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
  26 #define GRAPH_DATA_WIDTH (the_hash_algo->rawsz + 16)
  27
  28 #define GRAPH_VERSION_1 0x1
  29 #define GRAPH_VERSION GRAPH_VERSION_1
  30
  31 #define GRAPH_EXTRA_EDGES_NEEDED 0x80000000
  32 #define GRAPH_EDGE_LAST_MASK 0x7fffffff
  33 #define GRAPH_PARENT_NONE 0x70000000
  34
  35 #define GRAPH_LAST_EDGE 0x80000000
  36
  37 #define GRAPH_HEADER_SIZE 8
  38 #define GRAPH_FANOUT_SIZE (4 * 256)
  39 #define GRAPH_CHUNKLOOKUP_WIDTH 12
  40 #define GRAPH_MIN_SIZE (GRAPH_HEADER_SIZE + 4 * GRAPH_CHUNKLOOKUP_WIDTH \
  41                         + GRAPH_FANOUT_SIZE + the_hash_algo->rawsz)
  42
  43 char *get_commit_graph_filename(const char *obj_dir)
  44 {
  45         return xstrfmt("%s/info/commit-graph", obj_dir);
  46 }
  47
  48 static uint8_t oid_version(void)
  49 {
  50         return 1;
  51 }
  52
  53 static struct commit_graph *alloc_commit_graph(void)
  54 {
  55         struct commit_graph *g = xcalloc(1, sizeof(*g));
  56         g->graph_fd = -1;
  57
  58         return g;
  59 }
  60
  61 extern int read_replace_refs;
  62
  63 static int commit_graph_compatible(struct repository *r)
  64 {
  65         if (!r->gitdir)
  66                 return 0;
  67
  68         if (read_replace_refs) {
  69                 prepare_replace_object(r);
  70                 if (hashmap_get_size(&r->objects->replace_map->map))
  71                         return 0;
  72         }
  73
  74         prepare_commit_graft(r);
  75         if (r->parsed_objects && r->parsed_objects->grafts_nr)
  76                 return 0;
  77         if (is_repository_shallow(r))
  78                 return 0;
  79
  80         return 1;
  81 }
  82
  83 int open_commit_graph(const char *graph_file, int *fd, struct stat *st)
  84 {
  85         *fd = git_open(graph_file);
  86         if (*fd < 0)
  87                 return 0;
  88         if (fstat(*fd, st)) {
  89                 close(*fd);
  90                 return 0;
  91         }
  92         return 1;
  93 }
  94
  95 struct commit_graph *load_commit_graph_one_fd_st(int fd, struct stat *st)
  96 {
  97         void *graph_map;
  98         size_t graph_size;
  99         struct commit_graph *ret;
 100
 101         graph_size = xsize_t(st->st_size);
 102
 103         if (graph_size < GRAPH_MIN_SIZE) {
 104                 close(fd);
 105                 error(_("commit-graph file is too small"));
 106                 return NULL;
 107         }
 108         graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
 109         ret = parse_commit_graph(graph_map, fd, graph_size);
 110
 111         if (!ret) {
 112                 munmap(graph_map, graph_size);
 113                 close(fd);
 114         }
 115
 116         return ret;
 117 }
 118
 119 static int verify_commit_graph_lite(struct commit_graph *g)
 120 {
 121         /*
 122          * Basic validation shared between parse_commit_graph()
 123          * which'll be called every time the graph is used, and the
 124          * much more expensive verify_commit_graph() used by
 125          * "commit-graph verify".
 126          *
 127          * There should only be very basic checks here to ensure that
 128          * we don't e.g. segfault in fill_commit_in_graph(), but
 129          * because this is a very hot codepath nothing that e.g. loops
 130          * over g->num_commits, or runs a checksum on the commit-graph
 131          * itself.
 132          */
 133         if (!g->chunk_oid_fanout) {
 134                 error("commit-graph is missing the OID Fanout chunk");
 135                 return 1;
 136         }
 137         if (!g->chunk_oid_lookup) {
 138                 error("commit-graph is missing the OID Lookup chunk");
 139                 return 1;
 140         }
 141         if (!g->chunk_commit_data) {
 142                 error("commit-graph is missing the Commit Data chunk");
 143                 return 1;
 144         }
 145
 146         return 0;
 147 }
 148
 149 struct commit_graph *parse_commit_graph(void *graph_map, int fd,
 150                                         size_t graph_size)
 151 {
 152         const unsigned char *data, *chunk_lookup;
 153         uint32_t i;
 154         struct commit_graph *graph;
 155         uint64_t last_chunk_offset;
 156         uint32_t last_chunk_id;
 157         uint32_t graph_signature;
 158         unsigned char graph_version, hash_version;
 159
 160         if (!graph_map)
 161                 return NULL;
 162
 163         if (graph_size < GRAPH_MIN_SIZE)
 164                 return NULL;
 165
 166         data = (const unsigned char *)graph_map;
 167
 168         graph_signature = get_be32(data);
 169         if (graph_signature != GRAPH_SIGNATURE) {
 170                 error(_("commit-graph signature %X does not match signature %X"),
 171                       graph_signature, GRAPH_SIGNATURE);
 172                 return NULL;
 173         }
 174
 175         graph_version = *(unsigned char*)(data + 4);
 176         if (graph_version != GRAPH_VERSION) {
 177                 error(_("commit-graph version %X does not match version %X"),
 178                       graph_version, GRAPH_VERSION);
 179                 return NULL;
 180         }
 181
 182         hash_version = *(unsigned char*)(data + 5);
 183         if (hash_version != oid_version()) {
 184                 error(_("commit-graph hash version %X does not match version %X"),
 185                       hash_version, oid_version());
 186                 return NULL;
 187         }
 188
 189         graph = alloc_commit_graph();
 190
 191         graph->hash_len = the_hash_algo->rawsz;
 192         graph->num_chunks = *(unsigned char*)(data + 6);
 193         graph->graph_fd = fd;
 194         graph->data = graph_map;
 195         graph->data_len = graph_size;
 196
 197         last_chunk_id = 0;
 198         last_chunk_offset = 8;
 199         chunk_lookup = data + 8;
 200         for (i = 0; i < graph->num_chunks; i++) {
 201                 uint32_t chunk_id;
 202                 uint64_t chunk_offset;
 203                 int chunk_repeated = 0;
 204
 205                 if (data + graph_size - chunk_lookup <
 206                     GRAPH_CHUNKLOOKUP_WIDTH) {
 207                         error(_("commit-graph chunk lookup table entry missing; file may be incomplete"));
 208                         free(graph);
 209                         return NULL;
 210                 }
 211
 212                 chunk_id = get_be32(chunk_lookup + 0);
 213                 chunk_offset = get_be64(chunk_lookup + 4);
 214
 215                 chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
 216
 217                 if (chunk_offset > graph_size - the_hash_algo->rawsz) {
 218                         error(_("commit-graph improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
 219                               (uint32_t)chunk_offset);
 220                         free(graph);
 221                         return NULL;
 222                 }
 223
 224                 switch (chunk_id) {
 225                 case GRAPH_CHUNKID_OIDFANOUT:
 226                         if (graph->chunk_oid_fanout)
 227                                 chunk_repeated = 1;
 228                         else
 229                                 graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
 230                         break;
 231
 232                 case GRAPH_CHUNKID_OIDLOOKUP:
 233                         if (graph->chunk_oid_lookup)
 234                                 chunk_repeated = 1;
 235                         else
 236                                 graph->chunk_oid_lookup = data + chunk_offset;
 237                         break;
 238
 239                 case GRAPH_CHUNKID_DATA:
 240                         if (graph->chunk_commit_data)
 241                                 chunk_repeated = 1;
 242                         else
 243                                 graph->chunk_commit_data = data + chunk_offset;
 244                         break;
 245
 246                 case GRAPH_CHUNKID_EXTRAEDGES:
 247                         if (graph->chunk_extra_edges)
 248                                 chunk_repeated = 1;
 249                         else
 250                                 graph->chunk_extra_edges = data + chunk_offset;
 251                         break;
 252                 }
 253
 254                 if (chunk_repeated) {
 255                         error(_("commit-graph chunk id %08x appears multiple times"), chunk_id);
 256                         free(graph);
 257                         return NULL;
 258                 }
 259
 260                 if (last_chunk_id == GRAPH_CHUNKID_OIDLOOKUP)
 261                 {
 262                         graph->num_commits = (chunk_offset - last_chunk_offset)
 263                                              / graph->hash_len;
 264                 }
 265
 266                 last_chunk_id = chunk_id;
 267                 last_chunk_offset = chunk_offset;
 268         }
 269
 270         if (verify_commit_graph_lite(graph)) {
 271                 free(graph);
 272                 return NULL;
 273         }
 274
 275         return graph;
 276 }
 277
 278 static struct commit_graph *load_commit_graph_one(const char *graph_file)
 279 {
 280
 281         struct stat st;
 282         int fd;
 283         int open_ok = open_commit_graph(graph_file, &fd, &st);
 284
 285         if (!open_ok)
 286                 return NULL;
 287
 288         return load_commit_graph_one_fd_st(fd, &st);
 289 }
 290
 291 static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
 292 {
 293         char *graph_name;
 294
 295         if (r->objects->commit_graph)
 296                 return;
 297
 298         graph_name = get_commit_graph_filename(obj_dir);
 299         r->objects->commit_graph =
 300                 load_commit_graph_one(graph_name);
 301
 302         FREE_AND_NULL(graph_name);
 303 }
 304
 305 /*
 306  * Return 1 if commit_graph is non-NULL, and 0 otherwise.
 307  *
 308  * On the first invocation, this function attemps to load the commit
 309  * graph if the_repository is configured to have one.
 310  */
 311 static int prepare_commit_graph(struct repository *r)
 312 {
 313         struct object_directory *odb;
 314         int config_value;
 315
 316         if (git_env_bool(GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD, 0))
 317                 die("dying as requested by the '%s' variable on commit-graph load!",
 318                     GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD);
 319
 320         if (r->objects->commit_graph_attempted)
 321                 return !!r->objects->commit_graph;
 322         r->objects->commit_graph_attempted = 1;
 323
 324         if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
 325             (repo_config_get_bool(r, "core.commitgraph", &config_value) ||
 326             !config_value))
 327                 /*
 328                  * This repository is not configured to use commit graphs, so
 329                  * do not load one. (But report commit_graph_attempted anyway
 330                  * so that commit graph loading is not attempted again for this
 331                  * repository.)
 332                  */
 333                 return 0;
 334
 335         if (!commit_graph_compatible(r))
 336                 return 0;
 337
 338         prepare_alt_odb(r);
 339         for (odb = r->objects->odb;
 340              !r->objects->commit_graph && odb;
 341              odb = odb->next)
 342                 prepare_commit_graph_one(r, odb->path);
 343         return !!r->objects->commit_graph;
 344 }
 345
 346 int generation_numbers_enabled(struct repository *r)
 347 {
 348         uint32_t first_generation;
 349         struct commit_graph *g;
 350         if (!prepare_commit_graph(r))
 351                return 0;
 352
 353         g = r->objects->commit_graph;
 354
 355         if (!g->num_commits)
 356                 return 0;
 357
 358         first_generation = get_be32(g->chunk_commit_data +
 359                                     g->hash_len + 8) >> 2;
 360
 361         return !!first_generation;
 362 }
 363
 364 void close_commit_graph(struct raw_object_store *o)
 365 {
 366         free_commit_graph(o->commit_graph);
 367         o->commit_graph = NULL;
 368 }
 369
 370 static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
 371 {
 372         return bsearch_hash(oid->hash, g->chunk_oid_fanout,
 373                             g->chunk_oid_lookup, g->hash_len, pos);
 374 }
 375
 376 static struct commit_list **insert_parent_or_die(struct repository *r,
 377                                                  struct commit_graph *g,
 378                                                  uint64_t pos,
 379                                                  struct commit_list **pptr)
 380 {
 381         struct commit *c;
 382         struct object_id oid;
 383
 384         if (pos >= g->num_commits)
 385                 die("invalid parent position %"PRIu64, pos);
 386
 387         hashcpy(oid.hash, g->chunk_oid_lookup + g->hash_len * pos);
 388         c = lookup_commit(r, &oid);
 389         if (!c)
 390                 die(_("could not find commit %s"), oid_to_hex(&oid));
 391         c->graph_pos = pos;
 392         return &commit_list_insert(c, pptr)->next;
 393 }
 394
 395 static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
 396 {
 397         const unsigned char *commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * pos;
 398         item->graph_pos = pos;
 399         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 400 }
 401
 402 static inline void set_commit_tree(struct commit *c, struct tree *t)
 403 {
 404         c->maybe_tree = t;
 405 }
 406
 407 static int fill_commit_in_graph(struct repository *r,
 408                                 struct commit *item,
 409                                 struct commit_graph *g, uint32_t pos)
 410 {
 411         uint32_t edge_value;
 412         uint32_t *parent_data_ptr;
 413         uint64_t date_low, date_high;
 414         struct commit_list **pptr;
 415         const unsigned char *commit_data = g->chunk_commit_data + (g->hash_len + 16) * pos;
 416
 417         item->object.parsed = 1;
 418         item->graph_pos = pos;
 419
 420         set_commit_tree(item, NULL);
 421
 422         date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
 423         date_low = get_be32(commit_data + g->hash_len + 12);
 424         item->date = (timestamp_t)((date_high << 32) | date_low);
 425
 426         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 427
 428         pptr = &item->parents;
 429
 430         edge_value = get_be32(commit_data + g->hash_len);
 431         if (edge_value == GRAPH_PARENT_NONE)
 432                 return 1;
 433         pptr = insert_parent_or_die(r, g, edge_value, pptr);
 434
 435         edge_value = get_be32(commit_data + g->hash_len + 4);
 436         if (edge_value == GRAPH_PARENT_NONE)
 437                 return 1;
 438         if (!(edge_value & GRAPH_EXTRA_EDGES_NEEDED)) {
 439                 pptr = insert_parent_or_die(r, g, edge_value, pptr);
 440                 return 1;
 441         }
 442
 443         parent_data_ptr = (uint32_t*)(g->chunk_extra_edges +
 444                           4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
 445         do {
 446                 edge_value = get_be32(parent_data_ptr);
 447                 pptr = insert_parent_or_die(r, g,
 448                                             edge_value & GRAPH_EDGE_LAST_MASK,
 449                                             pptr);
 450                 parent_data_ptr++;
 451         } while (!(edge_value & GRAPH_LAST_EDGE));
 452
 453         return 1;
 454 }
 455
 456 static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 457 {
 458         if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
 459                 *pos = item->graph_pos;
 460                 return 1;
 461         } else {
 462                 return bsearch_graph(g, &(item->object.oid), pos);
 463         }
 464 }
 465
 466 static int parse_commit_in_graph_one(struct repository *r,
 467                                      struct commit_graph *g,
 468                                      struct commit *item)
 469 {
 470         uint32_t pos;
 471
 472         if (item->object.parsed)
 473                 return 1;
 474
 475         if (find_commit_in_graph(item, g, &pos))
 476                 return fill_commit_in_graph(r, item, g, pos);
 477
 478         return 0;
 479 }
 480
 481 int parse_commit_in_graph(struct repository *r, struct commit *item)
 482 {
 483         if (!prepare_commit_graph(r))
 484                 return 0;
 485         return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
 486 }
 487
 488 void load_commit_graph_info(struct repository *r, struct commit *item)
 489 {
 490         uint32_t pos;
 491         if (!prepare_commit_graph(r))
 492                 return;
 493         if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
 494                 fill_commit_graph_info(item, r->objects->commit_graph, pos);
 495 }
 496
 497 static struct tree *load_tree_for_commit(struct repository *r,
 498                                          struct commit_graph *g,
 499                                          struct commit *c)
 500 {
 501         struct object_id oid;
 502         const unsigned char *commit_data = g->chunk_commit_data +
 503                                            GRAPH_DATA_WIDTH * (c->graph_pos);
 504
 505         hashcpy(oid.hash, commit_data);
 506         set_commit_tree(c, lookup_tree(r, &oid));
 507
 508         return c->maybe_tree;
 509 }
 510
 511 static struct tree *get_commit_tree_in_graph_one(struct repository *r,
 512                                                  struct commit_graph *g,
 513                                                  const struct commit *c)
 514 {
 515         if (c->maybe_tree)
 516                 return c->maybe_tree;
 517         if (c->graph_pos == COMMIT_NOT_FROM_GRAPH)
 518                 BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
 519
 520         return load_tree_for_commit(r, g, (struct commit *)c);
 521 }
 522
 523 struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
 524 {
 525         return get_commit_tree_in_graph_one(r, r->objects->commit_graph, c);
 526 }
 527
 528 struct packed_commit_list {
 529         struct commit **list;
 530         int nr;
 531         int alloc;
 532 };
 533
 534 struct packed_oid_list {
 535         struct object_id *list;
 536         int nr;
 537         int alloc;
 538 };
 539
 540 struct write_commit_graph_context {
 541         struct repository *r;
 542         const char *obj_dir;
 543         char *graph_name;
 544         struct packed_oid_list oids;
 545         struct packed_commit_list commits;
 546         int num_extra_edges;
 547         unsigned long approx_nr_objects;
 548         struct progress *progress;
 549         int progress_done;
 550         uint64_t progress_cnt;
 551         unsigned append:1,
 552                  report_progress:1;
 553 };
 554
 555 static void write_graph_chunk_fanout(struct hashfile *f,
 556                                      struct write_commit_graph_context *ctx)
 557 {
 558         int i, count = 0;
 559         struct commit **list = ctx->commits.list;
 560
 561         /*
 562          * Write the first-level table (the list is sorted,
 563          * but we use a 256-entry lookup to be able to avoid
 564          * having to do eight extra binary search iterations).
 565          */
 566         for (i = 0; i < 256; i++) {
 567                 while (count < ctx->commits.nr) {
 568                         if ((*list)->object.oid.hash[0] != i)
 569                                 break;
 570                         display_progress(ctx->progress, ++ctx->progress_cnt);
 571                         count++;
 572                         list++;
 573                 }
 574
 575                 hashwrite_be32(f, count);
 576         }
 577 }
 578
 579 static void write_graph_chunk_oids(struct hashfile *f, int hash_len,
 580                                    struct write_commit_graph_context *ctx)
 581 {
 582         struct commit **list = ctx->commits.list;
 583         int count;
 584         for (count = 0; count < ctx->commits.nr; count++, list++) {
 585                 display_progress(ctx->progress, ++ctx->progress_cnt);
 586                 hashwrite(f, (*list)->object.oid.hash, (int)hash_len);
 587         }
 588 }
 589
 590 static const unsigned char *commit_to_sha1(size_t index, void *table)
 591 {
 592         struct commit **commits = table;
 593         return commits[index]->object.oid.hash;
 594 }
 595
 596 static void write_graph_chunk_data(struct hashfile *f, int hash_len,
 597                                    struct write_commit_graph_context *ctx)
 598 {
 599         struct commit **list = ctx->commits.list;
 600         struct commit **last = ctx->commits.list + ctx->commits.nr;
 601         uint32_t num_extra_edges = 0;
 602
 603         while (list < last) {
 604                 struct commit_list *parent;
 605                 int edge_value;
 606                 uint32_t packedDate[2];
 607                 display_progress(ctx->progress, ++ctx->progress_cnt);
 608
 609                 parse_commit_no_graph(*list);
 610                 hashwrite(f, get_commit_tree_oid(*list)->hash, hash_len);
 611
 612                 parent = (*list)->parents;
 613
 614                 if (!parent)
 615                         edge_value = GRAPH_PARENT_NONE;
 616                 else {
 617                         edge_value = sha1_pos(parent->item->object.oid.hash,
 618                                               ctx->commits.list,
 619                                               ctx->commits.nr,
 620                                               commit_to_sha1);
 621
 622                         if (edge_value < 0)
 623                                 BUG("missing parent %s for commit %s",
 624                                     oid_to_hex(&parent->item->object.oid),
 625                                     oid_to_hex(&(*list)->object.oid));
 626                 }
 627
 628                 hashwrite_be32(f, edge_value);
 629
 630                 if (parent)
 631                         parent = parent->next;
 632
 633                 if (!parent)
 634                         edge_value = GRAPH_PARENT_NONE;
 635                 else if (parent->next)
 636                         edge_value = GRAPH_EXTRA_EDGES_NEEDED | num_extra_edges;
 637                 else {
 638                         edge_value = sha1_pos(parent->item->object.oid.hash,
 639                                               ctx->commits.list,
 640                                               ctx->commits.nr,
 641                                               commit_to_sha1);
 642                         if (edge_value < 0)
 643                                 BUG("missing parent %s for commit %s",
 644                                     oid_to_hex(&parent->item->object.oid),
 645                                     oid_to_hex(&(*list)->object.oid));
 646                 }
 647
 648                 hashwrite_be32(f, edge_value);
 649
 650                 if (edge_value & GRAPH_EXTRA_EDGES_NEEDED) {
 651                         do {
 652                                 num_extra_edges++;
 653                                 parent = parent->next;
 654                         } while (parent);
 655                 }
 656
 657                 if (sizeof((*list)->date) > 4)
 658                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
 659                 else
 660                         packedDate[0] = 0;
 661
 662                 packedDate[0] |= htonl((*list)->generation << 2);
 663
 664                 packedDate[1] = htonl((*list)->date);
 665                 hashwrite(f, packedDate, 8);
 666
 667                 list++;
 668         }
 669 }
 670
 671 static void write_graph_chunk_extra_edges(struct hashfile *f,
 672                                           struct write_commit_graph_context *ctx)
 673 {
 674         struct commit **list = ctx->commits.list;
 675         struct commit **last = ctx->commits.list + ctx->commits.nr;
 676         struct commit_list *parent;
 677
 678         while (list < last) {
 679                 int num_parents = 0;
 680
 681                 display_progress(ctx->progress, ++ctx->progress_cnt);
 682
 683                 for (parent = (*list)->parents; num_parents < 3 && parent;
 684                      parent = parent->next)
 685                         num_parents++;
 686
 687                 if (num_parents <= 2) {
 688                         list++;
 689                         continue;
 690                 }
 691
 692                 /* Since num_parents > 2, this initializer is safe. */
 693                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
 694                         int edge_value = sha1_pos(parent->item->object.oid.hash,
 695                                                   ctx->commits.list,
 696                                                   ctx->commits.nr,
 697                                                   commit_to_sha1);
 698
 699                         if (edge_value < 0)
 700                                 BUG("missing parent %s for commit %s",
 701                                     oid_to_hex(&parent->item->object.oid),
 702                                     oid_to_hex(&(*list)->object.oid));
 703                         else if (!parent->next)
 704                                 edge_value |= GRAPH_LAST_EDGE;
 705
 706                         hashwrite_be32(f, edge_value);
 707                 }
 708
 709                 list++;
 710         }
 711 }
 712
 713 static int commit_compare(const void *_a, const void *_b)
 714 {
 715         const struct object_id *a = (const struct object_id *)_a;
 716         const struct object_id *b = (const struct object_id *)_b;
 717         return oidcmp(a, b);
 718 }
 719
 720 static int add_packed_commits(const struct object_id *oid,
 721                               struct packed_git *pack,
 722                               uint32_t pos,
 723                               void *data)
 724 {
 725         struct write_commit_graph_context *ctx = (struct write_commit_graph_context*)data;
 726         enum object_type type;
 727         off_t offset = nth_packed_object_offset(pack, pos);
 728         struct object_info oi = OBJECT_INFO_INIT;
 729
 730         if (ctx->progress)
 731                 display_progress(ctx->progress, ++ctx->progress_done);
 732
 733         oi.typep = &type;
 734         if (packed_object_info(ctx->r, pack, offset, &oi) < 0)
 735                 die(_("unable to get type of object %s"), oid_to_hex(oid));
 736
 737         if (type != OBJ_COMMIT)
 738                 return 0;
 739
 740         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
 741         oidcpy(&(ctx->oids.list[ctx->oids.nr]), oid);
 742         ctx->oids.nr++;
 743
 744         return 0;
 745 }
 746
 747 static void add_missing_parents(struct write_commit_graph_context *ctx, struct commit *commit)
 748 {
 749         struct commit_list *parent;
 750         for (parent = commit->parents; parent; parent = parent->next) {
 751                 if (!(parent->item->object.flags & UNINTERESTING)) {
 752                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
 753                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(parent->item->object.oid));
 754                         ctx->oids.nr++;
 755                         parent->item->object.flags |= UNINTERESTING;
 756                 }
 757         }
 758 }
 759
 760 static void close_reachable(struct write_commit_graph_context *ctx)
 761 {
 762         int i;
 763         struct commit *commit;
 764
 765         if (ctx->report_progress)
 766                 ctx->progress = start_delayed_progress(
 767                                         _("Loading known commits in commit graph"),
 768                                         ctx->oids.nr);
 769         for (i = 0; i < ctx->oids.nr; i++) {
 770                 display_progress(ctx->progress, i + 1);
 771                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
 772                 if (commit)
 773                         commit->object.flags |= UNINTERESTING;
 774         }
 775         stop_progress(&ctx->progress);
 776
 777         /*
 778          * As this loop runs, ctx->oids.nr may grow, but not more
 779          * than the number of missing commits in the reachable
 780          * closure.
 781          */
 782         if (ctx->report_progress)
 783                 ctx->progress = start_delayed_progress(
 784                                         _("Expanding reachable commits in commit graph"),
 785                                         ctx->oids.nr);
 786         for (i = 0; i < ctx->oids.nr; i++) {
 787                 display_progress(ctx->progress, i + 1);
 788                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
 789
 790                 if (commit && !parse_commit_no_graph(commit))
 791                         add_missing_parents(ctx, commit);
 792         }
 793         stop_progress(&ctx->progress);
 794
 795         if (ctx->report_progress)
 796                 ctx->progress = start_delayed_progress(
 797                                         _("Clearing commit marks in commit graph"),
 798                                         ctx->oids.nr);
 799         for (i = 0; i < ctx->oids.nr; i++) {
 800                 display_progress(ctx->progress, i + 1);
 801                 commit = lookup_commit(ctx->r, &ctx->oids.list[i]);
 802
 803                 if (commit)
 804                         commit->object.flags &= ~UNINTERESTING;
 805         }
 806         stop_progress(&ctx->progress);
 807 }
 808
 809 static void compute_generation_numbers(struct write_commit_graph_context *ctx)
 810 {
 811         int i;
 812         struct commit_list *list = NULL;
 813
 814         if (ctx->report_progress)
 815                 ctx->progress = start_progress(
 816                                         _("Computing commit graph generation numbers"),
 817                                         ctx->commits.nr);
 818         for (i = 0; i < ctx->commits.nr; i++) {
 819                 display_progress(ctx->progress, i + 1);
 820                 if (ctx->commits.list[i]->generation != GENERATION_NUMBER_INFINITY &&
 821                     ctx->commits.list[i]->generation != GENERATION_NUMBER_ZERO)
 822                         continue;
 823
 824                 commit_list_insert(ctx->commits.list[i], &list);
 825                 while (list) {
 826                         struct commit *current = list->item;
 827                         struct commit_list *parent;
 828                         int all_parents_computed = 1;
 829                         uint32_t max_generation = 0;
 830
 831                         for (parent = current->parents; parent; parent = parent->next) {
 832                                 if (parent->item->generation == GENERATION_NUMBER_INFINITY ||
 833                                     parent->item->generation == GENERATION_NUMBER_ZERO) {
 834                                         all_parents_computed = 0;
 835                                         commit_list_insert(parent->item, &list);
 836                                         break;
 837                                 } else if (parent->item->generation > max_generation) {
 838                                         max_generation = parent->item->generation;
 839                                 }
 840                         }
 841
 842                         if (all_parents_computed) {
 843                                 current->generation = max_generation + 1;
 844                                 pop_commit(&list);
 845
 846                                 if (current->generation > GENERATION_NUMBER_MAX)
 847                                         current->generation = GENERATION_NUMBER_MAX;
 848                         }
 849                 }
 850         }
 851         stop_progress(&ctx->progress);
 852 }
 853
 854 static int add_ref_to_list(const char *refname,
 855                            const struct object_id *oid,
 856                            int flags, void *cb_data)
 857 {
 858         struct string_list *list = (struct string_list *)cb_data;
 859
 860         string_list_append(list, oid_to_hex(oid));
 861         return 0;
 862 }
 863
 864 int write_commit_graph_reachable(const char *obj_dir, unsigned int flags)
 865 {
 866         struct string_list list = STRING_LIST_INIT_DUP;
 867         int result;
 868
 869         for_each_ref(add_ref_to_list, &list);
 870         result = write_commit_graph(obj_dir, NULL, &list,
 871                                     flags);
 872
 873         string_list_clear(&list, 0);
 874         return result;
 875 }
 876
 877 static int fill_oids_from_packs(struct write_commit_graph_context *ctx,
 878                                 struct string_list *pack_indexes)
 879 {
 880         uint32_t i;
 881         struct strbuf progress_title = STRBUF_INIT;
 882         struct strbuf packname = STRBUF_INIT;
 883         int dirlen;
 884
 885         strbuf_addf(&packname, "%s/pack/", ctx->obj_dir);
 886         dirlen = packname.len;
 887         if (ctx->report_progress) {
 888                 strbuf_addf(&progress_title,
 889                             Q_("Finding commits for commit graph in %d pack",
 890                                "Finding commits for commit graph in %d packs",
 891                                pack_indexes->nr),
 892                             pack_indexes->nr);
 893                 ctx->progress = start_delayed_progress(progress_title.buf, 0);
 894                 ctx->progress_done = 0;
 895         }
 896         for (i = 0; i < pack_indexes->nr; i++) {
 897                 struct packed_git *p;
 898                 strbuf_setlen(&packname, dirlen);
 899                 strbuf_addstr(&packname, pack_indexes->items[i].string);
 900                 p = add_packed_git(packname.buf, packname.len, 1);
 901                 if (!p) {
 902                         error(_("error adding pack %s"), packname.buf);
 903                         return -1;
 904                 }
 905                 if (open_pack_index(p)) {
 906                         error(_("error opening index for %s"), packname.buf);
 907                         return -1;
 908                 }
 909                 for_each_object_in_pack(p, add_packed_commits, ctx,
 910                                         FOR_EACH_OBJECT_PACK_ORDER);
 911                 close_pack(p);
 912                 free(p);
 913         }
 914
 915         stop_progress(&ctx->progress);
 916         strbuf_reset(&progress_title);
 917         strbuf_release(&packname);
 918
 919         return 0;
 920 }
 921
 922 static void fill_oids_from_commit_hex(struct write_commit_graph_context *ctx,
 923                                       struct string_list *commit_hex)
 924 {
 925         uint32_t i;
 926         struct strbuf progress_title = STRBUF_INIT;
 927
 928         if (ctx->report_progress) {
 929                 strbuf_addf(&progress_title,
 930                             Q_("Finding commits for commit graph from %d ref",
 931                                "Finding commits for commit graph from %d refs",
 932                                commit_hex->nr),
 933                             commit_hex->nr);
 934                 ctx->progress = start_delayed_progress(
 935                                         progress_title.buf,
 936                                         commit_hex->nr);
 937         }
 938         for (i = 0; i < commit_hex->nr; i++) {
 939                 const char *end;
 940                 struct object_id oid;
 941                 struct commit *result;
 942
 943                 display_progress(ctx->progress, i + 1);
 944                 if (commit_hex->items[i].string &&
 945                     parse_oid_hex(commit_hex->items[i].string, &oid, &end))
 946                         continue;
 947
 948                 result = lookup_commit_reference_gently(ctx->r, &oid, 1);
 949
 950                 if (result) {
 951                         ALLOC_GROW(ctx->oids.list, ctx->oids.nr + 1, ctx->oids.alloc);
 952                         oidcpy(&ctx->oids.list[ctx->oids.nr], &(result->object.oid));
 953                         ctx->oids.nr++;
 954                 }
 955         }
 956         stop_progress(&ctx->progress);
 957         strbuf_release(&progress_title);
 958 }
 959
 960 static void fill_oids_from_all_packs(struct write_commit_graph_context *ctx)
 961 {
 962         if (ctx->report_progress)
 963                 ctx->progress = start_delayed_progress(
 964                         _("Finding commits for commit graph among packed objects"),
 965                         ctx->approx_nr_objects);
 966         for_each_packed_object(add_packed_commits, ctx,
 967                                FOR_EACH_OBJECT_PACK_ORDER);
 968         if (ctx->progress_done < ctx->approx_nr_objects)
 969                 display_progress(ctx->progress, ctx->approx_nr_objects);
 970         stop_progress(&ctx->progress);
 971 }
 972
 973 static uint32_t count_distinct_commits(struct write_commit_graph_context *ctx)
 974 {
 975         uint32_t i, count_distinct = 1;
 976
 977         if (ctx->report_progress)
 978                 ctx->progress = start_delayed_progress(
 979                         _("Counting distinct commits in commit graph"),
 980                         ctx->oids.nr);
 981         display_progress(ctx->progress, 0); /* TODO: Measure QSORT() progress */
 982         QSORT(ctx->oids.list, ctx->oids.nr, commit_compare);
 983
 984         for (i = 1; i < ctx->oids.nr; i++) {
 985                 display_progress(ctx->progress, i + 1);
 986                 if (!oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i]))
 987                         count_distinct++;
 988         }
 989         stop_progress(&ctx->progress);
 990
 991         return count_distinct;
 992 }
 993
 994 static void copy_oids_to_commits(struct write_commit_graph_context *ctx)
 995 {
 996         uint32_t i;
 997         struct commit_list *parent;
 998
 999         ctx->num_extra_edges = 0;
1000         if (ctx->report_progress)
1001                 ctx->progress = start_delayed_progress(
1002                         _("Finding extra edges in commit graph"),
1003                         ctx->oids.nr);
1004         for (i = 0; i < ctx->oids.nr; i++) {
1005                 int num_parents = 0;
1006                 display_progress(ctx->progress, i + 1);
1007                 if (i > 0 && oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i]))
1008                         continue;
1009
1010                 ctx->commits.list[ctx->commits.nr] = lookup_commit(ctx->r, &ctx->oids.list[i]);
1011                 parse_commit_no_graph(ctx->commits.list[ctx->commits.nr]);
1012
1013                 for (parent = ctx->commits.list[ctx->commits.nr]->parents;
1014                      parent; parent = parent->next)
1015                         num_parents++;
1016
1017                 if (num_parents > 2)
1018                         ctx->num_extra_edges += num_parents - 1;
1019
1020                 ctx->commits.nr++;
1021         }
1022         stop_progress(&ctx->progress);
1023 }
1024
1025 static int write_commit_graph_file(struct write_commit_graph_context *ctx)
1026 {
1027         uint32_t i;
1028         struct hashfile *f;
1029         struct lock_file lk = LOCK_INIT;
1030         uint32_t chunk_ids[5];
1031         uint64_t chunk_offsets[5];
1032         const unsigned hashsz = the_hash_algo->rawsz;
1033         struct strbuf progress_title = STRBUF_INIT;
1034         int num_chunks = ctx->num_extra_edges ? 4 : 3;
1035
1036         ctx->graph_name = get_commit_graph_filename(ctx->obj_dir);
1037         if (safe_create_leading_directories(ctx->graph_name)) {
1038                 UNLEAK(ctx->graph_name);
1039                 error(_("unable to create leading directories of %s"),
1040                         ctx->graph_name);
1041                 return -1;
1042         }
1043
1044         hold_lock_file_for_update(&lk, ctx->graph_name, LOCK_DIE_ON_ERROR);
1045         f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
1046
1047         hashwrite_be32(f, GRAPH_SIGNATURE);
1048
1049         hashwrite_u8(f, GRAPH_VERSION);
1050         hashwrite_u8(f, oid_version());
1051         hashwrite_u8(f, num_chunks);
1052         hashwrite_u8(f, 0); /* unused padding byte */
1053
1054         chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
1055         chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
1056         chunk_ids[2] = GRAPH_CHUNKID_DATA;
1057         if (ctx->num_extra_edges)
1058                 chunk_ids[3] = GRAPH_CHUNKID_EXTRAEDGES;
1059         else
1060                 chunk_ids[3] = 0;
1061         chunk_ids[4] = 0;
1062
1063         chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
1064         chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
1065         chunk_offsets[2] = chunk_offsets[1] + hashsz * ctx->commits.nr;
1066         chunk_offsets[3] = chunk_offsets[2] + (hashsz + 16) * ctx->commits.nr;
1067         chunk_offsets[4] = chunk_offsets[3] + 4 * ctx->num_extra_edges;
1068
1069         for (i = 0; i <= num_chunks; i++) {
1070                 uint32_t chunk_write[3];
1071
1072                 chunk_write[0] = htonl(chunk_ids[i]);
1073                 chunk_write[1] = htonl(chunk_offsets[i] >> 32);
1074                 chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
1075                 hashwrite(f, chunk_write, 12);
1076         }
1077
1078         if (ctx->report_progress) {
1079                 strbuf_addf(&progress_title,
1080                             Q_("Writing out commit graph in %d pass",
1081                                "Writing out commit graph in %d passes",
1082                                num_chunks),
1083                             num_chunks);
1084                 ctx->progress = start_delayed_progress(
1085                         progress_title.buf,
1086                         num_chunks * ctx->commits.nr);
1087         }
1088         write_graph_chunk_fanout(f, ctx);
1089         write_graph_chunk_oids(f, hashsz, ctx);
1090         write_graph_chunk_data(f, hashsz, ctx);
1091         if (ctx->num_extra_edges)
1092                 write_graph_chunk_extra_edges(f, ctx);
1093         stop_progress(&ctx->progress);
1094         strbuf_release(&progress_title);
1095
1096         close_commit_graph(ctx->r->objects);
1097         finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
1098         commit_lock_file(&lk);
1099
1100         return 0;
1101 }
1102
1103 int write_commit_graph(const char *obj_dir,
1104                        struct string_list *pack_indexes,
1105                        struct string_list *commit_hex,
1106                        unsigned int flags)
1107 {
1108         struct write_commit_graph_context *ctx;
1109         uint32_t i, count_distinct = 0;
1110         int res = 0;
1111
1112         if (!commit_graph_compatible(the_repository))
1113                 return 0;
1114
1115         ctx = xcalloc(1, sizeof(struct write_commit_graph_context));
1116         ctx->r = the_repository;
1117         ctx->obj_dir = obj_dir;
1118         ctx->append = flags & COMMIT_GRAPH_APPEND ? 1 : 0;
1119         ctx->report_progress = flags & COMMIT_GRAPH_PROGRESS ? 1 : 0;
1120
1121         ctx->approx_nr_objects = approximate_object_count();
1122         ctx->oids.alloc = ctx->approx_nr_objects / 32;
1123
1124         if (ctx->append) {
1125                 prepare_commit_graph_one(ctx->r, ctx->obj_dir);
1126                 if (ctx->r->objects->commit_graph)
1127                         ctx->oids.alloc += ctx->r->objects->commit_graph->num_commits;
1128         }
1129
1130         if (ctx->oids.alloc < 1024)
1131                 ctx->oids.alloc = 1024;
1132         ALLOC_ARRAY(ctx->oids.list, ctx->oids.alloc);
1133
1134         if (ctx->append && ctx->r->objects->commit_graph) {
1135                 struct commit_graph *g = ctx->r->objects->commit_graph;
1136                 for (i = 0; i < g->num_commits; i++) {
1137                         const unsigned char *hash = g->chunk_oid_lookup + g->hash_len * i;
1138                         hashcpy(ctx->oids.list[ctx->oids.nr++].hash, hash);
1139                 }
1140         }
1141
1142         if (pack_indexes) {
1143                 if ((res = fill_oids_from_packs(ctx, pack_indexes)))
1144                         goto cleanup;
1145         }
1146
1147         if (commit_hex)
1148                 fill_oids_from_commit_hex(ctx, commit_hex);
1149
1150         if (!pack_indexes && !commit_hex)
1151                 fill_oids_from_all_packs(ctx);
1152
1153         close_reachable(ctx);
1154
1155         count_distinct = count_distinct_commits(ctx);
1156
1157         if (count_distinct >= GRAPH_EDGE_LAST_MASK) {
1158                 error(_("the commit graph format cannot write %d commits"), count_distinct);
1159                 res = -1;
1160                 goto cleanup;
1161         }
1162
1163         ctx->commits.alloc = count_distinct;
1164         ALLOC_ARRAY(ctx->commits.list, ctx->commits.alloc);
1165
1166         copy_oids_to_commits(ctx);
1167
1168         if (ctx->commits.nr >= GRAPH_EDGE_LAST_MASK) {
1169                 error(_("too many commits to write graph"));
1170                 res = -1;
1171                 goto cleanup;
1172         }
1173
1174         compute_generation_numbers(ctx);
1175
1176         res = write_commit_graph_file(ctx);
1177
1178 cleanup:
1179         free(ctx->graph_name);
1180         free(ctx->commits.list);
1181         free(ctx->oids.list);
1182         free(ctx);
1183
1184         return res;
1185 }
1186
1187 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
1188 static int verify_commit_graph_error;
1189
1190 static void graph_report(const char *fmt, ...)
1191 {
1192         va_list ap;
1193
1194         verify_commit_graph_error = 1;
1195         va_start(ap, fmt);
1196         vfprintf(stderr, fmt, ap);
1197         fprintf(stderr, "\n");
1198         va_end(ap);
1199 }
1200
1201 #define GENERATION_ZERO_EXISTS 1
1202 #define GENERATION_NUMBER_EXISTS 2
1203
1204 int verify_commit_graph(struct repository *r, struct commit_graph *g)
1205 {
1206         uint32_t i, cur_fanout_pos = 0;
1207         struct object_id prev_oid, cur_oid, checksum;
1208         int generation_zero = 0;
1209         struct hashfile *f;
1210         int devnull;
1211         struct progress *progress = NULL;
1212
1213         if (!g) {
1214                 graph_report("no commit-graph file loaded");
1215                 return 1;
1216         }
1217
1218         verify_commit_graph_error = verify_commit_graph_lite(g);
1219         if (verify_commit_graph_error)
1220                 return verify_commit_graph_error;
1221
1222         devnull = open("/dev/null", O_WRONLY);
1223         f = hashfd(devnull, NULL);
1224         hashwrite(f, g->data, g->data_len - g->hash_len);
1225         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
1226         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
1227                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
1228                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
1229         }
1230
1231         for (i = 0; i < g->num_commits; i++) {
1232                 struct commit *graph_commit;
1233
1234                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1235
1236                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
1237                         graph_report(_("commit-graph has incorrect OID order: %s then %s"),
1238                                      oid_to_hex(&prev_oid),
1239                                      oid_to_hex(&cur_oid));
1240
1241                 oidcpy(&prev_oid, &cur_oid);
1242
1243                 while (cur_oid.hash[0] > cur_fanout_pos) {
1244                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1245
1246                         if (i != fanout_value)
1247                                 graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
1248                                              cur_fanout_pos, fanout_value, i);
1249                         cur_fanout_pos++;
1250                 }
1251
1252                 graph_commit = lookup_commit(r, &cur_oid);
1253                 if (!parse_commit_in_graph_one(r, g, graph_commit))
1254                         graph_report(_("failed to parse commit %s from commit-graph"),
1255                                      oid_to_hex(&cur_oid));
1256         }
1257
1258         while (cur_fanout_pos < 256) {
1259                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1260
1261                 if (g->num_commits != fanout_value)
1262                         graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
1263                                      cur_fanout_pos, fanout_value, i);
1264
1265                 cur_fanout_pos++;
1266         }
1267
1268         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
1269                 return verify_commit_graph_error;
1270
1271         progress = start_progress(_("Verifying commits in commit graph"),
1272                                   g->num_commits);
1273         for (i = 0; i < g->num_commits; i++) {
1274                 struct commit *graph_commit, *odb_commit;
1275                 struct commit_list *graph_parents, *odb_parents;
1276                 uint32_t max_generation = 0;
1277
1278                 display_progress(progress, i + 1);
1279                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1280
1281                 graph_commit = lookup_commit(r, &cur_oid);
1282                 odb_commit = (struct commit *)create_object(r, &cur_oid, alloc_commit_node(r));
1283                 if (parse_commit_internal(odb_commit, 0, 0)) {
1284                         graph_report(_("failed to parse commit %s from object database for commit-graph"),
1285                                      oid_to_hex(&cur_oid));
1286                         continue;
1287                 }
1288
1289                 if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
1290                            get_commit_tree_oid(odb_commit)))
1291                         graph_report(_("root tree OID for commit %s in commit-graph is %s != %s"),
1292                                      oid_to_hex(&cur_oid),
1293                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
1294                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
1295
1296                 graph_parents = graph_commit->parents;
1297                 odb_parents = odb_commit->parents;
1298
1299                 while (graph_parents) {
1300                         if (odb_parents == NULL) {
1301                                 graph_report(_("commit-graph parent list for commit %s is too long"),
1302                                              oid_to_hex(&cur_oid));
1303                                 break;
1304                         }
1305
1306                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
1307                                 graph_report(_("commit-graph parent for %s is %s != %s"),
1308                                              oid_to_hex(&cur_oid),
1309                                              oid_to_hex(&graph_parents->item->object.oid),
1310                                              oid_to_hex(&odb_parents->item->object.oid));
1311
1312                         if (graph_parents->item->generation > max_generation)
1313                                 max_generation = graph_parents->item->generation;
1314
1315                         graph_parents = graph_parents->next;
1316                         odb_parents = odb_parents->next;
1317                 }
1318
1319                 if (odb_parents != NULL)
1320                         graph_report(_("commit-graph parent list for commit %s terminates early"),
1321                                      oid_to_hex(&cur_oid));
1322
1323                 if (!graph_commit->generation) {
1324                         if (generation_zero == GENERATION_NUMBER_EXISTS)
1325                                 graph_report(_("commit-graph has generation number zero for commit %s, but non-zero elsewhere"),
1326                                              oid_to_hex(&cur_oid));
1327                         generation_zero = GENERATION_ZERO_EXISTS;
1328                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
1329                         graph_report(_("commit-graph has non-zero generation number for commit %s, but zero elsewhere"),
1330                                      oid_to_hex(&cur_oid));
1331
1332                 if (generation_zero == GENERATION_ZERO_EXISTS)
1333                         continue;
1334
1335                 /*
1336                  * If one of our parents has generation GENERATION_NUMBER_MAX, then
1337                  * our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
1338                  * extra logic in the following condition.
1339                  */
1340                 if (max_generation == GENERATION_NUMBER_MAX)
1341                         max_generation--;
1342
1343                 if (graph_commit->generation != max_generation + 1)
1344                         graph_report(_("commit-graph generation for commit %s is %u != %u"),
1345                                      oid_to_hex(&cur_oid),
1346                                      graph_commit->generation,
1347                                      max_generation + 1);
1348
1349                 if (graph_commit->date != odb_commit->date)
1350                         graph_report(_("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime),
1351                                      oid_to_hex(&cur_oid),
1352                                      graph_commit->date,
1353                                      odb_commit->date);
1354         }
1355         stop_progress(&progress);
1356
1357         return verify_commit_graph_error;
1358 }
1359
1360 void free_commit_graph(struct commit_graph *g)
1361 {
1362         if (!g)
1363                 return;
1364         if (g->graph_fd >= 0) {
1365                 munmap((void *)g->data, g->data_len);
1366                 g->data = NULL;
1367                 close(g->graph_fd);
1368         }
1369         free(g);
1370 }