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