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