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

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "dir.h"
   4 #include "git-compat-util.h"
   5 #include "lockfile.h"
   6 #include "pack.h"
   7 #include "packfile.h"
   8 #include "commit.h"
   9 #include "object.h"
  10 #include "refs.h"
  11 #include "revision.h"
  12 #include "sha1-lookup.h"
  13 #include "commit-graph.h"
  14 #include "object-store.h"
  15 #include "alloc.h"
  16 #include "hashmap.h"
  17 #include "replace-object.h"
  18 #include "progress.h"
  19
  20 #define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */
  21 #define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
  22 #define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
  23 #define GRAPH_CHUNKID_DATA 0x43444154 /* "CDAT" */
  24 #define GRAPH_CHUNKID_LARGEEDGES 0x45444745 /* "EDGE" */
  25
  26 #define GRAPH_DATA_WIDTH 36
  27
  28 #define GRAPH_VERSION_1 0x1
  29 #define GRAPH_VERSION GRAPH_VERSION_1
  30
  31 #define GRAPH_OID_VERSION_SHA1 1
  32 #define GRAPH_OID_LEN_SHA1 GIT_SHA1_RAWSZ
  33 #define GRAPH_OID_VERSION GRAPH_OID_VERSION_SHA1
  34 #define GRAPH_OID_LEN GRAPH_OID_LEN_SHA1
  35
  36 #define GRAPH_OCTOPUS_EDGES_NEEDED 0x80000000
  37 #define GRAPH_PARENT_MISSING 0x7fffffff
  38 #define GRAPH_EDGE_LAST_MASK 0x7fffffff
  39 #define GRAPH_PARENT_NONE 0x70000000
  40
  41 #define GRAPH_LAST_EDGE 0x80000000
  42
  43 #define GRAPH_HEADER_SIZE 8
  44 #define GRAPH_FANOUT_SIZE (4 * 256)
  45 #define GRAPH_CHUNKLOOKUP_WIDTH 12
  46 #define GRAPH_MIN_SIZE (GRAPH_HEADER_SIZE + 4 * GRAPH_CHUNKLOOKUP_WIDTH \
  47                         + GRAPH_FANOUT_SIZE + GRAPH_OID_LEN)
  48
  49 char *get_commit_graph_filename(const char *obj_dir)
  50 {
  51         return xstrfmt("%s/info/commit-graph", obj_dir);
  52 }
  53
  54 static struct commit_graph *alloc_commit_graph(void)
  55 {
  56         struct commit_graph *g = xcalloc(1, sizeof(*g));
  57         g->graph_fd = -1;
  58
  59         return g;
  60 }
  61
  62 extern int read_replace_refs;
  63
  64 static int commit_graph_compatible(struct repository *r)
  65 {
  66         if (!r->gitdir)
  67                 return 0;
  68
  69         if (read_replace_refs) {
  70                 prepare_replace_object(r);
  71                 if (hashmap_get_size(&r->objects->replace_map->map))
  72                         return 0;
  73         }
  74
  75         prepare_commit_graft(r);
  76         if (r->parsed_objects && r->parsed_objects->grafts_nr)
  77                 return 0;
  78         if (is_repository_shallow(r))
  79                 return 0;
  80
  81         return 1;
  82 }
  83
  84 struct commit_graph *load_commit_graph_one(const char *graph_file)
  85 {
  86         void *graph_map;
  87         const unsigned char *data, *chunk_lookup;
  88         size_t graph_size;
  89         struct stat st;
  90         uint32_t i;
  91         struct commit_graph *graph;
  92         int fd = git_open(graph_file);
  93         uint64_t last_chunk_offset;
  94         uint32_t last_chunk_id;
  95         uint32_t graph_signature;
  96         unsigned char graph_version, hash_version;
  97
  98         if (fd < 0)
  99                 return NULL;
 100         if (fstat(fd, &st)) {
 101                 close(fd);
 102                 return NULL;
 103         }
 104         graph_size = xsize_t(st.st_size);
 105
 106         if (graph_size < GRAPH_MIN_SIZE) {
 107                 close(fd);
 108                 die(_("graph file %s is too small"), graph_file);
 109         }
 110         graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
 111         data = (const unsigned char *)graph_map;
 112
 113         graph_signature = get_be32(data);
 114         if (graph_signature != GRAPH_SIGNATURE) {
 115                 error(_("graph signature %X does not match signature %X"),
 116                       graph_signature, GRAPH_SIGNATURE);
 117                 goto cleanup_fail;
 118         }
 119
 120         graph_version = *(unsigned char*)(data + 4);
 121         if (graph_version != GRAPH_VERSION) {
 122                 error(_("graph version %X does not match version %X"),
 123                       graph_version, GRAPH_VERSION);
 124                 goto cleanup_fail;
 125         }
 126
 127         hash_version = *(unsigned char*)(data + 5);
 128         if (hash_version != GRAPH_OID_VERSION) {
 129                 error(_("hash version %X does not match version %X"),
 130                       hash_version, GRAPH_OID_VERSION);
 131                 goto cleanup_fail;
 132         }
 133
 134         graph = alloc_commit_graph();
 135
 136         graph->hash_len = GRAPH_OID_LEN;
 137         graph->num_chunks = *(unsigned char*)(data + 6);
 138         graph->graph_fd = fd;
 139         graph->data = graph_map;
 140         graph->data_len = graph_size;
 141
 142         last_chunk_id = 0;
 143         last_chunk_offset = 8;
 144         chunk_lookup = data + 8;
 145         for (i = 0; i < graph->num_chunks; i++) {
 146                 uint32_t chunk_id = get_be32(chunk_lookup + 0);
 147                 uint64_t chunk_offset = get_be64(chunk_lookup + 4);
 148                 int chunk_repeated = 0;
 149
 150                 chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
 151
 152                 if (chunk_offset > graph_size - GIT_MAX_RAWSZ) {
 153                         error(_("improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
 154                               (uint32_t)chunk_offset);
 155                         goto cleanup_fail;
 156                 }
 157
 158                 switch (chunk_id) {
 159                 case GRAPH_CHUNKID_OIDFANOUT:
 160                         if (graph->chunk_oid_fanout)
 161                                 chunk_repeated = 1;
 162                         else
 163                                 graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
 164                         break;
 165
 166                 case GRAPH_CHUNKID_OIDLOOKUP:
 167                         if (graph->chunk_oid_lookup)
 168                                 chunk_repeated = 1;
 169                         else
 170                                 graph->chunk_oid_lookup = data + chunk_offset;
 171                         break;
 172
 173                 case GRAPH_CHUNKID_DATA:
 174                         if (graph->chunk_commit_data)
 175                                 chunk_repeated = 1;
 176                         else
 177                                 graph->chunk_commit_data = data + chunk_offset;
 178                         break;
 179
 180                 case GRAPH_CHUNKID_LARGEEDGES:
 181                         if (graph->chunk_large_edges)
 182                                 chunk_repeated = 1;
 183                         else
 184                                 graph->chunk_large_edges = data + chunk_offset;
 185                         break;
 186                 }
 187
 188                 if (chunk_repeated) {
 189                         error(_("chunk id %08x appears multiple times"), chunk_id);
 190                         goto cleanup_fail;
 191                 }
 192
 193                 if (last_chunk_id == GRAPH_CHUNKID_OIDLOOKUP)
 194                 {
 195                         graph->num_commits = (chunk_offset - last_chunk_offset)
 196                                              / graph->hash_len;
 197                 }
 198
 199                 last_chunk_id = chunk_id;
 200                 last_chunk_offset = chunk_offset;
 201         }
 202
 203         return graph;
 204
 205 cleanup_fail:
 206         munmap(graph_map, graph_size);
 207         close(fd);
 208         exit(1);
 209 }
 210
 211 static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
 212 {
 213         char *graph_name;
 214
 215         if (r->objects->commit_graph)
 216                 return;
 217
 218         graph_name = get_commit_graph_filename(obj_dir);
 219         r->objects->commit_graph =
 220                 load_commit_graph_one(graph_name);
 221
 222         FREE_AND_NULL(graph_name);
 223 }
 224
 225 /*
 226  * Return 1 if commit_graph is non-NULL, and 0 otherwise.
 227  *
 228  * On the first invocation, this function attemps to load the commit
 229  * graph if the_repository is configured to have one.
 230  */
 231 static int prepare_commit_graph(struct repository *r)
 232 {
 233         struct alternate_object_database *alt;
 234         char *obj_dir;
 235         int config_value;
 236
 237         if (r->objects->commit_graph_attempted)
 238                 return !!r->objects->commit_graph;
 239         r->objects->commit_graph_attempted = 1;
 240
 241         if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
 242             (repo_config_get_bool(r, "core.commitgraph", &config_value) ||
 243             !config_value))
 244                 /*
 245                  * This repository is not configured to use commit graphs, so
 246                  * do not load one. (But report commit_graph_attempted anyway
 247                  * so that commit graph loading is not attempted again for this
 248                  * repository.)
 249                  */
 250                 return 0;
 251
 252         if (!commit_graph_compatible(r))
 253                 return 0;
 254
 255         obj_dir = r->objects->objectdir;
 256         prepare_commit_graph_one(r, obj_dir);
 257         prepare_alt_odb(r);
 258         for (alt = r->objects->alt_odb_list;
 259              !r->objects->commit_graph && alt;
 260              alt = alt->next)
 261                 prepare_commit_graph_one(r, alt->path);
 262         return !!r->objects->commit_graph;
 263 }
 264
 265 int generation_numbers_enabled(struct repository *r)
 266 {
 267         uint32_t first_generation;
 268         struct commit_graph *g;
 269         if (!prepare_commit_graph(r))
 270                return 0;
 271
 272         g = r->objects->commit_graph;
 273
 274         if (!g->num_commits)
 275                 return 0;
 276
 277         first_generation = get_be32(g->chunk_commit_data +
 278                                     g->hash_len + 8) >> 2;
 279
 280         return !!first_generation;
 281 }
 282
 283 void close_commit_graph(struct repository *r)
 284 {
 285         free_commit_graph(r->objects->commit_graph);
 286         r->objects->commit_graph = NULL;
 287 }
 288
 289 static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
 290 {
 291         return bsearch_hash(oid->hash, g->chunk_oid_fanout,
 292                             g->chunk_oid_lookup, g->hash_len, pos);
 293 }
 294
 295 static struct commit_list **insert_parent_or_die(struct commit_graph *g,
 296                                                  uint64_t pos,
 297                                                  struct commit_list **pptr)
 298 {
 299         struct commit *c;
 300         struct object_id oid;
 301
 302         if (pos >= g->num_commits)
 303                 die("invalid parent position %"PRIu64, pos);
 304
 305         hashcpy(oid.hash, g->chunk_oid_lookup + g->hash_len * pos);
 306         c = lookup_commit(the_repository, &oid);
 307         if (!c)
 308                 die(_("could not find commit %s"), oid_to_hex(&oid));
 309         c->graph_pos = pos;
 310         return &commit_list_insert(c, pptr)->next;
 311 }
 312
 313 static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
 314 {
 315         const unsigned char *commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * pos;
 316         item->graph_pos = pos;
 317         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 318 }
 319
 320 static int fill_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t pos)
 321 {
 322         uint32_t edge_value;
 323         uint32_t *parent_data_ptr;
 324         uint64_t date_low, date_high;
 325         struct commit_list **pptr;
 326         const unsigned char *commit_data = g->chunk_commit_data + (g->hash_len + 16) * pos;
 327
 328         item->object.parsed = 1;
 329         item->graph_pos = pos;
 330
 331         item->maybe_tree = NULL;
 332
 333         date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
 334         date_low = get_be32(commit_data + g->hash_len + 12);
 335         item->date = (timestamp_t)((date_high << 32) | date_low);
 336
 337         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 338
 339         pptr = &item->parents;
 340
 341         edge_value = get_be32(commit_data + g->hash_len);
 342         if (edge_value == GRAPH_PARENT_NONE)
 343                 return 1;
 344         pptr = insert_parent_or_die(g, edge_value, pptr);
 345
 346         edge_value = get_be32(commit_data + g->hash_len + 4);
 347         if (edge_value == GRAPH_PARENT_NONE)
 348                 return 1;
 349         if (!(edge_value & GRAPH_OCTOPUS_EDGES_NEEDED)) {
 350                 pptr = insert_parent_or_die(g, edge_value, pptr);
 351                 return 1;
 352         }
 353
 354         parent_data_ptr = (uint32_t*)(g->chunk_large_edges +
 355                           4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
 356         do {
 357                 edge_value = get_be32(parent_data_ptr);
 358                 pptr = insert_parent_or_die(g,
 359                                             edge_value & GRAPH_EDGE_LAST_MASK,
 360                                             pptr);
 361                 parent_data_ptr++;
 362         } while (!(edge_value & GRAPH_LAST_EDGE));
 363
 364         return 1;
 365 }
 366
 367 static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 368 {
 369         if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
 370                 *pos = item->graph_pos;
 371                 return 1;
 372         } else {
 373                 return bsearch_graph(g, &(item->object.oid), pos);
 374         }
 375 }
 376
 377 static int parse_commit_in_graph_one(struct commit_graph *g, struct commit *item)
 378 {
 379         uint32_t pos;
 380
 381         if (item->object.parsed)
 382                 return 1;
 383
 384         if (find_commit_in_graph(item, g, &pos))
 385                 return fill_commit_in_graph(item, g, pos);
 386
 387         return 0;
 388 }
 389
 390 int parse_commit_in_graph(struct repository *r, struct commit *item)
 391 {
 392         if (!prepare_commit_graph(r))
 393                 return 0;
 394         return parse_commit_in_graph_one(r->objects->commit_graph, item);
 395 }
 396
 397 void load_commit_graph_info(struct repository *r, struct commit *item)
 398 {
 399         uint32_t pos;
 400         if (!prepare_commit_graph(r))
 401                 return;
 402         if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
 403                 fill_commit_graph_info(item, r->objects->commit_graph, pos);
 404 }
 405
 406 static struct tree *load_tree_for_commit(struct commit_graph *g, struct commit *c)
 407 {
 408         struct object_id oid;
 409         const unsigned char *commit_data = g->chunk_commit_data +
 410                                            GRAPH_DATA_WIDTH * (c->graph_pos);
 411
 412         hashcpy(oid.hash, commit_data);
 413         c->maybe_tree = lookup_tree(the_repository, &oid);
 414
 415         return c->maybe_tree;
 416 }
 417
 418 static struct tree *get_commit_tree_in_graph_one(struct commit_graph *g,
 419                                                  const struct commit *c)
 420 {
 421         if (c->maybe_tree)
 422                 return c->maybe_tree;
 423         if (c->graph_pos == COMMIT_NOT_FROM_GRAPH)
 424                 BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
 425
 426         return load_tree_for_commit(g, (struct commit *)c);
 427 }
 428
 429 struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
 430 {
 431         return get_commit_tree_in_graph_one(r->objects->commit_graph, c);
 432 }
 433
 434 static void write_graph_chunk_fanout(struct hashfile *f,
 435                                      struct commit **commits,
 436                                      int nr_commits)
 437 {
 438         int i, count = 0;
 439         struct commit **list = commits;
 440
 441         /*
 442          * Write the first-level table (the list is sorted,
 443          * but we use a 256-entry lookup to be able to avoid
 444          * having to do eight extra binary search iterations).
 445          */
 446         for (i = 0; i < 256; i++) {
 447                 while (count < nr_commits) {
 448                         if ((*list)->object.oid.hash[0] != i)
 449                                 break;
 450                         count++;
 451                         list++;
 452                 }
 453
 454                 hashwrite_be32(f, count);
 455         }
 456 }
 457
 458 static void write_graph_chunk_oids(struct hashfile *f, int hash_len,
 459                                    struct commit **commits, int nr_commits)
 460 {
 461         struct commit **list = commits;
 462         int count;
 463         for (count = 0; count < nr_commits; count++, list++)
 464                 hashwrite(f, (*list)->object.oid.hash, (int)hash_len);
 465 }
 466
 467 static const unsigned char *commit_to_sha1(size_t index, void *table)
 468 {
 469         struct commit **commits = table;
 470         return commits[index]->object.oid.hash;
 471 }
 472
 473 static void write_graph_chunk_data(struct hashfile *f, int hash_len,
 474                                    struct commit **commits, int nr_commits)
 475 {
 476         struct commit **list = commits;
 477         struct commit **last = commits + nr_commits;
 478         uint32_t num_extra_edges = 0;
 479
 480         while (list < last) {
 481                 struct commit_list *parent;
 482                 int edge_value;
 483                 uint32_t packedDate[2];
 484
 485                 parse_commit(*list);
 486                 hashwrite(f, get_commit_tree_oid(*list)->hash, hash_len);
 487
 488                 parent = (*list)->parents;
 489
 490                 if (!parent)
 491                         edge_value = GRAPH_PARENT_NONE;
 492                 else {
 493                         edge_value = sha1_pos(parent->item->object.oid.hash,
 494                                               commits,
 495                                               nr_commits,
 496                                               commit_to_sha1);
 497
 498                         if (edge_value < 0)
 499                                 edge_value = GRAPH_PARENT_MISSING;
 500                 }
 501
 502                 hashwrite_be32(f, edge_value);
 503
 504                 if (parent)
 505                         parent = parent->next;
 506
 507                 if (!parent)
 508                         edge_value = GRAPH_PARENT_NONE;
 509                 else if (parent->next)
 510                         edge_value = GRAPH_OCTOPUS_EDGES_NEEDED | num_extra_edges;
 511                 else {
 512                         edge_value = sha1_pos(parent->item->object.oid.hash,
 513                                               commits,
 514                                               nr_commits,
 515                                               commit_to_sha1);
 516                         if (edge_value < 0)
 517                                 edge_value = GRAPH_PARENT_MISSING;
 518                 }
 519
 520                 hashwrite_be32(f, edge_value);
 521
 522                 if (edge_value & GRAPH_OCTOPUS_EDGES_NEEDED) {
 523                         do {
 524                                 num_extra_edges++;
 525                                 parent = parent->next;
 526                         } while (parent);
 527                 }
 528
 529                 if (sizeof((*list)->date) > 4)
 530                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
 531                 else
 532                         packedDate[0] = 0;
 533
 534                 packedDate[0] |= htonl((*list)->generation << 2);
 535
 536                 packedDate[1] = htonl((*list)->date);
 537                 hashwrite(f, packedDate, 8);
 538
 539                 list++;
 540         }
 541 }
 542
 543 static void write_graph_chunk_large_edges(struct hashfile *f,
 544                                           struct commit **commits,
 545                                           int nr_commits)
 546 {
 547         struct commit **list = commits;
 548         struct commit **last = commits + nr_commits;
 549         struct commit_list *parent;
 550
 551         while (list < last) {
 552                 int num_parents = 0;
 553                 for (parent = (*list)->parents; num_parents < 3 && parent;
 554                      parent = parent->next)
 555                         num_parents++;
 556
 557                 if (num_parents <= 2) {
 558                         list++;
 559                         continue;
 560                 }
 561
 562                 /* Since num_parents > 2, this initializer is safe. */
 563                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
 564                         int edge_value = sha1_pos(parent->item->object.oid.hash,
 565                                                   commits,
 566                                                   nr_commits,
 567                                                   commit_to_sha1);
 568
 569                         if (edge_value < 0)
 570                                 edge_value = GRAPH_PARENT_MISSING;
 571                         else if (!parent->next)
 572                                 edge_value |= GRAPH_LAST_EDGE;
 573
 574                         hashwrite_be32(f, edge_value);
 575                 }
 576
 577                 list++;
 578         }
 579 }
 580
 581 static int commit_compare(const void *_a, const void *_b)
 582 {
 583         const struct object_id *a = (const struct object_id *)_a;
 584         const struct object_id *b = (const struct object_id *)_b;
 585         return oidcmp(a, b);
 586 }
 587
 588 struct packed_commit_list {
 589         struct commit **list;
 590         int nr;
 591         int alloc;
 592 };
 593
 594 struct packed_oid_list {
 595         struct object_id *list;
 596         int nr;
 597         int alloc;
 598         struct progress *progress;
 599         int progress_done;
 600 };
 601
 602 static int add_packed_commits(const struct object_id *oid,
 603                               struct packed_git *pack,
 604                               uint32_t pos,
 605                               void *data)
 606 {
 607         struct packed_oid_list *list = (struct packed_oid_list*)data;
 608         enum object_type type;
 609         off_t offset = nth_packed_object_offset(pack, pos);
 610         struct object_info oi = OBJECT_INFO_INIT;
 611
 612         if (list->progress)
 613                 display_progress(list->progress, ++list->progress_done);
 614
 615         oi.typep = &type;
 616         if (packed_object_info(the_repository, pack, offset, &oi) < 0)
 617                 die(_("unable to get type of object %s"), oid_to_hex(oid));
 618
 619         if (type != OBJ_COMMIT)
 620                 return 0;
 621
 622         ALLOC_GROW(list->list, list->nr + 1, list->alloc);
 623         oidcpy(&(list->list[list->nr]), oid);
 624         list->nr++;
 625
 626         return 0;
 627 }
 628
 629 static void add_missing_parents(struct packed_oid_list *oids, struct commit *commit)
 630 {
 631         struct commit_list *parent;
 632         for (parent = commit->parents; parent; parent = parent->next) {
 633                 if (!(parent->item->object.flags & UNINTERESTING)) {
 634                         ALLOC_GROW(oids->list, oids->nr + 1, oids->alloc);
 635                         oidcpy(&oids->list[oids->nr], &(parent->item->object.oid));
 636                         oids->nr++;
 637                         parent->item->object.flags |= UNINTERESTING;
 638                 }
 639         }
 640 }
 641
 642 static void close_reachable(struct packed_oid_list *oids, int report_progress)
 643 {
 644         int i;
 645         struct commit *commit;
 646         struct progress *progress = NULL;
 647         int j = 0;
 648
 649         if (report_progress)
 650                 progress = start_delayed_progress(
 651                         _("Annotating commits in commit graph"), 0);
 652         for (i = 0; i < oids->nr; i++) {
 653                 display_progress(progress, ++j);
 654                 commit = lookup_commit(the_repository, &oids->list[i]);
 655                 if (commit)
 656                         commit->object.flags |= UNINTERESTING;
 657         }
 658
 659         /*
 660          * As this loop runs, oids->nr may grow, but not more
 661          * than the number of missing commits in the reachable
 662          * closure.
 663          */
 664         for (i = 0; i < oids->nr; i++) {
 665                 display_progress(progress, ++j);
 666                 commit = lookup_commit(the_repository, &oids->list[i]);
 667
 668                 if (commit && !parse_commit(commit))
 669                         add_missing_parents(oids, commit);
 670         }
 671
 672         for (i = 0; i < oids->nr; i++) {
 673                 display_progress(progress, ++j);
 674                 commit = lookup_commit(the_repository, &oids->list[i]);
 675
 676                 if (commit)
 677                         commit->object.flags &= ~UNINTERESTING;
 678         }
 679         stop_progress(&progress);
 680 }
 681
 682 static void compute_generation_numbers(struct packed_commit_list* commits,
 683                                        int report_progress)
 684 {
 685         int i;
 686         struct commit_list *list = NULL;
 687         struct progress *progress = NULL;
 688
 689         if (report_progress)
 690                 progress = start_progress(
 691                         _("Computing commit graph generation numbers"),
 692                         commits->nr);
 693         for (i = 0; i < commits->nr; i++) {
 694                 display_progress(progress, i + 1);
 695                 if (commits->list[i]->generation != GENERATION_NUMBER_INFINITY &&
 696                     commits->list[i]->generation != GENERATION_NUMBER_ZERO)
 697                         continue;
 698
 699                 commit_list_insert(commits->list[i], &list);
 700                 while (list) {
 701                         struct commit *current = list->item;
 702                         struct commit_list *parent;
 703                         int all_parents_computed = 1;
 704                         uint32_t max_generation = 0;
 705
 706                         for (parent = current->parents; parent; parent = parent->next) {
 707                                 if (parent->item->generation == GENERATION_NUMBER_INFINITY ||
 708                                     parent->item->generation == GENERATION_NUMBER_ZERO) {
 709                                         all_parents_computed = 0;
 710                                         commit_list_insert(parent->item, &list);
 711                                         break;
 712                                 } else if (parent->item->generation > max_generation) {
 713                                         max_generation = parent->item->generation;
 714                                 }
 715                         }
 716
 717                         if (all_parents_computed) {
 718                                 current->generation = max_generation + 1;
 719                                 pop_commit(&list);
 720
 721                                 if (current->generation > GENERATION_NUMBER_MAX)
 722                                         current->generation = GENERATION_NUMBER_MAX;
 723                         }
 724                 }
 725         }
 726         stop_progress(&progress);
 727 }
 728
 729 static int add_ref_to_list(const char *refname,
 730                            const struct object_id *oid,
 731                            int flags, void *cb_data)
 732 {
 733         struct string_list *list = (struct string_list *)cb_data;
 734
 735         string_list_append(list, oid_to_hex(oid));
 736         return 0;
 737 }
 738
 739 void write_commit_graph_reachable(const char *obj_dir, int append,
 740                                   int report_progress)
 741 {
 742         struct string_list list = STRING_LIST_INIT_DUP;
 743
 744         for_each_ref(add_ref_to_list, &list);
 745         write_commit_graph(obj_dir, NULL, &list, append, report_progress);
 746
 747         string_list_clear(&list, 0);
 748 }
 749
 750 void write_commit_graph(const char *obj_dir,
 751                         struct string_list *pack_indexes,
 752                         struct string_list *commit_hex,
 753                         int append, int report_progress)
 754 {
 755         struct packed_oid_list oids;
 756         struct packed_commit_list commits;
 757         struct hashfile *f;
 758         uint32_t i, count_distinct = 0;
 759         char *graph_name;
 760         struct lock_file lk = LOCK_INIT;
 761         uint32_t chunk_ids[5];
 762         uint64_t chunk_offsets[5];
 763         int num_chunks;
 764         int num_extra_edges;
 765         struct commit_list *parent;
 766         struct progress *progress = NULL;
 767
 768         if (!commit_graph_compatible(the_repository))
 769                 return;
 770
 771         oids.nr = 0;
 772         oids.alloc = approximate_object_count() / 32;
 773         oids.progress = NULL;
 774         oids.progress_done = 0;
 775
 776         if (append) {
 777                 prepare_commit_graph_one(the_repository, obj_dir);
 778                 if (the_repository->objects->commit_graph)
 779                         oids.alloc += the_repository->objects->commit_graph->num_commits;
 780         }
 781
 782         if (oids.alloc < 1024)
 783                 oids.alloc = 1024;
 784         ALLOC_ARRAY(oids.list, oids.alloc);
 785
 786         if (append && the_repository->objects->commit_graph) {
 787                 struct commit_graph *commit_graph =
 788                         the_repository->objects->commit_graph;
 789                 for (i = 0; i < commit_graph->num_commits; i++) {
 790                         const unsigned char *hash = commit_graph->chunk_oid_lookup +
 791                                 commit_graph->hash_len * i;
 792                         hashcpy(oids.list[oids.nr++].hash, hash);
 793                 }
 794         }
 795
 796         if (pack_indexes) {
 797                 struct strbuf packname = STRBUF_INIT;
 798                 int dirlen;
 799                 strbuf_addf(&packname, "%s/pack/", obj_dir);
 800                 dirlen = packname.len;
 801                 if (report_progress) {
 802                         oids.progress = start_delayed_progress(
 803                                 _("Finding commits for commit graph"), 0);
 804                         oids.progress_done = 0;
 805                 }
 806                 for (i = 0; i < pack_indexes->nr; i++) {
 807                         struct packed_git *p;
 808                         strbuf_setlen(&packname, dirlen);
 809                         strbuf_addstr(&packname, pack_indexes->items[i].string);
 810                         p = add_packed_git(packname.buf, packname.len, 1);
 811                         if (!p)
 812                                 die(_("error adding pack %s"), packname.buf);
 813                         if (open_pack_index(p))
 814                                 die(_("error opening index for %s"), packname.buf);
 815                         for_each_object_in_pack(p, add_packed_commits, &oids, 0);
 816                         close_pack(p);
 817                         free(p);
 818                 }
 819                 stop_progress(&oids.progress);
 820                 strbuf_release(&packname);
 821         }
 822
 823         if (commit_hex) {
 824                 if (report_progress)
 825                         progress = start_delayed_progress(
 826                                 _("Finding commits for commit graph"),
 827                                 commit_hex->nr);
 828                 for (i = 0; i < commit_hex->nr; i++) {
 829                         const char *end;
 830                         struct object_id oid;
 831                         struct commit *result;
 832
 833                         display_progress(progress, i + 1);
 834                         if (commit_hex->items[i].string &&
 835                             parse_oid_hex(commit_hex->items[i].string, &oid, &end))
 836                                 continue;
 837
 838                         result = lookup_commit_reference_gently(the_repository, &oid, 1);
 839
 840                         if (result) {
 841                                 ALLOC_GROW(oids.list, oids.nr + 1, oids.alloc);
 842                                 oidcpy(&oids.list[oids.nr], &(result->object.oid));
 843                                 oids.nr++;
 844                         }
 845                 }
 846                 stop_progress(&progress);
 847         }
 848
 849         if (!pack_indexes && !commit_hex) {
 850                 if (report_progress)
 851                         oids.progress = start_delayed_progress(
 852                                 _("Finding commits for commit graph"), 0);
 853                 for_each_packed_object(add_packed_commits, &oids, 0);
 854                 stop_progress(&oids.progress);
 855         }
 856
 857         close_reachable(&oids, report_progress);
 858
 859         QSORT(oids.list, oids.nr, commit_compare);
 860
 861         count_distinct = 1;
 862         for (i = 1; i < oids.nr; i++) {
 863                 if (!oideq(&oids.list[i - 1], &oids.list[i]))
 864                         count_distinct++;
 865         }
 866
 867         if (count_distinct >= GRAPH_PARENT_MISSING)
 868                 die(_("the commit graph format cannot write %d commits"), count_distinct);
 869
 870         commits.nr = 0;
 871         commits.alloc = count_distinct;
 872         ALLOC_ARRAY(commits.list, commits.alloc);
 873
 874         num_extra_edges = 0;
 875         for (i = 0; i < oids.nr; i++) {
 876                 int num_parents = 0;
 877                 if (i > 0 && oideq(&oids.list[i - 1], &oids.list[i]))
 878                         continue;
 879
 880                 commits.list[commits.nr] = lookup_commit(the_repository, &oids.list[i]);
 881                 parse_commit(commits.list[commits.nr]);
 882
 883                 for (parent = commits.list[commits.nr]->parents;
 884                      parent; parent = parent->next)
 885                         num_parents++;
 886
 887                 if (num_parents > 2)
 888                         num_extra_edges += num_parents - 1;
 889
 890                 commits.nr++;
 891         }
 892         num_chunks = num_extra_edges ? 4 : 3;
 893
 894         if (commits.nr >= GRAPH_PARENT_MISSING)
 895                 die(_("too many commits to write graph"));
 896
 897         compute_generation_numbers(&commits, report_progress);
 898
 899         graph_name = get_commit_graph_filename(obj_dir);
 900         if (safe_create_leading_directories(graph_name)) {
 901                 UNLEAK(graph_name);
 902                 die_errno(_("unable to create leading directories of %s"),
 903                           graph_name);
 904         }
 905
 906         hold_lock_file_for_update(&lk, graph_name, LOCK_DIE_ON_ERROR);
 907         f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
 908
 909         hashwrite_be32(f, GRAPH_SIGNATURE);
 910
 911         hashwrite_u8(f, GRAPH_VERSION);
 912         hashwrite_u8(f, GRAPH_OID_VERSION);
 913         hashwrite_u8(f, num_chunks);
 914         hashwrite_u8(f, 0); /* unused padding byte */
 915
 916         chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
 917         chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
 918         chunk_ids[2] = GRAPH_CHUNKID_DATA;
 919         if (num_extra_edges)
 920                 chunk_ids[3] = GRAPH_CHUNKID_LARGEEDGES;
 921         else
 922                 chunk_ids[3] = 0;
 923         chunk_ids[4] = 0;
 924
 925         chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
 926         chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
 927         chunk_offsets[2] = chunk_offsets[1] + GRAPH_OID_LEN * commits.nr;
 928         chunk_offsets[3] = chunk_offsets[2] + (GRAPH_OID_LEN + 16) * commits.nr;
 929         chunk_offsets[4] = chunk_offsets[3] + 4 * num_extra_edges;
 930
 931         for (i = 0; i <= num_chunks; i++) {
 932                 uint32_t chunk_write[3];
 933
 934                 chunk_write[0] = htonl(chunk_ids[i]);
 935                 chunk_write[1] = htonl(chunk_offsets[i] >> 32);
 936                 chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
 937                 hashwrite(f, chunk_write, 12);
 938         }
 939
 940         write_graph_chunk_fanout(f, commits.list, commits.nr);
 941         write_graph_chunk_oids(f, GRAPH_OID_LEN, commits.list, commits.nr);
 942         write_graph_chunk_data(f, GRAPH_OID_LEN, commits.list, commits.nr);
 943         write_graph_chunk_large_edges(f, commits.list, commits.nr);
 944
 945         close_commit_graph(the_repository);
 946         finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
 947         commit_lock_file(&lk);
 948
 949         free(graph_name);
 950         free(commits.list);
 951         free(oids.list);
 952 }
 953
 954 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
 955 static int verify_commit_graph_error;
 956
 957 static void graph_report(const char *fmt, ...)
 958 {
 959         va_list ap;
 960
 961         verify_commit_graph_error = 1;
 962         va_start(ap, fmt);
 963         vfprintf(stderr, fmt, ap);
 964         fprintf(stderr, "\n");
 965         va_end(ap);
 966 }
 967
 968 #define GENERATION_ZERO_EXISTS 1
 969 #define GENERATION_NUMBER_EXISTS 2
 970
 971 int verify_commit_graph(struct repository *r, struct commit_graph *g)
 972 {
 973         uint32_t i, cur_fanout_pos = 0;
 974         struct object_id prev_oid, cur_oid, checksum;
 975         int generation_zero = 0;
 976         struct hashfile *f;
 977         int devnull;
 978         struct progress *progress = NULL;
 979
 980         if (!g) {
 981                 graph_report("no commit-graph file loaded");
 982                 return 1;
 983         }
 984
 985         verify_commit_graph_error = 0;
 986
 987         if (!g->chunk_oid_fanout)
 988                 graph_report("commit-graph is missing the OID Fanout chunk");
 989         if (!g->chunk_oid_lookup)
 990                 graph_report("commit-graph is missing the OID Lookup chunk");
 991         if (!g->chunk_commit_data)
 992                 graph_report("commit-graph is missing the Commit Data chunk");
 993
 994         if (verify_commit_graph_error)
 995                 return verify_commit_graph_error;
 996
 997         devnull = open("/dev/null", O_WRONLY);
 998         f = hashfd(devnull, NULL);
 999         hashwrite(f, g->data, g->data_len - g->hash_len);
1000         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
1001         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
1002                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
1003                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
1004         }
1005
1006         for (i = 0; i < g->num_commits; i++) {
1007                 struct commit *graph_commit;
1008
1009                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1010
1011                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
1012                         graph_report("commit-graph has incorrect OID order: %s then %s",
1013                                      oid_to_hex(&prev_oid),
1014                                      oid_to_hex(&cur_oid));
1015
1016                 oidcpy(&prev_oid, &cur_oid);
1017
1018                 while (cur_oid.hash[0] > cur_fanout_pos) {
1019                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1020
1021                         if (i != fanout_value)
1022                                 graph_report("commit-graph has incorrect fanout value: fanout[%d] = %u != %u",
1023                                              cur_fanout_pos, fanout_value, i);
1024                         cur_fanout_pos++;
1025                 }
1026
1027                 graph_commit = lookup_commit(r, &cur_oid);
1028                 if (!parse_commit_in_graph_one(g, graph_commit))
1029                         graph_report("failed to parse %s from commit-graph",
1030                                      oid_to_hex(&cur_oid));
1031         }
1032
1033         while (cur_fanout_pos < 256) {
1034                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1035
1036                 if (g->num_commits != fanout_value)
1037                         graph_report("commit-graph has incorrect fanout value: fanout[%d] = %u != %u",
1038                                      cur_fanout_pos, fanout_value, i);
1039
1040                 cur_fanout_pos++;
1041         }
1042
1043         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
1044                 return verify_commit_graph_error;
1045
1046         progress = start_progress(_("Verifying commits in commit graph"),
1047                                   g->num_commits);
1048         for (i = 0; i < g->num_commits; i++) {
1049                 struct commit *graph_commit, *odb_commit;
1050                 struct commit_list *graph_parents, *odb_parents;
1051                 uint32_t max_generation = 0;
1052
1053                 display_progress(progress, i + 1);
1054                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1055
1056                 graph_commit = lookup_commit(r, &cur_oid);
1057                 odb_commit = (struct commit *)create_object(r, cur_oid.hash, alloc_commit_node(r));
1058                 if (parse_commit_internal(odb_commit, 0, 0)) {
1059                         graph_report("failed to parse %s from object database",
1060                                      oid_to_hex(&cur_oid));
1061                         continue;
1062                 }
1063
1064                 if (!oideq(&get_commit_tree_in_graph_one(g, graph_commit)->object.oid,
1065                            get_commit_tree_oid(odb_commit)))
1066                         graph_report("root tree OID for commit %s in commit-graph is %s != %s",
1067                                      oid_to_hex(&cur_oid),
1068                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
1069                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
1070
1071                 graph_parents = graph_commit->parents;
1072                 odb_parents = odb_commit->parents;
1073
1074                 while (graph_parents) {
1075                         if (odb_parents == NULL) {
1076                                 graph_report("commit-graph parent list for commit %s is too long",
1077                                              oid_to_hex(&cur_oid));
1078                                 break;
1079                         }
1080
1081                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
1082                                 graph_report("commit-graph parent for %s is %s != %s",
1083                                              oid_to_hex(&cur_oid),
1084                                              oid_to_hex(&graph_parents->item->object.oid),
1085                                              oid_to_hex(&odb_parents->item->object.oid));
1086
1087                         if (graph_parents->item->generation > max_generation)
1088                                 max_generation = graph_parents->item->generation;
1089
1090                         graph_parents = graph_parents->next;
1091                         odb_parents = odb_parents->next;
1092                 }
1093
1094                 if (odb_parents != NULL)
1095                         graph_report("commit-graph parent list for commit %s terminates early",
1096                                      oid_to_hex(&cur_oid));
1097
1098                 if (!graph_commit->generation) {
1099                         if (generation_zero == GENERATION_NUMBER_EXISTS)
1100                                 graph_report("commit-graph has generation number zero for commit %s, but non-zero elsewhere",
1101                                              oid_to_hex(&cur_oid));
1102                         generation_zero = GENERATION_ZERO_EXISTS;
1103                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
1104                         graph_report("commit-graph has non-zero generation number for commit %s, but zero elsewhere",
1105                                      oid_to_hex(&cur_oid));
1106
1107                 if (generation_zero == GENERATION_ZERO_EXISTS)
1108                         continue;
1109
1110                 /*
1111                  * If one of our parents has generation GENERATION_NUMBER_MAX, then
1112                  * our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
1113                  * extra logic in the following condition.
1114                  */
1115                 if (max_generation == GENERATION_NUMBER_MAX)
1116                         max_generation--;
1117
1118                 if (graph_commit->generation != max_generation + 1)
1119                         graph_report("commit-graph generation for commit %s is %u != %u",
1120                                      oid_to_hex(&cur_oid),
1121                                      graph_commit->generation,
1122                                      max_generation + 1);
1123
1124                 if (graph_commit->date != odb_commit->date)
1125                         graph_report("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime,
1126                                      oid_to_hex(&cur_oid),
1127                                      graph_commit->date,
1128                                      odb_commit->date);
1129         }
1130         stop_progress(&progress);
1131
1132         return verify_commit_graph_error;
1133 }
1134
1135 void free_commit_graph(struct commit_graph *g)
1136 {
1137         if (!g)
1138                 return;
1139         if (g->graph_fd >= 0) {
1140                 munmap((void *)g->data, g->data_len);
1141                 g->data = NULL;
1142                 close(g->graph_fd);
1143         }
1144         free(g);
1145 }