list **pptr)
 563 {
 564         struct commit *c;
 565         struct object_id oid;
 566
 567         if (pos >= g->num_commits + g->num_commits_in_base)
 568                 die("invalid parent position %"PRIu32, pos);
 569
 570         load_oid_from_graph(g, pos, &oid);
 571         c = lookup_commit(r, &oid);
 572         if (!c)
 573                 die(_("could not find commit %s"), oid_to_hex(&oid));
 574         c->graph_pos = pos;
 575         return &commit_list_insert(c, pptr)->next;
 576 }
 577
 578 static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
 579 {
 580         const unsigned char *commit_data;
 581         uint32_t lex_index;
 582
 583         while (pos < g->num_commits_in_base)
 584                 g = g->base_graph;
 585
 586         lex_index = pos - g->num_commits_in_base;
 587         commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * lex_index;
 588         item->graph_pos = pos;
 589         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 590 }
 591
 592 static int fill_commit_in_graph(struct repository *r,
 593                                 struct commit *item,
 594                                 struct commit_graph *g, uint32_t pos)
 595 {
 596         uint32_t edge_value;
 597         uint32_t *parent_data_ptr;
 598         uint64_t date_low, date_high;
 599         struct commit_list **pptr;
 600         const unsigned char *commit_data;
 601         uint32_t lex_index;
 602
 603         while (pos < g->num_commits_in_base)
 604                 g = g->base_graph;
 605
 606         if (pos >= g->num_commits + g->num_commits_in_base)
 607                 die(_("invalid commit position. commit-graph is likely corrupt"));
 608
 609         /*
 610          * Store the "full" position, but then use the
 611          * "local" position for the rest of the calculation.
 612          */
 613         item->graph_pos = pos;
 614         lex_index = pos - g->num_commits_in_base;
 615
 616         commit_data = g->chunk_commit_data + (g->hash_len + 16) * lex_index;
 617
 618         item->object.parsed = 1;
 619
 620         item->maybe_tree = NULL;
 621
 622         date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
 623         date_low = get_be32(commit_data + g->hash_len + 12);
 624         item->date = (timestamp_t)((date_high << 32) | date_low);
 625
 626         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 627
 628         pptr = &item->parents;
 629
 630         edge_value = get_be32(commit_data + g->hash_len);
 631         if (edge_value == GRAPH_PARENT_NONE)
 632                 return 1;
 633         pptr = insert_parent_or_die(r, g, edge_value, pptr);
 634
 635         edge_value = get_be32(commit_data + g->hash_len + 4);
 636         if (edge_value == GRAPH_PARENT_NONE)
 637                 return 1;
 638         if (!(edge_value & GRAPH_EXTRA_EDGES_NEEDED)) {
 639                 pptr = insert_parent_or_die(r, g, edge_value, pptr);
 640                 return 1;
 641         }
 642
 643         parent_data_ptr = (uint32_t*)(g->chunk_extra_edges +
 644                           4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
 645         do {
 646                 edge_value = get_be32(parent_data_ptr);
 647                 pptr = insert_parent_or_die(r, g,
 648                                             edge_value & GRAPH_EDGE_LAST_MASK,
 649                                             pptr);
 650                 parent_data_ptr++;
 651         } while (!(edge_value & GRAPH_LAST_EDGE));
 652
 653         return 1;
 654 }
 655
 656 static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 657 {
 658         if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
 659                 *pos = item->graph_pos;
 660                 return 1;
 661         } else {
 662                 struct commit_graph *cur_g = g;
 663                 uint32_t lex_index;
 664
 665                 while (cur_g && !bsearch_graph(cur_g, &(item->object.oid), &lex_index))
 666                         cur_g = cur_g->base_graph;
 667
 668                 if (cur_g) {
 669                         *pos = lex_index + cur_g->num_commits_in_base;
 670                         return 1;
 671                 }
 672
 673                 return 0;
 674         }
 675 }
 676
 677 static int parse_commit_in_graph_one(struct repository *r,
 678                                      struct commit_graph *g,
 679                                      struct commit *item)
 680 {
 681         uint32_t pos;
 682
 683         if (item->object.parsed)
 684                 return 1;
 685
 686         if (find_commit_in_graph(item, g, &pos))
 687                 return fill_commit_in_graph(r, item, g, pos);
 688
 689         return 0;
 690 }
 691
 692 int parse_commit_in_graph(struct repository *r, struct commit *item)
 693 {
 694         if (!prepare_commit_graph(r))
 695                 return 0;
 696         return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
 697 }
 698
 699 void load_commit_graph_info(struct repository *r, struct commit *item)
 700 {
 701         uint32_t pos;
 702         if (!prepare_commit_graph(r))
 703                 return;
 704         if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
 705                 fill_commit_graph_info(item, r->objects->commit_graph, pos);
 706 }
 707
 708 static struct tree *load_tree_for_commit(struct repository *r,
 709                                          struct commit_graph *g,
 710                                          struct commit *c)
 711 {
 712         struct object_id oid;
 713         const unsigned char *commit_data;
 714
 715         while (c->graph_pos < g->num_commits_in_base)
 716                 g = g->base_graph;
 717
 718         commit_data = g->chunk_commit_data +
 719                         GRAPH_DATA_WIDTH * (c->graph_pos - g->num_commits_in_base);
 720
 721         hashcpy(oid.hash, commit_data);
 722         c->maybe_tree = lookup_tree(r, &oid);
 723
 724         return c->maybe_tree;
 725 }
 726
 727 static struct tree *get_commit_tree_in_graph_one(struct repository *r,
 728                                                  struct commit_graph *g,
 729                                                  const struct commit *c)
 730 {
 731         if (c->maybe_tree)
 732                 return c->maybe_tree;
 733         if (c->graph_pos == COMMIT_NOT_FROM_GRAPH)
 734                 BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
 735
 736         return load_tree_for_commit(r, g, (struct commit *)c);
 737 }
 738
 739 struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
 740 {
 741         return get_commit_tree_in_graph_one(r, r->objects->commit_graph, c);
 742 }
 743
 744 struct packed_commit_list {
 745         struct commit **list;
 746         int nr;
 747         int alloc;
 748 };
 749
 750 struct packed_oid_list {
 751         struct object_id *list;
 752         int nr;
 753         int alloc;
 754 };
 755
 756 struct write_commit_graph_context {
 757         struct repository *r;
 758         char *obj_dir;
 759         char *graph_name;
 760         struct packed_oid_list oids;
 761         struct packed_commit_list commits;
 762         int num_extra_edges;
 763         unsigned long approx_nr_objects;
 764         struct progress *progress;
 765         int progress_done;
 766         uint64_t progress_cnt;
 767
 768         char *base_graph_name;
 769         int num_commit_graphs_before;
 770         int num_commit_graphs_after;
 771         char **commit_graph_filenames_before;
 772         char **commit_graph_filenames_after;
 773         char **commit_graph_hash_after;
 774         uint32_t new_num_commits_in_base;
 775         struct commit_graph *new_base_graph;
 776
 777         unsigned append:1,
 778                  report_progress:1,
 779                  split:1;
 780
 781         const struct split_commit_graph_opts *split_opts;
 782 };
 783
 784 static void write_graph_chunk_fanout(struct hashfile *f,
 785                                      struct write_commit_graph_context *ctx)
 786 {
 787         int i, count = 0;
 788         struct commit **list = ctx->commits.list;
 789
 790         /*
 791          * Write the first-level table (the list is sorted,
 792          * but we use a 256-entry lookup to be able to avoid
 793          * having to do eight extra binary search iterations).
 794          */
 795         for (i = 0; i < 256; i++) {
 796                 while (count < ctx->commits.nr) {
 797                         if ((*list)->object.oid.hash[0] != i)
 798                                 break;
 799                         display_progress(ctx->progress, ++ctx->progress_cnt);
 800                         count++;
 801                         list++;
 802                 }
 803
 804                 hashwrite_be32(f, count);
 805         }
 806 }
 807
 808 static void write_graph_chunk_oids(struct hashfile *f, int hash_len,
 809                                    struct write_commit_graph_context *ctx)
 810 {
 811         struct commit **list = ctx->commits.list;
 812         int count;
 813         for (count = 0; count < ctx->commits.nr; count++, list++) {
 814                 display_progress(ctx->progress, ++ctx->progress_cnt);
 815                 hashwrite(f, (*list)->object.oid.hash, (int)hash_len);
 816         }
 817 }
 818
 819 static const unsigned char *commit_to_sha1(size_t index, void *table)
 820 {
 821         struct commit **commits = table;
 822         return commits[index]->object.oid.hash;
 823 }
 824
 825 static void write_graph_chunk_data(struct hashfile *f, int hash_len,
 826                                    struct write_commit_graph_context *ctx)
 827 {
 828         struct commit **list = ctx->commits.list;
 829         struct commit **last = ctx->commits.list + ctx->commits.nr;
 830         uint32_t num_extra_edges = 0;
 831
 832         while (list < last) {
 833                 struct commit_list *parent;
 834                 int edge_value;
 835                 uint32_t packedDate[2];
 836                 display_progress(ctx->progress, ++ctx->progress_cnt);
 837
 838                 parse_commit_no_graph(*list);
 839                 hashwrite(f, get_commit_tree_oid(*list)->hash, hash_len);
 840
 841                 parent = (*list)->parents;
 842
 843                 if (!parent)
 844                         edge_value = GRAPH_PARENT_NONE;
 845                 else {
 846                         edge_value = sha1_pos(parent->item->object.oid.hash,
 847                                               ctx->commits.list,
 848                                               ctx->commits.nr,
 849                                               commit_to_sha1);
 850
 851                         if (edge_value >= 0)
 852                                 edge_value += ctx->new_num_commits_in_base;
 853                         else {
 854                                 uint32_t pos;
 855                                 if (find_commit_in_graph(parent->item,
 856                                                          ctx->new_base_graph,
 857                                                          &pos))
 858                                         edge_value = pos;
 859                         }
 860
 861                         if (edge_value < 0)
 862                                 BUG("missing parent %s for commit %s",
 863                                     oid_to_hex(&parent->item->object.oid),
 864                                     oid_to_hex(&(*list)->object.oid));
 865                 }
 866
 867                 hashwrite_be32(f, edge_value);
 868
 869                 if (parent)
 870                         parent = parent->next;
 871
 872                 if (!parent)
 873                         edge_value = GRAPH_PARENT_NONE;
 874                 else if (parent->next)
 875                         edge_value = GRAPH_EXTRA_EDGES_NEEDED | num_extra_edges;
 876                 else {
 877                         edge_value = sha1_pos(parent->item->object.oid.hash,
 878                                               ctx->commits.list,
 879                                               ctx->commits.nr,
 880                                               commit_to_sha1);
 881
 882                         if (edge_value >= 0)
 883                                 edge_value += ctx->new_num_commits_in_base;
 884                         else {
 885                                 uint32_t pos;
 886                                 if (find_commit_in_graph(parent->item,
 887                                                          ctx->new_base_graph,
 888                                                          &pos))
 889                                         edge_value = pos;
 890                         }
 891
 892                         if (edge_value < 0)
 893                                 BUG("missing parent %s for commit %s",
 894                                     oid_to_hex(&parent->item->object.oid),
 895                                     oid_to_hex(&(*list)->object.oid));
 896                 }
 897
 898                 hashwrite_be32(f, edge_value);
 899
 900                 if (edge_value & GRAPH_EXTRA_EDGES_NEEDED) {
 901                         do {
 902                                 num_extra_edges++;
 903                                 parent = parent->next;
 904                         } while (parent);
 905                 }
 906
 907                 if (sizeof((*list)->date) > 4)
 908                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
 909                 else
 910                         packedDate[0] = 0;
 911
 912                 packedDate[0] |= htonl((*list)->generation << 2);
 913
 914                 packedDate[1] = htonl((*list)->date);
 915                 hashwrite(f, packedDate, 8);
 916
 917                 list++;
 918         }
 919 }
 920
 921 static void write_graph_chunk_extra_edges(struct hashfile *f,
 922                                           struct write_commit_graph_context *ctx)
 923 {
 924         struct commit **list = ctx->commits.list;
 925         struct commit **last = ctx->commits.list + ctx->commits.nr;
 926         struct commit_list *parent;
 927
 928         while (list < last) {
 929                 int num_parents = 0;
 930
 931                 display_progress(ctx->progress, ++ctx->progress_cnt);
 932
 933                 for (parent = (*list)->parents; num_parents < 3 && parent;
 934                      parent = parent->next)
 935                         num_parents++;
 936
 937                 if (num_parents <= 2) {
 938                         list++;
 939                         continue;
 940                 }
 941
 942                 /* Since num_parents > 2, this initializer is safe. */
 943                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
 944                         int edge_value = sha1_pos(parent->item->object.oid.hash,
 945                                                   ctx->commits.list,
 946                                                   ctx->commits.nr,
 947                                                   commit_to_sha1);
 948
 949                         if (edge_value >= 0)
 950                                 edge_value += ctx->new_num_commits_in_base;
 951                         else {
 952                                 uint32_t pos;
 953                                 if (find_commit_in_graph(parent->item,
 954                                                          ctx->new_base_graph,
 955                                                          &pos))
 956                                         edge_value = pos;
 957                         }
 958
 959                         if (edge_value < 0)
 960                                 BUG("missing parent %s for commit %s",
 961                                     oid_to_hex(&parent->item->object.oid),
 962                                     oid_to_hex(&(*list)->object.oid));
 963                         else if (!parent->next)
 964                                 edge_value |= GRAPH_LAST_EDGE;
 965
 966                         hashwrite_be32(f, edge_value);
 967                 }
 968
 969                 list++;
 970         }
 971 }
 972
 973 static int oid_compare(const void *_a, const void *_b)
 974 {
 975         const struct object_id *a = (const struct object_id *)_a;
 976         const struct object_id *b = (const struct object_id *)_b;
 977         return oidcmp(a, b);
 978 }
 979
 980 static int add_packed_commits(const struct object_id *oid,
 981                               struct packed_git *pack,
 982                               uint32_t pos,
 983                               void *data)
 984 {
 985         struct write_commit_graph_context *ctx = (struct write_commit_graph_context*)data;
 986         enum object_type type;
 987         off_t offset = nth_packed_object_offset(pack, pos);
 988         struct object_info oi = OBJECT_INFO_INIT;
 989
 990         if (ctx->progress)
 991                 display_progress(ctx->progress, ++ctx->progress_done);
 992
 993         oi.typep = &type;
 994         if (packed_object_info(ctx->r, pack, offset, &oi) < 0)
 995                 die(_("unable to get type of object %s"), oid_to_hex(oid));
 996
 997         if (type != OBJ_COMMIT)
 998                 return 0;
 999
1000         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1001         oidcpy(&(ctx->oids.list[ctx->oids.nr]), oid);
1002         ctx->oids.nr++;
1003
1004         return 0;
1005 }
1006
1007 static void add_missing_parents(struct write_commit_graph_context *ctx, struct commit *commit)
1008 {
1009         struct commit_list *parent;
1010         for (parent = commit->parents; parent; parent = parent->next) {
1011                 if (!(parent->item->object.flags & UNINTERESTING)) {
1012                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1013                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(parent->item->object.oid));
1014                         ctx->oids.nr++;
1015                         parent->item->object.flags |= UNINTERESTING;
1016                 }
1017         }
1018 }
1019
1020 static void close_reachable(struct write_commit_graph_context *ctx)
1021 {
1022         int i;
1023         struct commit *commit;
1024
1025         if (ctx->report_progress)
1026                 ctx->progress = start_delayed_progress(
1027                                         _("Loading known commits in commit graph"),
1028                                         ctx->oids.nr);
1029         for (i = 0; i < ctx->oids.nr; i++) {
1030                 display_progress(ctx->progress, i + 1);
1031                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1032                 if (commit)
1033                         commit->object.flags |= UNINTERESTING;
1034         }
1035         stop_progress(&ctx->progress);
1036
1037         /*
1038          * As this loop runs, ctx->oids.nr may grow, but not more
1039          * than the number of missing commits in the reachable
1040          * closure.
1041          */
1042         if (ctx->report_progress)
1043                 ctx->progress = start_delayed_progress(
1044                                         _("Expanding reachable commits in commit graph"),
1045                                         ctx->oids.nr);
1046         for (i = 0; i < ctx->oids.nr; i++) {
1047                 display_progress(ctx->progress, i + 1);
1048                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1049
1050                 if (!commit)
1051                         continue;
1052                 if (ctx->split) {
1053                         if (!parse_commit(commit) &&
1054                             commit->graph_pos == COMMIT_NOT_FROM_GRAPH)
1055                                 add_missing_parents(ctx, commit);
1056                 } else if (!parse_commit_no_graph(commit))
1057                         add_missing_parents(ctx, commit);
1058         }
1059         stop_progress(&ctx->progress);
1060
1061         if (ctx->report_progress)
1062                 ctx->progress = start_delayed_progress(
1063                                         _("Clearing commit marks in commit graph"),
1064                                         ctx->oids.nr);
1065         for (i = 0; i < ctx->oids.nr; i++) {
1066                 display_progress(ctx->progress, i + 1);
1067                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1068
1069                 if (commit)
1070                         commit->object.flags &= ~UNINTERESTING;
1071         }
1072         stop_progress(&ctx->progress);
1073 }
1074
1075 static void compute_generation_numbers(struct write_commit_graph_context *ctx)
1076 {
1077         int i;
1078         struct commit_list *list = NULL;
1079
1080         if (ctx->report_progress)
1081                 ctx->progress = start_progress(
1082                                         _("Computing commit graph generation numbers"),
1083                                         ctx->commits.nr);
1084         for (i = 0; i < ctx->commits.nr; i++) {
1085                 display_progress(ctx->progress, i + 1);
1086                 if (ctx->commits.list[i]->generation != GENERATION_NUMBER_INFINITY &&
1087                     ctx->commits.list[i]->generation != GENERATION_NUMBER_ZERO)
1088                         continue;
1089
1090                 commit_list_insert(ctx->commits.list[i], &list);
1091                 while (list) {
1092                         struct commit *current = list->item;
1093                         struct commit_list *parent;
1094                         int all_parents_computed = 1;
1095                         uint32_t max_generation = 0;
1096
1097                         for (parent = current->parents; parent; parent = parent->next) {
1098                                 if (parent->item->generation == GENERATION_NUMBER_INFINITY ||
1099                                     parent->item->generation == GENERATION_NUMBER_ZERO) {
1100                                         all_parents_computed = 0;
1101                                         commit_list_insert(parent->item, &list);
1102                                         break;
1103                                 } else if (parent->item->generation > max_generation) {
1104                                         max_generation = parent->item->generation;
1105                                 }
1106                         }
1107
1108                         if (all_parents_computed) {
1109                                 current->generation = max_generation + 1;
1110                                 pop_commit(&list);
1111
1112                                 if (current->generation > GENERATION_NUMBER_MAX)
1113                                         current->generation = GENERATION_NUMBER_MAX;
1114                         }
1115                 }
1116         }
1117         stop_progress(&ctx->progress);
1118 }
1119
1120 static int add_ref_to_list(const char *refname,
1121                            const struct object_id *oid,
1122                            int flags, void *cb_data)
1123 {
1124         struct string_list *list = (struct string_list *)cb_data;
1125
1126         string_list_append(list, oid_to_hex(oid));
1127         return 0;
1128 }
1129
1130 int write_commit_graph_reachable(const char *obj_dir, unsigned int flags,
1131                                  const struct split_commit_graph_opts *split_opts)
1132 {
1133         struct string_list list = STRING_LIST_INIT_DUP;
1134         int result;
1135
1136         for_each_ref(add_ref_to_list, &list);
1137         result = write_commit_graph(obj_dir, NULL, &list,
1138                                     flags, split_opts);
1139
1140         string_list_clear(&list, 0);
1141         return result;
1142 }
1143
1144 static int fill_oids_from_packs(struct write_commit_graph_context *ctx,
1145                                 struct string_list *pack_indexes)
1146 {
1147         uint32_t i;
1148         struct strbuf progress_title = STRBUF_INIT;
1149         struct strbuf packname = STRBUF_INIT;
1150         int dirlen;
1151
1152         strbuf_addf(&packname, "%s/pack/", ctx->obj_dir);
1153         dirlen = packname.len;
1154         if (ctx->report_progress) {
1155                 strbuf_addf(&progress_title,
1156                             Q_("Finding commits for commit graph in %d pack",
1157                                "Finding commits for commit graph in %d packs",
1158                                pack_indexes->nr),
1159                             pack_indexes->nr);
1160                 ctx->progress = start_delayed_progress(progress_title.buf, 0);
1161                 ctx->progress_done = 0;
1162         }
1163         for (i = 0; i < pack_indexes->nr; i++) {
1164                 struct packed_git *p;
1165                 strbuf_setlen(&packname, dirlen);
1166                 strbuf_addstr(&packname, pack_indexes->items[i].string);
1167                 p = add_packed_git(packname.buf, packname.len, 1);
1168                 if (!p) {
1169                         error(_("error adding pack %s"), packname.buf);
1170                         return -1;
1171                 }
1172                 if (open_pack_index(p)) {
1173                         error(_("error opening index for %s"), packname.buf);
1174                         return -1;
1175                 }
1176                 for_each_object_in_pack(p, add_packed_commits, ctx,
1177                                         FOR_EACH_OBJECT_PACK_ORDER);
1178                 close_pack(p);
1179                 free(p);
1180         }
1181
1182         stop_progress(&ctx->progress);
1183         strbuf_release(&progress_title);
1184         strbuf_release(&packname);
1185
1186         return 0;
1187 }
1188
1189 static void fill_oids_from_commit_hex(struct write_commit_graph_context *ctx,
1190                                       struct string_list *commit_hex)
1191 {
1192         uint32_t i;
1193         struct strbuf progress_title = STRBUF_INIT;
1194
1195         if (ctx->report_progress) {
1196                 strbuf_addf(&progress_title,
1197                             Q_("Finding commits for commit graph from %d ref",
1198                                "Finding commits for commit graph from %d refs",
1199                                commit_hex->nr),
1200                             commit_hex->nr);
1201                 ctx->progress = start_delayed_progress(
1202                                         progress_title.buf,
1203                                         commit_hex->nr);
1204         }
1205         for (i = 0; i < commit_hex->nr; i++) {
1206                 const char *end;
1207                 struct object_id oid;
1208                 struct commit *result;
1209
1210                 display_progress(ctx->progress, i + 1);
1211                 if (commit_hex->items[i].string &&
1212                     parse_oid_hex(commit_hex->items[i].string, &oid, &end))
1213                         continue;
1214
1215                 result = lookup_commit_reference_gently(ctx->r, &oid, 1);
1216
1217                 if (result) {
1218                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1219                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(result->object.oid));
1220                         ctx->oids.nr++;
1221                 }
1222         }
1223         stop_progress(&ctx->progress);
1224         strbuf_release(&progress_title);
1225 }
1226
1227 static void fill_oids_from_all_packs(struct write_commit_graph_context *ctx)
1228 {
1229         if (ctx->report_progress)
1230                 ctx->progress = start_delayed_progress(
1231                         _("Finding commits for commit graph among packed objects"),
1232                         ctx->approx_nr_objects);
1233         for_each_packed_object(add_packed_commits, ctx,
1234                                FOR_EACH_OBJECT_PACK_ORDER);
1235         if (ctx->progress_done < ctx->approx_nr_objects)
1236                 display_progress(ctx->progress, ctx->approx_nr_objects);
1237         stop_progress(&ctx->progress);
1238 }
1239
1240 static uint32_t count_distinct_commits(struct write_commit_graph_context *ctx)
1241 {
1242         uint32_t i, count_distinct = 1;
1243
1244         if (ctx->report_progress)
1245                 ctx->progress = start_delayed_progress(
1246                         _("Counting distinct commits in commit graph"),
1247                         ctx->oids.nr);
1248         display_progress(ctx->progress, 0); /* TODO: Measure QSORT() progress */
1249         QSORT(ctx->oids.list, ctx->oids.nr, oid_compare);
1250
1251         for (i = 1; i < ctx->oids.nr; i++) {
1252                 display_progress(ctx->progress, i + 1);
1253                 if (!oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i])) {
1254                         if (ctx->split) {
1255                                 struct commit *c = lookup_commit(ctx->r, &ctx->oids.list[i]);
1256
1257                                 if (!c || c->graph_pos != COMMIT_NOT_FROM_GRAPH)
1258                                         continue;
1259                         }
1260
1261                         count_distinct++;
1262                 }
1263         }
1264         stop_progress(&ctx->progress);
1265
1266         return count_distinct;
1267 }
1268
1269 static void copy_oids_to_commits(struct write_commit_graph_context *ctx)
1270 {
1271         uint32_t i;
1272         struct commit_list *parent;
1273
1274         ctx->num_extra_edges = 0;
1275         if (ctx->report_progress)
1276                 ctx->progress = start_delayed_progress(
1277                         _("Finding extra edges in commit graph"),
1278                         ctx->oids.nr);
1279         for (i = 0; i < ctx->oids.nr; i++) {
1280                 int num_parents = 0;
1281                 display_progress(ctx->progress, i + 1);
1282                 if (i > 0 && oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i]))
1283                         continue;
1284
1285                 ALLOC_GROW(ctx->commits.list, ctx->commits.nr + 1, ctx->commits.alloc);
1286                 ctx->commits.list[ctx->commits.nr] = lookup_commit(ctx->r, &ctx->oids.list[i]);
1287
1288                 if (ctx->split &&
1289                     ctx->commits.list[ctx->commits.nr]->graph_pos != COMMIT_NOT_FROM_GRAPH)
1290                         continue;
1291
1292                 parse_commit_no_graph(ctx->commits.list[ctx->commits.nr]);
1293
1294                 for (parent = ctx->commits.list[ctx->commits.nr]->parents;
1295                      parent; parent = parent->next)
1296                         num_parents++;
1297
1298                 if (num_parents > 2)
1299                         ctx->num_extra_edges += num_parents - 1;
1300
1301                 ctx->commits.nr++;
1302         }
1303         stop_progress(&ctx->progress);
1304 }
1305
1306 static int write_graph_chunk_base_1(struct hashfile *f,
1307                                     struct commit_graph *g)
1308 {
1309         int num = 0;
1310
1311         if (!g)
1312                 return 0;
1313
1314         num = write_graph_chunk_base_1(f, g->base_graph);
1315         hashwrite(f, g->oid.hash, the_hash_algo->rawsz);
1316         return num + 1;
1317 }
1318
1319 static int write_graph_chunk_base(struct hashfile *f,
1320                                   struct write_commit_graph_context *ctx)
1321 {
1322         int num = write_graph_chunk_base_1(f, ctx->new_base_graph);
1323
1324         if (num != ctx->num_commit_graphs_after - 1) {
1325                 error(_("failed to write correct number of base graph ids"));
1326                 return -1;
1327         }
1328
1329         return 0;
1330 }
1331
1332 static int write_commit_graph_file(struct write_commit_graph_context *ctx)
1333 {
1334         uint32_t i;
1335         int fd;
1336         struct hashfile *f;
1337         struct lock_file lk = LOCK_INIT;
1338         uint32_t chunk_ids[6];
1339         uint64_t chunk_offsets[6];
1340         const unsigned hashsz = the_hash_algo->rawsz;
1341         struct strbuf progress_title = STRBUF_INIT;
1342         int num_chunks = 3;
1343         struct object_id file_hash;
1344
1345         if (ctx->split) {
1346                 struct strbuf tmp_file = STRBUF_INIT;
1347
1348                 strbuf_addf(&tmp_file,
1349                             "%s/info/commit-graphs/tmp_graph_XXXXXX",
1350                             ctx->obj_dir);
1351                 ctx->graph_name = strbuf_detach(&tmp_file, NULL);
1352         } else {
1353                 ctx->graph_name = get_commit_graph_filename(ctx->obj_dir);
1354         }
1355
1356         if (safe_create_leading_directories(ctx->graph_name)) {
1357                 UNLEAK(ctx->graph_name);
1358                 error(_("unable to create leading directories of %s"),
1359                         ctx->graph_name);
1360                 return -1;
1361         }
1362
1363         if (ctx->split) {
1364                 char *lock_name = get_chain_filename(ctx->obj_dir);
1365
1366                 hold_lock_file_for_update(&lk, lock_name, LOCK_DIE_ON_ERROR);
1367
1368                 fd = git_mkstemp_mode(ctx->graph_name, 0444);
1369                 if (fd < 0) {
1370                         error(_("unable to create '%s'"), ctx->graph_name);
1371                         return -1;
1372                 }
1373
1374                 f = hashfd(fd, ctx->graph_name);
1375         } else {
1376                 hold_lock_file_for_update(&lk, ctx->graph_name, LOCK_DIE_ON_ERROR);
1377                 fd = lk.tempfile->fd;
1378                 f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
1379         }
1380
1381         chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
1382         chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
1383         chunk_ids[2] = GRAPH_CHUNKID_DATA;
1384         if (ctx->num_extra_edges) {
1385                 chunk_ids[num_chunks] = GRAPH_CHUNKID_EXTRAEDGES;
1386                 num_chunks++;
1387         }
1388         if (ctx->num_commit_graphs_after > 1) {
1389                 chunk_ids[num_chunks] = GRAPH_CHUNKID_BASE;
1390                 num_chunks++;
1391         }
1392
1393         chunk_ids[num_chunks] = 0;
1394
1395         chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
1396         chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
1397         chunk_offsets[2] = chunk_offsets[1] + hashsz * ctx->commits.nr;
1398         chunk_offsets[3] = chunk_offsets[2] + (hashsz + 16) * ctx->commits.nr;
1399
1400         num_chunks = 3;
1401         if (ctx->num_extra_edges) {
1402                 chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
1403                                                 4 * ctx->num_extra_edges;
1404                 num_chunks++;
1405         }
1406         if (ctx->num_commit_graphs_after > 1) {
1407                 chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
1408                                                 hashsz * (ctx->num_commit_graphs_after - 1);
1409                 num_chunks++;
1410         }
1411
1412         hashwrite_be32(f, GRAPH_SIGNATURE);
1413
1414         hashwrite_u8(f, GRAPH_VERSION);
1415         hashwrite_u8(f, oid_version());
1416         hashwrite_u8(f, num_chunks);
1417         hashwrite_u8(f, ctx->num_commit_graphs_after - 1);
1418
1419         for (i = 0; i <= num_chunks; i++) {
1420                 uint32_t chunk_write[3];
1421
1422                 chunk_write[0] = htonl(chunk_ids[i]);
1423                 chunk_write[1] = htonl(chunk_offsets[i] >> 32);
1424                 chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
1425                 hashwrite(f, chunk_write, 12);
1426         }
1427
1428         if (ctx->report_progress) {
1429                 strbuf_addf(&progress_title,
1430                             Q_("Writing out commit graph in %d pass",
1431                                "Writing out commit graph in %d passes",
1432                                num_chunks),
1433                             num_chunks);
1434                 ctx->progress = start_delayed_progress(
1435                         progress_title.buf,
1436                         num_chunks * ctx->commits.nr);
1437         }
1438         write_graph_chunk_fanout(f, ctx);
1439         write_graph_chunk_oids(f, hashsz, ctx);
1440         write_graph_chunk_data(f, hashsz, ctx);
1441         if (ctx->num_extra_edges)
1442                 write_graph_chunk_extra_edges(f, ctx);
1443         if (ctx->num_commit_graphs_after > 1 &&
1444             write_graph_chunk_base(f, ctx)) {
1445                 return -1;
1446         }
1447         stop_progress(&ctx->progress);
1448         strbuf_release(&progress_title);
1449
1450         if (ctx->split && ctx->base_graph_name && ctx->num_commit_graphs_after > 1) {
1451                 char *new_base_hash = xstrdup(oid_to_hex(&ctx->new_base_graph->oid));
1452                 char *new_base_name = get_split_graph_filename(ctx->new_base_graph->obj_dir, new_base_hash);
1453
1454                 free(ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2]);
1455                 free(ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2]);
1456                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2] = new_base_name;
1457                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2] = new_base_hash;
1458         }
1459
1460         close_commit_graph(ctx->r->objects);
1461         finalize_hashfile(f, file_hash.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
1462
1463         if (ctx->split) {
1464                 FILE *chainf = fdopen_lock_file(&lk, "w");
1465                 char *final_graph_name;
1466                 int result;
1467
1468                 close(fd);
1469
1470                 if (!chainf) {
1471                         error(_("unable to open commit-graph chain file"));
1472                         return -1;
1473                 }
1474
1475                 if (ctx->base_graph_name) {
1476                         const char *dest = ctx->commit_graph_filenames_after[
1477                                                 ctx->num_commit_graphs_after - 2];
1478
1479                         if (strcmp(ctx->base_graph_name, dest)) {
1480                                 result = rename(ctx->base_graph_name, dest);
1481
1482                                 if (result) {
1483                                         error(_("failed to rename base commit-graph file"));
1484                                         return -1;
1485                                 }
1486                         }
1487                 } else {
1488                         char *graph_name = get_commit_graph_filename(ctx->obj_dir);
1489                         unlink(graph_name);
1490                 }
1491
1492                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(oid_to_hex(&file_hash));
1493                 final_graph_name = get_split_graph_filename(ctx->obj_dir,
1494                                         ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
1495                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1] = final_graph_name;
1496
1497                 result = rename(ctx->graph_name, final_graph_name);
1498
1499                 for (i = 0; i < ctx->num_commit_graphs_after; i++)
1500                         fprintf(lk.tempfile->fp, "%s\n", ctx->commit_graph_hash_after[i]);
1501
1502                 if (result) {
1503                         error(_("failed to rename temporary commit-graph file"));
1504                         return -1;
1505                 }
1506         }
1507
1508         commit_lock_file(&lk);
1509
1510         return 0;
1511 }
1512
1513 static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
1514 {
1515         struct commit_graph *g = ctx->r->objects->commit_graph;
1516         uint32_t num_commits = ctx->commits.nr;
1517         uint32_t i;
1518
1519         int max_commits = 0;
1520         int size_mult = 2;
1521
1522         if (ctx->split_opts) {
1523                 max_commits = ctx->split_opts->max_commits;
1524                 size_mult = ctx->split_opts->size_multiple;
1525         }
1526
1527         g = ctx->r->objects->commit_graph;
1528         ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1;
1529
1530         while (g && (g->num_commits <= size_mult * num_commits ||
1531                     (max_commits && num_commits > max_commits))) {
1532                 if (strcmp(g->obj_dir, ctx->obj_dir))
1533                         break;
1534
1535                 num_commits += g->num_commits;
1536                 g = g->base_graph;
1537
1538                 ctx->num_commit_graphs_after--;
1539         }
1540
1541         ctx->new_base_graph = g;
1542
1543         if (ctx->num_commit_graphs_after == 2) {
1544                 char *old_graph_name = get_commit_graph_filename(g->obj_dir);
1545
1546                 if (!strcmp(g->filename, old_graph_name) &&
1547                     strcmp(g->obj_dir, ctx->obj_dir)) {
1548                         ctx->num_commit_graphs_after = 1;
1549                         ctx->new_base_graph = NULL;
1550                 }
1551
1552                 free(old_graph_name);
1553         }
1554
1555         ALLOC_ARRAY(ctx->commit_graph_filenames_after, ctx->num_commit_graphs_after);
1556         ALLOC_ARRAY(ctx->commit_graph_hash_after, ctx->num_commit_graphs_after);
1557
1558         for (i = 0; i < ctx->num_commit_graphs_after &&
1559                     i < ctx->num_commit_graphs_before; i++)
1560                 ctx->commit_graph_filenames_after[i] = xstrdup(ctx->commit_graph_filenames_before[i]);
1561
1562         i = ctx->num_commit_graphs_before - 1;
1563         g = ctx->r->objects->commit_graph;
1564
1565         while (g) {
1566                 if (i < ctx->num_commit_graphs_after)
1567                         ctx->commit_graph_hash_after[i] = xstrdup(oid_to_hex(&g->oid));
1568
1569                 i--;
1570                 g = g->base_graph;
1571         }
1572 }
1573
1574 static void merge_commit_graph(struct write_commit_graph_context *ctx,
1575                                struct commit_graph *g)
1576 {
1577         uint32_t i;
1578         uint32_t offset = g->num_commits_in_base;
1579
1580         ALLOC_GROW(ctx->commits.list, ctx->commits.nr + g->num_commits, ctx->commits.alloc);
1581
1582         for (i = 0; i < g->num_commits; i++) {
1583                 struct object_id oid;
1584                 struct commit *result;
1585
1586                 display_progress(ctx->progress, i + 1);
1587
1588                 load_oid_from_graph(g, i + offset, &oid);
1589
1590                 /* only add commits if they still exist in the repo */
1591                 result = lookup_commit_reference_gently(ctx->r, &oid, 1);
1592
1593                 if (result) {
1594                         ctx->commits.list[ctx->commits.nr] = result;
1595                         ctx->commits.nr++;
1596                 }
1597         }
1598 }
1599
1600 static int commit_compare(const void *_a, const void *_b)
1601 {
1602         const struct commit *a = *(const struct commit **)_a;
1603         const struct commit *b = *(const struct commit **)_b;
1604         return oidcmp(&a->object.oid, &b->object.oid);
1605 }
1606
1607 static void sort_and_scan_merged_commits(struct write_commit_graph_context *ctx)
1608 {
1609         uint32_t i, num_parents;
1610         struct commit_list *parent;
1611
1612         if (ctx->report_progress)
1613                 ctx->progress = start_delayed_progress(
1614                                         _("Scanning merged commits"),
1615                                         ctx->commits.nr);
1616
1617         QSORT(ctx->commits.list, ctx->commits.nr, commit_compare);
1618
1619         ctx->num_extra_edges = 0;
1620         for (i = 0; i < ctx->commits.nr; i++) {
1621                 display_progress(ctx->progress, i);
1622
1623                 if (i && oideq(&ctx->commits.list[i - 1]->object.oid,
1624                           &ctx->commits.list[i]->object.oid)) {
1625                         die(_("unexpected duplicate commit id %s"),
1626                             oid_to_hex(&ctx->commits.list[i]->object.oid));
1627                 } else {
1628                         num_parents = 0;
1629                         for (parent = ctx->commits.list[i]->parents; parent; parent = parent->next)
1630                                 num_parents++;
1631
1632                         if (num_parents > 2)
1633                                 ctx->num_extra_edges += num_parents - 2;
1634                 }
1635         }
1636
1637         stop_progress(&ctx->progress);
1638 }
1639
1640 static void merge_commit_graphs(struct write_commit_graph_context *ctx)
1641 {
1642         struct commit_graph *g = ctx->r->objects->commit_graph;
1643         uint32_t current_graph_number = ctx->num_commit_graphs_before;
1644         struct strbuf progress_title = STRBUF_INIT;
1645
1646         while (g && current_graph_number >= ctx->num_commit_graphs_after) {
1647                 current_graph_number--;
1648
1649                 if (ctx->report_progress) {
1650                         strbuf_addstr(&progress_title, _("Merging commit-graph"));
1651                         ctx->progress = start_delayed_progress(progress_title.buf, 0);
1652                 }
1653
1654                 merge_commit_graph(ctx, g);
1655                 stop_progress(&ctx->progress);
1656                 strbuf_release(&progress_title);
1657
1658                 g = g->base_graph;
1659         }
1660
1661         if (g) {
1662                 ctx->new_base_graph = g;
1663                 ctx->new_num_commits_in_base = g->num_commits + g->num_commits_in_base;
1664         }
1665
1666         if (ctx->new_base_graph)
1667                 ctx->base_graph_name = xstrdup(ctx->new_base_graph->filename);
1668
1669         sort_and_scan_merged_commits(ctx);
1670 }
1671
1672 static void mark_commit_graphs(struct write_commit_graph_context *ctx)
1673 {
1674         uint32_t i;
1675         time_t now = time(NULL);
1676
1677         for (i = ctx->num_commit_graphs_after - 1; i < ctx->num_commit_graphs_before; i++) {
1678                 struct stat st;
1679                 struct utimbuf updated_time;
1680
1681                 stat(ctx->commit_graph_filenames_before[i], &st);
1682
1683                 updated_time.actime = st.st_atime;
1684                 updated_time.modtime = now;
1685                 utime(ctx->commit_graph_filenames_before[i], &updated_time);
1686         }
1687 }
1688
1689 static void expire_commit_graphs(struct write_commit_graph_context *ctx)
1690 {
1691         struct strbuf path = STRBUF_INIT;
1692         DIR *dir;
1693         struct dirent *de;
1694         size_t dirnamelen;
1695         timestamp_t expire_time = time(NULL);
1696
1697         if (ctx->split_opts && ctx->split_opts->expire_time)
1698                 expire_time -= ctx->split_opts->expire_time;
1699         if (!ctx->split) {
1700                 char *chain_file_name = get_chain_filename(ctx->obj_dir);
1701                 unlink(chain_file_name);
1702                 free(chain_file_name);
1703                 ctx->num_commit_graphs_after = 0;
1704         }
1705
1706         strbuf_addstr(&path, ctx->obj_dir);
1707         strbuf_addstr(&path, "/info/commit-graphs");
1708         dir = opendir(path.buf);
1709
1710         if (!dir)
1711                 goto out;
1712
1713         strbuf_addch(&path, '/');
1714         dirnamelen = path.len;
1715         while ((de = readdir(dir)) != NULL) {
1716                 struct stat st;
1717                 uint32_t i, found = 0;
1718
1719                 strbuf_setlen(&path, dirnamelen);
1720                 strbuf_addstr(&path, de->d_name);
1721
1722                 stat(path.buf, &st);
1723
1724                 if (st.st_mtime > expire_time)
1725                         continue;
1726                 if (path.len < 6 || strcmp(path.buf + path.len - 6, ".graph"))
1727                         continue;
1728
1729                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
1730                         if (!strcmp(ctx->commit_graph_filenames_after[i],
1731                                     path.buf)) {
1732                                 found = 1;
1733                                 break;
1734                         }
1735                 }
1736
1737                 if (!found)
1738                         unlink(path.buf);
1739         }
1740
1741 out:
1742         strbuf_release(&path);
1743 }
1744
1745 int write_commit_graph(const char *obj_dir,
1746                        struct string_list *pack_indexes,
1747                        struct string_list *commit_hex,
1748                        unsigned int flags,
1749                        const struct split_commit_graph_opts *split_opts)
1750 {
1751         struct write_commit_graph_context *ctx;
1752         uint32_t i, count_distinct = 0;
1753         size_t len;
1754         int res = 0;
1755
1756         if (!commit_graph_compatible(the_repository))
1757                 return 0;
1758
1759         ctx = xcalloc(1, sizeof(struct write_commit_graph_context));
1760         ctx->r = the_repository;
1761
1762         /* normalize object dir with no trailing slash */
1763         ctx->obj_dir = xmallocz(strlen(obj_dir) + 1);
1764         normalize_path_copy(ctx->obj_dir, obj_dir);
1765         len = strlen(ctx->obj_dir);
1766         if (len && ctx->obj_dir[len - 1] == '/')
1767                 ctx->obj_dir[len - 1] = 0;
1768
1769         ctx->append = flags & COMMIT_GRAPH_APPEND ? 1 : 0;
1770         ctx->report_progress = flags & COMMIT_GRAPH_PROGRESS ? 1 : 0;
1771         ctx->split = flags & COMMIT_GRAPH_SPLIT ? 1 : 0;
1772         ctx->split_opts = split_opts;
1773
1774         if (ctx->split) {
1775                 struct commit_graph *g;
1776                 prepare_commit_graph(ctx->r);
1777
1778                 g = ctx->r->objects->commit_graph;
1779
1780                 while (g) {
1781                         ctx->num_commit_graphs_before++;
1782                         g = g->base_graph;
1783                 }
1784
1785                 if (ctx->num_commit_graphs_before) {
1786                         ALLOC_ARRAY(ctx->commit_graph_filenames_before, ctx->num_commit_graphs_before);
1787                         i = ctx->num_commit_graphs_before;
1788                         g = ctx->r->objects->commit_graph;
1789
1790                         while (g) {
1791                                 ctx->commit_graph_filenames_before[--i] = xstrdup(g->filename);
1792                                 g = g->base_graph;
1793                         }
1794                 }
1795         }
1796
1797         ctx->approx_nr_objects = approximate_object_count();
1798         ctx->oids.alloc = ctx->approx_nr_objects / 32;
1799
1800         if (ctx->split && split_opts && ctx->oids.alloc > split_opts->max_commits)
1801                 ctx->oids.alloc = split_opts->max_commits;
1802
1803         if (ctx->append) {
1804                 prepare_commit_graph_one(ctx->r, ctx->obj_dir);
1805                 if (ctx->r->objects->commit_graph)
1806                         ctx->oids.alloc += ctx->r->objects->commit_graph->num_commits;
1807         }
1808
1809         if (ctx->oids.alloc < 1024)
1810                 ctx->oids.alloc = 1024;
1811         ALLOC_ARRAY(ctx->oids.list, ctx->oids.alloc);
1812
1813         if (ctx->append && ctx->r->objects->commit_graph) {
1814                 struct commit_graph *g = ctx->r->objects->commit_graph;
1815                 for (i = 0; i < g->num_commits; i++) {
1816                         const unsigned char *hash = g->chunk_oid_lookup + g->hash_len * i;
1817                         hashcpy(ctx->oids.list[ctx->oids.nr++].hash, hash);
1818                 }
1819         }
1820
1821         if (pack_indexes) {
1822                 if ((res = fill_oids_from_packs(ctx, pack_indexes)))
1823                         goto cleanup;
1824         }
1825
1826         if (commit_hex)
1827                 fill_oids_from_commit_hex(ctx, commit_hex);
1828
1829         if (!pack_indexes && !commit_hex)
1830                 fill_oids_from_all_packs(ctx);
1831
1832         close_reachable(ctx);
1833
1834         count_distinct = count_distinct_commits(ctx);
1835
1836         if (count_distinct >= GRAPH_EDGE_LAST_MASK) {
1837                 error(_("the commit graph format cannot write %d commits"), count_distinct);
1838                 res = -1;
1839                 goto cleanup;
1840         }
1841
1842         ctx->commits.alloc = count_distinct;
1843         ALLOC_ARRAY(ctx->commits.list, ctx->commits.alloc);
1844
1845         copy_oids_to_commits(ctx);
1846
1847         if (ctx->commits.nr >= GRAPH_EDGE_LAST_MASK) {
1848                 error(_("too many commits to write graph"));
1849                 res = -1;
1850                 goto cleanup;
1851         }
1852
1853         if (!ctx->commits.nr)
1854                 goto cleanup;
1855
1856         if (ctx->split) {
1857                 split_graph_merge_strategy(ctx);
1858
1859                 merge_commit_graphs(ctx);
1860         } else
1861                 ctx->num_commit_graphs_after = 1;
1862
1863         compute_generation_numbers(ctx);
1864
1865         res = write_commit_graph_file(ctx);
1866
1867         if (ctx->split)
1868                 mark_commit_graphs(ctx);
1869
1870         expire_commit_graphs(ctx);
1871
1872 cleanup:
1873         free(ctx->graph_name);
1874         free(ctx->commits.list);
1875         free(ctx->oids.list);
1876         free(ctx->obj_dir);
1877
1878         if (ctx->commit_graph_filenames_after) {
1879                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
1880                         free(ctx->commit_graph_filenames_after[i]);
1881                         free(ctx->commit_graph_hash_after[i]);
1882                 }
1883
1884                 for (i = 0; i < ctx->num_commit_graphs_before; i++)
1885                         free(ctx->commit_graph_filenames_before[i]);
1886
1887                 free(ctx->commit_graph_filenames_after);
1888                 free(ctx->commit_graph_filenames_before);
1889                 free(ctx->commit_graph_hash_after);
1890         }
1891
1892         free(ctx);
1893
1894         return res;
1895 }
1896
1897 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
1898 static int verify_commit_graph_error;
1899
1900 static void graph_report(const char *fmt, ...)
1901 {
1902         va_list ap;
1903
1904         verify_commit_graph_error = 1;
1905         va_start(ap, fmt);
1906         vfprintf(stderr, fmt, ap);
1907         fprintf(stderr, "\n");
1908         va_end(ap);
1909 }
1910
1911 #define GENERATION_ZERO_EXISTS 1
1912 #define GENERATION_NUMBER_EXISTS 2
1913
1914 int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
1915 {
1916         uint32_t i, cur_fanout_pos = 0;
1917         struct object_id prev_oid, cur_oid, checksum;
1918         int generation_zero = 0;
1919         struct hashfile *f;
1920         int devnull;
1921         struct progress *progress = NULL;
1922         int local_error = 0;
1923
1924         if (!g) {
1925                 graph_report("no commit-graph file loaded");
1926                 return 1;
1927         }
1928
1929         verify_commit_graph_error = verify_commit_graph_lite(g);
1930         if (verify_commit_graph_error)
1931                 return verify_commit_graph_error;
1932
1933         devnull = open("/dev/null", O_WRONLY);
1934         f = hashfd(devnull, NULL);
1935         hashwrite(f, g->data, g->data_len - g->hash_len);
1936         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
1937         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
1938                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
1939                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
1940         }
1941
1942         for (i = 0; i < g->num_commits; i++) {
1943                 struct commit *graph_commit;
1944
1945                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1946
1947                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
1948                         graph_report(_("commit-graph has incorrect OID order: %s then %s"),
1949                                      oid_to_hex(&prev_oid),
1950                                      oid_to_hex(&cur_oid));
1951
1952                 oidcpy(&prev_oid, &cur_oid);
1953
1954                 while (cur_oid.hash[0] > cur_fanout_pos) {
1955                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1956
1957                         if (i != fanout_value)
1958                                 graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
1959                                              cur_fanout_pos, fanout_value, i);
1960                         cur_fanout_pos++;
1961                 }
1962
1963                 graph_commit = lookup_commit(r, &cur_oid);
1964                 if (!parse_commit_in_graph_one(r, g, graph_commit))
1965                         graph_report(_("failed to parse commit %s from commit-graph"),
1966                                      oid_to_hex(&cur_oid));
1967         }
1968
1969         while (cur_fanout_pos < 256) {
1970                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1971
1972                 if (g->num_commits != fanout_value)
1973                         graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
1974                                      cur_fanout_pos, fanout_value, i);
1975
1976                 cur_fanout_pos++;
1977         }
1978
1979         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
1980                 return verify_commit_graph_error;
1981
1982         progress = start_progress(_("Verifying commits in commit graph"),
1983                                   g->num_commits);
1984         for (i = 0; i < g->num_commits; i++) {
1985                 struct commit *graph_commit, *odb_commit;
1986                 struct commit_list *graph_parents, *odb_parents;
1987                 uint32_t max_generation = 0;
1988
1989                 display_progress(progress, i + 1);
1990                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1991
1992                 graph_commit = lookup_commit(r, &cur_oid);
1993                 odb_commit = (struct commit *)create_object(r, cur_oid.hash, alloc_commit_node(r));
1994                 if (parse_commit_internal(odb_commit, 0, 0)) {
1995                         graph_report(_("failed to parse commit %s from object database for commit-graph"),
1996                                      oid_to_hex(&cur_oid));
1997                         continue;
1998                 }
1999
2000                 if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
2001                            get_commit_tree_oid(odb_commit)))
2002                         graph_report(_("root tree OID for commit %s in commit-graph is %s != %s"),
2003                                      oid_to_hex(&cur_oid),
2004                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
2005                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
2006
2007                 graph_parents = graph_commit->parents;
2008                 odb_parents = odb_commit->parents;
2009
2010                 while (graph_parents) {
2011                         if (odb_parents == NULL) {
2012                                 graph_report(_("commit-graph parent list for commit %s is too long"),
2013                                              oid_to_hex(&cur_oid));
2014                                 break;
2015                         }
2016
2017                         /* parse parent in case it is in a base graph */
2018                         parse_commit_in_graph_one(r, g, graph_parents->item);
2019
2020                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
2021                                 graph_report(_("commit-graph parent for %s is %s != %s"),
2022                                              oid_to_hex(&cur_oid),
2023                                              oid_to_hex(&graph_parents->item->object.oid),
2024                                              oid_to_hex(&odb_parents->item->object.oid));
2025
2026                         if (graph_parents->item->generation > max_generation)
2027                                 max_generation = graph_parents->item->generation;
2028
2029                         graph_parents = graph_parents->next;
2030                         odb_parents = odb_parents->next;
2031                 }
2032
2033                 if (odb_parents != NULL)
2034                         graph_report(_("commit-graph parent list for commit %s terminates early"),
2035                                      oid_to_hex(&cur_oid));
2036
2037                 if (!graph_commit->generation) {
2038                         if (generation_zero == GENERATION_NUMBER_EXISTS)
2039                                 graph_report(_("commit-graph has generation number zero for commit %s, but non-zero elsewhere"),
2040                                              oid_to_hex(&cur_oid));
2041                         generation_zero = GENERATION_ZERO_EXISTS;
2042                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
2043                         graph_report(_("commit-graph has non-zero generation number for commit %s, but zero elsewhere"),
2044                                      oid_to_hex(&cur_oid));
2045
2046                 if (generation_zero == GENERATION_ZERO_EXISTS)
2047                         continue;
2048
2049                 /*
2050                  * If one of our parents has generation GENERATION_NUMBER_MAX, then
2051                  * our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
2052                  * extra logic in the following condition.
2053                  */
2054                 if (max_generation == GENERATION_NUMBER_MAX)
2055                         max_generation--;
2056
2057                 if (graph_commit->generation != max_generation + 1)
2058                         graph_report(_("commit-graph generation for commit %s is %u != %u"),
2059                                      oid_to_hex(&cur_oid),
2060                                      graph_commit->generation,
2061                                      max_generation + 1);
2062
2063                 if (graph_commit->date != odb_commit->date)
2064                         graph_report(_("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime),
2065                                      oid_to_hex(&cur_oid),
2066                                      graph_commit->date,
2067                                      odb_commit->date);
2068         }
2069         stop_progress(&progress);
2070
2071         local_error = verify_commit_graph_error;
2072
2073         if (!(flags & COMMIT_GRAPH_VERIFY_SHALLOW) && g->base_graph)
2074                 local_error |= verify_commit_graph(r, g->base_graph, flags);
2075
2076         return local_error;
2077 }
2078
2079 void free_commit_graph(struct commit_graph *g)
2080 {
2081         if (!g)
2082                 return;
2083         if (g->graph_fd >= 0) {
2084                 munmap((void *)g->data, g->data_len);
2085                 g->data = NULL;
2086                 close(g->graph_fd);
2087         }
2088         free(g->filename);
2089         free(g);
2090 }