Merge branch 'tb/use-common-win32-pathfuncs-on-cygwin'
[git] / pack-bitmap-write.c
1 #include "cache.h"
2 #include "object-store.h"
3 #include "commit.h"
4 #include "tag.h"
5 #include "diff.h"
6 #include "revision.h"
7 #include "list-objects.h"
8 #include "progress.h"
9 #include "pack-revindex.h"
10 #include "pack.h"
11 #include "pack-bitmap.h"
12 #include "sha1-lookup.h"
13 #include "pack-objects.h"
14 #include "commit-reach.h"
15
16 struct bitmapped_commit {
17         struct commit *commit;
18         struct ewah_bitmap *bitmap;
19         struct ewah_bitmap *write_as;
20         int flags;
21         int xor_offset;
22         uint32_t commit_pos;
23 };
24
25 struct bitmap_writer {
26         struct ewah_bitmap *commits;
27         struct ewah_bitmap *trees;
28         struct ewah_bitmap *blobs;
29         struct ewah_bitmap *tags;
30
31         khash_sha1 *bitmaps;
32         khash_sha1 *reused;
33         struct packing_data *to_pack;
34
35         struct bitmapped_commit *selected;
36         unsigned int selected_nr, selected_alloc;
37
38         struct progress *progress;
39         int show_progress;
40         unsigned char pack_checksum[GIT_MAX_RAWSZ];
41 };
42
43 static struct bitmap_writer writer;
44
45 void bitmap_writer_show_progress(int show)
46 {
47         writer.show_progress = show;
48 }
49
50 /**
51  * Build the initial type index for the packfile
52  */
53 void bitmap_writer_build_type_index(struct packing_data *to_pack,
54                                     struct pack_idx_entry **index,
55                                     uint32_t index_nr)
56 {
57         uint32_t i;
58
59         writer.commits = ewah_new();
60         writer.trees = ewah_new();
61         writer.blobs = ewah_new();
62         writer.tags = ewah_new();
63         ALLOC_ARRAY(to_pack->in_pack_pos, to_pack->nr_objects);
64
65         for (i = 0; i < index_nr; ++i) {
66                 struct object_entry *entry = (struct object_entry *)index[i];
67                 enum object_type real_type;
68
69                 oe_set_in_pack_pos(to_pack, entry, i);
70
71                 switch (oe_type(entry)) {
72                 case OBJ_COMMIT:
73                 case OBJ_TREE:
74                 case OBJ_BLOB:
75                 case OBJ_TAG:
76                         real_type = oe_type(entry);
77                         break;
78
79                 default:
80                         real_type = oid_object_info(to_pack->repo,
81                                                     &entry->idx.oid, NULL);
82                         break;
83                 }
84
85                 switch (real_type) {
86                 case OBJ_COMMIT:
87                         ewah_set(writer.commits, i);
88                         break;
89
90                 case OBJ_TREE:
91                         ewah_set(writer.trees, i);
92                         break;
93
94                 case OBJ_BLOB:
95                         ewah_set(writer.blobs, i);
96                         break;
97
98                 case OBJ_TAG:
99                         ewah_set(writer.tags, i);
100                         break;
101
102                 default:
103                         die("Missing type information for %s (%d/%d)",
104                             oid_to_hex(&entry->idx.oid), real_type,
105                             oe_type(entry));
106                 }
107         }
108 }
109
110 /**
111  * Compute the actual bitmaps
112  */
113 static struct object **seen_objects;
114 static unsigned int seen_objects_nr, seen_objects_alloc;
115
116 static inline void push_bitmapped_commit(struct commit *commit, struct ewah_bitmap *reused)
117 {
118         if (writer.selected_nr >= writer.selected_alloc) {
119                 writer.selected_alloc = (writer.selected_alloc + 32) * 2;
120                 REALLOC_ARRAY(writer.selected, writer.selected_alloc);
121         }
122
123         writer.selected[writer.selected_nr].commit = commit;
124         writer.selected[writer.selected_nr].bitmap = reused;
125         writer.selected[writer.selected_nr].flags = 0;
126
127         writer.selected_nr++;
128 }
129
130 static inline void mark_as_seen(struct object *object)
131 {
132         ALLOC_GROW(seen_objects, seen_objects_nr + 1, seen_objects_alloc);
133         seen_objects[seen_objects_nr++] = object;
134 }
135
136 static inline void reset_all_seen(void)
137 {
138         unsigned int i;
139         for (i = 0; i < seen_objects_nr; ++i) {
140                 seen_objects[i]->flags &= ~(SEEN | ADDED | SHOWN);
141         }
142         seen_objects_nr = 0;
143 }
144
145 static uint32_t find_object_pos(const unsigned char *sha1)
146 {
147         struct object_entry *entry = packlist_find(writer.to_pack, sha1, NULL);
148
149         if (!entry) {
150                 die("Failed to write bitmap index. Packfile doesn't have full closure "
151                         "(object %s is missing)", sha1_to_hex(sha1));
152         }
153
154         return oe_in_pack_pos(writer.to_pack, entry);
155 }
156
157 static void show_object(struct object *object, const char *name, void *data)
158 {
159         struct bitmap *base = data;
160         bitmap_set(base, find_object_pos(object->oid.hash));
161         mark_as_seen(object);
162 }
163
164 static void show_commit(struct commit *commit, void *data)
165 {
166         mark_as_seen((struct object *)commit);
167 }
168
169 static int
170 add_to_include_set(struct bitmap *base, struct commit *commit)
171 {
172         khiter_t hash_pos;
173         uint32_t bitmap_pos = find_object_pos(commit->object.oid.hash);
174
175         if (bitmap_get(base, bitmap_pos))
176                 return 0;
177
178         hash_pos = kh_get_sha1(writer.bitmaps, commit->object.oid.hash);
179         if (hash_pos < kh_end(writer.bitmaps)) {
180                 struct bitmapped_commit *bc = kh_value(writer.bitmaps, hash_pos);
181                 bitmap_or_ewah(base, bc->bitmap);
182                 return 0;
183         }
184
185         bitmap_set(base, bitmap_pos);
186         return 1;
187 }
188
189 static int
190 should_include(struct commit *commit, void *_data)
191 {
192         struct bitmap *base = _data;
193
194         if (!add_to_include_set(base, commit)) {
195                 struct commit_list *parent = commit->parents;
196
197                 mark_as_seen((struct object *)commit);
198
199                 while (parent) {
200                         parent->item->object.flags |= SEEN;
201                         mark_as_seen((struct object *)parent->item);
202                         parent = parent->next;
203                 }
204
205                 return 0;
206         }
207
208         return 1;
209 }
210
211 static void compute_xor_offsets(void)
212 {
213         static const int MAX_XOR_OFFSET_SEARCH = 10;
214
215         int i, next = 0;
216
217         while (next < writer.selected_nr) {
218                 struct bitmapped_commit *stored = &writer.selected[next];
219
220                 int best_offset = 0;
221                 struct ewah_bitmap *best_bitmap = stored->bitmap;
222                 struct ewah_bitmap *test_xor;
223
224                 for (i = 1; i <= MAX_XOR_OFFSET_SEARCH; ++i) {
225                         int curr = next - i;
226
227                         if (curr < 0)
228                                 break;
229
230                         test_xor = ewah_pool_new();
231                         ewah_xor(writer.selected[curr].bitmap, stored->bitmap, test_xor);
232
233                         if (test_xor->buffer_size < best_bitmap->buffer_size) {
234                                 if (best_bitmap != stored->bitmap)
235                                         ewah_pool_free(best_bitmap);
236
237                                 best_bitmap = test_xor;
238                                 best_offset = i;
239                         } else {
240                                 ewah_pool_free(test_xor);
241                         }
242                 }
243
244                 stored->xor_offset = best_offset;
245                 stored->write_as = best_bitmap;
246
247                 next++;
248         }
249 }
250
251 void bitmap_writer_build(struct packing_data *to_pack)
252 {
253         static const double REUSE_BITMAP_THRESHOLD = 0.2;
254
255         int i, reuse_after, need_reset;
256         struct bitmap *base = bitmap_new();
257         struct rev_info revs;
258
259         writer.bitmaps = kh_init_sha1();
260         writer.to_pack = to_pack;
261
262         if (writer.show_progress)
263                 writer.progress = start_progress("Building bitmaps", writer.selected_nr);
264
265         repo_init_revisions(to_pack->repo, &revs, NULL);
266         revs.tag_objects = 1;
267         revs.tree_objects = 1;
268         revs.blob_objects = 1;
269         revs.no_walk = 0;
270
271         revs.include_check = should_include;
272         reset_revision_walk();
273
274         reuse_after = writer.selected_nr * REUSE_BITMAP_THRESHOLD;
275         need_reset = 0;
276
277         for (i = writer.selected_nr - 1; i >= 0; --i) {
278                 struct bitmapped_commit *stored;
279                 struct object *object;
280
281                 khiter_t hash_pos;
282                 int hash_ret;
283
284                 stored = &writer.selected[i];
285                 object = (struct object *)stored->commit;
286
287                 if (stored->bitmap == NULL) {
288                         if (i < writer.selected_nr - 1 &&
289                             (need_reset ||
290                              !in_merge_bases(writer.selected[i + 1].commit,
291                                              stored->commit))) {
292                             bitmap_reset(base);
293                             reset_all_seen();
294                         }
295
296                         add_pending_object(&revs, object, "");
297                         revs.include_check_data = base;
298
299                         if (prepare_revision_walk(&revs))
300                                 die("revision walk setup failed");
301
302                         traverse_commit_list(&revs, show_commit, show_object, base);
303
304                         object_array_clear(&revs.pending);
305
306                         stored->bitmap = bitmap_to_ewah(base);
307                         need_reset = 0;
308                 } else
309                         need_reset = 1;
310
311                 if (i >= reuse_after)
312                         stored->flags |= BITMAP_FLAG_REUSE;
313
314                 hash_pos = kh_put_sha1(writer.bitmaps, object->oid.hash, &hash_ret);
315                 if (hash_ret == 0)
316                         die("Duplicate entry when writing index: %s",
317                             oid_to_hex(&object->oid));
318
319                 kh_value(writer.bitmaps, hash_pos) = stored;
320                 display_progress(writer.progress, writer.selected_nr - i);
321         }
322
323         bitmap_free(base);
324         stop_progress(&writer.progress);
325
326         compute_xor_offsets();
327 }
328
329 /**
330  * Select the commits that will be bitmapped
331  */
332 static inline unsigned int next_commit_index(unsigned int idx)
333 {
334         static const unsigned int MIN_COMMITS = 100;
335         static const unsigned int MAX_COMMITS = 5000;
336
337         static const unsigned int MUST_REGION = 100;
338         static const unsigned int MIN_REGION = 20000;
339
340         unsigned int offset, next;
341
342         if (idx <= MUST_REGION)
343                 return 0;
344
345         if (idx <= MIN_REGION) {
346                 offset = idx - MUST_REGION;
347                 return (offset < MIN_COMMITS) ? offset : MIN_COMMITS;
348         }
349
350         offset = idx - MIN_REGION;
351         next = (offset < MAX_COMMITS) ? offset : MAX_COMMITS;
352
353         return (next > MIN_COMMITS) ? next : MIN_COMMITS;
354 }
355
356 static int date_compare(const void *_a, const void *_b)
357 {
358         struct commit *a = *(struct commit **)_a;
359         struct commit *b = *(struct commit **)_b;
360         return (long)b->date - (long)a->date;
361 }
362
363 void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack)
364 {
365         struct bitmap_index *bitmap_git;
366         if (!(bitmap_git = prepare_bitmap_git(to_pack->repo)))
367                 return;
368
369         writer.reused = kh_init_sha1();
370         rebuild_existing_bitmaps(bitmap_git, to_pack, writer.reused,
371                                  writer.show_progress);
372         /*
373          * NEEDSWORK: rebuild_existing_bitmaps() makes writer.reused reference
374          * some bitmaps in bitmap_git, so we can't free the latter.
375          */
376 }
377
378 static struct ewah_bitmap *find_reused_bitmap(const unsigned char *sha1)
379 {
380         khiter_t hash_pos;
381
382         if (!writer.reused)
383                 return NULL;
384
385         hash_pos = kh_get_sha1(writer.reused, sha1);
386         if (hash_pos >= kh_end(writer.reused))
387                 return NULL;
388
389         return kh_value(writer.reused, hash_pos);
390 }
391
392 void bitmap_writer_select_commits(struct commit **indexed_commits,
393                                   unsigned int indexed_commits_nr,
394                                   int max_bitmaps)
395 {
396         unsigned int i = 0, j, next;
397
398         QSORT(indexed_commits, indexed_commits_nr, date_compare);
399
400         if (writer.show_progress)
401                 writer.progress = start_progress("Selecting bitmap commits", 0);
402
403         if (indexed_commits_nr < 100) {
404                 for (i = 0; i < indexed_commits_nr; ++i)
405                         push_bitmapped_commit(indexed_commits[i], NULL);
406                 return;
407         }
408
409         for (;;) {
410                 struct ewah_bitmap *reused_bitmap = NULL;
411                 struct commit *chosen = NULL;
412
413                 next = next_commit_index(i);
414
415                 if (i + next >= indexed_commits_nr)
416                         break;
417
418                 if (max_bitmaps > 0 && writer.selected_nr >= max_bitmaps) {
419                         writer.selected_nr = max_bitmaps;
420                         break;
421                 }
422
423                 if (next == 0) {
424                         chosen = indexed_commits[i];
425                         reused_bitmap = find_reused_bitmap(chosen->object.oid.hash);
426                 } else {
427                         chosen = indexed_commits[i + next];
428
429                         for (j = 0; j <= next; ++j) {
430                                 struct commit *cm = indexed_commits[i + j];
431
432                                 reused_bitmap = find_reused_bitmap(cm->object.oid.hash);
433                                 if (reused_bitmap || (cm->object.flags & NEEDS_BITMAP) != 0) {
434                                         chosen = cm;
435                                         break;
436                                 }
437
438                                 if (cm->parents && cm->parents->next)
439                                         chosen = cm;
440                         }
441                 }
442
443                 push_bitmapped_commit(chosen, reused_bitmap);
444
445                 i += next + 1;
446                 display_progress(writer.progress, i);
447         }
448
449         stop_progress(&writer.progress);
450 }
451
452
453 static int hashwrite_ewah_helper(void *f, const void *buf, size_t len)
454 {
455         /* hashwrite will die on error */
456         hashwrite(f, buf, len);
457         return len;
458 }
459
460 /**
461  * Write the bitmap index to disk
462  */
463 static inline void dump_bitmap(struct hashfile *f, struct ewah_bitmap *bitmap)
464 {
465         if (ewah_serialize_to(bitmap, hashwrite_ewah_helper, f) < 0)
466                 die("Failed to write bitmap index");
467 }
468
469 static const unsigned char *sha1_access(size_t pos, void *table)
470 {
471         struct pack_idx_entry **index = table;
472         return index[pos]->oid.hash;
473 }
474
475 static void write_selected_commits_v1(struct hashfile *f,
476                                       struct pack_idx_entry **index,
477                                       uint32_t index_nr)
478 {
479         int i;
480
481         for (i = 0; i < writer.selected_nr; ++i) {
482                 struct bitmapped_commit *stored = &writer.selected[i];
483
484                 int commit_pos =
485                         sha1_pos(stored->commit->object.oid.hash, index, index_nr, sha1_access);
486
487                 if (commit_pos < 0)
488                         BUG("trying to write commit not in index");
489
490                 hashwrite_be32(f, commit_pos);
491                 hashwrite_u8(f, stored->xor_offset);
492                 hashwrite_u8(f, stored->flags);
493
494                 dump_bitmap(f, stored->write_as);
495         }
496 }
497
498 static void write_hash_cache(struct hashfile *f,
499                              struct pack_idx_entry **index,
500                              uint32_t index_nr)
501 {
502         uint32_t i;
503
504         for (i = 0; i < index_nr; ++i) {
505                 struct object_entry *entry = (struct object_entry *)index[i];
506                 uint32_t hash_value = htonl(entry->hash);
507                 hashwrite(f, &hash_value, sizeof(hash_value));
508         }
509 }
510
511 void bitmap_writer_set_checksum(unsigned char *sha1)
512 {
513         hashcpy(writer.pack_checksum, sha1);
514 }
515
516 void bitmap_writer_finish(struct pack_idx_entry **index,
517                           uint32_t index_nr,
518                           const char *filename,
519                           uint16_t options)
520 {
521         static uint16_t default_version = 1;
522         static uint16_t flags = BITMAP_OPT_FULL_DAG;
523         struct strbuf tmp_file = STRBUF_INIT;
524         struct hashfile *f;
525
526         struct bitmap_disk_header header;
527
528         int fd = odb_mkstemp(&tmp_file, "pack/tmp_bitmap_XXXXXX");
529
530         f = hashfd(fd, tmp_file.buf);
531
532         memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
533         header.version = htons(default_version);
534         header.options = htons(flags | options);
535         header.entry_count = htonl(writer.selected_nr);
536         hashcpy(header.checksum, writer.pack_checksum);
537
538         hashwrite(f, &header, sizeof(header));
539         dump_bitmap(f, writer.commits);
540         dump_bitmap(f, writer.trees);
541         dump_bitmap(f, writer.blobs);
542         dump_bitmap(f, writer.tags);
543         write_selected_commits_v1(f, index, index_nr);
544
545         if (options & BITMAP_OPT_HASH_CACHE)
546                 write_hash_cache(f, index, index_nr);
547
548         finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
549
550         if (adjust_shared_perm(tmp_file.buf))
551                 die_errno("unable to make temporary bitmap file readable");
552
553         if (rename(tmp_file.buf, filename))
554                 die_errno("unable to rename temporary bitmap file to '%s'", filename);
555
556         strbuf_release(&tmp_file);
557 }