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
16struct 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
25struct 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[20];
41};
42
43static struct bitmap_writer writer;
44
45void 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 */
53void 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(the_repository,
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 */
113static struct object **seen_objects;
114static unsigned int seen_objects_nr, seen_objects_alloc;
115
116static 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
130static 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
136static 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
145static 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
157static 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
164static void show_commit(struct commit *commit, void *data)
165{
166 mark_as_seen((struct object *)commit);
167}
168
169static int
170add_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
189static int
190should_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
211static 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
251void 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 init_revisions(&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 */
332static 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
356static 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
363void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack)
364{
365 if (prepare_bitmap_git() < 0)
366 return;
367
368 writer.reused = kh_init_sha1();
369 rebuild_existing_bitmaps(to_pack, writer.reused, writer.show_progress);
370}
371
372static struct ewah_bitmap *find_reused_bitmap(const unsigned char *sha1)
373{
374 khiter_t hash_pos;
375
376 if (!writer.reused)
377 return NULL;
378
379 hash_pos = kh_get_sha1(writer.reused, sha1);
380 if (hash_pos >= kh_end(writer.reused))
381 return NULL;
382
383 return kh_value(writer.reused, hash_pos);
384}
385
386void bitmap_writer_select_commits(struct commit **indexed_commits,
387 unsigned int indexed_commits_nr,
388 int max_bitmaps)
389{
390 unsigned int i = 0, j, next;
391
392 QSORT(indexed_commits, indexed_commits_nr, date_compare);
393
394 if (writer.show_progress)
395 writer.progress = start_progress("Selecting bitmap commits", 0);
396
397 if (indexed_commits_nr < 100) {
398 for (i = 0; i < indexed_commits_nr; ++i)
399 push_bitmapped_commit(indexed_commits[i], NULL);
400 return;
401 }
402
403 for (;;) {
404 struct ewah_bitmap *reused_bitmap = NULL;
405 struct commit *chosen = NULL;
406
407 next = next_commit_index(i);
408
409 if (i + next >= indexed_commits_nr)
410 break;
411
412 if (max_bitmaps > 0 && writer.selected_nr >= max_bitmaps) {
413 writer.selected_nr = max_bitmaps;
414 break;
415 }
416
417 if (next == 0) {
418 chosen = indexed_commits[i];
419 reused_bitmap = find_reused_bitmap(chosen->object.oid.hash);
420 } else {
421 chosen = indexed_commits[i + next];
422
423 for (j = 0; j <= next; ++j) {
424 struct commit *cm = indexed_commits[i + j];
425
426 reused_bitmap = find_reused_bitmap(cm->object.oid.hash);
427 if (reused_bitmap || (cm->object.flags & NEEDS_BITMAP) != 0) {
428 chosen = cm;
429 break;
430 }
431
432 if (cm->parents && cm->parents->next)
433 chosen = cm;
434 }
435 }
436
437 push_bitmapped_commit(chosen, reused_bitmap);
438
439 i += next + 1;
440 display_progress(writer.progress, i);
441 }
442
443 stop_progress(&writer.progress);
444}
445
446
447static int hashwrite_ewah_helper(void *f, const void *buf, size_t len)
448{
449 /* hashwrite will die on error */
450 hashwrite(f, buf, len);
451 return len;
452}
453
454/**
455 * Write the bitmap index to disk
456 */
457static inline void dump_bitmap(struct hashfile *f, struct ewah_bitmap *bitmap)
458{
459 if (ewah_serialize_to(bitmap, hashwrite_ewah_helper, f) < 0)
460 die("Failed to write bitmap index");
461}
462
463static const unsigned char *sha1_access(size_t pos, void *table)
464{
465 struct pack_idx_entry **index = table;
466 return index[pos]->oid.hash;
467}
468
469static void write_selected_commits_v1(struct hashfile *f,
470 struct pack_idx_entry **index,
471 uint32_t index_nr)
472{
473 int i;
474
475 for (i = 0; i < writer.selected_nr; ++i) {
476 struct bitmapped_commit *stored = &writer.selected[i];
477
478 int commit_pos =
479 sha1_pos(stored->commit->object.oid.hash, index, index_nr, sha1_access);
480
481 if (commit_pos < 0)
482 BUG("trying to write commit not in index");
483
484 hashwrite_be32(f, commit_pos);
485 hashwrite_u8(f, stored->xor_offset);
486 hashwrite_u8(f, stored->flags);
487
488 dump_bitmap(f, stored->write_as);
489 }
490}
491
492static void write_hash_cache(struct hashfile *f,
493 struct pack_idx_entry **index,
494 uint32_t index_nr)
495{
496 uint32_t i;
497
498 for (i = 0; i < index_nr; ++i) {
499 struct object_entry *entry = (struct object_entry *)index[i];
500 uint32_t hash_value = htonl(entry->hash);
501 hashwrite(f, &hash_value, sizeof(hash_value));
502 }
503}
504
505void bitmap_writer_set_checksum(unsigned char *sha1)
506{
507 hashcpy(writer.pack_checksum, sha1);
508}
509
510void bitmap_writer_finish(struct pack_idx_entry **index,
511 uint32_t index_nr,
512 const char *filename,
513 uint16_t options)
514{
515 static uint16_t default_version = 1;
516 static uint16_t flags = BITMAP_OPT_FULL_DAG;
517 struct strbuf tmp_file = STRBUF_INIT;
518 struct hashfile *f;
519
520 struct bitmap_disk_header header;
521
522 int fd = odb_mkstemp(&tmp_file, "pack/tmp_bitmap_XXXXXX");
523
524 f = hashfd(fd, tmp_file.buf);
525
526 memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
527 header.version = htons(default_version);
528 header.options = htons(flags | options);
529 header.entry_count = htonl(writer.selected_nr);
530 hashcpy(header.checksum, writer.pack_checksum);
531
532 hashwrite(f, &header, sizeof(header));
533 dump_bitmap(f, writer.commits);
534 dump_bitmap(f, writer.trees);
535 dump_bitmap(f, writer.blobs);
536 dump_bitmap(f, writer.tags);
537 write_selected_commits_v1(f, index, index_nr);
538
539 if (options & BITMAP_OPT_HASH_CACHE)
540 write_hash_cache(f, index, index_nr);
541
542 finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
543
544 if (adjust_shared_perm(tmp_file.buf))
545 die_errno("unable to make temporary bitmap file readable");
546
547 if (rename(tmp_file.buf, filename))
548 die_errno("unable to rename temporary bitmap file to '%s'", filename);
549
550 strbuf_release(&tmp_file);
551}