Merge branch 'ea/rebase-compat-doc-fix'
[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
26 #define GRAPH_DATA_WIDTH (the_hash_algo->rawsz + 16)
27
28 #define GRAPH_VERSION_1 0x1
29 #define GRAPH_VERSION GRAPH_VERSION_1
30
31 #define GRAPH_EXTRA_EDGES_NEEDED 0x80000000
32 #define GRAPH_EDGE_LAST_MASK 0x7fffffff
33 #define GRAPH_PARENT_NONE 0x70000000
34
35 #define GRAPH_LAST_EDGE 0x80000000
36
37 #define GRAPH_HEADER_SIZE 8
38 #define GRAPH_FANOUT_SIZE (4 * 256)
39 #define GRAPH_CHUNKLOOKUP_WIDTH 12
40 #define GRAPH_MIN_SIZE (GRAPH_HEADER_SIZE + 4 * GRAPH_CHUNKLOOKUP_WIDTH \
41                         + GRAPH_FANOUT_SIZE + the_hash_algo->rawsz)
42
43 char *get_commit_graph_filename(const char *obj_dir)
44 {
45         return xstrfmt("%s/info/commit-graph", obj_dir);
46 }
47
48 static uint8_t oid_version(void)
49 {
50         return 1;
51 }
52
53 static struct commit_graph *alloc_commit_graph(void)
54 {
55         struct commit_graph *g = xcalloc(1, sizeof(*g));
56         g->graph_fd = -1;
57
58         return g;
59 }
60
61 extern int read_replace_refs;
62
63 static int commit_graph_compatible(struct repository *r)
64 {
65         if (!r->gitdir)
66                 return 0;
67
68         if (read_replace_refs) {
69                 prepare_replace_object(r);
70                 if (hashmap_get_size(&r->objects->replace_map->map))
71                         return 0;
72         }
73
74         prepare_commit_graft(r);
75         if (r->parsed_objects && r->parsed_objects->grafts_nr)
76                 return 0;
77         if (is_repository_shallow(r))
78                 return 0;
79
80         return 1;
81 }
82
83 struct commit_graph *load_commit_graph_one(const char *graph_file)
84 {
85         void *graph_map;
86         size_t graph_size;
87         struct stat st;
88         struct commit_graph *ret;
89         int fd = git_open(graph_file);
90
91         if (fd < 0)
92                 return NULL;
93         if (fstat(fd, &st)) {
94                 close(fd);
95                 return NULL;
96         }
97         graph_size = xsize_t(st.st_size);
98
99         if (graph_size < GRAPH_MIN_SIZE) {
100                 close(fd);
101                 die(_("graph file %s is too small"), graph_file);
102         }
103         graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
104         ret = parse_commit_graph(graph_map, fd, graph_size);
105
106         if (!ret) {
107                 munmap(graph_map, graph_size);
108                 close(fd);
109                 exit(1);
110         }
111
112         return ret;
113 }
114
115 struct commit_graph *parse_commit_graph(void *graph_map, int fd,
116                                         size_t graph_size)
117 {
118         const unsigned char *data, *chunk_lookup;
119         uint32_t i;
120         struct commit_graph *graph;
121         uint64_t last_chunk_offset;
122         uint32_t last_chunk_id;
123         uint32_t graph_signature;
124         unsigned char graph_version, hash_version;
125
126         if (!graph_map)
127                 return NULL;
128
129         if (graph_size < GRAPH_MIN_SIZE)
130                 return NULL;
131
132         data = (const unsigned char *)graph_map;
133
134         graph_signature = get_be32(data);
135         if (graph_signature != GRAPH_SIGNATURE) {
136                 error(_("graph signature %X does not match signature %X"),
137                       graph_signature, GRAPH_SIGNATURE);
138                 return NULL;
139         }
140
141         graph_version = *(unsigned char*)(data + 4);
142         if (graph_version != GRAPH_VERSION) {
143                 error(_("graph version %X does not match version %X"),
144                       graph_version, GRAPH_VERSION);
145                 return NULL;
146         }
147
148         hash_version = *(unsigned char*)(data + 5);
149         if (hash_version != oid_version()) {
150                 error(_("hash version %X does not match version %X"),
151                       hash_version, oid_version());
152                 return NULL;
153         }
154
155         graph = alloc_commit_graph();
156
157         graph->hash_len = the_hash_algo->rawsz;
158         graph->num_chunks = *(unsigned char*)(data + 6);
159         graph->graph_fd = fd;
160         graph->data = graph_map;
161         graph->data_len = graph_size;
162
163         last_chunk_id = 0;
164         last_chunk_offset = 8;
165         chunk_lookup = data + 8;
166         for (i = 0; i < graph->num_chunks; i++) {
167                 uint32_t chunk_id;
168                 uint64_t chunk_offset;
169                 int chunk_repeated = 0;
170
171                 if (data + graph_size - chunk_lookup <
172                     GRAPH_CHUNKLOOKUP_WIDTH) {
173                         error(_("chunk lookup table entry missing; graph file may be incomplete"));
174                         free(graph);
175                         return NULL;
176                 }
177
178                 chunk_id = get_be32(chunk_lookup + 0);
179                 chunk_offset = get_be64(chunk_lookup + 4);
180
181                 chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
182
183                 if (chunk_offset > graph_size - the_hash_algo->rawsz) {
184                         error(_("improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
185                               (uint32_t)chunk_offset);
186                         free(graph);
187                         return NULL;
188                 }
189
190                 switch (chunk_id) {
191                 case GRAPH_CHUNKID_OIDFANOUT:
192                         if (graph->chunk_oid_fanout)
193                                 chunk_repeated = 1;
194                         else
195                                 graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
196                         break;
197
198                 case GRAPH_CHUNKID_OIDLOOKUP:
199                         if (graph->chunk_oid_lookup)
200                                 chunk_repeated = 1;
201                         else
202                                 graph->chunk_oid_lookup = data + chunk_offset;
203                         break;
204
205                 case GRAPH_CHUNKID_DATA:
206                         if (graph->chunk_commit_data)
207                                 chunk_repeated = 1;
208                         else
209                                 graph->chunk_commit_data = data + chunk_offset;
210                         break;
211
212                 case GRAPH_CHUNKID_EXTRAEDGES:
213                         if (graph->chunk_extra_edges)
214                                 chunk_repeated = 1;
215                         else
216                                 graph->chunk_extra_edges = data + chunk_offset;
217                         break;
218                 }
219
220                 if (chunk_repeated) {
221                         error(_("chunk id %08x appears multiple times"), chunk_id);
222                         free(graph);
223                         return NULL;
224                 }
225
226                 if (last_chunk_id == GRAPH_CHUNKID_OIDLOOKUP)
227                 {
228                         graph->num_commits = (chunk_offset - last_chunk_offset)
229                                              / graph->hash_len;
230                 }
231
232                 last_chunk_id = chunk_id;
233                 last_chunk_offset = chunk_offset;
234         }
235
236         return graph;
237 }
238
239 static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
240 {
241         char *graph_name;
242
243         if (r->objects->commit_graph)
244                 return;
245
246         graph_name = get_commit_graph_filename(obj_dir);
247         r->objects->commit_graph =
248                 load_commit_graph_one(graph_name);
249
250         FREE_AND_NULL(graph_name);
251 }
252
253 /*
254  * Return 1 if commit_graph is non-NULL, and 0 otherwise.
255  *
256  * On the first invocation, this function attemps to load the commit
257  * graph if the_repository is configured to have one.
258  */
259 static int prepare_commit_graph(struct repository *r)
260 {
261         struct object_directory *odb;
262         int config_value;
263
264         if (r->objects->commit_graph_attempted)
265                 return !!r->objects->commit_graph;
266         r->objects->commit_graph_attempted = 1;
267
268         if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) &&
269             (repo_config_get_bool(r, "core.commitgraph", &config_value) ||
270             !config_value))
271                 /*
272                  * This repository is not configured to use commit graphs, so
273                  * do not load one. (But report commit_graph_attempted anyway
274                  * so that commit graph loading is not attempted again for this
275                  * repository.)
276                  */
277                 return 0;
278
279         if (!commit_graph_compatible(r))
280                 return 0;
281
282         prepare_alt_odb(r);
283         for (odb = r->objects->odb;
284              !r->objects->commit_graph && odb;
285              odb = odb->next)
286                 prepare_commit_graph_one(r, odb->path);
287         return !!r->objects->commit_graph;
288 }
289
290 int generation_numbers_enabled(struct repository *r)
291 {
292         uint32_t first_generation;
293         struct commit_graph *g;
294         if (!prepare_commit_graph(r))
295                return 0;
296
297         g = r->objects->commit_graph;
298
299         if (!g->num_commits)
300                 return 0;
301
302         first_generation = get_be32(g->chunk_commit_data +
303                                     g->hash_len + 8) >> 2;
304
305         return !!first_generation;
306 }
307
308 void close_commit_graph(struct repository *r)
309 {
310         free_commit_graph(r->objects->commit_graph);
311         r->objects->commit_graph = NULL;
312 }
313
314 static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
315 {
316         return bsearch_hash(oid->hash, g->chunk_oid_fanout,
317                             g->chunk_oid_lookup, g->hash_len, pos);
318 }
319
320 static struct commit_list **insert_parent_or_die(struct repository *r,
321                                                  struct commit_graph *g,
322                                                  uint64_t pos,
323                                                  struct commit_list **pptr)
324 {
325         struct commit *c;
326         struct object_id oid;
327
328         if (pos >= g->num_commits)
329                 die("invalid parent position %"PRIu64, pos);
330
331         hashcpy(oid.hash, g->chunk_oid_lookup + g->hash_len * pos);
332         c = lookup_commit(r, &oid);
333         if (!c)
334                 die(_("could not find commit %s"), oid_to_hex(&oid));
335         c->graph_pos = pos;
336         return &commit_list_insert(c, pptr)->next;
337 }
338
339 static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
340 {
341         const unsigned char *commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * pos;
342         item->graph_pos = pos;
343         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
344 }
345
346 static int fill_commit_in_graph(struct repository *r,
347                                 struct commit *item,
348                                 struct commit_graph *g, uint32_t pos)
349 {
350         uint32_t edge_value;
351         uint32_t *parent_data_ptr;
352         uint64_t date_low, date_high;
353         struct commit_list **pptr;
354         const unsigned char *commit_data = g->chunk_commit_data + (g->hash_len + 16) * pos;
355
356         item->object.parsed = 1;
357         item->graph_pos = pos;
358
359         item->maybe_tree = NULL;
360
361         date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
362         date_low = get_be32(commit_data + g->hash_len + 12);
363         item->date = (timestamp_t)((date_high << 32) | date_low);
364
365         item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
366
367         pptr = &item->parents;
368
369         edge_value = get_be32(commit_data + g->hash_len);
370         if (edge_value == GRAPH_PARENT_NONE)
371                 return 1;
372         pptr = insert_parent_or_die(r, g, edge_value, pptr);
373
374         edge_value = get_be32(commit_data + g->hash_len + 4);
375         if (edge_value == GRAPH_PARENT_NONE)
376                 return 1;
377         if (!(edge_value & GRAPH_EXTRA_EDGES_NEEDED)) {
378                 pptr = insert_parent_or_die(r, g, edge_value, pptr);
379                 return 1;
380         }
381
382         parent_data_ptr = (uint32_t*)(g->chunk_extra_edges +
383                           4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
384         do {
385                 edge_value = get_be32(parent_data_ptr);
386                 pptr = insert_parent_or_die(r, g,
387                                             edge_value & GRAPH_EDGE_LAST_MASK,
388                                             pptr);
389                 parent_data_ptr++;
390         } while (!(edge_value & GRAPH_LAST_EDGE));
391
392         return 1;
393 }
394
395 static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
396 {
397         if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
398                 *pos = item->graph_pos;
399                 return 1;
400         } else {
401                 return bsearch_graph(g, &(item->object.oid), pos);
402         }
403 }
404
405 static int parse_commit_in_graph_one(struct repository *r,
406                                      struct commit_graph *g,
407                                      struct commit *item)
408 {
409         uint32_t pos;
410
411         if (item->object.parsed)
412                 return 1;
413
414         if (find_commit_in_graph(item, g, &pos))
415                 return fill_commit_in_graph(r, item, g, pos);
416
417         return 0;
418 }
419
420 int parse_commit_in_graph(struct repository *r, struct commit *item)
421 {
422         if (!prepare_commit_graph(r))
423                 return 0;
424         return parse_commit_in_graph_one(r, r->objects->commit_graph, item);
425 }
426
427 void load_commit_graph_info(struct repository *r, struct commit *item)
428 {
429         uint32_t pos;
430         if (!prepare_commit_graph(r))
431                 return;
432         if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
433                 fill_commit_graph_info(item, r->objects->commit_graph, pos);
434 }
435
436 static struct tree *load_tree_for_commit(struct repository *r,
437                                          struct commit_graph *g,
438                                          struct commit *c)
439 {
440         struct object_id oid;
441         const unsigned char *commit_data = g->chunk_commit_data +
442                                            GRAPH_DATA_WIDTH * (c->graph_pos);
443
444         hashcpy(oid.hash, commit_data);
445         c->maybe_tree = lookup_tree(r, &oid);
446
447         return c->maybe_tree;
448 }
449
450 static struct tree *get_commit_tree_in_graph_one(struct repository *r,
451                                                  struct commit_graph *g,
452                                                  const struct commit *c)
453 {
454         if (c->maybe_tree)
455                 return c->maybe_tree;
456         if (c->graph_pos == COMMIT_NOT_FROM_GRAPH)
457                 BUG("get_commit_tree_in_graph_one called from non-commit-graph commit");
458
459         return load_tree_for_commit(r, g, (struct commit *)c);
460 }
461
462 struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
463 {
464         return get_commit_tree_in_graph_one(r, r->objects->commit_graph, c);
465 }
466
467 static void write_graph_chunk_fanout(struct hashfile *f,
468                                      struct commit **commits,
469                                      int nr_commits,
470                                      struct progress *progress,
471                                      uint64_t *progress_cnt)
472 {
473         int i, count = 0;
474         struct commit **list = commits;
475
476         /*
477          * Write the first-level table (the list is sorted,
478          * but we use a 256-entry lookup to be able to avoid
479          * having to do eight extra binary search iterations).
480          */
481         for (i = 0; i < 256; i++) {
482                 while (count < nr_commits) {
483                         if ((*list)->object.oid.hash[0] != i)
484                                 break;
485                         display_progress(progress, ++*progress_cnt);
486                         count++;
487                         list++;
488                 }
489
490                 hashwrite_be32(f, count);
491         }
492 }
493
494 static void write_graph_chunk_oids(struct hashfile *f, int hash_len,
495                                    struct commit **commits, int nr_commits,
496                                    struct progress *progress,
497                                    uint64_t *progress_cnt)
498 {
499         struct commit **list = commits;
500         int count;
501         for (count = 0; count < nr_commits; count++, list++) {
502                 display_progress(progress, ++*progress_cnt);
503                 hashwrite(f, (*list)->object.oid.hash, (int)hash_len);
504         }
505 }
506
507 static const unsigned char *commit_to_sha1(size_t index, void *table)
508 {
509         struct commit **commits = table;
510         return commits[index]->object.oid.hash;
511 }
512
513 static void write_graph_chunk_data(struct hashfile *f, int hash_len,
514                                    struct commit **commits, int nr_commits,
515                                    struct progress *progress,
516                                    uint64_t *progress_cnt)
517 {
518         struct commit **list = commits;
519         struct commit **last = commits + nr_commits;
520         uint32_t num_extra_edges = 0;
521
522         while (list < last) {
523                 struct commit_list *parent;
524                 int edge_value;
525                 uint32_t packedDate[2];
526                 display_progress(progress, ++*progress_cnt);
527
528                 parse_commit(*list);
529                 hashwrite(f, get_commit_tree_oid(*list)->hash, hash_len);
530
531                 parent = (*list)->parents;
532
533                 if (!parent)
534                         edge_value = GRAPH_PARENT_NONE;
535                 else {
536                         edge_value = sha1_pos(parent->item->object.oid.hash,
537                                               commits,
538                                               nr_commits,
539                                               commit_to_sha1);
540
541                         if (edge_value < 0)
542                                 BUG("missing parent %s for commit %s",
543                                     oid_to_hex(&parent->item->object.oid),
544                                     oid_to_hex(&(*list)->object.oid));
545                 }
546
547                 hashwrite_be32(f, edge_value);
548
549                 if (parent)
550                         parent = parent->next;
551
552                 if (!parent)
553                         edge_value = GRAPH_PARENT_NONE;
554                 else if (parent->next)
555                         edge_value = GRAPH_EXTRA_EDGES_NEEDED | num_extra_edges;
556                 else {
557                         edge_value = sha1_pos(parent->item->object.oid.hash,
558                                               commits,
559                                               nr_commits,
560                                               commit_to_sha1);
561                         if (edge_value < 0)
562                                 BUG("missing parent %s for commit %s",
563                                     oid_to_hex(&parent->item->object.oid),
564                                     oid_to_hex(&(*list)->object.oid));
565                 }
566
567                 hashwrite_be32(f, edge_value);
568
569                 if (edge_value & GRAPH_EXTRA_EDGES_NEEDED) {
570                         do {
571                                 num_extra_edges++;
572                                 parent = parent->next;
573                         } while (parent);
574                 }
575
576                 if (sizeof((*list)->date) > 4)
577                         packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
578                 else
579                         packedDate[0] = 0;
580
581                 packedDate[0] |= htonl((*list)->generation << 2);
582
583                 packedDate[1] = htonl((*list)->date);
584                 hashwrite(f, packedDate, 8);
585
586                 list++;
587         }
588 }
589
590 static void write_graph_chunk_extra_edges(struct hashfile *f,
591                                           struct commit **commits,
592                                           int nr_commits,
593                                           struct progress *progress,
594                                           uint64_t *progress_cnt)
595 {
596         struct commit **list = commits;
597         struct commit **last = commits + nr_commits;
598         struct commit_list *parent;
599
600         while (list < last) {
601                 int num_parents = 0;
602
603                 display_progress(progress, ++*progress_cnt);
604
605                 for (parent = (*list)->parents; num_parents < 3 && parent;
606                      parent = parent->next)
607                         num_parents++;
608
609                 if (num_parents <= 2) {
610                         list++;
611                         continue;
612                 }
613
614                 /* Since num_parents > 2, this initializer is safe. */
615                 for (parent = (*list)->parents->next; parent; parent = parent->next) {
616                         int edge_value = sha1_pos(parent->item->object.oid.hash,
617                                                   commits,
618                                                   nr_commits,
619                                                   commit_to_sha1);
620
621                         if (edge_value < 0)
622                                 BUG("missing parent %s for commit %s",
623                                     oid_to_hex(&parent->item->object.oid),
624                                     oid_to_hex(&(*list)->object.oid));
625                         else if (!parent->next)
626                                 edge_value |= GRAPH_LAST_EDGE;
627
628                         hashwrite_be32(f, edge_value);
629                 }
630
631                 list++;
632         }
633 }
634
635 static int commit_compare(const void *_a, const void *_b)
636 {
637         const struct object_id *a = (const struct object_id *)_a;
638         const struct object_id *b = (const struct object_id *)_b;
639         return oidcmp(a, b);
640 }
641
642 struct packed_commit_list {
643         struct commit **list;
644         int nr;
645         int alloc;
646 };
647
648 struct packed_oid_list {
649         struct object_id *list;
650         int nr;
651         int alloc;
652         struct progress *progress;
653         int progress_done;
654 };
655
656 static int add_packed_commits(const struct object_id *oid,
657                               struct packed_git *pack,
658                               uint32_t pos,
659                               void *data)
660 {
661         struct packed_oid_list *list = (struct packed_oid_list*)data;
662         enum object_type type;
663         off_t offset = nth_packed_object_offset(pack, pos);
664         struct object_info oi = OBJECT_INFO_INIT;
665
666         if (list->progress)
667                 display_progress(list->progress, ++list->progress_done);
668
669         oi.typep = &type;
670         if (packed_object_info(the_repository, pack, offset, &oi) < 0)
671                 die(_("unable to get type of object %s"), oid_to_hex(oid));
672
673         if (type != OBJ_COMMIT)
674                 return 0;
675
676         ALLOC_GROW(list->list, list->nr + 1, list->alloc);
677         oidcpy(&(list->list[list->nr]), oid);
678         list->nr++;
679
680         return 0;
681 }
682
683 static void add_missing_parents(struct packed_oid_list *oids, struct commit *commit)
684 {
685         struct commit_list *parent;
686         for (parent = commit->parents; parent; parent = parent->next) {
687                 if (!(parent->item->object.flags & UNINTERESTING)) {
688                         ALLOC_GROW(oids->list, oids->nr + 1, oids->alloc);
689                         oidcpy(&oids->list[oids->nr], &(parent->item->object.oid));
690                         oids->nr++;
691                         parent->item->object.flags |= UNINTERESTING;
692                 }
693         }
694 }
695
696 static void close_reachable(struct packed_oid_list *oids, int report_progress)
697 {
698         int i;
699         struct commit *commit;
700         struct progress *progress = NULL;
701
702         if (report_progress)
703                 progress = start_delayed_progress(
704                         _("Loading known commits in commit graph"), oids->nr);
705         for (i = 0; i < oids->nr; i++) {
706                 display_progress(progress, i + 1);
707                 commit = lookup_commit(the_repository, &oids->list[i]);
708                 if (commit)
709                         commit->object.flags |= UNINTERESTING;
710         }
711         stop_progress(&progress);
712
713         /*
714          * As this loop runs, oids->nr may grow, but not more
715          * than the number of missing commits in the reachable
716          * closure.
717          */
718         if (report_progress)
719                 progress = start_delayed_progress(
720                         _("Expanding reachable commits in commit graph"), oids->nr);
721         for (i = 0; i < oids->nr; i++) {
722                 display_progress(progress, i + 1);
723                 commit = lookup_commit(the_repository, &oids->list[i]);
724
725                 if (commit && !parse_commit(commit))
726                         add_missing_parents(oids, commit);
727         }
728         stop_progress(&progress);
729
730         if (report_progress)
731                 progress = start_delayed_progress(
732                         _("Clearing commit marks in commit graph"), oids->nr);
733         for (i = 0; i < oids->nr; i++) {
734                 display_progress(progress, i + 1);
735                 commit = lookup_commit(the_repository, &oids->list[i]);
736
737                 if (commit)
738                         commit->object.flags &= ~UNINTERESTING;
739         }
740         stop_progress(&progress);
741 }
742
743 static void compute_generation_numbers(struct packed_commit_list* commits,
744                                        int report_progress)
745 {
746         int i;
747         struct commit_list *list = NULL;
748         struct progress *progress = NULL;
749
750         if (report_progress)
751                 progress = start_progress(
752                         _("Computing commit graph generation numbers"),
753                         commits->nr);
754         for (i = 0; i < commits->nr; i++) {
755                 display_progress(progress, i + 1);
756                 if (commits->list[i]->generation != GENERATION_NUMBER_INFINITY &&
757                     commits->list[i]->generation != GENERATION_NUMBER_ZERO)
758                         continue;
759
760                 commit_list_insert(commits->list[i], &list);
761                 while (list) {
762                         struct commit *current = list->item;
763                         struct commit_list *parent;
764                         int all_parents_computed = 1;
765                         uint32_t max_generation = 0;
766
767                         for (parent = current->parents; parent; parent = parent->next) {
768                                 if (parent->item->generation == GENERATION_NUMBER_INFINITY ||
769                                     parent->item->generation == GENERATION_NUMBER_ZERO) {
770                                         all_parents_computed = 0;
771                                         commit_list_insert(parent->item, &list);
772                                         break;
773                                 } else if (parent->item->generation > max_generation) {
774                                         max_generation = parent->item->generation;
775                                 }
776                         }
777
778                         if (all_parents_computed) {
779                                 current->generation = max_generation + 1;
780                                 pop_commit(&list);
781
782                                 if (current->generation > GENERATION_NUMBER_MAX)
783                                         current->generation = GENERATION_NUMBER_MAX;
784                         }
785                 }
786         }
787         stop_progress(&progress);
788 }
789
790 static int add_ref_to_list(const char *refname,
791                            const struct object_id *oid,
792                            int flags, void *cb_data)
793 {
794         struct string_list *list = (struct string_list *)cb_data;
795
796         string_list_append(list, oid_to_hex(oid));
797         return 0;
798 }
799
800 void write_commit_graph_reachable(const char *obj_dir, int append,
801                                   int report_progress)
802 {
803         struct string_list list = STRING_LIST_INIT_DUP;
804
805         for_each_ref(add_ref_to_list, &list);
806         write_commit_graph(obj_dir, NULL, &list, append, report_progress);
807
808         string_list_clear(&list, 0);
809 }
810
811 void write_commit_graph(const char *obj_dir,
812                         struct string_list *pack_indexes,
813                         struct string_list *commit_hex,
814                         int append, int report_progress)
815 {
816         struct packed_oid_list oids;
817         struct packed_commit_list commits;
818         struct hashfile *f;
819         uint32_t i, count_distinct = 0;
820         char *graph_name;
821         struct lock_file lk = LOCK_INIT;
822         uint32_t chunk_ids[5];
823         uint64_t chunk_offsets[5];
824         int num_chunks;
825         int num_extra_edges;
826         struct commit_list *parent;
827         struct progress *progress = NULL;
828         const unsigned hashsz = the_hash_algo->rawsz;
829         uint64_t progress_cnt = 0;
830         struct strbuf progress_title = STRBUF_INIT;
831         unsigned long approx_nr_objects;
832
833         if (!commit_graph_compatible(the_repository))
834                 return;
835
836         oids.nr = 0;
837         approx_nr_objects = approximate_object_count();
838         oids.alloc = approx_nr_objects / 32;
839         oids.progress = NULL;
840         oids.progress_done = 0;
841
842         if (append) {
843                 prepare_commit_graph_one(the_repository, obj_dir);
844                 if (the_repository->objects->commit_graph)
845                         oids.alloc += the_repository->objects->commit_graph->num_commits;
846         }
847
848         if (oids.alloc < 1024)
849                 oids.alloc = 1024;
850         ALLOC_ARRAY(oids.list, oids.alloc);
851
852         if (append && the_repository->objects->commit_graph) {
853                 struct commit_graph *commit_graph =
854                         the_repository->objects->commit_graph;
855                 for (i = 0; i < commit_graph->num_commits; i++) {
856                         const unsigned char *hash = commit_graph->chunk_oid_lookup +
857                                 commit_graph->hash_len * i;
858                         hashcpy(oids.list[oids.nr++].hash, hash);
859                 }
860         }
861
862         if (pack_indexes) {
863                 struct strbuf packname = STRBUF_INIT;
864                 int dirlen;
865                 strbuf_addf(&packname, "%s/pack/", obj_dir);
866                 dirlen = packname.len;
867                 if (report_progress) {
868                         strbuf_addf(&progress_title,
869                                     Q_("Finding commits for commit graph in %d pack",
870                                        "Finding commits for commit graph in %d packs",
871                                        pack_indexes->nr),
872                                     pack_indexes->nr);
873                         oids.progress = start_delayed_progress(progress_title.buf, 0);
874                         oids.progress_done = 0;
875                 }
876                 for (i = 0; i < pack_indexes->nr; i++) {
877                         struct packed_git *p;
878                         strbuf_setlen(&packname, dirlen);
879                         strbuf_addstr(&packname, pack_indexes->items[i].string);
880                         p = add_packed_git(packname.buf, packname.len, 1);
881                         if (!p)
882                                 die(_("error adding pack %s"), packname.buf);
883                         if (open_pack_index(p))
884                                 die(_("error opening index for %s"), packname.buf);
885                         for_each_object_in_pack(p, add_packed_commits, &oids,
886                                                 FOR_EACH_OBJECT_PACK_ORDER);
887                         close_pack(p);
888                         free(p);
889                 }
890                 stop_progress(&oids.progress);
891                 strbuf_reset(&progress_title);
892                 strbuf_release(&packname);
893         }
894
895         if (commit_hex) {
896                 if (report_progress) {
897                         strbuf_addf(&progress_title,
898                                     Q_("Finding commits for commit graph from %d ref",
899                                        "Finding commits for commit graph from %d refs",
900                                        commit_hex->nr),
901                                     commit_hex->nr);
902                         progress = start_delayed_progress(progress_title.buf,
903                                                           commit_hex->nr);
904                 }
905                 for (i = 0; i < commit_hex->nr; i++) {
906                         const char *end;
907                         struct object_id oid;
908                         struct commit *result;
909
910                         display_progress(progress, i + 1);
911                         if (commit_hex->items[i].string &&
912                             parse_oid_hex(commit_hex->items[i].string, &oid, &end))
913                                 continue;
914
915                         result = lookup_commit_reference_gently(the_repository, &oid, 1);
916
917                         if (result) {
918                                 ALLOC_GROW(oids.list, oids.nr + 1, oids.alloc);
919                                 oidcpy(&oids.list[oids.nr], &(result->object.oid));
920                                 oids.nr++;
921                         }
922                 }
923                 stop_progress(&progress);
924                 strbuf_reset(&progress_title);
925         }
926
927         if (!pack_indexes && !commit_hex) {
928                 if (report_progress)
929                         oids.progress = start_delayed_progress(
930                                 _("Finding commits for commit graph among packed objects"),
931                                 approx_nr_objects);
932                 for_each_packed_object(add_packed_commits, &oids,
933                                        FOR_EACH_OBJECT_PACK_ORDER);
934                 if (oids.progress_done < approx_nr_objects)
935                         display_progress(oids.progress, approx_nr_objects);
936                 stop_progress(&oids.progress);
937         }
938
939         close_reachable(&oids, report_progress);
940
941         if (report_progress)
942                 progress = start_delayed_progress(
943                         _("Counting distinct commits in commit graph"),
944                         oids.nr);
945         display_progress(progress, 0); /* TODO: Measure QSORT() progress */
946         QSORT(oids.list, oids.nr, commit_compare);
947         count_distinct = 1;
948         for (i = 1; i < oids.nr; i++) {
949                 display_progress(progress, i + 1);
950                 if (!oideq(&oids.list[i - 1], &oids.list[i]))
951                         count_distinct++;
952         }
953         stop_progress(&progress);
954
955         if (count_distinct >= GRAPH_EDGE_LAST_MASK)
956                 die(_("the commit graph format cannot write %d commits"), count_distinct);
957
958         commits.nr = 0;
959         commits.alloc = count_distinct;
960         ALLOC_ARRAY(commits.list, commits.alloc);
961
962         num_extra_edges = 0;
963         if (report_progress)
964                 progress = start_delayed_progress(
965                         _("Finding extra edges in commit graph"),
966                         oids.nr);
967         for (i = 0; i < oids.nr; i++) {
968                 int num_parents = 0;
969                 display_progress(progress, i + 1);
970                 if (i > 0 && oideq(&oids.list[i - 1], &oids.list[i]))
971                         continue;
972
973                 commits.list[commits.nr] = lookup_commit(the_repository, &oids.list[i]);
974                 parse_commit(commits.list[commits.nr]);
975
976                 for (parent = commits.list[commits.nr]->parents;
977                      parent; parent = parent->next)
978                         num_parents++;
979
980                 if (num_parents > 2)
981                         num_extra_edges += num_parents - 1;
982
983                 commits.nr++;
984         }
985         num_chunks = num_extra_edges ? 4 : 3;
986         stop_progress(&progress);
987
988         if (commits.nr >= GRAPH_EDGE_LAST_MASK)
989                 die(_("too many commits to write graph"));
990
991         compute_generation_numbers(&commits, report_progress);
992
993         graph_name = get_commit_graph_filename(obj_dir);
994         if (safe_create_leading_directories(graph_name)) {
995                 UNLEAK(graph_name);
996                 die_errno(_("unable to create leading directories of %s"),
997                           graph_name);
998         }
999
1000         hold_lock_file_for_update(&lk, graph_name, LOCK_DIE_ON_ERROR);
1001         f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
1002
1003         hashwrite_be32(f, GRAPH_SIGNATURE);
1004
1005         hashwrite_u8(f, GRAPH_VERSION);
1006         hashwrite_u8(f, oid_version());
1007         hashwrite_u8(f, num_chunks);
1008         hashwrite_u8(f, 0); /* unused padding byte */
1009
1010         chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
1011         chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
1012         chunk_ids[2] = GRAPH_CHUNKID_DATA;
1013         if (num_extra_edges)
1014                 chunk_ids[3] = GRAPH_CHUNKID_EXTRAEDGES;
1015         else
1016                 chunk_ids[3] = 0;
1017         chunk_ids[4] = 0;
1018
1019         chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
1020         chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
1021         chunk_offsets[2] = chunk_offsets[1] + hashsz * commits.nr;
1022         chunk_offsets[3] = chunk_offsets[2] + (hashsz + 16) * commits.nr;
1023         chunk_offsets[4] = chunk_offsets[3] + 4 * num_extra_edges;
1024
1025         for (i = 0; i <= num_chunks; i++) {
1026                 uint32_t chunk_write[3];
1027
1028                 chunk_write[0] = htonl(chunk_ids[i]);
1029                 chunk_write[1] = htonl(chunk_offsets[i] >> 32);
1030                 chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
1031                 hashwrite(f, chunk_write, 12);
1032         }
1033
1034         if (report_progress) {
1035                 strbuf_addf(&progress_title,
1036                             Q_("Writing out commit graph in %d pass",
1037                                "Writing out commit graph in %d passes",
1038                                num_chunks),
1039                             num_chunks);
1040                 progress = start_delayed_progress(
1041                         progress_title.buf,
1042                         num_chunks * commits.nr);
1043         }
1044         write_graph_chunk_fanout(f, commits.list, commits.nr, progress, &progress_cnt);
1045         write_graph_chunk_oids(f, hashsz, commits.list, commits.nr, progress, &progress_cnt);
1046         write_graph_chunk_data(f, hashsz, commits.list, commits.nr, progress, &progress_cnt);
1047         if (num_extra_edges)
1048                 write_graph_chunk_extra_edges(f, commits.list, commits.nr, progress, &progress_cnt);
1049         stop_progress(&progress);
1050         strbuf_release(&progress_title);
1051
1052         close_commit_graph(the_repository);
1053         finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
1054         commit_lock_file(&lk);
1055
1056         free(graph_name);
1057         free(commits.list);
1058         free(oids.list);
1059 }
1060
1061 #define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
1062 static int verify_commit_graph_error;
1063
1064 static void graph_report(const char *fmt, ...)
1065 {
1066         va_list ap;
1067
1068         verify_commit_graph_error = 1;
1069         va_start(ap, fmt);
1070         vfprintf(stderr, fmt, ap);
1071         fprintf(stderr, "\n");
1072         va_end(ap);
1073 }
1074
1075 #define GENERATION_ZERO_EXISTS 1
1076 #define GENERATION_NUMBER_EXISTS 2
1077
1078 int verify_commit_graph(struct repository *r, struct commit_graph *g)
1079 {
1080         uint32_t i, cur_fanout_pos = 0;
1081         struct object_id prev_oid, cur_oid, checksum;
1082         int generation_zero = 0;
1083         struct hashfile *f;
1084         int devnull;
1085         struct progress *progress = NULL;
1086
1087         if (!g) {
1088                 graph_report("no commit-graph file loaded");
1089                 return 1;
1090         }
1091
1092         verify_commit_graph_error = 0;
1093
1094         if (!g->chunk_oid_fanout)
1095                 graph_report("commit-graph is missing the OID Fanout chunk");
1096         if (!g->chunk_oid_lookup)
1097                 graph_report("commit-graph is missing the OID Lookup chunk");
1098         if (!g->chunk_commit_data)
1099                 graph_report("commit-graph is missing the Commit Data chunk");
1100
1101         if (verify_commit_graph_error)
1102                 return verify_commit_graph_error;
1103
1104         devnull = open("/dev/null", O_WRONLY);
1105         f = hashfd(devnull, NULL);
1106         hashwrite(f, g->data, g->data_len - g->hash_len);
1107         finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
1108         if (!hasheq(checksum.hash, g->data + g->data_len - g->hash_len)) {
1109                 graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
1110                 verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
1111         }
1112
1113         for (i = 0; i < g->num_commits; i++) {
1114                 struct commit *graph_commit;
1115
1116                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1117
1118                 if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
1119                         graph_report("commit-graph has incorrect OID order: %s then %s",
1120                                      oid_to_hex(&prev_oid),
1121                                      oid_to_hex(&cur_oid));
1122
1123                 oidcpy(&prev_oid, &cur_oid);
1124
1125                 while (cur_oid.hash[0] > cur_fanout_pos) {
1126                         uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1127
1128                         if (i != fanout_value)
1129                                 graph_report("commit-graph has incorrect fanout value: fanout[%d] = %u != %u",
1130                                              cur_fanout_pos, fanout_value, i);
1131                         cur_fanout_pos++;
1132                 }
1133
1134                 graph_commit = lookup_commit(r, &cur_oid);
1135                 if (!parse_commit_in_graph_one(r, g, graph_commit))
1136                         graph_report("failed to parse %s from commit-graph",
1137                                      oid_to_hex(&cur_oid));
1138         }
1139
1140         while (cur_fanout_pos < 256) {
1141                 uint32_t fanout_value = get_be32(g->chunk_oid_fanout + cur_fanout_pos);
1142
1143                 if (g->num_commits != fanout_value)
1144                         graph_report("commit-graph has incorrect fanout value: fanout[%d] = %u != %u",
1145                                      cur_fanout_pos, fanout_value, i);
1146
1147                 cur_fanout_pos++;
1148         }
1149
1150         if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
1151                 return verify_commit_graph_error;
1152
1153         progress = start_progress(_("Verifying commits in commit graph"),
1154                                   g->num_commits);
1155         for (i = 0; i < g->num_commits; i++) {
1156                 struct commit *graph_commit, *odb_commit;
1157                 struct commit_list *graph_parents, *odb_parents;
1158                 uint32_t max_generation = 0;
1159
1160                 display_progress(progress, i + 1);
1161                 hashcpy(cur_oid.hash, g->chunk_oid_lookup + g->hash_len * i);
1162
1163                 graph_commit = lookup_commit(r, &cur_oid);
1164                 odb_commit = (struct commit *)create_object(r, cur_oid.hash, alloc_commit_node(r));
1165                 if (parse_commit_internal(odb_commit, 0, 0)) {
1166                         graph_report("failed to parse %s from object database",
1167                                      oid_to_hex(&cur_oid));
1168                         continue;
1169                 }
1170
1171                 if (!oideq(&get_commit_tree_in_graph_one(r, g, graph_commit)->object.oid,
1172                            get_commit_tree_oid(odb_commit)))
1173                         graph_report("root tree OID for commit %s in commit-graph is %s != %s",
1174                                      oid_to_hex(&cur_oid),
1175                                      oid_to_hex(get_commit_tree_oid(graph_commit)),
1176                                      oid_to_hex(get_commit_tree_oid(odb_commit)));
1177
1178                 graph_parents = graph_commit->parents;
1179                 odb_parents = odb_commit->parents;
1180
1181                 while (graph_parents) {
1182                         if (odb_parents == NULL) {
1183                                 graph_report("commit-graph parent list for commit %s is too long",
1184                                              oid_to_hex(&cur_oid));
1185                                 break;
1186                         }
1187
1188                         if (!oideq(&graph_parents->item->object.oid, &odb_parents->item->object.oid))
1189                                 graph_report("commit-graph parent for %s is %s != %s",
1190                                              oid_to_hex(&cur_oid),
1191                                              oid_to_hex(&graph_parents->item->object.oid),
1192                                              oid_to_hex(&odb_parents->item->object.oid));
1193
1194                         if (graph_parents->item->generation > max_generation)
1195                                 max_generation = graph_parents->item->generation;
1196
1197                         graph_parents = graph_parents->next;
1198                         odb_parents = odb_parents->next;
1199                 }
1200
1201                 if (odb_parents != NULL)
1202                         graph_report("commit-graph parent list for commit %s terminates early",
1203                                      oid_to_hex(&cur_oid));
1204
1205                 if (!graph_commit->generation) {
1206                         if (generation_zero == GENERATION_NUMBER_EXISTS)
1207                                 graph_report("commit-graph has generation number zero for commit %s, but non-zero elsewhere",
1208                                              oid_to_hex(&cur_oid));
1209                         generation_zero = GENERATION_ZERO_EXISTS;
1210                 } else if (generation_zero == GENERATION_ZERO_EXISTS)
1211                         graph_report("commit-graph has non-zero generation number for commit %s, but zero elsewhere",
1212                                      oid_to_hex(&cur_oid));
1213
1214                 if (generation_zero == GENERATION_ZERO_EXISTS)
1215                         continue;
1216
1217                 /*
1218                  * If one of our parents has generation GENERATION_NUMBER_MAX, then
1219                  * our generation is also GENERATION_NUMBER_MAX. Decrement to avoid
1220                  * extra logic in the following condition.
1221                  */
1222                 if (max_generation == GENERATION_NUMBER_MAX)
1223                         max_generation--;
1224
1225                 if (graph_commit->generation != max_generation + 1)
1226                         graph_report("commit-graph generation for commit %s is %u != %u",
1227                                      oid_to_hex(&cur_oid),
1228                                      graph_commit->generation,
1229                                      max_generation + 1);
1230
1231                 if (graph_commit->date != odb_commit->date)
1232                         graph_report("commit date for commit %s in commit-graph is %"PRItime" != %"PRItime,
1233                                      oid_to_hex(&cur_oid),
1234                                      graph_commit->date,
1235                                      odb_commit->date);
1236         }
1237         stop_progress(&progress);
1238
1239         return verify_commit_graph_error;
1240 }
1241
1242 void free_commit_graph(struct commit_graph *g)
1243 {
1244         if (!g)
1245                 return;
1246         if (g->graph_fd >= 0) {
1247                 munmap((void *)g->data, g->data_len);
1248                 g->data = NULL;
1249                 close(g->graph_fd);
1250         }
1251         free(g);
1252 }