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 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_EXTRAEDGES:
 213                         if (graph->chunk_extra_edges)
 214                                 chunk_repeated = 1;
 215                         else
 216                                 graph->chunk_extra_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 inline void set_commit_tree(struct commit *c, struct tree *t)
 347 {
 348         c->maybe_tree = t;
 349 }
 350
 351 static int fill_commit_in_graph(struct repository *r,
 352                                 struct commit *item,
 353                                 struct commit_graph *g, uint32_t pos)
 354 {
 355         uint32_t edge_value;
 356         uint32_t *parent_data_ptr;
 357         uint64_t date_low, date_high;
 358         struct commit_list **pptr;
 359         const unsigned char *commit_data = g->chunk_commit_data + (g->hash_len + 16) * pos;
 360
 361         item->object.parsed = 1;
 362         item->graph_pos = pos;
 363
 364         set_commit_tree(item, NULL);
 365
 366         date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
 367         date_low = get_be32(commit_data + g->hash_len + 12);
 368         item->date = (timestamp_t)((date_high << 32) | date_low);
 369
 370         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 371
 372         pptr = &item->parents;
 373
 374         edge_value = get_be32(commit_data + g->hash_len);
 375         if (edge_value == GRAPH_PARENT_NONE)
 376                 return 1;
 377         pptr = insert_parent_or_die(r, g, edge_value, pptr);
 378
 379         edge_value = get_be32(commit_data + g->hash_len + 4);
 380         if (edge_value == GRAPH_PARENT_NONE)
 381                 return 1;
 382         if (!(edge_value & GRAPH_EXTRA_EDGES_NEEDED)) {
 383                 pptr = insert_parent_or_die(r, g, edge_value, pptr);
 384                 return 1;
 385         }
 386
 387         parent_data_ptr = (uint32_t*)(g->chunk_extra_edges +
 388                           4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
 389         do {
 390                 edge_value = get_be32(parent_data_ptr);
 391                 pptr = insert_parent_or_die(r, g,
 392                                             edge_value & GRAPH_EDGE_LAST_MASK,
 393                                             pptr);
 394                 parent_data_ptr++;
 395         } while (!(edge_value & GRAPH_LAST_EDGE));
 396
 397         return 1;
 398 }
 399
 400 static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 401 {
 402         if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
 403                 *pos = item->graph_pos;
 404                 return 1;
 405         } else {
 406                 return bsearch_graph(g, &(item->object.oid), pos);
 407         }
 408 }
 409
 410 static int parse_commit_in_graph_one(struct repository *r,
 411                                      struct commit_graph *g,
 412                                      struct commit *item)
 413 {
 414         uint32_t pos;
 415
 416         if (item->object.parsed)
 417                 return 1;
 418
 419         if (find_commit_in_graph(item, g, &pos))
 420                 return fill_commit_in_graph(r, item, g, pos);
 421
 422         return 0;
 423 }
 424
 425 int parse_commit_in_graph(struct repository *r, struct commit *item)
 426 {
 427         if (!prepare_commit_graph(r))
 428                 return 0;
 429         return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
 430 }
 431
 432 void load_commit_graph_info(struct repository *r, struct commit *item)
 433 {
 434         uint32_t pos;
 435         if (!prepare_commit_graph(r))
 436                 return;
 437         if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
 438                 fill_commit_graph_info(item, r->objects->commit_graph, pos);
 439 }
 440
 441 static struct tree *load_tree_for_commit(struct repository *r,
 442                                          struct commit_graph *g,
 443                                          struct commit *c)
 444 {
 445         struct object_id oid;
 446         const unsigned char *commit_data = g->chunk_commit_data +
 447                                            GRAPH_DATA_WIDTH * (c->graph_pos);
 448
 449         hashcpy(oid.hash, commit_data);
 450         set_commit_tree(c, lookup_tree(r, &oid));
 451
 452         return c->maybe_tree;
 453 }
 454
 455 static struct tree *get_commit_tree_in_graph_one(struct repository *r,
 456                                                  struct commit_graph *g,
 457                                                  const struct commit *c)
 458 {
 459         if (c->maybe_tree)
 460                 return c->maybe_tree;
 461         if (c->graph_pos == COMMIT_NOT_FROM_GRAPH)
 462                 BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
 463
 464         return load_tree_for_commit(r, g, (struct commit *)c);
 465 }
 466
 467 struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
 468 {
 469         return get_commit_tree_in_graph_one(r, r->objects->commit_graph, c);
 470 }
 471
 472 static void write_graph_chunk_fanout(struct hashfile *f,
 473                                      struct commit **commits,
 474                                      int nr_commits,
 475                                      struct progress *progress,
 476                                      uint64_t *progress_cnt)
 477 {
 478         int i, count = 0;
 479         struct commit **list = commits;
 480
 481         /*
 482          * Write the first-level table (the list is sorted,
 483          * but we use a 256-entry lookup to be able to avoid
 484          * having to do eight extra binary search iterations).
 485          */
 486         for (i = 0; i < 256; i++) {
 487                 while (count < nr_commits) {
 488                         if ((*list)->object.oid.hash[0] != i)
 489                                 break;
 490                         display_progress(progress, ++*progress_cnt);
 491                         count++;
 492                         list++;
 493                 }
 494
 495                 hashwrite_be32(f, count);
 496         }
 497 }
 498
 499 static void write_graph_chunk_oids(struct hashfile *f, int hash_len,
 500                                    struct commit **commits, int nr_commits,
 501                                    struct progress *progress,
 502                                    uint64_t *progress_cnt)
 503 {
 504         struct commit **list = commits;
 505         int count;
 506         for (count = 0; count < nr_commits; count++, list++) {
 507                 display_progress(progress, ++*progress_cnt);
 508                 hashwrite(f, (*list)->object.oid.hash, (int)hash_len);
 509         }
 510 }
 511
 512 static const unsigned char *commit_to_sha1(size_t index, void *table)
 513 {
 514         struct commit **commits = table;
 515         return commits[index]->object.oid.hash;
 516 }
 517
 518 static void write_graph_chunk_data(struct hashfile *f, int hash_len,
 519                                    struct commit **commits, int nr_commits,
 520                                    struct progress *progress,
 521                                    uint64_t *progress_cnt)
 522 {
 523         struct commit **list = commits;
 524         struct commit **last = commits + nr_commits;
 525         uint32_t num_extra_edges = 0;
 526
 527         while (list < last) {
 528                 struct commit_list *parent;
 529                 int edge_value;
 530                 uint32_t packedDate[2];
 531                 display_progress(progress, ++*progress_cnt);
 532
 533                 parse_commit(*list);
 534                 hashwrite(f, get_commit_tree_oid(*list)->hash, hash_len);
 535
 536                 parent = (*list)->parents;
 537
 538                 if (!parent)
 539                         edge_value = GRAPH_PARENT_NONE;
 540                 else {
 541                         edge_value = sha1_pos(parent->item->object.oid.hash,
 542                                               commits,
 543                                               nr_commits,
 544                                               commit_to_sha1);
 545
 546                         if (edge_value < 0)
 547                                 BUG("missing parent %s for commit %s",
 548                                     oid_to_hex(&parent->item->object.oid),
 549                                     oid_to_hex(&(*list)->object.oid));
 550                 }
 551
 552                 hashwrite_be32(f, edge_value);
 553
 554                 if (parent)
 555                         parent = parent->next;
 556
 557                 if (!parent)
 558                         edge_value = GRAPH_PARENT_NONE;
 559                 else if (parent->next)
 560                         edge_value = GRAPH_EXTRA_EDGES_NEEDED | num_extra_edges;
 561                 else {
 562                         edge_value = sha1_pos(parent->item->object.oid.hash,
 563                                               commits,
 564                                               nr_commits,
 565                                               commit_to_sha1);
 566                         if (edge_value < 0)
 567                                 BUG("missing parent %s for commit %s",
 568                                     oid_to_hex(&parent->item->object.oid),
 569                                     oid_to_hex(&(*list)->object.oid));
 570                 }
 571
 572                 hashwrite_be32(f, edge_value);
 573
 574                 if (edge_value & GRAPH_EXTRA_EDGES_NEEDED) {
 575                         do {
 576                                 num_extra_edges++;
 577                                 parent = parent->next;
 578                         } while (parent);
 579                 }
 580
 581                 if (sizeof((*list)->date) > 4)
 582                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
 583                 else
 584                         packedDate[0] = 0;
 585
 586                 packedDate[0] |= htonl((*list)->generation << 2);
 587
 588                 packedDate[1] = htonl((*list)->date);
 589                 hashwrite(f, packedDate, 8);
 590
 591                 list++;
 592         }
 593 }
 594
 595 static void write_graph_chunk_extra_edges(struct hashfile *f,
 596                                           struct commit **commits,
 597                                           int nr_commits,
 598                                           struct progress *progress,
 599                                           uint64_t *progress_cnt)
 600 {
 601         struct commit **list = commits;
 602         struct commit **last = commits + nr_commits;
 603         struct commit_list *parent;
 604
 605         while (list < last) {
 606                 int num_parents = 0;
 607
 608                 display_progress(progress, ++*progress_cnt);
 609
 610                 for (parent = (*list)->parents; num_parents < 3 && parent;
 611                      parent = parent->next)
 612                         num_parents++;
 613
 614                 if (num_parents <= 2) {
 615                         list++;
 616                         continue;
 617                 }
 618
 619                 /* Since num_parents > 2, this initializer is safe. */
 620                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
 621                         int edge_value = sha1_pos(parent->item->object.oid.hash,
 622                                                   commits,
 623                                                   nr_commits,
 624                                                   commit_to_sha1);
 625
 626                         if (edge_value < 0)
 627                                 BUG("missing parent %s for commit %s",
 628                                     oid_to_hex(&parent->item->object.oid),
 629                                     oid_to_hex(&(*list)->object.oid));
 630                         else if (!parent->next)
 631                                 edge_value |= GRAPH_LAST_EDGE;
 632
 633                         hashwrite_be32(f, edge_value);
 634                 }
 635
 636                 list++;
 637         }
 638 }
 639
 640 static int commit_compare(const void *_a, const void *_b)
 641 {
 642         const struct object_id *a = (const struct object_id *)_a;
 643         const struct object_id *b = (const struct object_id *)_b;
 644         return oidcmp(a, b);
 645 }
 646
 647 struct packed_commit_list {
 648         struct commit **list;
 649         int nr;
 650         int alloc;
 651 };
 652
 653 struct packed_oid_list {
 654         struct object_id *list;
 655         int nr;
 656         int alloc;
 657         struct progress *progress;
 658         int progress_done;
 659 };
 660
 661 static int add_packed_commits(const struct object_id *oid,
 662                               struct packed_git *pack,
 663                               uint32_t pos,
 664                               void *data)
 665 {
 666         struct packed_oid_list *list = (struct packed_oid_list*)data;
 667         enum object_type type;
 668         off_t offset = nth_packed_object_offset(pack, pos);
 669         struct object_info oi = OBJECT_INFO_INIT;
 670
 671         if (list->progress)
 672                 display_progress(list->progress, ++list->progress_done);
 673
 674         oi.typep = &type;
 675         if (packed_object_info(the_repository, pack, offset, &oi) < 0)
 676                 die(_("unable to get type of object %s"), oid_to_hex(oid));
 677
 678         if (type != OBJ_COMMIT)
 679                 return 0;
 680
 681         ALLOC_GROW(list->list, list->nr + 1, list->alloc);
 682         oidcpy(&(list->list[list->nr]), oid);
 683         list->nr++;
 684
 685         return 0;
 686 }
 687
 688 static void add_missing_parents(struct packed_oid_list *oids, struct commit *commit)
 689 {
 690         struct commit_list *parent;
 691         for (parent = commit->parents; parent; parent = parent->next) {
 692                 if (!(parent->item->object.flags & UNINTERESTING)) {
 693                         ALLOC_GROW(oids->list, oids->nr + 1, oids->alloc);
 694                         oidcpy(&oids->list[oids->nr], &(parent->item->object.oid));
 695                         oids->nr++;
 696                         parent->item->object.flags |= UNINTERESTING;
 697                 }
 698         }
 699 }
 700
 701 static void close_reachable(struct packed_oid_list *oids, int report_progress)
 702 {
 703         int i;
 704         struct commit *commit;
 705         struct progress *progress = NULL;
 706
 707         if (report_progress)
 708                 progress = start_delayed_progress(
 709                         _("Loading known commits in commit graph"), oids->nr);
 710         for (i = 0; i < oids->nr; i++) {
 711                 display_progress(progress, i + 1);
 712                 commit = lookup_commit(the_repository, &oids->list[i]);
 713                 if (commit)
 714                         commit->object.flags |= UNINTERESTING;
 715         }
 716         stop_progress(&progress);
 717
 718         /*
 719          * As this loop runs, oids->nr may grow, but not more
 720          * than the number of missing commits in the reachable
 721          * closure.
 722          */
 723         if (report_progress)
 724                 progress = start_delayed_progress(
 725                         _("Expanding reachable commits in commit graph"), oids->nr);
 726         for (i = 0; i < oids->nr; i++) {
 727                 display_progress(progress, i + 1);
 728                 commit = lookup_commit(the_repository, &oids->list[i]);
 729
 730                 if (commit && !parse_commit(commit))
 731                         add_missing_parents(oids, commit);
 732         }
 733         stop_progress(&progress);
 734
 735         if (report_progress)
 736                 progress = start_delayed_progress(
 737                         _("Clearing commit marks in commit graph"), oids->nr);
 738         for (i = 0; i < oids->nr; i++) {
 739                 display_progress(progress, i + 1);
 740                 commit = lookup_commit(the_repository, &oids->list[i]);
 741
 742                 if (commit)
 743                         commit->object.flags &= ~UNINTERESTING;
 744         }
 745         stop_progress(&progress);
 746 }
 747
 748 static void compute_generation_numbers(struct packed_commit_list* commits,
 749                                        int report_progress)
 750 {
 751         int i;
 752         struct commit_list *list = NULL;
 753         struct progress *progress = NULL;
 754
 755         if (report_progress)
 756                 progress = start_progress(
 757                         _("Computing commit graph generation numbers"),
 758                         commits->nr);
 759         for (i = 0; i < commits->nr; i++) {
 760                 display_progress(progress, i + 1);
 761                 if (commits->list[i]->generation != GENERATION_NUMBER_INFINITY &&
 762                     commits->list[i]->generation != GENERATION_NUMBER_ZERO)
 763                         continue;
 764
 765                 commit_list_insert(commits->list[i], &list);
 766                 while (list) {
 767                         struct commit *current = list->item;
 768                         struct commit_list *parent;
 769                         int all_parents_computed = 1;
 770                         uint32_t max_generation = 0;
 771
 772                         for (parent = current->parents; parent; parent = parent->next) {
 773                                 if (parent->item->generation == GENERATION_NUMBER_INFINITY ||
 774                                     parent->item->generation == GENERATION_NUMBER_ZERO) {
 775                                         all_parents_computed = 0;
 776                                         commit_list_insert(parent->item, &list);
 777                                         break;
 778                                 } else if (parent->item->generation > max_generation) {
 779                                         max_generation = parent->item->generation;
 780                                 }
 781                         }
 782
 783                         if (all_parents_computed) {
 784                                 current->generation = max_generation + 1;
 785                                 pop_commit(&list);
 786
 787                                 if (current->generation > GENERATION_NUMBER_MAX)
 788                                         current->generation = GENERATION_NUMBER_MAX;
 789                         }
 790                 }
 791         }
 792         stop_progress(&progress);
 793 }
 794
 795 static int add_ref_to_list(const char *refname,
 796                            const struct object_id *oid,
 797                            int flags, void *cb_data)
 798 {
 799         struct string_list *list = (struct string_list *)cb_data;
 800
 801         string_list_append(list, oid_to_hex(oid));
 802         return 0;
 803 }
 804
 805 void write_commit_graph_reachable(const char *obj_dir, int append,
 806                                   int report_progress)
 807 {
 808         struct string_list list = STRING_LIST_INIT_DUP;
 809
 810         for_each_ref(add_ref_to_list, &list);
 811         write_commit_graph(obj_dir, NULL, &list, append, report_progress);
 812
 813         string_list_clear(&list, 0);
 814 }
 815
 816 void write_commit_graph(const char *obj_dir,
 817                         struct string_list *pack_indexes,
 818                         struct string_list *commit_hex,
 819                         int append, int report_progress)
 820 {
 821         struct packed_oid_list oids;
 822         struct packed_commit_list commits;
 823         struct hashfile *f;
 824         uint32_t i, count_distinct = 0;
 825         char *graph_name;
 826         struct lock_file lk = LOCK_INIT;
 827         uint32_t chunk_ids[5];
 828         uint64_t chunk_offsets[5];
 829         int num_chunks;
 830         int num_extra_edges;
 831         struct commit_list *parent;
 832         struct progress *progress = NULL;
 833         const unsigned hashsz = the_hash_algo->rawsz;
 834         uint64_t progress_cnt = 0;
 835         struct strbuf progress_title = STRBUF_INIT;
 836         unsigned long approx_nr_objects;
 837
 838         if (!commit_graph_compatible(the_repository))
 839                 return;
 840
 841         oids.nr = 0;
 842         approx_nr_objects = approximate_object_count();
 843         oids.alloc = approx_nr_objects / 32;
 844         oids.progress = NULL;
 845         oids.progress_done = 0;
 846
 847         if (append) {
 848                 prepare_commit_graph_one(the_repository, obj_dir);
 849                 if (the_repository->objects->commit_graph)
 850                         oids.alloc += the_repository->objects->commit_graph->num_commits;
 851         }
 852
 853         if (oids.alloc < 1024)
 854                 oids.alloc = 1024;
 855         ALLOC_ARRAY(oids.list, oids.alloc);
 856
 857         if (append && the_repository->objects->commit_graph) {
 858                 struct commit_graph *commit_graph =
 859                         the_repository->objects->commit_graph;
 860                 for (i = 0; i < commit_graph->num_commits; i++) {
 861                         const unsigned char *hash = commit_graph->chunk_oid_lookup +
 862                                 commit_graph->hash_len * i;
 863                         hashcpy(oids.list[oids.nr++].hash, hash);
 864                 }
 865         }
 866
 867         if (pack_indexes) {
 868                 struct strbuf packname = STRBUF_INIT;
 869                 int dirlen;
 870                 strbuf_addf(&packname, "%s/pack/", obj_dir);
 871                 dirlen = packname.len;
 872                 if (report_progress) {
 873                         strbuf_addf(&progress_title,
 874                                     Q_("Finding commits for commit graph in %d pack",
 875                                        "Finding commits for commit graph in %d packs",
 876                                        pack_indexes->nr),
 877                                     pack_indexes->nr);
 878                         oids.progress = start_delayed_progress(progress_title.buf, 0);
 879                         oids.progress_done = 0;
 880                 }
 881                 for (i = 0; i < pack_indexes->nr; i++) {
 882                         struct packed_git *p;
 883                         strbuf_setlen(&packname, dirlen);
 884                         strbuf_addstr(&packname, pack_indexes->items[i].string);
 885                         p = add_packed_git(packname.buf, packname.len, 1);
 886                         if (!p)
 887                                 die(_("error adding pack %s"), packname.buf);
 888                         if (open_pack_index(p))
 889                                 die(_("error opening index for %s"), packname.buf);
 890                         for_each_object_in_pack(p, add_packed_commits, &oids,
 891                                                 FOR_EACH_OBJECT_PACK_ORDER);
 892                         close_pack(p);
 893                         free(p);
 894                 }
 895                 stop_progress(&oids.progress);
 896                 strbuf_reset(&progress_title);
 897                 strbuf_release(&packname);
 898         }
 899
 900         if (commit_hex) {
 901                 if (report_progress) {
 902                         strbuf_addf(&progress_title,
 903                                     Q_("Finding commits for commit graph from %d ref",
 904                                        "Finding commits for commit graph from %d refs",
 905                                        commit_hex->nr),
 906                                     commit_hex->nr);
 907                         progress = start_delayed_progress(progress_title.buf,
 908                                                           commit_hex->nr);
 909                 }
 910                 for (i = 0; i < commit_hex->nr; i++) {
 911                         const char *end;
 912                         struct object_id oid;
 913                         struct commit *result;
 914
 915                         display_progress(progress, i + 1);
 916                         if (commit_hex->items[i].string &&
 917                             parse_oid_hex(commit_hex->items[i].string, &oid, &end))
 918                                 continue;
 919
 920                         result = lookup_commit_reference_gently(the_repository, &oid, 1);
 921
 922                         if (result) {
 923                                 ALLOC_GROW(oids.list, oids.nr + 1, oids.alloc);
 924                                 oidcpy(&oids.list[oids.nr], &(result->object.oid));
 925                                 oids.nr++;
 926                         }
 927                 }
 928                 stop_progress(&progress);
 929                 strbuf_reset(&progress_title);
 930         }
 931
 932         if (!pack_indexes && !commit_hex) {
 933                 if (report_progress)
 934                         oids.progress = start_delayed_progress(
 935                                 _("Finding commits for commit graph among packed objects"),
 936                                 approx_nr_objects);
 937                 for_each_packed_object(add_packed_commits, &oids,
 938                                        FOR_EACH_OBJECT_PACK_ORDER);
 939                 if (oids.progress_done < approx_nr_objects)
 940                         display_progress(oids.progress, approx_nr_objects);
 941                 stop_progress(&oids.progress);
 942         }
 943
 944         close_reachable(&oids, report_progress);
 945
 946         if (report_progress)
 947                 progress = start_delayed_progress(
 948                         _("Counting distinct commits in commit graph"),
 949                         oids.nr);
 950         display_progress(progress, 0); /* TODO: Measure QSORT() progress */
 951         QSORT(oids.list, oids.nr, commit_compare);
 952         count_distinct = 1;
 953         for (i = 1; i < oids.nr; i++) {
 954                 display_progress(progress, i + 1);
 955                 if (!oideq(&oids.list[i - 1], &oids.list[i]))
 956                         count_distinct++;
 957         }
 958         stop_progress(&progress);
 959
 960         if (count_distinct >= GRAPH_EDGE_LAST_MASK)
 961                 die(_("the commit graph format cannot write %d commits"), count_distinct);
 962
 963         commits.nr = 0;
 964         commits.alloc = count_distinct;
 965         ALLOC_ARRAY(commits.list, commits.alloc);
 966
 967         num_extra_edges = 0;
 968         if (report_progress)
 969                 progress = start_delayed_progress(
 970                         _("Finding extra edges in commit graph"),
 971                         oids.nr);
 972         for (i = 0; i < oids.nr; i++) {
 973                 int num_parents = 0;
 974                 display_progress(progress, i + 1);
 975                 if (i > 0 && oideq(&oids.list[i - 1], &oids.list[i]))
 976                         continue;
 977
 978                 commits.list[commits.nr] = lookup_commit(the_repository, &oids.list[i]);
 979                 parse_commit(commits.list[commits.nr]);
 980
 981                 for (parent = commits.list[commits.nr]->parents;
 982                      parent; parent = parent->next)
 983                         num_parents++;
 984
 985                 if (num_parents > 2)
 986                         num_extra_edges += num_parents - 1;
 987
 988                 commits.nr++;
 989         }
 990         num_chunks = num_extra_edges ? 4 : 3;
 991         stop_progress(&progress);
 992
 993         if (commits.nr >= GRAPH_EDGE_LAST_MASK)
 994                 die(_("too many commits to write graph"));
 995
 996         compute_generation_numbers(&commits, report_progress);
 997
 998         graph_name = get_commit_graph_filename(obj_dir);
 999         if (safe_create_leading_directories(graph_name)) {
1000                 UNLEAK(graph_name);
1001                 die_errno(_("unable to create leading directories of %s"),
1002                           graph_name);
1003         }
1004
1005         hold_lock_file_for_update(&lk, graph_name, LOCK_DIE_ON_ERROR);
1006         f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
1007
1008         hashwrite_be32(f, GRAPH_SIGNATURE);
1009
1010         hashwrite_u8(f, GRAPH_VERSION);
1011         hashwrite_u8(f, oid_version());
1012         hashwrite_u8(f, num_chunks);
1013         hashwrite_u8(f, 0); /* unused padding byte */
1014
1015         chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
1016         chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
1017         chunk_ids[2] = GRAPH_CHUNKID_DATA;
1018         if (num_extra_edges)
1019                 chunk_ids[3] = GRAPH_CHUNKID_EXTRAEDGES;
1020         else
1021                 chunk_ids[3] = 0;
1022         chunk_ids[4] = 0;
1023
1024         chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
1025         chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
1026         chunk_offsets[2] = chunk_offsets[1] + hashsz * commits.nr;
1027         chunk_offsets[3] = chunk_offsets[2] + (hashsz + 16) * commits.nr;
1028         chunk_offsets[4] = chunk_offsets[3] + 4 * num_extra_edges;
1029
1030         for (i = 0; i <= num_chunks; i++) {
1031                 uint32_t chunk_write[3];
1032
1033                 chunk_write[0] = htonl(chunk_ids[i]);
1034                 chunk_write[1] = htonl(chunk_offsets[i] >> 32);
1035                 chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
1036                 hashwrite(f, chunk_write, 12);
1037         }
1038
1039         if (report_progress) {
1040                 strbuf_addf(&progress_title,
1041                             Q_("Writing out commit graph in %d pass",
1042                                "Writing out commit graph in %d passes",
1043                                num_chunks),
1044                             num_chunks);
1045                 progress = start_delayed_progress(
1046                         progress_title.buf,
1047                         num_chunks * commits.nr);
1048         }
1049         write_graph_chunk_fanout(f, commits.list, commits.nr, progress, &progress_cnt);
1050         write_graph_chunk_oids(f, hashsz, commits.list, commits.nr, progress, &progress_cnt);
1051         write_graph_chunk_data(f, hashsz, commits.list, commits.nr, progress, &progress_cnt);
1052         if (num_extra_edges)
1053                 write_graph_chunk_extra_edges(f, commits.list, commits.nr, progress, &progress_cnt);
1054         stop_progress(&progress);
1055         strbuf_release(&progress_title);
1056
1057         close_commit_graph(the_repository);
1058         finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
1059         commit_lock_file(&lk);
1060
1061         free(graph_name);
1062         free(commits.list);
1063         free(oids.list);
1064 }
1065
1066 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
1067 static int verify_commit_graph_error;
1068
1069 static void graph_report(const char *fmt, ...)
1070 {
1071         va_list ap;
1072
1073         verify_commit_graph_error = 1;
1074         va_start(ap, fmt);
1075         vfprintf(stderr, fmt, ap);
1076         fprintf(stderr, "\n");
1077         va_end(ap);
1078 }
1079
1080 #define GENERATION_ZERO_EXISTS 1
1081 #define GENERATION_NUMBER_EXISTS 2
1082
1083 int verify_commit_graph(struct repository *r, struct commit_graph *g)
1084 {
1085         uint32_t i, cur_fanout_pos = 0;
1086         struct object_id prev_oid, cur_oid, checksum;
1087         int generation_zero = 0;
1088         struct hashfile *f;
1089         int devnull;
1090         struct progress *progress = NULL;
1091
1092         if (!g) {
1093                 graph_report("no commit-graph file loaded");
1094                 return 1;
1095         }
1096
1097         verify_commit_graph_error = 0;
1098
1099         if (!g->chunk_oid_fanout)
1100                 graph_report("commit-graph is missing the OID Fanout chunk");
1101         if (!g->chunk_oid_lookup)
1102                 graph_report("commit-graph is missing the OID Lookup chunk");
1103         if (!g->chunk_commit_data)
1104                 graph_report("commit-graph is missing the Commit Data chunk");
1105
1106         if (verify_commit_graph_error)
1107                 return verify_commit_graph_error;
1108
1109         devnull = open("/dev/null", O_WRONLY);
1110         f = hashfd(devnull, NULL);
1111         hashwrite(f, g->data, g->data_len - g->hash_len);
1112         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
1113         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
1114                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
1115                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
1116         }
1117
1118         for (i = 0; i < g->num_commits; i++) {
1119                 struct commit *graph_commit;
1120
1121                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1122
1123                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
1124                         graph_report("commit-graph has incorrect OID order: %s then %s",
1125                                      oid_to_hex(&prev_oid),
1126                                      oid_to_hex(&cur_oid));
1127
1128                 oidcpy(&prev_oid, &cur_oid);
1129
1130                 while (cur_oid.hash[0] > cur_fanout_pos) {
1131                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1132
1133                         if (i != fanout_value)
1134                                 graph_report("commit-graph has incorrect fanout value: fanout[%d] = %u != %u",
1135                                              cur_fanout_pos, fanout_value, i);
1136                         cur_fanout_pos++;
1137                 }
1138
1139                 graph_commit = lookup_commit(r, &cur_oid);
1140                 if (!parse_commit_in_graph_one(r, g, graph_commit))
1141                         graph_report("failed to parse %s from commit-graph",
1142                                      oid_to_hex(&cur_oid));
1143         }
1144
1145         while (cur_fanout_pos < 256) {
1146                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1147
1148                 if (g->num_commits != fanout_value)
1149                         graph_report("commit-graph has incorrect fanout value: fanout[%d] = %u != %u",
1150                                      cur_fanout_pos, fanout_value, i);
1151
1152                 cur_fanout_pos++;
1153         }
1154
1155         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
1156                 return verify_commit_graph_error;
1157
1158         progress = start_progress(_("Verifying commits in commit graph"),
1159                                   g->num_commits);
1160         for (i = 0; i < g->num_commits; i++) {
1161                 struct commit *graph_commit, *odb_commit;
1162                 struct commit_list *graph_parents, *odb_parents;
1163                 uint32_t max_generation = 0;
1164
1165                 display_progress(progress, i + 1);
1166                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1167
1168                 graph_commit = lookup_commit(r, &cur_oid);
1169                 odb_commit = (struct commit *)create_object(r, cur_oid.hash, alloc_commit_node(r));
1170                 if (parse_commit_internal(odb_commit, 0, 0)) {
1171                         graph_report("failed to parse %s from object database",
1172                                      oid_to_hex(&cur_oid));
1173                         continue;
1174                 }
1175
1176                 if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
1177                            get_commit_tree_oid(odb_commit)))
1178                         graph_report("root tree OID for commit %s in commit-graph is %s != %s",
1179                                      oid_to_hex(&cur_oid),
1180                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
1181                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
1182
1183                 graph_parents = graph_commit->parents;
1184                 odb_parents = odb_commit->parents;
1185
1186                 while (graph_parents) {
1187                         if (odb_parents == NULL) {
1188                                 graph_report("commit-graph parent list for commit %s is too long",
1189                                              oid_to_hex(&cur_oid));
1190                                 break;
1191                         }
1192
1193                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
1194                                 graph_report("commit-graph parent for %s is %s != %s",
1195                                              oid_to_hex(&cur_oid),
1196                                              oid_to_hex(&graph_parents->item->object.oid),
1197                                              oid_to_hex(&odb_parents->item->object.oid));
1198
1199                         if (graph_parents->item->generation > max_generation)
1200                                 max_generation = graph_parents->item->generation;
1201
1202                         graph_parents = graph_parents->next;
1203                         odb_parents = odb_parents->next;
1204                 }
1205
1206                 if (odb_parents != NULL)
1207                         graph_report("commit-graph parent list for commit %s terminates early",
1208                                      oid_to_hex(&cur_oid));
1209
1210                 if (!graph_commit->generation) {
1211                         if (generation_zero == GENERATION_NUMBER_EXISTS)
1212                                 graph_report("commit-graph has generation number zero for commit %s, but non-zero elsewhere",
1213                                              oid_to_hex(&cur_oid));
1214                         generation_zero = GENERATION_ZERO_EXISTS;
1215                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
1216                         graph_report("commit-graph has non-zero generation number for commit %s, but zero elsewhere",
1217                                      oid_to_hex(&cur_oid));
1218
1219                 if (generation_zero == GENERATION_ZERO_EXISTS)
1220                         continue;
1221
1222                 /*
1223                  * If one of our parents has generation GENERATION_NUMBER_MAX, then
1224                  * our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
1225                  * extra logic in the following condition.
1226                  */
1227                 if (max_generation == GENERATION_NUMBER_MAX)
1228                         max_generation--;
1229
1230                 if (graph_commit->generation != max_generation + 1)
1231                         graph_report("commit-graph generation for commit %s is %u != %u",
1232                                      oid_to_hex(&cur_oid),
1233                                      graph_commit->generation,
1234                                      max_generation + 1);
1235
1236                 if (graph_commit->date != odb_commit->date)
1237                         graph_report("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime,
1238                                      oid_to_hex(&cur_oid),
1239                                      graph_commit->date,
1240                                      odb_commit->date);
1241         }
1242         stop_progress(&progress);
1243
1244         return verify_commit_graph_error;
1245 }
1246
1247 void free_commit_graph(struct commit_graph *g)
1248 {
1249         if (!g)
1250                 return;
1251         if (g->graph_fd >= 0) {
1252                 munmap((void *)g->data, g->data_len);
1253                 g->data = NULL;
1254                 close(g->graph_fd);
1255         }
1256         free(g);
1257 }