Merge branch 'sg/test-bash-version-fix'
[git] / pack-bitmap.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "tag.h"
4 #include "diff.h"
5 #include "revision.h"
6 #include "progress.h"
7 #include "list-objects.h"
8 #include "pack.h"
9 #include "pack-bitmap.h"
10 #include "pack-revindex.h"
11 #include "pack-objects.h"
12 #include "packfile.h"
13 #include "repository.h"
14 #include "object-store.h"
15
16 /*
17  * An entry on the bitmap index, representing the bitmap for a given
18  * commit.
19  */
20 struct stored_bitmap {
21         unsigned char sha1[20];
22         struct ewah_bitmap *root;
23         struct stored_bitmap *xor;
24         int flags;
25 };
26
27 /*
28  * The active bitmap index for a repository. By design, repositories only have
29  * a single bitmap index available (the index for the biggest packfile in
30  * the repository), since bitmap indexes need full closure.
31  *
32  * If there is more than one bitmap index available (e.g. because of alternates),
33  * the active bitmap index is the largest one.
34  */
35 struct bitmap_index {
36         /* Packfile to which this bitmap index belongs to */
37         struct packed_git *pack;
38
39         /*
40          * Mark the first `reuse_objects` in the packfile as reused:
41          * they will be sent as-is without using them for repacking
42          * calculations
43          */
44         uint32_t reuse_objects;
45
46         /* mmapped buffer of the whole bitmap index */
47         unsigned char *map;
48         size_t map_size; /* size of the mmaped buffer */
49         size_t map_pos; /* current position when loading the index */
50
51         /*
52          * Type indexes.
53          *
54          * Each bitmap marks which objects in the packfile  are of the given
55          * type. This provides type information when yielding the objects from
56          * the packfile during a walk, which allows for better delta bases.
57          */
58         struct ewah_bitmap *commits;
59         struct ewah_bitmap *trees;
60         struct ewah_bitmap *blobs;
61         struct ewah_bitmap *tags;
62
63         /* Map from SHA1 -> `stored_bitmap` for all the bitmapped commits */
64         khash_sha1 *bitmaps;
65
66         /* Number of bitmapped commits */
67         uint32_t entry_count;
68
69         /* If not NULL, this is a name-hash cache pointing into map. */
70         uint32_t *hashes;
71
72         /*
73          * Extended index.
74          *
75          * When trying to perform bitmap operations with objects that are not
76          * packed in `pack`, these objects are added to this "fake index" and
77          * are assumed to appear at the end of the packfile for all operations
78          */
79         struct eindex {
80                 struct object **objects;
81                 uint32_t *hashes;
82                 uint32_t count, alloc;
83                 khash_sha1_pos *positions;
84         } ext_index;
85
86         /* Bitmap result of the last performed walk */
87         struct bitmap *result;
88
89         /* "have" bitmap from the last performed walk */
90         struct bitmap *haves;
91
92         /* Version of the bitmap index */
93         unsigned int version;
94 };
95
96 static struct ewah_bitmap *lookup_stored_bitmap(struct stored_bitmap *st)
97 {
98         struct ewah_bitmap *parent;
99         struct ewah_bitmap *composed;
100
101         if (st->xor == NULL)
102                 return st->root;
103
104         composed = ewah_pool_new();
105         parent = lookup_stored_bitmap(st->xor);
106         ewah_xor(st->root, parent, composed);
107
108         ewah_pool_free(st->root);
109         st->root = composed;
110         st->xor = NULL;
111
112         return composed;
113 }
114
115 /*
116  * Read a bitmap from the current read position on the mmaped
117  * index, and increase the read position accordingly
118  */
119 static struct ewah_bitmap *read_bitmap_1(struct bitmap_index *index)
120 {
121         struct ewah_bitmap *b = ewah_pool_new();
122
123         ssize_t bitmap_size = ewah_read_mmap(b,
124                 index->map + index->map_pos,
125                 index->map_size - index->map_pos);
126
127         if (bitmap_size < 0) {
128                 error("Failed to load bitmap index (corrupted?)");
129                 ewah_pool_free(b);
130                 return NULL;
131         }
132
133         index->map_pos += bitmap_size;
134         return b;
135 }
136
137 static int load_bitmap_header(struct bitmap_index *index)
138 {
139         struct bitmap_disk_header *header = (void *)index->map;
140
141         if (index->map_size < sizeof(*header) + 20)
142                 return error("Corrupted bitmap index (missing header data)");
143
144         if (memcmp(header->magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE)) != 0)
145                 return error("Corrupted bitmap index file (wrong header)");
146
147         index->version = ntohs(header->version);
148         if (index->version != 1)
149                 return error("Unsupported version for bitmap index file (%d)", index->version);
150
151         /* Parse known bitmap format options */
152         {
153                 uint32_t flags = ntohs(header->options);
154
155                 if ((flags & BITMAP_OPT_FULL_DAG) == 0)
156                         return error("Unsupported options for bitmap index file "
157                                 "(Git requires BITMAP_OPT_FULL_DAG)");
158
159                 if (flags & BITMAP_OPT_HASH_CACHE) {
160                         unsigned char *end = index->map + index->map_size - 20;
161                         index->hashes = ((uint32_t *)end) - index->pack->num_objects;
162                 }
163         }
164
165         index->entry_count = ntohl(header->entry_count);
166         index->map_pos += sizeof(*header);
167         return 0;
168 }
169
170 static struct stored_bitmap *store_bitmap(struct bitmap_index *index,
171                                           struct ewah_bitmap *root,
172                                           const unsigned char *sha1,
173                                           struct stored_bitmap *xor_with,
174                                           int flags)
175 {
176         struct stored_bitmap *stored;
177         khiter_t hash_pos;
178         int ret;
179
180         stored = xmalloc(sizeof(struct stored_bitmap));
181         stored->root = root;
182         stored->xor = xor_with;
183         stored->flags = flags;
184         hashcpy(stored->sha1, sha1);
185
186         hash_pos = kh_put_sha1(index->bitmaps, stored->sha1, &ret);
187
188         /* a 0 return code means the insertion succeeded with no changes,
189          * because the SHA1 already existed on the map. this is bad, there
190          * shouldn't be duplicated commits in the index */
191         if (ret == 0) {
192                 error("Duplicate entry in bitmap index: %s", sha1_to_hex(sha1));
193                 return NULL;
194         }
195
196         kh_value(index->bitmaps, hash_pos) = stored;
197         return stored;
198 }
199
200 static inline uint32_t read_be32(const unsigned char *buffer, size_t *pos)
201 {
202         uint32_t result = get_be32(buffer + *pos);
203         (*pos) += sizeof(result);
204         return result;
205 }
206
207 static inline uint8_t read_u8(const unsigned char *buffer, size_t *pos)
208 {
209         return buffer[(*pos)++];
210 }
211
212 #define MAX_XOR_OFFSET 160
213
214 static int load_bitmap_entries_v1(struct bitmap_index *index)
215 {
216         uint32_t i;
217         struct stored_bitmap *recent_bitmaps[MAX_XOR_OFFSET] = { NULL };
218
219         for (i = 0; i < index->entry_count; ++i) {
220                 int xor_offset, flags;
221                 struct ewah_bitmap *bitmap = NULL;
222                 struct stored_bitmap *xor_bitmap = NULL;
223                 uint32_t commit_idx_pos;
224                 const unsigned char *sha1;
225
226                 commit_idx_pos = read_be32(index->map, &index->map_pos);
227                 xor_offset = read_u8(index->map, &index->map_pos);
228                 flags = read_u8(index->map, &index->map_pos);
229
230                 sha1 = nth_packed_object_sha1(index->pack, commit_idx_pos);
231
232                 bitmap = read_bitmap_1(index);
233                 if (!bitmap)
234                         return -1;
235
236                 if (xor_offset > MAX_XOR_OFFSET || xor_offset > i)
237                         return error("Corrupted bitmap pack index");
238
239                 if (xor_offset > 0) {
240                         xor_bitmap = recent_bitmaps[(i - xor_offset) % MAX_XOR_OFFSET];
241
242                         if (xor_bitmap == NULL)
243                                 return error("Invalid XOR offset in bitmap pack index");
244                 }
245
246                 recent_bitmaps[i % MAX_XOR_OFFSET] = store_bitmap(
247                         index, bitmap, sha1, xor_bitmap, flags);
248         }
249
250         return 0;
251 }
252
253 static char *pack_bitmap_filename(struct packed_git *p)
254 {
255         size_t len;
256
257         if (!strip_suffix(p->pack_name, ".pack", &len))
258                 BUG("pack_name does not end in .pack");
259         return xstrfmt("%.*s.bitmap", (int)len, p->pack_name);
260 }
261
262 static int open_pack_bitmap_1(struct bitmap_index *bitmap_git, struct packed_git *packfile)
263 {
264         int fd;
265         struct stat st;
266         char *idx_name;
267
268         if (open_pack_index(packfile))
269                 return -1;
270
271         idx_name = pack_bitmap_filename(packfile);
272         fd = git_open(idx_name);
273         free(idx_name);
274
275         if (fd < 0)
276                 return -1;
277
278         if (fstat(fd, &st)) {
279                 close(fd);
280                 return -1;
281         }
282
283         if (bitmap_git->pack) {
284                 warning("ignoring extra bitmap file: %s", packfile->pack_name);
285                 close(fd);
286                 return -1;
287         }
288
289         bitmap_git->pack = packfile;
290         bitmap_git->map_size = xsize_t(st.st_size);
291         bitmap_git->map = xmmap(NULL, bitmap_git->map_size, PROT_READ, MAP_PRIVATE, fd, 0);
292         bitmap_git->map_pos = 0;
293         close(fd);
294
295         if (load_bitmap_header(bitmap_git) < 0) {
296                 munmap(bitmap_git->map, bitmap_git->map_size);
297                 bitmap_git->map = NULL;
298                 bitmap_git->map_size = 0;
299                 return -1;
300         }
301
302         return 0;
303 }
304
305 static int load_pack_bitmap(struct bitmap_index *bitmap_git)
306 {
307         assert(bitmap_git->map);
308
309         bitmap_git->bitmaps = kh_init_sha1();
310         bitmap_git->ext_index.positions = kh_init_sha1_pos();
311         load_pack_revindex(bitmap_git->pack);
312
313         if (!(bitmap_git->commits = read_bitmap_1(bitmap_git)) ||
314                 !(bitmap_git->trees = read_bitmap_1(bitmap_git)) ||
315                 !(bitmap_git->blobs = read_bitmap_1(bitmap_git)) ||
316                 !(bitmap_git->tags = read_bitmap_1(bitmap_git)))
317                 goto failed;
318
319         if (load_bitmap_entries_v1(bitmap_git) < 0)
320                 goto failed;
321
322         return 0;
323
324 failed:
325         munmap(bitmap_git->map, bitmap_git->map_size);
326         bitmap_git->map = NULL;
327         bitmap_git->map_size = 0;
328         return -1;
329 }
330
331 static int open_pack_bitmap(struct bitmap_index *bitmap_git)
332 {
333         struct packed_git *p;
334         int ret = -1;
335
336         assert(!bitmap_git->map);
337
338         for (p = get_all_packs(the_repository); p; p = p->next) {
339                 if (open_pack_bitmap_1(bitmap_git, p) == 0)
340                         ret = 0;
341         }
342
343         return ret;
344 }
345
346 struct bitmap_index *prepare_bitmap_git(void)
347 {
348         struct bitmap_index *bitmap_git = xcalloc(1, sizeof(*bitmap_git));
349
350         if (!open_pack_bitmap(bitmap_git) && !load_pack_bitmap(bitmap_git))
351                 return bitmap_git;
352
353         free_bitmap_index(bitmap_git);
354         return NULL;
355 }
356
357 struct include_data {
358         struct bitmap_index *bitmap_git;
359         struct bitmap *base;
360         struct bitmap *seen;
361 };
362
363 static inline int bitmap_position_extended(struct bitmap_index *bitmap_git,
364                                            const unsigned char *sha1)
365 {
366         khash_sha1_pos *positions = bitmap_git->ext_index.positions;
367         khiter_t pos = kh_get_sha1_pos(positions, sha1);
368
369         if (pos < kh_end(positions)) {
370                 int bitmap_pos = kh_value(positions, pos);
371                 return bitmap_pos + bitmap_git->pack->num_objects;
372         }
373
374         return -1;
375 }
376
377 static inline int bitmap_position_packfile(struct bitmap_index *bitmap_git,
378                                            const unsigned char *sha1)
379 {
380         off_t offset = find_pack_entry_one(sha1, bitmap_git->pack);
381         if (!offset)
382                 return -1;
383
384         return find_revindex_position(bitmap_git->pack, offset);
385 }
386
387 static int bitmap_position(struct bitmap_index *bitmap_git,
388                            const unsigned char *sha1)
389 {
390         int pos = bitmap_position_packfile(bitmap_git, sha1);
391         return (pos >= 0) ? pos : bitmap_position_extended(bitmap_git, sha1);
392 }
393
394 static int ext_index_add_object(struct bitmap_index *bitmap_git,
395                                 struct object *object, const char *name)
396 {
397         struct eindex *eindex = &bitmap_git->ext_index;
398
399         khiter_t hash_pos;
400         int hash_ret;
401         int bitmap_pos;
402
403         hash_pos = kh_put_sha1_pos(eindex->positions, object->oid.hash, &hash_ret);
404         if (hash_ret > 0) {
405                 if (eindex->count >= eindex->alloc) {
406                         eindex->alloc = (eindex->alloc + 16) * 3 / 2;
407                         REALLOC_ARRAY(eindex->objects, eindex->alloc);
408                         REALLOC_ARRAY(eindex->hashes, eindex->alloc);
409                 }
410
411                 bitmap_pos = eindex->count;
412                 eindex->objects[eindex->count] = object;
413                 eindex->hashes[eindex->count] = pack_name_hash(name);
414                 kh_value(eindex->positions, hash_pos) = bitmap_pos;
415                 eindex->count++;
416         } else {
417                 bitmap_pos = kh_value(eindex->positions, hash_pos);
418         }
419
420         return bitmap_pos + bitmap_git->pack->num_objects;
421 }
422
423 struct bitmap_show_data {
424         struct bitmap_index *bitmap_git;
425         struct bitmap *base;
426 };
427
428 static void show_object(struct object *object, const char *name, void *data_)
429 {
430         struct bitmap_show_data *data = data_;
431         int bitmap_pos;
432
433         bitmap_pos = bitmap_position(data->bitmap_git, object->oid.hash);
434
435         if (bitmap_pos < 0)
436                 bitmap_pos = ext_index_add_object(data->bitmap_git, object,
437                                                   name);
438
439         bitmap_set(data->base, bitmap_pos);
440 }
441
442 static void show_commit(struct commit *commit, void *data)
443 {
444 }
445
446 static int add_to_include_set(struct bitmap_index *bitmap_git,
447                               struct include_data *data,
448                               const unsigned char *sha1,
449                               int bitmap_pos)
450 {
451         khiter_t hash_pos;
452
453         if (data->seen && bitmap_get(data->seen, bitmap_pos))
454                 return 0;
455
456         if (bitmap_get(data->base, bitmap_pos))
457                 return 0;
458
459         hash_pos = kh_get_sha1(bitmap_git->bitmaps, sha1);
460         if (hash_pos < kh_end(bitmap_git->bitmaps)) {
461                 struct stored_bitmap *st = kh_value(bitmap_git->bitmaps, hash_pos);
462                 bitmap_or_ewah(data->base, lookup_stored_bitmap(st));
463                 return 0;
464         }
465
466         bitmap_set(data->base, bitmap_pos);
467         return 1;
468 }
469
470 static int should_include(struct commit *commit, void *_data)
471 {
472         struct include_data *data = _data;
473         int bitmap_pos;
474
475         bitmap_pos = bitmap_position(data->bitmap_git, commit->object.oid.hash);
476         if (bitmap_pos < 0)
477                 bitmap_pos = ext_index_add_object(data->bitmap_git,
478                                                   (struct object *)commit,
479                                                   NULL);
480
481         if (!add_to_include_set(data->bitmap_git, data, commit->object.oid.hash,
482                                 bitmap_pos)) {
483                 struct commit_list *parent = commit->parents;
484
485                 while (parent) {
486                         parent->item->object.flags |= SEEN;
487                         parent = parent->next;
488                 }
489
490                 return 0;
491         }
492
493         return 1;
494 }
495
496 static struct bitmap *find_objects(struct bitmap_index *bitmap_git,
497                                    struct rev_info *revs,
498                                    struct object_list *roots,
499                                    struct bitmap *seen)
500 {
501         struct bitmap *base = NULL;
502         int needs_walk = 0;
503
504         struct object_list *not_mapped = NULL;
505
506         /*
507          * Go through all the roots for the walk. The ones that have bitmaps
508          * on the bitmap index will be `or`ed together to form an initial
509          * global reachability analysis.
510          *
511          * The ones without bitmaps in the index will be stored in the
512          * `not_mapped_list` for further processing.
513          */
514         while (roots) {
515                 struct object *object = roots->item;
516                 roots = roots->next;
517
518                 if (object->type == OBJ_COMMIT) {
519                         khiter_t pos = kh_get_sha1(bitmap_git->bitmaps, object->oid.hash);
520
521                         if (pos < kh_end(bitmap_git->bitmaps)) {
522                                 struct stored_bitmap *st = kh_value(bitmap_git->bitmaps, pos);
523                                 struct ewah_bitmap *or_with = lookup_stored_bitmap(st);
524
525                                 if (base == NULL)
526                                         base = ewah_to_bitmap(or_with);
527                                 else
528                                         bitmap_or_ewah(base, or_with);
529
530                                 object->flags |= SEEN;
531                                 continue;
532                         }
533                 }
534
535                 object_list_insert(object, &not_mapped);
536         }
537
538         /*
539          * Best case scenario: We found bitmaps for all the roots,
540          * so the resulting `or` bitmap has the full reachability analysis
541          */
542         if (not_mapped == NULL)
543                 return base;
544
545         roots = not_mapped;
546
547         /*
548          * Let's iterate through all the roots that don't have bitmaps to
549          * check if we can determine them to be reachable from the existing
550          * global bitmap.
551          *
552          * If we cannot find them in the existing global bitmap, we'll need
553          * to push them to an actual walk and run it until we can confirm
554          * they are reachable
555          */
556         while (roots) {
557                 struct object *object = roots->item;
558                 int pos;
559
560                 roots = roots->next;
561                 pos = bitmap_position(bitmap_git, object->oid.hash);
562
563                 if (pos < 0 || base == NULL || !bitmap_get(base, pos)) {
564                         object->flags &= ~UNINTERESTING;
565                         add_pending_object(revs, object, "");
566                         needs_walk = 1;
567                 } else {
568                         object->flags |= SEEN;
569                 }
570         }
571
572         if (needs_walk) {
573                 struct include_data incdata;
574                 struct bitmap_show_data show_data;
575
576                 if (base == NULL)
577                         base = bitmap_new();
578
579                 incdata.bitmap_git = bitmap_git;
580                 incdata.base = base;
581                 incdata.seen = seen;
582
583                 revs->include_check = should_include;
584                 revs->include_check_data = &incdata;
585
586                 if (prepare_revision_walk(revs))
587                         die("revision walk setup failed");
588
589                 show_data.bitmap_git = bitmap_git;
590                 show_data.base = base;
591
592                 traverse_commit_list(revs, show_commit, show_object,
593                                      &show_data);
594         }
595
596         return base;
597 }
598
599 static void show_extended_objects(struct bitmap_index *bitmap_git,
600                                   show_reachable_fn show_reach)
601 {
602         struct bitmap *objects = bitmap_git->result;
603         struct eindex *eindex = &bitmap_git->ext_index;
604         uint32_t i;
605
606         for (i = 0; i < eindex->count; ++i) {
607                 struct object *obj;
608
609                 if (!bitmap_get(objects, bitmap_git->pack->num_objects + i))
610                         continue;
611
612                 obj = eindex->objects[i];
613                 show_reach(&obj->oid, obj->type, 0, eindex->hashes[i], NULL, 0);
614         }
615 }
616
617 static void show_objects_for_type(
618         struct bitmap_index *bitmap_git,
619         struct ewah_bitmap *type_filter,
620         enum object_type object_type,
621         show_reachable_fn show_reach)
622 {
623         size_t pos = 0, i = 0;
624         uint32_t offset;
625
626         struct ewah_iterator it;
627         eword_t filter;
628
629         struct bitmap *objects = bitmap_git->result;
630
631         if (bitmap_git->reuse_objects == bitmap_git->pack->num_objects)
632                 return;
633
634         ewah_iterator_init(&it, type_filter);
635
636         while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
637                 eword_t word = objects->words[i] & filter;
638
639                 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
640                         struct object_id oid;
641                         struct revindex_entry *entry;
642                         uint32_t hash = 0;
643
644                         if ((word >> offset) == 0)
645                                 break;
646
647                         offset += ewah_bit_ctz64(word >> offset);
648
649                         if (pos + offset < bitmap_git->reuse_objects)
650                                 continue;
651
652                         entry = &bitmap_git->pack->revindex[pos + offset];
653                         nth_packed_object_oid(&oid, bitmap_git->pack, entry->nr);
654
655                         if (bitmap_git->hashes)
656                                 hash = get_be32(bitmap_git->hashes + entry->nr);
657
658                         show_reach(&oid, object_type, 0, hash, bitmap_git->pack, entry->offset);
659                 }
660
661                 pos += BITS_IN_EWORD;
662                 i++;
663         }
664 }
665
666 static int in_bitmapped_pack(struct bitmap_index *bitmap_git,
667                              struct object_list *roots)
668 {
669         while (roots) {
670                 struct object *object = roots->item;
671                 roots = roots->next;
672
673                 if (find_pack_entry_one(object->oid.hash, bitmap_git->pack) > 0)
674                         return 1;
675         }
676
677         return 0;
678 }
679
680 struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs)
681 {
682         unsigned int i;
683
684         struct object_list *wants = NULL;
685         struct object_list *haves = NULL;
686
687         struct bitmap *wants_bitmap = NULL;
688         struct bitmap *haves_bitmap = NULL;
689
690         struct bitmap_index *bitmap_git = xcalloc(1, sizeof(*bitmap_git));
691         /* try to open a bitmapped pack, but don't parse it yet
692          * because we may not need to use it */
693         if (open_pack_bitmap(bitmap_git) < 0)
694                 goto cleanup;
695
696         for (i = 0; i < revs->pending.nr; ++i) {
697                 struct object *object = revs->pending.objects[i].item;
698
699                 if (object->type == OBJ_NONE)
700                         parse_object_or_die(&object->oid, NULL);
701
702                 while (object->type == OBJ_TAG) {
703                         struct tag *tag = (struct tag *) object;
704
705                         if (object->flags & UNINTERESTING)
706                                 object_list_insert(object, &haves);
707                         else
708                                 object_list_insert(object, &wants);
709
710                         if (!tag->tagged)
711                                 die("bad tag");
712                         object = parse_object_or_die(&tag->tagged->oid, NULL);
713                 }
714
715                 if (object->flags & UNINTERESTING)
716                         object_list_insert(object, &haves);
717                 else
718                         object_list_insert(object, &wants);
719         }
720
721         /*
722          * if we have a HAVES list, but none of those haves is contained
723          * in the packfile that has a bitmap, we don't have anything to
724          * optimize here
725          */
726         if (haves && !in_bitmapped_pack(bitmap_git, haves))
727                 goto cleanup;
728
729         /* if we don't want anything, we're done here */
730         if (!wants)
731                 goto cleanup;
732
733         /*
734          * now we're going to use bitmaps, so load the actual bitmap entries
735          * from disk. this is the point of no return; after this the rev_list
736          * becomes invalidated and we must perform the revwalk through bitmaps
737          */
738         if (load_pack_bitmap(bitmap_git) < 0)
739                 goto cleanup;
740
741         object_array_clear(&revs->pending);
742
743         if (haves) {
744                 revs->ignore_missing_links = 1;
745                 haves_bitmap = find_objects(bitmap_git, revs, haves, NULL);
746                 reset_revision_walk();
747                 revs->ignore_missing_links = 0;
748
749                 if (haves_bitmap == NULL)
750                         BUG("failed to perform bitmap walk");
751         }
752
753         wants_bitmap = find_objects(bitmap_git, revs, wants, haves_bitmap);
754
755         if (!wants_bitmap)
756                 BUG("failed to perform bitmap walk");
757
758         if (haves_bitmap)
759                 bitmap_and_not(wants_bitmap, haves_bitmap);
760
761         bitmap_git->result = wants_bitmap;
762         bitmap_git->haves = haves_bitmap;
763
764         return bitmap_git;
765
766 cleanup:
767         free_bitmap_index(bitmap_git);
768         return NULL;
769 }
770
771 int reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,
772                                        struct packed_git **packfile,
773                                        uint32_t *entries,
774                                        off_t *up_to)
775 {
776         /*
777          * Reuse the packfile content if we need more than
778          * 90% of its objects
779          */
780         static const double REUSE_PERCENT = 0.9;
781
782         struct bitmap *result = bitmap_git->result;
783         uint32_t reuse_threshold;
784         uint32_t i, reuse_objects = 0;
785
786         assert(result);
787
788         for (i = 0; i < result->word_alloc; ++i) {
789                 if (result->words[i] != (eword_t)~0) {
790                         reuse_objects += ewah_bit_ctz64(~result->words[i]);
791                         break;
792                 }
793
794                 reuse_objects += BITS_IN_EWORD;
795         }
796
797 #ifdef GIT_BITMAP_DEBUG
798         {
799                 const unsigned char *sha1;
800                 struct revindex_entry *entry;
801
802                 entry = &bitmap_git->reverse_index->revindex[reuse_objects];
803                 sha1 = nth_packed_object_sha1(bitmap_git->pack, entry->nr);
804
805                 fprintf(stderr, "Failed to reuse at %d (%016llx)\n",
806                         reuse_objects, result->words[i]);
807                 fprintf(stderr, " %s\n", sha1_to_hex(sha1));
808         }
809 #endif
810
811         if (!reuse_objects)
812                 return -1;
813
814         if (reuse_objects >= bitmap_git->pack->num_objects) {
815                 bitmap_git->reuse_objects = *entries = bitmap_git->pack->num_objects;
816                 *up_to = -1; /* reuse the full pack */
817                 *packfile = bitmap_git->pack;
818                 return 0;
819         }
820
821         reuse_threshold = bitmap_popcount(bitmap_git->result) * REUSE_PERCENT;
822
823         if (reuse_objects < reuse_threshold)
824                 return -1;
825
826         bitmap_git->reuse_objects = *entries = reuse_objects;
827         *up_to = bitmap_git->pack->revindex[reuse_objects].offset;
828         *packfile = bitmap_git->pack;
829
830         return 0;
831 }
832
833 void traverse_bitmap_commit_list(struct bitmap_index *bitmap_git,
834                                  show_reachable_fn show_reachable)
835 {
836         assert(bitmap_git->result);
837
838         show_objects_for_type(bitmap_git, bitmap_git->commits,
839                 OBJ_COMMIT, show_reachable);
840         show_objects_for_type(bitmap_git, bitmap_git->trees,
841                 OBJ_TREE, show_reachable);
842         show_objects_for_type(bitmap_git, bitmap_git->blobs,
843                 OBJ_BLOB, show_reachable);
844         show_objects_for_type(bitmap_git, bitmap_git->tags,
845                 OBJ_TAG, show_reachable);
846
847         show_extended_objects(bitmap_git, show_reachable);
848 }
849
850 static uint32_t count_object_type(struct bitmap_index *bitmap_git,
851                                   enum object_type type)
852 {
853         struct bitmap *objects = bitmap_git->result;
854         struct eindex *eindex = &bitmap_git->ext_index;
855
856         uint32_t i = 0, count = 0;
857         struct ewah_iterator it;
858         eword_t filter;
859
860         switch (type) {
861         case OBJ_COMMIT:
862                 ewah_iterator_init(&it, bitmap_git->commits);
863                 break;
864
865         case OBJ_TREE:
866                 ewah_iterator_init(&it, bitmap_git->trees);
867                 break;
868
869         case OBJ_BLOB:
870                 ewah_iterator_init(&it, bitmap_git->blobs);
871                 break;
872
873         case OBJ_TAG:
874                 ewah_iterator_init(&it, bitmap_git->tags);
875                 break;
876
877         default:
878                 return 0;
879         }
880
881         while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
882                 eword_t word = objects->words[i++] & filter;
883                 count += ewah_bit_popcount64(word);
884         }
885
886         for (i = 0; i < eindex->count; ++i) {
887                 if (eindex->objects[i]->type == type &&
888                         bitmap_get(objects, bitmap_git->pack->num_objects + i))
889                         count++;
890         }
891
892         return count;
893 }
894
895 void count_bitmap_commit_list(struct bitmap_index *bitmap_git,
896                               uint32_t *commits, uint32_t *trees,
897                               uint32_t *blobs, uint32_t *tags)
898 {
899         assert(bitmap_git->result);
900
901         if (commits)
902                 *commits = count_object_type(bitmap_git, OBJ_COMMIT);
903
904         if (trees)
905                 *trees = count_object_type(bitmap_git, OBJ_TREE);
906
907         if (blobs)
908                 *blobs = count_object_type(bitmap_git, OBJ_BLOB);
909
910         if (tags)
911                 *tags = count_object_type(bitmap_git, OBJ_TAG);
912 }
913
914 struct bitmap_test_data {
915         struct bitmap_index *bitmap_git;
916         struct bitmap *base;
917         struct progress *prg;
918         size_t seen;
919 };
920
921 static void test_show_object(struct object *object, const char *name,
922                              void *data)
923 {
924         struct bitmap_test_data *tdata = data;
925         int bitmap_pos;
926
927         bitmap_pos = bitmap_position(tdata->bitmap_git, object->oid.hash);
928         if (bitmap_pos < 0)
929                 die("Object not in bitmap: %s\n", oid_to_hex(&object->oid));
930
931         bitmap_set(tdata->base, bitmap_pos);
932         display_progress(tdata->prg, ++tdata->seen);
933 }
934
935 static void test_show_commit(struct commit *commit, void *data)
936 {
937         struct bitmap_test_data *tdata = data;
938         int bitmap_pos;
939
940         bitmap_pos = bitmap_position(tdata->bitmap_git,
941                                      commit->object.oid.hash);
942         if (bitmap_pos < 0)
943                 die("Object not in bitmap: %s\n", oid_to_hex(&commit->object.oid));
944
945         bitmap_set(tdata->base, bitmap_pos);
946         display_progress(tdata->prg, ++tdata->seen);
947 }
948
949 void test_bitmap_walk(struct rev_info *revs)
950 {
951         struct object *root;
952         struct bitmap *result = NULL;
953         khiter_t pos;
954         size_t result_popcnt;
955         struct bitmap_test_data tdata;
956         struct bitmap_index *bitmap_git;
957
958         if (!(bitmap_git = prepare_bitmap_git()))
959                 die("failed to load bitmap indexes");
960
961         if (revs->pending.nr != 1)
962                 die("you must specify exactly one commit to test");
963
964         fprintf(stderr, "Bitmap v%d test (%d entries loaded)\n",
965                 bitmap_git->version, bitmap_git->entry_count);
966
967         root = revs->pending.objects[0].item;
968         pos = kh_get_sha1(bitmap_git->bitmaps, root->oid.hash);
969
970         if (pos < kh_end(bitmap_git->bitmaps)) {
971                 struct stored_bitmap *st = kh_value(bitmap_git->bitmaps, pos);
972                 struct ewah_bitmap *bm = lookup_stored_bitmap(st);
973
974                 fprintf(stderr, "Found bitmap for %s. %d bits / %08x checksum\n",
975                         oid_to_hex(&root->oid), (int)bm->bit_size, ewah_checksum(bm));
976
977                 result = ewah_to_bitmap(bm);
978         }
979
980         if (result == NULL)
981                 die("Commit %s doesn't have an indexed bitmap", oid_to_hex(&root->oid));
982
983         revs->tag_objects = 1;
984         revs->tree_objects = 1;
985         revs->blob_objects = 1;
986
987         result_popcnt = bitmap_popcount(result);
988
989         if (prepare_revision_walk(revs))
990                 die("revision walk setup failed");
991
992         tdata.bitmap_git = bitmap_git;
993         tdata.base = bitmap_new();
994         tdata.prg = start_progress("Verifying bitmap entries", result_popcnt);
995         tdata.seen = 0;
996
997         traverse_commit_list(revs, &test_show_commit, &test_show_object, &tdata);
998
999         stop_progress(&tdata.prg);
1000
1001         if (bitmap_equals(result, tdata.base))
1002                 fprintf(stderr, "OK!\n");
1003         else
1004                 fprintf(stderr, "Mismatch!\n");
1005
1006         free_bitmap_index(bitmap_git);
1007 }
1008
1009 static int rebuild_bitmap(uint32_t *reposition,
1010                           struct ewah_bitmap *source,
1011                           struct bitmap *dest)
1012 {
1013         uint32_t pos = 0;
1014         struct ewah_iterator it;
1015         eword_t word;
1016
1017         ewah_iterator_init(&it, source);
1018
1019         while (ewah_iterator_next(&word, &it)) {
1020                 uint32_t offset, bit_pos;
1021
1022                 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
1023                         if ((word >> offset) == 0)
1024                                 break;
1025
1026                         offset += ewah_bit_ctz64(word >> offset);
1027
1028                         bit_pos = reposition[pos + offset];
1029                         if (bit_pos > 0)
1030                                 bitmap_set(dest, bit_pos - 1);
1031                         else /* can't reuse, we don't have the object */
1032                                 return -1;
1033                 }
1034
1035                 pos += BITS_IN_EWORD;
1036         }
1037         return 0;
1038 }
1039
1040 int rebuild_existing_bitmaps(struct bitmap_index *bitmap_git,
1041                              struct packing_data *mapping,
1042                              khash_sha1 *reused_bitmaps,
1043                              int show_progress)
1044 {
1045         uint32_t i, num_objects;
1046         uint32_t *reposition;
1047         struct bitmap *rebuild;
1048         struct stored_bitmap *stored;
1049         struct progress *progress = NULL;
1050
1051         khiter_t hash_pos;
1052         int hash_ret;
1053
1054         num_objects = bitmap_git->pack->num_objects;
1055         reposition = xcalloc(num_objects, sizeof(uint32_t));
1056
1057         for (i = 0; i < num_objects; ++i) {
1058                 const unsigned char *sha1;
1059                 struct revindex_entry *entry;
1060                 struct object_entry *oe;
1061
1062                 entry = &bitmap_git->pack->revindex[i];
1063                 sha1 = nth_packed_object_sha1(bitmap_git->pack, entry->nr);
1064                 oe = packlist_find(mapping, sha1, NULL);
1065
1066                 if (oe)
1067                         reposition[i] = oe_in_pack_pos(mapping, oe) + 1;
1068         }
1069
1070         rebuild = bitmap_new();
1071         i = 0;
1072
1073         if (show_progress)
1074                 progress = start_progress("Reusing bitmaps", 0);
1075
1076         kh_foreach_value(bitmap_git->bitmaps, stored, {
1077                 if (stored->flags & BITMAP_FLAG_REUSE) {
1078                         if (!rebuild_bitmap(reposition,
1079                                             lookup_stored_bitmap(stored),
1080                                             rebuild)) {
1081                                 hash_pos = kh_put_sha1(reused_bitmaps,
1082                                                        stored->sha1,
1083                                                        &hash_ret);
1084                                 kh_value(reused_bitmaps, hash_pos) =
1085                                         bitmap_to_ewah(rebuild);
1086                         }
1087                         bitmap_reset(rebuild);
1088                         display_progress(progress, ++i);
1089                 }
1090         });
1091
1092         stop_progress(&progress);
1093
1094         free(reposition);
1095         bitmap_free(rebuild);
1096         return 0;
1097 }
1098
1099 void free_bitmap_index(struct bitmap_index *b)
1100 {
1101         if (!b)
1102                 return;
1103
1104         if (b->map)
1105                 munmap(b->map, b->map_size);
1106         ewah_pool_free(b->commits);
1107         ewah_pool_free(b->trees);
1108         ewah_pool_free(b->blobs);
1109         ewah_pool_free(b->tags);
1110         kh_destroy_sha1(b->bitmaps);
1111         free(b->ext_index.objects);
1112         free(b->ext_index.hashes);
1113         bitmap_free(b->result);
1114         bitmap_free(b->haves);
1115         free(b);
1116 }
1117
1118 int bitmap_has_sha1_in_uninteresting(struct bitmap_index *bitmap_git,
1119                                      const unsigned char *sha1)
1120 {
1121         int pos;
1122
1123         if (!bitmap_git)
1124                 return 0; /* no bitmap loaded */
1125         if (!bitmap_git->haves)
1126                 return 0; /* walk had no "haves" */
1127
1128         pos = bitmap_position_packfile(bitmap_git, sha1);
1129         if (pos < 0)
1130                 return 0;
1131
1132         return bitmap_get(bitmap_git->haves, pos);
1133 }