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