commit-graph.c

   1 #include "git-compat-util.h"
   2 #include "config.h"
   3 #include "lockfile.h"
   4 #include "pack.h"
   5 #include "packfile.h"
   6 #include "commit.h"
   7 #include "object.h"
   8 #include "refs.h"
   9 #include "revision.h"
  10 #include "sha1-lookup.h"
  11 #include "commit-graph.h"
  12 #include "object-store.h"
  13 #include "alloc.h"
  14 #include "hashmap.h"
  15 #include "replace-object.h"
  16 #include "progress.h"
  17 #include "bloom.h"
  18 #include "commit-slab.h"
  19 #include "shallow.h"
  20 #include "json-writer.h"
  21 #include "trace2.h"
  22
  23 void git_test_write_commit_graph_or_die(void)
  24 {
  25         int flags = 0;
  26         if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0))
  27                 return;
  28
  29         if (git_env_bool(GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS, 0))
  30                 flags = COMMIT_GRAPH_WRITE_BLOOM_FILTERS;
  31
  32         if (write_commit_graph_reachable(the_repository->objects->odb,
  33                                          flags, NULL))
  34                 die("failed to write commit-graph under GIT_TEST_COMMIT_GRAPH");
  35 }
  36
  37 #define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */
  38 #define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
  39 #define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
  40 #define GRAPH_CHUNKID_DATA 0x43444154 /* "CDAT" */
  41 #define GRAPH_CHUNKID_EXTRAEDGES 0x45444745 /* "EDGE" */
  42 #define GRAPH_CHUNKID_BLOOMINDEXES 0x42494458 /* "BIDX" */
  43 #define GRAPH_CHUNKID_BLOOMDATA 0x42444154 /* "BDAT" */
  44 #define GRAPH_CHUNKID_BASE 0x42415345 /* "BASE" */
  45 #define MAX_NUM_CHUNKS 7
  46
  47 #define GRAPH_DATA_WIDTH (the_hash_algo->rawsz + 16)
  48
  49 #define GRAPH_VERSION_1 0x1
  50 #define GRAPH_VERSION GRAPH_VERSION_1
  51
  52 #define GRAPH_EXTRA_EDGES_NEEDED 0x80000000
  53 #define GRAPH_EDGE_LAST_MASK 0x7fffffff
  54 #define GRAPH_PARENT_NONE 0x70000000
  55
  56 #define GRAPH_LAST_EDGE 0x80000000
  57
  58 #define GRAPH_HEADER_SIZE 8
  59 #define GRAPH_FANOUT_SIZE (4 * 256)
  60 #define GRAPH_CHUNKLOOKUP_WIDTH 12
  61 #define GRAPH_MIN_SIZE (GRAPH_HEADER_SIZE + 4 * GRAPH_CHUNKLOOKUP_WIDTH \
  62                         + GRAPH_FANOUT_SIZE + the_hash_algo->rawsz)
  63
  64 /* Remember to update object flag allocation in object.h */
  65 #define REACHABLE       (1u<<15)
  66
  67 /* Keep track of the order in which commits are added to our list. */
  68 define_commit_slab(commit_pos, int);
  69 static struct commit_pos commit_pos = COMMIT_SLAB_INIT(1, commit_pos);
  70
  71 static void set_commit_pos(struct repository *r, const struct object_id *oid)
  72 {
  73         static int32_t max_pos;
  74         struct commit *commit = lookup_commit(r, oid);
  75
  76         if (!commit)
  77                 return; /* should never happen, but be lenient */
  78
  79         *commit_pos_at(&commit_pos, commit) = max_pos++;
  80 }
  81
  82 static int commit_pos_cmp(const void *va, const void *vb)
  83 {
  84         const struct commit *a = *(const struct commit **)va;
  85         const struct commit *b = *(const struct commit **)vb;
  86         return commit_pos_at(&commit_pos, a) -
  87                commit_pos_at(&commit_pos, b);
  88 }
  89
  90 define_commit_slab(commit_graph_data_slab, struct commit_graph_data);
  91 static struct commit_graph_data_slab commit_graph_data_slab =
  92         COMMIT_SLAB_INIT(1, commit_graph_data_slab);
  93
  94 uint32_t commit_graph_position(const struct commit *c)
  95 {
  96         struct commit_graph_data *data =
  97                 commit_graph_data_slab_peek(&commit_graph_data_slab, c);
  98
  99         return data ? data->graph_pos : COMMIT_NOT_FROM_GRAPH;
 100 }
 101
 102 uint32_t commit_graph_generation(const struct commit *c)
 103 {
 104         struct commit_graph_data *data =
 105                 commit_graph_data_slab_peek(&commit_graph_data_slab, c);
 106
 107         if (!data)
 108                 return GENERATION_NUMBER_INFINITY;
 109         else if (data->graph_pos == COMMIT_NOT_FROM_GRAPH)
 110                 return GENERATION_NUMBER_INFINITY;
 111
 112         return data->generation;
 113 }
 114
 115 static struct commit_graph_data *commit_graph_data_at(const struct commit *c)
 116 {
 117         unsigned int i, nth_slab;
 118         struct commit_graph_data *data =
 119                 commit_graph_data_slab_peek(&commit_graph_data_slab, c);
 120
 121         if (data)
 122                 return data;
 123
 124         nth_slab = c->index / commit_graph_data_slab.slab_size;
 125         data = commit_graph_data_slab_at(&commit_graph_data_slab, c);
 126
 127         /*
 128          * commit-slab initializes elements with zero, overwrite this with
 129          * COMMIT_NOT_FROM_GRAPH for graph_pos.
 130          *
 131          * We avoid initializing generation with checking if graph position
 132          * is not COMMIT_NOT_FROM_GRAPH.
 133          */
 134         for (i = 0; i < commit_graph_data_slab.slab_size; i++) {
 135                 commit_graph_data_slab.slab[nth_slab][i].graph_pos =
 136                         COMMIT_NOT_FROM_GRAPH;
 137         }
 138
 139         return data;
 140 }
 141
 142 static int commit_gen_cmp(const void *va, const void *vb)
 143 {
 144         const struct commit *a = *(const struct commit **)va;
 145         const struct commit *b = *(const struct commit **)vb;
 146
 147         uint32_t generation_a = commit_graph_generation(a);
 148         uint32_t generation_b = commit_graph_generation(b);
 149         /* lower generation commits first */
 150         if (generation_a < generation_b)
 151                 return -1;
 152         else if (generation_a > generation_b)
 153                 return 1;
 154
 155         /* use date as a heuristic when generations are equal */
 156         if (a->date < b->date)
 157                 return -1;
 158         else if (a->date > b->date)
 159                 return 1;
 160         return 0;
 161 }
 162
 163 char *get_commit_graph_filename(struct object_directory *obj_dir)
 164 {
 165         return xstrfmt("%s/info/commit-graph", obj_dir->path);
 166 }
 167
 168 static char *get_split_graph_filename(struct object_directory *odb,
 169                                       const char *oid_hex)
 170 {
 171         return xstrfmt("%s/info/commit-graphs/graph-%s.graph", odb->path,
 172                        oid_hex);
 173 }
 174
 175 char *get_commit_graph_chain_filename(struct object_directory *odb)
 176 {
 177         return xstrfmt("%s/info/commit-graphs/commit-graph-chain", odb->path);
 178 }
 179
 180 static uint8_t oid_version(void)
 181 {
 182         switch (hash_algo_by_ptr(the_hash_algo)) {
 183         case GIT_HASH_SHA1:
 184                 return 1;
 185         case GIT_HASH_SHA256:
 186                 return 2;
 187         default:
 188                 die(_("invalid hash version"));
 189         }
 190 }
 191
 192 static struct commit_graph *alloc_commit_graph(void)
 193 {
 194         struct commit_graph *g = xcalloc(1, sizeof(*g));
 195
 196         return g;
 197 }
 198
 199 extern int read_replace_refs;
 200
 201 static int commit_graph_compatible(struct repository *r)
 202 {
 203         if (!r->gitdir)
 204                 return 0;
 205
 206         if (read_replace_refs) {
 207                 prepare_replace_object(r);
 208                 if (hashmap_get_size(&r->objects->replace_map->map))
 209                         return 0;
 210         }
 211
 212         prepare_commit_graft(r);
 213         if (r->parsed_objects &&
 214             (r->parsed_objects->grafts_nr || r->parsed_objects->substituted_parent))
 215                 return 0;
 216         if (is_repository_shallow(r))
 217                 return 0;
 218
 219         return 1;
 220 }
 221
 222 int open_commit_graph(const char *graph_file, int *fd, struct stat *st)
 223 {
 224         *fd = git_open(graph_file);
 225         if (*fd < 0)
 226                 return 0;
 227         if (fstat(*fd, st)) {
 228                 close(*fd);
 229                 return 0;
 230         }
 231         return 1;
 232 }
 233
 234 struct commit_graph *load_commit_graph_one_fd_st(struct repository *r,
 235                                                  int fd, struct stat *st,
 236                                                  struct object_directory *odb)
 237 {
 238         void *graph_map;
 239         size_t graph_size;
 240         struct commit_graph *ret;
 241
 242         graph_size = xsize_t(st->st_size);
 243
 244         if (graph_size < GRAPH_MIN_SIZE) {
 245                 close(fd);
 246                 error(_("commit-graph file is too small"));
 247                 return NULL;
 248         }
 249         graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
 250         close(fd);
 251         ret = parse_commit_graph(r, graph_map, graph_size);
 252
 253         if (ret)
 254                 ret->odb = odb;
 255         else
 256                 munmap(graph_map, graph_size);
 257
 258         return ret;
 259 }
 260
 261 static int verify_commit_graph_lite(struct commit_graph *g)
 262 {
 263         /*
 264          * Basic validation shared between parse_commit_graph()
 265          * which'll be called every time the graph is used, and the
 266          * much more expensive verify_commit_graph() used by
 267          * "commit-graph verify".
 268          *
 269          * There should only be very basic checks here to ensure that
 270          * we don't e.g. segfault in fill_commit_in_graph(), but
 271          * because this is a very hot codepath nothing that e.g. loops
 272          * over g->num_commits, or runs a checksum on the commit-graph
 273          * itself.
 274          */
 275         if (!g->chunk_oid_fanout) {
 276                 error("commit-graph is missing the OID Fanout chunk");
 277                 return 1;
 278         }
 279         if (!g->chunk_oid_lookup) {
 280                 error("commit-graph is missing the OID Lookup chunk");
 281                 return 1;
 282         }
 283         if (!g->chunk_commit_data) {
 284                 error("commit-graph is missing the Commit Data chunk");
 285                 return 1;
 286         }
 287
 288         return 0;
 289 }
 290
 291 struct commit_graph *parse_commit_graph(struct repository *r,
 292                                         void *graph_map, size_t graph_size)
 293 {
 294         const unsigned char *data, *chunk_lookup;
 295         uint32_t i;
 296         struct commit_graph *graph;
 297         uint64_t next_chunk_offset;
 298         uint32_t graph_signature;
 299         unsigned char graph_version, hash_version;
 300
 301         if (!graph_map)
 302                 return NULL;
 303
 304         if (graph_size < GRAPH_MIN_SIZE)
 305                 return NULL;
 306
 307         data = (const unsigned char *)graph_map;
 308
 309         graph_signature = get_be32(data);
 310         if (graph_signature != GRAPH_SIGNATURE) {
 311                 error(_("commit-graph signature %X does not match signature %X"),
 312                       graph_signature, GRAPH_SIGNATURE);
 313                 return NULL;
 314         }
 315
 316         graph_version = *(unsigned char*)(data + 4);
 317         if (graph_version != GRAPH_VERSION) {
 318                 error(_("commit-graph version %X does not match version %X"),
 319                       graph_version, GRAPH_VERSION);
 320                 return NULL;
 321         }
 322
 323         hash_version = *(unsigned char*)(data + 5);
 324         if (hash_version != oid_version()) {
 325                 error(_("commit-graph hash version %X does not match version %X"),
 326                       hash_version, oid_version());
 327                 return NULL;
 328         }
 329
 330         prepare_repo_settings(r);
 331
 332         graph = alloc_commit_graph();
 333
 334         graph->hash_len = the_hash_algo->rawsz;
 335         graph->num_chunks = *(unsigned char*)(data + 6);
 336         graph->data = graph_map;
 337         graph->data_len = graph_size;
 338
 339         if (graph_size < GRAPH_HEADER_SIZE +
 340                          (graph->num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH +
 341                          GRAPH_FANOUT_SIZE + the_hash_algo->rawsz) {
 342                 error(_("commit-graph file is too small to hold %u chunks"),
 343                       graph->num_chunks);
 344                 free(graph);
 345                 return NULL;
 346         }
 347
 348         chunk_lookup = data + 8;
 349         next_chunk_offset = get_be64(chunk_lookup + 4);
 350         for (i = 0; i < graph->num_chunks; i++) {
 351                 uint32_t chunk_id;
 352                 uint64_t chunk_offset = next_chunk_offset;
 353                 int chunk_repeated = 0;
 354
 355                 chunk_id = get_be32(chunk_lookup + 0);
 356
 357                 chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
 358                 next_chunk_offset = get_be64(chunk_lookup + 4);
 359
 360                 if (chunk_offset > graph_size - the_hash_algo->rawsz) {
 361                         error(_("commit-graph improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
 362                               (uint32_t)chunk_offset);
 363                         goto free_and_return;
 364                 }
 365
 366                 switch (chunk_id) {
 367                 case GRAPH_CHUNKID_OIDFANOUT:
 368                         if (graph->chunk_oid_fanout)
 369                                 chunk_repeated = 1;
 370                         else
 371                                 graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
 372                         break;
 373
 374                 case GRAPH_CHUNKID_OIDLOOKUP:
 375                         if (graph->chunk_oid_lookup)
 376                                 chunk_repeated = 1;
 377                         else {
 378                                 graph->chunk_oid_lookup = data + chunk_offset;
 379                                 graph->num_commits = (next_chunk_offset - chunk_offset)
 380                                                      / graph->hash_len;
 381                         }
 382                         break;
 383
 384                 case GRAPH_CHUNKID_DATA:
 385                         if (graph->chunk_commit_data)
 386                                 chunk_repeated = 1;
 387                         else
 388                                 graph->chunk_commit_data = data + chunk_offset;
 389                         break;
 390
 391                 case GRAPH_CHUNKID_EXTRAEDGES:
 392                         if (graph->chunk_extra_edges)
 393                                 chunk_repeated = 1;
 394                         else
 395                                 graph->chunk_extra_edges = data + chunk_offset;
 396                         break;
 397
 398                 case GRAPH_CHUNKID_BASE:
 399                         if (graph->chunk_base_graphs)
 400                                 chunk_repeated = 1;
 401                         else
 402                                 graph->chunk_base_graphs = data + chunk_offset;
 403                         break;
 404
 405                 case GRAPH_CHUNKID_BLOOMINDEXES:
 406                         if (graph->chunk_bloom_indexes)
 407                                 chunk_repeated = 1;
 408                         else if (r->settings.commit_graph_read_changed_paths)
 409                                 graph->chunk_bloom_indexes = data + chunk_offset;
 410                         break;
 411
 412                 case GRAPH_CHUNKID_BLOOMDATA:
 413                         if (graph->chunk_bloom_data)
 414                                 chunk_repeated = 1;
 415                         else if (r->settings.commit_graph_read_changed_paths) {
 416                                 uint32_t hash_version;
 417                                 graph->chunk_bloom_data = data + chunk_offset;
 418                                 hash_version = get_be32(data + chunk_offset);
 419
 420                                 if (hash_version != 1)
 421                                         break;
 422
 423                                 graph->bloom_filter_settings = xmalloc(sizeof(struct bloom_filter_settings));
 424                                 graph->bloom_filter_settings->hash_version = hash_version;
 425                                 graph->bloom_filter_settings->num_hashes = get_be32(data + chunk_offset + 4);
 426                                 graph->bloom_filter_settings->bits_per_entry = get_be32(data + chunk_offset + 8);
 427                                 graph->bloom_filter_settings->max_changed_paths = DEFAULT_BLOOM_MAX_CHANGES;
 428                         }
 429                         break;
 430                 }
 431
 432                 if (chunk_repeated) {
 433                         error(_("commit-graph chunk id %08x appears multiple times"), chunk_id);
 434                         goto free_and_return;
 435                 }
 436         }
 437
 438         if (graph->chunk_bloom_indexes && graph->chunk_bloom_data) {
 439                 init_bloom_filters();
 440         } else {
 441                 /* We need both the bloom chunks to exist together. Else ignore the data */
 442                 graph->chunk_bloom_indexes = NULL;
 443                 graph->chunk_bloom_data = NULL;
 444                 FREE_AND_NULL(graph->bloom_filter_settings);
 445         }
 446
 447         hashcpy(graph->oid.hash, graph->data + graph->data_len - graph->hash_len);
 448
 449         if (verify_commit_graph_lite(graph))
 450                 goto free_and_return;
 451
 452         return graph;
 453
 454 free_and_return:
 455         free(graph->bloom_filter_settings);
 456         free(graph);
 457         return NULL;
 458 }
 459
 460 static struct commit_graph *load_commit_graph_one(struct repository *r,
 461                                                   const char *graph_file,
 462                                                   struct object_directory *odb)
 463 {
 464
 465         struct stat st;
 466         int fd;
 467         struct commit_graph *g;
 468         int open_ok = open_commit_graph(graph_file, &fd, &st);
 469
 470         if (!open_ok)
 471                 return NULL;
 472
 473         g = load_commit_graph_one_fd_st(r, fd, &st, odb);
 474
 475         if (g)
 476                 g->filename = xstrdup(graph_file);
 477
 478         return g;
 479 }
 480
 481 static struct commit_graph *load_commit_graph_v1(struct repository *r,
 482                                                  struct object_directory *odb)
 483 {
 484         char *graph_name = get_commit_graph_filename(odb);
 485         struct commit_graph *g = load_commit_graph_one(r, graph_name, odb);
 486         free(graph_name);
 487
 488         return g;
 489 }
 490
 491 static int add_graph_to_chain(struct commit_graph *g,
 492                               struct commit_graph *chain,
 493                               struct object_id *oids,
 494                               int n)
 495 {
 496         struct commit_graph *cur_g = chain;
 497
 498         if (n && !g->chunk_base_graphs) {
 499                 warning(_("commit-graph has no base graphs chunk"));
 500                 return 0;
 501         }
 502
 503         while (n) {
 504                 n--;
 505
 506                 if (!cur_g ||
 507                     !oideq(&oids[n], &cur_g->oid) ||
 508                     !hasheq(oids[n].hash, g->chunk_base_graphs + g->hash_len * n)) {
 509                         warning(_("commit-graph chain does not match"));
 510                         return 0;
 511                 }
 512
 513                 cur_g = cur_g->base_graph;
 514         }
 515
 516         g->base_graph = chain;
 517
 518         if (chain)
 519                 g->num_commits_in_base = chain->num_commits + chain->num_commits_in_base;
 520
 521         return 1;
 522 }
 523
 524 static struct commit_graph *load_commit_graph_chain(struct repository *r,
 525                                                     struct object_directory *odb)
 526 {
 527         struct commit_graph *graph_chain = NULL;
 528         struct strbuf line = STRBUF_INIT;
 529         struct stat st;
 530         struct object_id *oids;
 531         int i = 0, valid = 1, count;
 532         char *chain_name = get_commit_graph_chain_filename(odb);
 533         FILE *fp;
 534         int stat_res;
 535
 536         fp = fopen(chain_name, "r");
 537         stat_res = stat(chain_name, &st);
 538         free(chain_name);
 539
 540         if (!fp ||
 541             stat_res ||
 542             st.st_size <= the_hash_algo->hexsz)
 543                 return NULL;
 544
 545         count = st.st_size / (the_hash_algo->hexsz + 1);
 546         oids = xcalloc(count, sizeof(struct object_id));
 547
 548         prepare_alt_odb(r);
 549
 550         for (i = 0; i < count; i++) {
 551                 struct object_directory *odb;
 552
 553                 if (strbuf_getline_lf(&line, fp) == EOF)
 554                         break;
 555
 556                 if (get_oid_hex(line.buf, &oids[i])) {
 557                         warning(_("invalid commit-graph chain: line '%s' not a hash"),
 558                                 line.buf);
 559                         valid = 0;
 560                         break;
 561                 }
 562
 563                 valid = 0;
 564                 for (odb = r->objects->odb; odb; odb = odb->next) {
 565                         char *graph_name = get_split_graph_filename(odb, line.buf);
 566                         struct commit_graph *g = load_commit_graph_one(r, graph_name, odb);
 567
 568                         free(graph_name);
 569
 570                         if (g) {
 571                                 if (add_graph_to_chain(g, graph_chain, oids, i)) {
 572                                         graph_chain = g;
 573                                         valid = 1;
 574                                 }
 575
 576                                 break;
 577                         }
 578                 }
 579
 580                 if (!valid) {
 581                         warning(_("unable to find all commit-graph files"));
 582                         break;
 583                 }
 584         }
 585
 586         free(oids);
 587         fclose(fp);
 588         strbuf_release(&line);
 589
 590         return graph_chain;
 591 }
 592
 593 struct commit_graph *read_commit_graph_one(struct repository *r,
 594                                            struct object_directory *odb)
 595 {
 596         struct commit_graph *g = load_commit_graph_v1(r, odb);
 597
 598         if (!g)
 599                 g = load_commit_graph_chain(r, odb);
 600
 601         return g;
 602 }
 603
 604 static void prepare_commit_graph_one(struct repository *r,
 605                                      struct object_directory *odb)
 606 {
 607
 608         if (r->objects->commit_graph)
 609                 return;
 610
 611         r->objects->commit_graph = read_commit_graph_one(r, odb);
 612 }
 613
 614 /*
 615  * Return 1 if commit_graph is non-NULL, and 0 otherwise.
 616  *
 617  * On the first invocation, this function attempts to load the commit
 618  * graph if the_repository is configured to have one.
 619  */
 620 static int prepare_commit_graph(struct repository *r)
 621 {
 622         struct object_directory *odb;
 623
 624         /*
 625          * This must come before the "already attempted?" check below, because
 626          * we want to disable even an already-loaded graph file.
 627          */
 628         if (r->commit_graph_disabled)
 629                 return 0;
 630
 631         if (r->objects->commit_graph_attempted)
 632                 return !!r->objects->commit_graph;
 633         r->objects->commit_graph_attempted = 1;
 634
 635         prepare_repo_settings(r);
 636
 637         if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
 638             r->settings.core_commit_graph != 1)
 639                 /*
 640                  * This repository is not configured to use commit graphs, so
 641                  * do not load one. (But report commit_graph_attempted anyway
 642                  * so that commit graph loading is not attempted again for this
 643                  * repository.)
 644                  */
 645                 return 0;
 646
 647         if (!commit_graph_compatible(r))
 648                 return 0;
 649
 650         prepare_alt_odb(r);
 651         for (odb = r->objects->odb;
 652              !r->objects->commit_graph && odb;
 653              odb = odb->next)
 654                 prepare_commit_graph_one(r, odb);
 655         return !!r->objects->commit_graph;
 656 }
 657
 658 int generation_numbers_enabled(struct repository *r)
 659 {
 660         uint32_t first_generation;
 661         struct commit_graph *g;
 662         if (!prepare_commit_graph(r))
 663                return 0;
 664
 665         g = r->objects->commit_graph;
 666
 667         if (!g->num_commits)
 668                 return 0;
 669
 670         first_generation = get_be32(g->chunk_commit_data +
 671                                     g->hash_len + 8) >> 2;
 672
 673         return !!first_generation;
 674 }
 675
 676 struct bloom_filter_settings *get_bloom_filter_settings(struct repository *r)
 677 {
 678         struct commit_graph *g = r->objects->commit_graph;
 679         while (g) {
 680                 if (g->bloom_filter_settings)
 681                         return g->bloom_filter_settings;
 682                 g = g->base_graph;
 683         }
 684         return NULL;
 685 }
 686
 687 static void close_commit_graph_one(struct commit_graph *g)
 688 {
 689         if (!g)
 690                 return;
 691
 692         close_commit_graph_one(g->base_graph);
 693         free_commit_graph(g);
 694 }
 695
 696 void close_commit_graph(struct raw_object_store *o)
 697 {
 698         close_commit_graph_one(o->commit_graph);
 699         o->commit_graph = NULL;
 700 }
 701
 702 static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
 703 {
 704         return bsearch_hash(oid->hash, g->chunk_oid_fanout,
 705                             g->chunk_oid_lookup, g->hash_len, pos);
 706 }
 707
 708 static void load_oid_from_graph(struct commit_graph *g,
 709                                 uint32_t pos,
 710                                 struct object_id *oid)
 711 {
 712         uint32_t lex_index;
 713
 714         while (g && pos < g->num_commits_in_base)
 715                 g = g->base_graph;
 716
 717         if (!g)
 718                 BUG("NULL commit-graph");
 719
 720         if (pos >= g->num_commits + g->num_commits_in_base)
 721                 die(_("invalid commit position. commit-graph is likely corrupt"));
 722
 723         lex_index = pos - g->num_commits_in_base;
 724
 725         hashcpy(oid->hash, g->chunk_oid_lookup + g->hash_len * lex_index);
 726 }
 727
 728 static struct commit_list **insert_parent_or_die(struct repository *r,
 729                                                  struct commit_graph *g,
 730                                                  uint32_t pos,
 731                                                  struct commit_list **pptr)
 732 {
 733         struct commit *c;
 734         struct object_id oid;
 735
 736         if (pos >= g->num_commits + g->num_commits_in_base)
 737                 die("invalid parent position %"PRIu32, pos);
 738
 739         load_oid_from_graph(g, pos, &oid);
 740         c = lookup_commit(r, &oid);
 741         if (!c)
 742                 die(_("could not find commit %s"), oid_to_hex(&oid));
 743         commit_graph_data_at(c)->graph_pos = pos;
 744         return &commit_list_insert(c, pptr)->next;
 745 }
 746
 747 static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
 748 {
 749         const unsigned char *commit_data;
 750         struct commit_graph_data *graph_data;
 751         uint32_t lex_index;
 752
 753         while (pos < g->num_commits_in_base)
 754                 g = g->base_graph;
 755
 756         lex_index = pos - g->num_commits_in_base;
 757         commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * lex_index;
 758
 759         graph_data = commit_graph_data_at(item);
 760         graph_data->graph_pos = pos;
 761         graph_data->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 762 }
 763
 764 static inline void set_commit_tree(struct commit *c, struct tree *t)
 765 {
 766         c->maybe_tree = t;
 767 }
 768
 769 static int fill_commit_in_graph(struct repository *r,
 770                                 struct commit *item,
 771                                 struct commit_graph *g, uint32_t pos)
 772 {
 773         uint32_t edge_value;
 774         uint32_t *parent_data_ptr;
 775         uint64_t date_low, date_high;
 776         struct commit_list **pptr;
 777         struct commit_graph_data *graph_data;
 778         const unsigned char *commit_data;
 779         uint32_t lex_index;
 780
 781         while (pos < g->num_commits_in_base)
 782                 g = g->base_graph;
 783
 784         if (pos >= g->num_commits + g->num_commits_in_base)
 785                 die(_("invalid commit position. commit-graph is likely corrupt"));
 786
 787         /*
 788          * Store the "full" position, but then use the
 789          * "local" position for the rest of the calculation.
 790          */
 791         graph_data = commit_graph_data_at(item);
 792         graph_data->graph_pos = pos;
 793         lex_index = pos - g->num_commits_in_base;
 794
 795         commit_data = g->chunk_commit_data + (g->hash_len + 16) * lex_index;
 796
 797         item->object.parsed = 1;
 798
 799         set_commit_tree(item, NULL);
 800
 801         date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
 802         date_low = get_be32(commit_data + g->hash_len + 12);
 803         item->date = (timestamp_t)((date_high << 32) | date_low);
 804
 805         graph_data->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
 806
 807         pptr = &item->parents;
 808
 809         edge_value = get_be32(commit_data + g->hash_len);
 810         if (edge_value == GRAPH_PARENT_NONE)
 811                 return 1;
 812         pptr = insert_parent_or_die(r, g, edge_value, pptr);
 813
 814         edge_value = get_be32(commit_data + g->hash_len + 4);
 815         if (edge_value == GRAPH_PARENT_NONE)
 816                 return 1;
 817         if (!(edge_value & GRAPH_EXTRA_EDGES_NEEDED)) {
 818                 pptr = insert_parent_or_die(r, g, edge_value, pptr);
 819                 return 1;
 820         }
 821
 822         parent_data_ptr = (uint32_t*)(g->chunk_extra_edges +
 823                           4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
 824         do {
 825                 edge_value = get_be32(parent_data_ptr);
 826                 pptr = insert_parent_or_die(r, g,
 827                                             edge_value & GRAPH_EDGE_LAST_MASK,
 828                                             pptr);
 829                 parent_data_ptr++;
 830         } while (!(edge_value & GRAPH_LAST_EDGE));
 831
 832         return 1;
 833 }
 834
 835 static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 836 {
 837         uint32_t graph_pos = commit_graph_position(item);
 838         if (graph_pos != COMMIT_NOT_FROM_GRAPH) {
 839                 *pos = graph_pos;
 840                 return 1;
 841         } else {
 842                 struct commit_graph *cur_g = g;
 843                 uint32_t lex_index;
 844
 845                 while (cur_g && !bsearch_graph(cur_g, &(item->object.oid), &lex_index))
 846                         cur_g = cur_g->base_graph;
 847
 848                 if (cur_g) {
 849                         *pos = lex_index + cur_g->num_commits_in_base;
 850                         return 1;
 851                 }
 852
 853                 return 0;
 854         }
 855 }
 856
 857 static int parse_commit_in_graph_one(struct repository *r,
 858                                      struct commit_graph *g,
 859                                      struct commit *item)
 860 {
 861         uint32_t pos;
 862
 863         if (item->object.parsed)
 864                 return 1;
 865
 866         if (find_commit_in_graph(item, g, &pos))
 867                 return fill_commit_in_graph(r, item, g, pos);
 868
 869         return 0;
 870 }
 871
 872 int parse_commit_in_graph(struct repository *r, struct commit *item)
 873 {
 874         static int checked_env = 0;
 875
 876         if (!checked_env &&
 877             git_env_bool(GIT_TEST_COMMIT_GRAPH_DIE_ON_PARSE, 0))
 878                 die("dying as requested by the '%s' variable on commit-graph parse!",
 879                     GIT_TEST_COMMIT_GRAPH_DIE_ON_PARSE);
 880         checked_env = 1;
 881
 882         if (!prepare_commit_graph(r))
 883                 return 0;
 884         return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
 885 }
 886
 887 void load_commit_graph_info(struct repository *r, struct commit *item)
 888 {
 889         uint32_t pos;
 890         if (!prepare_commit_graph(r))
 891                 return;
 892         if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
 893                 fill_commit_graph_info(item, r->objects->commit_graph, pos);
 894 }
 895
 896 static struct tree *load_tree_for_commit(struct repository *r,
 897                                          struct commit_graph *g,
 898                                          struct commit *c)
 899 {
 900         struct object_id oid;
 901         const unsigned char *commit_data;
 902         uint32_t graph_pos = commit_graph_position(c);
 903
 904         while (graph_pos < g->num_commits_in_base)
 905                 g = g->base_graph;
 906
 907         commit_data = g->chunk_commit_data +
 908                         GRAPH_DATA_WIDTH * (graph_pos - g->num_commits_in_base);
 909
 910         hashcpy(oid.hash, commit_data);
 911         set_commit_tree(c, lookup_tree(r, &oid));
 912
 913         return c->maybe_tree;
 914 }
 915
 916 static struct tree *get_commit_tree_in_graph_one(struct repository *r,
 917                                                  struct commit_graph *g,
 918                                                  const struct commit *c)
 919 {
 920         if (c->maybe_tree)
 921                 return c->maybe_tree;
 922         if (commit_graph_position(c) == COMMIT_NOT_FROM_GRAPH)
 923                 BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
 924
 925         return load_tree_for_commit(r, g, (struct commit *)c);
 926 }
 927
 928 struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
 929 {
 930         return get_commit_tree_in_graph_one(r, r->objects->commit_graph, c);
 931 }
 932
 933 struct packed_commit_list {
 934         struct commit **list;
 935         size_t nr;
 936         size_t alloc;
 937 };
 938
 939 struct write_commit_graph_context {
 940         struct repository *r;
 941         struct object_directory *odb;
 942         char *graph_name;
 943         struct oid_array oids;
 944         struct packed_commit_list commits;
 945         int num_extra_edges;
 946         unsigned long approx_nr_objects;
 947         struct progress *progress;
 948         int progress_done;
 949         uint64_t progress_cnt;
 950
 951         char *base_graph_name;
 952         int num_commit_graphs_before;
 953         int num_commit_graphs_after;
 954         char **commit_graph_filenames_before;
 955         char **commit_graph_filenames_after;
 956         char **commit_graph_hash_after;
 957         uint32_t new_num_commits_in_base;
 958         struct commit_graph *new_base_graph;
 959
 960         unsigned append:1,
 961                  report_progress:1,
 962                  split:1,
 963                  changed_paths:1,
 964                  order_by_pack:1;
 965
 966         const struct commit_graph_opts *opts;
 967         size_t total_bloom_filter_data_size;
 968         const struct bloom_filter_settings *bloom_settings;
 969
 970         int count_bloom_filter_computed;
 971         int count_bloom_filter_not_computed;
 972         int count_bloom_filter_trunc_empty;
 973         int count_bloom_filter_trunc_large;
 974 };
 975
 976 static int write_graph_chunk_fanout(struct hashfile *f,
 977                                     struct write_commit_graph_context *ctx)
 978 {
 979         int i, count = 0;
 980         struct commit **list = ctx->commits.list;
 981
 982         /*
 983          * Write the first-level table (the list is sorted,
 984          * but we use a 256-entry lookup to be able to avoid
 985          * having to do eight extra binary search iterations).
 986          */
 987         for (i = 0; i < 256; i++) {
 988                 while (count < ctx->commits.nr) {
 989                         if ((*list)->object.oid.hash[0] != i)
 990                                 break;
 991                         display_progress(ctx->progress, ++ctx->progress_cnt);
 992                         count++;
 993                         list++;
 994                 }
 995
 996                 hashwrite_be32(f, count);
 997         }
 998
 999         return 0;
1000 }
1001
1002 static int write_graph_chunk_oids(struct hashfile *f,
1003                                   struct write_commit_graph_context *ctx)
1004 {
1005         struct commit **list = ctx->commits.list;
1006         int count;
1007         for (count = 0; count < ctx->commits.nr; count++, list++) {
1008                 display_progress(ctx->progress, ++ctx->progress_cnt);
1009                 hashwrite(f, (*list)->object.oid.hash, the_hash_algo->rawsz);
1010         }
1011
1012         return 0;
1013 }
1014
1015 static const unsigned char *commit_to_sha1(size_t index, void *table)
1016 {
1017         struct commit **commits = table;
1018         return commits[index]->object.oid.hash;
1019 }
1020
1021 static int write_graph_chunk_data(struct hashfile *f,
1022                                   struct write_commit_graph_context *ctx)
1023 {
1024         struct commit **list = ctx->commits.list;
1025         struct commit **last = ctx->commits.list + ctx->commits.nr;
1026         uint32_t num_extra_edges = 0;
1027
1028         while (list < last) {
1029                 struct commit_list *parent;
1030                 struct object_id *tree;
1031                 int edge_value;
1032                 uint32_t packedDate[2];
1033                 display_progress(ctx->progress, ++ctx->progress_cnt);
1034
1035                 if (parse_commit_no_graph(*list))
1036                         die(_("unable to parse commit %s"),
1037                                 oid_to_hex(&(*list)->object.oid));
1038                 tree = get_commit_tree_oid(*list);
1039                 hashwrite(f, tree->hash, the_hash_algo->rawsz);
1040
1041                 parent = (*list)->parents;
1042
1043                 if (!parent)
1044                         edge_value = GRAPH_PARENT_NONE;
1045                 else {
1046                         edge_value = sha1_pos(parent->item->object.oid.hash,
1047                                               ctx->commits.list,
1048                                               ctx->commits.nr,
1049                                               commit_to_sha1);
1050
1051                         if (edge_value >= 0)
1052                                 edge_value += ctx->new_num_commits_in_base;
1053                         else if (ctx->new_base_graph) {
1054                                 uint32_t pos;
1055                                 if (find_commit_in_graph(parent->item,
1056                                                          ctx->new_base_graph,
1057                                                          &pos))
1058                                         edge_value = pos;
1059                         }
1060
1061                         if (edge_value < 0)
1062                                 BUG("missing parent %s for commit %s",
1063                                     oid_to_hex(&parent->item->object.oid),
1064                                     oid_to_hex(&(*list)->object.oid));
1065                 }
1066
1067                 hashwrite_be32(f, edge_value);
1068
1069                 if (parent)
1070                         parent = parent->next;
1071
1072                 if (!parent)
1073                         edge_value = GRAPH_PARENT_NONE;
1074                 else if (parent->next)
1075                         edge_value = GRAPH_EXTRA_EDGES_NEEDED | num_extra_edges;
1076                 else {
1077                         edge_value = sha1_pos(parent->item->object.oid.hash,
1078                                               ctx->commits.list,
1079                                               ctx->commits.nr,
1080                                               commit_to_sha1);
1081
1082                         if (edge_value >= 0)
1083                                 edge_value += ctx->new_num_commits_in_base;
1084                         else if (ctx->new_base_graph) {
1085                                 uint32_t pos;
1086                                 if (find_commit_in_graph(parent->item,
1087                                                          ctx->new_base_graph,
1088                                                          &pos))
1089                                         edge_value = pos;
1090                         }
1091
1092                         if (edge_value < 0)
1093                                 BUG("missing parent %s for commit %s",
1094                                     oid_to_hex(&parent->item->object.oid),
1095                                     oid_to_hex(&(*list)->object.oid));
1096                 }
1097
1098                 hashwrite_be32(f, edge_value);
1099
1100                 if (edge_value & GRAPH_EXTRA_EDGES_NEEDED) {
1101                         do {
1102                                 num_extra_edges++;
1103                                 parent = parent->next;
1104                         } while (parent);
1105                 }
1106
1107                 if (sizeof((*list)->date) > 4)
1108                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
1109                 else
1110                         packedDate[0] = 0;
1111
1112                 packedDate[0] |= htonl(commit_graph_data_at(*list)->generation << 2);
1113
1114                 packedDate[1] = htonl((*list)->date);
1115                 hashwrite(f, packedDate, 8);
1116
1117                 list++;
1118         }
1119
1120         return 0;
1121 }
1122
1123 static int write_graph_chunk_extra_edges(struct hashfile *f,
1124                                          struct write_commit_graph_context *ctx)
1125 {
1126         struct commit **list = ctx->commits.list;
1127         struct commit **last = ctx->commits.list + ctx->commits.nr;
1128         struct commit_list *parent;
1129
1130         while (list < last) {
1131                 int num_parents = 0;
1132
1133                 display_progress(ctx->progress, ++ctx->progress_cnt);
1134
1135                 for (parent = (*list)->parents; num_parents < 3 && parent;
1136                      parent = parent->next)
1137                         num_parents++;
1138
1139                 if (num_parents <= 2) {
1140                         list++;
1141                         continue;
1142                 }
1143
1144                 /* Since num_parents > 2, this initializer is safe. */
1145                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
1146                         int edge_value = sha1_pos(parent->item->object.oid.hash,
1147                                                   ctx->commits.list,
1148                                                   ctx->commits.nr,
1149                                                   commit_to_sha1);
1150
1151                         if (edge_value >= 0)
1152                                 edge_value += ctx->new_num_commits_in_base;
1153                         else if (ctx->new_base_graph) {
1154                                 uint32_t pos;
1155                                 if (find_commit_in_graph(parent->item,
1156                                                          ctx->new_base_graph,
1157                                                          &pos))
1158                                         edge_value = pos;
1159                         }
1160
1161                         if (edge_value < 0)
1162                                 BUG("missing parent %s for commit %s",
1163                                     oid_to_hex(&parent->item->object.oid),
1164                                     oid_to_hex(&(*list)->object.oid));
1165                         else if (!parent->next)
1166                                 edge_value |= GRAPH_LAST_EDGE;
1167
1168                         hashwrite_be32(f, edge_value);
1169                 }
1170
1171                 list++;
1172         }
1173
1174         return 0;
1175 }
1176
1177 static int write_graph_chunk_bloom_indexes(struct hashfile *f,
1178                                            struct write_commit_graph_context *ctx)
1179 {
1180         struct commit **list = ctx->commits.list;
1181         struct commit **last = ctx->commits.list + ctx->commits.nr;
1182         uint32_t cur_pos = 0;
1183
1184         while (list < last) {
1185                 struct bloom_filter *filter = get_bloom_filter(ctx->r, *list);
1186                 size_t len = filter ? filter->len : 0;
1187                 cur_pos += len;
1188                 display_progress(ctx->progress, ++ctx->progress_cnt);
1189                 hashwrite_be32(f, cur_pos);
1190                 list++;
1191         }
1192
1193         return 0;
1194 }
1195
1196 static void trace2_bloom_filter_settings(struct write_commit_graph_context *ctx)
1197 {
1198         struct json_writer jw = JSON_WRITER_INIT;
1199
1200         jw_object_begin(&jw, 0);
1201         jw_object_intmax(&jw, "hash_version", ctx->bloom_settings->hash_version);
1202         jw_object_intmax(&jw, "num_hashes", ctx->bloom_settings->num_hashes);
1203         jw_object_intmax(&jw, "bits_per_entry", ctx->bloom_settings->bits_per_entry);
1204         jw_object_intmax(&jw, "max_changed_paths", ctx->bloom_settings->max_changed_paths);
1205         jw_end(&jw);
1206
1207         trace2_data_json("bloom", ctx->r, "settings", &jw);
1208
1209         jw_release(&jw);
1210 }
1211
1212 static int write_graph_chunk_bloom_data(struct hashfile *f,
1213                                         struct write_commit_graph_context *ctx)
1214 {
1215         struct commit **list = ctx->commits.list;
1216         struct commit **last = ctx->commits.list + ctx->commits.nr;
1217
1218         trace2_bloom_filter_settings(ctx);
1219
1220         hashwrite_be32(f, ctx->bloom_settings->hash_version);
1221         hashwrite_be32(f, ctx->bloom_settings->num_hashes);
1222         hashwrite_be32(f, ctx->bloom_settings->bits_per_entry);
1223
1224         while (list < last) {
1225                 struct bloom_filter *filter = get_bloom_filter(ctx->r, *list);
1226                 size_t len = filter ? filter->len : 0;
1227
1228                 display_progress(ctx->progress, ++ctx->progress_cnt);
1229                 if (len)
1230                         hashwrite(f, filter->data, len * sizeof(unsigned char));
1231                 list++;
1232         }
1233
1234         return 0;
1235 }
1236
1237 static int add_packed_commits(const struct object_id *oid,
1238                               struct packed_git *pack,
1239                               uint32_t pos,
1240                               void *data)
1241 {
1242         struct write_commit_graph_context *ctx = (struct write_commit_graph_context*)data;
1243         enum object_type type;
1244         off_t offset = nth_packed_object_offset(pack, pos);
1245         struct object_info oi = OBJECT_INFO_INIT;
1246
1247         if (ctx->progress)
1248                 display_progress(ctx->progress, ++ctx->progress_done);
1249
1250         oi.typep = &type;
1251         if (packed_object_info(ctx->r, pack, offset, &oi) < 0)
1252                 die(_("unable to get type of object %s"), oid_to_hex(oid));
1253
1254         if (type != OBJ_COMMIT)
1255                 return 0;
1256
1257         oid_array_append(&ctx->oids, oid);
1258         set_commit_pos(ctx->r, oid);
1259
1260         return 0;
1261 }
1262
1263 static void add_missing_parents(struct write_commit_graph_context *ctx, struct commit *commit)
1264 {
1265         struct commit_list *parent;
1266         for (parent = commit->parents; parent; parent = parent->next) {
1267                 if (!(parent->item->object.flags & REACHABLE)) {
1268                         oid_array_append(&ctx->oids, &parent->item->object.oid);
1269                         parent->item->object.flags |= REACHABLE;
1270                 }
1271         }
1272 }
1273
1274 static void close_reachable(struct write_commit_graph_context *ctx)
1275 {
1276         int i;
1277         struct commit *commit;
1278         enum commit_graph_split_flags flags = ctx->opts ?
1279                 ctx->opts->split_flags : COMMIT_GRAPH_SPLIT_UNSPECIFIED;
1280
1281         if (ctx->report_progress)
1282                 ctx->progress = start_delayed_progress(
1283                                         _("Loading known commits in commit graph"),
1284                                         ctx->oids.nr);
1285         for (i = 0; i < ctx->oids.nr; i++) {
1286                 display_progress(ctx->progress, i + 1);
1287                 commit = lookup_commit(ctx->r, &ctx->oids.oid[i]);
1288                 if (commit)
1289                         commit->object.flags |= REACHABLE;
1290         }
1291         stop_progress(&ctx->progress);
1292
1293         /*
1294          * As this loop runs, ctx->oids.nr may grow, but not more
1295          * than the number of missing commits in the reachable
1296          * closure.
1297          */
1298         if (ctx->report_progress)
1299                 ctx->progress = start_delayed_progress(
1300                                         _("Expanding reachable commits in commit graph"),
1301                                         0);
1302         for (i = 0; i < ctx->oids.nr; i++) {
1303                 display_progress(ctx->progress, i + 1);
1304                 commit = lookup_commit(ctx->r, &ctx->oids.oid[i]);
1305
1306                 if (!commit)
1307                         continue;
1308                 if (ctx->split) {
1309                         if ((!parse_commit(commit) &&
1310                              commit_graph_position(commit) == COMMIT_NOT_FROM_GRAPH) ||
1311                             flags == COMMIT_GRAPH_SPLIT_REPLACE)
1312                                 add_missing_parents(ctx, commit);
1313                 } else if (!parse_commit_no_graph(commit))
1314                         add_missing_parents(ctx, commit);
1315         }
1316         stop_progress(&ctx->progress);
1317
1318         if (ctx->report_progress)
1319                 ctx->progress = start_delayed_progress(
1320                                         _("Clearing commit marks in commit graph"),
1321                                         ctx->oids.nr);
1322         for (i = 0; i < ctx->oids.nr; i++) {
1323                 display_progress(ctx->progress, i + 1);
1324                 commit = lookup_commit(ctx->r, &ctx->oids.oid[i]);
1325
1326                 if (commit)
1327                         commit->object.flags &= ~REACHABLE;
1328         }
1329         stop_progress(&ctx->progress);
1330 }
1331
1332 static void compute_generation_numbers(struct write_commit_graph_context *ctx)
1333 {
1334         int i;
1335         struct commit_list *list = NULL;
1336
1337         if (ctx->report_progress)
1338                 ctx->progress = start_delayed_progress(
1339                                         _("Computing commit graph generation numbers"),
1340                                         ctx->commits.nr);
1341         for (i = 0; i < ctx->commits.nr; i++) {
1342                 uint32_t generation = commit_graph_data_at(ctx->commits.list[i])->generation;
1343
1344                 display_progress(ctx->progress, i + 1);
1345                 if (generation != GENERATION_NUMBER_INFINITY &&
1346                     generation != GENERATION_NUMBER_ZERO)
1347                         continue;
1348
1349                 commit_list_insert(ctx->commits.list[i], &list);
1350                 while (list) {
1351                         struct commit *current = list->item;
1352                         struct commit_list *parent;
1353                         int all_parents_computed = 1;
1354                         uint32_t max_generation = 0;
1355
1356                         for (parent = current->parents; parent; parent = parent->next) {
1357                                 generation = commit_graph_data_at(parent->item)->generation;
1358
1359                                 if (generation == GENERATION_NUMBER_INFINITY ||
1360                                     generation == GENERATION_NUMBER_ZERO) {
1361                                         all_parents_computed = 0;
1362                                         commit_list_insert(parent->item, &list);
1363                                         break;
1364                                 } else if (generation > max_generation) {
1365                                         max_generation = generation;
1366                                 }
1367                         }
1368
1369                         if (all_parents_computed) {
1370                                 struct commit_graph_data *data = commit_graph_data_at(current);
1371
1372                                 data->generation = max_generation + 1;
1373                                 pop_commit(&list);
1374
1375                                 if (data->generation > GENERATION_NUMBER_MAX)
1376                                         data->generation = GENERATION_NUMBER_MAX;
1377                         }
1378                 }
1379         }
1380         stop_progress(&ctx->progress);
1381 }
1382
1383 static void trace2_bloom_filter_write_statistics(struct write_commit_graph_context *ctx)
1384 {
1385         trace2_data_intmax("commit-graph", ctx->r, "filter-computed",
1386                            ctx->count_bloom_filter_computed);
1387         trace2_data_intmax("commit-graph", ctx->r, "filter-not-computed",
1388                            ctx->count_bloom_filter_not_computed);
1389         trace2_data_intmax("commit-graph", ctx->r, "filter-trunc-empty",
1390                            ctx->count_bloom_filter_trunc_empty);
1391         trace2_data_intmax("commit-graph", ctx->r, "filter-trunc-large",
1392                            ctx->count_bloom_filter_trunc_large);
1393 }
1394
1395 static void compute_bloom_filters(struct write_commit_graph_context *ctx)
1396 {
1397         int i;
1398         struct progress *progress = NULL;
1399         struct commit **sorted_commits;
1400         int max_new_filters;
1401
1402         init_bloom_filters();
1403
1404         if (ctx->report_progress)
1405                 progress = start_delayed_progress(
1406                         _("Computing commit changed paths Bloom filters"),
1407                         ctx->commits.nr);
1408
1409         ALLOC_ARRAY(sorted_commits, ctx->commits.nr);
1410         COPY_ARRAY(sorted_commits, ctx->commits.list, ctx->commits.nr);
1411
1412         if (ctx->order_by_pack)
1413                 QSORT(sorted_commits, ctx->commits.nr, commit_pos_cmp);
1414         else
1415                 QSORT(sorted_commits, ctx->commits.nr, commit_gen_cmp);
1416
1417         max_new_filters = ctx->opts && ctx->opts->max_new_filters >= 0 ?
1418                 ctx->opts->max_new_filters : ctx->commits.nr;
1419
1420         for (i = 0; i < ctx->commits.nr; i++) {
1421                 enum bloom_filter_computed computed = 0;
1422                 struct commit *c = sorted_commits[i];
1423                 struct bloom_filter *filter = get_or_compute_bloom_filter(
1424                         ctx->r,
1425                         c,
1426                         ctx->count_bloom_filter_computed < max_new_filters,
1427                         ctx->bloom_settings,
1428                         &computed);
1429                 if (computed & BLOOM_COMPUTED) {
1430                         ctx->count_bloom_filter_computed++;
1431                         if (computed & BLOOM_TRUNC_EMPTY)
1432                                 ctx->count_bloom_filter_trunc_empty++;
1433                         if (computed & BLOOM_TRUNC_LARGE)
1434                                 ctx->count_bloom_filter_trunc_large++;
1435                 } else if (computed & BLOOM_NOT_COMPUTED)
1436                         ctx->count_bloom_filter_not_computed++;
1437                 ctx->total_bloom_filter_data_size += filter
1438                         ? sizeof(unsigned char) * filter->len : 0;
1439                 display_progress(progress, i + 1);
1440         }
1441
1442         if (trace2_is_enabled())
1443                 trace2_bloom_filter_write_statistics(ctx);
1444
1445         free(sorted_commits);
1446         stop_progress(&progress);
1447 }
1448
1449 struct refs_cb_data {
1450         struct oidset *commits;
1451         struct progress *progress;
1452 };
1453
1454 static int add_ref_to_set(const char *refname,
1455                           const struct object_id *oid,
1456                           int flags, void *cb_data)
1457 {
1458         struct object_id peeled;
1459         struct refs_cb_data *data = (struct refs_cb_data *)cb_data;
1460
1461         if (!peel_ref(refname, &peeled))
1462                 oid = &peeled;
1463         if (oid_object_info(the_repository, oid, NULL) == OBJ_COMMIT)
1464                 oidset_insert(data->commits, oid);
1465
1466         display_progress(data->progress, oidset_size(data->commits));
1467
1468         return 0;
1469 }
1470
1471 int write_commit_graph_reachable(struct object_directory *odb,
1472                                  enum commit_graph_write_flags flags,
1473                                  const struct commit_graph_opts *opts)
1474 {
1475         struct oidset commits = OIDSET_INIT;
1476         struct refs_cb_data data;
1477         int result;
1478
1479         memset(&data, 0, sizeof(data));
1480         data.commits = &commits;
1481         if (flags & COMMIT_GRAPH_WRITE_PROGRESS)
1482                 data.progress = start_delayed_progress(
1483                         _("Collecting referenced commits"), 0);
1484
1485         for_each_ref(add_ref_to_set, &data);
1486
1487         stop_progress(&data.progress);
1488
1489         result = write_commit_graph(odb, NULL, &commits,
1490                                     flags, opts);
1491
1492         oidset_clear(&commits);
1493         return result;
1494 }
1495
1496 static int fill_oids_from_packs(struct write_commit_graph_context *ctx,
1497                                 struct string_list *pack_indexes)
1498 {
1499         uint32_t i;
1500         struct strbuf progress_title = STRBUF_INIT;
1501         struct strbuf packname = STRBUF_INIT;
1502         int dirlen;
1503
1504         strbuf_addf(&packname, "%s/pack/", ctx->odb->path);
1505         dirlen = packname.len;
1506         if (ctx->report_progress) {
1507                 strbuf_addf(&progress_title,
1508                             Q_("Finding commits for commit graph in %d pack",
1509                                "Finding commits for commit graph in %d packs",
1510                                pack_indexes->nr),
1511                             pack_indexes->nr);
1512                 ctx->progress = start_delayed_progress(progress_title.buf, 0);
1513                 ctx->progress_done = 0;
1514         }
1515         for (i = 0; i < pack_indexes->nr; i++) {
1516                 struct packed_git *p;
1517                 strbuf_setlen(&packname, dirlen);
1518                 strbuf_addstr(&packname, pack_indexes->items[i].string);
1519                 p = add_packed_git(packname.buf, packname.len, 1);
1520                 if (!p) {
1521                         error(_("error adding pack %s"), packname.buf);
1522                         return -1;
1523                 }
1524                 if (open_pack_index(p)) {
1525                         error(_("error opening index for %s"), packname.buf);
1526                         return -1;
1527                 }
1528                 for_each_object_in_pack(p, add_packed_commits, ctx,
1529                                         FOR_EACH_OBJECT_PACK_ORDER);
1530                 close_pack(p);
1531                 free(p);
1532         }
1533
1534         stop_progress(&ctx->progress);
1535         strbuf_release(&progress_title);
1536         strbuf_release(&packname);
1537
1538         return 0;
1539 }
1540
1541 static int fill_oids_from_commits(struct write_commit_graph_context *ctx,
1542                                   struct oidset *commits)
1543 {
1544         struct oidset_iter iter;
1545         struct object_id *oid;
1546
1547         if (!oidset_size(commits))
1548                 return 0;
1549
1550         oidset_iter_init(commits, &iter);
1551         while ((oid = oidset_iter_next(&iter))) {
1552                 oid_array_append(&ctx->oids, oid);
1553         }
1554
1555         return 0;
1556 }
1557
1558 static void fill_oids_from_all_packs(struct write_commit_graph_context *ctx)
1559 {
1560         if (ctx->report_progress)
1561                 ctx->progress = start_delayed_progress(
1562                         _("Finding commits for commit graph among packed objects"),
1563                         ctx->approx_nr_objects);
1564         for_each_packed_object(add_packed_commits, ctx,
1565                                FOR_EACH_OBJECT_PACK_ORDER);
1566         if (ctx->progress_done < ctx->approx_nr_objects)
1567                 display_progress(ctx->progress, ctx->approx_nr_objects);
1568         stop_progress(&ctx->progress);
1569 }
1570
1571 static void copy_oids_to_commits(struct write_commit_graph_context *ctx)
1572 {
1573         uint32_t i;
1574         enum commit_graph_split_flags flags = ctx->opts ?
1575                 ctx->opts->split_flags : COMMIT_GRAPH_SPLIT_UNSPECIFIED;
1576
1577         ctx->num_extra_edges = 0;
1578         if (ctx->report_progress)
1579                 ctx->progress = start_delayed_progress(
1580                         _("Finding extra edges in commit graph"),
1581                         ctx->oids.nr);
1582         oid_array_sort(&ctx->oids);
1583         for (i = 0; i < ctx->oids.nr; i = oid_array_next_unique(&ctx->oids, i)) {
1584                 unsigned int num_parents;
1585
1586                 display_progress(ctx->progress, i + 1);
1587
1588                 ALLOC_GROW(ctx->commits.list, ctx->commits.nr + 1, ctx->commits.alloc);
1589                 ctx->commits.list[ctx->commits.nr] = lookup_commit(ctx->r, &ctx->oids.oid[i]);
1590
1591                 if (ctx->split && flags != COMMIT_GRAPH_SPLIT_REPLACE &&
1592                     commit_graph_position(ctx->commits.list[ctx->commits.nr]) != COMMIT_NOT_FROM_GRAPH)
1593                         continue;
1594
1595                 if (ctx->split && flags == COMMIT_GRAPH_SPLIT_REPLACE)
1596                         parse_commit(ctx->commits.list[ctx->commits.nr]);
1597                 else
1598                         parse_commit_no_graph(ctx->commits.list[ctx->commits.nr]);
1599
1600                 num_parents = commit_list_count(ctx->commits.list[ctx->commits.nr]->parents);
1601                 if (num_parents > 2)
1602                         ctx->num_extra_edges += num_parents - 1;
1603
1604                 ctx->commits.nr++;
1605         }
1606         stop_progress(&ctx->progress);
1607 }
1608
1609 static int write_graph_chunk_base_1(struct hashfile *f,
1610                                     struct commit_graph *g)
1611 {
1612         int num = 0;
1613
1614         if (!g)
1615                 return 0;
1616
1617         num = write_graph_chunk_base_1(f, g->base_graph);
1618         hashwrite(f, g->oid.hash, the_hash_algo->rawsz);
1619         return num + 1;
1620 }
1621
1622 static int write_graph_chunk_base(struct hashfile *f,
1623                                   struct write_commit_graph_context *ctx)
1624 {
1625         int num = write_graph_chunk_base_1(f, ctx->new_base_graph);
1626
1627         if (num != ctx->num_commit_graphs_after - 1) {
1628                 error(_("failed to write correct number of base graph ids"));
1629                 return -1;
1630         }
1631
1632         return 0;
1633 }
1634
1635 typedef int (*chunk_write_fn)(struct hashfile *f,
1636                               struct write_commit_graph_context *ctx);
1637
1638 struct chunk_info {
1639         uint32_t id;
1640         uint64_t size;
1641         chunk_write_fn write_fn;
1642 };
1643
1644 static int write_commit_graph_file(struct write_commit_graph_context *ctx)
1645 {
1646         uint32_t i;
1647         int fd;
1648         struct hashfile *f;
1649         struct lock_file lk = LOCK_INIT;
1650         struct chunk_info chunks[MAX_NUM_CHUNKS + 1];
1651         const unsigned hashsz = the_hash_algo->rawsz;
1652         struct strbuf progress_title = STRBUF_INIT;
1653         int num_chunks = 3;
1654         uint64_t chunk_offset;
1655         struct object_id file_hash;
1656
1657         if (ctx->split) {
1658                 struct strbuf tmp_file = STRBUF_INIT;
1659
1660                 strbuf_addf(&tmp_file,
1661                             "%s/info/commit-graphs/tmp_graph_XXXXXX",
1662                             ctx->odb->path);
1663                 ctx->graph_name = strbuf_detach(&tmp_file, NULL);
1664         } else {
1665                 ctx->graph_name = get_commit_graph_filename(ctx->odb);
1666         }
1667
1668         if (safe_create_leading_directories(ctx->graph_name)) {
1669                 UNLEAK(ctx->graph_name);
1670                 error(_("unable to create leading directories of %s"),
1671                         ctx->graph_name);
1672                 return -1;
1673         }
1674
1675         if (ctx->split) {
1676                 char *lock_name = get_commit_graph_chain_filename(ctx->odb);
1677
1678                 hold_lock_file_for_update_mode(&lk, lock_name,
1679                                                LOCK_DIE_ON_ERROR, 0444);
1680
1681                 fd = git_mkstemp_mode(ctx->graph_name, 0444);
1682                 if (fd < 0) {
1683                         error(_("unable to create temporary graph layer"));
1684                         return -1;
1685                 }
1686
1687                 if (adjust_shared_perm(ctx->graph_name)) {
1688                         error(_("unable to adjust shared permissions for '%s'"),
1689                               ctx->graph_name);
1690                         return -1;
1691                 }
1692
1693                 f = hashfd(fd, ctx->graph_name);
1694         } else {
1695                 hold_lock_file_for_update_mode(&lk, ctx->graph_name,
1696                                                LOCK_DIE_ON_ERROR, 0444);
1697                 fd = get_lock_file_fd(&lk);
1698                 f = hashfd(fd, get_lock_file_path(&lk));
1699         }
1700
1701         chunks[0].id = GRAPH_CHUNKID_OIDFANOUT;
1702         chunks[0].size = GRAPH_FANOUT_SIZE;
1703         chunks[0].write_fn = write_graph_chunk_fanout;
1704         chunks[1].id = GRAPH_CHUNKID_OIDLOOKUP;
1705         chunks[1].size = hashsz * ctx->commits.nr;
1706         chunks[1].write_fn = write_graph_chunk_oids;
1707         chunks[2].id = GRAPH_CHUNKID_DATA;
1708         chunks[2].size = (hashsz + 16) * ctx->commits.nr;
1709         chunks[2].write_fn = write_graph_chunk_data;
1710         if (ctx->num_extra_edges) {
1711                 chunks[num_chunks].id = GRAPH_CHUNKID_EXTRAEDGES;
1712                 chunks[num_chunks].size = 4 * ctx->num_extra_edges;
1713                 chunks[num_chunks].write_fn = write_graph_chunk_extra_edges;
1714                 num_chunks++;
1715         }
1716         if (ctx->changed_paths) {
1717                 chunks[num_chunks].id = GRAPH_CHUNKID_BLOOMINDEXES;
1718                 chunks[num_chunks].size = sizeof(uint32_t) * ctx->commits.nr;
1719                 chunks[num_chunks].write_fn = write_graph_chunk_bloom_indexes;
1720                 num_chunks++;
1721                 chunks[num_chunks].id = GRAPH_CHUNKID_BLOOMDATA;
1722                 chunks[num_chunks].size = sizeof(uint32_t) * 3
1723                                           + ctx->total_bloom_filter_data_size;
1724                 chunks[num_chunks].write_fn = write_graph_chunk_bloom_data;
1725                 num_chunks++;
1726         }
1727         if (ctx->num_commit_graphs_after > 1) {
1728                 chunks[num_chunks].id = GRAPH_CHUNKID_BASE;
1729                 chunks[num_chunks].size = hashsz * (ctx->num_commit_graphs_after - 1);
1730                 chunks[num_chunks].write_fn = write_graph_chunk_base;
1731                 num_chunks++;
1732         }
1733
1734         chunks[num_chunks].id = 0;
1735         chunks[num_chunks].size = 0;
1736
1737         hashwrite_be32(f, GRAPH_SIGNATURE);
1738
1739         hashwrite_u8(f, GRAPH_VERSION);
1740         hashwrite_u8(f, oid_version());
1741         hashwrite_u8(f, num_chunks);
1742         hashwrite_u8(f, ctx->num_commit_graphs_after - 1);
1743
1744         chunk_offset = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
1745         for (i = 0; i <= num_chunks; i++) {
1746                 uint32_t chunk_write[3];
1747
1748                 chunk_write[0] = htonl(chunks[i].id);
1749                 chunk_write[1] = htonl(chunk_offset >> 32);
1750                 chunk_write[2] = htonl(chunk_offset & 0xffffffff);
1751                 hashwrite(f, chunk_write, 12);
1752
1753                 chunk_offset += chunks[i].size;
1754         }
1755
1756         if (ctx->report_progress) {
1757                 strbuf_addf(&progress_title,
1758                             Q_("Writing out commit graph in %d pass",
1759                                "Writing out commit graph in %d passes",
1760                                num_chunks),
1761                             num_chunks);
1762                 ctx->progress = start_delayed_progress(
1763                         progress_title.buf,
1764                         num_chunks * ctx->commits.nr);
1765         }
1766
1767         for (i = 0; i < num_chunks; i++) {
1768                 uint64_t start_offset = f->total + f->offset;
1769
1770                 if (chunks[i].write_fn(f, ctx))
1771                         return -1;
1772
1773                 if (f->total + f->offset != start_offset + chunks[i].size)
1774                         BUG("expected to write %"PRId64" bytes to chunk %"PRIx32", but wrote %"PRId64" instead",
1775                             chunks[i].size, chunks[i].id,
1776                             f->total + f->offset - start_offset);
1777         }
1778
1779         stop_progress(&ctx->progress);
1780         strbuf_release(&progress_title);
1781
1782         if (ctx->split && ctx->base_graph_name && ctx->num_commit_graphs_after > 1) {
1783                 char *new_base_hash = xstrdup(oid_to_hex(&ctx->new_base_graph->oid));
1784                 char *new_base_name = get_split_graph_filename(ctx->new_base_graph->odb, new_base_hash);
1785
1786                 free(ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2]);
1787                 free(ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2]);
1788                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2] = new_base_name;
1789                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2] = new_base_hash;
1790         }
1791
1792         close_commit_graph(ctx->r->objects);
1793         finalize_hashfile(f, file_hash.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
1794
1795         if (ctx->split) {
1796                 FILE *chainf = fdopen_lock_file(&lk, "w");
1797                 char *final_graph_name;
1798                 int result;
1799
1800                 close(fd);
1801
1802                 if (!chainf) {
1803                         error(_("unable to open commit-graph chain file"));
1804                         return -1;
1805                 }
1806
1807                 if (ctx->base_graph_name) {
1808                         const char *dest;
1809                         int idx = ctx->num_commit_graphs_after - 1;
1810                         if (ctx->num_commit_graphs_after > 1)
1811                                 idx--;
1812
1813                         dest = ctx->commit_graph_filenames_after[idx];
1814
1815                         if (strcmp(ctx->base_graph_name, dest)) {
1816                                 result = rename(ctx->base_graph_name, dest);
1817
1818                                 if (result) {
1819                                         error(_("failed to rename base commit-graph file"));
1820                                         return -1;
1821                                 }
1822                         }
1823                 } else {
1824                         char *graph_name = get_commit_graph_filename(ctx->odb);
1825                         unlink(graph_name);
1826                 }
1827
1828                 ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(oid_to_hex(&file_hash));
1829                 final_graph_name = get_split_graph_filename(ctx->odb,
1830                                         ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
1831                 ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1] = final_graph_name;
1832
1833                 result = rename(ctx->graph_name, final_graph_name);
1834
1835                 for (i = 0; i < ctx->num_commit_graphs_after; i++)
1836                         fprintf(get_lock_file_fp(&lk), "%s\n", ctx->commit_graph_hash_after[i]);
1837
1838                 if (result) {
1839                         error(_("failed to rename temporary commit-graph file"));
1840                         return -1;
1841                 }
1842         }
1843
1844         commit_lock_file(&lk);
1845
1846         return 0;
1847 }
1848
1849 static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
1850 {
1851         struct commit_graph *g;
1852         uint32_t num_commits;
1853         enum commit_graph_split_flags flags = COMMIT_GRAPH_SPLIT_UNSPECIFIED;
1854         uint32_t i;
1855
1856         int max_commits = 0;
1857         int size_mult = 2;
1858
1859         if (ctx->opts) {
1860                 max_commits = ctx->opts->max_commits;
1861
1862                 if (ctx->opts->size_multiple)
1863                         size_mult = ctx->opts->size_multiple;
1864
1865                 flags = ctx->opts->split_flags;
1866         }
1867
1868         g = ctx->r->objects->commit_graph;
1869         num_commits = ctx->commits.nr;
1870         if (flags == COMMIT_GRAPH_SPLIT_REPLACE)
1871                 ctx->num_commit_graphs_after = 1;
1872         else
1873                 ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1;
1874
1875         if (flags != COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED &&
1876             flags != COMMIT_GRAPH_SPLIT_REPLACE) {
1877                 while (g && (g->num_commits <= size_mult * num_commits ||
1878                             (max_commits && num_commits > max_commits))) {
1879                         if (g->odb != ctx->odb)
1880                                 break;
1881
1882                         num_commits += g->num_commits;
1883                         g = g->base_graph;
1884
1885                         ctx->num_commit_graphs_after--;
1886                 }
1887         }
1888
1889         if (flags != COMMIT_GRAPH_SPLIT_REPLACE)
1890                 ctx->new_base_graph = g;
1891         else if (ctx->num_commit_graphs_after != 1)
1892                 BUG("split_graph_merge_strategy: num_commit_graphs_after "
1893                     "should be 1 with --split=replace");
1894
1895         if (ctx->num_commit_graphs_after == 2) {
1896                 char *old_graph_name = get_commit_graph_filename(g->odb);
1897
1898                 if (!strcmp(g->filename, old_graph_name) &&
1899                     g->odb != ctx->odb) {
1900                         ctx->num_commit_graphs_after = 1;
1901                         ctx->new_base_graph = NULL;
1902                 }
1903
1904                 free(old_graph_name);
1905         }
1906
1907         CALLOC_ARRAY(ctx->commit_graph_filenames_after, ctx->num_commit_graphs_after);
1908         CALLOC_ARRAY(ctx->commit_graph_hash_after, ctx->num_commit_graphs_after);
1909
1910         for (i = 0; i < ctx->num_commit_graphs_after &&
1911                     i < ctx->num_commit_graphs_before; i++)
1912                 ctx->commit_graph_filenames_after[i] = xstrdup(ctx->commit_graph_filenames_before[i]);
1913
1914         i = ctx->num_commit_graphs_before - 1;
1915         g = ctx->r->objects->commit_graph;
1916
1917         while (g) {
1918                 if (i < ctx->num_commit_graphs_after)
1919                         ctx->commit_graph_hash_after[i] = xstrdup(oid_to_hex(&g->oid));
1920
1921                 i--;
1922                 g = g->base_graph;
1923         }
1924 }
1925
1926 static void merge_commit_graph(struct write_commit_graph_context *ctx,
1927                                struct commit_graph *g)
1928 {
1929         uint32_t i;
1930         uint32_t offset = g->num_commits_in_base;
1931
1932         ALLOC_GROW(ctx->commits.list, ctx->commits.nr + g->num_commits, ctx->commits.alloc);
1933
1934         for (i = 0; i < g->num_commits; i++) {
1935                 struct object_id oid;
1936                 struct commit *result;
1937
1938                 display_progress(ctx->progress, i + 1);
1939
1940                 load_oid_from_graph(g, i + offset, &oid);
1941
1942                 /* only add commits if they still exist in the repo */
1943                 result = lookup_commit_reference_gently(ctx->r, &oid, 1);
1944
1945                 if (result) {
1946                         ctx->commits.list[ctx->commits.nr] = result;
1947                         ctx->commits.nr++;
1948                 }
1949         }
1950 }
1951
1952 static int commit_compare(const void *_a, const void *_b)
1953 {
1954         const struct commit *a = *(const struct commit **)_a;
1955         const struct commit *b = *(const struct commit **)_b;
1956         return oidcmp(&a->object.oid, &b->object.oid);
1957 }
1958
1959 static void sort_and_scan_merged_commits(struct write_commit_graph_context *ctx)
1960 {
1961         uint32_t i, dedup_i = 0;
1962
1963         if (ctx->report_progress)
1964                 ctx->progress = start_delayed_progress(
1965                                         _("Scanning merged commits"),
1966                                         ctx->commits.nr);
1967
1968         QSORT(ctx->commits.list, ctx->commits.nr, commit_compare);
1969
1970         ctx->num_extra_edges = 0;
1971         for (i = 0; i < ctx->commits.nr; i++) {
1972                 display_progress(ctx->progress, i);
1973
1974                 if (i && oideq(&ctx->commits.list[i - 1]->object.oid,
1975                           &ctx->commits.list[i]->object.oid)) {
1976                         /*
1977                          * Silently ignore duplicates. These were likely
1978                          * created due to a commit appearing in multiple
1979                          * layers of the chain, which is unexpected but
1980                          * not invalid. We should make sure there is a
1981                          * unique copy in the new layer.
1982                          */
1983                 } else {
1984                         unsigned int num_parents;
1985
1986                         ctx->commits.list[dedup_i] = ctx->commits.list[i];
1987                         dedup_i++;
1988
1989                         num_parents = commit_list_count(ctx->commits.list[i]->parents);
1990                         if (num_parents > 2)
1991                                 ctx->num_extra_edges += num_parents - 1;
1992                 }
1993         }
1994
1995         ctx->commits.nr = dedup_i;
1996
1997         stop_progress(&ctx->progress);
1998 }
1999
2000 static void merge_commit_graphs(struct write_commit_graph_context *ctx)
2001 {
2002         struct commit_graph *g = ctx->r->objects->commit_graph;
2003         uint32_t current_graph_number = ctx->num_commit_graphs_before;
2004
2005         while (g && current_graph_number >= ctx->num_commit_graphs_after) {
2006                 current_graph_number--;
2007
2008                 if (ctx->report_progress)
2009                         ctx->progress = start_delayed_progress(_("Merging commit-graph"), 0);
2010
2011                 merge_commit_graph(ctx, g);
2012                 stop_progress(&ctx->progress);
2013
2014                 g = g->base_graph;
2015         }
2016
2017         if (g) {
2018                 ctx->new_base_graph = g;
2019                 ctx->new_num_commits_in_base = g->num_commits + g->num_commits_in_base;
2020         }
2021
2022         if (ctx->new_base_graph)
2023                 ctx->base_graph_name = xstrdup(ctx->new_base_graph->filename);
2024
2025         sort_and_scan_merged_commits(ctx);
2026 }
2027
2028 static void mark_commit_graphs(struct write_commit_graph_context *ctx)
2029 {
2030         uint32_t i;
2031         time_t now = time(NULL);
2032
2033         for (i = ctx->num_commit_graphs_after - 1; i < ctx->num_commit_graphs_before; i++) {
2034                 struct stat st;
2035                 struct utimbuf updated_time;
2036
2037                 stat(ctx->commit_graph_filenames_before[i], &st);
2038
2039                 updated_time.actime = st.st_atime;
2040                 updated_time.modtime = now;
2041                 utime(ctx->commit_graph_filenames_before[i], &updated_time);
2042         }
2043 }
2044
2045 static void expire_commit_graphs(struct write_commit_graph_context *ctx)
2046 {
2047         struct strbuf path = STRBUF_INIT;
2048         DIR *dir;
2049         struct dirent *de;
2050         size_t dirnamelen;
2051         timestamp_t expire_time = time(NULL);
2052
2053         if (ctx->opts && ctx->opts->expire_time)
2054                 expire_time = ctx->opts->expire_time;
2055         if (!ctx->split) {
2056                 char *chain_file_name = get_commit_graph_chain_filename(ctx->odb);
2057                 unlink(chain_file_name);
2058                 free(chain_file_name);
2059                 ctx->num_commit_graphs_after = 0;
2060         }
2061
2062         strbuf_addstr(&path, ctx->odb->path);
2063         strbuf_addstr(&path, "/info/commit-graphs");
2064         dir = opendir(path.buf);
2065
2066         if (!dir)
2067                 goto out;
2068
2069         strbuf_addch(&path, '/');
2070         dirnamelen = path.len;
2071         while ((de = readdir(dir)) != NULL) {
2072                 struct stat st;
2073                 uint32_t i, found = 0;
2074
2075                 strbuf_setlen(&path, dirnamelen);
2076                 strbuf_addstr(&path, de->d_name);
2077
2078                 stat(path.buf, &st);
2079
2080                 if (st.st_mtime > expire_time)
2081                         continue;
2082                 if (path.len < 6 || strcmp(path.buf + path.len - 6, ".graph"))
2083                         continue;
2084
2085                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
2086                         if (!strcmp(ctx->commit_graph_filenames_after[i],
2087                                     path.buf)) {
2088                                 found = 1;
2089                                 break;
2090                         }
2091                 }
2092
2093                 if (!found)
2094                         unlink(path.buf);
2095         }
2096
2097 out:
2098         strbuf_release(&path);
2099 }
2100
2101 int write_commit_graph(struct object_directory *odb,
2102                        struct string_list *pack_indexes,
2103                        struct oidset *commits,
2104                        enum commit_graph_write_flags flags,
2105                        const struct commit_graph_opts *opts)
2106 {
2107         struct write_commit_graph_context *ctx;
2108         uint32_t i;
2109         int res = 0;
2110         int replace = 0;
2111         struct bloom_filter_settings bloom_settings = DEFAULT_BLOOM_FILTER_SETTINGS;
2112
2113         prepare_repo_settings(the_repository);
2114         if (!the_repository->settings.core_commit_graph) {
2115                 warning(_("attempting to write a commit-graph, but 'core.commitGraph' is disabled"));
2116                 return 0;
2117         }
2118         if (!commit_graph_compatible(the_repository))
2119                 return 0;
2120
2121         ctx = xcalloc(1, sizeof(struct write_commit_graph_context));
2122         ctx->r = the_repository;
2123         ctx->odb = odb;
2124         ctx->append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0;
2125         ctx->report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0;
2126         ctx->split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0;
2127         ctx->opts = opts;
2128         ctx->total_bloom_filter_data_size = 0;
2129
2130         bloom_settings.bits_per_entry = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_BITS_PER_ENTRY",
2131                                                       bloom_settings.bits_per_entry);
2132         bloom_settings.num_hashes = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_NUM_HASHES",
2133                                                   bloom_settings.num_hashes);
2134         bloom_settings.max_changed_paths = git_env_ulong("GIT_TEST_BLOOM_SETTINGS_MAX_CHANGED_PATHS",
2135                                                          bloom_settings.max_changed_paths);
2136         ctx->bloom_settings = &bloom_settings;
2137
2138         if (flags & COMMIT_GRAPH_WRITE_BLOOM_FILTERS)
2139                 ctx->changed_paths = 1;
2140         if (!(flags & COMMIT_GRAPH_NO_WRITE_BLOOM_FILTERS)) {
2141                 struct commit_graph *g;
2142                 prepare_commit_graph_one(ctx->r, ctx->odb);
2143
2144                 g = ctx->r->objects->commit_graph;
2145
2146                 /* We have changed-paths already. Keep them in the next graph */
2147                 if (g && g->chunk_bloom_data) {
2148                         ctx->changed_paths = 1;
2149                         ctx->bloom_settings = g->bloom_filter_settings;
2150                 }
2151         }
2152
2153         if (ctx->split) {
2154                 struct commit_graph *g;
2155                 prepare_commit_graph(ctx->r);
2156
2157                 g = ctx->r->objects->commit_graph;
2158
2159                 while (g) {
2160                         ctx->num_commit_graphs_before++;
2161                         g = g->base_graph;
2162                 }
2163
2164                 if (ctx->num_commit_graphs_before) {
2165                         ALLOC_ARRAY(ctx->commit_graph_filenames_before, ctx->num_commit_graphs_before);
2166                         i = ctx->num_commit_graphs_before;
2167                         g = ctx->r->objects->commit_graph;
2168
2169                         while (g) {
2170                                 ctx->commit_graph_filenames_before[--i] = xstrdup(g->filename);
2171                                 g = g->base_graph;
2172                         }
2173                 }
2174
2175                 if (ctx->opts)
2176                         replace = ctx->opts->split_flags & COMMIT_GRAPH_SPLIT_REPLACE;
2177         }
2178
2179         ctx->approx_nr_objects = approximate_object_count();
2180
2181         if (ctx->append)
2182                 prepare_commit_graph_one(ctx->r, ctx->odb);
2183
2184         if (ctx->append && ctx->r->objects->commit_graph) {
2185                 struct commit_graph *g = ctx->r->objects->commit_graph;
2186                 for (i = 0; i < g->num_commits; i++) {
2187                         struct object_id oid;
2188                         hashcpy(oid.hash, g->chunk_oid_lookup + g->hash_len * i);
2189                         oid_array_append(&ctx->oids, &oid);
2190                 }
2191         }
2192
2193         if (pack_indexes) {
2194                 ctx->order_by_pack = 1;
2195                 if ((res = fill_oids_from_packs(ctx, pack_indexes)))
2196                         goto cleanup;
2197         }
2198
2199         if (commits) {
2200                 if ((res = fill_oids_from_commits(ctx, commits)))
2201                         goto cleanup;
2202         }
2203
2204         if (!pack_indexes && !commits) {
2205                 ctx->order_by_pack = 1;
2206                 fill_oids_from_all_packs(ctx);
2207         }
2208
2209         close_reachable(ctx);
2210
2211         copy_oids_to_commits(ctx);
2212
2213         if (ctx->commits.nr >= GRAPH_EDGE_LAST_MASK) {
2214                 error(_("too many commits to write graph"));
2215                 res = -1;
2216                 goto cleanup;
2217         }
2218
2219         if (!ctx->commits.nr && !replace)
2220                 goto cleanup;
2221
2222         if (ctx->split) {
2223                 split_graph_merge_strategy(ctx);
2224
2225                 if (!replace)
2226                         merge_commit_graphs(ctx);
2227         } else
2228                 ctx->num_commit_graphs_after = 1;
2229
2230         compute_generation_numbers(ctx);
2231
2232         if (ctx->changed_paths)
2233                 compute_bloom_filters(ctx);
2234
2235         res = write_commit_graph_file(ctx);
2236
2237         if (ctx->split)
2238                 mark_commit_graphs(ctx);
2239
2240         expire_commit_graphs(ctx);
2241
2242 cleanup:
2243         free(ctx->graph_name);
2244         free(ctx->commits.list);
2245         oid_array_clear(&ctx->oids);
2246
2247         if (ctx->commit_graph_filenames_after) {
2248                 for (i = 0; i < ctx->num_commit_graphs_after; i++) {
2249                         free(ctx->commit_graph_filenames_after[i]);
2250                         free(ctx->commit_graph_hash_after[i]);
2251                 }
2252
2253                 for (i = 0; i < ctx->num_commit_graphs_before; i++)
2254                         free(ctx->commit_graph_filenames_before[i]);
2255
2256                 free(ctx->commit_graph_filenames_after);
2257                 free(ctx->commit_graph_filenames_before);
2258                 free(ctx->commit_graph_hash_after);
2259         }
2260
2261         free(ctx);
2262
2263         return res;
2264 }
2265
2266 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
2267 static int verify_commit_graph_error;
2268
2269 static void graph_report(const char *fmt, ...)
2270 {
2271         va_list ap;
2272
2273         verify_commit_graph_error = 1;
2274         va_start(ap, fmt);
2275         vfprintf(stderr, fmt, ap);
2276         fprintf(stderr, "\n");
2277         va_end(ap);
2278 }
2279
2280 #define GENERATION_ZERO_EXISTS 1
2281 #define GENERATION_NUMBER_EXISTS 2
2282
2283 int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
2284 {
2285         uint32_t i, cur_fanout_pos = 0;
2286         struct object_id prev_oid, cur_oid, checksum;
2287         int generation_zero = 0;
2288         struct hashfile *f;
2289         int devnull;
2290         struct progress *progress = NULL;
2291         int local_error = 0;
2292
2293         if (!g) {
2294                 graph_report("no commit-graph file loaded");
2295                 return 1;
2296         }
2297
2298         verify_commit_graph_error = verify_commit_graph_lite(g);
2299         if (verify_commit_graph_error)
2300                 return verify_commit_graph_error;
2301
2302         devnull = open("/dev/null", O_WRONLY);
2303         f = hashfd(devnull, NULL);
2304         hashwrite(f, g->data, g->data_len - g->hash_len);
2305         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
2306         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
2307                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
2308                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
2309         }
2310
2311         for (i = 0; i < g->num_commits; i++) {
2312                 struct commit *graph_commit;
2313
2314                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
2315
2316                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
2317                         graph_report(_("commit-graph has incorrect OID order: %s then %s"),
2318                                      oid_to_hex(&prev_oid),
2319                                      oid_to_hex(&cur_oid));
2320
2321                 oidcpy(&prev_oid, &cur_oid);
2322
2323                 while (cur_oid.hash[0] > cur_fanout_pos) {
2324                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
2325
2326                         if (i != fanout_value)
2327                                 graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
2328                                              cur_fanout_pos, fanout_value, i);
2329                         cur_fanout_pos++;
2330                 }
2331
2332                 graph_commit = lookup_commit(r, &cur_oid);
2333                 if (!parse_commit_in_graph_one(r, g, graph_commit))
2334                         graph_report(_("failed to parse commit %s from commit-graph"),
2335                                      oid_to_hex(&cur_oid));
2336         }
2337
2338         while (cur_fanout_pos < 256) {
2339                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
2340
2341                 if (g->num_commits != fanout_value)
2342                         graph_report(_("commit-graph has incorrect fanout value: fanout[%d] = %u != %u"),
2343                                      cur_fanout_pos, fanout_value, i);
2344
2345                 cur_fanout_pos++;
2346         }
2347
2348         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
2349                 return verify_commit_graph_error;
2350
2351         if (flags & COMMIT_GRAPH_WRITE_PROGRESS)
2352                 progress = start_progress(_("Verifying commits in commit graph"),
2353                                         g->num_commits);
2354
2355         for (i = 0; i < g->num_commits; i++) {
2356                 struct commit *graph_commit, *odb_commit;
2357                 struct commit_list *graph_parents, *odb_parents;
2358                 uint32_t max_generation = 0;
2359                 uint32_t generation;
2360
2361                 display_progress(progress, i + 1);
2362                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
2363
2364                 graph_commit = lookup_commit(r, &cur_oid);
2365                 odb_commit = (struct commit *)create_object(r, &cur_oid, alloc_commit_node(r));
2366                 if (parse_commit_internal(odb_commit, 0, 0)) {
2367                         graph_report(_("failed to parse commit %s from object database for commit-graph"),
2368                                      oid_to_hex(&cur_oid));
2369                         continue;
2370                 }
2371
2372                 if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
2373                            get_commit_tree_oid(odb_commit)))
2374                         graph_report(_("root tree OID for commit %s in commit-graph is %s != %s"),
2375                                      oid_to_hex(&cur_oid),
2376                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
2377                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
2378
2379                 graph_parents = graph_commit->parents;
2380                 odb_parents = odb_commit->parents;
2381
2382                 while (graph_parents) {
2383                         if (odb_parents == NULL) {
2384                                 graph_report(_("commit-graph parent list for commit %s is too long"),
2385                                              oid_to_hex(&cur_oid));
2386                                 break;
2387                         }
2388
2389                         /* parse parent in case it is in a base graph */
2390                         parse_commit_in_graph_one(r, g, graph_parents->item);
2391
2392                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
2393                                 graph_report(_("commit-graph parent for %s is %s != %s"),
2394                                              oid_to_hex(&cur_oid),
2395                                              oid_to_hex(&graph_parents->item->object.oid),
2396                                              oid_to_hex(&odb_parents->item->object.oid));
2397
2398                         generation = commit_graph_generation(graph_parents->item);
2399                         if (generation > max_generation)
2400                                 max_generation = generation;
2401
2402                         graph_parents = graph_parents->next;
2403                         odb_parents = odb_parents->next;
2404                 }
2405
2406                 if (odb_parents != NULL)
2407                         graph_report(_("commit-graph parent list for commit %s terminates early"),
2408                                      oid_to_hex(&cur_oid));
2409
2410                 if (!commit_graph_generation(graph_commit)) {
2411                         if (generation_zero == GENERATION_NUMBER_EXISTS)
2412                                 graph_report(_("commit-graph has generation number zero for commit %s, but non-zero elsewhere"),
2413                                              oid_to_hex(&cur_oid));
2414                         generation_zero = GENERATION_ZERO_EXISTS;
2415                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
2416                         graph_report(_("commit-graph has non-zero generation number for commit %s, but zero elsewhere"),
2417                                      oid_to_hex(&cur_oid));
2418
2419                 if (generation_zero == GENERATION_ZERO_EXISTS)
2420                         continue;
2421
2422                 /*
2423                  * If one of our parents has generation GENERATION_NUMBER_MAX, then
2424                  * our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
2425                  * extra logic in the following condition.
2426                  */
2427                 if (max_generation == GENERATION_NUMBER_MAX)
2428                         max_generation--;
2429
2430                 generation = commit_graph_generation(graph_commit);
2431                 if (generation != max_generation + 1)
2432                         graph_report(_("commit-graph generation for commit %s is %u != %u"),
2433                                      oid_to_hex(&cur_oid),
2434                                      generation,
2435                                      max_generation + 1);
2436
2437                 if (graph_commit->date != odb_commit->date)
2438                         graph_report(_("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime),
2439                                      oid_to_hex(&cur_oid),
2440                                      graph_commit->date,
2441                                      odb_commit->date);
2442         }
2443         stop_progress(&progress);
2444
2445         local_error = verify_commit_graph_error;
2446
2447         if (!(flags & COMMIT_GRAPH_VERIFY_SHALLOW) && g->base_graph)
2448                 local_error |= verify_commit_graph(r, g->base_graph, flags);
2449
2450         return local_error;
2451 }
2452
2453 void free_commit_graph(struct commit_graph *g)
2454 {
2455         if (!g)
2456                 return;
2457         if (g->data) {
2458                 munmap((void *)g->data, g->data_len);
2459                 g->data = NULL;
2460         }
2461         free(g->filename);
2462         free(g->bloom_filter_settings);
2463         free(g);
2464 }
2465
2466 void disable_commit_graph(struct repository *r)
2467 {
2468         r->commit_graph_disabled = 1;
2469 }