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

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "dir.h"
   4 #include "git-compat-util.h"
   5 #include "lockfile.h"
   6 #include "pack.h"
   7 #include "packfile.h"
   8 #include "commit.h"
   9 #include "object.h"
  10 #include "refs.h"
  11 #include "revision.h"
  12 #include "sha1-lookup.h"
  13 #include "commit-graph.h"
  14 #include "object-store.h"
  15 #include "alloc.h"
  16 #include "hashmap.h"
  17 #include "replace-object.h"
  18 #include "progress.h"
  19
  20 #define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */
  21 #define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
  22 #define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
  23 #define GRAPH_CHUNKID_DATA 0x43444154 /* "CDAT" */
  24 #define GRAPH_CHUNKID_EXTRAEDGES 0x45444745 /* "EDGE" */
  25 #define GRAPH_CHUNKID_BASE 0x42415345 /* "BASE" */
  26
  27 #define GRAPH_DATA_WIDTH (the_hash_algo->rawsz + 16)
  28
  29 #define GRAPH_VERSION_1 0x1
  30 #define GRAPH_VERSION GRAPH_VERSION_1
  31
  32 #define GRAPH_EXTRA_EDGES_NEEDED 0x80000000
  33 #define GRAPH_EDGE_LAST_MASK 0x7fffffff
  34 #define GRAPH_PARENT_NONE 0x70000000
  35
  36 #define GRAPH_LAST_EDGE 0x80000000
  37
  38 #define GRAPH_HEADER_SIZE 8
  39 #define GRAPH_FANOUT_SIZE (4 * 256)
  40 #define GRAPH_CHUNKLOOKUP_WIDTH 12
  41 #define GRAPH_MIN_SIZE (GRAPH_HEADER_SIZE + 4 * GRAPH_CHUNKLOOKUP_WIDTH \
  42                         + GRAPH_FANOUT_SIZE + the_hash_algo->rawsz)
  43
  44 char *get_commit_graph_filename(const char *obj_dir)
  45 {
  46         char *filename = xstrfmt("%s/info/commit-graph", obj_dir);
  47         char *normalized = xmalloc(strlen(filename) + 1);
  48         normalize_path_copy(normalized, filename);
  49         free(filename);
  50         return normalized;
  51 }
  52
  53 static char *get_split_graph_filename(const char *obj_dir,
  54                                       const char *oid_hex)
  55 {
  56         char *filename = xstrfmt("%s/info/commit-graphs/graph-%s.graph",
  57                                  obj_dir,
  58                                  oid_hex);
  59         char *normalized = xmalloc(strlen(filename) + 1);
  60         normalize_path_copy(normalized, filename);
  61         free(filename);
  62         return normalized;
  63 }
  64
  65 static char *get_chain_filename(const char *obj_dir)
  66 {
  67         return xstrfmt("%s/info/commit-graphs/commit-graph-chain", obj_dir);
  68 }
  69
  70 static uint8_t oid_version(void)
  71 {
  72         return 1;
  73 }
  74
  75 static struct commit_graph *alloc_commit_graph(void)
  76 {
  77         struct commit_graph *g = xcalloc(1, sizeof(*g));
  78         g->graph_fd = -1;
  79
  80         return g;
  81 }
  82
  83 extern int read_replace_refs;
  84
  85 static int commit_graph_compatible(struct repository *r)
  86 {
  87         if (!r->gitdir)
  88                 return 0;
  89
  90         if (read_replace_refs) {
  91                 prepare_replace_object(r);
  92                 if (hashmap_get_size(&r->objects->replace_map->map))
  93                         return 0;
  94         }
  95
  96         prepare_commit_graft(r);
  97         if (r->parsed_objects && r->parsed_objects->grafts_nr)
  98                 return 0;
  99         if (is_repository_shallow(r))
 100                 return 0;
 101
 102         return 1;
 103 }
 104
 105 int open_commit_graph(const char *graph_file, int *fd, struct stat *st)
 106 {
 107         *fd = git_open(graph_file);
 108         if (*fd < 0)
 109                 return 0;
 110         if (fstat(*fd, st)) {
 111                 close(*fd);
 112                 return 0;
 113         }
 114         return 1;
 115 }
 116
 117 struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st)
 118 {
 119         void *graph_map;
 120         size_t graph_size;
 121         struct commit_graph *ret;
 122
 123         graph_size = xsize_t(st->st_size);
 124
 125         if (graph_size < GRAPH_MIN_SIZE) {
 126                 close(fd);
 127                 error(_("commit-graph file is too small"));
 128                 return NULL;
 129         }
 130         graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
 131         ret = parse_commit_graph(graph_map, fd, graph_size);
 132
 133         if (!ret) {
 134                 munmap(graph_map, graph_size);
 135                 close(fd);
 136         }
 137
 138         return ret;
 139 }
 140
 141 static int verify_commit_graph_lite(struct commit_graph *g)
 142 {
 143         /*
 144          * Basic validation shared between parse_commit_graph()
 145          * which'll be called every time the graph is used, and the
 146          * much more expensive verify_commit_graph() used by
 147          * "commit-graph verify".
 148          *
 149          * There should only be very basic checks here to ensure that
 150          * we don't e.g. segfault in fill_commit_in_graph(), but
 151          * because this is a very hot codepath nothing that e.g. loops
 152          * over g->num_commits, or runs a checksum on the commit-graph
 153          * itself.
 154          */
 155         if (!g->chunk_oid_fanout) {
 156                 error("commit-graph is missing the OID Fanout chunk");
 157                 return 1;
 158         }
 159         if (!g->chunk_oid_lookup) {
 160                 error("commit-graph is missing the OID Lookup chunk");
 161                 return 1;
 162         }
 163         if (!g->chunk_commit_data) {
 164                 error("commit-graph is missing the Commit Data chunk");
 165                 return 1;
 166         }
 167
 168         return 0;
 169 }
 170
 171 struct commit_graph *parse_commit_graph(void *graph_map, int fd,
 172                                         size_t graph_size)
 173 {
 174         const unsigned char *data, *chunk_lookup;
 175         uint32_t i;
 176         struct commit_graph *graph;
 177         uint64_t last_chunk_offset;
 178         uint32_t last_chunk_id;
 179         uint32_t graph_signature;
 180         unsigned char graph_version, hash_version;
 181
 182         if (!graph_map)
 183                 return NULL;
 184
 185         if (graph_size < GRAPH_MIN_SIZE)
 186                 return NULL;
 187
 188         data = (const unsigned char *)graph_map;
 189
 190         graph_signature = get_be32(data);
 191         if (graph_signature != GRAPH_SIGNATURE) {
 192                 error(_("commit-graph signature %X does not match signature %X"),
 193                       graph_signature, GRAPH_SIGNATURE);
 194                 return NULL;
 195         }
 196
 197         graph_version = *(unsigned char*)(data + 4);
 198         if (graph_version != GRAPH_VERSION) {
 199                 error(_("commit-graph version %X does not match version %X"),
 200                       graph_version, GRAPH_VERSION);
 201                 return NULL;
 202         }
 203
 204         hash_version = *(unsigned char*)(data + 5);
 205         if (hash_version != oid_version()) {
 206                 error(_("commit-graph hash version %X does not match version %X"),
 207                       hash_version, oid_version());
 208                 return NULL;
 209         }
 210
 211         graph = alloc_commit_graph();
 212
 213         graph->hash_len = the_hash_algo->rawsz;
 214         graph->num_chunks = *(unsigned char*)(data + 6);
 215         graph->graph_fd = fd;
 216         graph->data = graph_map;
 217         graph->data_len = graph_size;
 218
 219         last_chunk_id = 0;
 220         last_chunk_offset = 8;
 221         chunk_lookup = data + 8;
 222         for (i = 0; i < graph->num_chunks; i++) {
 223                 uint32_t chunk_id;
 224                 uint64_t chunk_offset;
 225                 int chunk_repeated = 0;
 226
 227                 if (data + graph_size - chunk_lookup <
 228                     GRAPH_CHUNKLOOKUP_WIDTH) {
 229                         error(_("commit-graph chunk lookup table entry missing; file may be incomplete"));
 230                         free(graph);
 231                         return NULL;
 232                 }
 233
 234                 chunk_id = get_be32(chunk_lookup + 0);
 235                 chunk_offset = get_be64(chunk_lookup + 4);
 236
 237                 chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
 238
 239                 if (chunk_offset > graph_size - the_hash_algo->rawsz) {
 240                         error(_("commit-graph improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
 241                               (uint32_t)chunk_offset);
 242                         free(graph);
 243                         return NULL;
 244                 }
 245
 246                 switch (chunk_id) {
 247                 case GRAPH_CHUNKID_OIDFANOUT:
 248                         if (graph->chunk_oid_fanout)
 249                                 chunk_repeated = 1;
 250                         else
 251                                 graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
 252                         break;
 253
 254                 case GRAPH_CHUNKID_OIDLOOKUP:
 255                         if (graph->chunk_oid_lookup)
 256                                 chunk_repeated = 1;
 257                         else
 258                                 graph->chunk_oid_lookup = data + chunk_offset;
 259                         break;
 260
 261                 case GRAPH_CHUNKID_DATA:
 262                         if (graph->chunk_commit_data)
 263                                 chunk_repeated = 1;
 264                         else
 265                                 graph->chunk_commit_data = data + chunk_offset;
 266                         break;
 267
 268                 case GRAPH_CHUNKID_EXTRAEDGES:
 269                         if (graph->chunk_extra_edges)
 270                                 chunk_repeated = 1;
 271                         else
 272                                 graph->chunk_extra_edges = data + chunk_offset;
 273                         break;
 274
 275                 case GRAPH_CHUNKID_BASE:
 276                         if (graph->chunk_base_graphs)
 277                                 chunk_repeated = 1;
 278                         else
 279                                 graph->chunk_base_graphs = data + chunk_offset;
 280                 }
 281
 282                 if (chunk_repeated) {
 283                         error(_("commit-graph chunk id %08x appears multiple times"), chunk_id);
 284                         free(graph);
 285                         return NULL;
 286                 }
 287
 288                 if (last_chunk_id == GRAPH_CHUNKID_OIDLOOKUP)
 289                 {
 290                         graph->num_commits = (chunk_offset - last_chunk_offset)
 291                                              / graph->hash_len;
 292                 }
 293
 294                 last_chunk_id = chunk_id;
 295                 last_chunk_offset = chunk_offset;
 296         }
 297
 298         hashcpy(graph->oid.hash, graph->data + graph->data_len - graph->hash_len);
 299
 300         if (verify_commit_graph_lite(graph)) {
 301                 free(graph);
 302                 return NULL;
 303         }
 304
 305         return graph;
 306 }
 307
 308 static struct commit_graph *load_commit_graph_one(const char *graph_file)
 309 {
 310
 311         struct stat st;
 312         int fd;
 313         struct commit_graph *g;
 314         int open_ok = open_commit_graph(graph_file, &fd, &st);
 315
 316         if (!open_ok)
 317                 return NULL;
 318
 319         g = load_commit_graph_one_fd_st(fd, &st);
 320
 321         if (g)
 322                 g->filename = xstrdup(graph_file);
 323
 324         return g;
 325 }
 326
 327 static struct commit_graph *load_commit_graph_v1(struct repository *r, const char *obj_dir)
 328 {
 329         char *graph_name = get_commit_graph_filename(obj_dir);
 330         struct commit_graph *g = load_commit_graph_one(graph_name);
 331         free(graph_name);
 332
 333         if (g)
 334                 g->obj_dir = obj_dir;
 335
 336         return g;
 337 }
 338
 339 static int add_graph_to_chain(struct commit_graph *g,
 340                               struct commit_graph *chain,
 341                               struct object_id *oids,
 342                               int n)
 343 {
 344         struct commit_graph *cur_g = chain;
 345
 346         if (n && !g->chunk_base_graphs) {
 347                 warning(_("commit-graph has no base graphs chunk"));
 348                 return 0;
 349         }
 350
 351         while (n) {
 352                 n--;
 353
 354                 if (!cur_g ||
 355                     !oideq(&oids[n], &cur_g->oid) ||
 356                     !hasheq(oids[n].hash, g->chunk_base_graphs + g->hash_len * n)) {
 357                         warning(_("commit-graph chain does not match"));
 358                         return 0;
 359                 }
 360
 361                 cur_g = cur_g->base_graph;
 362         }
 363
 364         g->base_graph = chain;
 365
 366         if (chain)
 367                 g->num_commits_in_base = chain->num_commits + chain->num_commits_in_base;
 368
 369         return 1;
 370 }
 371
 372 static struct commit_graph *load_commit_graph_chain(struct repository *r, const char *obj_dir)
 373 {
 374         struct commit_graph *graph_chain = NULL;
 375         struct strbuf line = STRBUF_INIT;
 376         struct stat st;
 377         struct object_id *oids;
 378         int i = 0, valid = 1, count;
 379         char *chain_name = get_chain_filename(obj_dir);
 380         FILE *fp;
 381         int stat_res;
 382
 383         fp = fopen(chain_name, "r");
 384         stat_res = stat(chain_name, &st);
 385         free(chain_name);
 386
 387         if (!fp ||
 388             stat_res ||
 389             st.st_size <= the_hash_algo->hexsz)
 390                 return NULL;
 391
 392         count = st.st_size / (the_hash_algo->hexsz + 1);
 393         oids = xcalloc(count, sizeof(struct object_id));
 394
 395         prepare_alt_odb(r);
 396
 397         for (i = 0; i < count; i++) {
 398                 struct object_directory *odb;
 399
 400                 if (strbuf_getline_lf(&line, fp) == EOF)
 401                         break;
 402
 403                 if (get_oid_hex(line.buf, &oids[i])) {
 404                         warning(_("invalid commit-graph chain: line '%s' not a hash"),
 405                                 line.buf);
 406                         valid = 0;
 407                         break;
 408                 }
 409
 410                 valid = 0;
 411                 for (odb = r->objects->odb; odb; odb = odb->next) {
 412                         char *graph_name = get_split_graph_filename(odb->path, line.buf);
 413                         struct commit_graph *g = load_commit_graph_one(graph_name);
 414
 415                         free(graph_name);
 416
 417                         if (g) {
 418                                 g->obj_dir = odb->path;
 419
 420                                 if (add_graph_to_chain(g, graph_chain, oids, i)) {
 421                                         graph_chain = g;
 422                                         valid = 1;
 423                                 }
 424
 425                                 break;
 426                         }
 427                 }
 428
 429                 if (!valid) {
 430                         warning(_("unable to find all commit-graph files"));
 431                         break;
 432                 }
 433         }
 434
 435         free(oids);
 436         fclose(fp);
 437
 438         return graph_chain;
 439 }
 440
 441 struct commit_graph *read_commit_graph_one(struct repository *r, const char *obj_dir)
 442 {
 443         struct commit_graph *g = load_commit_graph_v1(r, obj_dir);
 444
 445         if (!g)
 446                 g = load_commit_graph_chain(r, obj_dir);
 447
 448         return g;
 449 }
 450
 451 static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
 452 {
 453
 454         if (r->objects->commit_graph)
 455                 return;
 456
 457         r->objects->commit_graph = read_commit_graph_one(r, obj_dir);
 458 }
 459
 460 /*
 461  * Return 1 if commit_graph is non-NULL, and 0 otherwise.
 462  *
 463  * On the first invocation, this function attemps to load the commit
 464  * graph if the_repository is configured to have one.
 465  */
 466 static int prepare_commit_graph(struct repository *r)
 467 {
 468         struct object_directory *odb;
 469         int config_value;
 470
 471         if (git_env_bool(GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD, 0))
 472                 die("dying as requested by the '%s' variable on commit-graph load!",
 473                     GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD);
 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, 0) &&
 480             (repo_config_get_bool(r, "core.commitgraph", &config_value) ||
 481             !config_value))
 482                 /*
 483                  * This repository is not configured to use commit graphs, so
 484                  * do not load one. (But report commit_graph_attempted anyway
 485                  * so that commit graph loading is not attempted again for this
 486                  * repository.)
 487                  */
 488                 return 0;
 489
 490         if (!commit_graph_compatible(r))
 491                 return 0;
 492
 493         prepare_alt_odb(r);
 494         for (odb = r->objects->odb;
 495              !r->objects->commit_graph && odb;
 496              odb = odb->next)
 497                 prepare_commit_graph_one(r, odb->path);
 498         return !!r->objects->commit_graph;
 499 }
 500
 501 int generation_numbers_enabled(struct repository *r)
 502 {
 503         uint32_t first_generation;
 504         struct commit_graph *g;
 505         if (!prepare_commit_graph(r))
 506                return 0;
 507
 508         g = r->objects->commit_graph;
 509
 510         if (!g->num_commits)
 511                 return 0;
 512
 513         first_generation = get_be32(g->chunk_commit_data +
 514                                     g->hash_len + 8) >> 2;
 515
 516         return !!first_generation;
 517 }
 518
 519 static void close_commit_graph_one(struct commit_graph *g)
 520 {
 521         if (!g)
 522                 return;
 523
 524         close_commit_graph_one(g->base_graph);
 525         free_commit_graph(g);
 526 }
 527
 528 void close_commit_graph(struct raw_object_store *o)
 529 {
 530         close_commit_graph_one(o->commit_graph);
 531         o->commit_graph = NULL;
 532 }
 533
 534 static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
 535 {
 536         return bsearch_hash(oid->hash, g->chunk_oid_fanout,
 537                             g->chunk_oid_lookup, g->hash_len, pos);
 538 }
 539
 540 static void load_oid_from_graph(struct commit_graph *g,
 541                                 uint32_t pos,
 542                                 struct object_id *oid)
 543 {
 544         uint32_t lex_index;
 545
 546         while (g && pos < g->num_commits_in_base)
 547                 g = g->base_graph;
 548
 549         if (!g)
 550                 BUG("NULL commit-graph");
 551
 552         if (pos >= g->num_commits + g->num_commits_in_base)
 553                 die(_("invalid commit position. commit-graph is likely corrupt"));
 554
 555         lex_index = pos - g->num_commits_in_base;
 556
 557         hashcpy(oid->hash, g->chunk_oid_lookup + g->hash_len * lex_index);
 558 }
 559
 560 static struct commit_list **insert_parent_or_die(struct repository *r,
 561                                                  struct commit_graph *g,
 562                                                  uint32_t pos,
 563                                                  struct commit_list **pptr)
 564 {
 565         struct commit *c;
 566         struct object_id oid;
 567
 568         if (pos >= g->num_commits + g->num_commits_in_base)
 569                 die("invalid parent position %"PRIu32, pos);
 570
 571         load_oid_from_graph(g, pos, &oid);
 572         c = lookup_commit(r, &oid);
 573         if (!c)
 574                 die(_("could not find commit %s"), oid_to_hex(&oid));
 575         c->graph_pos = pos;
 576         return &commit_list_insert(c, pptr)->next;
 577 }
 578
 579 static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
 580 {
 581         const unsigned char *commit_data;
 582         uint32_t lex_index;
 583
 584         while (pos < g->num_commits_in_base)
 585                 g = g->base_graph;
 586
 587         lex_index = pos - g->num_commits_in_base;
 588         commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * lex_index;
 589         item->graph_pos = pos;
 590         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 591 }
 592
 593 static inline void set_commit_tree(struct commit *c, struct tree *t)
 594 {
 595         c->maybe_tree = t;
 596 }
 597
 598 static int fill_commit_in_graph(struct repository *r,
 599                                 struct commit *item,
 600                                 struct commit_graph *g, uint32_t pos)
 601 {
 602         uint32_t edge_value;
 603         uint32_t *parent_data_ptr;
 604         uint64_t date_low, date_high;
 605         struct commit_list **pptr;
 606         const unsigned char *commit_data;
 607         uint32_t lex_index;
 608
 609         while (pos < g->num_commits_in_base)
 610                 g = g->base_graph;
 611
 612         if (pos >= g->num_commits + g->num_commits_in_base)
 613                 die(_("invalid commit position. commit-graph is likely corrupt"));
 614
 615         /*
 616          * Store the "full" position, but then use the
 617          * "local" position for the rest of the calculation.
 618          */
 619         item->graph_pos = pos;
 620         lex_index = pos - g->num_commits_in_base;
 621
 622         commit_data = g->chunk_commit_data + (g->hash_len + 16) * lex_index;
 623
 624         item->object.parsed = 1;
 625
 626         set_commit_tree(item, NULL);
 627
 628         date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
 629         date_low = get_be32(commit_data + g->hash_len + 12);
 630         item->date = (timestamp_t)((date_high << 32) | date_low);
 631
 632         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 633
 634         pptr = &item->parents;
 635
 636         edge_value = get_be32(commit_data + g->hash_len);
 637         if (edge_value == GRAPH_PARENT_NONE)
 638                 return 1;
 639         pptr = insert_parent_or_die(r, g, edge_value, pptr);
 640
 641         edge_value = get_be32(commit_data + g->hash_len + 4);
 642         if (edge_value == GRAPH_PARENT_NONE)
 643                 return 1;
 644         if (!(edge_value & GRAPH_EXTRA_EDGES_NEEDED)) {
 645                 pptr = insert_parent_or_die(r, g, edge_value, pptr);
 646                 return 1;
 647         }
 648
 649         parent_data_ptr = (uint32_t*)(g->chunk_extra_edges +
 650                           4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
 651         do {
 652                 edge_value = get_be32(parent_data_ptr);
 653                 pptr = insert_parent_or_die(r, g,
 654                                             edge_value & GRAPH_EDGE_LAST_MASK,
 655                                             pptr);
 656                 parent_data_ptr++;
 657         } while (!(edge_value & GRAPH_LAST_EDGE));
 658
 659         return 1;
 660 }
 661
 662 static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 663 {
 664         if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
 665                 *pos = item->graph_pos;
 666                 return 1;
 667         } else {
 668                 struct commit_graph *cur_g = g;
 669                 uint32_t lex_index;
 670
 671                 while (cur_g && !bsearch_graph(cur_g, &(item->object.oid), &lex_index))
 672                         cur_g = cur_g->base_graph;
 673
 674                 if (cur_g) {
 675                         *pos = lex_index + cur_g->num_commits_in_base;
 676                         return 1;
 677                 }
 678
 679                 return 0;
 680         }
 681 }
 682
 683 static int parse_commit_in_graph_one(struct repository *r,
 684                                      struct commit_graph *g,
 685                                      struct commit *item)
 686 {
 687         uint32_t pos;
 688
 689         if (item->object.parsed)
 690                 return 1;
 691
 692         if (find_commit_in_graph(item, g, &pos))
 693                 return fill_commit_in_graph(r, item, g, pos);
 694
 695         return 0;
 696 }
 697
 698 int parse_commit_in_graph(struct repository *r, struct commit *item)
 699 {
 700         if (!prepare_commit_graph(r))
 701                 return 0;
 702         return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
 703 }
 704
 705 void load_commit_graph_info(struct repository *r, struct commit *item)
 706 {
 707         uint32_t pos;
 708         if (!prepare_commit_graph(r))
 709                 return;
 710         if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
 711                 fill_commit_graph_info(item, r->objects->commit_graph, pos);
 712 }
 713
 714 static struct tree *load_tree_for_commit(struct repository *r,
 715                                          struct commit_graph *g,
 716                                          struct commit *c)
 717 {
 718         struct object_id oid;
 719         const unsigned char *commit_data;
 720
 721         while (c->graph_pos < g->num_commits_in_base)
 722                 g = g->base_graph;
 723
 724         commit_data = g->chunk_commit_data +
 725                         GRAPH_DATA_WIDTH * (c->graph_pos - g->num_commits_in_base);
 726
 727         hashcpy(oid.hash, commit_data);
 728         set_commit_tree(c, lookup_tree(r, &oid));
 729
 730         return c->maybe_tree;
 731 }
 732
 733 static struct tree *get_commit_tree_in_graph_one(struct repository *r,
 734                                                  struct commit_graph *g,
 735                                                  const struct commit *c)
 736 {
 737         if (c->maybe_tree)
 738                 return c->maybe_tree;
 739         if (c->graph_pos == COMMIT_NOT_FROM_GRAPH)
 740                 BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
 741
 742         return load_tree_for_commit(r, g, (struct commit *)c);
 743 }
 744
 745 struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
 746 {
 747         return get_commit_tree_in_graph_one(r, r->objects->commit_graph, c);
 748 }
 749
 750 struct packed_commit_list {
 751         struct commit **list;
 752         int nr;
 753         int alloc;
 754 };
 755
 756 struct packed_oid_list {
 757         struct object_id *list;
 758         int nr;
 759         int alloc;
 760 };
 761
 762 struct write_commit_graph_context {
 763         struct repository *r;
 764         char *obj_dir;
 765         char *graph_name;
 766         struct packed_oid_list oids;
 767         struct packed_commit_list commits;
 768         int num_extra_edges;
 769         unsigned long approx_nr_objects;
 770         struct progress *progress;
 771         int progress_done;
 772         uint64_t progress_cnt;
 773
 774         char *base_graph_name;
 775         int num_commit_graphs_before;
 776         int num_commit_graphs_after;
 777         char **commit_graph_filenames_before;
 778         char **commit_graph_filenames_after;
 779         char **commit_graph_hash_after;
 780         uint32_t new_num_commits_in_base;
 781         struct commit_graph *new_base_graph;
 782
 783         unsigned append:1,
 784                  report_progress:1,
 785                  split:1,
 786                  check_oids:1;
 787
 788         const struct split_commit_graph_opts *split_opts;
 789 };
 790
 791 static void write_graph_chunk_fanout(struct hashfile *f,
 792                                      struct write_commit_graph_context *ctx)
 793 {
 794         int i, count = 0;
 795         struct commit **list = ctx->commits.list;
 796
 797         /*
 798          * Write the first-level table (the list is sorted,
 799          * but we use a 256-entry lookup to be able to avoid
 800          * having to do eight extra binary search iterations).
 801          */
 802         for (i = 0; i < 256; i++) {
 803                 while (count < ctx->commits.nr) {
 804                         if ((*list)->object.oid.hash[0] != i)
 805                                 break;
 806                         display_progress(ctx->progress, ++ctx->progress_cnt);
 807                         count++;
 808                         list++;
 809                 }
 810
 811                 hashwrite_be32(f, count);
 812         }
 813 }
 814
 815 static void write_graph_chunk_oids(struct hashfile *f, int hash_len,
 816                                    struct write_commit_graph_context *ctx)
 817 {
 818         struct commit **list = ctx->commits.list;
 819         int count;
 820         for (count = 0; count < ctx->commits.nr; count++, list++) {
 821                 display_progress(ctx->progress, ++ctx->progress_cnt);
 822                 hashwrite(f, (*list)->object.oid.hash, (int)hash_len);
 823         }
 824 }
 825
 826 static const unsigned char *commit_to_sha1(size_t index, void *table)
 827 {
 828         struct commit **commits = table;
 829         return commits[index]->object.oid.hash;
 830 }
 831
 832 static void write_graph_chunk_data(struct hashfile *f, int hash_len,
 833                                    struct write_commit_graph_context *ctx)
 834 {
 835         struct commit **list = ctx->commits.list;
 836         struct commit **last = ctx->commits.list + ctx->commits.nr;
 837         uint32_t num_extra_edges = 0;
 838
 839         while (list < last) {
 840                 struct commit_list *parent;
 841                 int edge_value;
 842                 uint32_t packedDate[2];
 843                 display_progress(ctx->progress, ++ctx->progress_cnt);
 844
 845                 parse_commit_no_graph(*list);
 846                 hashwrite(f, get_commit_tree_oid(*list)->hash, hash_len);
 847
 848                 parent = (*list)->parents;
 849
 850                 if (!parent)
 851                         edge_value = GRAPH_PARENT_NONE;
 852                 else {
 853                         edge_value = sha1_pos(parent->item->object.oid.hash,
 854                                               ctx->commits.list,
 855                                               ctx->commits.nr,
 856                                               commit_to_sha1);
 857
 858                         if (edge_value >= 0)
 859                                 edge_value += ctx->new_num_commits_in_base;
 860                         else {
 861                                 uint32_t pos;
 862                                 if (find_commit_in_graph(parent->item,
 863                                                          ctx->new_base_graph,
 864                                                          &pos))
 865                                         edge_value = pos;
 866                         }
 867
 868                         if (edge_value < 0)
 869                                 BUG("missing parent %s for commit %s",
 870                                     oid_to_hex(&parent->item->object.oid),
 871                                     oid_to_hex(&(*list)->object.oid));
 872                 }
 873
 874                 hashwrite_be32(f, edge_value);
 875
 876                 if (parent)
 877                         parent = parent->next;
 878
 879                 if (!parent)
 880                         edge_value = GRAPH_PARENT_NONE;
 881                 else if (parent->next)
 882                         edge_value = GRAPH_EXTRA_EDGES_NEEDED | num_extra_edges;
 883                 else {
 884                         edge_value = sha1_pos(parent->item->object.oid.hash,
 885                                               ctx->commits.list,
 886                                               ctx->commits.nr,
 887                                               commit_to_sha1);
 888
 889                         if (edge_value >= 0)
 890                                 edge_value += ctx->new_num_commits_in_base;
 891                         else {
 892                                 uint32_t pos;
 893                                 if (find_commit_in_graph(parent->item,
 894                                                          ctx->new_base_graph,
 895                                                          &pos))
 896                                         edge_value = pos;
 897                         }
 898
 899                         if (edge_value < 0)
 900                                 BUG("missing parent %s for commit %s",
 901                                     oid_to_hex(&parent->item->object.oid),
 902                                     oid_to_hex(&(*list)->object.oid));
 903                 }
 904
 905                 hashwrite_be32(f, edge_value);
 906
 907                 if (edge_value & GRAPH_EXTRA_EDGES_NEEDED) {
 908                         do {
 909                                 num_extra_edges++;
 910                                 parent = parent->next;
 911                         } while (parent);
 912                 }
 913
 914                 if (sizeof((*list)->date) > 4)
 915                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
 916                 else
 917                         packedDate[0] = 0;
 918
 919                 packedDate[0] |= htonl((*list)->generation << 2);
 920
 921                 packedDate[1] = htonl((*list)->date);
 922                 hashwrite(f, packedDate, 8);
 923
 924                 list++;
 925         }
 926 }
 927
 928 static void write_graph_chunk_extra_edges(struct hashfile *f,
 929                                           struct write_commit_graph_context *ctx)
 930 {
 931         struct commit **list = ctx->commits.list;
 932         struct commit **last = ctx->commits.list + ctx->commits.nr;
 933         struct commit_list *parent;
 934
 935         while (list < last) {
 936                 int num_parents = 0;
 937
 938                 display_progress(ctx->progress, ++ctx->progress_cnt);
 939
 940                 for (parent = (*list)->parents; num_parents < 3 && parent;
 941                      parent = parent->next)
 942                         num_parents++;
 943
 944                 if (num_parents <= 2) {
 945                         list++;
 946                         continue;
 947                 }
 948
 949                 /* Since num_parents > 2, this initializer is safe. */
 950                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
 951                         int edge_value = sha1_pos(parent->item->object.oid.hash,
 952                                                   ctx->commits.list,
 953                                                   ctx->commits.nr,
 954                                                   commit_to_sha1);
 955
 956                         if (edge_value >= 0)
 957                                 edge_value += ctx->new_num_commits_in_base;
 958                         else {
 959                                 uint32_t pos;
 960                                 if (find_commit_in_graph(parent->item,
 961                                                          ctx->new_base_graph,
 962                                                          &pos))
 963                                         edge_value = pos;
 964                         }
 965
 966                         if (edge_value < 0)
 967                                 BUG("missing parent %s for commit %s",
 968                                     oid_to_hex(&parent->item->object.oid),
 969                                     oid_to_hex(&(*list)->object.oid));
 970                         else if (!parent->next)
 971                                 edge_value |= GRAPH_LAST_EDGE;
 972
 973                         hashwrite_be32(f, edge_value);
 974                 }
 975
 976                 list++;
 977         }
 978 }
 979
 980 static int oid_compare(const void *_a, const void *_b)
 981 {
 982         const struct object_id *a = (const struct object_id *)_a;
 983         const struct object_id *b = (const struct object_id *)_b;
 984         return oidcmp(a, b);
 985 }
 986
 987 static int add_packed_commits(const struct object_id *oid,
 988                               struct packed_git *pack,
 989                               uint32_t pos,
 990                               void *data)
 991 {
 992         struct write_commit_graph_context *ctx = (struct write_commit_graph_context*)data;
 993         enum object_type type;
 994         off_t offset = nth_packed_object_offset(pack, pos);
 995         struct object_info oi = OBJECT_INFO_INIT;
 996
 997         if (ctx->progress)
 998                 display_progress(ctx->progress, ++ctx->progress_done);
 999
1000         oi.typep = &type;
1001         if (packed_object_info(ctx->r, pack, offset, &oi) < 0)
1002                 die(_("unable to get type of object %s"), oid_to_hex(oid));
1003
1004         if (type != OBJ_COMMIT)
1005                 return 0;
1006
1007         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1008         oidcpy(&(ctx->oids.list[ctx->oids.nr]), oid);
1009         ctx->oids.nr++;
1010
1011         return 0;
1012 }
1013
1014 static void add_missing_parents(struct write_commit_graph_context *ctx, struct commit *commit)
1015 {
1016         struct commit_list *parent;
1017         for (parent = commit->parents; parent; parent = parent->next) {
1018                 if (!(parent->item->object.flags & UNINTERESTING)) {
1019                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1020                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(parent->item->object.oid));
1021                         ctx->oids.nr++;
1022                         parent->item->object.flags |= UNINTERESTING;
1023                 }
1024         }
1025 }
1026
1027 static void close_reachable(struct write_commit_graph_context *ctx)
1028 {
1029         int i;
1030         struct commit *commit;
1031
1032         if (ctx->report_progress)
1033                 ctx->progress = start_delayed_progress(
1034                                         _("Loading known commits in commit graph"),
1035                                         ctx->oids.nr);
1036         for (i = 0; i < ctx->oids.nr; i++) {
1037                 display_progress(ctx->progress, i + 1);
1038                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1039                 if (commit)
1040                         commit->object.flags |= UNINTERESTING;
1041         }
1042         stop_progress(&ctx->progress);
1043
1044         /*
1045          * As this loop runs, ctx->oids.nr may grow, but not more
1046          * than the number of missing commits in the reachable
1047          * closure.
1048          */
1049         if (ctx->report_progress)
1050                 ctx->progress = start_delayed_progress(
1051                                         _("Expanding reachable commits in commit graph"),
1052                                         ctx->oids.nr);
1053         for (i = 0; i < ctx->oids.nr; i++) {
1054                 display_progress(ctx->progress, i + 1);
1055                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1056
1057                 if (!commit)
1058                         continue;
1059                 if (ctx->split) {
1060                         if (!parse_commit(commit) &&
1061                             commit->graph_pos == COMMIT_NOT_FROM_GRAPH)
1062                                 add_missing_parents(ctx, commit);
1063                 } else if (!parse_commit_no_graph(commit))
1064                         add_missing_parents(ctx, commit);
1065         }
1066         stop_progress(&ctx->progress);
1067
1068         if (ctx->report_progress)
1069                 ctx->progress = start_delayed_progress(
1070                                         _("Clearing commit marks in commit graph"),
1071                                         ctx->oids.nr);
1072         for (i = 0; i < ctx->oids.nr; i++) {
1073                 display_progress(ctx->progress, i + 1);
1074                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
1075
1076                 if (commit)
1077                         commit->object.flags &= ~UNINTERESTING;
1078         }
1079         stop_progress(&ctx->progress);
1080 }
1081
1082 static void compute_generation_numbers(struct write_commit_graph_context *ctx)
1083 {
1084         int i;
1085         struct commit_list *list = NULL;
1086
1087         if (ctx->report_progress)
1088                 ctx->progress = start_progress(
1089                                         _("Computing commit graph generation numbers"),
1090                                         ctx->commits.nr);
1091         for (i = 0; i < ctx->commits.nr; i++) {
1092                 display_progress(ctx->progress, i + 1);
1093                 if (ctx->commits.list[i]->generation != GENERATION_NUMBER_INFINITY &&
1094                     ctx->commits.list[i]->generation != GENERATION_NUMBER_ZERO)
1095                         continue;
1096
1097                 commit_list_insert(ctx->commits.list[i], &list);
1098                 while (list) {
1099                         struct commit *current = list->item;
1100                         struct commit_list *parent;
1101                         int all_parents_computed = 1;
1102                         uint32_t max_generation = 0;
1103
1104                         for (parent = current->parents; parent; parent = parent->next) {
1105                                 if (parent->item->generation == GENERATION_NUMBER_INFINITY ||
1106                                     parent->item->generation == GENERATION_NUMBER_ZERO) {
1107                                         all_parents_computed = 0;
1108                                         commit_list_insert(parent->item, &list);
1109                                         break;
1110                                 } else if (parent->item->generation > max_generation) {
1111                                         max_generation = parent->item->generation;
1112                                 }
1113                         }
1114
1115                         if (all_parents_computed) {
1116                                 current->generation = max_generation + 1;
1117                                 pop_commit(&list);
1118
1119                                 if (current->generation > GENERATION_NUMBER_MAX)
1120                                         current->generation = GENERATION_NUMBER_MAX;
1121                         }
1122                 }
1123         }
1124         stop_progress(&ctx->progress);
1125 }
1126
1127 static int add_ref_to_list(const char *refname,
1128                            const struct object_id *oid,
1129                            int flags, void *cb_data)
1130 {
1131         struct string_list *list = (struct string_list *)cb_data;
1132
1133         string_list_append(list, oid_to_hex(oid));
1134         return 0;
1135 }
1136
1137 int write_commit_graph_reachable(const char *obj_dir,
1138                                  enum commit_graph_write_flags flags,
1139                                  const struct split_commit_graph_opts *split_opts)
1140 {
1141         struct string_list list = STRING_LIST_INIT_DUP;
1142         int result;
1143
1144         for_each_ref(add_ref_to_list, &list);
1145         result = write_commit_graph(obj_dir, NULL, &list,
1146                                     flags, split_opts);
1147
1148         string_list_clear(&list, 0);
1149         return result;
1150 }
1151
1152 static int fill_oids_from_packs(struct write_commit_graph_context *ctx,
1153                                 struct string_list *pack_indexes)
1154 {
1155         uint32_t i;
1156         struct strbuf progress_title = STRBUF_INIT;
1157         struct strbuf packname = STRBUF_INIT;
1158         int dirlen;
1159
1160         strbuf_addf(&packname, "%s/pack/", ctx->obj_dir);
1161         dirlen = packname.len;
1162         if (ctx->report_progress) {
1163                 strbuf_addf(&progress_title,
1164                             Q_("Finding commits for commit graph in %d pack",
1165                                "Finding commits for commit graph in %d packs",
1166                                pack_indexes->nr),
1167                             pack_indexes->nr);
1168                 ctx->progress = start_delayed_progress(progress_title.buf, 0);
1169                 ctx->progress_done = 0;
1170         }
1171         for (i = 0; i < pack_indexes->nr; i++) {
1172                 struct packed_git *p;
1173                 strbuf_setlen(&packname, dirlen);
1174                 strbuf_addstr(&packname, pack_indexes->items[i].string);
1175                 p = add_packed_git(packname.buf, packname.len, 1);
1176                 if (!p) {
1177                         error(_("error adding pack %s"), packname.buf);
1178                         return -1;
1179                 }
1180                 if (open_pack_index(p)) {
1181                         error(_("error opening index for %s"), packname.buf);
1182                         return -1;
1183                 }
1184                 for_each_object_in_pack(p, add_packed_commits, ctx,
1185                                         FOR_EACH_OBJECT_PACK_ORDER);
1186                 close_pack(p);
1187                 free(p);
1188         }
1189
1190         stop_progress(&ctx->progress);
1191         strbuf_reset(&progress_title);
1192         strbuf_release(&packname);
1193
1194         return 0;
1195 }
1196
1197 static int fill_oids_from_commit_hex(struct write_commit_graph_context *ctx,
1198                                      struct string_list *commit_hex)
1199 {
1200         uint32_t i;
1201         struct strbuf progress_title = STRBUF_INIT;
1202
1203         if (ctx->report_progress) {
1204                 strbuf_addf(&progress_title,
1205                             Q_("Finding commits for commit graph from %d ref",
1206                                "Finding commits for commit graph from %d refs",
1207                                commit_hex->nr),
1208                             commit_hex->nr);
1209                 ctx->progress = start_delayed_progress(
1210                                         progress_title.buf,
1211                                         commit_hex->nr);
1212         }
1213         for (i = 0; i < commit_hex->nr; i++) {
1214                 const char *end;
1215                 struct object_id oid;
1216                 struct commit *result;
1217
1218                 display_progress(ctx->progress, i + 1);
1219                 if (!parse_oid_hex(commit_hex->items[i].string, &oid, &end) &&
1220                     (result = lookup_commit_reference_gently(ctx->r, &oid, 1))) {
1221                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
1222                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(result->object.oid));
1223                         ctx->oids.nr++;
1224                 } else if (ctx->check_oids) {
1225                         error(_("invalid commit object id: %s"),
1226                             commit_hex->items[i].string);
1227                         return -1;
1228                 }
1229         }
1230         stop_progress(&ctx->progress);
1231         strbuf_release(&progress_title);
1232
1233         return 0;
1234 }
1235
1236 static void fill_oids_from_all_packs(struct write_commit_graph_context *ctx)
1237 {
1238         if (ctx->report_progress)
1239                 ctx->progress = start_delayed_progress(
1240                         _("Finding commits for commit graph among packed objects"),
1241                         ctx->approx_nr_objects);
1242         for_each_packed_object(add_packed_commits, ctx,
1243                                FOR_EACH_OBJECT_PACK_ORDER);
1244         if (ctx->progress_done < ctx->approx_nr_objects)
1245                 display_progress(ctx->progress, ctx->approx_nr_objects);
1246         stop_progress(&ctx->progress);
1247 }
1248
1249 static uint32_t count_distinct_commits(struct write_commit_graph_context *ctx)
1250 {
1251         uint32_t i, count_distinct = 1;
1252
1253         if (ctx->report_progress)
1254                 ctx->progress = start_delayed_progress(
1255                         _("Counting distinct commits in commit graph"),
1256                         ctx->oids.nr);
1257         display_progress(ctx->progress, 0); /* TODO: Measure QSORT() progress */
1258         QSORT(ctx->oids.list, ctx->oids.nr, oid_compare);
1259
1260         for (i = 1; i < ctx->oids.nr; i++) {
1261                 display_progress(ctx->progress, i + 1);
1262                 if (!oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i])) {
1263                         if (ctx->split) {
1264                                 struct commit *c = lookup_commit(ctx->r, &ctx->oids.list[i]);
1265
1266                                 if (!c || c->graph_pos != COMMIT_NOT_FROM_GRAPH)
1267                                         continue;
1268                         }
1269
1270                         count_distinct++;
1271                 }
1272         }
1273         stop_progress(&ctx->progress);
1274
1275         return count_distinct;
1276 }
1277
1278 static void copy_oids_to_commits(struct write_commit_graph_context *ctx)
1279 {
1280         uint32_t i;
1281         struct commit_list *parent;
1282
1283         ctx->num_extra_edges = 0;
1284         if (ctx->report_progress)
1285                 ctx->progress = start_delayed_progress(
1286                         _("Finding extra edges in commit graph"),
1287                         ctx->oids.nr);
1288         for (i = 0; i < ctx->oids.nr; i++) {
1289                 int num_parents = 0;
1290                 display_progress(ctx->progress, i + 1);
1291                 if (i > 0 && oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i]))
1292                         continue;
1293
1294                 ALLOC_GROW(ctx->commits.list, ctx->commits.nr + 1, ctx->commits.alloc);
1295                 ctx->commits.list[ctx->commits.nr] = lookup_commit(ctx->r, &ctx->oids.list[i]);
1296
1297                 if (ctx->split &&
1298                     ctx->commits.list[ctx->commits.nr]->graph_pos != COMMIT_NOT_FROM_GRAPH)
1299                         continue;
1300
1301                 parse_commit_no_graph(ctx->commits.list[ctx->commits.nr]);
1302
1303                 for (parent = ctx->commits.list[ctx->commits.nr]->parents;
1304                      parent; parent = parent->next)
1305                         num_parents++;
1306
1307                 if (num_parents > 2)
1308                         ctx->num_extra_edges += num_parents - 1;
1309
1310                 ctx->commits.nr++;
1311         }
1312         stop_progress(&ctx->progress);
1313 }
1314
1315 static int write_graph_chunk_base_1(struct hashfile *f,
1316                                     struct commit_graph *g)
1317 {
1318         int num = 0;
1319
1320         if (!g)
1321                 return 0;
1322
1323         num = write_graph_chunk_base_1(f, g->base_graph);
1324         hashwrite(f, g->oid.hash, the_hash_algo->rawsz);
1325         return num + 1;
1326 }
1327
1328 static int write_graph_chunk_base(struct hashfile *f,
1329                                   struct write_commit_graph_context *ctx)
1330 {
1331         int num = write_graph_chunk_base_1(f, ctx->new_base_graph);
1332
1333         if (num != ctx->num_commit_graphs_after - 1) {
1334                 error(_("failed to write correct number of base graph ids"));
1335                 return -1;
1336         }
1337
1338         return 0;
1339 }
1340
1341 static int write_commit_graph_file(struct write_commit_graph_context *ctx)
1342 {
1343         uint32_t i;
1344         int fd;
1345         struct hashfile *f;
1346         struct lock_file lk = LOCK_INIT;
1347         uint32_t chunk_ids[6];
1348         uint64_t chunk_offsets[6];
1349         const unsigned hashsz = the_hash_algo->rawsz;
1350         struct strbuf progress_title = STRBUF_INIT;
1351         int num_chunks = 3;
1352         struct object_id file_hash;
1353
1354         if (ctx->split) {
1355                 struct strbuf tmp_file = STRBUF_INIT;
1356
1357                 strbuf_addf(&tmp_file,
1358                             "%s/info/commit-graphs/tmp_graph_XXXXXX",
1359                             ctx->obj_dir);
1360                 ctx->graph_name = strbuf_detach(&tmp_file, NULL);
1361         } else {
1362                 ctx->graph_name = get_commit_graph_filename(ctx->obj_dir);
1363         }
1364
1365         if (safe_create_leading_directories(ctx->graph_name)) {
1366                 UNLEAK(ctx->graph_name);
1367                 error(_("unable to create leading directories of %s"),
1368                         ctx->graph_name);
1369                 return -1;
1370         }
1371
1372         if (ctx->split) {
1373                 char *lock_name = get_chain_filename(ctx->obj_dir);
1374
1375                 hold_lock_file_for_update(&lk, lock_name, LOCK_DIE_ON_ERROR);
1376
1377                 fd = git_mkstemp_mode(ctx->graph_name, 0444);
1378                 if (fd < 0) {
1379                         error(_("unable to create '%s'"), ctx->graph_name);
1380                         return -1;
1381                 }
1382
1383                 f = hashfd(fd, ctx->graph_name);
1384         } else {
1385                 hold_lock_file_for_update(&lk, ctx->graph_name, LOCK_DIE_ON_ERROR);
1386                 fd = lk.tempfile->fd;
1387                 f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
1388         }
1389
1390         chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
1391         chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
1392         chunk_ids[2] = GRAPH_CHUNKID_DATA;
1393         if (ctx->num_extra_edges) {
1394                 chunk_ids[num_chunks] = GRAPH_CHUNKID_EXTRAEDGES;
1395                 num_chunks++;
1396         }
1397         if (ctx->num_commit_graphs_after > 1) {
1398                 chunk_ids[num_chunks] = GRAPH_CHUNKID_BASE;
1399                 num_chunks++;
1400         }
1401
1402         chunk_ids[num_chunks] = 0;
1403
1404         chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
1405         chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
1406         chunk_offsets[2] = chunk_offsets[1] + hashsz * ctx->commits.nr;
1407         chunk_offsets[3] = chunk_offsets[2] + (hashsz + 16) * ctx->commits.nr;
1408
1409         num_chunks = 3;
1410         if (ctx->num_extra_edges) {
1411                 chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
1412                                                 4 * ctx->num_extra_edges;
1413                 num_chunks++;
1414         }
1415         if (ctx->num_commit_graphs_after > 1) {
1416                 chunk_offsets[num_chunks + 1] = chunk_offsets[num_chunks] +
1417                                                 hashsz * (ctx->num_commit_graphs_after - 1);
1418                 num_chunks++;
1419         }
1420
1421         hashwrite_be32(f, GRAPH_SIGNATURE);
1422
1423         hashwrite_u8(f, GRAPH_VERSION);
1424         hashwrite_u8(f, oid_version());
1425         hashwrite_u8(f, num_chunks);
1426         hashwrite_u8(f, ctx->num_commit_graphs_after - 1);
1427
1428         for (i = 0; i <= num_chunks; i++) {
1429                 uint32_t chunk_write[3];
1430
1431                 chunk_write[0] = htonl(chunk_ids[i]);
1432                 chunk_write[1] = htonl(chunk_offsets[i] >> 32);
1433                 chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
1434                 hashwrite(f, chunk_write, 12);
1435         }
1436
1437         if (ctx->report_progress) {
1438                 strbuf_addf(&progress_title,
1439                             Q_("Writing out commit graph in %d pass",
1440                                "Writing out commit graph in %d passes",
1441                                num_chunks),
1442                             num_chunks);
1443                 ctx->progress = start_delayed_progress(
1444                         progress_title.buf,
1445                         num_chunks * ctx->commits.nr);
1446         }
1447         write_graph_chunk_fanout(f, ctx);
1448         write_graph_chunk_oids(f, hashsz, ctx);
1449         write_graph_chunk_data(f, hashsz, ctx);
1450         if (ctx->num_extra_edges)
1451                 write_graph_chunk_extra_edges(f, ctx);
1452         if (ctx->num_commit_graphs_after > 1 &&
1453             write_graph_chunk_base(f, ctx)) {
1454                 return -1;
1455         }
1456         stop_progress(&ctx->progress);
1457         strbuf_release(&progress_title);
1458
1459         if (ctx->split && ctx->base_graph_name && ctx->num_commit_graphs_after > 1) {
1460                 char *new_base_hash = xstrdup(oid_to_hex(&ctx->new_base_graph->oid));
1461                 char *new_base_name = get_split_graph_filename(ctx->new_base_graph->obj_dir, new_base_hash);
1462
1463                 free(ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2]);
1464                 free(ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2]);
1465                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2] = new_base_name;
1466                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2] = new_base_hash;
1467         }
1468
1469         close_commit_graph(ctx->r->objects);
1470         finalize_hashfile(f, file_hash.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
1471
1472         if (ctx->split) {
1473                 FILE *chainf = fdopen_lock_file(&lk, "w");
1474                 char *final_graph_name;
1475                 int result;
1476
1477                 close(fd);
1478
1479                 if (!chainf) {
1480                         error(_("unable to open commit-graph chain file"));
1481                         return -1;
1482                 }
1483
1484                 if (ctx->base_graph_name) {
1485                         const char *dest = ctx->commit_graph_filenames_after[
1486                                                 ctx->num_commit_graphs_after - 2];
1487
1488                         if (strcmp(ctx->base_graph_name, dest)) {
1489                                 result = rename(ctx->base_graph_name, dest);
1490
1491                                 if (result) {
1492                                         error(_("failed to rename base commit-graph file"));
1493                                         return -1;
1494                                 }
1495                         }
1496                 } else {
1497                         char *graph_name = get_commit_graph_filename(ctx->obj_dir);
1498                         unlink(graph_name);
1499                 }
1500
1501                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(oid_to_hex(&file_hash));
1502                 final_graph_name = get_split_graph_filename(ctx->obj_dir,
1503                                         ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
1504                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1] = final_graph_name;
1505
1506                 result = rename(ctx->graph_name, final_graph_name);
1507
1508                 for (i = 0; i < ctx->num_commit_graphs_after; i++)
1509                         fprintf(lk.tempfile->fp, "%s\n", ctx->commit_graph_hash_after[i]);
1510
1511                 if (result) {
1512                         error(_("failed to rename temporary commit-graph file"));
1513                         return -1;
1514                 }
1515         }
1516
1517         commit_lock_file(&lk);
1518
1519         return 0;
1520 }
1521
1522 static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
1523 {
1524         struct commit_graph *g = ctx->r->objects->commit_graph;
1525         uint32_t num_commits = ctx->commits.nr;
1526         uint32_t i;
1527
1528         int max_commits = 0;
1529         int size_mult = 2;
1530
1531         if (ctx->split_opts) {
1532                 max_commits = ctx->split_opts->max_commits;
1533                 size_mult = ctx->split_opts->size_multiple;
1534         }
1535
1536         g = ctx->r->objects->commit_graph;
1537         ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1;
1538
1539         while (g && (g->num_commits <= size_mult * num_commits ||
1540                     (max_commits && num_commits > max_commits))) {
1541                 if (strcmp(g->obj_dir, ctx->obj_dir))
1542                         break;
1543
1544                 num_commits += g->num_commits;
1545                 g = g->base_graph;
1546
1547                 ctx->num_commit_graphs_after--;
1548         }
1549
1550         ctx->new_base_graph = g;
1551
1552         if (ctx->num_commit_graphs_after == 2) {
1553                 char *old_graph_name = get_commit_graph_filename(g->obj_dir);
1554
1555                 if (!strcmp(g->filename, old_graph_name) &&
1556                     strcmp(g->obj_dir, ctx->obj_dir)) {
1557                         ctx->num_commit_graphs_after = 1;
1558                         ctx->new_base_graph = NULL;
1559                 }
1560
1561                 free(old_graph_name);
1562         }
1563
1564         ALLOC_ARRAY(ctx->commit_graph_filenames_after, ctx->num_commit_graphs_after);
1565         ALLOC_ARRAY(ctx->commit_graph_hash_after, ctx->num_commit_graphs_after);
1566
1567         for (i = 0; i < ctx->num_commit_graphs_after &&
1568                     i < ctx->num_commit_graphs_before; i++)
1569                 ctx->commit_graph_filenames_after[i] = xstrdup(ctx->commit_graph_filenames_before[i]);
1570
1571         i = ctx->num_commit_graphs_before - 1;
1572         g = ctx->r->objects->commit_graph;
1573
1574         while (g) {
1575                 if (i < ctx->num_commit_graphs_after)
1576                         ctx->commit_graph_hash_after[i] = xstrdup(oid_to_hex(&g->oid));
1577
1578                 i--;
1579                 g = g->base_graph;
1580         }
1581 }
1582
1583 static void merge_commit_graph(struct write_commit_graph_context *ctx,
1584                                struct commit_graph *g)
1585 {
1586         uint32_t i;
1587         uint32_t offset = g->num_commits_in_base;
1588
1589         ALLOC_GROW(ctx->commits.list, ctx->commits.nr + g->num_commits, ctx->commits.alloc);
1590
1591         for (i = 0; i < g->num_commits; i++) {
1592                 struct object_id oid;
1593                 struct commit *result;
1594
1595                 display_progress(ctx->progress, i + 1);
1596
1597                 load_oid_from_graph(g, i + offset, &oid);
1598
1599                 /* only add commits if they still exist in the repo */
1600                 result = lookup_commit_reference_gently(ctx->r, &oid, 1);
1601
1602                 if (result) {
1603                         ctx->commits.list[ctx->commits.nr] = result;
1604                         ctx->commits.nr++;
1605                 }
1606         }
1607 }
1608
1609 static int commit_compare(const void *_a, const void *_b)
1610 {
1611         const struct commit *a = *(const struct commit **)_a;
1612         const struct commit *b = *(const struct commit **)_b;
1613         return oidcmp(&a->object.oid, &b->object.oid);
1614 }
1615
1616 static void sort_and_scan_merged_commits(struct write_commit_graph_context *ctx)
1617 {
1618         uint32_t i, num_parents;
1619         struct commit_list *parent;
1620
1621         if (ctx->report_progress)
1622                 ctx->progress = start_delayed_progress(
1623                                         _("Scanning merged commits"),
1624                                         ctx->commits.nr);
1625
1626         QSORT(ctx->commits.list, ctx->commits.nr, commit_compare);
1627
1628         ctx->num_extra_edges = 0;
1629         for (i = 0; i < ctx->commits.nr; i++) {
1630                 display_progress(ctx->progress, i);
1631
1632                 if (i && oideq(&ctx->commits.list[i - 1]->object.oid,
1633                           &ctx->commits.list[i]->object.oid)) {
1634                         die(_("unexpected duplicate commit id %s"),
1635                             oid_to_hex(&ctx->commits.list[i]->object.oid));
1636                 } else {
1637                         num_parents = 0;
1638                         for (parent = ctx->commits.list[i]->parents; parent; parent = parent->next)
1639                                 num_parents++;
1640
1641                         if (num_parents > 2)
1642                                 ctx->num_extra_edges += num_parents - 2;
1643                 }
1644         }
1645
1646         stop_progress(&ctx->progress);
1647 }
1648
1649 static void merge_commit_graphs(struct write_commit_graph_context *ctx)
1650 {
1651         struct commit_graph *g = ctx->r->objects->commit_graph;
1652         uint32_t current_graph_number = ctx->num_commit_graphs_before;
1653         struct strbuf progress_title = STRBUF_INIT;
1654
1655         while (g && current_graph_number >= ctx->num_commit_graphs_after) {
1656                 current_graph_number--;
1657
1658                 if (ctx->report_progress) {
1659                         strbuf_addstr(&progress_title, _("Merging commit-graph"));
1660                         ctx->progress = start_delayed_progress(progress_title.buf, 0);
1661                 }
1662
1663                 merge_commit_graph(ctx, g);
1664                 stop_progress(&ctx->progress);
1665                 strbuf_release(&progress_title);
1666
1667                 g = g->base_graph;
1668         }
1669
1670         if (g) {
1671                 ctx->new_base_graph = g;
1672                 ctx->new_num_commits_in_base = g->num_commits + g->num_commits_in_base;
1673         }
1674
1675         if (ctx->new_base_graph)
1676                 ctx->base_graph_name = xstrdup(ctx->new_base_graph->filename);
1677
1678         sort_and_scan_merged_commits(ctx);
1679 }
1680
1681 static void mark_commit_graphs(struct write_commit_graph_context *ctx)
1682 {
1683         uint32_t i;
1684         time_t now = time(NULL);
1685
1686         for (i = ctx->num_commit_graphs_after - 1; i < ctx->num_commit_graphs_before; i++) {
1687                 struct stat st;
1688                 struct utimbuf updated_time;
1689
1690                 stat(ctx->commit_graph_filenames_before[i], &st);
1691
1692                 updated_time.actime = st.st_atime;
1693                 updated_time.modtime = now;
1694                 utime(ctx->commit_graph_filenames_before[i], &updated_time);
1695         }
1696 }
1697
1698 static void expire_commit_graphs(struct write_commit_graph_context *ctx)
1699 {
1700         struct strbuf path = STRBUF_INIT;
1701         DIR *dir;
1702         struct dirent *de;
1703         size_t dirnamelen;
1704         timestamp_t expire_time = time(NULL);
1705
1706         if (ctx->split_opts && ctx->split_opts->expire_time)
1707                 expire_time -= ctx->split_opts->expire_time;
1708         if (!ctx->split) {
1709                 char *chain_file_name = get_chain_filename(ctx->obj_dir);
1710                 unlink(chain_file_name);
1711                 free(chain_file_name);
1712                 ctx->num_commit_graphs_after = 0;
1713         }
1714
1715         strbuf_addstr(&path, ctx->obj_dir);
1716         strbuf_addstr(&path, "/info/commit-graphs");
1717         dir = opendir(path.buf);
1718
1719         if (!dir) {
1720                 strbuf_release(&path);
1721                 return;
1722         }
1723
1724         strbuf_addch(&path, '/');
1725         dirnamelen = path.len;
1726         while ((de = readdir(dir)) != NULL) {
1727                 struct stat st;
1728                 uint32_t i, found = 0;
1729
1730                 strbuf_setlen(&path, dirnamelen);
1731                 strbuf_addstr(&path, de->d_name);
1732
1733                 stat(path.buf, &st);
1734
1735                 if (st.st_mtime > expire_time)
1736                         continue;
1737                 if (path.len < 6 || strcmp(path.buf + path.len - 6, ".graph"))
1738                         continue;
1739
1740                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
1741                         if (!strcmp(ctx->commit_graph_filenames_after[i],
1742                                     path.buf)) {
1743                                 found = 1;
1744                                 break;
1745                         }
1746                 }
1747
1748                 if (!found)
1749                         unlink(path.buf);
1750         }
1751 }
1752
1753 int write_commit_graph(const char *obj_dir,
1754                        struct string_list *pack_indexes,
1755                        struct string_list *commit_hex,
1756                        enum commit_graph_write_flags flags,
1757                        const struct split_commit_graph_opts *split_opts)
1758 {
1759         struct write_commit_graph_context *ctx;
1760         uint32_t i, count_distinct = 0;
1761         size_t len;
1762         int res = 0;
1763
1764         if (!commit_graph_compatible(the_repository))
1765                 return 0;
1766
1767         ctx = xcalloc(1, sizeof(struct write_commit_graph_context));
1768         ctx->r = the_repository;
1769
1770         /* normalize object dir with no trailing slash */
1771         ctx->obj_dir = xmallocz(strlen(obj_dir) + 1);
1772         normalize_path_copy(ctx->obj_dir, obj_dir);
1773         len = strlen(ctx->obj_dir);
1774         if (len && ctx->obj_dir[len - 1] == '/')
1775                 ctx->obj_dir[len - 1] = 0;
1776
1777         ctx->append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0;
1778         ctx->report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0;
1779         ctx->split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
1780         ctx->check_oids = flags & COMMIT_GRAPH_WRITE_CHECK_OIDS ? 1 : 0;
1781         ctx->split_opts = split_opts;
1782
1783         if (ctx->split) {
1784                 struct commit_graph *g;
1785                 prepare_commit_graph(ctx->r);
1786
1787                 g = ctx->r->objects->commit_graph;
1788
1789                 while (g) {
1790                         ctx->num_commit_graphs_before++;
1791                         g = g->base_graph;
1792                 }
1793
1794                 if (ctx->num_commit_graphs_before) {
1795                         ALLOC_ARRAY(ctx->commit_graph_filenames_before, ctx->num_commit_graphs_before);
1796                         i = ctx->num_commit_graphs_before;
1797                         g = ctx->r->objects->commit_graph;
1798
1799                         while (g) {
1800                                 ctx->commit_graph_filenames_before[--i] = xstrdup(g->filename);
1801                                 g = g->base_graph;
1802                         }
1803                 }
1804         }
1805
1806         ctx->approx_nr_objects = approximate_object_count();
1807         ctx->oids.alloc = ctx->approx_nr_objects / 32;
1808
1809         if (ctx->split && split_opts && ctx->oids.alloc > split_opts->max_commits)
1810                 ctx->oids.alloc = split_opts->max_commits;
1811
1812         if (ctx->append) {
1813                 prepare_commit_graph_one(ctx->r, ctx->obj_dir);
1814                 if (ctx->r->objects->commit_graph)
1815                         ctx->oids.alloc += ctx->r->objects->commit_graph->num_commits;
1816         }
1817
1818         if (ctx->oids.alloc < 1024)
1819                 ctx->oids.alloc = 1024;
1820         ALLOC_ARRAY(ctx->oids.list, ctx->oids.alloc);
1821
1822         if (ctx->append && ctx->r->objects->commit_graph) {
1823                 struct commit_graph *g = ctx->r->objects->commit_graph;
1824                 for (i = 0; i < g->num_commits; i++) {
1825                         const unsigned char *hash = g->chunk_oid_lookup + g->hash_len * i;
1826                         hashcpy(ctx->oids.list[ctx->oids.nr++].hash, hash);
1827                 }
1828         }
1829
1830         if (pack_indexes) {
1831                 if ((res = fill_oids_from_packs(ctx, pack_indexes)))
1832                         goto cleanup;
1833         }
1834
1835         if (commit_hex) {
1836                 if ((res = fill_oids_from_commit_hex(ctx, commit_hex)))
1837                         goto cleanup;
1838         }
1839
1840         if (!pack_indexes && !commit_hex)
1841                 fill_oids_from_all_packs(ctx);
1842
1843         close_reachable(ctx);
1844
1845         count_distinct = count_distinct_commits(ctx);
1846
1847         if (count_distinct >= GRAPH_EDGE_LAST_MASK) {
1848                 error(_("the commit graph format cannot write %d commits"), count_distinct);
1849                 res = -1;
1850                 goto cleanup;
1851         }
1852
1853         ctx->commits.alloc = count_distinct;
1854         ALLOC_ARRAY(ctx->commits.list, ctx->commits.alloc);
1855
1856         copy_oids_to_commits(ctx);
1857
1858         if (ctx->commits.nr >= GRAPH_EDGE_LAST_MASK) {
1859                 error(_("too many commits to write graph"));
1860                 res = -1;
1861                 goto cleanup;
1862         }
1863
1864         if (!ctx->commits.nr)
1865                 goto cleanup;
1866
1867         if (ctx->split) {
1868                 split_graph_merge_strategy(ctx);
1869
1870                 merge_commit_graphs(ctx);
1871         } else
1872                 ctx->num_commit_graphs_after = 1;
1873
1874         compute_generation_numbers(ctx);
1875
1876         res = write_commit_graph_file(ctx);
1877
1878         if (ctx->split)
1879                 mark_commit_graphs(ctx);
1880
1881         expire_commit_graphs(ctx);
1882
1883 cleanup:
1884         free(ctx->graph_name);
1885         free(ctx->commits.list);
1886         free(ctx->oids.list);
1887         free(ctx->obj_dir);
1888
1889         if (ctx->commit_graph_filenames_after) {
1890                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
1891                         free(ctx->commit_graph_filenames_after[i]);
1892                         free(ctx->commit_graph_hash_after[i]);
1893                 }
1894
1895                 for (i = 0; i < ctx->num_commit_graphs_before; i++)
1896                         free(ctx->commit_graph_filenames_before[i]);
1897
1898                 free(ctx->commit_graph_filenames_after);
1899                 free(ctx->commit_graph_filenames_before);
1900                 free(ctx->commit_graph_hash_after);
1901         }
1902
1903         free(ctx);
1904
1905         return res;
1906 }
1907
1908 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
1909 static int verify_commit_graph_error;
1910
1911 static void graph_report(const char *fmt, ...)
1912 {
1913         va_list ap;
1914
1915         verify_commit_graph_error = 1;
1916         va_start(ap, fmt);
1917         vfprintf(stderr, fmt, ap);
1918         fprintf(stderr, "\n");
1919         va_end(ap);
1920 }
1921
1922 #define GENERATION_ZERO_EXISTS 1
1923 #define GENERATION_NUMBER_EXISTS 2
1924
1925 int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
1926 {
1927         uint32_t i, cur_fanout_pos = 0;
1928         struct object_id prev_oid, cur_oid, checksum;
1929         int generation_zero = 0;
1930         struct hashfile *f;
1931         int devnull;
1932         struct progress *progress = NULL;
1933         int local_error = 0;
1934
1935         if (!g) {
1936                 graph_report("no commit-graph file loaded");
1937                 return 1;
1938         }
1939
1940         verify_commit_graph_error = verify_commit_graph_lite(g);
1941         if (verify_commit_graph_error)
1942                 return verify_commit_graph_error;
1943
1944         devnull = open("/dev/null", O_WRONLY);
1945         f = hashfd(devnull, NULL);
1946         hashwrite(f, g->data, g->data_len - g->hash_len);
1947         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
1948         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
1949                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
1950                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
1951         }
1952
1953         for (i = 0; i < g->num_commits; i++) {
1954                 struct commit *graph_commit;
1955
1956                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1957
1958                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
1959                         graph_report(_("commit-graph has incorrect OID order: %s then %s"),
1960                                      oid_to_hex(&prev_oid),
1961                                      oid_to_hex(&cur_oid));
1962
1963                 oidcpy(&prev_oid, &cur_oid);
1964
1965                 while (cur_oid.hash[0] > cur_fanout_pos) {
1966                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1967
1968                         if (i != fanout_value)
1969                                 graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
1970                                              cur_fanout_pos, fanout_value, i);
1971                         cur_fanout_pos++;
1972                 }
1973
1974                 graph_commit = lookup_commit(r, &cur_oid);
1975                 if (!parse_commit_in_graph_one(r, g, graph_commit))
1976                         graph_report(_("failed to parse commit %s from commit-graph"),
1977                                      oid_to_hex(&cur_oid));
1978         }
1979
1980         while (cur_fanout_pos < 256) {
1981                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1982
1983                 if (g->num_commits != fanout_value)
1984                         graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
1985                                      cur_fanout_pos, fanout_value, i);
1986
1987                 cur_fanout_pos++;
1988         }
1989
1990         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
1991                 return verify_commit_graph_error;
1992
1993         progress = start_progress(_("Verifying commits in commit graph"),
1994                                   g->num_commits);
1995         for (i = 0; i < g->num_commits; i++) {
1996                 struct commit *graph_commit, *odb_commit;
1997                 struct commit_list *graph_parents, *odb_parents;
1998                 uint32_t max_generation = 0;
1999
2000                 display_progress(progress, i + 1);
2001                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
2002
2003                 graph_commit = lookup_commit(r, &cur_oid);
2004                 odb_commit = (struct commit *)create_object(r, &cur_oid, alloc_commit_node(r));
2005                 if (parse_commit_internal(odb_commit, 0, 0)) {
2006                         graph_report(_("failed to parse commit %s from object database for commit-graph"),
2007                                      oid_to_hex(&cur_oid));
2008                         continue;
2009                 }
2010
2011                 if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
2012                            get_commit_tree_oid(odb_commit)))
2013                         graph_report(_("root tree OID for commit %s in commit-graph is %s != %s"),
2014                                      oid_to_hex(&cur_oid),
2015                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
2016                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
2017
2018                 graph_parents = graph_commit->parents;
2019                 odb_parents = odb_commit->parents;
2020
2021                 while (graph_parents) {
2022                         if (odb_parents == NULL) {
2023                                 graph_report(_("commit-graph parent list for commit %s is too long"),
2024                                              oid_to_hex(&cur_oid));
2025                                 break;
2026                         }
2027
2028                         /* parse parent in case it is in a base graph */
2029                         parse_commit_in_graph_one(r, g, graph_parents->item);
2030
2031                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
2032                                 graph_report(_("commit-graph parent for %s is %s != %s"),
2033                                              oid_to_hex(&cur_oid),
2034                                              oid_to_hex(&graph_parents->item->object.oid),
2035                                              oid_to_hex(&odb_parents->item->object.oid));
2036
2037                         if (graph_parents->item->generation > max_generation)
2038                                 max_generation = graph_parents->item->generation;
2039
2040                         graph_parents = graph_parents->next;
2041                         odb_parents = odb_parents->next;
2042                 }
2043
2044                 if (odb_parents != NULL)
2045                         graph_report(_("commit-graph parent list for commit %s terminates early"),
2046                                      oid_to_hex(&cur_oid));
2047
2048                 if (!graph_commit->generation) {
2049                         if (generation_zero == GENERATION_NUMBER_EXISTS)
2050                                 graph_report(_("commit-graph has generation number zero for commit %s, but non-zero elsewhere"),
2051                                              oid_to_hex(&cur_oid));
2052                         generation_zero = GENERATION_ZERO_EXISTS;
2053                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
2054                         graph_report(_("commit-graph has non-zero generation number for commit %s, but zero elsewhere"),
2055                                      oid_to_hex(&cur_oid));
2056
2057                 if (generation_zero == GENERATION_ZERO_EXISTS)
2058                         continue;
2059
2060                 /*
2061                  * If one of our parents has generation GENERATION_NUMBER_MAX, then
2062                  * our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
2063                  * extra logic in the following condition.
2064                  */
2065                 if (max_generation == GENERATION_NUMBER_MAX)
2066                         max_generation--;
2067
2068                 if (graph_commit->generation != max_generation + 1)
2069                         graph_report(_("commit-graph generation for commit %s is %u != %u"),
2070                                      oid_to_hex(&cur_oid),
2071                                      graph_commit->generation,
2072                                      max_generation + 1);
2073
2074                 if (graph_commit->date != odb_commit->date)
2075                         graph_report(_("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime),
2076                                      oid_to_hex(&cur_oid),
2077                                      graph_commit->date,
2078                                      odb_commit->date);
2079         }
2080         stop_progress(&progress);
2081
2082         local_error = verify_commit_graph_error;
2083
2084         if (!(flags & COMMIT_GRAPH_VERIFY_SHALLOW) && g->base_graph)
2085                 local_error |= verify_commit_graph(r, g->base_graph, flags);
2086
2087         return local_error;
2088 }
2089
2090 void free_commit_graph(struct commit_graph *g)
2091 {
2092         if (!g)
2093                 return;
2094         if (g->graph_fd >= 0) {
2095                 munmap((void *)g->data, g->data_len);
2096                 g->data = NULL;
2097                 close(g->graph_fd);
2098         }
2099         free(g->filename);
2100         free(g);
2101 }