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