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(struct object_directory *odb)
  48 {
  49         return xstrfmt("%s/info/commit-graph", odb->path);
  50 }
  51
  52 static char *get_split_graph_filename(struct object_directory *odb,
  53                                       const char *oid_hex)
  54 {
  55         return xstrfmt("%s/info/commit-graphs/graph-%s.graph", odb->path,
  56                        oid_hex);
  57 }
  58
  59 static char *get_chain_filename(struct object_directory *odb)
  60 {
  61         return xstrfmt("%s/info/commit-graphs/commit-graph-chain", odb->path);
  62 }
  63
  64 static uint8_t oid_version(void)
  65 {
  66         return 1;
  67 }
  68
  69 static struct commit_graph *alloc_commit_graph(void)
  70 {
  71         struct commit_graph *g = xcalloc(1, sizeof(*g));
  72         g->graph_fd = -1;
  73
  74         return g;
  75 }
  76
  77 extern int read_replace_refs;
  78
  79 static int commit_graph_compatible(struct repository *r)
  80 {
  81         if (!r->gitdir)
  82                 return 0;
  83
  84         if (read_replace_refs) {
  85                 prepare_replace_object(r);
  86                 if (hashmap_get_size(&r->objects->replace_map->map))
  87                         return 0;
  88         }
  89
  90         prepare_commit_graft(r);
  91         if (r->parsed_objects && r->parsed_objects->grafts_nr)
  92                 return 0;
  93         if (is_repository_shallow(r))
  94                 return 0;
  95
  96         return 1;
  97 }
  98
  99 int open_commit_graph(const char *graph_file, int *fd, struct stat *st)
 100 {
 101         *fd = git_open(graph_file);
 102         if (*fd < 0)
 103                 return 0;
 104         if (fstat(*fd, st)) {
 105                 close(*fd);
 106                 return 0;
 107         }
 108         return 1;
 109 }
 110
 111 struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st,
 112                                                  struct object_directory *odb)
 113 {
 114         void *graph_map;
 115         size_t graph_size;
 116         struct commit_graph *ret;
 117
 118         graph_size = xsize_t(st->st_size);
 119
 120         if (graph_size < GRAPH_MIN_SIZE) {
 121                 close(fd);
 122                 error(_("commit-graph file is too small"));
 123                 return NULL;
 124         }
 125         graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
 126         ret = parse_commit_graph(graph_map, fd, graph_size);
 127
 128         if (ret)
 129                 ret->odb = odb;
 130         else {
 131                 munmap(graph_map, graph_size);
 132                 close(fd);
 133         }
 134
 135         return ret;
 136 }
 137
 138 static int verify_commit_graph_lite(struct commit_graph *g)
 139 {
 140         /*
 141          * Basic validation shared between parse_commit_graph()
 142          * which'll be called every time the graph is used, and the
 143          * much more expensive verify_commit_graph() used by
 144          * "commit-graph verify".
 145          *
 146          * There should only be very basic checks here to ensure that
 147          * we don't e.g. segfault in fill_commit_in_graph(), but
 148          * because this is a very hot codepath nothing that e.g. loops
 149          * over g->num_commits, or runs a checksum on the commit-graph
 150          * itself.
 151          */
 152         if (!g->chunk_oid_fanout) {
 153                 error("commit-graph is missing the OID Fanout chunk");
 154                 return 1;
 155         }
 156         if (!g->chunk_oid_lookup) {
 157                 error("commit-graph is missing the OID Lookup chunk");
 158                 return 1;
 159         }
 160         if (!g->chunk_commit_data) {
 161                 error("commit-graph is missing the Commit Data chunk");
 162                 return 1;
 163         }
 164
 165         return 0;
 166 }
 167
 168 struct commit_graph *parse_commit_graph(void *graph_map, int fd,
 169                                         size_t graph_size)
 170 {
 171         const unsigned char *data, *chunk_lookup;
 172         uint32_t i;
 173         struct commit_graph *graph;
 174         uint64_t last_chunk_offset;
 175         uint32_t last_chunk_id;
 176         uint32_t graph_signature;
 177         unsigned char graph_version, hash_version;
 178
 179         if (!graph_map)
 180                 return NULL;
 181
 182         if (graph_size < GRAPH_MIN_SIZE)
 183                 return NULL;
 184
 185         data = (const unsigned char *)graph_map;
 186
 187         graph_signature = get_be32(data);
 188         if (graph_signature != GRAPH_SIGNATURE) {
 189                 error(_("commit-graph signature %X does not match signature %X"),
 190                       graph_signature, GRAPH_SIGNATURE);
 191                 return NULL;
 192         }
 193
 194         graph_version = *(unsigned char*)(data + 4);
 195         if (graph_version != GRAPH_VERSION) {
 196                 error(_("commit-graph version %X does not match version %X"),
 197                       graph_version, GRAPH_VERSION);
 198                 return NULL;
 199         }
 200
 201         hash_version = *(unsigned char*)(data + 5);
 202         if (hash_version != oid_version()) {
 203                 error(_("commit-graph hash version %X does not match version %X"),
 204                       hash_version, oid_version());
 205                 return NULL;
 206         }
 207
 208         graph = alloc_commit_graph();
 209
 210         graph->hash_len = the_hash_algo->rawsz;
 211         graph->num_chunks = *(unsigned char*)(data + 6);
 212         graph->graph_fd = fd;
 213         graph->data = graph_map;
 214         graph->data_len = graph_size;
 215
 216         last_chunk_id = 0;
 217         last_chunk_offset = 8;
 218         chunk_lookup = data + 8;
 219         for (i = 0; i < graph->num_chunks; i++) {
 220                 uint32_t chunk_id;
 221                 uint64_t chunk_offset;
 222                 int chunk_repeated = 0;
 223
 224                 if (data + graph_size - chunk_lookup <
 225                     GRAPH_CHUNKLOOKUP_WIDTH) {
 226                         error(_("commit-graph chunk lookup table entry missing; file may be incomplete"));
 227                         free(graph);
 228                         return NULL;
 229                 }
 230
 231                 chunk_id = get_be32(chunk_lookup + 0);
 232                 chunk_offset = get_be64(chunk_lookup + 4);
 233
 234                 chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
 235
 236                 if (chunk_offset > graph_size - the_hash_algo->rawsz) {
 237                         error(_("commit-graph improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
 238                               (uint32_t)chunk_offset);
 239                         free(graph);
 240                         return NULL;
 241                 }
 242
 243                 switch (chunk_id) {
 244                 case GRAPH_CHUNKID_OIDFANOUT:
 245                         if (graph->chunk_oid_fanout)
 246                                 chunk_repeated = 1;
 247                         else
 248                                 graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
 249                         break;
 250
 251                 case GRAPH_CHUNKID_OIDLOOKUP:
 252                         if (graph->chunk_oid_lookup)
 253                                 chunk_repeated = 1;
 254                         else
 255                                 graph->chunk_oid_lookup = data + chunk_offset;
 256                         break;
 257
 258                 case GRAPH_CHUNKID_DATA:
 259                         if (graph->chunk_commit_data)
 260                                 chunk_repeated = 1;
 261                         else
 262                                 graph->chunk_commit_data = data + chunk_offset;
 263                         break;
 264
 265                 case GRAPH_CHUNKID_EXTRAEDGES:
 266                         if (graph->chunk_extra_edges)
 267                                 chunk_repeated = 1;
 268                         else
 269                                 graph->chunk_extra_edges = data + chunk_offset;
 270                         break;
 271
 272                 case GRAPH_CHUNKID_BASE:
 273                         if (graph->chunk_base_graphs)
 274                                 chunk_repeated = 1;
 275                         else
 276                                 graph->chunk_base_graphs = data + chunk_offset;
 277                 }
 278
 279                 if (chunk_repeated) {
 280                         error(_("commit-graph chunk id %08x appears multiple times"), chunk_id);
 281                         free(graph);
 282                         return NULL;
 283                 }
 284
 285                 if (last_chunk_id == GRAPH_CHUNKID_OIDLOOKUP)
 286                 {
 287                         graph->num_commits = (chunk_offset - last_chunk_offset)
 288                                              / graph->hash_len;
 289                 }
 290
 291                 last_chunk_id = chunk_id;
 292                 last_chunk_offset = chunk_offset;
 293         }
 294
 295         hashcpy(graph->oid.hash, graph->data + graph->data_len - graph->hash_len);
 296
 297         if (verify_commit_graph_lite(graph)) {
 298                 free(graph);
 299                 return NULL;
 300         }
 301
 302         return graph;
 303 }
 304
 305 static struct commit_graph *load_commit_graph_one(const char *graph_file,
 306                                                   struct object_directory *odb)
 307 {
 308
 309         struct stat st;
 310         int fd;
 311         struct commit_graph *g;
 312         int open_ok = open_commit_graph(graph_file, &fd, &st);
 313
 314         if (!open_ok)
 315                 return NULL;
 316
 317         g = load_commit_graph_one_fd_st(fd, &st, odb);
 318
 319         if (g)
 320                 g->filename = xstrdup(graph_file);
 321
 322         return g;
 323 }
 324
 325 static struct commit_graph *load_commit_graph_v1(struct repository *r,
 326                                                  struct object_directory *odb)
 327 {
 328         char *graph_name = get_commit_graph_filename(odb);
 329         struct commit_graph *g = load_commit_graph_one(graph_name, odb);
 330         free(graph_name);
 331
 332         return g;
 333 }
 334
 335 static int add_graph_to_chain(struct commit_graph *g,
 336                               struct commit_graph *chain,
 337                               struct object_id *oids,
 338                               int n)
 339 {
 340         struct commit_graph *cur_g = chain;
 341
 342         if (n && !g->chunk_base_graphs) {
 343                 warning(_("commit-graph has no base graphs chunk"));
 344                 return 0;
 345         }
 346
 347         while (n) {
 348                 n--;
 349
 350                 if (!cur_g ||
 351                     !oideq(&oids[n], &cur_g->oid) ||
 352                     !hasheq(oids[n].hash, g->chunk_base_graphs + g->hash_len * n)) {
 353                         warning(_("commit-graph chain does not match"));
 354                         return 0;
 355                 }
 356
 357                 cur_g = cur_g->base_graph;
 358         }
 359
 360         g->base_graph = chain;
 361
 362         if (chain)
 363                 g->num_commits_in_base = chain->num_commits + chain->num_commits_in_base;
 364
 365         return 1;
 366 }
 367
 368 static struct commit_graph *load_commit_graph_chain(struct repository *r,
 369                                                     struct object_directory *odb)
 370 {
 371         struct commit_graph *graph_chain = NULL;
 372         struct strbuf line = STRBUF_INIT;
 373         struct stat st;
 374         struct object_id *oids;
 375         int i = 0, valid = 1, count;
 376         char *chain_name = get_chain_filename(odb);
 377         FILE *fp;
 378         int stat_res;
 379
 380         fp = fopen(chain_name, "r");
 381         stat_res = stat(chain_name, &st);
 382         free(chain_name);
 383
 384         if (!fp ||
 385             stat_res ||
 386             st.st_size <= the_hash_algo->hexsz)
 387                 return NULL;
 388
 389         count = st.st_size / (the_hash_algo->hexsz + 1);
 390         oids = xcalloc(count, sizeof(struct object_id));
 391
 392         prepare_alt_odb(r);
 393
 394         for (i = 0; i < count; i++) {
 395                 struct object_directory *odb;
 396
 397                 if (strbuf_getline_lf(&line, fp) == EOF)
 398                         break;
 399
 400                 if (get_oid_hex(line.buf, &oids[i])) {
 401                         warning(_("invalid commit-graph chain: line '%s' not a hash"),
 402                                 line.buf);
 403                         valid = 0;
 404                         break;
 405                 }
 406
 407                 valid = 0;
 408                 for (odb = r->objects->odb; odb; odb = odb->next) {
 409                         char *graph_name = get_split_graph_filename(odb, line.buf);
 410                         struct commit_graph *g = load_commit_graph_one(graph_name, odb);
 411
 412                         free(graph_name);
 413
 414                         if (g) {
 415                                 if (add_graph_to_chain(g, graph_chain, oids, i)) {
 416                                         graph_chain = g;
 417                                         valid = 1;
 418                                 }
 419
 420                                 break;
 421                         }
 422                 }
 423
 424                 if (!valid) {
 425                         warning(_("unable to find all commit-graph files"));
 426                         break;
 427                 }
 428         }
 429
 430         free(oids);
 431         fclose(fp);
 432         strbuf_release(&line);
 433
 434         return graph_chain;
 435 }
 436
 437 struct commit_graph *read_commit_graph_one(struct repository *r,
 438                                            struct object_directory *odb)
 439 {
 440         struct commit_graph *g = load_commit_graph_v1(r, odb);
 441
 442         if (!g)
 443                 g = load_commit_graph_chain(r, odb);
 444
 445         return g;
 446 }
 447
 448 static void prepare_commit_graph_one(struct repository *r,
 449                                      struct object_directory *odb)
 450 {
 451
 452         if (r->objects->commit_graph)
 453                 return;
 454
 455         r->objects->commit_graph = read_commit_graph_one(r, odb);
 456 }
 457
 458 /*
 459  * Return 1 if commit_graph is non-NULL, and 0 otherwise.
 460  *
 461  * On the first invocation, this function attempts to load the commit
 462  * graph if the_repository is configured to have one.
 463  */
 464 static int prepare_commit_graph(struct repository *r)
 465 {
 466         struct object_directory *odb;
 467
 468         /*
 469          * This must come before the "already attempted?" check below, because
 470          * we want to disable even an already-loaded graph file.
 471          */
 472         if (r->commit_graph_disabled)
 473                 return 0;
 474
 475         if (r->objects->commit_graph_attempted)
 476                 return !!r->objects->commit_graph;
 477         r->objects->commit_graph_attempted = 1;
 478
 479         if (git_env_bool(GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD, 0))
 480                 die("dying as requested by the '%s' variable on commit-graph load!",
 481                     GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD);
 482
 483         prepare_repo_settings(r);
 484
 485         if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
 486             r->settings.core_commit_graph != 1)
 487                 /*
 488                  * This repository is not configured to use commit graphs, so
 489                  * do not load one. (But report commit_graph_attempted anyway
 490                  * so that commit graph loading is not attempted again for this
 491                  * repository.)
 492                  */
 493                 return 0;
 494
 495         if (!commit_graph_compatible(r))
 496                 return 0;
 497
 498         prepare_alt_odb(r);
 499         for (odb = r->objects->odb;
 500              !r->objects->commit_graph && odb;
 501              odb = odb->next)
 502                 prepare_commit_graph_one(r, odb);
 503         return !!r->objects->commit_graph;
 504 }
 505
 506 int generation_numbers_enabled(struct repository *r)
 507 {
 508         uint32_t first_generation;
 509         struct commit_graph *g;
 510         if (!prepare_commit_graph(r))
 511                return 0;
 512
 513         g = r->objects->commit_graph;
 514
 515         if (!g->num_commits)
 516                 return 0;
 517
 518         first_generation = get_be32(g->chunk_commit_data +
 519                                     g->hash_len + 8) >> 2;
 520
 521         return !!first_generation;
 522 }
 523
 524 static void close_commit_graph_one(struct commit_graph *g)
 525 {
 526         if (!g)
 527                 return;
 528
 529         close_commit_graph_one(g->base_graph);
 530         free_commit_graph(g);
 531 }
 532
 533 void close_commit_graph(struct raw_object_store *o)
 534 {
 535         close_commit_graph_one(o->commit_graph);
 536         o->commit_graph = NULL;
 537 }
 538
 539 static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
 540 {
 541         return bsearch_hash(oid->hash, g->chunk_oid_fanout,
 542                             g->chunk_oid_lookup, g->hash_len, pos);
 543 }
 544
 545 static void load_oid_from_graph(struct commit_graph *g,
 546                                 uint32_t pos,
 547                                 struct object_id *oid)
 548 {
 549         uint32_t lex_index;
 550
 551         while (g && pos < g->num_commits_in_base)
 552                 g = g->base_graph;
 553
 554         if (!g)
 555                 BUG("NULL commit-graph");
 556
 557         if (pos >= g->num_commits + g->num_commits_in_base)
 558                 die(_("invalid commit position. commit-graph is likely corrupt"));
 559
 560         lex_index = pos - g->num_commits_in_base;
 561
 562         hashcpy(oid->hash, g->chunk_oid_lookup + g->hash_len * lex_index);
 563 }
 564
 565 static struct commit_list **insert_parent_or_die(struct repository *r,
 566                                                  struct commit_graph *g,
 567                                                  uint32_t pos,
 568                                                  struct commit_list **pptr)
 569 {
 570         struct commit *c;
 571         struct object_id oid;
 572
 573         if (pos >= g->num_commits + g->num_commits_in_base)
 574                 die("invalid parent position %"PRIu32, pos);
 575
 576         load_oid_from_graph(g, pos, &oid);
 577         c = lookup_commit(r, &oid);
 578         if (!c)
 579                 die(_("could not find commit %s"), oid_to_hex(&oid));
 580         c->graph_pos = pos;
 581         return &commit_list_insert(c, pptr)->next;
 582 }
 583
 584 static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
 585 {
 586         const unsigned char *commit_data;
 587         uint32_t lex_index;
 588
 589         while (pos < g->num_commits_in_base)
 590                 g = g->base_graph;
 591
 592         lex_index = pos - g->num_commits_in_base;
 593         commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * lex_index;
 594         item->graph_pos = pos;
 595         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 596 }
 597
 598 static inline void set_commit_tree(struct commit *c, struct tree *t)
 599 {
 600         c->maybe_tree = t;
 601 }
 602
 603 static int fill_commit_in_graph(struct repository *r,
 604                                 struct commit *item,
 605                                 struct commit_graph *g, uint32_t pos)
 606 {
 607         uint32_t edge_value;
 608         uint32_t *parent_data_ptr;
 609         uint64_t date_low, date_high;
 610         struct commit_list **pptr;
 611         const unsigned char *commit_data;
 612         uint32_t lex_index;
 613
 614         while (pos < g->num_commits_in_base)
 615                 g = g->base_graph;
 616
 617         if (pos >= g->num_commits + g->num_commits_in_base)
 618                 die(_("invalid commit position. commit-graph is likely corrupt"));
 619
 620         /*
 621          * Store the "full" position, but then use the
 622          * "local" position for the rest of the calculation.
 623          */
 624         item->graph_pos = pos;
 625         lex_index = pos - g->num_commits_in_base;
 626
 627         commit_data = g->chunk_commit_data + (g->hash_len + 16) * lex_index;
 628
 629         item->object.parsed = 1;
 630
 631         set_commit_tree(item, NULL);
 632
 633         date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
 634         date_low = get_be32(commit_data + g->hash_len + 12);
 635         item->date = (timestamp_t)((date_high << 32) | date_low);
 636
 637         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 638
 639         pptr = &item->parents;
 640
 641         edge_value = get_be32(commit_data + g->hash_len);
 642         if (edge_value == GRAPH_PARENT_NONE)
 643                 return 1;
 644         pptr = insert_parent_or_die(r, g, edge_value, pptr);
 645
 646         edge_value = get_be32(commit_data + g->hash_len + 4);
 647         if (edge_value == GRAPH_PARENT_NONE)
 648                 return 1;
 649         if (!(edge_value & GRAPH_EXTRA_EDGES_NEEDED)) {
 650                 pptr = insert_parent_or_die(r, g, edge_value, pptr);
 651                 return 1;
 652         }
 653
 654         parent_data_ptr = (uint32_t*)(g->chunk_extra_edges +
 655                           4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
 656         do {
 657                 edge_value = get_be32(parent_data_ptr);
 658                 pptr = insert_parent_or_die(r, g,
 659                                             edge_value & GRAPH_EDGE_LAST_MASK,
 660                                             pptr);
 661                 parent_data_ptr++;
 662         } while (!(edge_value & GRAPH_LAST_EDGE));
 663
 664         return 1;
 665 }
 666
 667 static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 668 {
 669         if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
 670                 *pos = item->graph_pos;
 671                 return 1;
 672         } else {
 673                 struct commit_graph *cur_g = g;
 674                 uint32_t lex_index;
 675
 676                 while (cur_g && !bsearch_graph(cur_g, &(item->object.oid), &lex_index))
 677                         cur_g = cur_g->base_graph;
 678
 679                 if (cur_g) {
 680                         *pos = lex_index + cur_g->num_commits_in_base;
 681                         return 1;
 682                 }
 683
 684                 return 0;
 685         }
 686 }
 687
 688 static int parse_commit_in_graph_one(struct repository *r,
 689                                      struct commit_graph *g,
 690                                      struct commit *item)
 691 {
 692         uint32_t pos;
 693
 694         if (item->object.parsed)
 695                 return 1;
 696
 697         if (find_commit_in_graph(item, g, &pos))
 698                 return fill_commit_in_graph(r, item, g, pos);
 699
 700         return 0;
 701 }
 702
 703 int parse_commit_in_graph(struct repository *r, struct commit *item)
 704 {
 705         if (!prepare_commit_graph(r))
 706                 return 0;
 707         return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
 708 }
 709
 710 void load_commit_graph_info(struct repository *r, struct commit *item)
 711 {
 712         uint32_t pos;
 713         if (!prepare_commit_graph(r))
 714                 return;
 715         if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
 716                 fill_commit_graph_info(item, r->objects->commit_graph, pos);
 717 }
 718
 719 static struct tree *load_tree_for_commit(struct repository *r,
 720                                          struct commit_graph *g,
 721                                          struct commit *c)
 722 {
 723         struct object_id oid;
 724         const unsigned char *commit_data;
 725
 726         while (c->graph_pos < g->num_commits_in_base)
 727                 g = g->base_graph;
 728
 729         commit_data = g->chunk_commit_data +
 730                         GRAPH_DATA_WIDTH * (c->graph_pos - g->num_commits_in_base);
 731
 732         hashcpy(oid.hash, commit_data);
 733         set_commit_tree(c, lookup_tree(r, &oid));
 734
 735         return c->maybe_tree;
 736 }
 737
 738 static struct tree *get_commit_tree_in_graph_one(struct repository *r,
 739                                                  struct commit_graph *g,
 740                                                  const struct commit *c)
 741 {
 742         if (c->maybe_tree)
 743                 return c->maybe_tree;
 744         if (c->graph_pos == COMMIT_NOT_FROM_GRAPH)
 745                 BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
 746
 747         return load_tree_for_commit(r, g, (struct commit *)c);
 748 }
 749
 750 struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
 751 {
 752         return get_commit_tree_in_graph_one(r, r->objects->commit_graph, c);
 753 }
 754
 755 struct packed_commit_list {
 756         struct commit **list;
 757         int nr;
 758         int alloc;
 759 };
 760
 761 struct packed_oid_list {
 762         struct object_id *list;
 763         int nr;
 764         int alloc;
 765 };
 766
 767 struct write_commit_graph_context {
 768         struct repository *r;
 769         struct object_directory *odb;
 770         char *graph_name;
 771         struct packed_oid_list oids;
 772         struct packed_commit_list commits;
 773         int num_extra_edges;
 774         unsigned long approx_nr_objects;
 775         struct progress *progress;
 776         int progress_done;
 777         uint64_t progress_cnt;
 778
 779         char *base_graph_name;
 780         int num_commit_graphs_before;
 781         int num_commit_graphs_after;
 782         char **commit_graph_filenames_before;
 783         char **commit_graph_filenames_after;
 784         char **commit_graph_hash_after;
 785         uint32_t new_num_commits_in_base;
 786         struct commit_graph *new_base_graph;
 787
 788         unsigned append:1,
 789                  report_progress:1,
 790                  split:1,
 791                  check_oids:1;
 792
 793         const struct split_commit_graph_opts *split_opts;
 794 };
 795
 796 static void write_graph_chunk_fanout(struct hashfile *f,
 797                                      struct write_commit_graph_context *ctx)
 798 {
 799         int i, count = 0;
 800         struct commit **list = ctx->commits.list;
 801
 802         /*
 803          * Write the first-level table (the list is sorted,
 804          * but we use a 256-entry lookup to be able to avoid
 805          * having to do eight extra binary search iterations).
 806          */
 807         for (i = 0; i < 256; i++) {
 808                 while (count < ctx->commits.nr) {
 809                         if ((*list)->object.oid.hash[0] != i)
 810                                 break;
 811                         display_progress(ctx->progress, ++ctx->progress_cnt);
 812                         count++;
 813                         list++;
 814                 }
 815
 816                 hashwrite_be32(f, count);
 817         }
 818 }
 819
 820 static void write_graph_chunk_oids(struct hashfile *f, int hash_len,
 821                                    struct write_commit_graph_context *ctx)
 822 {
 823         struct commit **list = ctx->commits.list;
 824         int count;
 825         for (count = 0; count < ctx->commits.nr; count++, list++) {
 826                 display_progress(ctx->progress, ++ctx->progress_cnt);
 827                 hashwrite(f, (*list)->object.oid.hash, (int)hash_len);
 828         }
 829 }
 830
 831 static const unsigned char *commit_to_sha1(size_t index, void *table)
 832 {
 833         struct commit **commits = table;
 834         return commits[index]->object.oid.hash;
 835 }
 836
 837 static void write_graph_chunk_data(struct hashfile *f, int hash_len,
 838                                    struct write_commit_graph_context *ctx)
 839 {
 840         struct commit **list = ctx->commits.list;
 841         struct commit **last = ctx->commits.list + ctx->commits.nr;
 842         uint32_t num_extra_edges = 0;
 843
 844         while (list < last) {
 845                 struct commit_list *parent;
 846                 struct object_id *tree;
 847                 int edge_value;
 848                 uint32_t packedDate[2];
 849                 display_progress(ctx->progress, ++ctx->progress_cnt);
 850
 851                 if (parse_commit_no_graph(*list))
 852                         die(_("unable to parse commit %s"),
 853                                 oid_to_hex(&(*list)->object.oid));
 854                 tree = get_commit_tree_oid(*list);
 855                 hashwrite(f, tree->hash, hash_len);
 856
 857                 parent = (*list)->parents;
 858
 859                 if (!parent)
 860                         edge_value = GRAPH_PARENT_NONE;
 861                 else {
 862                         edge_value = sha1_pos(parent->item->object.oid.hash,
 863                                               ctx->commits.list,
 864                                               ctx->commits.nr,
 865                                               commit_to_sha1);
 866
 867                         if (edge_value >= 0)
 868                                 edge_value += ctx->new_num_commits_in_base;
 869                         else if (ctx->new_base_graph) {
 870                                 uint32_t pos;
 871                                 if (find_commit_in_graph(parent->item,
 872                                                          ctx->new_base_graph,
 873                                                          &pos))
 874                                         edge_value = pos;
 875                         }
 876
 877                         if (edge_value < 0)
 878                                 BUG("missing parent %s for commit %s",
 879                                     oid_to_hex(&parent->item->object.oid),
 880                                     oid_to_hex(&(*list)->object.oid));
 881                 }
 882
 883                 hashwrite_be32(f, edge_value);
 884
 885                 if (parent)
 886                         parent = parent->next;
 887
 888                 if (!parent)
 889                         edge_value = GRAPH_PARENT_NONE;
 890                 else if (parent->next)
 891                         edge_value = GRAPH_EXTRA_EDGES_NEEDED | num_extra_edges;
 892                 else {
 893                         edge_value = sha1_pos(parent->item->object.oid.hash,
 894                                               ctx->commits.list,
 895                                               ctx->commits.nr,
 896                                               commit_to_sha1);
 897
 898                         if (edge_value >= 0)
 899                                 edge_value += ctx->new_num_commits_in_base;
 900                         else if (ctx->new_base_graph) {
 901                                 uint32_t pos;
 902                                 if (find_commit_in_graph(parent->item,
 903                                                          ctx->new_base_graph,
 904                                                          &pos))
 905                                         edge_value = pos;
 906                         }
 907
 908                         if (edge_value < 0)
 909                                 BUG("missing parent %s for commit %s",
 910                                     oid_to_hex(&parent->item->object.oid),
 911                                     oid_to_hex(&(*list)->object.oid));
 912                 }
 913
 914                 hashwrite_be32(f, edge_value);
 915
 916                 if (edge_value & GRAPH_EXTRA_EDGES_NEEDED) {
 917                         do {
 918                                 num_extra_edges++;
 919                                 parent = parent->next;
 920                         } while (parent);
 921                 }
 922
 923                 if (sizeof((*list)->date) > 4)
 924                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
 925                 else
 926                         packedDate[0] = 0;
 927
 928                 packedDate[0] |= htonl((*list)->generation << 2);
 929
 930                 packedDate[1] = htonl((*list)->date);
 931                 hashwrite(f, packedDate, 8);
 932
 933                 list++;
 934         }
 935 }
 936
 937 static void write_graph_chunk_extra_edges(struct hashfile *f,
 938                                           struct write_commit_graph_context *ctx)
 939 {
 940         struct commit **list = ctx->commits.list;
 941         struct commit **last = ctx->commits.list + ctx->commits.nr;
 942         struct commit_list *parent;
 943
 944         while (list < last) {
 945                 int num_parents = 0;
 946
 947                 display_progress(ctx->progress, ++ctx->progress_cnt);
 948
 949                 for (parent = (*list)->parents; num_parents < 3 && parent;
 950                      parent = parent->next)
 951                         num_parents++;
 952
 953                 if (num_parents <= 2) {
 954                         list++;
 955                         continue;
 956                 }
 957
 958                 /* Since num_parents > 2, this initializer is safe. */
 959                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
 960                         int edge_value = sha1_pos(parent->item->object.oid.hash,
 961                                                   ctx->commits.list,
 962                                                   ctx->commits.nr,
 963                                                   commit_to_sha1);
 964
 965                         if (edge_value >= 0)
 966                                 edge_value += ctx->new_num_commits_in_base;
 967                         else if (ctx->new_base_graph) {
 968                                 uint32_t pos;
 969                                 if (find_commit_in_graph(parent->item,
 970                                                          ctx->new_base_graph,
 971                                                          &pos))
 972                                         edge_value = pos;
 973                         }
 974
 975                         if (edge_value < 0)
 976                                 BUG("missing parent %s for commit %s",
 977                                     oid_to_hex(&parent->item->object.oid),
 978                                     oid_to_hex(&(*list)->object.oid));
 979                         else if (!parent->next)
 980                                 edge_value |= GRAPH_LAST_EDGE;
 981
 982                         hashwrite_be32(f, edge_value);
 983                 }
 984
 985                 list++;
 986         }
 987 }
 988
 989 static int oid_compare(const void *_a, const void *_b)
 990 {
 991         const struct object_id *a = (const struct object_id *)_a;
 992         const struct object_id *b = (const struct object_id *)_b;
 993         return oidcmp(a, b);
 994 }
 995
 996 static int add_packed_commits(const struct object_id *oid,
 997                               struct packed_git *pack,
 998                               uint32_t pos,
 999                               void *data)
1000 {
1001         struct write_commit_graph_context *ctx = (struct write_commit_graph_context*)data;
1002         enum object_type type;
1003         off_t offset = nth_packed_object_offset(pack, pos);
1004         struct object_info oi = OBJECT_INFO_INIT;
1005
1006         if (ctx->progress)
1007                 display_progress(ctx->progress, ++ctx->progress_done);
1008
1009         oi.typep = &type;
1010         if (packed_object_info(ctx->r, pack, offset, &oi) < 0)
1011                 die(_("unable to get type of object %s"), oid_to_hex(oid));
1012
1013         if (type != OBJ_COMMIT)
1014                 return 0;
1015
1016         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1017         oidcpy(&(ctx->oids.list[ctx->oids.nr]), oid);
1018         ctx->oids.nr++;
1019
1020         return 0;
1021 }
1022
1023 static void add_missing_parents(struct write_commit_graph_context *ctx, struct commit *commit)
1024 {
1025         struct commit_list *parent;
1026         for (parent = commit->parents; parent; parent = parent->next) {
1027                 if (!(parent->item->object.flags & REACHABLE)) {
1028                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1029                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(parent->item->object.oid));
1030                         ctx->oids.nr++;
1031                         parent->item->object.flags |= REACHABLE;
1032                 }
1033         }
1034 }
1035
1036 static void close_reachable(struct write_commit_graph_context *ctx)
1037 {
1038         int i;
1039         struct commit *commit;
1040         enum commit_graph_split_flags flags = ctx->split_opts ?
1041                 ctx->split_opts->flags : COMMIT_GRAPH_SPLIT_UNSPECIFIED;
1042
1043         if (ctx->report_progress)
1044                 ctx->progress = start_delayed_progress(
1045                                         _("Loading known commits in commit graph"),
1046                                         ctx->oids.nr);
1047         for (i = 0; i < ctx->oids.nr; i++) {
1048                 display_progress(ctx->progress, i + 1);
1049                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1050                 if (commit)
1051                         commit->object.flags |= REACHABLE;
1052         }
1053         stop_progress(&ctx->progress);
1054
1055         /*
1056          * As this loop runs, ctx->oids.nr may grow, but not more
1057          * than the number of missing commits in the reachable
1058          * closure.
1059          */
1060         if (ctx->report_progress)
1061                 ctx->progress = start_delayed_progress(
1062                                         _("Expanding reachable commits in commit graph"),
1063                                         0);
1064         for (i = 0; i < ctx->oids.nr; i++) {
1065                 display_progress(ctx->progress, i + 1);
1066                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1067
1068                 if (!commit)
1069                         continue;
1070                 if (ctx->split) {
1071                         if ((!parse_commit(commit) &&
1072                              commit->graph_pos == COMMIT_NOT_FROM_GRAPH) ||
1073                             flags == COMMIT_GRAPH_SPLIT_REPLACE)
1074                                 add_missing_parents(ctx, commit);
1075                 } else if (!parse_commit_no_graph(commit))
1076                         add_missing_parents(ctx, commit);
1077         }
1078         stop_progress(&ctx->progress);
1079
1080         if (ctx->report_progress)
1081                 ctx->progress = start_delayed_progress(
1082                                         _("Clearing commit marks in commit graph"),
1083                                         ctx->oids.nr);
1084         for (i = 0; i < ctx->oids.nr; i++) {
1085                 display_progress(ctx->progress, i + 1);
1086                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1087
1088                 if (commit)
1089                         commit->object.flags &= ~REACHABLE;
1090         }
1091         stop_progress(&ctx->progress);
1092 }
1093
1094 static void compute_generation_numbers(struct write_commit_graph_context *ctx)
1095 {
1096         int i;
1097         struct commit_list *list = NULL;
1098
1099         if (ctx->report_progress)
1100                 ctx->progress = start_delayed_progress(
1101                                         _("Computing commit graph generation numbers"),
1102                                         ctx->commits.nr);
1103         for (i = 0; i < ctx->commits.nr; i++) {
1104                 display_progress(ctx->progress, i + 1);
1105                 if (ctx->commits.list[i]->generation != GENERATION_NUMBER_INFINITY &&
1106                     ctx->commits.list[i]->generation != GENERATION_NUMBER_ZERO)
1107                         continue;
1108
1109                 commit_list_insert(ctx->commits.list[i], &list);
1110                 while (list) {
1111                         struct commit *current = list->item;
1112                         struct commit_list *parent;
1113                         int all_parents_computed = 1;
1114                         uint32_t max_generation = 0;
1115
1116                         for (parent = current->parents; parent; parent = parent->next) {
1117                                 if (parent->item->generation == GENERATION_NUMBER_INFINITY ||
1118                                     parent->item->generation == GENERATION_NUMBER_ZERO) {
1119                                         all_parents_computed = 0;
1120                                         commit_list_insert(parent->item, &list);
1121                                         break;
1122                                 } else if (parent->item->generation > max_generation) {
1123                                         max_generation = parent->item->generation;
1124                                 }
1125                         }
1126
1127                         if (all_parents_computed) {
1128                                 current->generation = max_generation + 1;
1129                                 pop_commit(&list);
1130
1131                                 if (current->generation > GENERATION_NUMBER_MAX)
1132                                         current->generation = GENERATION_NUMBER_MAX;
1133                         }
1134                 }
1135         }
1136         stop_progress(&ctx->progress);
1137 }
1138
1139 static int add_ref_to_set(const char *refname,
1140                           const struct object_id *oid,
1141                           int flags, void *cb_data)
1142 {
1143         struct oidset *commits = (struct oidset *)cb_data;
1144
1145         oidset_insert(commits, oid);
1146         return 0;
1147 }
1148
1149 int write_commit_graph_reachable(struct object_directory *odb,
1150                                  enum commit_graph_write_flags flags,
1151                                  const struct split_commit_graph_opts *split_opts)
1152 {
1153         struct oidset commits = OIDSET_INIT;
1154         int result;
1155
1156         for_each_ref(add_ref_to_set, &commits);
1157         result = write_commit_graph(odb, NULL, &commits,
1158                                     flags, split_opts);
1159
1160         oidset_clear(&commits);
1161         return result;
1162 }
1163
1164 static int fill_oids_from_packs(struct write_commit_graph_context *ctx,
1165                                 struct string_list *pack_indexes)
1166 {
1167         uint32_t i;
1168         struct strbuf progress_title = STRBUF_INIT;
1169         struct strbuf packname = STRBUF_INIT;
1170         int dirlen;
1171
1172         strbuf_addf(&packname, "%s/pack/", ctx->odb->path);
1173         dirlen = packname.len;
1174         if (ctx->report_progress) {
1175                 strbuf_addf(&progress_title,
1176                             Q_("Finding commits for commit graph in %d pack",
1177                                "Finding commits for commit graph in %d packs",
1178                                pack_indexes->nr),
1179                             pack_indexes->nr);
1180                 ctx->progress = start_delayed_progress(progress_title.buf, 0);
1181                 ctx->progress_done = 0;
1182         }
1183         for (i = 0; i < pack_indexes->nr; i++) {
1184                 struct packed_git *p;
1185                 strbuf_setlen(&packname, dirlen);
1186                 strbuf_addstr(&packname, pack_indexes->items[i].string);
1187                 p = add_packed_git(packname.buf, packname.len, 1);
1188                 if (!p) {
1189                         error(_("error adding pack %s"), packname.buf);
1190                         return -1;
1191                 }
1192                 if (open_pack_index(p)) {
1193                         error(_("error opening index for %s"), packname.buf);
1194                         return -1;
1195                 }
1196                 for_each_object_in_pack(p, add_packed_commits, ctx,
1197                                         FOR_EACH_OBJECT_PACK_ORDER);
1198                 close_pack(p);
1199                 free(p);
1200         }
1201
1202         stop_progress(&ctx->progress);
1203         strbuf_release(&progress_title);
1204         strbuf_release(&packname);
1205
1206         return 0;
1207 }
1208
1209 static int fill_oids_from_commits(struct write_commit_graph_context *ctx,
1210                                   struct oidset *commits)
1211 {
1212         uint32_t i = 0;
1213         struct strbuf progress_title = STRBUF_INIT;
1214         struct oidset_iter iter;
1215         struct object_id *oid;
1216
1217         if (!oidset_size(commits))
1218                 return 0;
1219
1220         if (ctx->report_progress) {
1221                 strbuf_addf(&progress_title,
1222                             Q_("Finding commits for commit graph from %d ref",
1223                                "Finding commits for commit graph from %d refs",
1224                                oidset_size(commits)),
1225                             oidset_size(commits));
1226                 ctx->progress = start_delayed_progress(
1227                                         progress_title.buf,
1228                                         oidset_size(commits));
1229         }
1230
1231         oidset_iter_init(commits, &iter);
1232         while ((oid = oidset_iter_next(&iter))) {
1233                 struct commit *result;
1234
1235                 display_progress(ctx->progress, ++i);
1236
1237                 result = lookup_commit_reference_gently(ctx->r, oid, 1);
1238                 if (result) {
1239                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1240                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(result->object.oid));
1241                         ctx->oids.nr++;
1242                 } else if (ctx->check_oids) {
1243                         error(_("invalid commit object id: %s"),
1244                               oid_to_hex(oid));
1245                         return -1;
1246                 }
1247         }
1248
1249         stop_progress(&ctx->progress);
1250         strbuf_release(&progress_title);
1251
1252         return 0;
1253 }
1254
1255 static void fill_oids_from_all_packs(struct write_commit_graph_context *ctx)
1256 {
1257         if (ctx->report_progress)
1258                 ctx->progress = start_delayed_progress(
1259                         _("Finding commits for commit graph among packed objects"),
1260                         ctx->approx_nr_objects);
1261         for_each_packed_object(add_packed_commits, ctx,
1262                                FOR_EACH_OBJECT_PACK_ORDER);
1263         if (ctx->progress_done < ctx->approx_nr_objects)
1264                 display_progress(ctx->progress, ctx->approx_nr_objects);
1265         stop_progress(&ctx->progress);
1266 }
1267
1268 static uint32_t count_distinct_commits(struct write_commit_graph_context *ctx)
1269 {
1270         uint32_t i, count_distinct = 1;
1271
1272         if (ctx->report_progress)
1273                 ctx->progress = start_delayed_progress(
1274                         _("Counting distinct commits in commit graph"),
1275                         ctx->oids.nr);
1276         display_progress(ctx->progress, 0); /* TODO: Measure QSORT() progress */
1277         QSORT(ctx->oids.list, ctx->oids.nr, oid_compare);
1278
1279         for (i = 1; i < ctx->oids.nr; i++) {
1280                 display_progress(ctx->progress, i + 1);
1281                 if (!oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i])) {
1282                         if (ctx->split) {
1283                                 struct commit *c = lookup_commit(ctx->r, &ctx->oids.list[i]);
1284
1285                                 if (!c || c->graph_pos != COMMIT_NOT_FROM_GRAPH)
1286                                         continue;
1287                         }
1288
1289                         count_distinct++;
1290                 }
1291         }
1292         stop_progress(&ctx->progress);
1293
1294         return count_distinct;
1295 }
1296
1297 static void copy_oids_to_commits(struct write_commit_graph_context *ctx)
1298 {
1299         uint32_t i;
1300         enum commit_graph_split_flags flags = ctx->split_opts ?
1301                 ctx->split_opts->flags : COMMIT_GRAPH_SPLIT_UNSPECIFIED;
1302
1303         ctx->num_extra_edges = 0;
1304         if (ctx->report_progress)
1305                 ctx->progress = start_delayed_progress(
1306                         _("Finding extra edges in commit graph"),
1307                         ctx->oids.nr);
1308         for (i = 0; i < ctx->oids.nr; i++) {
1309                 unsigned int num_parents;
1310
1311                 display_progress(ctx->progress, i + 1);
1312                 if (i > 0 && oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i]))
1313                         continue;
1314
1315                 ALLOC_GROW(ctx->commits.list, ctx->commits.nr + 1, ctx->commits.alloc);
1316                 ctx->commits.list[ctx->commits.nr] = lookup_commit(ctx->r, &ctx->oids.list[i]);
1317
1318                 if (ctx->split && flags != COMMIT_GRAPH_SPLIT_REPLACE &&
1319                     ctx->commits.list[ctx->commits.nr]->graph_pos != COMMIT_NOT_FROM_GRAPH)
1320                         continue;
1321
1322                 if (ctx->split && flags == COMMIT_GRAPH_SPLIT_REPLACE)
1323                         parse_commit(ctx->commits.list[ctx->commits.nr]);
1324                 else
1325                         parse_commit_no_graph(ctx->commits.list[ctx->commits.nr]);
1326
1327                 num_parents = commit_list_count(ctx->commits.list[ctx->commits.nr]->parents);
1328                 if (num_parents > 2)
1329                         ctx->num_extra_edges += num_parents - 1;
1330
1331                 ctx->commits.nr++;
1332         }
1333         stop_progress(&ctx->progress);
1334 }
1335
1336 static int write_graph_chunk_base_1(struct hashfile *f,
1337                                     struct commit_graph *g)
1338 {
1339         int num = 0;
1340
1341         if (!g)
1342                 return 0;
1343
1344         num = write_graph_chunk_base_1(f, g->base_graph);
1345         hashwrite(f, g->oid.hash, the_hash_algo->rawsz);
1346         return num + 1;
1347 }
1348
1349 static int write_graph_chunk_base(struct hashfile *f,
1350                                   struct write_commit_graph_context *ctx)
1351 {
1352         int num = write_graph_chunk_base_1(f, ctx->new_base_graph);
1353
1354         if (num != ctx->num_commit_graphs_after - 1) {
1355                 error(_("failed to write correct number of base graph ids"));
1356                 return -1;
1357         }
1358
1359         return 0;
1360 }
1361
1362 static int write_commit_graph_file(struct write_commit_graph_context *ctx)
1363 {
1364         uint32_t i;
1365         int fd;
1366         struct hashfile *f;
1367         struct lock_file lk = LOCK_INIT;
1368         uint32_t chunk_ids[6];
1369         uint64_t chunk_offsets[6];
1370         const unsigned hashsz = the_hash_algo->rawsz;
1371         struct strbuf progress_title = STRBUF_INIT;
1372         int num_chunks = 3;
1373         struct object_id file_hash;
1374
1375         if (ctx->split) {
1376                 struct strbuf tmp_file = STRBUF_INIT;
1377
1378                 strbuf_addf(&tmp_file,
1379                             "%s/info/commit-graphs/tmp_graph_XXXXXX",
1380                             ctx->odb->path);
1381                 ctx->graph_name = strbuf_detach(&tmp_file, NULL);
1382         } else {
1383                 ctx->graph_name = get_commit_graph_filename(ctx->odb);
1384         }
1385
1386         if (safe_create_leading_directories(ctx->graph_name)) {
1387                 UNLEAK(ctx->graph_name);
1388                 error(_("unable to create leading directories of %s"),
1389                         ctx->graph_name);
1390                 return -1;
1391         }
1392
1393         if (ctx->split) {
1394                 char *lock_name = get_chain_filename(ctx->odb);
1395
1396                 hold_lock_file_for_update(&lk, lock_name, LOCK_DIE_ON_ERROR);
1397
1398                 fd = git_mkstemp_mode(ctx->graph_name, 0444);
1399                 if (fd < 0) {
1400                         error(_("unable to create '%s'"), ctx->graph_name);
1401                         return -1;
1402                 }
1403
1404                 f = hashfd(fd, ctx->graph_name);
1405         } else {
1406                 hold_lock_file_for_update(&lk, ctx->graph_name, LOCK_DIE_ON_ERROR);
1407                 fd = lk.tempfile->fd;
1408                 f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
1409         }
1410
1411         chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
1412         chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
1413         chunk_ids[2] = GRAPH_CHUNKID_DATA;
1414         if (ctx->num_extra_edges) {
1415                 chunk_ids[num_chunks] = GRAPH_CHUNKID_EXTRAEDGES;
1416                 num_chunks++;
1417         }
1418         if (ctx->num_commit_graphs_after > 1) {
1419                 chunk_ids[num_chunks] = GRAPH_CHUNKID_BASE;
1420                 num_chunks++;
1421         }
1422
1423         chunk_ids[num_chunks] = 0;
1424
1425         chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
1426         chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
1427         chunk_offsets[2] = chunk_offsets[1] + hashsz * ctx->commits.nr;
1428         chunk_offsets[3] = chunk_offsets[2] + (hashsz + 16) * ctx->commits.nr;
1429
1430         num_chunks = 3;
1431         if (ctx->num_extra_edges) {
1432                 chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
1433                                                 4 * ctx->num_extra_edges;
1434                 num_chunks++;
1435         }
1436         if (ctx->num_commit_graphs_after > 1) {
1437                 chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
1438                                                 hashsz * (ctx->num_commit_graphs_after - 1);
1439                 num_chunks++;
1440         }
1441
1442         hashwrite_be32(f, GRAPH_SIGNATURE);
1443
1444         hashwrite_u8(f, GRAPH_VERSION);
1445         hashwrite_u8(f, oid_version());
1446         hashwrite_u8(f, num_chunks);
1447         hashwrite_u8(f, ctx->num_commit_graphs_after - 1);
1448
1449         for (i = 0; i <= num_chunks; i++) {
1450                 uint32_t chunk_write[3];
1451
1452                 chunk_write[0] = htonl(chunk_ids[i]);
1453                 chunk_write[1] = htonl(chunk_offsets[i] >> 32);
1454                 chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
1455                 hashwrite(f, chunk_write, 12);
1456         }
1457
1458         if (ctx->report_progress) {
1459                 strbuf_addf(&progress_title,
1460                             Q_("Writing out commit graph in %d pass",
1461                                "Writing out commit graph in %d passes",
1462                                num_chunks),
1463                             num_chunks);
1464                 ctx->progress = start_delayed_progress(
1465                         progress_title.buf,
1466                         num_chunks * ctx->commits.nr);
1467         }
1468         write_graph_chunk_fanout(f, ctx);
1469         write_graph_chunk_oids(f, hashsz, ctx);
1470         write_graph_chunk_data(f, hashsz, ctx);
1471         if (ctx->num_extra_edges)
1472                 write_graph_chunk_extra_edges(f, ctx);
1473         if (ctx->num_commit_graphs_after > 1 &&
1474             write_graph_chunk_base(f, ctx)) {
1475                 return -1;
1476         }
1477         stop_progress(&ctx->progress);
1478         strbuf_release(&progress_title);
1479
1480         if (ctx->split && ctx->base_graph_name && ctx->num_commit_graphs_after > 1) {
1481                 char *new_base_hash = xstrdup(oid_to_hex(&ctx->new_base_graph->oid));
1482                 char *new_base_name = get_split_graph_filename(ctx->new_base_graph->odb, new_base_hash);
1483
1484                 free(ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2]);
1485                 free(ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2]);
1486                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2] = new_base_name;
1487                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2] = new_base_hash;
1488         }
1489
1490         close_commit_graph(ctx->r->objects);
1491         finalize_hashfile(f, file_hash.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
1492
1493         if (ctx->split) {
1494                 FILE *chainf = fdopen_lock_file(&lk, "w");
1495                 char *final_graph_name;
1496                 int result;
1497
1498                 close(fd);
1499
1500                 if (!chainf) {
1501                         error(_("unable to open commit-graph chain file"));
1502                         return -1;
1503                 }
1504
1505                 if (ctx->base_graph_name) {
1506                         const char *dest;
1507                         int idx = ctx->num_commit_graphs_after - 1;
1508                         if (ctx->num_commit_graphs_after > 1)
1509                                 idx--;
1510
1511                         dest = ctx->commit_graph_filenames_after[idx];
1512
1513                         if (strcmp(ctx->base_graph_name, dest)) {
1514                                 result = rename(ctx->base_graph_name, dest);
1515
1516                                 if (result) {
1517                                         error(_("failed to rename base commit-graph file"));
1518                                         return -1;
1519                                 }
1520                         }
1521                 } else {
1522                         char *graph_name = get_commit_graph_filename(ctx->odb);
1523                         unlink(graph_name);
1524                 }
1525
1526                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(oid_to_hex(&file_hash));
1527                 final_graph_name = get_split_graph_filename(ctx->odb,
1528                                         ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
1529                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1] = final_graph_name;
1530
1531                 result = rename(ctx->graph_name, final_graph_name);
1532
1533                 for (i = 0; i < ctx->num_commit_graphs_after; i++)
1534                         fprintf(lk.tempfile->fp, "%s\n", ctx->commit_graph_hash_after[i]);
1535
1536                 if (result) {
1537                         error(_("failed to rename temporary commit-graph file"));
1538                         return -1;
1539                 }
1540         }
1541
1542         commit_lock_file(&lk);
1543
1544         return 0;
1545 }
1546
1547 static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
1548 {
1549         struct commit_graph *g;
1550         uint32_t num_commits;
1551         enum commit_graph_split_flags flags = COMMIT_GRAPH_SPLIT_UNSPECIFIED;
1552         uint32_t i;
1553
1554         int max_commits = 0;
1555         int size_mult = 2;
1556
1557         if (ctx->split_opts) {
1558                 max_commits = ctx->split_opts->max_commits;
1559
1560                 if (ctx->split_opts->size_multiple)
1561                         size_mult = ctx->split_opts->size_multiple;
1562
1563                 flags = ctx->split_opts->flags;
1564         }
1565
1566         g = ctx->r->objects->commit_graph;
1567         num_commits = ctx->commits.nr;
1568         if (flags == COMMIT_GRAPH_SPLIT_REPLACE)
1569                 ctx->num_commit_graphs_after = 1;
1570         else
1571                 ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1;
1572
1573         if (flags != COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED &&
1574             flags != COMMIT_GRAPH_SPLIT_REPLACE) {
1575                 while (g && (g->num_commits <= size_mult * num_commits ||
1576                             (max_commits && num_commits > max_commits))) {
1577                         if (g->odb != ctx->odb)
1578                                 break;
1579
1580                         num_commits += g->num_commits;
1581                         g = g->base_graph;
1582
1583                         ctx->num_commit_graphs_after--;
1584                 }
1585         }
1586
1587         if (flags != COMMIT_GRAPH_SPLIT_REPLACE)
1588                 ctx->new_base_graph = g;
1589         else if (ctx->num_commit_graphs_after != 1)
1590                 BUG("split_graph_merge_strategy: num_commit_graphs_after "
1591                     "should be 1 with --split=replace");
1592
1593         if (ctx->num_commit_graphs_after == 2) {
1594                 char *old_graph_name = get_commit_graph_filename(g->odb);
1595
1596                 if (!strcmp(g->filename, old_graph_name) &&
1597                     g->odb != ctx->odb) {
1598                         ctx->num_commit_graphs_after = 1;
1599                         ctx->new_base_graph = NULL;
1600                 }
1601
1602                 free(old_graph_name);
1603         }
1604
1605         ALLOC_ARRAY(ctx->commit_graph_filenames_after, ctx->num_commit_graphs_after);
1606         ALLOC_ARRAY(ctx->commit_graph_hash_after, ctx->num_commit_graphs_after);
1607
1608         for (i = 0; i < ctx->num_commit_graphs_after &&
1609                     i < ctx->num_commit_graphs_before; i++)
1610                 ctx->commit_graph_filenames_after[i] = xstrdup(ctx->commit_graph_filenames_before[i]);
1611
1612         i = ctx->num_commit_graphs_before - 1;
1613         g = ctx->r->objects->commit_graph;
1614
1615         while (g) {
1616                 if (i < ctx->num_commit_graphs_after)
1617                         ctx->commit_graph_hash_after[i] = xstrdup(oid_to_hex(&g->oid));
1618
1619                 i--;
1620                 g = g->base_graph;
1621         }
1622 }
1623
1624 static void merge_commit_graph(struct write_commit_graph_context *ctx,
1625                                struct commit_graph *g)
1626 {
1627         uint32_t i;
1628         uint32_t offset = g->num_commits_in_base;
1629
1630         ALLOC_GROW(ctx->commits.list, ctx->commits.nr + g->num_commits, ctx->commits.alloc);
1631
1632         for (i = 0; i < g->num_commits; i++) {
1633                 struct object_id oid;
1634                 struct commit *result;
1635
1636                 display_progress(ctx->progress, i + 1);
1637
1638                 load_oid_from_graph(g, i + offset, &oid);
1639
1640                 /* only add commits if they still exist in the repo */
1641                 result = lookup_commit_reference_gently(ctx->r, &oid, 1);
1642
1643                 if (result) {
1644                         ctx->commits.list[ctx->commits.nr] = result;
1645                         ctx->commits.nr++;
1646                 }
1647         }
1648 }
1649
1650 static int commit_compare(const void *_a, const void *_b)
1651 {
1652         const struct commit *a = *(const struct commit **)_a;
1653         const struct commit *b = *(const struct commit **)_b;
1654         return oidcmp(&a->object.oid, &b->object.oid);
1655 }
1656
1657 static void sort_and_scan_merged_commits(struct write_commit_graph_context *ctx)
1658 {
1659         uint32_t i;
1660
1661         if (ctx->report_progress)
1662                 ctx->progress = start_delayed_progress(
1663                                         _("Scanning merged commits"),
1664                                         ctx->commits.nr);
1665
1666         QSORT(ctx->commits.list, ctx->commits.nr, commit_compare);
1667
1668         ctx->num_extra_edges = 0;
1669         for (i = 0; i < ctx->commits.nr; i++) {
1670                 display_progress(ctx->progress, i);
1671
1672                 if (i && oideq(&ctx->commits.list[i - 1]->object.oid,
1673                           &ctx->commits.list[i]->object.oid)) {
1674                         die(_("unexpected duplicate commit id %s"),
1675                             oid_to_hex(&ctx->commits.list[i]->object.oid));
1676                 } else {
1677                         unsigned int num_parents;
1678
1679                         num_parents = commit_list_count(ctx->commits.list[i]->parents);
1680                         if (num_parents > 2)
1681                                 ctx->num_extra_edges += num_parents - 1;
1682                 }
1683         }
1684
1685         stop_progress(&ctx->progress);
1686 }
1687
1688 static void merge_commit_graphs(struct write_commit_graph_context *ctx)
1689 {
1690         struct commit_graph *g = ctx->r->objects->commit_graph;
1691         uint32_t current_graph_number = ctx->num_commit_graphs_before;
1692
1693         while (g && current_graph_number >= ctx->num_commit_graphs_after) {
1694                 current_graph_number--;
1695
1696                 if (ctx->report_progress)
1697                         ctx->progress = start_delayed_progress(_("Merging commit-graph"), 0);
1698
1699                 merge_commit_graph(ctx, g);
1700                 stop_progress(&ctx->progress);
1701
1702                 g = g->base_graph;
1703         }
1704
1705         if (g) {
1706                 ctx->new_base_graph = g;
1707                 ctx->new_num_commits_in_base = g->num_commits + g->num_commits_in_base;
1708         }
1709
1710         if (ctx->new_base_graph)
1711                 ctx->base_graph_name = xstrdup(ctx->new_base_graph->filename);
1712
1713         sort_and_scan_merged_commits(ctx);
1714 }
1715
1716 static void mark_commit_graphs(struct write_commit_graph_context *ctx)
1717 {
1718         uint32_t i;
1719         time_t now = time(NULL);
1720
1721         for (i = ctx->num_commit_graphs_after - 1; i < ctx->num_commit_graphs_before; i++) {
1722                 struct stat st;
1723                 struct utimbuf updated_time;
1724
1725                 stat(ctx->commit_graph_filenames_before[i], &st);
1726
1727                 updated_time.actime = st.st_atime;
1728                 updated_time.modtime = now;
1729                 utime(ctx->commit_graph_filenames_before[i], &updated_time);
1730         }
1731 }
1732
1733 static void expire_commit_graphs(struct write_commit_graph_context *ctx)
1734 {
1735         struct strbuf path = STRBUF_INIT;
1736         DIR *dir;
1737         struct dirent *de;
1738         size_t dirnamelen;
1739         timestamp_t expire_time = time(NULL);
1740
1741         if (ctx->split_opts && ctx->split_opts->expire_time)
1742                 expire_time = ctx->split_opts->expire_time;
1743         if (!ctx->split) {
1744                 char *chain_file_name = get_chain_filename(ctx->odb);
1745                 unlink(chain_file_name);
1746                 free(chain_file_name);
1747                 ctx->num_commit_graphs_after = 0;
1748         }
1749
1750         strbuf_addstr(&path, ctx->odb->path);
1751         strbuf_addstr(&path, "/info/commit-graphs");
1752         dir = opendir(path.buf);
1753
1754         if (!dir)
1755                 goto out;
1756
1757         strbuf_addch(&path, '/');
1758         dirnamelen = path.len;
1759         while ((de = readdir(dir)) != NULL) {
1760                 struct stat st;
1761                 uint32_t i, found = 0;
1762
1763                 strbuf_setlen(&path, dirnamelen);
1764                 strbuf_addstr(&path, de->d_name);
1765
1766                 stat(path.buf, &st);
1767
1768                 if (st.st_mtime > expire_time)
1769                         continue;
1770                 if (path.len < 6 || strcmp(path.buf + path.len - 6, ".graph"))
1771                         continue;
1772
1773                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
1774                         if (!strcmp(ctx->commit_graph_filenames_after[i],
1775                                     path.buf)) {
1776                                 found = 1;
1777                                 break;
1778                         }
1779                 }
1780
1781                 if (!found)
1782                         unlink(path.buf);
1783         }
1784
1785 out:
1786         strbuf_release(&path);
1787 }
1788
1789 int write_commit_graph(struct object_directory *odb,
1790                        struct string_list *pack_indexes,
1791                        struct oidset *commits,
1792                        enum commit_graph_write_flags flags,
1793                        const struct split_commit_graph_opts *split_opts)
1794 {
1795         struct write_commit_graph_context *ctx;
1796         uint32_t i, count_distinct = 0;
1797         int res = 0;
1798         int replace = 0;
1799
1800         if (!commit_graph_compatible(the_repository))
1801                 return 0;
1802
1803         ctx = xcalloc(1, sizeof(struct write_commit_graph_context));
1804         ctx->r = the_repository;
1805         ctx->odb = odb;
1806         ctx->append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0;
1807         ctx->report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0;
1808         ctx->split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
1809         ctx->check_oids = flags & COMMIT_GRAPH_WRITE_CHECK_OIDS ? 1 : 0;
1810         ctx->split_opts = split_opts;
1811
1812         if (ctx->split) {
1813                 struct commit_graph *g;
1814                 prepare_commit_graph(ctx->r);
1815
1816                 g = ctx->r->objects->commit_graph;
1817
1818                 while (g) {
1819                         ctx->num_commit_graphs_before++;
1820                         g = g->base_graph;
1821                 }
1822
1823                 if (ctx->num_commit_graphs_before) {
1824                         ALLOC_ARRAY(ctx->commit_graph_filenames_before, ctx->num_commit_graphs_before);
1825                         i = ctx->num_commit_graphs_before;
1826                         g = ctx->r->objects->commit_graph;
1827
1828                         while (g) {
1829                                 ctx->commit_graph_filenames_before[--i] = xstrdup(g->filename);
1830                                 g = g->base_graph;
1831                         }
1832                 }
1833
1834                 if (ctx->split_opts)
1835                         replace = ctx->split_opts->flags & COMMIT_GRAPH_SPLIT_REPLACE;
1836         }
1837
1838         ctx->approx_nr_objects = approximate_object_count();
1839         ctx->oids.alloc = ctx->approx_nr_objects / 32;
1840
1841         if (ctx->split && split_opts && ctx->oids.alloc > split_opts->max_commits)
1842                 ctx->oids.alloc = split_opts->max_commits;
1843
1844         if (ctx->append) {
1845                 prepare_commit_graph_one(ctx->r, ctx->odb);
1846                 if (ctx->r->objects->commit_graph)
1847                         ctx->oids.alloc += ctx->r->objects->commit_graph->num_commits;
1848         }
1849
1850         if (ctx->oids.alloc < 1024)
1851                 ctx->oids.alloc = 1024;
1852         ALLOC_ARRAY(ctx->oids.list, ctx->oids.alloc);
1853
1854         if (ctx->append && ctx->r->objects->commit_graph) {
1855                 struct commit_graph *g = ctx->r->objects->commit_graph;
1856                 for (i = 0; i < g->num_commits; i++) {
1857                         const unsigned char *hash = g->chunk_oid_lookup + g->hash_len * i;
1858                         hashcpy(ctx->oids.list[ctx->oids.nr++].hash, hash);
1859                 }
1860         }
1861
1862         if (pack_indexes) {
1863                 if ((res = fill_oids_from_packs(ctx, pack_indexes)))
1864                         goto cleanup;
1865         }
1866
1867         if (commits) {
1868                 if ((res = fill_oids_from_commits(ctx, commits)))
1869                         goto cleanup;
1870         }
1871
1872         if (!pack_indexes && !commits)
1873                 fill_oids_from_all_packs(ctx);
1874
1875         close_reachable(ctx);
1876
1877         count_distinct = count_distinct_commits(ctx);
1878
1879         if (count_distinct >= GRAPH_EDGE_LAST_MASK) {
1880                 error(_("the commit graph format cannot write %d commits"), count_distinct);
1881                 res = -1;
1882                 goto cleanup;
1883         }
1884
1885         ctx->commits.alloc = count_distinct;
1886         ALLOC_ARRAY(ctx->commits.list, ctx->commits.alloc);
1887
1888         copy_oids_to_commits(ctx);
1889
1890         if (ctx->commits.nr >= GRAPH_EDGE_LAST_MASK) {
1891                 error(_("too many commits to write graph"));
1892                 res = -1;
1893                 goto cleanup;
1894         }
1895
1896         if (!ctx->commits.nr && !replace)
1897                 goto cleanup;
1898
1899         if (ctx->split) {
1900                 split_graph_merge_strategy(ctx);
1901
1902                 if (!replace)
1903                         merge_commit_graphs(ctx);
1904         } else
1905                 ctx->num_commit_graphs_after = 1;
1906
1907         compute_generation_numbers(ctx);
1908
1909         res = write_commit_graph_file(ctx);
1910
1911         if (ctx->split)
1912                 mark_commit_graphs(ctx);
1913
1914         expire_commit_graphs(ctx);
1915
1916 cleanup:
1917         free(ctx->graph_name);
1918         free(ctx->commits.list);
1919         free(ctx->oids.list);
1920
1921         if (ctx->commit_graph_filenames_after) {
1922                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
1923                         free(ctx->commit_graph_filenames_after[i]);
1924                         free(ctx->commit_graph_hash_after[i]);
1925                 }
1926
1927                 for (i = 0; i < ctx->num_commit_graphs_before; i++)
1928                         free(ctx->commit_graph_filenames_before[i]);
1929
1930                 free(ctx->commit_graph_filenames_after);
1931                 free(ctx->commit_graph_filenames_before);
1932                 free(ctx->commit_graph_hash_after);
1933         }
1934
1935         free(ctx);
1936
1937         return res;
1938 }
1939
1940 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
1941 static int verify_commit_graph_error;
1942
1943 static void graph_report(const char *fmt, ...)
1944 {
1945         va_list ap;
1946
1947         verify_commit_graph_error = 1;
1948         va_start(ap, fmt);
1949         vfprintf(stderr, fmt, ap);
1950         fprintf(stderr, "\n");
1951         va_end(ap);
1952 }
1953
1954 #define GENERATION_ZERO_EXISTS 1
1955 #define GENERATION_NUMBER_EXISTS 2
1956
1957 int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
1958 {
1959         uint32_t i, cur_fanout_pos = 0;
1960         struct object_id prev_oid, cur_oid, checksum;
1961         int generation_zero = 0;
1962         struct hashfile *f;
1963         int devnull;
1964         struct progress *progress = NULL;
1965         int local_error = 0;
1966
1967         if (!g) {
1968                 graph_report("no commit-graph file loaded");
1969                 return 1;
1970         }
1971
1972         verify_commit_graph_error = verify_commit_graph_lite(g);
1973         if (verify_commit_graph_error)
1974                 return verify_commit_graph_error;
1975
1976         devnull = open("/dev/null", O_WRONLY);
1977         f = hashfd(devnull, NULL);
1978         hashwrite(f, g->data, g->data_len - g->hash_len);
1979         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
1980         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
1981                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
1982                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
1983         }
1984
1985         for (i = 0; i < g->num_commits; i++) {
1986                 struct commit *graph_commit;
1987
1988                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1989
1990                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
1991                         graph_report(_("commit-graph has incorrect OID order: %s then %s"),
1992                                      oid_to_hex(&prev_oid),
1993                                      oid_to_hex(&cur_oid));
1994
1995                 oidcpy(&prev_oid, &cur_oid);
1996
1997                 while (cur_oid.hash[0] > cur_fanout_pos) {
1998                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1999
2000                         if (i != fanout_value)
2001                                 graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
2002                                              cur_fanout_pos, fanout_value, i);
2003                         cur_fanout_pos++;
2004                 }
2005
2006                 graph_commit = lookup_commit(r, &cur_oid);
2007                 if (!parse_commit_in_graph_one(r, g, graph_commit))
2008                         graph_report(_("failed to parse commit %s from commit-graph"),
2009                                      oid_to_hex(&cur_oid));
2010         }
2011
2012         while (cur_fanout_pos < 256) {
2013                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
2014
2015                 if (g->num_commits != fanout_value)
2016                         graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
2017                                      cur_fanout_pos, fanout_value, i);
2018
2019                 cur_fanout_pos++;
2020         }
2021
2022         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
2023                 return verify_commit_graph_error;
2024
2025         if (flags & COMMIT_GRAPH_WRITE_PROGRESS)
2026                 progress = start_progress(_("Verifying commits in commit graph"),
2027                                         g->num_commits);
2028
2029         for (i = 0; i < g->num_commits; i++) {
2030                 struct commit *graph_commit, *odb_commit;
2031                 struct commit_list *graph_parents, *odb_parents;
2032                 uint32_t max_generation = 0;
2033
2034                 display_progress(progress, i + 1);
2035                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
2036
2037                 graph_commit = lookup_commit(r, &cur_oid);
2038                 odb_commit = (struct commit *)create_object(r, &cur_oid, alloc_commit_node(r));
2039                 if (parse_commit_internal(odb_commit, 0, 0)) {
2040                         graph_report(_("failed to parse commit %s from object database for commit-graph"),
2041                                      oid_to_hex(&cur_oid));
2042                         continue;
2043                 }
2044
2045                 if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
2046                            get_commit_tree_oid(odb_commit)))
2047                         graph_report(_("root tree OID for commit %s in commit-graph is %s != %s"),
2048                                      oid_to_hex(&cur_oid),
2049                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
2050                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
2051
2052                 graph_parents = graph_commit->parents;
2053                 odb_parents = odb_commit->parents;
2054
2055                 while (graph_parents) {
2056                         if (odb_parents == NULL) {
2057                                 graph_report(_("commit-graph parent list for commit %s is too long"),
2058                                              oid_to_hex(&cur_oid));
2059                                 break;
2060                         }
2061
2062                         /* parse parent in case it is in a base graph */
2063                         parse_commit_in_graph_one(r, g, graph_parents->item);
2064
2065                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
2066                                 graph_report(_("commit-graph parent for %s is %s != %s"),
2067                                              oid_to_hex(&cur_oid),
2068                                              oid_to_hex(&graph_parents->item->object.oid),
2069                                              oid_to_hex(&odb_parents->item->object.oid));
2070
2071                         if (graph_parents->item->generation > max_generation)
2072                                 max_generation = graph_parents->item->generation;
2073
2074                         graph_parents = graph_parents->next;
2075                         odb_parents = odb_parents->next;
2076                 }
2077
2078                 if (odb_parents != NULL)
2079                         graph_report(_("commit-graph parent list for commit %s terminates early"),
2080                                      oid_to_hex(&cur_oid));
2081
2082                 if (!graph_commit->generation) {
2083                         if (generation_zero == GENERATION_NUMBER_EXISTS)
2084                                 graph_report(_("commit-graph has generation number zero for commit %s, but non-zero elsewhere"),
2085                                              oid_to_hex(&cur_oid));
2086                         generation_zero = GENERATION_ZERO_EXISTS;
2087                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
2088                         graph_report(_("commit-graph has non-zero generation number for commit %s, but zero elsewhere"),
2089                                      oid_to_hex(&cur_oid));
2090
2091                 if (generation_zero == GENERATION_ZERO_EXISTS)
2092                         continue;
2093
2094                 /*
2095                  * If one of our parents has generation GENERATION_NUMBER_MAX, then
2096                  * our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
2097                  * extra logic in the following condition.
2098                  */
2099                 if (max_generation == GENERATION_NUMBER_MAX)
2100                         max_generation--;
2101
2102                 if (graph_commit->generation != max_generation + 1)
2103                         graph_report(_("commit-graph generation for commit %s is %u != %u"),
2104                                      oid_to_hex(&cur_oid),
2105                                      graph_commit->generation,
2106                                      max_generation + 1);
2107
2108                 if (graph_commit->date != odb_commit->date)
2109                         graph_report(_("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime),
2110                                      oid_to_hex(&cur_oid),
2111                                      graph_commit->date,
2112                                      odb_commit->date);
2113         }
2114         stop_progress(&progress);
2115
2116         local_error = verify_commit_graph_error;
2117
2118         if (!(flags & COMMIT_GRAPH_VERIFY_SHALLOW) && g->base_graph)
2119                 local_error |= verify_commit_graph(r, g->base_graph, flags);
2120
2121         return local_error;
2122 }
2123
2124 void free_commit_graph(struct commit_graph *g)
2125 {
2126         if (!g)
2127                 return;
2128         if (g->graph_fd >= 0) {
2129                 munmap((void *)g->data, g->data_len);
2130                 g->data = NULL;
2131                 close(g->graph_fd);
2132         }
2133         free(g->filename);
2134         free(g);
2135 }
2136
2137 void disable_commit_graph(struct repository *r)
2138 {
2139         r->commit_graph_disabled = 1;
2140 }