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

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "dir.h"
   4 #include "git-compat-util.h"
   5 #include "lockfile.h"
   6 #include "pack.h"
   7 #include "packfile.h"
   8 #include "commit.h"
   9 #include "object.h"
  10 #include "refs.h"
  11 #include "revision.h"
  12 #include "sha1-lookup.h"
  13 #include "commit-graph.h"
  14 #include "object-store.h"
  15 #include "alloc.h"
  16 #include "hashmap.h"
  17 #include "replace-object.h"
  18 #include "progress.h"
  19
  20 #define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */
  21 #define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
  22 #define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
  23 #define GRAPH_CHUNKID_DATA 0x43444154 /* "CDAT" */
  24 #define GRAPH_CHUNKID_EXTRAEDGES 0x45444745 /* "EDGE" */
  25 #define GRAPH_CHUNKID_BASE 0x42415345 /* "BASE" */
  26
  27 #define GRAPH_DATA_WIDTH (the_hash_algo->rawsz + 16)
  28
  29 #define GRAPH_VERSION_1 0x1
  30 #define GRAPH_VERSION GRAPH_VERSION_1
  31
  32 #define GRAPH_EXTRA_EDGES_NEEDED 0x80000000
  33 #define GRAPH_EDGE_LAST_MASK 0x7fffffff
  34 #define GRAPH_PARENT_NONE 0x70000000
  35
  36 #define GRAPH_LAST_EDGE 0x80000000
  37
  38 #define GRAPH_HEADER_SIZE 8
  39 #define GRAPH_FANOUT_SIZE (4 * 256)
  40 #define GRAPH_CHUNKLOOKUP_WIDTH 12
  41 #define GRAPH_MIN_SIZE (GRAPH_HEADER_SIZE + 4 * GRAPH_CHUNKLOOKUP_WIDTH \
  42                         + GRAPH_FANOUT_SIZE + the_hash_algo->rawsz)
  43
  44 char *get_commit_graph_filename(const char *obj_dir)
  45 {
  46         char *filename = xstrfmt("%s/info/commit-graph", obj_dir);
  47         char *normalized = xmalloc(strlen(filename) + 1);
  48         normalize_path_copy(normalized, filename);
  49         free(filename);
  50         return normalized;
  51 }
  52
  53 static char *get_split_graph_filename(const char *obj_dir,
  54                                       const char *oid_hex)
  55 {
  56         char *filename = xstrfmt("%s/info/commit-graphs/graph-%s.graph",
  57                                  obj_dir,
  58                                  oid_hex);
  59         char *normalized = xmalloc(strlen(filename) + 1);
  60         normalize_path_copy(normalized, filename);
  61         free(filename);
  62         return normalized;
  63 }
  64
  65 static char *get_chain_filename(const char *obj_dir)
  66 {
  67         return xstrfmt("%s/info/commit-graphs/commit-graph-chain", obj_dir);
  68 }
  69
  70 static uint8_t oid_version(void)
  71 {
  72         return 1;
  73 }
  74
  75 static struct commit_graph *alloc_commit_graph(void)
  76 {
  77         struct commit_graph *g = xcalloc(1, sizeof(*g));
  78         g->graph_fd = -1;
  79
  80         return g;
  81 }
  82
  83 extern int read_replace_refs;
  84
  85 static int commit_graph_compatible(struct repository *r)
  86 {
  87         if (!r->gitdir)
  88                 return 0;
  89
  90         if (read_replace_refs) {
  91                 prepare_replace_object(r);
  92                 if (hashmap_get_size(&r->objects->replace_map->map))
  93                         return 0;
  94         }
  95
  96         prepare_commit_graft(r);
  97         if (r->parsed_objects && r->parsed_objects->grafts_nr)
  98                 return 0;
  99         if (is_repository_shallow(r))
 100                 return 0;
 101
 102         return 1;
 103 }
 104
 105 int open_commit_graph(const char *graph_file, int *fd, struct stat *st)
 106 {
 107         *fd = git_open(graph_file);
 108         if (*fd < 0)
 109                 return 0;
 110         if (fstat(*fd, st)) {
 111                 close(*fd);
 112                 return 0;
 113         }
 114         return 1;
 115 }
 116
 117 struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st)
 118 {
 119         void *graph_map;
 120         size_t graph_size;
 121         struct commit_graph *ret;
 122
 123         graph_size = xsize_t(st->st_size);
 124
 125         if (graph_size < GRAPH_MIN_SIZE) {
 126                 close(fd);
 127                 error(_("commit-graph file is too small"));
 128                 return NULL;
 129         }
 130         graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
 131         ret = parse_commit_graph(graph_map, fd, graph_size);
 132
 133         if (!ret) {
 134                 munmap(graph_map, graph_size);
 135                 close(fd);
 136         }
 137
 138         return ret;
 139 }
 140
 141 static int verify_commit_graph_lite(struct commit_graph *g)
 142 {
 143         /*
 144          * Basic validation shared between parse_commit_graph()
 145          * which'll be called every time the graph is used, and the
 146          * much more expensive verify_commit_graph() used by
 147          * "commit-graph verify".
 148          *
 149          * There should only be very basic checks here to ensure that
 150          * we don't e.g. segfault in fill_commit_in_graph(), but
 151          * because this is a very hot codepath nothing that e.g. loops
 152          * over g->num_commits, or runs a checksum on the commit-graph
 153          * itself.
 154          */
 155         if (!g->chunk_oid_fanout) {
 156                 error("commit-graph is missing the OID Fanout chunk");
 157                 return 1;
 158         }
 159         if (!g->chunk_oid_lookup) {
 160                 error("commit-graph is missing the OID Lookup chunk");
 161                 return 1;
 162         }
 163         if (!g->chunk_commit_data) {
 164                 error("commit-graph is missing the Commit Data chunk");
 165                 return 1;
 166         }
 167
 168         return 0;
 169 }
 170
 171 struct commit_graph *parse_commit_graph(void *graph_map, int fd,
 172                                         size_t graph_size)
 173 {
 174         const unsigned char *data, *chunk_lookup;
 175         uint32_t i;
 176         struct commit_graph *graph;
 177         uint64_t last_chunk_offset;
 178         uint32_t last_chunk_id;
 179         uint32_t graph_signature;
 180         unsigned char graph_version, hash_version;
 181
 182         if (!graph_map)
 183                 return NULL;
 184
 185         if (graph_size < GRAPH_MIN_SIZE)
 186                 return NULL;
 187
 188         data = (const unsigned char *)graph_map;
 189
 190         graph_signature = get_be32(data);
 191         if (graph_signature != GRAPH_SIGNATURE) {
 192                 error(_("commit-graph signature %X does not match signature %X"),
 193                       graph_signature, GRAPH_SIGNATURE);
 194                 return NULL;
 195         }
 196
 197         graph_version = *(unsigned char*)(data + 4);
 198         if (graph_version != GRAPH_VERSION) {
 199                 error(_("commit-graph version %X does not match version %X"),
 200                       graph_version, GRAPH_VERSION);
 201                 return NULL;
 202         }
 203
 204         hash_version = *(unsigned char*)(data + 5);
 205         if (hash_version != oid_version()) {
 206                 error(_("commit-graph hash version %X does not match version %X"),
 207                       hash_version, oid_version());
 208                 return NULL;
 209         }
 210
 211         graph = alloc_commit_graph();
 212
 213         graph->hash_len = the_hash_algo->rawsz;
 214         graph->num_chunks = *(unsigned char*)(data + 6);
 215         graph->graph_fd = fd;
 216         graph->data = graph_map;
 217         graph->data_len = graph_size;
 218
 219         last_chunk_id = 0;
 220         last_chunk_offset = 8;
 221         chunk_lookup = data + 8;
 222         for (i = 0; i < graph->num_chunks; i++) {
 223                 uint32_t chunk_id;
 224                 uint64_t chunk_offset;
 225                 int chunk_repeated = 0;
 226
 227                 if (data + graph_size - chunk_lookup <
 228                     GRAPH_CHUNKLOOKUP_WIDTH) {
 229                         error(_("commit-graph chunk lookup table entry missing; file may be incomplete"));
 230                         free(graph);
 231                         return NULL;
 232                 }
 233
 234                 chunk_id = get_be32(chunk_lookup + 0);
 235                 chunk_offset = get_be64(chunk_lookup + 4);
 236
 237                 chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
 238
 239                 if (chunk_offset > graph_size - the_hash_algo->rawsz) {
 240                         error(_("commit-graph improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
 241                               (uint32_t)chunk_offset);
 242                         free(graph);
 243                         return NULL;
 244                 }
 245
 246                 switch (chunk_id) {
 247                 case GRAPH_CHUNKID_OIDFANOUT:
 248                         if (graph->chunk_oid_fanout)
 249                                 chunk_repeated = 1;
 250                         else
 251                                 graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
 252                         break;
 253
 254                 case GRAPH_CHUNKID_OIDLOOKUP:
 255                         if (graph->chunk_oid_lookup)
 256                                 chunk_repeated = 1;
 257                         else
 258                                 graph->chunk_oid_lookup = data + chunk_offset;
 259                         break;
 260
 261                 case GRAPH_CHUNKID_DATA:
 262                         if (graph->chunk_commit_data)
 263                                 chunk_repeated = 1;
 264                         else
 265                                 graph->chunk_commit_data = data + chunk_offset;
 266                         break;
 267
 268                 case GRAPH_CHUNKID_EXTRAEDGES:
 269                         if (graph->chunk_extra_edges)
 270                                 chunk_repeated = 1;
 271                         else
 272                                 graph->chunk_extra_edges = data + chunk_offset;
 273                         break;
 274
 275                 case GRAPH_CHUNKID_BASE:
 276                         if (graph->chunk_base_graphs)
 277                                 chunk_repeated = 1;
 278                         else
 279                                 graph->chunk_base_graphs = data + chunk_offset;
 280                 }
 281
 282                 if (chunk_repeated) {
 283                         error(_("commit-graph chunk id %08x appears multiple times"), chunk_id);
 284                         free(graph);
 285                         return NULL;
 286                 }
 287
 288                 if (last_chunk_id == GRAPH_CHUNKID_OIDLOOKUP)
 289                 {
 290                         graph->num_commits = (chunk_offset - last_chunk_offset)
 291                                              / graph->hash_len;
 292                 }
 293
 294                 last_chunk_id = chunk_id;
 295                 last_chunk_offset = chunk_offset;
 296         }
 297
 298         hashcpy(graph->oid.hash, graph->data + graph->data_len - graph->hash_len);
 299
 300         if (verify_commit_graph_lite(graph)) {
 301                 free(graph);
 302                 return NULL;
 303         }
 304
 305         return graph;
 306 }
 307
 308 static struct commit_graph *load_commit_graph_one(const char *graph_file)
 309 {
 310
 311         struct stat st;
 312         int fd;
 313         struct commit_graph *g;
 314         int open_ok = open_commit_graph(graph_file, &fd, &st);
 315
 316         if (!open_ok)
 317                 return NULL;
 318
 319         g = load_commit_graph_one_fd_st(fd, &st);
 320
 321         if (g)
 322                 g->filename = xstrdup(graph_file);
 323
 324         return g;
 325 }
 326
 327 static struct commit_graph *load_commit_graph_v1(struct repository *r, const char *obj_dir)
 328 {
 329         char *graph_name = get_commit_graph_filename(obj_dir);
 330         struct commit_graph *g = load_commit_graph_one(graph_name);
 331         free(graph_name);
 332
 333         if (g)
 334                 g->obj_dir = obj_dir;
 335
 336         return g;
 337 }
 338
 339 static int add_graph_to_chain(struct commit_graph *g,
 340                               struct commit_graph *chain,
 341                               struct object_id *oids,
 342                               int n)
 343 {
 344         struct commit_graph *cur_g = chain;
 345
 346         if (n && !g->chunk_base_graphs) {
 347                 warning(_("commit-graph has no base graphs chunk"));
 348                 return 0;
 349         }
 350
 351         while (n) {
 352                 n--;
 353
 354                 if (!cur_g ||
 355                     !oideq(&oids[n], &cur_g->oid) ||
 356                     !hasheq(oids[n].hash, g->chunk_base_graphs + g->hash_len * n)) {
 357                         warning(_("commit-graph chain does not match"));
 358                         return 0;
 359                 }
 360
 361                 cur_g = cur_g->base_graph;
 362         }
 363
 364         g->base_graph = chain;
 365
 366         if (chain)
 367                 g->num_commits_in_base = chain->num_commits + chain->num_commits_in_base;
 368
 369         return 1;
 370 }
 371
 372 static struct commit_graph *load_commit_graph_chain(struct repository *r, const char *obj_dir)
 373 {
 374         struct commit_graph *graph_chain = NULL;
 375         struct strbuf line = STRBUF_INIT;
 376         struct stat st;
 377         struct object_id *oids;
 378         int i = 0, valid = 1, count;
 379         char *chain_name = get_chain_filename(obj_dir);
 380         FILE *fp;
 381         int stat_res;
 382
 383         fp = fopen(chain_name, "r");
 384         stat_res = stat(chain_name, &st);
 385         free(chain_name);
 386
 387         if (!fp ||
 388             stat_res ||
 389             st.st_size <= the_hash_algo->hexsz)
 390                 return NULL;
 391
 392         count = st.st_size / (the_hash_algo->hexsz + 1);
 393         oids = xcalloc(count, sizeof(struct object_id));
 394
 395         prepare_alt_odb(r);
 396
 397         for (i = 0; i < count; i++) {
 398                 struct object_directory *odb;
 399
 400                 if (strbuf_getline_lf(&line, fp) == EOF)
 401                         break;
 402
 403                 if (get_oid_hex(line.buf, &oids[i])) {
 404                         warning(_("invalid commit-graph chain: line '%s' not a hash"),
 405                                 line.buf);
 406                         valid = 0;
 407                         break;
 408                 }
 409
 410                 valid = 0;
 411                 for (odb = r->objects->odb; odb; odb = odb->next) {
 412                         char *graph_name = get_split_graph_filename(odb->path, line.buf);
 413                         struct commit_graph *g = load_commit_graph_one(graph_name);
 414
 415                         free(graph_name);
 416
 417                         if (g) {
 418                                 g->obj_dir = odb->path;
 419
 420                                 if (add_graph_to_chain(g, graph_chain, oids, i)) {
 421                                         graph_chain = g;
 422                                         valid = 1;
 423                                 }
 424
 425                                 break;
 426                         }
 427                 }
 428
 429                 if (!valid) {
 430                         warning(_("unable to find all commit-graph files"));
 431                         break;
 432                 }
 433         }
 434
 435         free(oids);
 436         fclose(fp);
 437         strbuf_release(&line);
 438
 439         return graph_chain;
 440 }
 441
 442 struct commit_graph *read_commit_graph_one(struct repository *r, const char *obj_dir)
 443 {
 444         struct commit_graph *g = load_commit_graph_v1(r, obj_dir);
 445
 446         if (!g)
 447                 g = load_commit_graph_chain(r, obj_dir);
 448
 449         return g;
 450 }
 451
 452 static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
 453 {
 454
 455         if (r->objects->commit_graph)
 456                 return;
 457
 458         r->objects->commit_graph = read_commit_graph_one(r, obj_dir);
 459 }
 460
 461 /*
 462  * Return 1 if commit_graph is non-NULL, and 0 otherwise.
 463  *
 464  * On the first invocation, this function attemps to load the commit
 465  * graph if the_repository is configured to have one.
 466  */
 467 static int prepare_commit_graph(struct repository *r)
 468 {
 469         struct object_directory *odb;
 470         int config_value;
 471
 472         if (git_env_bool(GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD, 0))
 473                 die("dying as requested by the '%s' variable on commit-graph load!",
 474                     GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD);
 475
 476         if (r->objects->commit_graph_attempted)
 477                 return !!r->objects->commit_graph;
 478         r->objects->commit_graph_attempted = 1;
 479
 480         if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
 481             (repo_config_get_bool(r, "core.commitgraph", &config_value) ||
 482             !config_value))
 483                 /*
 484                  * This repository is not configured to use commit graphs, so
 485                  * do not load one. (But report commit_graph_attempted anyway
 486                  * so that commit graph loading is not attempted again for this
 487                  * repository.)
 488                  */
 489                 return 0;
 490
 491         if (!commit_graph_compatible(r))
 492                 return 0;
 493
 494         prepare_alt_odb(r);
 495         for (odb = r->objects->odb;
 496              !r->objects->commit_graph && odb;
 497              odb = odb->next)
 498                 prepare_commit_graph_one(r, odb->path);
 499         return !!r->objects->commit_graph;
 500 }
 501
 502 int generation_numbers_enabled(struct repository *r)
 503 {
 504         uint32_t first_generation;
 505         struct commit_graph *g;
 506         if (!prepare_commit_graph(r))
 507                return 0;
 508
 509         g = r->objects->commit_graph;
 510
 511         if (!g->num_commits)
 512                 return 0;
 513
 514         first_generation = get_be32(g->chunk_commit_data +
 515                                     g->hash_len + 8) >> 2;
 516
 517         return !!first_generation;
 518 }
 519
 520 static void close_commit_graph_one(struct commit_graph *g)
 521 {
 522         if (!g)
 523                 return;
 524
 525         close_commit_graph_one(g->base_graph);
 526         free_commit_graph(g);
 527 }
 528
 529 void close_commit_graph(struct raw_object_store *o)
 530 {
 531         close_commit_graph_one(o->commit_graph);
 532         o->commit_graph = NULL;
 533 }
 534
 535 static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
 536 {
 537         return bsearch_hash(oid->hash, g->chunk_oid_fanout,
 538                             g->chunk_oid_lookup, g->hash_len, pos);
 539 }
 540
 541 static void load_oid_from_graph(struct commit_graph *g,
 542                                 uint32_t pos,
 543                                 struct object_id *oid)
 544 {
 545         uint32_t lex_index;
 546
 547         while (g && pos < g->num_commits_in_base)
 548                 g = g->base_graph;
 549
 550         if (!g)
 551                 BUG("NULL commit-graph");
 552
 553         if (pos >= g->num_commits + g->num_commits_in_base)
 554                 die(_("invalid commit position. commit-graph is likely corrupt"));
 555
 556         lex_index = pos - g->num_commits_in_base;
 557
 558         hashcpy(oid->hash, g->chunk_oid_lookup + g->hash_len * lex_index);
 559 }
 560
 561 static struct commit_list **insert_parent_or_die(struct repository *r,
 562                                                  struct commit_graph *g,
 563                                                  uint32_t pos,
 564                                                  struct commit_list **pptr)
 565 {
 566         struct commit *c;
 567         struct object_id oid;
 568
 569         if (pos >= g->num_commits + g->num_commits_in_base)
 570                 die("invalid parent position %"PRIu32, pos);
 571
 572         load_oid_from_graph(g, pos, &oid);
 573         c = lookup_commit(r, &oid);
 574         if (!c)
 575                 die(_("could not find commit %s"), oid_to_hex(&oid));
 576         c->graph_pos = pos;
 577         return &commit_list_insert(c, pptr)->next;
 578 }
 579
 580 static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
 581 {
 582         const unsigned char *commit_data;
 583         uint32_t lex_index;
 584
 585         while (pos < g->num_commits_in_base)
 586                 g = g->base_graph;
 587
 588         lex_index = pos - g->num_commits_in_base;
 589         commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * lex_index;
 590         item->graph_pos = pos;
 591         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 592 }
 593
 594 static inline void set_commit_tree(struct commit *c, struct tree *t)
 595 {
 596         c->maybe_tree = t;
 597 }
 598
 599 static int fill_commit_in_graph(struct repository *r,
 600                                 struct commit *item,
 601                                 struct commit_graph *g, uint32_t pos)
 602 {
 603         uint32_t edge_value;
 604         uint32_t *parent_data_ptr;
 605         uint64_t date_low, date_high;
 606         struct commit_list **pptr;
 607         const unsigned char *commit_data;
 608         uint32_t lex_index;
 609
 610         while (pos < g->num_commits_in_base)
 611                 g = g->base_graph;
 612
 613         if (pos >= g->num_commits + g->num_commits_in_base)
 614                 die(_("invalid commit position. commit-graph is likely corrupt"));
 615
 616         /*
 617          * Store the "full" position, but then use the
 618          * "local" position for the rest of the calculation.
 619          */
 620         item->graph_pos = pos;
 621         lex_index = pos - g->num_commits_in_base;
 622
 623         commit_data = g->chunk_commit_data + (g->hash_len + 16) * lex_index;
 624
 625         item->object.parsed = 1;
 626
 627         set_commit_tree(item, NULL);
 628
 629         date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
 630         date_low = get_be32(commit_data + g->hash_len + 12);
 631         item->date = (timestamp_t)((date_high << 32) | date_low);
 632
 633         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 634
 635         pptr = &item->parents;
 636
 637         edge_value = get_be32(commit_data + g->hash_len);
 638         if (edge_value == GRAPH_PARENT_NONE)
 639                 return 1;
 640         pptr = insert_parent_or_die(r, g, edge_value, pptr);
 641
 642         edge_value = get_be32(commit_data + g->hash_len + 4);
 643         if (edge_value == GRAPH_PARENT_NONE)
 644                 return 1;
 645         if (!(edge_value & GRAPH_EXTRA_EDGES_NEEDED)) {
 646                 pptr = insert_parent_or_die(r, g, edge_value, pptr);
 647                 return 1;
 648         }
 649
 650         parent_data_ptr = (uint32_t*)(g->chunk_extra_edges +
 651                           4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
 652         do {
 653                 edge_value = get_be32(parent_data_ptr);
 654                 pptr = insert_parent_or_die(r, g,
 655                                             edge_value & GRAPH_EDGE_LAST_MASK,
 656                                             pptr);
 657                 parent_data_ptr++;
 658         } while (!(edge_value & GRAPH_LAST_EDGE));
 659
 660         return 1;
 661 }
 662
 663 static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 664 {
 665         if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
 666                 *pos = item->graph_pos;
 667                 return 1;
 668         } else {
 669                 struct commit_graph *cur_g = g;
 670                 uint32_t lex_index;
 671
 672                 while (cur_g && !bsearch_graph(cur_g, &(item->object.oid), &lex_index))
 673                         cur_g = cur_g->base_graph;
 674
 675                 if (cur_g) {
 676                         *pos = lex_index + cur_g->num_commits_in_base;
 677                         return 1;
 678                 }
 679
 680                 return 0;
 681         }
 682 }
 683
 684 static int parse_commit_in_graph_one(struct repository *r,
 685                                      struct commit_graph *g,
 686                                      struct commit *item)
 687 {
 688         uint32_t pos;
 689
 690         if (item->object.parsed)
 691                 return 1;
 692
 693         if (find_commit_in_graph(item, g, &pos))
 694                 return fill_commit_in_graph(r, item, g, pos);
 695
 696         return 0;
 697 }
 698
 699 int parse_commit_in_graph(struct repository *r, struct commit *item)
 700 {
 701         if (!prepare_commit_graph(r))
 702                 return 0;
 703         return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
 704 }
 705
 706 void load_commit_graph_info(struct repository *r, struct commit *item)
 707 {
 708         uint32_t pos;
 709         if (!prepare_commit_graph(r))
 710                 return;
 711         if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
 712                 fill_commit_graph_info(item, r->objects->commit_graph, pos);
 713 }
 714
 715 static struct tree *load_tree_for_commit(struct repository *r,
 716                                          struct commit_graph *g,
 717                                          struct commit *c)
 718 {
 719         struct object_id oid;
 720         const unsigned char *commit_data;
 721
 722         while (c->graph_pos < g->num_commits_in_base)
 723                 g = g->base_graph;
 724
 725         commit_data = g->chunk_commit_data +
 726                         GRAPH_DATA_WIDTH * (c->graph_pos - g->num_commits_in_base);
 727
 728         hashcpy(oid.hash, commit_data);
 729         set_commit_tree(c, lookup_tree(r, &oid));
 730
 731         return c->maybe_tree;
 732 }
 733
 734 static struct tree *get_commit_tree_in_graph_one(struct repository *r,
 735                                                  struct commit_graph *g,
 736                                                  const struct commit *c)
 737 {
 738         if (c->maybe_tree)
 739                 return c->maybe_tree;
 740         if (c->graph_pos == COMMIT_NOT_FROM_GRAPH)
 741                 BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
 742
 743         return load_tree_for_commit(r, g, (struct commit *)c);
 744 }
 745
 746 struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
 747 {
 748         return get_commit_tree_in_graph_one(r, r->objects->commit_graph, c);
 749 }
 750
 751 struct packed_commit_list {
 752         struct commit **list;
 753         int nr;
 754         int alloc;
 755 };
 756
 757 struct packed_oid_list {
 758         struct object_id *list;
 759         int nr;
 760         int alloc;
 761 };
 762
 763 struct write_commit_graph_context {
 764         struct repository *r;
 765         char *obj_dir;
 766         char *graph_name;
 767         struct packed_oid_list oids;
 768         struct packed_commit_list commits;
 769         int num_extra_edges;
 770         unsigned long approx_nr_objects;
 771         struct progress *progress;
 772         int progress_done;
 773         uint64_t progress_cnt;
 774
 775         char *base_graph_name;
 776         int num_commit_graphs_before;
 777         int num_commit_graphs_after;
 778         char **commit_graph_filenames_before;
 779         char **commit_graph_filenames_after;
 780         char **commit_graph_hash_after;
 781         uint32_t new_num_commits_in_base;
 782         struct commit_graph *new_base_graph;
 783
 784         unsigned append:1,
 785                  report_progress:1,
 786                  split:1,
 787                  check_oids:1;
 788
 789         const struct split_commit_graph_opts *split_opts;
 790 };
 791
 792 static void write_graph_chunk_fanout(struct hashfile *f,
 793                                      struct write_commit_graph_context *ctx)
 794 {
 795         int i, count = 0;
 796         struct commit **list = ctx->commits.list;
 797
 798         /*
 799          * Write the first-level table (the list is sorted,
 800          * but we use a 256-entry lookup to be able to avoid
 801          * having to do eight extra binary search iterations).
 802          */
 803         for (i = 0; i < 256; i++) {
 804                 while (count < ctx->commits.nr) {
 805                         if ((*list)->object.oid.hash[0] != i)
 806                                 break;
 807                         display_progress(ctx->progress, ++ctx->progress_cnt);
 808                         count++;
 809                         list++;
 810                 }
 811
 812                 hashwrite_be32(f, count);
 813         }
 814 }
 815
 816 static void write_graph_chunk_oids(struct hashfile *f, int hash_len,
 817                                    struct write_commit_graph_context *ctx)
 818 {
 819         struct commit **list = ctx->commits.list;
 820         int count;
 821         for (count = 0; count < ctx->commits.nr; count++, list++) {
 822                 display_progress(ctx->progress, ++ctx->progress_cnt);
 823                 hashwrite(f, (*list)->object.oid.hash, (int)hash_len);
 824         }
 825 }
 826
 827 static const unsigned char *commit_to_sha1(size_t index, void *table)
 828 {
 829         struct commit **commits = table;
 830         return commits[index]->object.oid.hash;
 831 }
 832
 833 static void write_graph_chunk_data(struct hashfile *f, int hash_len,
 834                                    struct write_commit_graph_context *ctx)
 835 {
 836         struct commit **list = ctx->commits.list;
 837         struct commit **last = ctx->commits.list + ctx->commits.nr;
 838         uint32_t num_extra_edges = 0;
 839
 840         while (list < last) {
 841                 struct commit_list *parent;
 842                 int edge_value;
 843                 uint32_t packedDate[2];
 844                 display_progress(ctx->progress, ++ctx->progress_cnt);
 845
 846                 parse_commit_no_graph(*list);
 847                 hashwrite(f, get_commit_tree_oid(*list)->hash, hash_len);
 848
 849                 parent = (*list)->parents;
 850
 851                 if (!parent)
 852                         edge_value = GRAPH_PARENT_NONE;
 853                 else {
 854                         edge_value = sha1_pos(parent->item->object.oid.hash,
 855                                               ctx->commits.list,
 856                                               ctx->commits.nr,
 857                                               commit_to_sha1);
 858
 859                         if (edge_value >= 0)
 860                                 edge_value += ctx->new_num_commits_in_base;
 861                         else {
 862                                 uint32_t pos;
 863                                 if (find_commit_in_graph(parent->item,
 864                                                          ctx->new_base_graph,
 865                                                          &pos))
 866                                         edge_value = pos;
 867                         }
 868
 869                         if (edge_value < 0)
 870                                 BUG("missing parent %s for commit %s",
 871                                     oid_to_hex(&parent->item->object.oid),
 872                                     oid_to_hex(&(*list)->object.oid));
 873                 }
 874
 875                 hashwrite_be32(f, edge_value);
 876
 877                 if (parent)
 878                         parent = parent->next;
 879
 880                 if (!parent)
 881                         edge_value = GRAPH_PARENT_NONE;
 882                 else if (parent->next)
 883                         edge_value = GRAPH_EXTRA_EDGES_NEEDED | num_extra_edges;
 884                 else {
 885                         edge_value = sha1_pos(parent->item->object.oid.hash,
 886                                               ctx->commits.list,
 887                                               ctx->commits.nr,
 888                                               commit_to_sha1);
 889
 890                         if (edge_value >= 0)
 891                                 edge_value += ctx->new_num_commits_in_base;
 892                         else {
 893                                 uint32_t pos;
 894                                 if (find_commit_in_graph(parent->item,
 895                                                          ctx->new_base_graph,
 896                                                          &pos))
 897                                         edge_value = pos;
 898                         }
 899
 900                         if (edge_value < 0)
 901                                 BUG("missing parent %s for commit %s",
 902                                     oid_to_hex(&parent->item->object.oid),
 903                                     oid_to_hex(&(*list)->object.oid));
 904                 }
 905
 906                 hashwrite_be32(f, edge_value);
 907
 908                 if (edge_value & GRAPH_EXTRA_EDGES_NEEDED) {
 909                         do {
 910                                 num_extra_edges++;
 911                                 parent = parent->next;
 912                         } while (parent);
 913                 }
 914
 915                 if (sizeof((*list)->date) > 4)
 916                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
 917                 else
 918                         packedDate[0] = 0;
 919
 920                 packedDate[0] |= htonl((*list)->generation << 2);
 921
 922                 packedDate[1] = htonl((*list)->date);
 923                 hashwrite(f, packedDate, 8);
 924
 925                 list++;
 926         }
 927 }
 928
 929 static void write_graph_chunk_extra_edges(struct hashfile *f,
 930                                           struct write_commit_graph_context *ctx)
 931 {
 932         struct commit **list = ctx->commits.list;
 933         struct commit **last = ctx->commits.list + ctx->commits.nr;
 934         struct commit_list *parent;
 935
 936         while (list < last) {
 937                 int num_parents = 0;
 938
 939                 display_progress(ctx->progress, ++ctx->progress_cnt);
 940
 941                 for (parent = (*list)->parents; num_parents < 3 && parent;
 942                      parent = parent->next)
 943                         num_parents++;
 944
 945                 if (num_parents <= 2) {
 946                         list++;
 947                         continue;
 948                 }
 949
 950                 /* Since num_parents > 2, this initializer is safe. */
 951                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
 952                         int edge_value = sha1_pos(parent->item->object.oid.hash,
 953                                                   ctx->commits.list,
 954                                                   ctx->commits.nr,
 955                                                   commit_to_sha1);
 956
 957                         if (edge_value >= 0)
 958                                 edge_value += ctx->new_num_commits_in_base;
 959                         else {
 960                                 uint32_t pos;
 961                                 if (find_commit_in_graph(parent->item,
 962                                                          ctx->new_base_graph,
 963                                                          &pos))
 964                                         edge_value = pos;
 965                         }
 966
 967                         if (edge_value < 0)
 968                                 BUG("missing parent %s for commit %s",
 969                                     oid_to_hex(&parent->item->object.oid),
 970                                     oid_to_hex(&(*list)->object.oid));
 971                         else if (!parent->next)
 972                                 edge_value |= GRAPH_LAST_EDGE;
 973
 974                         hashwrite_be32(f, edge_value);
 975                 }
 976
 977                 list++;
 978         }
 979 }
 980
 981 static int oid_compare(const void *_a, const void *_b)
 982 {
 983         const struct object_id *a = (const struct object_id *)_a;
 984         const struct object_id *b = (const struct object_id *)_b;
 985         return oidcmp(a, b);
 986 }
 987
 988 static int add_packed_commits(const struct object_id *oid,
 989                               struct packed_git *pack,
 990                               uint32_t pos,
 991                               void *data)
 992 {
 993         struct write_commit_graph_context *ctx = (struct write_commit_graph_context*)data;
 994         enum object_type type;
 995         off_t offset = nth_packed_object_offset(pack, pos);
 996         struct object_info oi = OBJECT_INFO_INIT;
 997
 998         if (ctx->progress)
 999                 display_progress(ctx->progress, ++ctx->progress_done);
1000
1001         oi.typep = &type;
1002         if (packed_object_info(ctx->r, pack, offset, &oi) < 0)
1003                 die(_("unable to get type of object %s"), oid_to_hex(oid));
1004
1005         if (type != OBJ_COMMIT)
1006                 return 0;
1007
1008         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1009         oidcpy(&(ctx->oids.list[ctx->oids.nr]), oid);
1010         ctx->oids.nr++;
1011
1012         return 0;
1013 }
1014
1015 static void add_missing_parents(struct write_commit_graph_context *ctx, struct commit *commit)
1016 {
1017         struct commit_list *parent;
1018         for (parent = commit->parents; parent; parent = parent->next) {
1019                 if (!(parent->item->object.flags & UNINTERESTING)) {
1020                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1021                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(parent->item->object.oid));
1022                         ctx->oids.nr++;
1023                         parent->item->object.flags |= UNINTERESTING;
1024                 }
1025         }
1026 }
1027
1028 static void close_reachable(struct write_commit_graph_context *ctx)
1029 {
1030         int i;
1031         struct commit *commit;
1032
1033         if (ctx->report_progress)
1034                 ctx->progress = start_delayed_progress(
1035                                         _("Loading known 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                 if (commit)
1041                         commit->object.flags |= UNINTERESTING;
1042         }
1043         stop_progress(&ctx->progress);
1044
1045         /*
1046          * As this loop runs, ctx->oids.nr may grow, but not more
1047          * than the number of missing commits in the reachable
1048          * closure.
1049          */
1050         if (ctx->report_progress)
1051                 ctx->progress = start_delayed_progress(
1052                                         _("Expanding reachable 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
1058                 if (!commit)
1059                         continue;
1060                 if (ctx->split) {
1061                         if (!parse_commit(commit) &&
1062                             commit->graph_pos == COMMIT_NOT_FROM_GRAPH)
1063                                 add_missing_parents(ctx, commit);
1064                 } else if (!parse_commit_no_graph(commit))
1065                         add_missing_parents(ctx, commit);
1066         }
1067         stop_progress(&ctx->progress);
1068
1069         if (ctx->report_progress)
1070                 ctx->progress = start_delayed_progress(
1071                                         _("Clearing commit marks in commit graph"),
1072                                         ctx->oids.nr);
1073         for (i = 0; i < ctx->oids.nr; i++) {
1074                 display_progress(ctx->progress, i + 1);
1075                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1076
1077                 if (commit)
1078                         commit->object.flags &= ~UNINTERESTING;
1079         }
1080         stop_progress(&ctx->progress);
1081 }
1082
1083 static void compute_generation_numbers(struct write_commit_graph_context *ctx)
1084 {
1085         int i;
1086         struct commit_list *list = NULL;
1087
1088         if (ctx->report_progress)
1089                 ctx->progress = start_progress(
1090                                         _("Computing commit graph generation numbers"),
1091                                         ctx->commits.nr);
1092         for (i = 0; i < ctx->commits.nr; i++) {
1093                 display_progress(ctx->progress, i + 1);
1094                 if (ctx->commits.list[i]->generation != GENERATION_NUMBER_INFINITY &&
1095                     ctx->commits.list[i]->generation != GENERATION_NUMBER_ZERO)
1096                         continue;
1097
1098                 commit_list_insert(ctx->commits.list[i], &list);
1099                 while (list) {
1100                         struct commit *current = list->item;
1101                         struct commit_list *parent;
1102                         int all_parents_computed = 1;
1103                         uint32_t max_generation = 0;
1104
1105                         for (parent = current->parents; parent; parent = parent->next) {
1106                                 if (parent->item->generation == GENERATION_NUMBER_INFINITY ||
1107                                     parent->item->generation == GENERATION_NUMBER_ZERO) {
1108                                         all_parents_computed = 0;
1109                                         commit_list_insert(parent->item, &list);
1110                                         break;
1111                                 } else if (parent->item->generation > max_generation) {
1112                                         max_generation = parent->item->generation;
1113                                 }
1114                         }
1115
1116                         if (all_parents_computed) {
1117                                 current->generation = max_generation + 1;
1118                                 pop_commit(&list);
1119
1120                                 if (current->generation > GENERATION_NUMBER_MAX)
1121                                         current->generation = GENERATION_NUMBER_MAX;
1122                         }
1123                 }
1124         }
1125         stop_progress(&ctx->progress);
1126 }
1127
1128 static int add_ref_to_list(const char *refname,
1129                            const struct object_id *oid,
1130                            int flags, void *cb_data)
1131 {
1132         struct string_list *list = (struct string_list *)cb_data;
1133
1134         string_list_append(list, oid_to_hex(oid));
1135         return 0;
1136 }
1137
1138 int write_commit_graph_reachable(const char *obj_dir,
1139                                  enum commit_graph_write_flags flags,
1140                                  const struct split_commit_graph_opts *split_opts)
1141 {
1142         struct string_list list = STRING_LIST_INIT_DUP;
1143         int result;
1144
1145         for_each_ref(add_ref_to_list, &list);
1146         result = write_commit_graph(obj_dir, NULL, &list,
1147                                     flags, split_opts);
1148
1149         string_list_clear(&list, 0);
1150         return result;
1151 }
1152
1153 static int fill_oids_from_packs(struct write_commit_graph_context *ctx,
1154                                 struct string_list *pack_indexes)
1155 {
1156         uint32_t i;
1157         struct strbuf progress_title = STRBUF_INIT;
1158         struct strbuf packname = STRBUF_INIT;
1159         int dirlen;
1160
1161         strbuf_addf(&packname, "%s/pack/", ctx->obj_dir);
1162         dirlen = packname.len;
1163         if (ctx->report_progress) {
1164                 strbuf_addf(&progress_title,
1165                             Q_("Finding commits for commit graph in %d pack",
1166                                "Finding commits for commit graph in %d packs",
1167                                pack_indexes->nr),
1168                             pack_indexes->nr);
1169                 ctx->progress = start_delayed_progress(progress_title.buf, 0);
1170                 ctx->progress_done = 0;
1171         }
1172         for (i = 0; i < pack_indexes->nr; i++) {
1173                 struct packed_git *p;
1174                 strbuf_setlen(&packname, dirlen);
1175                 strbuf_addstr(&packname, pack_indexes->items[i].string);
1176                 p = add_packed_git(packname.buf, packname.len, 1);
1177                 if (!p) {
1178                         error(_("error adding pack %s"), packname.buf);
1179                         return -1;
1180                 }
1181                 if (open_pack_index(p)) {
1182                         error(_("error opening index for %s"), packname.buf);
1183                         return -1;
1184                 }
1185                 for_each_object_in_pack(p, add_packed_commits, ctx,
1186                                         FOR_EACH_OBJECT_PACK_ORDER);
1187                 close_pack(p);
1188                 free(p);
1189         }
1190
1191         stop_progress(&ctx->progress);
1192         strbuf_release(&progress_title);
1193         strbuf_release(&packname);
1194
1195         return 0;
1196 }
1197
1198 static int fill_oids_from_commit_hex(struct write_commit_graph_context *ctx,
1199                                      struct string_list *commit_hex)
1200 {
1201         uint32_t i;
1202         struct strbuf progress_title = STRBUF_INIT;
1203
1204         if (ctx->report_progress) {
1205                 strbuf_addf(&progress_title,
1206                             Q_("Finding commits for commit graph from %d ref",
1207                                "Finding commits for commit graph from %d refs",
1208                                commit_hex->nr),
1209                             commit_hex->nr);
1210                 ctx->progress = start_delayed_progress(
1211                                         progress_title.buf,
1212                                         commit_hex->nr);
1213         }
1214         for (i = 0; i < commit_hex->nr; i++) {
1215                 const char *end;
1216                 struct object_id oid;
1217                 struct commit *result;
1218
1219                 display_progress(ctx->progress, i + 1);
1220                 if (!parse_oid_hex(commit_hex->items[i].string, &oid, &end) &&
1221                     (result = lookup_commit_reference_gently(ctx->r, &oid, 1))) {
1222                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1223                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(result->object.oid));
1224                         ctx->oids.nr++;
1225                 } else if (ctx->check_oids) {
1226                         error(_("invalid commit object id: %s"),
1227                             commit_hex->items[i].string);
1228                         return -1;
1229                 }
1230         }
1231         stop_progress(&ctx->progress);
1232         strbuf_release(&progress_title);
1233
1234         return 0;
1235 }
1236
1237 static void fill_oids_from_all_packs(struct write_commit_graph_context *ctx)
1238 {
1239         if (ctx->report_progress)
1240                 ctx->progress = start_delayed_progress(
1241                         _("Finding commits for commit graph among packed objects"),
1242                         ctx->approx_nr_objects);
1243         for_each_packed_object(add_packed_commits, ctx,
1244                                FOR_EACH_OBJECT_PACK_ORDER);
1245         if (ctx->progress_done < ctx->approx_nr_objects)
1246                 display_progress(ctx->progress, ctx->approx_nr_objects);
1247         stop_progress(&ctx->progress);
1248 }
1249
1250 static uint32_t count_distinct_commits(struct write_commit_graph_context *ctx)
1251 {
1252         uint32_t i, count_distinct = 1;
1253
1254         if (ctx->report_progress)
1255                 ctx->progress = start_delayed_progress(
1256                         _("Counting distinct commits in commit graph"),
1257                         ctx->oids.nr);
1258         display_progress(ctx->progress, 0); /* TODO: Measure QSORT() progress */
1259         QSORT(ctx->oids.list, ctx->oids.nr, oid_compare);
1260
1261         for (i = 1; i < ctx->oids.nr; i++) {
1262                 display_progress(ctx->progress, i + 1);
1263                 if (!oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i])) {
1264                         if (ctx->split) {
1265                                 struct commit *c = lookup_commit(ctx->r, &ctx->oids.list[i]);
1266
1267                                 if (!c || c->graph_pos != COMMIT_NOT_FROM_GRAPH)
1268                                         continue;
1269                         }
1270
1271                         count_distinct++;
1272                 }
1273         }
1274         stop_progress(&ctx->progress);
1275
1276         return count_distinct;
1277 }
1278
1279 static void copy_oids_to_commits(struct write_commit_graph_context *ctx)
1280 {
1281         uint32_t i;
1282         struct commit_list *parent;
1283
1284         ctx->num_extra_edges = 0;
1285         if (ctx->report_progress)
1286                 ctx->progress = start_delayed_progress(
1287                         _("Finding extra edges in commit graph"),
1288                         ctx->oids.nr);
1289         for (i = 0; i < ctx->oids.nr; i++) {
1290                 int num_parents = 0;
1291                 display_progress(ctx->progress, i + 1);
1292                 if (i > 0 && oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i]))
1293                         continue;
1294
1295                 ALLOC_GROW(ctx->commits.list, ctx->commits.nr + 1, ctx->commits.alloc);
1296                 ctx->commits.list[ctx->commits.nr] = lookup_commit(ctx->r, &ctx->oids.list[i]);
1297
1298                 if (ctx->split &&
1299                     ctx->commits.list[ctx->commits.nr]->graph_pos != COMMIT_NOT_FROM_GRAPH)
1300                         continue;
1301
1302                 parse_commit_no_graph(ctx->commits.list[ctx->commits.nr]);
1303
1304                 for (parent = ctx->commits.list[ctx->commits.nr]->parents;
1305                      parent; parent = parent->next)
1306                         num_parents++;
1307
1308                 if (num_parents > 2)
1309                         ctx->num_extra_edges += num_parents - 1;
1310
1311                 ctx->commits.nr++;
1312         }
1313         stop_progress(&ctx->progress);
1314 }
1315
1316 static int write_graph_chunk_base_1(struct hashfile *f,
1317                                     struct commit_graph *g)
1318 {
1319         int num = 0;
1320
1321         if (!g)
1322                 return 0;
1323
1324         num = write_graph_chunk_base_1(f, g->base_graph);
1325         hashwrite(f, g->oid.hash, the_hash_algo->rawsz);
1326         return num + 1;
1327 }
1328
1329 static int write_graph_chunk_base(struct hashfile *f,
1330                                   struct write_commit_graph_context *ctx)
1331 {
1332         int num = write_graph_chunk_base_1(f, ctx->new_base_graph);
1333
1334         if (num != ctx->num_commit_graphs_after - 1) {
1335                 error(_("failed to write correct number of base graph ids"));
1336                 return -1;
1337         }
1338
1339         return 0;
1340 }
1341
1342 static int write_commit_graph_file(struct write_commit_graph_context *ctx)
1343 {
1344         uint32_t i;
1345         int fd;
1346         struct hashfile *f;
1347         struct lock_file lk = LOCK_INIT;
1348         uint32_t chunk_ids[6];
1349         uint64_t chunk_offsets[6];
1350         const unsigned hashsz = the_hash_algo->rawsz;
1351         struct strbuf progress_title = STRBUF_INIT;
1352         int num_chunks = 3;
1353         struct object_id file_hash;
1354
1355         if (ctx->split) {
1356                 struct strbuf tmp_file = STRBUF_INIT;
1357
1358                 strbuf_addf(&tmp_file,
1359                             "%s/info/commit-graphs/tmp_graph_XXXXXX",
1360                             ctx->obj_dir);
1361                 ctx->graph_name = strbuf_detach(&tmp_file, NULL);
1362         } else {
1363                 ctx->graph_name = get_commit_graph_filename(ctx->obj_dir);
1364         }
1365
1366         if (safe_create_leading_directories(ctx->graph_name)) {
1367                 UNLEAK(ctx->graph_name);
1368                 error(_("unable to create leading directories of %s"),
1369                         ctx->graph_name);
1370                 return -1;
1371         }
1372
1373         if (ctx->split) {
1374                 char *lock_name = get_chain_filename(ctx->obj_dir);
1375
1376                 hold_lock_file_for_update(&lk, lock_name, LOCK_DIE_ON_ERROR);
1377
1378                 fd = git_mkstemp_mode(ctx->graph_name, 0444);
1379                 if (fd < 0) {
1380                         error(_("unable to create '%s'"), ctx->graph_name);
1381                         return -1;
1382                 }
1383
1384                 f = hashfd(fd, ctx->graph_name);
1385         } else {
1386                 hold_lock_file_for_update(&lk, ctx->graph_name, LOCK_DIE_ON_ERROR);
1387                 fd = lk.tempfile->fd;
1388                 f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
1389         }
1390
1391         chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
1392         chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
1393         chunk_ids[2] = GRAPH_CHUNKID_DATA;
1394         if (ctx->num_extra_edges) {
1395                 chunk_ids[num_chunks] = GRAPH_CHUNKID_EXTRAEDGES;
1396                 num_chunks++;
1397         }
1398         if (ctx->num_commit_graphs_after > 1) {
1399                 chunk_ids[num_chunks] = GRAPH_CHUNKID_BASE;
1400                 num_chunks++;
1401         }
1402
1403         chunk_ids[num_chunks] = 0;
1404
1405         chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
1406         chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
1407         chunk_offsets[2] = chunk_offsets[1] + hashsz * ctx->commits.nr;
1408         chunk_offsets[3] = chunk_offsets[2] + (hashsz + 16) * ctx->commits.nr;
1409
1410         num_chunks = 3;
1411         if (ctx->num_extra_edges) {
1412                 chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
1413                                                 4 * ctx->num_extra_edges;
1414                 num_chunks++;
1415         }
1416         if (ctx->num_commit_graphs_after > 1) {
1417                 chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
1418                                                 hashsz * (ctx->num_commit_graphs_after - 1);
1419                 num_chunks++;
1420         }
1421
1422         hashwrite_be32(f, GRAPH_SIGNATURE);
1423
1424         hashwrite_u8(f, GRAPH_VERSION);
1425         hashwrite_u8(f, oid_version());
1426         hashwrite_u8(f, num_chunks);
1427         hashwrite_u8(f, ctx->num_commit_graphs_after - 1);
1428
1429         for (i = 0; i <= num_chunks; i++) {
1430                 uint32_t chunk_write[3];
1431
1432                 chunk_write[0] = htonl(chunk_ids[i]);
1433                 chunk_write[1] = htonl(chunk_offsets[i] >> 32);
1434                 chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
1435                 hashwrite(f, chunk_write, 12);
1436         }
1437
1438         if (ctx->report_progress) {
1439                 strbuf_addf(&progress_title,
1440                             Q_("Writing out commit graph in %d pass",
1441                                "Writing out commit graph in %d passes",
1442                                num_chunks),
1443                             num_chunks);
1444                 ctx->progress = start_delayed_progress(
1445                         progress_title.buf,
1446                         num_chunks * ctx->commits.nr);
1447         }
1448         write_graph_chunk_fanout(f, ctx);
1449         write_graph_chunk_oids(f, hashsz, ctx);
1450         write_graph_chunk_data(f, hashsz, ctx);
1451         if (ctx->num_extra_edges)
1452                 write_graph_chunk_extra_edges(f, ctx);
1453         if (ctx->num_commit_graphs_after > 1 &&
1454             write_graph_chunk_base(f, ctx)) {
1455                 return -1;
1456         }
1457         stop_progress(&ctx->progress);
1458         strbuf_release(&progress_title);
1459
1460         if (ctx->split && ctx->base_graph_name && ctx->num_commit_graphs_after > 1) {
1461                 char *new_base_hash = xstrdup(oid_to_hex(&ctx->new_base_graph->oid));
1462                 char *new_base_name = get_split_graph_filename(ctx->new_base_graph->obj_dir, new_base_hash);
1463
1464                 free(ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2]);
1465                 free(ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2]);
1466                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2] = new_base_name;
1467                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2] = new_base_hash;
1468         }
1469
1470         close_commit_graph(ctx->r->objects);
1471         finalize_hashfile(f, file_hash.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
1472
1473         if (ctx->split) {
1474                 FILE *chainf = fdopen_lock_file(&lk, "w");
1475                 char *final_graph_name;
1476                 int result;
1477
1478                 close(fd);
1479
1480                 if (!chainf) {
1481                         error(_("unable to open commit-graph chain file"));
1482                         return -1;
1483                 }
1484
1485                 if (ctx->base_graph_name) {
1486                         const char *dest = ctx->commit_graph_filenames_after[
1487                                                 ctx->num_commit_graphs_after - 2];
1488
1489                         if (strcmp(ctx->base_graph_name, dest)) {
1490                                 result = rename(ctx->base_graph_name, dest);
1491
1492                                 if (result) {
1493                                         error(_("failed to rename base commit-graph file"));
1494                                         return -1;
1495                                 }
1496                         }
1497                 } else {
1498                         char *graph_name = get_commit_graph_filename(ctx->obj_dir);
1499                         unlink(graph_name);
1500                 }
1501
1502                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(oid_to_hex(&file_hash));
1503                 final_graph_name = get_split_graph_filename(ctx->obj_dir,
1504                                         ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
1505                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1] = final_graph_name;
1506
1507                 result = rename(ctx->graph_name, final_graph_name);
1508
1509                 for (i = 0; i < ctx->num_commit_graphs_after; i++)
1510                         fprintf(lk.tempfile->fp, "%s\n", ctx->commit_graph_hash_after[i]);
1511
1512                 if (result) {
1513                         error(_("failed to rename temporary commit-graph file"));
1514                         return -1;
1515                 }
1516         }
1517
1518         commit_lock_file(&lk);
1519
1520         return 0;
1521 }
1522
1523 static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
1524 {
1525         struct commit_graph *g = ctx->r->objects->commit_graph;
1526         uint32_t num_commits = ctx->commits.nr;
1527         uint32_t i;
1528
1529         int max_commits = 0;
1530         int size_mult = 2;
1531
1532         if (ctx->split_opts) {
1533                 max_commits = ctx->split_opts->max_commits;
1534                 size_mult = ctx->split_opts->size_multiple;
1535         }
1536
1537         g = ctx->r->objects->commit_graph;
1538         ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1;
1539
1540         while (g && (g->num_commits <= size_mult * num_commits ||
1541                     (max_commits && num_commits > max_commits))) {
1542                 if (strcmp(g->obj_dir, ctx->obj_dir))
1543                         break;
1544
1545                 num_commits += g->num_commits;
1546                 g = g->base_graph;
1547
1548                 ctx->num_commit_graphs_after--;
1549         }
1550
1551         ctx->new_base_graph = g;
1552
1553         if (ctx->num_commit_graphs_after == 2) {
1554                 char *old_graph_name = get_commit_graph_filename(g->obj_dir);
1555
1556                 if (!strcmp(g->filename, old_graph_name) &&
1557                     strcmp(g->obj_dir, ctx->obj_dir)) {
1558                         ctx->num_commit_graphs_after = 1;
1559                         ctx->new_base_graph = NULL;
1560                 }
1561
1562                 free(old_graph_name);
1563         }
1564
1565         ALLOC_ARRAY(ctx->commit_graph_filenames_after, ctx->num_commit_graphs_after);
1566         ALLOC_ARRAY(ctx->commit_graph_hash_after, ctx->num_commit_graphs_after);
1567
1568         for (i = 0; i < ctx->num_commit_graphs_after &&
1569                     i < ctx->num_commit_graphs_before; i++)
1570                 ctx->commit_graph_filenames_after[i] = xstrdup(ctx->commit_graph_filenames_before[i]);
1571
1572         i = ctx->num_commit_graphs_before - 1;
1573         g = ctx->r->objects->commit_graph;
1574
1575         while (g) {
1576                 if (i < ctx->num_commit_graphs_after)
1577                         ctx->commit_graph_hash_after[i] = xstrdup(oid_to_hex(&g->oid));
1578
1579                 i--;
1580                 g = g->base_graph;
1581         }
1582 }
1583
1584 static void merge_commit_graph(struct write_commit_graph_context *ctx,
1585                                struct commit_graph *g)
1586 {
1587         uint32_t i;
1588         uint32_t offset = g->num_commits_in_base;
1589
1590         ALLOC_GROW(ctx->commits.list, ctx->commits.nr + g->num_commits, ctx->commits.alloc);
1591
1592         for (i = 0; i < g->num_commits; i++) {
1593                 struct object_id oid;
1594                 struct commit *result;
1595
1596                 display_progress(ctx->progress, i + 1);
1597
1598                 load_oid_from_graph(g, i + offset, &oid);
1599
1600                 /* only add commits if they still exist in the repo */
1601                 result = lookup_commit_reference_gently(ctx->r, &oid, 1);
1602
1603                 if (result) {
1604                         ctx->commits.list[ctx->commits.nr] = result;
1605                         ctx->commits.nr++;
1606                 }
1607         }
1608 }
1609
1610 static int commit_compare(const void *_a, const void *_b)
1611 {
1612         const struct commit *a = *(const struct commit **)_a;
1613         const struct commit *b = *(const struct commit **)_b;
1614         return oidcmp(&a->object.oid, &b->object.oid);
1615 }
1616
1617 static void sort_and_scan_merged_commits(struct write_commit_graph_context *ctx)
1618 {
1619         uint32_t i, num_parents;
1620         struct commit_list *parent;
1621
1622         if (ctx->report_progress)
1623                 ctx->progress = start_delayed_progress(
1624                                         _("Scanning merged commits"),
1625                                         ctx->commits.nr);
1626
1627         QSORT(ctx->commits.list, ctx->commits.nr, commit_compare);
1628
1629         ctx->num_extra_edges = 0;
1630         for (i = 0; i < ctx->commits.nr; i++) {
1631                 display_progress(ctx->progress, i);
1632
1633                 if (i && oideq(&ctx->commits.list[i - 1]->object.oid,
1634                           &ctx->commits.list[i]->object.oid)) {
1635                         die(_("unexpected duplicate commit id %s"),
1636                             oid_to_hex(&ctx->commits.list[i]->object.oid));
1637                 } else {
1638                         num_parents = 0;
1639                         for (parent = ctx->commits.list[i]->parents; parent; parent = parent->next)
1640                                 num_parents++;
1641
1642                         if (num_parents > 2)
1643                                 ctx->num_extra_edges += num_parents - 1;
1644                 }
1645         }
1646
1647         stop_progress(&ctx->progress);
1648 }
1649
1650 static void merge_commit_graphs(struct write_commit_graph_context *ctx)
1651 {
1652         struct commit_graph *g = ctx->r->objects->commit_graph;
1653         uint32_t current_graph_number = ctx->num_commit_graphs_before;
1654         struct strbuf progress_title = STRBUF_INIT;
1655
1656         while (g && current_graph_number >= ctx->num_commit_graphs_after) {
1657                 current_graph_number--;
1658
1659                 if (ctx->report_progress) {
1660                         strbuf_addstr(&progress_title, _("Merging commit-graph"));
1661                         ctx->progress = start_delayed_progress(progress_title.buf, 0);
1662                 }
1663
1664                 merge_commit_graph(ctx, g);
1665                 stop_progress(&ctx->progress);
1666                 strbuf_release(&progress_title);
1667
1668                 g = g->base_graph;
1669         }
1670
1671         if (g) {
1672                 ctx->new_base_graph = g;
1673                 ctx->new_num_commits_in_base = g->num_commits + g->num_commits_in_base;
1674         }
1675
1676         if (ctx->new_base_graph)
1677                 ctx->base_graph_name = xstrdup(ctx->new_base_graph->filename);
1678
1679         sort_and_scan_merged_commits(ctx);
1680 }
1681
1682 static void mark_commit_graphs(struct write_commit_graph_context *ctx)
1683 {
1684         uint32_t i;
1685         time_t now = time(NULL);
1686
1687         for (i = ctx->num_commit_graphs_after - 1; i < ctx->num_commit_graphs_before; i++) {
1688                 struct stat st;
1689                 struct utimbuf updated_time;
1690
1691                 stat(ctx->commit_graph_filenames_before[i], &st);
1692
1693                 updated_time.actime = st.st_atime;
1694                 updated_time.modtime = now;
1695                 utime(ctx->commit_graph_filenames_before[i], &updated_time);
1696         }
1697 }
1698
1699 static void expire_commit_graphs(struct write_commit_graph_context *ctx)
1700 {
1701         struct strbuf path = STRBUF_INIT;
1702         DIR *dir;
1703         struct dirent *de;
1704         size_t dirnamelen;
1705         timestamp_t expire_time = time(NULL);
1706
1707         if (ctx->split_opts && ctx->split_opts->expire_time)
1708                 expire_time -= ctx->split_opts->expire_time;
1709         if (!ctx->split) {
1710                 char *chain_file_name = get_chain_filename(ctx->obj_dir);
1711                 unlink(chain_file_name);
1712                 free(chain_file_name);
1713                 ctx->num_commit_graphs_after = 0;
1714         }
1715
1716         strbuf_addstr(&path, ctx->obj_dir);
1717         strbuf_addstr(&path, "/info/commit-graphs");
1718         dir = opendir(path.buf);
1719
1720         if (!dir)
1721                 goto out;
1722
1723         strbuf_addch(&path, '/');
1724         dirnamelen = path.len;
1725         while ((de = readdir(dir)) != NULL) {
1726                 struct stat st;
1727                 uint32_t i, found = 0;
1728
1729                 strbuf_setlen(&path, dirnamelen);
1730                 strbuf_addstr(&path, de->d_name);
1731
1732                 stat(path.buf, &st);
1733
1734                 if (st.st_mtime > expire_time)
1735                         continue;
1736                 if (path.len < 6 || strcmp(path.buf + path.len - 6, ".graph"))
1737                         continue;
1738
1739                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
1740                         if (!strcmp(ctx->commit_graph_filenames_after[i],
1741                                     path.buf)) {
1742                                 found = 1;
1743                                 break;
1744                         }
1745                 }
1746
1747                 if (!found)
1748                         unlink(path.buf);
1749         }
1750
1751 out:
1752         strbuf_release(&path);
1753 }
1754
1755 int write_commit_graph(const char *obj_dir,
1756                        struct string_list *pack_indexes,
1757                        struct string_list *commit_hex,
1758                        enum commit_graph_write_flags flags,
1759                        const struct split_commit_graph_opts *split_opts)
1760 {
1761         struct write_commit_graph_context *ctx;
1762         uint32_t i, count_distinct = 0;
1763         size_t len;
1764         int res = 0;
1765
1766         if (!commit_graph_compatible(the_repository))
1767                 return 0;
1768
1769         ctx = xcalloc(1, sizeof(struct write_commit_graph_context));
1770         ctx->r = the_repository;
1771
1772         /* normalize object dir with no trailing slash */
1773         ctx->obj_dir = xmallocz(strlen(obj_dir) + 1);
1774         normalize_path_copy(ctx->obj_dir, obj_dir);
1775         len = strlen(ctx->obj_dir);
1776         if (len && ctx->obj_dir[len - 1] == '/')
1777                 ctx->obj_dir[len - 1] = 0;
1778
1779         ctx->append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0;
1780         ctx->report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0;
1781         ctx->split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
1782         ctx->check_oids = flags & COMMIT_GRAPH_WRITE_CHECK_OIDS ? 1 : 0;
1783         ctx->split_opts = split_opts;
1784
1785         if (ctx->split) {
1786                 struct commit_graph *g;
1787                 prepare_commit_graph(ctx->r);
1788
1789                 g = ctx->r->objects->commit_graph;
1790
1791                 while (g) {
1792                         ctx->num_commit_graphs_before++;
1793                         g = g->base_graph;
1794                 }
1795
1796                 if (ctx->num_commit_graphs_before) {
1797                         ALLOC_ARRAY(ctx->commit_graph_filenames_before, ctx->num_commit_graphs_before);
1798                         i = ctx->num_commit_graphs_before;
1799                         g = ctx->r->objects->commit_graph;
1800
1801                         while (g) {
1802                                 ctx->commit_graph_filenames_before[--i] = xstrdup(g->filename);
1803                                 g = g->base_graph;
1804                         }
1805                 }
1806         }
1807
1808         ctx->approx_nr_objects = approximate_object_count();
1809         ctx->oids.alloc = ctx->approx_nr_objects / 32;
1810
1811         if (ctx->split && split_opts && ctx->oids.alloc > split_opts->max_commits)
1812                 ctx->oids.alloc = split_opts->max_commits;
1813
1814         if (ctx->append) {
1815                 prepare_commit_graph_one(ctx->r, ctx->obj_dir);
1816                 if (ctx->r->objects->commit_graph)
1817                         ctx->oids.alloc += ctx->r->objects->commit_graph->num_commits;
1818         }
1819
1820         if (ctx->oids.alloc < 1024)
1821                 ctx->oids.alloc = 1024;
1822         ALLOC_ARRAY(ctx->oids.list, ctx->oids.alloc);
1823
1824         if (ctx->append && ctx->r->objects->commit_graph) {
1825                 struct commit_graph *g = ctx->r->objects->commit_graph;
1826                 for (i = 0; i < g->num_commits; i++) {
1827                         const unsigned char *hash = g->chunk_oid_lookup + g->hash_len * i;
1828                         hashcpy(ctx->oids.list[ctx->oids.nr++].hash, hash);
1829                 }
1830         }
1831
1832         if (pack_indexes) {
1833                 if ((res = fill_oids_from_packs(ctx, pack_indexes)))
1834                         goto cleanup;
1835         }
1836
1837         if (commit_hex) {
1838                 if ((res = fill_oids_from_commit_hex(ctx, commit_hex)))
1839                         goto cleanup;
1840         }
1841
1842         if (!pack_indexes && !commit_hex)
1843                 fill_oids_from_all_packs(ctx);
1844
1845         close_reachable(ctx);
1846
1847         count_distinct = count_distinct_commits(ctx);
1848
1849         if (count_distinct >= GRAPH_EDGE_LAST_MASK) {
1850                 error(_("the commit graph format cannot write %d commits"), count_distinct);
1851                 res = -1;
1852                 goto cleanup;
1853         }
1854
1855         ctx->commits.alloc = count_distinct;
1856         ALLOC_ARRAY(ctx->commits.list, ctx->commits.alloc);
1857
1858         copy_oids_to_commits(ctx);
1859
1860         if (ctx->commits.nr >= GRAPH_EDGE_LAST_MASK) {
1861                 error(_("too many commits to write graph"));
1862                 res = -1;
1863                 goto cleanup;
1864         }
1865
1866         if (!ctx->commits.nr)
1867                 goto cleanup;
1868
1869         if (ctx->split) {
1870                 split_graph_merge_strategy(ctx);
1871
1872                 merge_commit_graphs(ctx);
1873         } else
1874                 ctx->num_commit_graphs_after = 1;
1875
1876         compute_generation_numbers(ctx);
1877
1878         res = write_commit_graph_file(ctx);
1879
1880         if (ctx->split)
1881                 mark_commit_graphs(ctx);
1882
1883         expire_commit_graphs(ctx);
1884
1885 cleanup:
1886         free(ctx->graph_name);
1887         free(ctx->commits.list);
1888         free(ctx->oids.list);
1889         free(ctx->obj_dir);
1890
1891         if (ctx->commit_graph_filenames_after) {
1892                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
1893                         free(ctx->commit_graph_filenames_after[i]);
1894                         free(ctx->commit_graph_hash_after[i]);
1895                 }
1896
1897                 for (i = 0; i < ctx->num_commit_graphs_before; i++)
1898                         free(ctx->commit_graph_filenames_before[i]);
1899
1900                 free(ctx->commit_graph_filenames_after);
1901                 free(ctx->commit_graph_filenames_before);
1902                 free(ctx->commit_graph_hash_after);
1903         }
1904
1905         free(ctx);
1906
1907         return res;
1908 }
1909
1910 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
1911 static int verify_commit_graph_error;
1912
1913 static void graph_report(const char *fmt, ...)
1914 {
1915         va_list ap;
1916
1917         verify_commit_graph_error = 1;
1918         va_start(ap, fmt);
1919         vfprintf(stderr, fmt, ap);
1920         fprintf(stderr, "\n");
1921         va_end(ap);
1922 }
1923
1924 #define GENERATION_ZERO_EXISTS 1
1925 #define GENERATION_NUMBER_EXISTS 2
1926
1927 int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
1928 {
1929         uint32_t i, cur_fanout_pos = 0;
1930         struct object_id prev_oid, cur_oid, checksum;
1931         int generation_zero = 0;
1932         struct hashfile *f;
1933         int devnull;
1934         struct progress *progress = NULL;
1935         int local_error = 0;
1936
1937         if (!g) {
1938                 graph_report("no commit-graph file loaded");
1939                 return 1;
1940         }
1941
1942         verify_commit_graph_error = verify_commit_graph_lite(g);
1943         if (verify_commit_graph_error)
1944                 return verify_commit_graph_error;
1945
1946         devnull = open("/dev/null", O_WRONLY);
1947         f = hashfd(devnull, NULL);
1948         hashwrite(f, g->data, g->data_len - g->hash_len);
1949         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
1950         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
1951                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
1952                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
1953         }
1954
1955         for (i = 0; i < g->num_commits; i++) {
1956                 struct commit *graph_commit;
1957
1958                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1959
1960                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
1961                         graph_report(_("commit-graph has incorrect OID order: %s then %s"),
1962                                      oid_to_hex(&prev_oid),
1963                                      oid_to_hex(&cur_oid));
1964
1965                 oidcpy(&prev_oid, &cur_oid);
1966
1967                 while (cur_oid.hash[0] > cur_fanout_pos) {
1968                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1969
1970                         if (i != fanout_value)
1971                                 graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
1972                                              cur_fanout_pos, fanout_value, i);
1973                         cur_fanout_pos++;
1974                 }
1975
1976                 graph_commit = lookup_commit(r, &cur_oid);
1977                 if (!parse_commit_in_graph_one(r, g, graph_commit))
1978                         graph_report(_("failed to parse commit %s from commit-graph"),
1979                                      oid_to_hex(&cur_oid));
1980         }
1981
1982         while (cur_fanout_pos < 256) {
1983                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1984
1985                 if (g->num_commits != fanout_value)
1986                         graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
1987                                      cur_fanout_pos, fanout_value, i);
1988
1989                 cur_fanout_pos++;
1990         }
1991
1992         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
1993                 return verify_commit_graph_error;
1994
1995         progress = start_progress(_("Verifying commits in commit graph"),
1996                                   g->num_commits);
1997         for (i = 0; i < g->num_commits; i++) {
1998                 struct commit *graph_commit, *odb_commit;
1999                 struct commit_list *graph_parents, *odb_parents;
2000                 uint32_t max_generation = 0;
2001
2002                 display_progress(progress, i + 1);
2003                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
2004
2005                 graph_commit = lookup_commit(r, &cur_oid);
2006                 odb_commit = (struct commit *)create_object(r, &cur_oid, alloc_commit_node(r));
2007                 if (parse_commit_internal(odb_commit, 0, 0)) {
2008                         graph_report(_("failed to parse commit %s from object database for commit-graph"),
2009                                      oid_to_hex(&cur_oid));
2010                         continue;
2011                 }
2012
2013                 if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
2014                            get_commit_tree_oid(odb_commit)))
2015                         graph_report(_("root tree OID for commit %s in commit-graph is %s != %s"),
2016                                      oid_to_hex(&cur_oid),
2017                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
2018                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
2019
2020                 graph_parents = graph_commit->parents;
2021                 odb_parents = odb_commit->parents;
2022
2023                 while (graph_parents) {
2024                         if (odb_parents == NULL) {
2025                                 graph_report(_("commit-graph parent list for commit %s is too long"),
2026                                              oid_to_hex(&cur_oid));
2027                                 break;
2028                         }
2029
2030                         /* parse parent in case it is in a base graph */
2031                         parse_commit_in_graph_one(r, g, graph_parents->item);
2032
2033                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
2034                                 graph_report(_("commit-graph parent for %s is %s != %s"),
2035                                              oid_to_hex(&cur_oid),
2036                                              oid_to_hex(&graph_parents->item->object.oid),
2037                                              oid_to_hex(&odb_parents->item->object.oid));
2038
2039                         if (graph_parents->item->generation > max_generation)
2040                                 max_generation = graph_parents->item->generation;
2041
2042                         graph_parents = graph_parents->next;
2043                         odb_parents = odb_parents->next;
2044                 }
2045
2046                 if (odb_parents != NULL)
2047                         graph_report(_("commit-graph parent list for commit %s terminates early"),
2048                                      oid_to_hex(&cur_oid));
2049
2050                 if (!graph_commit->generation) {
2051                         if (generation_zero == GENERATION_NUMBER_EXISTS)
2052                                 graph_report(_("commit-graph has generation number zero for commit %s, but non-zero elsewhere"),
2053                                              oid_to_hex(&cur_oid));
2054                         generation_zero = GENERATION_ZERO_EXISTS;
2055                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
2056                         graph_report(_("commit-graph has non-zero generation number for commit %s, but zero elsewhere"),
2057                                      oid_to_hex(&cur_oid));
2058
2059                 if (generation_zero == GENERATION_ZERO_EXISTS)
2060                         continue;
2061
2062                 /*
2063                  * If one of our parents has generation GENERATION_NUMBER_MAX, then
2064                  * our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
2065                  * extra logic in the following condition.
2066                  */
2067                 if (max_generation == GENERATION_NUMBER_MAX)
2068                         max_generation--;
2069
2070                 if (graph_commit->generation != max_generation + 1)
2071                         graph_report(_("commit-graph generation for commit %s is %u != %u"),
2072                                      oid_to_hex(&cur_oid),
2073                                      graph_commit->generation,
2074                                      max_generation + 1);
2075
2076                 if (graph_commit->date != odb_commit->date)
2077                         graph_report(_("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime),
2078                                      oid_to_hex(&cur_oid),
2079                                      graph_commit->date,
2080                                      odb_commit->date);
2081         }
2082         stop_progress(&progress);
2083
2084         local_error = verify_commit_graph_error;
2085
2086         if (!(flags & COMMIT_GRAPH_VERIFY_SHALLOW) && g->base_graph)
2087                 local_error |= verify_commit_graph(r, g->base_graph, flags);
2088
2089         return local_error;
2090 }
2091
2092 void free_commit_graph(struct commit_graph *g)
2093 {
2094         if (!g)
2095                 return;
2096         if (g->graph_fd >= 0) {
2097                 munmap((void *)g->data, g->data_len);
2098                 g->data = NULL;
2099                 close(g->graph_fd);
2100         }
2101         free(g->filename);
2102         free(g);
2103 }