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