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 repository *r,
 296                                                  struct commit_graph *g,
 297                                                  uint64_t pos,
 298                                                  struct commit_list **pptr)
 299 {
 300         struct commit *c;
 301         struct object_id oid;
 302
 303         if (pos >= g->num_commits)
 304                 die("invalid parent position %"PRIu64, pos);
 305
 306         hashcpy(oid.hash, g->chunk_oid_lookup + g->hash_len * pos);
 307         c = lookup_commit(r, &oid);
 308         if (!c)
 309                 die(_("could not find commit %s"), oid_to_hex(&oid));
 310         c->graph_pos = pos;
 311         return &commit_list_insert(c, pptr)->next;
 312 }
 313
 314 static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
 315 {
 316         const unsigned char *commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * pos;
 317         item->graph_pos = pos;
 318         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 319 }
 320
 321 static int fill_commit_in_graph(struct repository *r,
 322                                 struct commit *item,
 323                                 struct commit_graph *g, uint32_t pos)
 324 {
 325         uint32_t edge_value;
 326         uint32_t *parent_data_ptr;
 327         uint64_t date_low, date_high;
 328         struct commit_list **pptr;
 329         const unsigned char *commit_data = g->chunk_commit_data + (g->hash_len + 16) * pos;
 330
 331         item->object.parsed = 1;
 332         item->graph_pos = pos;
 333
 334         item->maybe_tree = NULL;
 335
 336         date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
 337         date_low = get_be32(commit_data + g->hash_len + 12);
 338         item->date = (timestamp_t)((date_high << 32) | date_low);
 339
 340         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 341
 342         pptr = &item->parents;
 343
 344         edge_value = get_be32(commit_data + g->hash_len);
 345         if (edge_value == GRAPH_PARENT_NONE)
 346                 return 1;
 347         pptr = insert_parent_or_die(r, g, edge_value, pptr);
 348
 349         edge_value = get_be32(commit_data + g->hash_len + 4);
 350         if (edge_value == GRAPH_PARENT_NONE)
 351                 return 1;
 352         if (!(edge_value & GRAPH_OCTOPUS_EDGES_NEEDED)) {
 353                 pptr = insert_parent_or_die(r, g, edge_value, pptr);
 354                 return 1;
 355         }
 356
 357         parent_data_ptr = (uint32_t*)(g->chunk_large_edges +
 358                           4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
 359         do {
 360                 edge_value = get_be32(parent_data_ptr);
 361                 pptr = insert_parent_or_die(r, g,
 362                                             edge_value & GRAPH_EDGE_LAST_MASK,
 363                                             pptr);
 364                 parent_data_ptr++;
 365         } while (!(edge_value & GRAPH_LAST_EDGE));
 366
 367         return 1;
 368 }
 369
 370 static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 371 {
 372         if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
 373                 *pos = item->graph_pos;
 374                 return 1;
 375         } else {
 376                 return bsearch_graph(g, &(item->object.oid), pos);
 377         }
 378 }
 379
 380 static int parse_commit_in_graph_one(struct repository *r,
 381                                      struct commit_graph *g,
 382                                      struct commit *item)
 383 {
 384         uint32_t pos;
 385
 386         if (item->object.parsed)
 387                 return 1;
 388
 389         if (find_commit_in_graph(item, g, &pos))
 390                 return fill_commit_in_graph(r, item, g, pos);
 391
 392         return 0;
 393 }
 394
 395 int parse_commit_in_graph(struct repository *r, struct commit *item)
 396 {
 397         if (!prepare_commit_graph(r))
 398                 return 0;
 399         return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
 400 }
 401
 402 void load_commit_graph_info(struct repository *r, struct commit *item)
 403 {
 404         uint32_t pos;
 405         if (!prepare_commit_graph(r))
 406                 return;
 407         if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
 408                 fill_commit_graph_info(item, r->objects->commit_graph, pos);
 409 }
 410
 411 static struct tree *load_tree_for_commit(struct repository *r,
 412                                          struct commit_graph *g,
 413                                          struct commit *c)
 414 {
 415         struct object_id oid;
 416         const unsigned char *commit_data = g->chunk_commit_data +
 417                                            GRAPH_DATA_WIDTH * (c->graph_pos);
 418
 419         hashcpy(oid.hash, commit_data);
 420         c->maybe_tree = lookup_tree(r, &oid);
 421
 422         return c->maybe_tree;
 423 }
 424
 425 static struct tree *get_commit_tree_in_graph_one(struct repository *r,
 426                                                  struct commit_graph *g,
 427                                                  const struct commit *c)
 428 {
 429         if (c->maybe_tree)
 430                 return c->maybe_tree;
 431         if (c->graph_pos == COMMIT_NOT_FROM_GRAPH)
 432                 BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
 433
 434         return load_tree_for_commit(r, g, (struct commit *)c);
 435 }
 436
 437 struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
 438 {
 439         return get_commit_tree_in_graph_one(r, r->objects->commit_graph, c);
 440 }
 441
 442 static void write_graph_chunk_fanout(struct hashfile *f,
 443                                      struct commit **commits,
 444                                      int nr_commits)
 445 {
 446         int i, count = 0;
 447         struct commit **list = commits;
 448
 449         /*
 450          * Write the first-level table (the list is sorted,
 451          * but we use a 256-entry lookup to be able to avoid
 452          * having to do eight extra binary search iterations).
 453          */
 454         for (i = 0; i < 256; i++) {
 455                 while (count < nr_commits) {
 456                         if ((*list)->object.oid.hash[0] != i)
 457                                 break;
 458                         count++;
 459                         list++;
 460                 }
 461
 462                 hashwrite_be32(f, count);
 463         }
 464 }
 465
 466 static void write_graph_chunk_oids(struct hashfile *f, int hash_len,
 467                                    struct commit **commits, int nr_commits)
 468 {
 469         struct commit **list = commits;
 470         int count;
 471         for (count = 0; count < nr_commits; count++, list++)
 472                 hashwrite(f, (*list)->object.oid.hash, (int)hash_len);
 473 }
 474
 475 static const unsigned char *commit_to_sha1(size_t index, void *table)
 476 {
 477         struct commit **commits = table;
 478         return commits[index]->object.oid.hash;
 479 }
 480
 481 static void write_graph_chunk_data(struct hashfile *f, int hash_len,
 482                                    struct commit **commits, int nr_commits)
 483 {
 484         struct commit **list = commits;
 485         struct commit **last = commits + nr_commits;
 486         uint32_t num_extra_edges = 0;
 487
 488         while (list < last) {
 489                 struct commit_list *parent;
 490                 int edge_value;
 491                 uint32_t packedDate[2];
 492
 493                 parse_commit(*list);
 494                 hashwrite(f, get_commit_tree_oid(*list)->hash, hash_len);
 495
 496                 parent = (*list)->parents;
 497
 498                 if (!parent)
 499                         edge_value = GRAPH_PARENT_NONE;
 500                 else {
 501                         edge_value = sha1_pos(parent->item->object.oid.hash,
 502                                               commits,
 503                                               nr_commits,
 504                                               commit_to_sha1);
 505
 506                         if (edge_value < 0)
 507                                 edge_value = GRAPH_PARENT_MISSING;
 508                 }
 509
 510                 hashwrite_be32(f, edge_value);
 511
 512                 if (parent)
 513                         parent = parent->next;
 514
 515                 if (!parent)
 516                         edge_value = GRAPH_PARENT_NONE;
 517                 else if (parent->next)
 518                         edge_value = GRAPH_OCTOPUS_EDGES_NEEDED | num_extra_edges;
 519                 else {
 520                         edge_value = sha1_pos(parent->item->object.oid.hash,
 521                                               commits,
 522                                               nr_commits,
 523                                               commit_to_sha1);
 524                         if (edge_value < 0)
 525                                 edge_value = GRAPH_PARENT_MISSING;
 526                 }
 527
 528                 hashwrite_be32(f, edge_value);
 529
 530                 if (edge_value & GRAPH_OCTOPUS_EDGES_NEEDED) {
 531                         do {
 532                                 num_extra_edges++;
 533                                 parent = parent->next;
 534                         } while (parent);
 535                 }
 536
 537                 if (sizeof((*list)->date) > 4)
 538                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
 539                 else
 540                         packedDate[0] = 0;
 541
 542                 packedDate[0] |= htonl((*list)->generation << 2);
 543
 544                 packedDate[1] = htonl((*list)->date);
 545                 hashwrite(f, packedDate, 8);
 546
 547                 list++;
 548         }
 549 }
 550
 551 static void write_graph_chunk_large_edges(struct hashfile *f,
 552                                           struct commit **commits,
 553                                           int nr_commits)
 554 {
 555         struct commit **list = commits;
 556         struct commit **last = commits + nr_commits;
 557         struct commit_list *parent;
 558
 559         while (list < last) {
 560                 int num_parents = 0;
 561                 for (parent = (*list)->parents; num_parents < 3 && parent;
 562                      parent = parent->next)
 563                         num_parents++;
 564
 565                 if (num_parents <= 2) {
 566                         list++;
 567                         continue;
 568                 }
 569
 570                 /* Since num_parents > 2, this initializer is safe. */
 571                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
 572                         int edge_value = sha1_pos(parent->item->object.oid.hash,
 573                                                   commits,
 574                                                   nr_commits,
 575                                                   commit_to_sha1);
 576
 577                         if (edge_value < 0)
 578                                 edge_value = GRAPH_PARENT_MISSING;
 579                         else if (!parent->next)
 580                                 edge_value |= GRAPH_LAST_EDGE;
 581
 582                         hashwrite_be32(f, edge_value);
 583                 }
 584
 585                 list++;
 586         }
 587 }
 588
 589 static int commit_compare(const void *_a, const void *_b)
 590 {
 591         const struct object_id *a = (const struct object_id *)_a;
 592         const struct object_id *b = (const struct object_id *)_b;
 593         return oidcmp(a, b);
 594 }
 595
 596 struct packed_commit_list {
 597         struct commit **list;
 598         int nr;
 599         int alloc;
 600 };
 601
 602 struct packed_oid_list {
 603         struct object_id *list;
 604         int nr;
 605         int alloc;
 606         struct progress *progress;
 607         int progress_done;
 608 };
 609
 610 static int add_packed_commits(const struct object_id *oid,
 611                               struct packed_git *pack,
 612                               uint32_t pos,
 613                               void *data)
 614 {
 615         struct packed_oid_list *list = (struct packed_oid_list*)data;
 616         enum object_type type;
 617         off_t offset = nth_packed_object_offset(pack, pos);
 618         struct object_info oi = OBJECT_INFO_INIT;
 619
 620         if (list->progress)
 621                 display_progress(list->progress, ++list->progress_done);
 622
 623         oi.typep = &type;
 624         if (packed_object_info(the_repository, pack, offset, &oi) < 0)
 625                 die(_("unable to get type of object %s"), oid_to_hex(oid));
 626
 627         if (type != OBJ_COMMIT)
 628                 return 0;
 629
 630         ALLOC_GROW(list->list, list->nr + 1, list->alloc);
 631         oidcpy(&(list->list[list->nr]), oid);
 632         list->nr++;
 633
 634         return 0;
 635 }
 636
 637 static void add_missing_parents(struct packed_oid_list *oids, struct commit *commit)
 638 {
 639         struct commit_list *parent;
 640         for (parent = commit->parents; parent; parent = parent->next) {
 641                 if (!(parent->item->object.flags & UNINTERESTING)) {
 642                         ALLOC_GROW(oids->list, oids->nr + 1, oids->alloc);
 643                         oidcpy(&oids->list[oids->nr], &(parent->item->object.oid));
 644                         oids->nr++;
 645                         parent->item->object.flags |= UNINTERESTING;
 646                 }
 647         }
 648 }
 649
 650 static void close_reachable(struct packed_oid_list *oids, int report_progress)
 651 {
 652         int i;
 653         struct commit *commit;
 654         struct progress *progress = NULL;
 655         int j = 0;
 656
 657         if (report_progress)
 658                 progress = start_delayed_progress(
 659                         _("Annotating commits in commit graph"), 0);
 660         for (i = 0; i < oids->nr; i++) {
 661                 display_progress(progress, ++j);
 662                 commit = lookup_commit(the_repository, &oids->list[i]);
 663                 if (commit)
 664                         commit->object.flags |= UNINTERESTING;
 665         }
 666
 667         /*
 668          * As this loop runs, oids->nr may grow, but not more
 669          * than the number of missing commits in the reachable
 670          * closure.
 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 && !parse_commit(commit))
 677                         add_missing_parents(oids, commit);
 678         }
 679
 680         for (i = 0; i < oids->nr; i++) {
 681                 display_progress(progress, ++j);
 682                 commit = lookup_commit(the_repository, &oids->list[i]);
 683
 684                 if (commit)
 685                         commit->object.flags &= ~UNINTERESTING;
 686         }
 687         stop_progress(&progress);
 688 }
 689
 690 static void compute_generation_numbers(struct packed_commit_list* commits,
 691                                        int report_progress)
 692 {
 693         int i;
 694         struct commit_list *list = NULL;
 695         struct progress *progress = NULL;
 696
 697         if (report_progress)
 698                 progress = start_progress(
 699                         _("Computing commit graph generation numbers"),
 700                         commits->nr);
 701         for (i = 0; i < commits->nr; i++) {
 702                 display_progress(progress, i + 1);
 703                 if (commits->list[i]->generation != GENERATION_NUMBER_INFINITY &&
 704                     commits->list[i]->generation != GENERATION_NUMBER_ZERO)
 705                         continue;
 706
 707                 commit_list_insert(commits->list[i], &list);
 708                 while (list) {
 709                         struct commit *current = list->item;
 710                         struct commit_list *parent;
 711                         int all_parents_computed = 1;
 712                         uint32_t max_generation = 0;
 713
 714                         for (parent = current->parents; parent; parent = parent->next) {
 715                                 if (parent->item->generation == GENERATION_NUMBER_INFINITY ||
 716                                     parent->item->generation == GENERATION_NUMBER_ZERO) {
 717                                         all_parents_computed = 0;
 718                                         commit_list_insert(parent->item, &list);
 719                                         break;
 720                                 } else if (parent->item->generation > max_generation) {
 721                                         max_generation = parent->item->generation;
 722                                 }
 723                         }
 724
 725                         if (all_parents_computed) {
 726                                 current->generation = max_generation + 1;
 727                                 pop_commit(&list);
 728
 729                                 if (current->generation > GENERATION_NUMBER_MAX)
 730                                         current->generation = GENERATION_NUMBER_MAX;
 731                         }
 732                 }
 733         }
 734         stop_progress(&progress);
 735 }
 736
 737 static int add_ref_to_list(const char *refname,
 738                            const struct object_id *oid,
 739                            int flags, void *cb_data)
 740 {
 741         struct string_list *list = (struct string_list *)cb_data;
 742
 743         string_list_append(list, oid_to_hex(oid));
 744         return 0;
 745 }
 746
 747 void write_commit_graph_reachable(const char *obj_dir, int append,
 748                                   int report_progress)
 749 {
 750         struct string_list list = STRING_LIST_INIT_DUP;
 751
 752         for_each_ref(add_ref_to_list, &list);
 753         write_commit_graph(obj_dir, NULL, &list, append, report_progress);
 754
 755         string_list_clear(&list, 0);
 756 }
 757
 758 void write_commit_graph(const char *obj_dir,
 759                         struct string_list *pack_indexes,
 760                         struct string_list *commit_hex,
 761                         int append, int report_progress)
 762 {
 763         struct packed_oid_list oids;
 764         struct packed_commit_list commits;
 765         struct hashfile *f;
 766         uint32_t i, count_distinct = 0;
 767         char *graph_name;
 768         struct lock_file lk = LOCK_INIT;
 769         uint32_t chunk_ids[5];
 770         uint64_t chunk_offsets[5];
 771         int num_chunks;
 772         int num_extra_edges;
 773         struct commit_list *parent;
 774         struct progress *progress = NULL;
 775
 776         if (!commit_graph_compatible(the_repository))
 777                 return;
 778
 779         oids.nr = 0;
 780         oids.alloc = approximate_object_count() / 32;
 781         oids.progress = NULL;
 782         oids.progress_done = 0;
 783
 784         if (append) {
 785                 prepare_commit_graph_one(the_repository, obj_dir);
 786                 if (the_repository->objects->commit_graph)
 787                         oids.alloc += the_repository->objects->commit_graph->num_commits;
 788         }
 789
 790         if (oids.alloc < 1024)
 791                 oids.alloc = 1024;
 792         ALLOC_ARRAY(oids.list, oids.alloc);
 793
 794         if (append && the_repository->objects->commit_graph) {
 795                 struct commit_graph *commit_graph =
 796                         the_repository->objects->commit_graph;
 797                 for (i = 0; i < commit_graph->num_commits; i++) {
 798                         const unsigned char *hash = commit_graph->chunk_oid_lookup +
 799                                 commit_graph->hash_len * i;
 800                         hashcpy(oids.list[oids.nr++].hash, hash);
 801                 }
 802         }
 803
 804         if (pack_indexes) {
 805                 struct strbuf packname = STRBUF_INIT;
 806                 int dirlen;
 807                 strbuf_addf(&packname, "%s/pack/", obj_dir);
 808                 dirlen = packname.len;
 809                 if (report_progress) {
 810                         oids.progress = start_delayed_progress(
 811                                 _("Finding commits for commit graph"), 0);
 812                         oids.progress_done = 0;
 813                 }
 814                 for (i = 0; i < pack_indexes->nr; i++) {
 815                         struct packed_git *p;
 816                         strbuf_setlen(&packname, dirlen);
 817                         strbuf_addstr(&packname, pack_indexes->items[i].string);
 818                         p = add_packed_git(packname.buf, packname.len, 1);
 819                         if (!p)
 820                                 die(_("error adding pack %s"), packname.buf);
 821                         if (open_pack_index(p))
 822                                 die(_("error opening index for %s"), packname.buf);
 823                         for_each_object_in_pack(p, add_packed_commits, &oids, 0);
 824                         close_pack(p);
 825                         free(p);
 826                 }
 827                 stop_progress(&oids.progress);
 828                 strbuf_release(&packname);
 829         }
 830
 831         if (commit_hex) {
 832                 if (report_progress)
 833                         progress = start_delayed_progress(
 834                                 _("Finding commits for commit graph"),
 835                                 commit_hex->nr);
 836                 for (i = 0; i < commit_hex->nr; i++) {
 837                         const char *end;
 838                         struct object_id oid;
 839                         struct commit *result;
 840
 841                         display_progress(progress, i + 1);
 842                         if (commit_hex->items[i].string &&
 843                             parse_oid_hex(commit_hex->items[i].string, &oid, &end))
 844                                 continue;
 845
 846                         result = lookup_commit_reference_gently(the_repository, &oid, 1);
 847
 848                         if (result) {
 849                                 ALLOC_GROW(oids.list, oids.nr + 1, oids.alloc);
 850                                 oidcpy(&oids.list[oids.nr], &(result->object.oid));
 851                                 oids.nr++;
 852                         }
 853                 }
 854                 stop_progress(&progress);
 855         }
 856
 857         if (!pack_indexes && !commit_hex) {
 858                 if (report_progress)
 859                         oids.progress = start_delayed_progress(
 860                                 _("Finding commits for commit graph"), 0);
 861                 for_each_packed_object(add_packed_commits, &oids, 0);
 862                 stop_progress(&oids.progress);
 863         }
 864
 865         close_reachable(&oids, report_progress);
 866
 867         QSORT(oids.list, oids.nr, commit_compare);
 868
 869         count_distinct = 1;
 870         for (i = 1; i < oids.nr; i++) {
 871                 if (!oideq(&oids.list[i - 1], &oids.list[i]))
 872                         count_distinct++;
 873         }
 874
 875         if (count_distinct >= GRAPH_PARENT_MISSING)
 876                 die(_("the commit graph format cannot write %d commits"), count_distinct);
 877
 878         commits.nr = 0;
 879         commits.alloc = count_distinct;
 880         ALLOC_ARRAY(commits.list, commits.alloc);
 881
 882         num_extra_edges = 0;
 883         for (i = 0; i < oids.nr; i++) {
 884                 int num_parents = 0;
 885                 if (i > 0 && oideq(&oids.list[i - 1], &oids.list[i]))
 886                         continue;
 887
 888                 commits.list[commits.nr] = lookup_commit(the_repository, &oids.list[i]);
 889                 parse_commit(commits.list[commits.nr]);
 890
 891                 for (parent = commits.list[commits.nr]->parents;
 892                      parent; parent = parent->next)
 893                         num_parents++;
 894
 895                 if (num_parents > 2)
 896                         num_extra_edges += num_parents - 1;
 897
 898                 commits.nr++;
 899         }
 900         num_chunks = num_extra_edges ? 4 : 3;
 901
 902         if (commits.nr >= GRAPH_PARENT_MISSING)
 903                 die(_("too many commits to write graph"));
 904
 905         compute_generation_numbers(&commits, report_progress);
 906
 907         graph_name = get_commit_graph_filename(obj_dir);
 908         if (safe_create_leading_directories(graph_name)) {
 909                 UNLEAK(graph_name);
 910                 die_errno(_("unable to create leading directories of %s"),
 911                           graph_name);
 912         }
 913
 914         hold_lock_file_for_update(&lk, graph_name, LOCK_DIE_ON_ERROR);
 915         f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
 916
 917         hashwrite_be32(f, GRAPH_SIGNATURE);
 918
 919         hashwrite_u8(f, GRAPH_VERSION);
 920         hashwrite_u8(f, GRAPH_OID_VERSION);
 921         hashwrite_u8(f, num_chunks);
 922         hashwrite_u8(f, 0); /* unused padding byte */
 923
 924         chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
 925         chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
 926         chunk_ids[2] = GRAPH_CHUNKID_DATA;
 927         if (num_extra_edges)
 928                 chunk_ids[3] = GRAPH_CHUNKID_LARGEEDGES;
 929         else
 930                 chunk_ids[3] = 0;
 931         chunk_ids[4] = 0;
 932
 933         chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
 934         chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
 935         chunk_offsets[2] = chunk_offsets[1] + GRAPH_OID_LEN * commits.nr;
 936         chunk_offsets[3] = chunk_offsets[2] + (GRAPH_OID_LEN + 16) * commits.nr;
 937         chunk_offsets[4] = chunk_offsets[3] + 4 * num_extra_edges;
 938
 939         for (i = 0; i <= num_chunks; i++) {
 940                 uint32_t chunk_write[3];
 941
 942                 chunk_write[0] = htonl(chunk_ids[i]);
 943                 chunk_write[1] = htonl(chunk_offsets[i] >> 32);
 944                 chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
 945                 hashwrite(f, chunk_write, 12);
 946         }
 947
 948         write_graph_chunk_fanout(f, commits.list, commits.nr);
 949         write_graph_chunk_oids(f, GRAPH_OID_LEN, commits.list, commits.nr);
 950         write_graph_chunk_data(f, GRAPH_OID_LEN, commits.list, commits.nr);
 951         write_graph_chunk_large_edges(f, commits.list, commits.nr);
 952
 953         close_commit_graph(the_repository);
 954         finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
 955         commit_lock_file(&lk);
 956
 957         free(graph_name);
 958         free(commits.list);
 959         free(oids.list);
 960 }
 961
 962 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
 963 static int verify_commit_graph_error;
 964
 965 static void graph_report(const char *fmt, ...)
 966 {
 967         va_list ap;
 968
 969         verify_commit_graph_error = 1;
 970         va_start(ap, fmt);
 971         vfprintf(stderr, fmt, ap);
 972         fprintf(stderr, "\n");
 973         va_end(ap);
 974 }
 975
 976 #define GENERATION_ZERO_EXISTS 1
 977 #define GENERATION_NUMBER_EXISTS 2
 978
 979 int verify_commit_graph(struct repository *r, struct commit_graph *g)
 980 {
 981         uint32_t i, cur_fanout_pos = 0;
 982         struct object_id prev_oid, cur_oid, checksum;
 983         int generation_zero = 0;
 984         struct hashfile *f;
 985         int devnull;
 986         struct progress *progress = NULL;
 987
 988         if (!g) {
 989                 graph_report("no commit-graph file loaded");
 990                 return 1;
 991         }
 992
 993         verify_commit_graph_error = 0;
 994
 995         if (!g->chunk_oid_fanout)
 996                 graph_report("commit-graph is missing the OID Fanout chunk");
 997         if (!g->chunk_oid_lookup)
 998                 graph_report("commit-graph is missing the OID Lookup chunk");
 999         if (!g->chunk_commit_data)
1000                 graph_report("commit-graph is missing the Commit Data chunk");
1001
1002         if (verify_commit_graph_error)
1003                 return verify_commit_graph_error;
1004
1005         devnull = open("/dev/null", O_WRONLY);
1006         f = hashfd(devnull, NULL);
1007         hashwrite(f, g->data, g->data_len - g->hash_len);
1008         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
1009         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
1010                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
1011                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
1012         }
1013
1014         for (i = 0; i < g->num_commits; i++) {
1015                 struct commit *graph_commit;
1016
1017                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1018
1019                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
1020                         graph_report("commit-graph has incorrect OID order: %s then %s",
1021                                      oid_to_hex(&prev_oid),
1022                                      oid_to_hex(&cur_oid));
1023
1024                 oidcpy(&prev_oid, &cur_oid);
1025
1026                 while (cur_oid.hash[0] > cur_fanout_pos) {
1027                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1028
1029                         if (i != fanout_value)
1030                                 graph_report("commit-graph has incorrect fanout value: fanout[%d] = %u != %u",
1031                                              cur_fanout_pos, fanout_value, i);
1032                         cur_fanout_pos++;
1033                 }
1034
1035                 graph_commit = lookup_commit(r, &cur_oid);
1036                 if (!parse_commit_in_graph_one(r, g, graph_commit))
1037                         graph_report("failed to parse %s from commit-graph",
1038                                      oid_to_hex(&cur_oid));
1039         }
1040
1041         while (cur_fanout_pos < 256) {
1042                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1043
1044                 if (g->num_commits != fanout_value)
1045                         graph_report("commit-graph has incorrect fanout value: fanout[%d] = %u != %u",
1046                                      cur_fanout_pos, fanout_value, i);
1047
1048                 cur_fanout_pos++;
1049         }
1050
1051         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
1052                 return verify_commit_graph_error;
1053
1054         progress = start_progress(_("Verifying commits in commit graph"),
1055                                   g->num_commits);
1056         for (i = 0; i < g->num_commits; i++) {
1057                 struct commit *graph_commit, *odb_commit;
1058                 struct commit_list *graph_parents, *odb_parents;
1059                 uint32_t max_generation = 0;
1060
1061                 display_progress(progress, i + 1);
1062                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1063
1064                 graph_commit = lookup_commit(r, &cur_oid);
1065                 odb_commit = (struct commit *)create_object(r, cur_oid.hash, alloc_commit_node(r));
1066                 if (parse_commit_internal(odb_commit, 0, 0)) {
1067                         graph_report("failed to parse %s from object database",
1068                                      oid_to_hex(&cur_oid));
1069                         continue;
1070                 }
1071
1072                 if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
1073                            get_commit_tree_oid(odb_commit)))
1074                         graph_report("root tree OID for commit %s in commit-graph is %s != %s",
1075                                      oid_to_hex(&cur_oid),
1076                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
1077                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
1078
1079                 graph_parents = graph_commit->parents;
1080                 odb_parents = odb_commit->parents;
1081
1082                 while (graph_parents) {
1083                         if (odb_parents == NULL) {
1084                                 graph_report("commit-graph parent list for commit %s is too long",
1085                                              oid_to_hex(&cur_oid));
1086                                 break;
1087                         }
1088
1089                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
1090                                 graph_report("commit-graph parent for %s is %s != %s",
1091                                              oid_to_hex(&cur_oid),
1092                                              oid_to_hex(&graph_parents->item->object.oid),
1093                                              oid_to_hex(&odb_parents->item->object.oid));
1094
1095                         if (graph_parents->item->generation > max_generation)
1096                                 max_generation = graph_parents->item->generation;
1097
1098                         graph_parents = graph_parents->next;
1099                         odb_parents = odb_parents->next;
1100                 }
1101
1102                 if (odb_parents != NULL)
1103                         graph_report("commit-graph parent list for commit %s terminates early",
1104                                      oid_to_hex(&cur_oid));
1105
1106                 if (!graph_commit->generation) {
1107                         if (generation_zero == GENERATION_NUMBER_EXISTS)
1108                                 graph_report("commit-graph has generation number zero for commit %s, but non-zero elsewhere",
1109                                              oid_to_hex(&cur_oid));
1110                         generation_zero = GENERATION_ZERO_EXISTS;
1111                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
1112                         graph_report("commit-graph has non-zero generation number for commit %s, but zero elsewhere",
1113                                      oid_to_hex(&cur_oid));
1114
1115                 if (generation_zero == GENERATION_ZERO_EXISTS)
1116                         continue;
1117
1118                 /*
1119                  * If one of our parents has generation GENERATION_NUMBER_MAX, then
1120                  * our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
1121                  * extra logic in the following condition.
1122                  */
1123                 if (max_generation == GENERATION_NUMBER_MAX)
1124                         max_generation--;
1125
1126                 if (graph_commit->generation != max_generation + 1)
1127                         graph_report("commit-graph generation for commit %s is %u != %u",
1128                                      oid_to_hex(&cur_oid),
1129                                      graph_commit->generation,
1130                                      max_generation + 1);
1131
1132                 if (graph_commit->date != odb_commit->date)
1133                         graph_report("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime,
1134                                      oid_to_hex(&cur_oid),
1135                                      graph_commit->date,
1136                                      odb_commit->date);
1137         }
1138         stop_progress(&progress);
1139
1140         return verify_commit_graph_error;
1141 }
1142
1143 void free_commit_graph(struct commit_graph *g)
1144 {
1145         if (!g)
1146                 return;
1147         if (g->graph_fd >= 0) {
1148                 munmap((void *)g->data, g->data_len);
1149                 g->data = NULL;
1150                 close(g->graph_fd);
1151         }
1152         free(g);
1153 }