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