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 /* Remember to update object flag allocation in object.h */
  45 #define REACHABLE       (1u<<15)
  46
  47 char *get_commit_graph_filename(const char *obj_dir)
  48 {
  49         char *filename = xstrfmt("%s/info/commit-graph", obj_dir);
  50         char *normalized = xmalloc(strlen(filename) + 1);
  51         normalize_path_copy(normalized, filename);
  52         free(filename);
  53         return normalized;
  54 }
  55
  56 static char *get_split_graph_filename(const char *obj_dir,
  57                                       const char *oid_hex)
  58 {
  59         char *filename = xstrfmt("%s/info/commit-graphs/graph-%s.graph",
  60                                  obj_dir,
  61                                  oid_hex);
  62         char *normalized = xmalloc(strlen(filename) + 1);
  63         normalize_path_copy(normalized, filename);
  64         free(filename);
  65         return normalized;
  66 }
  67
  68 static char *get_chain_filename(const char *obj_dir)
  69 {
  70         return xstrfmt("%s/info/commit-graphs/commit-graph-chain", obj_dir);
  71 }
  72
  73 static uint8_t oid_version(void)
  74 {
  75         return 1;
  76 }
  77
  78 static struct commit_graph *alloc_commit_graph(void)
  79 {
  80         struct commit_graph *g = xcalloc(1, sizeof(*g));
  81         g->graph_fd = -1;
  82
  83         return g;
  84 }
  85
  86 extern int read_replace_refs;
  87
  88 static int commit_graph_compatible(struct repository *r)
  89 {
  90         if (!r->gitdir)
  91                 return 0;
  92
  93         if (read_replace_refs) {
  94                 prepare_replace_object(r);
  95                 if (hashmap_get_size(&r->objects->replace_map->map))
  96                         return 0;
  97         }
  98
  99         prepare_commit_graft(r);
 100         if (r->parsed_objects && r->parsed_objects->grafts_nr)
 101                 return 0;
 102         if (is_repository_shallow(r))
 103                 return 0;
 104
 105         return 1;
 106 }
 107
 108 int open_commit_graph(const char *graph_file, int *fd, struct stat *st)
 109 {
 110         *fd = git_open(graph_file);
 111         if (*fd < 0)
 112                 return 0;
 113         if (fstat(*fd, st)) {
 114                 close(*fd);
 115                 return 0;
 116         }
 117         return 1;
 118 }
 119
 120 struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st)
 121 {
 122         void *graph_map;
 123         size_t graph_size;
 124         struct commit_graph *ret;
 125
 126         graph_size = xsize_t(st->st_size);
 127
 128         if (graph_size < GRAPH_MIN_SIZE) {
 129                 close(fd);
 130                 error(_("commit-graph file is too small"));
 131                 return NULL;
 132         }
 133         graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
 134         ret = parse_commit_graph(graph_map, fd, graph_size);
 135
 136         if (!ret) {
 137                 munmap(graph_map, graph_size);
 138                 close(fd);
 139         }
 140
 141         return ret;
 142 }
 143
 144 static int verify_commit_graph_lite(struct commit_graph *g)
 145 {
 146         /*
 147          * Basic validation shared between parse_commit_graph()
 148          * which'll be called every time the graph is used, and the
 149          * much more expensive verify_commit_graph() used by
 150          * "commit-graph verify".
 151          *
 152          * There should only be very basic checks here to ensure that
 153          * we don't e.g. segfault in fill_commit_in_graph(), but
 154          * because this is a very hot codepath nothing that e.g. loops
 155          * over g->num_commits, or runs a checksum on the commit-graph
 156          * itself.
 157          */
 158         if (!g->chunk_oid_fanout) {
 159                 error("commit-graph is missing the OID Fanout chunk");
 160                 return 1;
 161         }
 162         if (!g->chunk_oid_lookup) {
 163                 error("commit-graph is missing the OID Lookup chunk");
 164                 return 1;
 165         }
 166         if (!g->chunk_commit_data) {
 167                 error("commit-graph is missing the Commit Data chunk");
 168                 return 1;
 169         }
 170
 171         return 0;
 172 }
 173
 174 struct commit_graph *parse_commit_graph(void *graph_map, int fd,
 175                                         size_t graph_size)
 176 {
 177         const unsigned char *data, *chunk_lookup;
 178         uint32_t i;
 179         struct commit_graph *graph;
 180         uint64_t last_chunk_offset;
 181         uint32_t last_chunk_id;
 182         uint32_t graph_signature;
 183         unsigned char graph_version, hash_version;
 184
 185         if (!graph_map)
 186                 return NULL;
 187
 188         if (graph_size < GRAPH_MIN_SIZE)
 189                 return NULL;
 190
 191         data = (const unsigned char *)graph_map;
 192
 193         graph_signature = get_be32(data);
 194         if (graph_signature != GRAPH_SIGNATURE) {
 195                 error(_("commit-graph signature %X does not match signature %X"),
 196                       graph_signature, GRAPH_SIGNATURE);
 197                 return NULL;
 198         }
 199
 200         graph_version = *(unsigned char*)(data + 4);
 201         if (graph_version != GRAPH_VERSION) {
 202                 error(_("commit-graph version %X does not match version %X"),
 203                       graph_version, GRAPH_VERSION);
 204                 return NULL;
 205         }
 206
 207         hash_version = *(unsigned char*)(data + 5);
 208         if (hash_version != oid_version()) {
 209                 error(_("commit-graph hash version %X does not match version %X"),
 210                       hash_version, oid_version());
 211                 return NULL;
 212         }
 213
 214         graph = alloc_commit_graph();
 215
 216         graph->hash_len = the_hash_algo->rawsz;
 217         graph->num_chunks = *(unsigned char*)(data + 6);
 218         graph->graph_fd = fd;
 219         graph->data = graph_map;
 220         graph->data_len = graph_size;
 221
 222         last_chunk_id = 0;
 223         last_chunk_offset = 8;
 224         chunk_lookup = data + 8;
 225         for (i = 0; i < graph->num_chunks; i++) {
 226                 uint32_t chunk_id;
 227                 uint64_t chunk_offset;
 228                 int chunk_repeated = 0;
 229
 230                 if (data + graph_size - chunk_lookup <
 231                     GRAPH_CHUNKLOOKUP_WIDTH) {
 232                         error(_("commit-graph chunk lookup table entry missing; file may be incomplete"));
 233                         free(graph);
 234                         return NULL;
 235                 }
 236
 237                 chunk_id = get_be32(chunk_lookup + 0);
 238                 chunk_offset = get_be64(chunk_lookup + 4);
 239
 240                 chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
 241
 242                 if (chunk_offset > graph_size - the_hash_algo->rawsz) {
 243                         error(_("commit-graph improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
 244                               (uint32_t)chunk_offset);
 245                         free(graph);
 246                         return NULL;
 247                 }
 248
 249                 switch (chunk_id) {
 250                 case GRAPH_CHUNKID_OIDFANOUT:
 251                         if (graph->chunk_oid_fanout)
 252                                 chunk_repeated = 1;
 253                         else
 254                                 graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
 255                         break;
 256
 257                 case GRAPH_CHUNKID_OIDLOOKUP:
 258                         if (graph->chunk_oid_lookup)
 259                                 chunk_repeated = 1;
 260                         else
 261                                 graph->chunk_oid_lookup = data + chunk_offset;
 262                         break;
 263
 264                 case GRAPH_CHUNKID_DATA:
 265                         if (graph->chunk_commit_data)
 266                                 chunk_repeated = 1;
 267                         else
 268                                 graph->chunk_commit_data = data + chunk_offset;
 269                         break;
 270
 271                 case GRAPH_CHUNKID_EXTRAEDGES:
 272                         if (graph->chunk_extra_edges)
 273                                 chunk_repeated = 1;
 274                         else
 275                                 graph->chunk_extra_edges = data + chunk_offset;
 276                         break;
 277
 278                 case GRAPH_CHUNKID_BASE:
 279                         if (graph->chunk_base_graphs)
 280                                 chunk_repeated = 1;
 281                         else
 282                                 graph->chunk_base_graphs = data + chunk_offset;
 283                 }
 284
 285                 if (chunk_repeated) {
 286                         error(_("commit-graph chunk id %08x appears multiple times"), chunk_id);
 287                         free(graph);
 288                         return NULL;
 289                 }
 290
 291                 if (last_chunk_id == GRAPH_CHUNKID_OIDLOOKUP)
 292                 {
 293                         graph->num_commits = (chunk_offset - last_chunk_offset)
 294                                              / graph->hash_len;
 295                 }
 296
 297                 last_chunk_id = chunk_id;
 298                 last_chunk_offset = chunk_offset;
 299         }
 300
 301         hashcpy(graph->oid.hash, graph->data + graph->data_len - graph->hash_len);
 302
 303         if (verify_commit_graph_lite(graph)) {
 304                 free(graph);
 305                 return NULL;
 306         }
 307
 308         return graph;
 309 }
 310
 311 static struct commit_graph *load_commit_graph_one(const char *graph_file)
 312 {
 313
 314         struct stat st;
 315         int fd;
 316         struct commit_graph *g;
 317         int open_ok = open_commit_graph(graph_file, &fd, &st);
 318
 319         if (!open_ok)
 320                 return NULL;
 321
 322         g = load_commit_graph_one_fd_st(fd, &st);
 323
 324         if (g)
 325                 g->filename = xstrdup(graph_file);
 326
 327         return g;
 328 }
 329
 330 static struct commit_graph *load_commit_graph_v1(struct repository *r, const char *obj_dir)
 331 {
 332         char *graph_name = get_commit_graph_filename(obj_dir);
 333         struct commit_graph *g = load_commit_graph_one(graph_name);
 334         free(graph_name);
 335
 336         if (g)
 337                 g->obj_dir = obj_dir;
 338
 339         return g;
 340 }
 341
 342 static int add_graph_to_chain(struct commit_graph *g,
 343                               struct commit_graph *chain,
 344                               struct object_id *oids,
 345                               int n)
 346 {
 347         struct commit_graph *cur_g = chain;
 348
 349         if (n && !g->chunk_base_graphs) {
 350                 warning(_("commit-graph has no base graphs chunk"));
 351                 return 0;
 352         }
 353
 354         while (n) {
 355                 n--;
 356
 357                 if (!cur_g ||
 358                     !oideq(&oids[n], &cur_g->oid) ||
 359                     !hasheq(oids[n].hash, g->chunk_base_graphs + g->hash_len * n)) {
 360                         warning(_("commit-graph chain does not match"));
 361                         return 0;
 362                 }
 363
 364                 cur_g = cur_g->base_graph;
 365         }
 366
 367         g->base_graph = chain;
 368
 369         if (chain)
 370                 g->num_commits_in_base = chain->num_commits + chain->num_commits_in_base;
 371
 372         return 1;
 373 }
 374
 375 static struct commit_graph *load_commit_graph_chain(struct repository *r, const char *obj_dir)
 376 {
 377         struct commit_graph *graph_chain = NULL;
 378         struct strbuf line = STRBUF_INIT;
 379         struct stat st;
 380         struct object_id *oids;
 381         int i = 0, valid = 1, count;
 382         char *chain_name = get_chain_filename(obj_dir);
 383         FILE *fp;
 384         int stat_res;
 385
 386         fp = fopen(chain_name, "r");
 387         stat_res = stat(chain_name, &st);
 388         free(chain_name);
 389
 390         if (!fp ||
 391             stat_res ||
 392             st.st_size <= the_hash_algo->hexsz)
 393                 return NULL;
 394
 395         count = st.st_size / (the_hash_algo->hexsz + 1);
 396         oids = xcalloc(count, sizeof(struct object_id));
 397
 398         prepare_alt_odb(r);
 399
 400         for (i = 0; i < count; i++) {
 401                 struct object_directory *odb;
 402
 403                 if (strbuf_getline_lf(&line, fp) == EOF)
 404                         break;
 405
 406                 if (get_oid_hex(line.buf, &oids[i])) {
 407                         warning(_("invalid commit-graph chain: line '%s' not a hash"),
 408                                 line.buf);
 409                         valid = 0;
 410                         break;
 411                 }
 412
 413                 valid = 0;
 414                 for (odb = r->objects->odb; odb; odb = odb->next) {
 415                         char *graph_name = get_split_graph_filename(odb->path, line.buf);
 416                         struct commit_graph *g = load_commit_graph_one(graph_name);
 417
 418                         free(graph_name);
 419
 420                         if (g) {
 421                                 g->obj_dir = odb->path;
 422
 423                                 if (add_graph_to_chain(g, graph_chain, oids, i)) {
 424                                         graph_chain = g;
 425                                         valid = 1;
 426                                 }
 427
 428                                 break;
 429                         }
 430                 }
 431
 432                 if (!valid) {
 433                         warning(_("unable to find all commit-graph files"));
 434                         break;
 435                 }
 436         }
 437
 438         free(oids);
 439         fclose(fp);
 440         strbuf_release(&line);
 441
 442         return graph_chain;
 443 }
 444
 445 struct commit_graph *read_commit_graph_one(struct repository *r, const char *obj_dir)
 446 {
 447         struct commit_graph *g = load_commit_graph_v1(r, obj_dir);
 448
 449         if (!g)
 450                 g = load_commit_graph_chain(r, obj_dir);
 451
 452         return g;
 453 }
 454
 455 static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
 456 {
 457
 458         if (r->objects->commit_graph)
 459                 return;
 460
 461         r->objects->commit_graph = read_commit_graph_one(r, obj_dir);
 462 }
 463
 464 /*
 465  * Return 1 if commit_graph is non-NULL, and 0 otherwise.
 466  *
 467  * On the first invocation, this function attemps to load the commit
 468  * graph if the_repository is configured to have one.
 469  */
 470 static int prepare_commit_graph(struct repository *r)
 471 {
 472         struct object_directory *odb;
 473
 474         /*
 475          * This must come before the "already attempted?" check below, because
 476          * we want to disable even an already-loaded graph file.
 477          */
 478         if (r->commit_graph_disabled)
 479                 return 0;
 480
 481         if (r->objects->commit_graph_attempted)
 482                 return !!r->objects->commit_graph;
 483         r->objects->commit_graph_attempted = 1;
 484
 485         if (git_env_bool(GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD, 0))
 486                 die("dying as requested by the '%s' variable on commit-graph load!",
 487                     GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD);
 488
 489         prepare_repo_settings(r);
 490
 491         if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
 492             r->settings.core_commit_graph != 1)
 493                 /*
 494                  * This repository is not configured to use commit graphs, so
 495                  * do not load one. (But report commit_graph_attempted anyway
 496                  * so that commit graph loading is not attempted again for this
 497                  * repository.)
 498                  */
 499                 return 0;
 500
 501         if (!commit_graph_compatible(r))
 502                 return 0;
 503
 504         prepare_alt_odb(r);
 505         for (odb = r->objects->odb;
 506              !r->objects->commit_graph && odb;
 507              odb = odb->next)
 508                 prepare_commit_graph_one(r, odb->path);
 509         return !!r->objects->commit_graph;
 510 }
 511
 512 int generation_numbers_enabled(struct repository *r)
 513 {
 514         uint32_t first_generation;
 515         struct commit_graph *g;
 516         if (!prepare_commit_graph(r))
 517                return 0;
 518
 519         g = r->objects->commit_graph;
 520
 521         if (!g->num_commits)
 522                 return 0;
 523
 524         first_generation = get_be32(g->chunk_commit_data +
 525                                     g->hash_len + 8) >> 2;
 526
 527         return !!first_generation;
 528 }
 529
 530 static void close_commit_graph_one(struct commit_graph *g)
 531 {
 532         if (!g)
 533                 return;
 534
 535         close_commit_graph_one(g->base_graph);
 536         free_commit_graph(g);
 537 }
 538
 539 void close_commit_graph(struct raw_object_store *o)
 540 {
 541         close_commit_graph_one(o->commit_graph);
 542         o->commit_graph = NULL;
 543 }
 544
 545 static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
 546 {
 547         return bsearch_hash(oid->hash, g->chunk_oid_fanout,
 548                             g->chunk_oid_lookup, g->hash_len, pos);
 549 }
 550
 551 static void load_oid_from_graph(struct commit_graph *g,
 552                                 uint32_t pos,
 553                                 struct object_id *oid)
 554 {
 555         uint32_t lex_index;
 556
 557         while (g && pos < g->num_commits_in_base)
 558                 g = g->base_graph;
 559
 560         if (!g)
 561                 BUG("NULL commit-graph");
 562
 563         if (pos >= g->num_commits + g->num_commits_in_base)
 564                 die(_("invalid commit position. commit-graph is likely corrupt"));
 565
 566         lex_index = pos - g->num_commits_in_base;
 567
 568         hashcpy(oid->hash, g->chunk_oid_lookup + g->hash_len * lex_index);
 569 }
 570
 571 static struct commit_list **insert_parent_or_die(struct repository *r,
 572                                                  struct commit_graph *g,
 573                                                  uint32_t pos,
 574                                                  struct commit_list **pptr)
 575 {
 576         struct commit *c;
 577         struct object_id oid;
 578
 579         if (pos >= g->num_commits + g->num_commits_in_base)
 580                 die("invalid parent position %"PRIu32, pos);
 581
 582         load_oid_from_graph(g, pos, &oid);
 583         c = lookup_commit(r, &oid);
 584         if (!c)
 585                 die(_("could not find commit %s"), oid_to_hex(&oid));
 586         c->graph_pos = pos;
 587         return &commit_list_insert(c, pptr)->next;
 588 }
 589
 590 static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
 591 {
 592         const unsigned char *commit_data;
 593         uint32_t lex_index;
 594
 595         while (pos < g->num_commits_in_base)
 596                 g = g->base_graph;
 597
 598         lex_index = pos - g->num_commits_in_base;
 599         commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * lex_index;
 600         item->graph_pos = pos;
 601         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 602 }
 603
 604 static inline void set_commit_tree(struct commit *c, struct tree *t)
 605 {
 606         c->maybe_tree = t;
 607 }
 608
 609 static int fill_commit_in_graph(struct repository *r,
 610                                 struct commit *item,
 611                                 struct commit_graph *g, uint32_t pos)
 612 {
 613         uint32_t edge_value;
 614         uint32_t *parent_data_ptr;
 615         uint64_t date_low, date_high;
 616         struct commit_list **pptr;
 617         const unsigned char *commit_data;
 618         uint32_t lex_index;
 619
 620         while (pos < g->num_commits_in_base)
 621                 g = g->base_graph;
 622
 623         if (pos >= g->num_commits + g->num_commits_in_base)
 624                 die(_("invalid commit position. commit-graph is likely corrupt"));
 625
 626         /*
 627          * Store the "full" position, but then use the
 628          * "local" position for the rest of the calculation.
 629          */
 630         item->graph_pos = pos;
 631         lex_index = pos - g->num_commits_in_base;
 632
 633         commit_data = g->chunk_commit_data + (g->hash_len + 16) * lex_index;
 634
 635         item->object.parsed = 1;
 636
 637         set_commit_tree(item, NULL);
 638
 639         date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
 640         date_low = get_be32(commit_data + g->hash_len + 12);
 641         item->date = (timestamp_t)((date_high << 32) | date_low);
 642
 643         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 644
 645         pptr = &item->parents;
 646
 647         edge_value = get_be32(commit_data + g->hash_len);
 648         if (edge_value == GRAPH_PARENT_NONE)
 649                 return 1;
 650         pptr = insert_parent_or_die(r, g, edge_value, pptr);
 651
 652         edge_value = get_be32(commit_data + g->hash_len + 4);
 653         if (edge_value == GRAPH_PARENT_NONE)
 654                 return 1;
 655         if (!(edge_value & GRAPH_EXTRA_EDGES_NEEDED)) {
 656                 pptr = insert_parent_or_die(r, g, edge_value, pptr);
 657                 return 1;
 658         }
 659
 660         parent_data_ptr = (uint32_t*)(g->chunk_extra_edges +
 661                           4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
 662         do {
 663                 edge_value = get_be32(parent_data_ptr);
 664                 pptr = insert_parent_or_die(r, g,
 665                                             edge_value & GRAPH_EDGE_LAST_MASK,
 666                                             pptr);
 667                 parent_data_ptr++;
 668         } while (!(edge_value & GRAPH_LAST_EDGE));
 669
 670         return 1;
 671 }
 672
 673 static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 674 {
 675         if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
 676                 *pos = item->graph_pos;
 677                 return 1;
 678         } else {
 679                 struct commit_graph *cur_g = g;
 680                 uint32_t lex_index;
 681
 682                 while (cur_g && !bsearch_graph(cur_g, &(item->object.oid), &lex_index))
 683                         cur_g = cur_g->base_graph;
 684
 685                 if (cur_g) {
 686                         *pos = lex_index + cur_g->num_commits_in_base;
 687                         return 1;
 688                 }
 689
 690                 return 0;
 691         }
 692 }
 693
 694 static int parse_commit_in_graph_one(struct repository *r,
 695                                      struct commit_graph *g,
 696                                      struct commit *item)
 697 {
 698         uint32_t pos;
 699
 700         if (item->object.parsed)
 701                 return 1;
 702
 703         if (find_commit_in_graph(item, g, &pos))
 704                 return fill_commit_in_graph(r, item, g, pos);
 705
 706         return 0;
 707 }
 708
 709 int parse_commit_in_graph(struct repository *r, struct commit *item)
 710 {
 711         if (!prepare_commit_graph(r))
 712                 return 0;
 713         return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
 714 }
 715
 716 void load_commit_graph_info(struct repository *r, struct commit *item)
 717 {
 718         uint32_t pos;
 719         if (!prepare_commit_graph(r))
 720                 return;
 721         if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
 722                 fill_commit_graph_info(item, r->objects->commit_graph, pos);
 723 }
 724
 725 static struct tree *load_tree_for_commit(struct repository *r,
 726                                          struct commit_graph *g,
 727                                          struct commit *c)
 728 {
 729         struct object_id oid;
 730         const unsigned char *commit_data;
 731
 732         while (c->graph_pos < g->num_commits_in_base)
 733                 g = g->base_graph;
 734
 735         commit_data = g->chunk_commit_data +
 736                         GRAPH_DATA_WIDTH * (c->graph_pos - g->num_commits_in_base);
 737
 738         hashcpy(oid.hash, commit_data);
 739         set_commit_tree(c, lookup_tree(r, &oid));
 740
 741         return c->maybe_tree;
 742 }
 743
 744 static struct tree *get_commit_tree_in_graph_one(struct repository *r,
 745                                                  struct commit_graph *g,
 746                                                  const struct commit *c)
 747 {
 748         if (c->maybe_tree)
 749                 return c->maybe_tree;
 750         if (c->graph_pos == COMMIT_NOT_FROM_GRAPH)
 751                 BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
 752
 753         return load_tree_for_commit(r, g, (struct commit *)c);
 754 }
 755
 756 struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
 757 {
 758         return get_commit_tree_in_graph_one(r, r->objects->commit_graph, c);
 759 }
 760
 761 struct packed_commit_list {
 762         struct commit **list;
 763         int nr;
 764         int alloc;
 765 };
 766
 767 struct packed_oid_list {
 768         struct object_id *list;
 769         int nr;
 770         int alloc;
 771 };
 772
 773 struct write_commit_graph_context {
 774         struct repository *r;
 775         char *obj_dir;
 776         char *graph_name;
 777         struct packed_oid_list oids;
 778         struct packed_commit_list commits;
 779         int num_extra_edges;
 780         unsigned long approx_nr_objects;
 781         struct progress *progress;
 782         int progress_done;
 783         uint64_t progress_cnt;
 784
 785         char *base_graph_name;
 786         int num_commit_graphs_before;
 787         int num_commit_graphs_after;
 788         char **commit_graph_filenames_before;
 789         char **commit_graph_filenames_after;
 790         char **commit_graph_hash_after;
 791         uint32_t new_num_commits_in_base;
 792         struct commit_graph *new_base_graph;
 793
 794         unsigned append:1,
 795                  report_progress:1,
 796                  split:1,
 797                  check_oids:1;
 798
 799         const struct split_commit_graph_opts *split_opts;
 800 };
 801
 802 static void write_graph_chunk_fanout(struct hashfile *f,
 803                                      struct write_commit_graph_context *ctx)
 804 {
 805         int i, count = 0;
 806         struct commit **list = ctx->commits.list;
 807
 808         /*
 809          * Write the first-level table (the list is sorted,
 810          * but we use a 256-entry lookup to be able to avoid
 811          * having to do eight extra binary search iterations).
 812          */
 813         for (i = 0; i < 256; i++) {
 814                 while (count < ctx->commits.nr) {
 815                         if ((*list)->object.oid.hash[0] != i)
 816                                 break;
 817                         display_progress(ctx->progress, ++ctx->progress_cnt);
 818                         count++;
 819                         list++;
 820                 }
 821
 822                 hashwrite_be32(f, count);
 823         }
 824 }
 825
 826 static void write_graph_chunk_oids(struct hashfile *f, int hash_len,
 827                                    struct write_commit_graph_context *ctx)
 828 {
 829         struct commit **list = ctx->commits.list;
 830         int count;
 831         for (count = 0; count < ctx->commits.nr; count++, list++) {
 832                 display_progress(ctx->progress, ++ctx->progress_cnt);
 833                 hashwrite(f, (*list)->object.oid.hash, (int)hash_len);
 834         }
 835 }
 836
 837 static const unsigned char *commit_to_sha1(size_t index, void *table)
 838 {
 839         struct commit **commits = table;
 840         return commits[index]->object.oid.hash;
 841 }
 842
 843 static void write_graph_chunk_data(struct hashfile *f, int hash_len,
 844                                    struct write_commit_graph_context *ctx)
 845 {
 846         struct commit **list = ctx->commits.list;
 847         struct commit **last = ctx->commits.list + ctx->commits.nr;
 848         uint32_t num_extra_edges = 0;
 849
 850         while (list < last) {
 851                 struct commit_list *parent;
 852                 struct object_id *tree;
 853                 int edge_value;
 854                 uint32_t packedDate[2];
 855                 display_progress(ctx->progress, ++ctx->progress_cnt);
 856
 857                 if (parse_commit_no_graph(*list))
 858                         die(_("unable to parse commit %s"),
 859                                 oid_to_hex(&(*list)->object.oid));
 860                 tree = get_commit_tree_oid(*list);
 861                 if (!tree)
 862                         die(_("unable to get tree for %s"),
 863                                 oid_to_hex(&(*list)->object.oid));
 864                 hashwrite(f, tree->hash, hash_len);
 865
 866                 parent = (*list)->parents;
 867
 868                 if (!parent)
 869                         edge_value = GRAPH_PARENT_NONE;
 870                 else {
 871                         edge_value = sha1_pos(parent->item->object.oid.hash,
 872                                               ctx->commits.list,
 873                                               ctx->commits.nr,
 874                                               commit_to_sha1);
 875
 876                         if (edge_value >= 0)
 877                                 edge_value += ctx->new_num_commits_in_base;
 878                         else {
 879                                 uint32_t pos;
 880                                 if (find_commit_in_graph(parent->item,
 881                                                          ctx->new_base_graph,
 882                                                          &pos))
 883                                         edge_value = pos;
 884                         }
 885
 886                         if (edge_value < 0)
 887                                 BUG("missing parent %s for commit %s",
 888                                     oid_to_hex(&parent->item->object.oid),
 889                                     oid_to_hex(&(*list)->object.oid));
 890                 }
 891
 892                 hashwrite_be32(f, edge_value);
 893
 894                 if (parent)
 895                         parent = parent->next;
 896
 897                 if (!parent)
 898                         edge_value = GRAPH_PARENT_NONE;
 899                 else if (parent->next)
 900                         edge_value = GRAPH_EXTRA_EDGES_NEEDED | num_extra_edges;
 901                 else {
 902                         edge_value = sha1_pos(parent->item->object.oid.hash,
 903                                               ctx->commits.list,
 904                                               ctx->commits.nr,
 905                                               commit_to_sha1);
 906
 907                         if (edge_value >= 0)
 908                                 edge_value += ctx->new_num_commits_in_base;
 909                         else {
 910                                 uint32_t pos;
 911                                 if (find_commit_in_graph(parent->item,
 912                                                          ctx->new_base_graph,
 913                                                          &pos))
 914                                         edge_value = pos;
 915                         }
 916
 917                         if (edge_value < 0)
 918                                 BUG("missing parent %s for commit %s",
 919                                     oid_to_hex(&parent->item->object.oid),
 920                                     oid_to_hex(&(*list)->object.oid));
 921                 }
 922
 923                 hashwrite_be32(f, edge_value);
 924
 925                 if (edge_value & GRAPH_EXTRA_EDGES_NEEDED) {
 926                         do {
 927                                 num_extra_edges++;
 928                                 parent = parent->next;
 929                         } while (parent);
 930                 }
 931
 932                 if (sizeof((*list)->date) > 4)
 933                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
 934                 else
 935                         packedDate[0] = 0;
 936
 937                 packedDate[0] |= htonl((*list)->generation << 2);
 938
 939                 packedDate[1] = htonl((*list)->date);
 940                 hashwrite(f, packedDate, 8);
 941
 942                 list++;
 943         }
 944 }
 945
 946 static void write_graph_chunk_extra_edges(struct hashfile *f,
 947                                           struct write_commit_graph_context *ctx)
 948 {
 949         struct commit **list = ctx->commits.list;
 950         struct commit **last = ctx->commits.list + ctx->commits.nr;
 951         struct commit_list *parent;
 952
 953         while (list < last) {
 954                 int num_parents = 0;
 955
 956                 display_progress(ctx->progress, ++ctx->progress_cnt);
 957
 958                 for (parent = (*list)->parents; num_parents < 3 && parent;
 959                      parent = parent->next)
 960                         num_parents++;
 961
 962                 if (num_parents <= 2) {
 963                         list++;
 964                         continue;
 965                 }
 966
 967                 /* Since num_parents > 2, this initializer is safe. */
 968                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
 969                         int edge_value = sha1_pos(parent->item->object.oid.hash,
 970                                                   ctx->commits.list,
 971                                                   ctx->commits.nr,
 972                                                   commit_to_sha1);
 973
 974                         if (edge_value >= 0)
 975                                 edge_value += ctx->new_num_commits_in_base;
 976                         else {
 977                                 uint32_t pos;
 978                                 if (find_commit_in_graph(parent->item,
 979                                                          ctx->new_base_graph,
 980                                                          &pos))
 981                                         edge_value = pos;
 982                         }
 983
 984                         if (edge_value < 0)
 985                                 BUG("missing parent %s for commit %s",
 986                                     oid_to_hex(&parent->item->object.oid),
 987                                     oid_to_hex(&(*list)->object.oid));
 988                         else if (!parent->next)
 989                                 edge_value |= GRAPH_LAST_EDGE;
 990
 991                         hashwrite_be32(f, edge_value);
 992                 }
 993
 994                 list++;
 995         }
 996 }
 997
 998 static int oid_compare(const void *_a, const void *_b)
 999 {
1000         const struct object_id *a = (const struct object_id *)_a;
1001         const struct object_id *b = (const struct object_id *)_b;
1002         return oidcmp(a, b);
1003 }
1004
1005 static int add_packed_commits(const struct object_id *oid,
1006                               struct packed_git *pack,
1007                               uint32_t pos,
1008                               void *data)
1009 {
1010         struct write_commit_graph_context *ctx = (struct write_commit_graph_context*)data;
1011         enum object_type type;
1012         off_t offset = nth_packed_object_offset(pack, pos);
1013         struct object_info oi = OBJECT_INFO_INIT;
1014
1015         if (ctx->progress)
1016                 display_progress(ctx->progress, ++ctx->progress_done);
1017
1018         oi.typep = &type;
1019         if (packed_object_info(ctx->r, pack, offset, &oi) < 0)
1020                 die(_("unable to get type of object %s"), oid_to_hex(oid));
1021
1022         if (type != OBJ_COMMIT)
1023                 return 0;
1024
1025         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1026         oidcpy(&(ctx->oids.list[ctx->oids.nr]), oid);
1027         ctx->oids.nr++;
1028
1029         return 0;
1030 }
1031
1032 static void add_missing_parents(struct write_commit_graph_context *ctx, struct commit *commit)
1033 {
1034         struct commit_list *parent;
1035         for (parent = commit->parents; parent; parent = parent->next) {
1036                 if (!(parent->item->object.flags & REACHABLE)) {
1037                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1038                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(parent->item->object.oid));
1039                         ctx->oids.nr++;
1040                         parent->item->object.flags |= REACHABLE;
1041                 }
1042         }
1043 }
1044
1045 static void close_reachable(struct write_commit_graph_context *ctx)
1046 {
1047         int i;
1048         struct commit *commit;
1049
1050         if (ctx->report_progress)
1051                 ctx->progress = start_delayed_progress(
1052                                         _("Loading known commits in commit graph"),
1053                                         ctx->oids.nr);
1054         for (i = 0; i < ctx->oids.nr; i++) {
1055                 display_progress(ctx->progress, i + 1);
1056                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1057                 if (commit)
1058                         commit->object.flags |= REACHABLE;
1059         }
1060         stop_progress(&ctx->progress);
1061
1062         /*
1063          * As this loop runs, ctx->oids.nr may grow, but not more
1064          * than the number of missing commits in the reachable
1065          * closure.
1066          */
1067         if (ctx->report_progress)
1068                 ctx->progress = start_delayed_progress(
1069                                         _("Expanding reachable commits in commit graph"),
1070                                         0);
1071         for (i = 0; i < ctx->oids.nr; i++) {
1072                 display_progress(ctx->progress, i + 1);
1073                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1074
1075                 if (!commit)
1076                         continue;
1077                 if (ctx->split) {
1078                         if (!parse_commit(commit) &&
1079                             commit->graph_pos == COMMIT_NOT_FROM_GRAPH)
1080                                 add_missing_parents(ctx, commit);
1081                 } else if (!parse_commit_no_graph(commit))
1082                         add_missing_parents(ctx, commit);
1083         }
1084         stop_progress(&ctx->progress);
1085
1086         if (ctx->report_progress)
1087                 ctx->progress = start_delayed_progress(
1088                                         _("Clearing commit marks in commit graph"),
1089                                         ctx->oids.nr);
1090         for (i = 0; i < ctx->oids.nr; i++) {
1091                 display_progress(ctx->progress, i + 1);
1092                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1093
1094                 if (commit)
1095                         commit->object.flags &= ~REACHABLE;
1096         }
1097         stop_progress(&ctx->progress);
1098 }
1099
1100 static void compute_generation_numbers(struct write_commit_graph_context *ctx)
1101 {
1102         int i;
1103         struct commit_list *list = NULL;
1104
1105         if (ctx->report_progress)
1106                 ctx->progress = start_progress(
1107                                         _("Computing commit graph generation numbers"),
1108                                         ctx->commits.nr);
1109         for (i = 0; i < ctx->commits.nr; i++) {
1110                 display_progress(ctx->progress, i + 1);
1111                 if (ctx->commits.list[i]->generation != GENERATION_NUMBER_INFINITY &&
1112                     ctx->commits.list[i]->generation != GENERATION_NUMBER_ZERO)
1113                         continue;
1114
1115                 commit_list_insert(ctx->commits.list[i], &list);
1116                 while (list) {
1117                         struct commit *current = list->item;
1118                         struct commit_list *parent;
1119                         int all_parents_computed = 1;
1120                         uint32_t max_generation = 0;
1121
1122                         for (parent = current->parents; parent; parent = parent->next) {
1123                                 if (parent->item->generation == GENERATION_NUMBER_INFINITY ||
1124                                     parent->item->generation == GENERATION_NUMBER_ZERO) {
1125                                         all_parents_computed = 0;
1126                                         commit_list_insert(parent->item, &list);
1127                                         break;
1128                                 } else if (parent->item->generation > max_generation) {
1129                                         max_generation = parent->item->generation;
1130                                 }
1131                         }
1132
1133                         if (all_parents_computed) {
1134                                 current->generation = max_generation + 1;
1135                                 pop_commit(&list);
1136
1137                                 if (current->generation > GENERATION_NUMBER_MAX)
1138                                         current->generation = GENERATION_NUMBER_MAX;
1139                         }
1140                 }
1141         }
1142         stop_progress(&ctx->progress);
1143 }
1144
1145 static int add_ref_to_list(const char *refname,
1146                            const struct object_id *oid,
1147                            int flags, void *cb_data)
1148 {
1149         struct string_list *list = (struct string_list *)cb_data;
1150
1151         string_list_append(list, oid_to_hex(oid));
1152         return 0;
1153 }
1154
1155 int write_commit_graph_reachable(const char *obj_dir,
1156                                  enum commit_graph_write_flags flags,
1157                                  const struct split_commit_graph_opts *split_opts)
1158 {
1159         struct string_list list = STRING_LIST_INIT_DUP;
1160         int result;
1161
1162         for_each_ref(add_ref_to_list, &list);
1163         result = write_commit_graph(obj_dir, NULL, &list,
1164                                     flags, split_opts);
1165
1166         string_list_clear(&list, 0);
1167         return result;
1168 }
1169
1170 static int fill_oids_from_packs(struct write_commit_graph_context *ctx,
1171                                 struct string_list *pack_indexes)
1172 {
1173         uint32_t i;
1174         struct strbuf progress_title = STRBUF_INIT;
1175         struct strbuf packname = STRBUF_INIT;
1176         int dirlen;
1177
1178         strbuf_addf(&packname, "%s/pack/", ctx->obj_dir);
1179         dirlen = packname.len;
1180         if (ctx->report_progress) {
1181                 strbuf_addf(&progress_title,
1182                             Q_("Finding commits for commit graph in %d pack",
1183                                "Finding commits for commit graph in %d packs",
1184                                pack_indexes->nr),
1185                             pack_indexes->nr);
1186                 ctx->progress = start_delayed_progress(progress_title.buf, 0);
1187                 ctx->progress_done = 0;
1188         }
1189         for (i = 0; i < pack_indexes->nr; i++) {
1190                 struct packed_git *p;
1191                 strbuf_setlen(&packname, dirlen);
1192                 strbuf_addstr(&packname, pack_indexes->items[i].string);
1193                 p = add_packed_git(packname.buf, packname.len, 1);
1194                 if (!p) {
1195                         error(_("error adding pack %s"), packname.buf);
1196                         return -1;
1197                 }
1198                 if (open_pack_index(p)) {
1199                         error(_("error opening index for %s"), packname.buf);
1200                         return -1;
1201                 }
1202                 for_each_object_in_pack(p, add_packed_commits, ctx,
1203                                         FOR_EACH_OBJECT_PACK_ORDER);
1204                 close_pack(p);
1205                 free(p);
1206         }
1207
1208         stop_progress(&ctx->progress);
1209         strbuf_release(&progress_title);
1210         strbuf_release(&packname);
1211
1212         return 0;
1213 }
1214
1215 static int fill_oids_from_commit_hex(struct write_commit_graph_context *ctx,
1216                                      struct string_list *commit_hex)
1217 {
1218         uint32_t i;
1219         struct strbuf progress_title = STRBUF_INIT;
1220
1221         if (ctx->report_progress) {
1222                 strbuf_addf(&progress_title,
1223                             Q_("Finding commits for commit graph from %d ref",
1224                                "Finding commits for commit graph from %d refs",
1225                                commit_hex->nr),
1226                             commit_hex->nr);
1227                 ctx->progress = start_delayed_progress(
1228                                         progress_title.buf,
1229                                         commit_hex->nr);
1230         }
1231         for (i = 0; i < commit_hex->nr; i++) {
1232                 const char *end;
1233                 struct object_id oid;
1234                 struct commit *result;
1235
1236                 display_progress(ctx->progress, i + 1);
1237                 if (!parse_oid_hex(commit_hex->items[i].string, &oid, &end) &&
1238                     (result = lookup_commit_reference_gently(ctx->r, &oid, 1))) {
1239                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1240                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(result->object.oid));
1241                         ctx->oids.nr++;
1242                 } else if (ctx->check_oids) {
1243                         error(_("invalid commit object id: %s"),
1244                             commit_hex->items[i].string);
1245                         return -1;
1246                 }
1247         }
1248         stop_progress(&ctx->progress);
1249         strbuf_release(&progress_title);
1250
1251         return 0;
1252 }
1253
1254 static void fill_oids_from_all_packs(struct write_commit_graph_context *ctx)
1255 {
1256         if (ctx->report_progress)
1257                 ctx->progress = start_delayed_progress(
1258                         _("Finding commits for commit graph among packed objects"),
1259                         ctx->approx_nr_objects);
1260         for_each_packed_object(add_packed_commits, ctx,
1261                                FOR_EACH_OBJECT_PACK_ORDER);
1262         if (ctx->progress_done < ctx->approx_nr_objects)
1263                 display_progress(ctx->progress, ctx->approx_nr_objects);
1264         stop_progress(&ctx->progress);
1265 }
1266
1267 static uint32_t count_distinct_commits(struct write_commit_graph_context *ctx)
1268 {
1269         uint32_t i, count_distinct = 1;
1270
1271         if (ctx->report_progress)
1272                 ctx->progress = start_delayed_progress(
1273                         _("Counting distinct commits in commit graph"),
1274                         ctx->oids.nr);
1275         display_progress(ctx->progress, 0); /* TODO: Measure QSORT() progress */
1276         QSORT(ctx->oids.list, ctx->oids.nr, oid_compare);
1277
1278         for (i = 1; i < ctx->oids.nr; i++) {
1279                 display_progress(ctx->progress, i + 1);
1280                 if (!oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i])) {
1281                         if (ctx->split) {
1282                                 struct commit *c = lookup_commit(ctx->r, &ctx->oids.list[i]);
1283
1284                                 if (!c || c->graph_pos != COMMIT_NOT_FROM_GRAPH)
1285                                         continue;
1286                         }
1287
1288                         count_distinct++;
1289                 }
1290         }
1291         stop_progress(&ctx->progress);
1292
1293         return count_distinct;
1294 }
1295
1296 static void copy_oids_to_commits(struct write_commit_graph_context *ctx)
1297 {
1298         uint32_t i;
1299
1300         ctx->num_extra_edges = 0;
1301         if (ctx->report_progress)
1302                 ctx->progress = start_delayed_progress(
1303                         _("Finding extra edges in commit graph"),
1304                         ctx->oids.nr);
1305         for (i = 0; i < ctx->oids.nr; i++) {
1306                 unsigned int num_parents;
1307
1308                 display_progress(ctx->progress, i + 1);
1309                 if (i > 0 && oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i]))
1310                         continue;
1311
1312                 ALLOC_GROW(ctx->commits.list, ctx->commits.nr + 1, ctx->commits.alloc);
1313                 ctx->commits.list[ctx->commits.nr] = lookup_commit(ctx->r, &ctx->oids.list[i]);
1314
1315                 if (ctx->split &&
1316                     ctx->commits.list[ctx->commits.nr]->graph_pos != COMMIT_NOT_FROM_GRAPH)
1317                         continue;
1318
1319                 parse_commit_no_graph(ctx->commits.list[ctx->commits.nr]);
1320
1321                 num_parents = commit_list_count(ctx->commits.list[ctx->commits.nr]->parents);
1322                 if (num_parents > 2)
1323                         ctx->num_extra_edges += num_parents - 1;
1324
1325                 ctx->commits.nr++;
1326         }
1327         stop_progress(&ctx->progress);
1328 }
1329
1330 static int write_graph_chunk_base_1(struct hashfile *f,
1331                                     struct commit_graph *g)
1332 {
1333         int num = 0;
1334
1335         if (!g)
1336                 return 0;
1337
1338         num = write_graph_chunk_base_1(f, g->base_graph);
1339         hashwrite(f, g->oid.hash, the_hash_algo->rawsz);
1340         return num + 1;
1341 }
1342
1343 static int write_graph_chunk_base(struct hashfile *f,
1344                                   struct write_commit_graph_context *ctx)
1345 {
1346         int num = write_graph_chunk_base_1(f, ctx->new_base_graph);
1347
1348         if (num != ctx->num_commit_graphs_after - 1) {
1349                 error(_("failed to write correct number of base graph ids"));
1350                 return -1;
1351         }
1352
1353         return 0;
1354 }
1355
1356 static int write_commit_graph_file(struct write_commit_graph_context *ctx)
1357 {
1358         uint32_t i;
1359         int fd;
1360         struct hashfile *f;
1361         struct lock_file lk = LOCK_INIT;
1362         uint32_t chunk_ids[6];
1363         uint64_t chunk_offsets[6];
1364         const unsigned hashsz = the_hash_algo->rawsz;
1365         struct strbuf progress_title = STRBUF_INIT;
1366         int num_chunks = 3;
1367         struct object_id file_hash;
1368
1369         if (ctx->split) {
1370                 struct strbuf tmp_file = STRBUF_INIT;
1371
1372                 strbuf_addf(&tmp_file,
1373                             "%s/info/commit-graphs/tmp_graph_XXXXXX",
1374                             ctx->obj_dir);
1375                 ctx->graph_name = strbuf_detach(&tmp_file, NULL);
1376         } else {
1377                 ctx->graph_name = get_commit_graph_filename(ctx->obj_dir);
1378         }
1379
1380         if (safe_create_leading_directories(ctx->graph_name)) {
1381                 UNLEAK(ctx->graph_name);
1382                 error(_("unable to create leading directories of %s"),
1383                         ctx->graph_name);
1384                 return -1;
1385         }
1386
1387         if (ctx->split) {
1388                 char *lock_name = get_chain_filename(ctx->obj_dir);
1389
1390                 hold_lock_file_for_update(&lk, lock_name, LOCK_DIE_ON_ERROR);
1391
1392                 fd = git_mkstemp_mode(ctx->graph_name, 0444);
1393                 if (fd < 0) {
1394                         error(_("unable to create '%s'"), ctx->graph_name);
1395                         return -1;
1396                 }
1397
1398                 f = hashfd(fd, ctx->graph_name);
1399         } else {
1400                 hold_lock_file_for_update(&lk, ctx->graph_name, LOCK_DIE_ON_ERROR);
1401                 fd = lk.tempfile->fd;
1402                 f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
1403         }
1404
1405         chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
1406         chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
1407         chunk_ids[2] = GRAPH_CHUNKID_DATA;
1408         if (ctx->num_extra_edges) {
1409                 chunk_ids[num_chunks] = GRAPH_CHUNKID_EXTRAEDGES;
1410                 num_chunks++;
1411         }
1412         if (ctx->num_commit_graphs_after > 1) {
1413                 chunk_ids[num_chunks] = GRAPH_CHUNKID_BASE;
1414                 num_chunks++;
1415         }
1416
1417         chunk_ids[num_chunks] = 0;
1418
1419         chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
1420         chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
1421         chunk_offsets[2] = chunk_offsets[1] + hashsz * ctx->commits.nr;
1422         chunk_offsets[3] = chunk_offsets[2] + (hashsz + 16) * ctx->commits.nr;
1423
1424         num_chunks = 3;
1425         if (ctx->num_extra_edges) {
1426                 chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
1427                                                 4 * ctx->num_extra_edges;
1428                 num_chunks++;
1429         }
1430         if (ctx->num_commit_graphs_after > 1) {
1431                 chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
1432                                                 hashsz * (ctx->num_commit_graphs_after - 1);
1433                 num_chunks++;
1434         }
1435
1436         hashwrite_be32(f, GRAPH_SIGNATURE);
1437
1438         hashwrite_u8(f, GRAPH_VERSION);
1439         hashwrite_u8(f, oid_version());
1440         hashwrite_u8(f, num_chunks);
1441         hashwrite_u8(f, ctx->num_commit_graphs_after - 1);
1442
1443         for (i = 0; i <= num_chunks; i++) {
1444                 uint32_t chunk_write[3];
1445
1446                 chunk_write[0] = htonl(chunk_ids[i]);
1447                 chunk_write[1] = htonl(chunk_offsets[i] >> 32);
1448                 chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
1449                 hashwrite(f, chunk_write, 12);
1450         }
1451
1452         if (ctx->report_progress) {
1453                 strbuf_addf(&progress_title,
1454                             Q_("Writing out commit graph in %d pass",
1455                                "Writing out commit graph in %d passes",
1456                                num_chunks),
1457                             num_chunks);
1458                 ctx->progress = start_delayed_progress(
1459                         progress_title.buf,
1460                         num_chunks * ctx->commits.nr);
1461         }
1462         write_graph_chunk_fanout(f, ctx);
1463         write_graph_chunk_oids(f, hashsz, ctx);
1464         write_graph_chunk_data(f, hashsz, ctx);
1465         if (ctx->num_extra_edges)
1466                 write_graph_chunk_extra_edges(f, ctx);
1467         if (ctx->num_commit_graphs_after > 1 &&
1468             write_graph_chunk_base(f, ctx)) {
1469                 return -1;
1470         }
1471         stop_progress(&ctx->progress);
1472         strbuf_release(&progress_title);
1473
1474         if (ctx->split && ctx->base_graph_name && ctx->num_commit_graphs_after > 1) {
1475                 char *new_base_hash = xstrdup(oid_to_hex(&ctx->new_base_graph->oid));
1476                 char *new_base_name = get_split_graph_filename(ctx->new_base_graph->obj_dir, new_base_hash);
1477
1478                 free(ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2]);
1479                 free(ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2]);
1480                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2] = new_base_name;
1481                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2] = new_base_hash;
1482         }
1483
1484         close_commit_graph(ctx->r->objects);
1485         finalize_hashfile(f, file_hash.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
1486
1487         if (ctx->split) {
1488                 FILE *chainf = fdopen_lock_file(&lk, "w");
1489                 char *final_graph_name;
1490                 int result;
1491
1492                 close(fd);
1493
1494                 if (!chainf) {
1495                         error(_("unable to open commit-graph chain file"));
1496                         return -1;
1497                 }
1498
1499                 if (ctx->base_graph_name) {
1500                         const char *dest = ctx->commit_graph_filenames_after[
1501                                                 ctx->num_commit_graphs_after - 2];
1502
1503                         if (strcmp(ctx->base_graph_name, dest)) {
1504                                 result = rename(ctx->base_graph_name, dest);
1505
1506                                 if (result) {
1507                                         error(_("failed to rename base commit-graph file"));
1508                                         return -1;
1509                                 }
1510                         }
1511                 } else {
1512                         char *graph_name = get_commit_graph_filename(ctx->obj_dir);
1513                         unlink(graph_name);
1514                 }
1515
1516                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(oid_to_hex(&file_hash));
1517                 final_graph_name = get_split_graph_filename(ctx->obj_dir,
1518                                         ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
1519                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1] = final_graph_name;
1520
1521                 result = rename(ctx->graph_name, final_graph_name);
1522
1523                 for (i = 0; i < ctx->num_commit_graphs_after; i++)
1524                         fprintf(lk.tempfile->fp, "%s\n", ctx->commit_graph_hash_after[i]);
1525
1526                 if (result) {
1527                         error(_("failed to rename temporary commit-graph file"));
1528                         return -1;
1529                 }
1530         }
1531
1532         commit_lock_file(&lk);
1533
1534         return 0;
1535 }
1536
1537 static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
1538 {
1539         struct commit_graph *g;
1540         uint32_t num_commits;
1541         uint32_t i;
1542
1543         int max_commits = 0;
1544         int size_mult = 2;
1545
1546         if (ctx->split_opts) {
1547                 max_commits = ctx->split_opts->max_commits;
1548                 size_mult = ctx->split_opts->size_multiple;
1549         }
1550
1551         g = ctx->r->objects->commit_graph;
1552         num_commits = ctx->commits.nr;
1553         ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1;
1554
1555         while (g && (g->num_commits <= size_mult * num_commits ||
1556                     (max_commits && num_commits > max_commits))) {
1557                 if (strcmp(g->obj_dir, ctx->obj_dir))
1558                         break;
1559
1560                 num_commits += g->num_commits;
1561                 g = g->base_graph;
1562
1563                 ctx->num_commit_graphs_after--;
1564         }
1565
1566         ctx->new_base_graph = g;
1567
1568         if (ctx->num_commit_graphs_after == 2) {
1569                 char *old_graph_name = get_commit_graph_filename(g->obj_dir);
1570
1571                 if (!strcmp(g->filename, old_graph_name) &&
1572                     strcmp(g->obj_dir, ctx->obj_dir)) {
1573                         ctx->num_commit_graphs_after = 1;
1574                         ctx->new_base_graph = NULL;
1575                 }
1576
1577                 free(old_graph_name);
1578         }
1579
1580         ALLOC_ARRAY(ctx->commit_graph_filenames_after, ctx->num_commit_graphs_after);
1581         ALLOC_ARRAY(ctx->commit_graph_hash_after, ctx->num_commit_graphs_after);
1582
1583         for (i = 0; i < ctx->num_commit_graphs_after &&
1584                     i < ctx->num_commit_graphs_before; i++)
1585                 ctx->commit_graph_filenames_after[i] = xstrdup(ctx->commit_graph_filenames_before[i]);
1586
1587         i = ctx->num_commit_graphs_before - 1;
1588         g = ctx->r->objects->commit_graph;
1589
1590         while (g) {
1591                 if (i < ctx->num_commit_graphs_after)
1592                         ctx->commit_graph_hash_after[i] = xstrdup(oid_to_hex(&g->oid));
1593
1594                 i--;
1595                 g = g->base_graph;
1596         }
1597 }
1598
1599 static void merge_commit_graph(struct write_commit_graph_context *ctx,
1600                                struct commit_graph *g)
1601 {
1602         uint32_t i;
1603         uint32_t offset = g->num_commits_in_base;
1604
1605         ALLOC_GROW(ctx->commits.list, ctx->commits.nr + g->num_commits, ctx->commits.alloc);
1606
1607         for (i = 0; i < g->num_commits; i++) {
1608                 struct object_id oid;
1609                 struct commit *result;
1610
1611                 display_progress(ctx->progress, i + 1);
1612
1613                 load_oid_from_graph(g, i + offset, &oid);
1614
1615                 /* only add commits if they still exist in the repo */
1616                 result = lookup_commit_reference_gently(ctx->r, &oid, 1);
1617
1618                 if (result) {
1619                         ctx->commits.list[ctx->commits.nr] = result;
1620                         ctx->commits.nr++;
1621                 }
1622         }
1623 }
1624
1625 static int commit_compare(const void *_a, const void *_b)
1626 {
1627         const struct commit *a = *(const struct commit **)_a;
1628         const struct commit *b = *(const struct commit **)_b;
1629         return oidcmp(&a->object.oid, &b->object.oid);
1630 }
1631
1632 static void sort_and_scan_merged_commits(struct write_commit_graph_context *ctx)
1633 {
1634         uint32_t i;
1635
1636         if (ctx->report_progress)
1637                 ctx->progress = start_delayed_progress(
1638                                         _("Scanning merged commits"),
1639                                         ctx->commits.nr);
1640
1641         QSORT(ctx->commits.list, ctx->commits.nr, commit_compare);
1642
1643         ctx->num_extra_edges = 0;
1644         for (i = 0; i < ctx->commits.nr; i++) {
1645                 display_progress(ctx->progress, i);
1646
1647                 if (i && oideq(&ctx->commits.list[i - 1]->object.oid,
1648                           &ctx->commits.list[i]->object.oid)) {
1649                         die(_("unexpected duplicate commit id %s"),
1650                             oid_to_hex(&ctx->commits.list[i]->object.oid));
1651                 } else {
1652                         unsigned int num_parents;
1653
1654                         num_parents = commit_list_count(ctx->commits.list[i]->parents);
1655                         if (num_parents > 2)
1656                                 ctx->num_extra_edges += num_parents - 1;
1657                 }
1658         }
1659
1660         stop_progress(&ctx->progress);
1661 }
1662
1663 static void merge_commit_graphs(struct write_commit_graph_context *ctx)
1664 {
1665         struct commit_graph *g = ctx->r->objects->commit_graph;
1666         uint32_t current_graph_number = ctx->num_commit_graphs_before;
1667         struct strbuf progress_title = STRBUF_INIT;
1668
1669         while (g && current_graph_number >= ctx->num_commit_graphs_after) {
1670                 current_graph_number--;
1671
1672                 if (ctx->report_progress) {
1673                         strbuf_addstr(&progress_title, _("Merging commit-graph"));
1674                         ctx->progress = start_delayed_progress(progress_title.buf, 0);
1675                 }
1676
1677                 merge_commit_graph(ctx, g);
1678                 stop_progress(&ctx->progress);
1679                 strbuf_release(&progress_title);
1680
1681                 g = g->base_graph;
1682         }
1683
1684         if (g) {
1685                 ctx->new_base_graph = g;
1686                 ctx->new_num_commits_in_base = g->num_commits + g->num_commits_in_base;
1687         }
1688
1689         if (ctx->new_base_graph)
1690                 ctx->base_graph_name = xstrdup(ctx->new_base_graph->filename);
1691
1692         sort_and_scan_merged_commits(ctx);
1693 }
1694
1695 static void mark_commit_graphs(struct write_commit_graph_context *ctx)
1696 {
1697         uint32_t i;
1698         time_t now = time(NULL);
1699
1700         for (i = ctx->num_commit_graphs_after - 1; i < ctx->num_commit_graphs_before; i++) {
1701                 struct stat st;
1702                 struct utimbuf updated_time;
1703
1704                 stat(ctx->commit_graph_filenames_before[i], &st);
1705
1706                 updated_time.actime = st.st_atime;
1707                 updated_time.modtime = now;
1708                 utime(ctx->commit_graph_filenames_before[i], &updated_time);
1709         }
1710 }
1711
1712 static void expire_commit_graphs(struct write_commit_graph_context *ctx)
1713 {
1714         struct strbuf path = STRBUF_INIT;
1715         DIR *dir;
1716         struct dirent *de;
1717         size_t dirnamelen;
1718         timestamp_t expire_time = time(NULL);
1719
1720         if (ctx->split_opts && ctx->split_opts->expire_time)
1721                 expire_time -= ctx->split_opts->expire_time;
1722         if (!ctx->split) {
1723                 char *chain_file_name = get_chain_filename(ctx->obj_dir);
1724                 unlink(chain_file_name);
1725                 free(chain_file_name);
1726                 ctx->num_commit_graphs_after = 0;
1727         }
1728
1729         strbuf_addstr(&path, ctx->obj_dir);
1730         strbuf_addstr(&path, "/info/commit-graphs");
1731         dir = opendir(path.buf);
1732
1733         if (!dir)
1734                 goto out;
1735
1736         strbuf_addch(&path, '/');
1737         dirnamelen = path.len;
1738         while ((de = readdir(dir)) != NULL) {
1739                 struct stat st;
1740                 uint32_t i, found = 0;
1741
1742                 strbuf_setlen(&path, dirnamelen);
1743                 strbuf_addstr(&path, de->d_name);
1744
1745                 stat(path.buf, &st);
1746
1747                 if (st.st_mtime > expire_time)
1748                         continue;
1749                 if (path.len < 6 || strcmp(path.buf + path.len - 6, ".graph"))
1750                         continue;
1751
1752                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
1753                         if (!strcmp(ctx->commit_graph_filenames_after[i],
1754                                     path.buf)) {
1755                                 found = 1;
1756                                 break;
1757                         }
1758                 }
1759
1760                 if (!found)
1761                         unlink(path.buf);
1762         }
1763
1764 out:
1765         strbuf_release(&path);
1766 }
1767
1768 int write_commit_graph(const char *obj_dir,
1769                        struct string_list *pack_indexes,
1770                        struct string_list *commit_hex,
1771                        enum commit_graph_write_flags flags,
1772                        const struct split_commit_graph_opts *split_opts)
1773 {
1774         struct write_commit_graph_context *ctx;
1775         uint32_t i, count_distinct = 0;
1776         size_t len;
1777         int res = 0;
1778
1779         if (!commit_graph_compatible(the_repository))
1780                 return 0;
1781
1782         ctx = xcalloc(1, sizeof(struct write_commit_graph_context));
1783         ctx->r = the_repository;
1784
1785         /* normalize object dir with no trailing slash */
1786         ctx->obj_dir = xmallocz(strlen(obj_dir) + 1);
1787         normalize_path_copy(ctx->obj_dir, obj_dir);
1788         len = strlen(ctx->obj_dir);
1789         if (len && ctx->obj_dir[len - 1] == '/')
1790                 ctx->obj_dir[len - 1] = 0;
1791
1792         ctx->append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0;
1793         ctx->report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0;
1794         ctx->split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
1795         ctx->check_oids = flags & COMMIT_GRAPH_WRITE_CHECK_OIDS ? 1 : 0;
1796         ctx->split_opts = split_opts;
1797
1798         if (ctx->split) {
1799                 struct commit_graph *g;
1800                 prepare_commit_graph(ctx->r);
1801
1802                 g = ctx->r->objects->commit_graph;
1803
1804                 while (g) {
1805                         ctx->num_commit_graphs_before++;
1806                         g = g->base_graph;
1807                 }
1808
1809                 if (ctx->num_commit_graphs_before) {
1810                         ALLOC_ARRAY(ctx->commit_graph_filenames_before, ctx->num_commit_graphs_before);
1811                         i = ctx->num_commit_graphs_before;
1812                         g = ctx->r->objects->commit_graph;
1813
1814                         while (g) {
1815                                 ctx->commit_graph_filenames_before[--i] = xstrdup(g->filename);
1816                                 g = g->base_graph;
1817                         }
1818                 }
1819         }
1820
1821         ctx->approx_nr_objects = approximate_object_count();
1822         ctx->oids.alloc = ctx->approx_nr_objects / 32;
1823
1824         if (ctx->split && split_opts && ctx->oids.alloc > split_opts->max_commits)
1825                 ctx->oids.alloc = split_opts->max_commits;
1826
1827         if (ctx->append) {
1828                 prepare_commit_graph_one(ctx->r, ctx->obj_dir);
1829                 if (ctx->r->objects->commit_graph)
1830                         ctx->oids.alloc += ctx->r->objects->commit_graph->num_commits;
1831         }
1832
1833         if (ctx->oids.alloc < 1024)
1834                 ctx->oids.alloc = 1024;
1835         ALLOC_ARRAY(ctx->oids.list, ctx->oids.alloc);
1836
1837         if (ctx->append && ctx->r->objects->commit_graph) {
1838                 struct commit_graph *g = ctx->r->objects->commit_graph;
1839                 for (i = 0; i < g->num_commits; i++) {
1840                         const unsigned char *hash = g->chunk_oid_lookup + g->hash_len * i;
1841                         hashcpy(ctx->oids.list[ctx->oids.nr++].hash, hash);
1842                 }
1843         }
1844
1845         if (pack_indexes) {
1846                 if ((res = fill_oids_from_packs(ctx, pack_indexes)))
1847                         goto cleanup;
1848         }
1849
1850         if (commit_hex) {
1851                 if ((res = fill_oids_from_commit_hex(ctx, commit_hex)))
1852                         goto cleanup;
1853         }
1854
1855         if (!pack_indexes && !commit_hex)
1856                 fill_oids_from_all_packs(ctx);
1857
1858         close_reachable(ctx);
1859
1860         count_distinct = count_distinct_commits(ctx);
1861
1862         if (count_distinct >= GRAPH_EDGE_LAST_MASK) {
1863                 error(_("the commit graph format cannot write %d commits"), count_distinct);
1864                 res = -1;
1865                 goto cleanup;
1866         }
1867
1868         ctx->commits.alloc = count_distinct;
1869         ALLOC_ARRAY(ctx->commits.list, ctx->commits.alloc);
1870
1871         copy_oids_to_commits(ctx);
1872
1873         if (ctx->commits.nr >= GRAPH_EDGE_LAST_MASK) {
1874                 error(_("too many commits to write graph"));
1875                 res = -1;
1876                 goto cleanup;
1877         }
1878
1879         if (!ctx->commits.nr)
1880                 goto cleanup;
1881
1882         if (ctx->split) {
1883                 split_graph_merge_strategy(ctx);
1884
1885                 merge_commit_graphs(ctx);
1886         } else
1887                 ctx->num_commit_graphs_after = 1;
1888
1889         compute_generation_numbers(ctx);
1890
1891         res = write_commit_graph_file(ctx);
1892
1893         if (ctx->split)
1894                 mark_commit_graphs(ctx);
1895
1896         expire_commit_graphs(ctx);
1897
1898 cleanup:
1899         free(ctx->graph_name);
1900         free(ctx->commits.list);
1901         free(ctx->oids.list);
1902         free(ctx->obj_dir);
1903
1904         if (ctx->commit_graph_filenames_after) {
1905                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
1906                         free(ctx->commit_graph_filenames_after[i]);
1907                         free(ctx->commit_graph_hash_after[i]);
1908                 }
1909
1910                 for (i = 0; i < ctx->num_commit_graphs_before; i++)
1911                         free(ctx->commit_graph_filenames_before[i]);
1912
1913                 free(ctx->commit_graph_filenames_after);
1914                 free(ctx->commit_graph_filenames_before);
1915                 free(ctx->commit_graph_hash_after);
1916         }
1917
1918         free(ctx);
1919
1920         return res;
1921 }
1922
1923 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
1924 static int verify_commit_graph_error;
1925
1926 static void graph_report(const char *fmt, ...)
1927 {
1928         va_list ap;
1929
1930         verify_commit_graph_error = 1;
1931         va_start(ap, fmt);
1932         vfprintf(stderr, fmt, ap);
1933         fprintf(stderr, "\n");
1934         va_end(ap);
1935 }
1936
1937 #define GENERATION_ZERO_EXISTS 1
1938 #define GENERATION_NUMBER_EXISTS 2
1939
1940 int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
1941 {
1942         uint32_t i, cur_fanout_pos = 0;
1943         struct object_id prev_oid, cur_oid, checksum;
1944         int generation_zero = 0;
1945         struct hashfile *f;
1946         int devnull;
1947         struct progress *progress = NULL;
1948         int local_error = 0;
1949
1950         if (!g) {
1951                 graph_report("no commit-graph file loaded");
1952                 return 1;
1953         }
1954
1955         verify_commit_graph_error = verify_commit_graph_lite(g);
1956         if (verify_commit_graph_error)
1957                 return verify_commit_graph_error;
1958
1959         devnull = open("/dev/null", O_WRONLY);
1960         f = hashfd(devnull, NULL);
1961         hashwrite(f, g->data, g->data_len - g->hash_len);
1962         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
1963         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
1964                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
1965                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
1966         }
1967
1968         for (i = 0; i < g->num_commits; i++) {
1969                 struct commit *graph_commit;
1970
1971                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1972
1973                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
1974                         graph_report(_("commit-graph has incorrect OID order: %s then %s"),
1975                                      oid_to_hex(&prev_oid),
1976                                      oid_to_hex(&cur_oid));
1977
1978                 oidcpy(&prev_oid, &cur_oid);
1979
1980                 while (cur_oid.hash[0] > cur_fanout_pos) {
1981                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1982
1983                         if (i != fanout_value)
1984                                 graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
1985                                              cur_fanout_pos, fanout_value, i);
1986                         cur_fanout_pos++;
1987                 }
1988
1989                 graph_commit = lookup_commit(r, &cur_oid);
1990                 if (!parse_commit_in_graph_one(r, g, graph_commit))
1991                         graph_report(_("failed to parse commit %s from commit-graph"),
1992                                      oid_to_hex(&cur_oid));
1993         }
1994
1995         while (cur_fanout_pos < 256) {
1996                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1997
1998                 if (g->num_commits != fanout_value)
1999                         graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
2000                                      cur_fanout_pos, fanout_value, i);
2001
2002                 cur_fanout_pos++;
2003         }
2004
2005         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
2006                 return verify_commit_graph_error;
2007
2008         if (flags & COMMIT_GRAPH_WRITE_PROGRESS)
2009                 progress = start_progress(_("Verifying commits in commit graph"),
2010                                         g->num_commits);
2011
2012         for (i = 0; i < g->num_commits; i++) {
2013                 struct commit *graph_commit, *odb_commit;
2014                 struct commit_list *graph_parents, *odb_parents;
2015                 uint32_t max_generation = 0;
2016
2017                 display_progress(progress, i + 1);
2018                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
2019
2020                 graph_commit = lookup_commit(r, &cur_oid);
2021                 odb_commit = (struct commit *)create_object(r, &cur_oid, alloc_commit_node(r));
2022                 if (parse_commit_internal(odb_commit, 0, 0)) {
2023                         graph_report(_("failed to parse commit %s from object database for commit-graph"),
2024                                      oid_to_hex(&cur_oid));
2025                         continue;
2026                 }
2027
2028                 if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
2029                            get_commit_tree_oid(odb_commit)))
2030                         graph_report(_("root tree OID for commit %s in commit-graph is %s != %s"),
2031                                      oid_to_hex(&cur_oid),
2032                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
2033                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
2034
2035                 graph_parents = graph_commit->parents;
2036                 odb_parents = odb_commit->parents;
2037
2038                 while (graph_parents) {
2039                         if (odb_parents == NULL) {
2040                                 graph_report(_("commit-graph parent list for commit %s is too long"),
2041                                              oid_to_hex(&cur_oid));
2042                                 break;
2043                         }
2044
2045                         /* parse parent in case it is in a base graph */
2046                         parse_commit_in_graph_one(r, g, graph_parents->item);
2047
2048                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
2049                                 graph_report(_("commit-graph parent for %s is %s != %s"),
2050                                              oid_to_hex(&cur_oid),
2051                                              oid_to_hex(&graph_parents->item->object.oid),
2052                                              oid_to_hex(&odb_parents->item->object.oid));
2053
2054                         if (graph_parents->item->generation > max_generation)
2055                                 max_generation = graph_parents->item->generation;
2056
2057                         graph_parents = graph_parents->next;
2058                         odb_parents = odb_parents->next;
2059                 }
2060
2061                 if (odb_parents != NULL)
2062                         graph_report(_("commit-graph parent list for commit %s terminates early"),
2063                                      oid_to_hex(&cur_oid));
2064
2065                 if (!graph_commit->generation) {
2066                         if (generation_zero == GENERATION_NUMBER_EXISTS)
2067                                 graph_report(_("commit-graph has generation number zero for commit %s, but non-zero elsewhere"),
2068                                              oid_to_hex(&cur_oid));
2069                         generation_zero = GENERATION_ZERO_EXISTS;
2070                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
2071                         graph_report(_("commit-graph has non-zero generation number for commit %s, but zero elsewhere"),
2072                                      oid_to_hex(&cur_oid));
2073
2074                 if (generation_zero == GENERATION_ZERO_EXISTS)
2075                         continue;
2076
2077                 /*
2078                  * If one of our parents has generation GENERATION_NUMBER_MAX, then
2079                  * our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
2080                  * extra logic in the following condition.
2081                  */
2082                 if (max_generation == GENERATION_NUMBER_MAX)
2083                         max_generation--;
2084
2085                 if (graph_commit->generation != max_generation + 1)
2086                         graph_report(_("commit-graph generation for commit %s is %u != %u"),
2087                                      oid_to_hex(&cur_oid),
2088                                      graph_commit->generation,
2089                                      max_generation + 1);
2090
2091                 if (graph_commit->date != odb_commit->date)
2092                         graph_report(_("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime),
2093                                      oid_to_hex(&cur_oid),
2094                                      graph_commit->date,
2095                                      odb_commit->date);
2096         }
2097         stop_progress(&progress);
2098
2099         local_error = verify_commit_graph_error;
2100
2101         if (!(flags & COMMIT_GRAPH_VERIFY_SHALLOW) && g->base_graph)
2102                 local_error |= verify_commit_graph(r, g->base_graph, flags);
2103
2104         return local_error;
2105 }
2106
2107 void free_commit_graph(struct commit_graph *g)
2108 {
2109         if (!g)
2110                 return;
2111         if (g->graph_fd >= 0) {
2112                 munmap((void *)g->data, g->data_len);
2113                 g->data = NULL;
2114                 close(g->graph_fd);
2115         }
2116         free(g->filename);
2117         free(g);
2118 }
2119
2120 void disable_commit_graph(struct repository *r)
2121 {
2122         r->commit_graph_disabled = 1;
2123 }