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 attempts 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                 hashwrite(f, tree->hash, hash_len);
 862
 863                 parent = (*list)->parents;
 864
 865                 if (!parent)
 866                         edge_value = GRAPH_PARENT_NONE;
 867                 else {
 868                         edge_value = sha1_pos(parent->item->object.oid.hash,
 869                                               ctx->commits.list,
 870                                               ctx->commits.nr,
 871                                               commit_to_sha1);
 872
 873                         if (edge_value >= 0)
 874                                 edge_value += ctx->new_num_commits_in_base;
 875                         else {
 876                                 uint32_t pos;
 877                                 if (find_commit_in_graph(parent->item,
 878                                                          ctx->new_base_graph,
 879                                                          &pos))
 880                                         edge_value = pos;
 881                         }
 882
 883                         if (edge_value < 0)
 884                                 BUG("missing parent %s for commit %s",
 885                                     oid_to_hex(&parent->item->object.oid),
 886                                     oid_to_hex(&(*list)->object.oid));
 887                 }
 888
 889                 hashwrite_be32(f, edge_value);
 890
 891                 if (parent)
 892                         parent = parent->next;
 893
 894                 if (!parent)
 895                         edge_value = GRAPH_PARENT_NONE;
 896                 else if (parent->next)
 897                         edge_value = GRAPH_EXTRA_EDGES_NEEDED | num_extra_edges;
 898                 else {
 899                         edge_value = sha1_pos(parent->item->object.oid.hash,
 900                                               ctx->commits.list,
 901                                               ctx->commits.nr,
 902                                               commit_to_sha1);
 903
 904                         if (edge_value >= 0)
 905                                 edge_value += ctx->new_num_commits_in_base;
 906                         else {
 907                                 uint32_t pos;
 908                                 if (find_commit_in_graph(parent->item,
 909                                                          ctx->new_base_graph,
 910                                                          &pos))
 911                                         edge_value = pos;
 912                         }
 913
 914                         if (edge_value < 0)
 915                                 BUG("missing parent %s for commit %s",
 916                                     oid_to_hex(&parent->item->object.oid),
 917                                     oid_to_hex(&(*list)->object.oid));
 918                 }
 919
 920                 hashwrite_be32(f, edge_value);
 921
 922                 if (edge_value & GRAPH_EXTRA_EDGES_NEEDED) {
 923                         do {
 924                                 num_extra_edges++;
 925                                 parent = parent->next;
 926                         } while (parent);
 927                 }
 928
 929                 if (sizeof((*list)->date) > 4)
 930                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
 931                 else
 932                         packedDate[0] = 0;
 933
 934                 packedDate[0] |= htonl((*list)->generation << 2);
 935
 936                 packedDate[1] = htonl((*list)->date);
 937                 hashwrite(f, packedDate, 8);
 938
 939                 list++;
 940         }
 941 }
 942
 943 static void write_graph_chunk_extra_edges(struct hashfile *f,
 944                                           struct write_commit_graph_context *ctx)
 945 {
 946         struct commit **list = ctx->commits.list;
 947         struct commit **last = ctx->commits.list + ctx->commits.nr;
 948         struct commit_list *parent;
 949
 950         while (list < last) {
 951                 int num_parents = 0;
 952
 953                 display_progress(ctx->progress, ++ctx->progress_cnt);
 954
 955                 for (parent = (*list)->parents; num_parents < 3 && parent;
 956                      parent = parent->next)
 957                         num_parents++;
 958
 959                 if (num_parents <= 2) {
 960                         list++;
 961                         continue;
 962                 }
 963
 964                 /* Since num_parents > 2, this initializer is safe. */
 965                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
 966                         int edge_value = sha1_pos(parent->item->object.oid.hash,
 967                                                   ctx->commits.list,
 968                                                   ctx->commits.nr,
 969                                                   commit_to_sha1);
 970
 971                         if (edge_value >= 0)
 972                                 edge_value += ctx->new_num_commits_in_base;
 973                         else {
 974                                 uint32_t pos;
 975                                 if (find_commit_in_graph(parent->item,
 976                                                          ctx->new_base_graph,
 977                                                          &pos))
 978                                         edge_value = pos;
 979                         }
 980
 981                         if (edge_value < 0)
 982                                 BUG("missing parent %s for commit %s",
 983                                     oid_to_hex(&parent->item->object.oid),
 984                                     oid_to_hex(&(*list)->object.oid));
 985                         else if (!parent->next)
 986                                 edge_value |= GRAPH_LAST_EDGE;
 987
 988                         hashwrite_be32(f, edge_value);
 989                 }
 990
 991                 list++;
 992         }
 993 }
 994
 995 static int oid_compare(const void *_a, const void *_b)
 996 {
 997         const struct object_id *a = (const struct object_id *)_a;
 998         const struct object_id *b = (const struct object_id *)_b;
 999         return oidcmp(a, b);
1000 }
1001
1002 static int add_packed_commits(const struct object_id *oid,
1003                               struct packed_git *pack,
1004                               uint32_t pos,
1005                               void *data)
1006 {
1007         struct write_commit_graph_context *ctx = (struct write_commit_graph_context*)data;
1008         enum object_type type;
1009         off_t offset = nth_packed_object_offset(pack, pos);
1010         struct object_info oi = OBJECT_INFO_INIT;
1011
1012         if (ctx->progress)
1013                 display_progress(ctx->progress, ++ctx->progress_done);
1014
1015         oi.typep = &type;
1016         if (packed_object_info(ctx->r, pack, offset, &oi) < 0)
1017                 die(_("unable to get type of object %s"), oid_to_hex(oid));
1018
1019         if (type != OBJ_COMMIT)
1020                 return 0;
1021
1022         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1023         oidcpy(&(ctx->oids.list[ctx->oids.nr]), oid);
1024         ctx->oids.nr++;
1025
1026         return 0;
1027 }
1028
1029 static void add_missing_parents(struct write_commit_graph_context *ctx, struct commit *commit)
1030 {
1031         struct commit_list *parent;
1032         for (parent = commit->parents; parent; parent = parent->next) {
1033                 if (!(parent->item->object.flags & REACHABLE)) {
1034                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1035                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(parent->item->object.oid));
1036                         ctx->oids.nr++;
1037                         parent->item->object.flags |= REACHABLE;
1038                 }
1039         }
1040 }
1041
1042 static void close_reachable(struct write_commit_graph_context *ctx)
1043 {
1044         int i;
1045         struct commit *commit;
1046
1047         if (ctx->report_progress)
1048                 ctx->progress = start_delayed_progress(
1049                                         _("Loading known commits in commit graph"),
1050                                         ctx->oids.nr);
1051         for (i = 0; i < ctx->oids.nr; i++) {
1052                 display_progress(ctx->progress, i + 1);
1053                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1054                 if (commit)
1055                         commit->object.flags |= REACHABLE;
1056         }
1057         stop_progress(&ctx->progress);
1058
1059         /*
1060          * As this loop runs, ctx->oids.nr may grow, but not more
1061          * than the number of missing commits in the reachable
1062          * closure.
1063          */
1064         if (ctx->report_progress)
1065                 ctx->progress = start_delayed_progress(
1066                                         _("Expanding reachable commits in commit graph"),
1067                                         0);
1068         for (i = 0; i < ctx->oids.nr; i++) {
1069                 display_progress(ctx->progress, i + 1);
1070                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1071
1072                 if (!commit)
1073                         continue;
1074                 if (ctx->split) {
1075                         if (!parse_commit(commit) &&
1076                             commit->graph_pos == COMMIT_NOT_FROM_GRAPH)
1077                                 add_missing_parents(ctx, commit);
1078                 } else if (!parse_commit_no_graph(commit))
1079                         add_missing_parents(ctx, commit);
1080         }
1081         stop_progress(&ctx->progress);
1082
1083         if (ctx->report_progress)
1084                 ctx->progress = start_delayed_progress(
1085                                         _("Clearing commit marks in commit graph"),
1086                                         ctx->oids.nr);
1087         for (i = 0; i < ctx->oids.nr; i++) {
1088                 display_progress(ctx->progress, i + 1);
1089                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1090
1091                 if (commit)
1092                         commit->object.flags &= ~REACHABLE;
1093         }
1094         stop_progress(&ctx->progress);
1095 }
1096
1097 static void compute_generation_numbers(struct write_commit_graph_context *ctx)
1098 {
1099         int i;
1100         struct commit_list *list = NULL;
1101
1102         if (ctx->report_progress)
1103                 ctx->progress = start_delayed_progress(
1104                                         _("Computing commit graph generation numbers"),
1105                                         ctx->commits.nr);
1106         for (i = 0; i < ctx->commits.nr; i++) {
1107                 display_progress(ctx->progress, i + 1);
1108                 if (ctx->commits.list[i]->generation != GENERATION_NUMBER_INFINITY &&
1109                     ctx->commits.list[i]->generation != GENERATION_NUMBER_ZERO)
1110                         continue;
1111
1112                 commit_list_insert(ctx->commits.list[i], &list);
1113                 while (list) {
1114                         struct commit *current = list->item;
1115                         struct commit_list *parent;
1116                         int all_parents_computed = 1;
1117                         uint32_t max_generation = 0;
1118
1119                         for (parent = current->parents; parent; parent = parent->next) {
1120                                 if (parent->item->generation == GENERATION_NUMBER_INFINITY ||
1121                                     parent->item->generation == GENERATION_NUMBER_ZERO) {
1122                                         all_parents_computed = 0;
1123                                         commit_list_insert(parent->item, &list);
1124                                         break;
1125                                 } else if (parent->item->generation > max_generation) {
1126                                         max_generation = parent->item->generation;
1127                                 }
1128                         }
1129
1130                         if (all_parents_computed) {
1131                                 current->generation = max_generation + 1;
1132                                 pop_commit(&list);
1133
1134                                 if (current->generation > GENERATION_NUMBER_MAX)
1135                                         current->generation = GENERATION_NUMBER_MAX;
1136                         }
1137                 }
1138         }
1139         stop_progress(&ctx->progress);
1140 }
1141
1142 static int add_ref_to_list(const char *refname,
1143                            const struct object_id *oid,
1144                            int flags, void *cb_data)
1145 {
1146         struct string_list *list = (struct string_list *)cb_data;
1147
1148         string_list_append(list, oid_to_hex(oid));
1149         return 0;
1150 }
1151
1152 int write_commit_graph_reachable(const char *obj_dir,
1153                                  enum commit_graph_write_flags flags,
1154                                  const struct split_commit_graph_opts *split_opts)
1155 {
1156         struct string_list list = STRING_LIST_INIT_DUP;
1157         int result;
1158
1159         for_each_ref(add_ref_to_list, &list);
1160         result = write_commit_graph(obj_dir, NULL, &list,
1161                                     flags, split_opts);
1162
1163         string_list_clear(&list, 0);
1164         return result;
1165 }
1166
1167 static int fill_oids_from_packs(struct write_commit_graph_context *ctx,
1168                                 struct string_list *pack_indexes)
1169 {
1170         uint32_t i;
1171         struct strbuf progress_title = STRBUF_INIT;
1172         struct strbuf packname = STRBUF_INIT;
1173         int dirlen;
1174
1175         strbuf_addf(&packname, "%s/pack/", ctx->obj_dir);
1176         dirlen = packname.len;
1177         if (ctx->report_progress) {
1178                 strbuf_addf(&progress_title,
1179                             Q_("Finding commits for commit graph in %d pack",
1180                                "Finding commits for commit graph in %d packs",
1181                                pack_indexes->nr),
1182                             pack_indexes->nr);
1183                 ctx->progress = start_delayed_progress(progress_title.buf, 0);
1184                 ctx->progress_done = 0;
1185         }
1186         for (i = 0; i < pack_indexes->nr; i++) {
1187                 struct packed_git *p;
1188                 strbuf_setlen(&packname, dirlen);
1189                 strbuf_addstr(&packname, pack_indexes->items[i].string);
1190                 p = add_packed_git(packname.buf, packname.len, 1);
1191                 if (!p) {
1192                         error(_("error adding pack %s"), packname.buf);
1193                         return -1;
1194                 }
1195                 if (open_pack_index(p)) {
1196                         error(_("error opening index for %s"), packname.buf);
1197                         return -1;
1198                 }
1199                 for_each_object_in_pack(p, add_packed_commits, ctx,
1200                                         FOR_EACH_OBJECT_PACK_ORDER);
1201                 close_pack(p);
1202                 free(p);
1203         }
1204
1205         stop_progress(&ctx->progress);
1206         strbuf_release(&progress_title);
1207         strbuf_release(&packname);
1208
1209         return 0;
1210 }
1211
1212 static int fill_oids_from_commit_hex(struct write_commit_graph_context *ctx,
1213                                      struct string_list *commit_hex)
1214 {
1215         uint32_t i;
1216         struct strbuf progress_title = STRBUF_INIT;
1217
1218         if (ctx->report_progress) {
1219                 strbuf_addf(&progress_title,
1220                             Q_("Finding commits for commit graph from %d ref",
1221                                "Finding commits for commit graph from %d refs",
1222                                commit_hex->nr),
1223                             commit_hex->nr);
1224                 ctx->progress = start_delayed_progress(
1225                                         progress_title.buf,
1226                                         commit_hex->nr);
1227         }
1228         for (i = 0; i < commit_hex->nr; i++) {
1229                 const char *end;
1230                 struct object_id oid;
1231                 struct commit *result;
1232
1233                 display_progress(ctx->progress, i + 1);
1234                 if (!parse_oid_hex(commit_hex->items[i].string, &oid, &end) &&
1235                     (result = lookup_commit_reference_gently(ctx->r, &oid, 1))) {
1236                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1237                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(result->object.oid));
1238                         ctx->oids.nr++;
1239                 } else if (ctx->check_oids) {
1240                         error(_("invalid commit object id: %s"),
1241                             commit_hex->items[i].string);
1242                         return -1;
1243                 }
1244         }
1245         stop_progress(&ctx->progress);
1246         strbuf_release(&progress_title);
1247
1248         return 0;
1249 }
1250
1251 static void fill_oids_from_all_packs(struct write_commit_graph_context *ctx)
1252 {
1253         if (ctx->report_progress)
1254                 ctx->progress = start_delayed_progress(
1255                         _("Finding commits for commit graph among packed objects"),
1256                         ctx->approx_nr_objects);
1257         for_each_packed_object(add_packed_commits, ctx,
1258                                FOR_EACH_OBJECT_PACK_ORDER);
1259         if (ctx->progress_done < ctx->approx_nr_objects)
1260                 display_progress(ctx->progress, ctx->approx_nr_objects);
1261         stop_progress(&ctx->progress);
1262 }
1263
1264 static uint32_t count_distinct_commits(struct write_commit_graph_context *ctx)
1265 {
1266         uint32_t i, count_distinct = 1;
1267
1268         if (ctx->report_progress)
1269                 ctx->progress = start_delayed_progress(
1270                         _("Counting distinct commits in commit graph"),
1271                         ctx->oids.nr);
1272         display_progress(ctx->progress, 0); /* TODO: Measure QSORT() progress */
1273         QSORT(ctx->oids.list, ctx->oids.nr, oid_compare);
1274
1275         for (i = 1; i < ctx->oids.nr; i++) {
1276                 display_progress(ctx->progress, i + 1);
1277                 if (!oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i])) {
1278                         if (ctx->split) {
1279                                 struct commit *c = lookup_commit(ctx->r, &ctx->oids.list[i]);
1280
1281                                 if (!c || c->graph_pos != COMMIT_NOT_FROM_GRAPH)
1282                                         continue;
1283                         }
1284
1285                         count_distinct++;
1286                 }
1287         }
1288         stop_progress(&ctx->progress);
1289
1290         return count_distinct;
1291 }
1292
1293 static void copy_oids_to_commits(struct write_commit_graph_context *ctx)
1294 {
1295         uint32_t i;
1296
1297         ctx->num_extra_edges = 0;
1298         if (ctx->report_progress)
1299                 ctx->progress = start_delayed_progress(
1300                         _("Finding extra edges in commit graph"),
1301                         ctx->oids.nr);
1302         for (i = 0; i < ctx->oids.nr; i++) {
1303                 unsigned int num_parents;
1304
1305                 display_progress(ctx->progress, i + 1);
1306                 if (i > 0 && oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i]))
1307                         continue;
1308
1309                 ALLOC_GROW(ctx->commits.list, ctx->commits.nr + 1, ctx->commits.alloc);
1310                 ctx->commits.list[ctx->commits.nr] = lookup_commit(ctx->r, &ctx->oids.list[i]);
1311
1312                 if (ctx->split &&
1313                     ctx->commits.list[ctx->commits.nr]->graph_pos != COMMIT_NOT_FROM_GRAPH)
1314                         continue;
1315
1316                 parse_commit_no_graph(ctx->commits.list[ctx->commits.nr]);
1317
1318                 num_parents = commit_list_count(ctx->commits.list[ctx->commits.nr]->parents);
1319                 if (num_parents > 2)
1320                         ctx->num_extra_edges += num_parents - 1;
1321
1322                 ctx->commits.nr++;
1323         }
1324         stop_progress(&ctx->progress);
1325 }
1326
1327 static int write_graph_chunk_base_1(struct hashfile *f,
1328                                     struct commit_graph *g)
1329 {
1330         int num = 0;
1331
1332         if (!g)
1333                 return 0;
1334
1335         num = write_graph_chunk_base_1(f, g->base_graph);
1336         hashwrite(f, g->oid.hash, the_hash_algo->rawsz);
1337         return num + 1;
1338 }
1339
1340 static int write_graph_chunk_base(struct hashfile *f,
1341                                   struct write_commit_graph_context *ctx)
1342 {
1343         int num = write_graph_chunk_base_1(f, ctx->new_base_graph);
1344
1345         if (num != ctx->num_commit_graphs_after - 1) {
1346                 error(_("failed to write correct number of base graph ids"));
1347                 return -1;
1348         }
1349
1350         return 0;
1351 }
1352
1353 static int write_commit_graph_file(struct write_commit_graph_context *ctx)
1354 {
1355         uint32_t i;
1356         int fd;
1357         struct hashfile *f;
1358         struct lock_file lk = LOCK_INIT;
1359         uint32_t chunk_ids[6];
1360         uint64_t chunk_offsets[6];
1361         const unsigned hashsz = the_hash_algo->rawsz;
1362         struct strbuf progress_title = STRBUF_INIT;
1363         int num_chunks = 3;
1364         struct object_id file_hash;
1365
1366         if (ctx->split) {
1367                 struct strbuf tmp_file = STRBUF_INIT;
1368
1369                 strbuf_addf(&tmp_file,
1370                             "%s/info/commit-graphs/tmp_graph_XXXXXX",
1371                             ctx->obj_dir);
1372                 ctx->graph_name = strbuf_detach(&tmp_file, NULL);
1373         } else {
1374                 ctx->graph_name = get_commit_graph_filename(ctx->obj_dir);
1375         }
1376
1377         if (safe_create_leading_directories(ctx->graph_name)) {
1378                 UNLEAK(ctx->graph_name);
1379                 error(_("unable to create leading directories of %s"),
1380                         ctx->graph_name);
1381                 return -1;
1382         }
1383
1384         if (ctx->split) {
1385                 char *lock_name = get_chain_filename(ctx->obj_dir);
1386
1387                 hold_lock_file_for_update(&lk, lock_name, LOCK_DIE_ON_ERROR);
1388
1389                 fd = git_mkstemp_mode(ctx->graph_name, 0444);
1390                 if (fd < 0) {
1391                         error(_("unable to create '%s'"), ctx->graph_name);
1392                         return -1;
1393                 }
1394
1395                 f = hashfd(fd, ctx->graph_name);
1396         } else {
1397                 hold_lock_file_for_update(&lk, ctx->graph_name, LOCK_DIE_ON_ERROR);
1398                 fd = lk.tempfile->fd;
1399                 f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
1400         }
1401
1402         chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
1403         chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
1404         chunk_ids[2] = GRAPH_CHUNKID_DATA;
1405         if (ctx->num_extra_edges) {
1406                 chunk_ids[num_chunks] = GRAPH_CHUNKID_EXTRAEDGES;
1407                 num_chunks++;
1408         }
1409         if (ctx->num_commit_graphs_after > 1) {
1410                 chunk_ids[num_chunks] = GRAPH_CHUNKID_BASE;
1411                 num_chunks++;
1412         }
1413
1414         chunk_ids[num_chunks] = 0;
1415
1416         chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
1417         chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
1418         chunk_offsets[2] = chunk_offsets[1] + hashsz * ctx->commits.nr;
1419         chunk_offsets[3] = chunk_offsets[2] + (hashsz + 16) * ctx->commits.nr;
1420
1421         num_chunks = 3;
1422         if (ctx->num_extra_edges) {
1423                 chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
1424                                                 4 * ctx->num_extra_edges;
1425                 num_chunks++;
1426         }
1427         if (ctx->num_commit_graphs_after > 1) {
1428                 chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
1429                                                 hashsz * (ctx->num_commit_graphs_after - 1);
1430                 num_chunks++;
1431         }
1432
1433         hashwrite_be32(f, GRAPH_SIGNATURE);
1434
1435         hashwrite_u8(f, GRAPH_VERSION);
1436         hashwrite_u8(f, oid_version());
1437         hashwrite_u8(f, num_chunks);
1438         hashwrite_u8(f, ctx->num_commit_graphs_after - 1);
1439
1440         for (i = 0; i <= num_chunks; i++) {
1441                 uint32_t chunk_write[3];
1442
1443                 chunk_write[0] = htonl(chunk_ids[i]);
1444                 chunk_write[1] = htonl(chunk_offsets[i] >> 32);
1445                 chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
1446                 hashwrite(f, chunk_write, 12);
1447         }
1448
1449         if (ctx->report_progress) {
1450                 strbuf_addf(&progress_title,
1451                             Q_("Writing out commit graph in %d pass",
1452                                "Writing out commit graph in %d passes",
1453                                num_chunks),
1454                             num_chunks);
1455                 ctx->progress = start_delayed_progress(
1456                         progress_title.buf,
1457                         num_chunks * ctx->commits.nr);
1458         }
1459         write_graph_chunk_fanout(f, ctx);
1460         write_graph_chunk_oids(f, hashsz, ctx);
1461         write_graph_chunk_data(f, hashsz, ctx);
1462         if (ctx->num_extra_edges)
1463                 write_graph_chunk_extra_edges(f, ctx);
1464         if (ctx->num_commit_graphs_after > 1 &&
1465             write_graph_chunk_base(f, ctx)) {
1466                 return -1;
1467         }
1468         stop_progress(&ctx->progress);
1469         strbuf_release(&progress_title);
1470
1471         if (ctx->split && ctx->base_graph_name && ctx->num_commit_graphs_after > 1) {
1472                 char *new_base_hash = xstrdup(oid_to_hex(&ctx->new_base_graph->oid));
1473                 char *new_base_name = get_split_graph_filename(ctx->new_base_graph->obj_dir, new_base_hash);
1474
1475                 free(ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2]);
1476                 free(ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2]);
1477                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2] = new_base_name;
1478                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2] = new_base_hash;
1479         }
1480
1481         close_commit_graph(ctx->r->objects);
1482         finalize_hashfile(f, file_hash.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
1483
1484         if (ctx->split) {
1485                 FILE *chainf = fdopen_lock_file(&lk, "w");
1486                 char *final_graph_name;
1487                 int result;
1488
1489                 close(fd);
1490
1491                 if (!chainf) {
1492                         error(_("unable to open commit-graph chain file"));
1493                         return -1;
1494                 }
1495
1496                 if (ctx->base_graph_name) {
1497                         const char *dest = ctx->commit_graph_filenames_after[
1498                                                 ctx->num_commit_graphs_after - 2];
1499
1500                         if (strcmp(ctx->base_graph_name, dest)) {
1501                                 result = rename(ctx->base_graph_name, dest);
1502
1503                                 if (result) {
1504                                         error(_("failed to rename base commit-graph file"));
1505                                         return -1;
1506                                 }
1507                         }
1508                 } else {
1509                         char *graph_name = get_commit_graph_filename(ctx->obj_dir);
1510                         unlink(graph_name);
1511                 }
1512
1513                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(oid_to_hex(&file_hash));
1514                 final_graph_name = get_split_graph_filename(ctx->obj_dir,
1515                                         ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
1516                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1] = final_graph_name;
1517
1518                 result = rename(ctx->graph_name, final_graph_name);
1519
1520                 for (i = 0; i < ctx->num_commit_graphs_after; i++)
1521                         fprintf(lk.tempfile->fp, "%s\n", ctx->commit_graph_hash_after[i]);
1522
1523                 if (result) {
1524                         error(_("failed to rename temporary commit-graph file"));
1525                         return -1;
1526                 }
1527         }
1528
1529         commit_lock_file(&lk);
1530
1531         return 0;
1532 }
1533
1534 static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
1535 {
1536         struct commit_graph *g;
1537         uint32_t num_commits;
1538         uint32_t i;
1539
1540         int max_commits = 0;
1541         int size_mult = 2;
1542
1543         if (ctx->split_opts) {
1544                 max_commits = ctx->split_opts->max_commits;
1545
1546                 if (ctx->split_opts->size_multiple)
1547                         size_mult = ctx->split_opts->size_multiple;
1548         }
1549
1550         g = ctx->r->objects->commit_graph;
1551         num_commits = ctx->commits.nr;
1552         ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1;
1553
1554         while (g && (g->num_commits <= size_mult * num_commits ||
1555                     (max_commits && num_commits > max_commits))) {
1556                 if (strcmp(g->obj_dir, ctx->obj_dir))
1557                         break;
1558
1559                 num_commits += g->num_commits;
1560                 g = g->base_graph;
1561
1562                 ctx->num_commit_graphs_after--;
1563         }
1564
1565         ctx->new_base_graph = g;
1566
1567         if (ctx->num_commit_graphs_after == 2) {
1568                 char *old_graph_name = get_commit_graph_filename(g->obj_dir);
1569
1570                 if (!strcmp(g->filename, old_graph_name) &&
1571                     strcmp(g->obj_dir, ctx->obj_dir)) {
1572                         ctx->num_commit_graphs_after = 1;
1573                         ctx->new_base_graph = NULL;
1574                 }
1575
1576                 free(old_graph_name);
1577         }
1578
1579         ALLOC_ARRAY(ctx->commit_graph_filenames_after, ctx->num_commit_graphs_after);
1580         ALLOC_ARRAY(ctx->commit_graph_hash_after, ctx->num_commit_graphs_after);
1581
1582         for (i = 0; i < ctx->num_commit_graphs_after &&
1583                     i < ctx->num_commit_graphs_before; i++)
1584                 ctx->commit_graph_filenames_after[i] = xstrdup(ctx->commit_graph_filenames_before[i]);
1585
1586         i = ctx->num_commit_graphs_before - 1;
1587         g = ctx->r->objects->commit_graph;
1588
1589         while (g) {
1590                 if (i < ctx->num_commit_graphs_after)
1591                         ctx->commit_graph_hash_after[i] = xstrdup(oid_to_hex(&g->oid));
1592
1593                 i--;
1594                 g = g->base_graph;
1595         }
1596 }
1597
1598 static void merge_commit_graph(struct write_commit_graph_context *ctx,
1599                                struct commit_graph *g)
1600 {
1601         uint32_t i;
1602         uint32_t offset = g->num_commits_in_base;
1603
1604         ALLOC_GROW(ctx->commits.list, ctx->commits.nr + g->num_commits, ctx->commits.alloc);
1605
1606         for (i = 0; i < g->num_commits; i++) {
1607                 struct object_id oid;
1608                 struct commit *result;
1609
1610                 display_progress(ctx->progress, i + 1);
1611
1612                 load_oid_from_graph(g, i + offset, &oid);
1613
1614                 /* only add commits if they still exist in the repo */
1615                 result = lookup_commit_reference_gently(ctx->r, &oid, 1);
1616
1617                 if (result) {
1618                         ctx->commits.list[ctx->commits.nr] = result;
1619                         ctx->commits.nr++;
1620                 }
1621         }
1622 }
1623
1624 static int commit_compare(const void *_a, const void *_b)
1625 {
1626         const struct commit *a = *(const struct commit **)_a;
1627         const struct commit *b = *(const struct commit **)_b;
1628         return oidcmp(&a->object.oid, &b->object.oid);
1629 }
1630
1631 static void sort_and_scan_merged_commits(struct write_commit_graph_context *ctx)
1632 {
1633         uint32_t i;
1634
1635         if (ctx->report_progress)
1636                 ctx->progress = start_delayed_progress(
1637                                         _("Scanning merged commits"),
1638                                         ctx->commits.nr);
1639
1640         QSORT(ctx->commits.list, ctx->commits.nr, commit_compare);
1641
1642         ctx->num_extra_edges = 0;
1643         for (i = 0; i < ctx->commits.nr; i++) {
1644                 display_progress(ctx->progress, i);
1645
1646                 if (i && oideq(&ctx->commits.list[i - 1]->object.oid,
1647                           &ctx->commits.list[i]->object.oid)) {
1648                         die(_("unexpected duplicate commit id %s"),
1649                             oid_to_hex(&ctx->commits.list[i]->object.oid));
1650                 } else {
1651                         unsigned int num_parents;
1652
1653                         num_parents = commit_list_count(ctx->commits.list[i]->parents);
1654                         if (num_parents > 2)
1655                                 ctx->num_extra_edges += num_parents - 1;
1656                 }
1657         }
1658
1659         stop_progress(&ctx->progress);
1660 }
1661
1662 static void merge_commit_graphs(struct write_commit_graph_context *ctx)
1663 {
1664         struct commit_graph *g = ctx->r->objects->commit_graph;
1665         uint32_t current_graph_number = ctx->num_commit_graphs_before;
1666         struct strbuf progress_title = STRBUF_INIT;
1667
1668         while (g && current_graph_number >= ctx->num_commit_graphs_after) {
1669                 current_graph_number--;
1670
1671                 if (ctx->report_progress) {
1672                         strbuf_addstr(&progress_title, _("Merging commit-graph"));
1673                         ctx->progress = start_delayed_progress(progress_title.buf, 0);
1674                 }
1675
1676                 merge_commit_graph(ctx, g);
1677                 stop_progress(&ctx->progress);
1678                 strbuf_release(&progress_title);
1679
1680                 g = g->base_graph;
1681         }
1682
1683         if (g) {
1684                 ctx->new_base_graph = g;
1685                 ctx->new_num_commits_in_base = g->num_commits + g->num_commits_in_base;
1686         }
1687
1688         if (ctx->new_base_graph)
1689                 ctx->base_graph_name = xstrdup(ctx->new_base_graph->filename);
1690
1691         sort_and_scan_merged_commits(ctx);
1692 }
1693
1694 static void mark_commit_graphs(struct write_commit_graph_context *ctx)
1695 {
1696         uint32_t i;
1697         time_t now = time(NULL);
1698
1699         for (i = ctx->num_commit_graphs_after - 1; i < ctx->num_commit_graphs_before; i++) {
1700                 struct stat st;
1701                 struct utimbuf updated_time;
1702
1703                 stat(ctx->commit_graph_filenames_before[i], &st);
1704
1705                 updated_time.actime = st.st_atime;
1706                 updated_time.modtime = now;
1707                 utime(ctx->commit_graph_filenames_before[i], &updated_time);
1708         }
1709 }
1710
1711 static void expire_commit_graphs(struct write_commit_graph_context *ctx)
1712 {
1713         struct strbuf path = STRBUF_INIT;
1714         DIR *dir;
1715         struct dirent *de;
1716         size_t dirnamelen;
1717         timestamp_t expire_time = time(NULL);
1718
1719         if (ctx->split_opts && ctx->split_opts->expire_time)
1720                 expire_time -= ctx->split_opts->expire_time;
1721         if (!ctx->split) {
1722                 char *chain_file_name = get_chain_filename(ctx->obj_dir);
1723                 unlink(chain_file_name);
1724                 free(chain_file_name);
1725                 ctx->num_commit_graphs_after = 0;
1726         }
1727
1728         strbuf_addstr(&path, ctx->obj_dir);
1729         strbuf_addstr(&path, "/info/commit-graphs");
1730         dir = opendir(path.buf);
1731
1732         if (!dir)
1733                 goto out;
1734
1735         strbuf_addch(&path, '/');
1736         dirnamelen = path.len;
1737         while ((de = readdir(dir)) != NULL) {
1738                 struct stat st;
1739                 uint32_t i, found = 0;
1740
1741                 strbuf_setlen(&path, dirnamelen);
1742                 strbuf_addstr(&path, de->d_name);
1743
1744                 stat(path.buf, &st);
1745
1746                 if (st.st_mtime > expire_time)
1747                         continue;
1748                 if (path.len < 6 || strcmp(path.buf + path.len - 6, ".graph"))
1749                         continue;
1750
1751                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
1752                         if (!strcmp(ctx->commit_graph_filenames_after[i],
1753                                     path.buf)) {
1754                                 found = 1;
1755                                 break;
1756                         }
1757                 }
1758
1759                 if (!found)
1760                         unlink(path.buf);
1761         }
1762
1763 out:
1764         strbuf_release(&path);
1765 }
1766
1767 int write_commit_graph(const char *obj_dir,
1768                        struct string_list *pack_indexes,
1769                        struct string_list *commit_hex,
1770                        enum commit_graph_write_flags flags,
1771                        const struct split_commit_graph_opts *split_opts)
1772 {
1773         struct write_commit_graph_context *ctx;
1774         uint32_t i, count_distinct = 0;
1775         size_t len;
1776         int res = 0;
1777
1778         if (!commit_graph_compatible(the_repository))
1779                 return 0;
1780
1781         ctx = xcalloc(1, sizeof(struct write_commit_graph_context));
1782         ctx->r = the_repository;
1783
1784         /* normalize object dir with no trailing slash */
1785         ctx->obj_dir = xmallocz(strlen(obj_dir) + 1);
1786         normalize_path_copy(ctx->obj_dir, obj_dir);
1787         len = strlen(ctx->obj_dir);
1788         if (len && ctx->obj_dir[len - 1] == '/')
1789                 ctx->obj_dir[len - 1] = 0;
1790
1791         ctx->append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0;
1792         ctx->report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0;
1793         ctx->split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
1794         ctx->check_oids = flags & COMMIT_GRAPH_WRITE_CHECK_OIDS ? 1 : 0;
1795         ctx->split_opts = split_opts;
1796
1797         if (ctx->split) {
1798                 struct commit_graph *g;
1799                 prepare_commit_graph(ctx->r);
1800
1801                 g = ctx->r->objects->commit_graph;
1802
1803                 while (g) {
1804                         ctx->num_commit_graphs_before++;
1805                         g = g->base_graph;
1806                 }
1807
1808                 if (ctx->num_commit_graphs_before) {
1809                         ALLOC_ARRAY(ctx->commit_graph_filenames_before, ctx->num_commit_graphs_before);
1810                         i = ctx->num_commit_graphs_before;
1811                         g = ctx->r->objects->commit_graph;
1812
1813                         while (g) {
1814                                 ctx->commit_graph_filenames_before[--i] = xstrdup(g->filename);
1815                                 g = g->base_graph;
1816                         }
1817                 }
1818         }
1819
1820         ctx->approx_nr_objects = approximate_object_count();
1821         ctx->oids.alloc = ctx->approx_nr_objects / 32;
1822
1823         if (ctx->split && split_opts && ctx->oids.alloc > split_opts->max_commits)
1824                 ctx->oids.alloc = split_opts->max_commits;
1825
1826         if (ctx->append) {
1827                 prepare_commit_graph_one(ctx->r, ctx->obj_dir);
1828                 if (ctx->r->objects->commit_graph)
1829                         ctx->oids.alloc += ctx->r->objects->commit_graph->num_commits;
1830         }
1831
1832         if (ctx->oids.alloc < 1024)
1833                 ctx->oids.alloc = 1024;
1834         ALLOC_ARRAY(ctx->oids.list, ctx->oids.alloc);
1835
1836         if (ctx->append && ctx->r->objects->commit_graph) {
1837                 struct commit_graph *g = ctx->r->objects->commit_graph;
1838                 for (i = 0; i < g->num_commits; i++) {
1839                         const unsigned char *hash = g->chunk_oid_lookup + g->hash_len * i;
1840                         hashcpy(ctx->oids.list[ctx->oids.nr++].hash, hash);
1841                 }
1842         }
1843
1844         if (pack_indexes) {
1845                 if ((res = fill_oids_from_packs(ctx, pack_indexes)))
1846                         goto cleanup;
1847         }
1848
1849         if (commit_hex) {
1850                 if ((res = fill_oids_from_commit_hex(ctx, commit_hex)))
1851                         goto cleanup;
1852         }
1853
1854         if (!pack_indexes && !commit_hex)
1855                 fill_oids_from_all_packs(ctx);
1856
1857         close_reachable(ctx);
1858
1859         count_distinct = count_distinct_commits(ctx);
1860
1861         if (count_distinct >= GRAPH_EDGE_LAST_MASK) {
1862                 error(_("the commit graph format cannot write %d commits"), count_distinct);
1863                 res = -1;
1864                 goto cleanup;
1865         }
1866
1867         ctx->commits.alloc = count_distinct;
1868         ALLOC_ARRAY(ctx->commits.list, ctx->commits.alloc);
1869
1870         copy_oids_to_commits(ctx);
1871
1872         if (ctx->commits.nr >= GRAPH_EDGE_LAST_MASK) {
1873                 error(_("too many commits to write graph"));
1874                 res = -1;
1875                 goto cleanup;
1876         }
1877
1878         if (!ctx->commits.nr)
1879                 goto cleanup;
1880
1881         if (ctx->split) {
1882                 split_graph_merge_strategy(ctx);
1883
1884                 merge_commit_graphs(ctx);
1885         } else
1886                 ctx->num_commit_graphs_after = 1;
1887
1888         compute_generation_numbers(ctx);
1889
1890         res = write_commit_graph_file(ctx);
1891
1892         if (ctx->split)
1893                 mark_commit_graphs(ctx);
1894
1895         expire_commit_graphs(ctx);
1896
1897 cleanup:
1898         free(ctx->graph_name);
1899         free(ctx->commits.list);
1900         free(ctx->oids.list);
1901         free(ctx->obj_dir);
1902
1903         if (ctx->commit_graph_filenames_after) {
1904                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
1905                         free(ctx->commit_graph_filenames_after[i]);
1906                         free(ctx->commit_graph_hash_after[i]);
1907                 }
1908
1909                 for (i = 0; i < ctx->num_commit_graphs_before; i++)
1910                         free(ctx->commit_graph_filenames_before[i]);
1911
1912                 free(ctx->commit_graph_filenames_after);
1913                 free(ctx->commit_graph_filenames_before);
1914                 free(ctx->commit_graph_hash_after);
1915         }
1916
1917         free(ctx);
1918
1919         return res;
1920 }
1921
1922 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
1923 static int verify_commit_graph_error;
1924
1925 static void graph_report(const char *fmt, ...)
1926 {
1927         va_list ap;
1928
1929         verify_commit_graph_error = 1;
1930         va_start(ap, fmt);
1931         vfprintf(stderr, fmt, ap);
1932         fprintf(stderr, "\n");
1933         va_end(ap);
1934 }
1935
1936 #define GENERATION_ZERO_EXISTS 1
1937 #define GENERATION_NUMBER_EXISTS 2
1938
1939 int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
1940 {
1941         uint32_t i, cur_fanout_pos = 0;
1942         struct object_id prev_oid, cur_oid, checksum;
1943         int generation_zero = 0;
1944         struct hashfile *f;
1945         int devnull;
1946         struct progress *progress = NULL;
1947         int local_error = 0;
1948
1949         if (!g) {
1950                 graph_report("no commit-graph file loaded");
1951                 return 1;
1952         }
1953
1954         verify_commit_graph_error = verify_commit_graph_lite(g);
1955         if (verify_commit_graph_error)
1956                 return verify_commit_graph_error;
1957
1958         devnull = open("/dev/null", O_WRONLY);
1959         f = hashfd(devnull, NULL);
1960         hashwrite(f, g->data, g->data_len - g->hash_len);
1961         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
1962         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
1963                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
1964                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
1965         }
1966
1967         for (i = 0; i < g->num_commits; i++) {
1968                 struct commit *graph_commit;
1969
1970                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1971
1972                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
1973                         graph_report(_("commit-graph has incorrect OID order: %s then %s"),
1974                                      oid_to_hex(&prev_oid),
1975                                      oid_to_hex(&cur_oid));
1976
1977                 oidcpy(&prev_oid, &cur_oid);
1978
1979                 while (cur_oid.hash[0] > cur_fanout_pos) {
1980                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1981
1982                         if (i != fanout_value)
1983                                 graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
1984                                              cur_fanout_pos, fanout_value, i);
1985                         cur_fanout_pos++;
1986                 }
1987
1988                 graph_commit = lookup_commit(r, &cur_oid);
1989                 if (!parse_commit_in_graph_one(r, g, graph_commit))
1990                         graph_report(_("failed to parse commit %s from commit-graph"),
1991                                      oid_to_hex(&cur_oid));
1992         }
1993
1994         while (cur_fanout_pos < 256) {
1995                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1996
1997                 if (g->num_commits != fanout_value)
1998                         graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
1999                                      cur_fanout_pos, fanout_value, i);
2000
2001                 cur_fanout_pos++;
2002         }
2003
2004         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
2005                 return verify_commit_graph_error;
2006
2007         if (flags & COMMIT_GRAPH_WRITE_PROGRESS)
2008                 progress = start_progress(_("Verifying commits in commit graph"),
2009                                         g->num_commits);
2010
2011         for (i = 0; i < g->num_commits; i++) {
2012                 struct commit *graph_commit, *odb_commit;
2013                 struct commit_list *graph_parents, *odb_parents;
2014                 uint32_t max_generation = 0;
2015
2016                 display_progress(progress, i + 1);
2017                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
2018
2019                 graph_commit = lookup_commit(r, &cur_oid);
2020                 odb_commit = (struct commit *)create_object(r, &cur_oid, alloc_commit_node(r));
2021                 if (parse_commit_internal(odb_commit, 0, 0)) {
2022                         graph_report(_("failed to parse commit %s from object database for commit-graph"),
2023                                      oid_to_hex(&cur_oid));
2024                         continue;
2025                 }
2026
2027                 if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
2028                            get_commit_tree_oid(odb_commit)))
2029                         graph_report(_("root tree OID for commit %s in commit-graph is %s != %s"),
2030                                      oid_to_hex(&cur_oid),
2031                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
2032                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
2033
2034                 graph_parents = graph_commit->parents;
2035                 odb_parents = odb_commit->parents;
2036
2037                 while (graph_parents) {
2038                         if (odb_parents == NULL) {
2039                                 graph_report(_("commit-graph parent list for commit %s is too long"),
2040                                              oid_to_hex(&cur_oid));
2041                                 break;
2042                         }
2043
2044                         /* parse parent in case it is in a base graph */
2045                         parse_commit_in_graph_one(r, g, graph_parents->item);
2046
2047                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
2048                                 graph_report(_("commit-graph parent for %s is %s != %s"),
2049                                              oid_to_hex(&cur_oid),
2050                                              oid_to_hex(&graph_parents->item->object.oid),
2051                                              oid_to_hex(&odb_parents->item->object.oid));
2052
2053                         if (graph_parents->item->generation > max_generation)
2054                                 max_generation = graph_parents->item->generation;
2055
2056                         graph_parents = graph_parents->next;
2057                         odb_parents = odb_parents->next;
2058                 }
2059
2060                 if (odb_parents != NULL)
2061                         graph_report(_("commit-graph parent list for commit %s terminates early"),
2062                                      oid_to_hex(&cur_oid));
2063
2064                 if (!graph_commit->generation) {
2065                         if (generation_zero == GENERATION_NUMBER_EXISTS)
2066                                 graph_report(_("commit-graph has generation number zero for commit %s, but non-zero elsewhere"),
2067                                              oid_to_hex(&cur_oid));
2068                         generation_zero = GENERATION_ZERO_EXISTS;
2069                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
2070                         graph_report(_("commit-graph has non-zero generation number for commit %s, but zero elsewhere"),
2071                                      oid_to_hex(&cur_oid));
2072
2073                 if (generation_zero == GENERATION_ZERO_EXISTS)
2074                         continue;
2075
2076                 /*
2077                  * If one of our parents has generation GENERATION_NUMBER_MAX, then
2078                  * our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
2079                  * extra logic in the following condition.
2080                  */
2081                 if (max_generation == GENERATION_NUMBER_MAX)
2082                         max_generation--;
2083
2084                 if (graph_commit->generation != max_generation + 1)
2085                         graph_report(_("commit-graph generation for commit %s is %u != %u"),
2086                                      oid_to_hex(&cur_oid),
2087                                      graph_commit->generation,
2088                                      max_generation + 1);
2089
2090                 if (graph_commit->date != odb_commit->date)
2091                         graph_report(_("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime),
2092                                      oid_to_hex(&cur_oid),
2093                                      graph_commit->date,
2094                                      odb_commit->date);
2095         }
2096         stop_progress(&progress);
2097
2098         local_error = verify_commit_graph_error;
2099
2100         if (!(flags & COMMIT_GRAPH_VERIFY_SHALLOW) && g->base_graph)
2101                 local_error |= verify_commit_graph(r, g->base_graph, flags);
2102
2103         return local_error;
2104 }
2105
2106 void free_commit_graph(struct commit_graph *g)
2107 {
2108         if (!g)
2109                 return;
2110         if (g->graph_fd >= 0) {
2111                 munmap((void *)g->data, g->data_len);
2112                 g->data = NULL;
2113                 close(g->graph_fd);
2114         }
2115         free(g->filename);
2116         free(g);
2117 }
2118
2119 void disable_commit_graph(struct repository *r)
2120 {
2121         r->commit_graph_disabled = 1;
2122 }