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