Merge branch 'jc/strbuf-getline'
[git] / pack-bitmap-write.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "tag.h"
4 #include "diff.h"
5 #include "revision.h"
6 #include "list-objects.h"
7 #include "progress.h"
8 #include "pack-revindex.h"
9 #include "pack.h"
10 #include "pack-bitmap.h"
11 #include "sha1-lookup.h"
12 #include "pack-objects.h"
13
14 struct bitmapped_commit {
15         struct commit *commit;
16         struct ewah_bitmap *bitmap;
17         struct ewah_bitmap *write_as;
18         int flags;
19         int xor_offset;
20         uint32_t commit_pos;
21 };
22
23 struct bitmap_writer {
24         struct ewah_bitmap *commits;
25         struct ewah_bitmap *trees;
26         struct ewah_bitmap *blobs;
27         struct ewah_bitmap *tags;
28
29         khash_sha1 *bitmaps;
30         khash_sha1 *reused;
31         struct packing_data *to_pack;
32
33         struct bitmapped_commit *selected;
34         unsigned int selected_nr, selected_alloc;
35
36         struct progress *progress;
37         int show_progress;
38         unsigned char pack_checksum[20];
39 };
40
41 static struct bitmap_writer writer;
42
43 void bitmap_writer_show_progress(int show)
44 {
45         writer.show_progress = show;
46 }
47
48 /**
49  * Build the initial type index for the packfile
50  */
51 void bitmap_writer_build_type_index(struct pack_idx_entry **index,
52                                     uint32_t index_nr)
53 {
54         uint32_t i;
55
56         writer.commits = ewah_new();
57         writer.trees = ewah_new();
58         writer.blobs = ewah_new();
59         writer.tags = ewah_new();
60
61         for (i = 0; i < index_nr; ++i) {
62                 struct object_entry *entry = (struct object_entry *)index[i];
63                 enum object_type real_type;
64
65                 entry->in_pack_pos = i;
66
67                 switch (entry->type) {
68                 case OBJ_COMMIT:
69                 case OBJ_TREE:
70                 case OBJ_BLOB:
71                 case OBJ_TAG:
72                         real_type = entry->type;
73                         break;
74
75                 default:
76                         real_type = sha1_object_info(entry->idx.sha1, NULL);
77                         break;
78                 }
79
80                 switch (real_type) {
81                 case OBJ_COMMIT:
82                         ewah_set(writer.commits, i);
83                         break;
84
85                 case OBJ_TREE:
86                         ewah_set(writer.trees, i);
87                         break;
88
89                 case OBJ_BLOB:
90                         ewah_set(writer.blobs, i);
91                         break;
92
93                 case OBJ_TAG:
94                         ewah_set(writer.tags, i);
95                         break;
96
97                 default:
98                         die("Missing type information for %s (%d/%d)",
99                             sha1_to_hex(entry->idx.sha1), real_type, entry->type);
100                 }
101         }
102 }
103
104 /**
105  * Compute the actual bitmaps
106  */
107 static struct object **seen_objects;
108 static unsigned int seen_objects_nr, seen_objects_alloc;
109
110 static inline void push_bitmapped_commit(struct commit *commit, struct ewah_bitmap *reused)
111 {
112         if (writer.selected_nr >= writer.selected_alloc) {
113                 writer.selected_alloc = (writer.selected_alloc + 32) * 2;
114                 REALLOC_ARRAY(writer.selected, writer.selected_alloc);
115         }
116
117         writer.selected[writer.selected_nr].commit = commit;
118         writer.selected[writer.selected_nr].bitmap = reused;
119         writer.selected[writer.selected_nr].flags = 0;
120
121         writer.selected_nr++;
122 }
123
124 static inline void mark_as_seen(struct object *object)
125 {
126         ALLOC_GROW(seen_objects, seen_objects_nr + 1, seen_objects_alloc);
127         seen_objects[seen_objects_nr++] = object;
128 }
129
130 static inline void reset_all_seen(void)
131 {
132         unsigned int i;
133         for (i = 0; i < seen_objects_nr; ++i) {
134                 seen_objects[i]->flags &= ~(SEEN | ADDED | SHOWN);
135         }
136         seen_objects_nr = 0;
137 }
138
139 static uint32_t find_object_pos(const unsigned char *sha1)
140 {
141         struct object_entry *entry = packlist_find(writer.to_pack, sha1, NULL);
142
143         if (!entry) {
144                 die("Failed to write bitmap index. Packfile doesn't have full closure "
145                         "(object %s is missing)", sha1_to_hex(sha1));
146         }
147
148         return entry->in_pack_pos;
149 }
150
151 static void show_object(struct object *object, const struct name_path *path,
152                         const char *last, void *data)
153 {
154         struct bitmap *base = data;
155         bitmap_set(base, find_object_pos(object->oid.hash));
156         mark_as_seen(object);
157 }
158
159 static void show_commit(struct commit *commit, void *data)
160 {
161         mark_as_seen((struct object *)commit);
162 }
163
164 static int
165 add_to_include_set(struct bitmap *base, struct commit *commit)
166 {
167         khiter_t hash_pos;
168         uint32_t bitmap_pos = find_object_pos(commit->object.oid.hash);
169
170         if (bitmap_get(base, bitmap_pos))
171                 return 0;
172
173         hash_pos = kh_get_sha1(writer.bitmaps, commit->object.oid.hash);
174         if (hash_pos < kh_end(writer.bitmaps)) {
175                 struct bitmapped_commit *bc = kh_value(writer.bitmaps, hash_pos);
176                 bitmap_or_ewah(base, bc->bitmap);
177                 return 0;
178         }
179
180         bitmap_set(base, bitmap_pos);
181         return 1;
182 }
183
184 static int
185 should_include(struct commit *commit, void *_data)
186 {
187         struct bitmap *base = _data;
188
189         if (!add_to_include_set(base, commit)) {
190                 struct commit_list *parent = commit->parents;
191
192                 mark_as_seen((struct object *)commit);
193
194                 while (parent) {
195                         parent->item->object.flags |= SEEN;
196                         mark_as_seen((struct object *)parent->item);
197                         parent = parent->next;
198                 }
199
200                 return 0;
201         }
202
203         return 1;
204 }
205
206 static void compute_xor_offsets(void)
207 {
208         static const int MAX_XOR_OFFSET_SEARCH = 10;
209
210         int i, next = 0;
211
212         while (next < writer.selected_nr) {
213                 struct bitmapped_commit *stored = &writer.selected[next];
214
215                 int best_offset = 0;
216                 struct ewah_bitmap *best_bitmap = stored->bitmap;
217                 struct ewah_bitmap *test_xor;
218
219                 for (i = 1; i <= MAX_XOR_OFFSET_SEARCH; ++i) {
220                         int curr = next - i;
221
222                         if (curr < 0)
223                                 break;
224
225                         test_xor = ewah_pool_new();
226                         ewah_xor(writer.selected[curr].bitmap, stored->bitmap, test_xor);
227
228                         if (test_xor->buffer_size < best_bitmap->buffer_size) {
229                                 if (best_bitmap != stored->bitmap)
230                                         ewah_pool_free(best_bitmap);
231
232                                 best_bitmap = test_xor;
233                                 best_offset = i;
234                         } else {
235                                 ewah_pool_free(test_xor);
236                         }
237                 }
238
239                 stored->xor_offset = best_offset;
240                 stored->write_as = best_bitmap;
241
242                 next++;
243         }
244 }
245
246 void bitmap_writer_build(struct packing_data *to_pack)
247 {
248         static const double REUSE_BITMAP_THRESHOLD = 0.2;
249
250         int i, reuse_after, need_reset;
251         struct bitmap *base = bitmap_new();
252         struct rev_info revs;
253
254         writer.bitmaps = kh_init_sha1();
255         writer.to_pack = to_pack;
256
257         if (writer.show_progress)
258                 writer.progress = start_progress("Building bitmaps", writer.selected_nr);
259
260         init_revisions(&revs, NULL);
261         revs.tag_objects = 1;
262         revs.tree_objects = 1;
263         revs.blob_objects = 1;
264         revs.no_walk = 0;
265
266         revs.include_check = should_include;
267         reset_revision_walk();
268
269         reuse_after = writer.selected_nr * REUSE_BITMAP_THRESHOLD;
270         need_reset = 0;
271
272         for (i = writer.selected_nr - 1; i >= 0; --i) {
273                 struct bitmapped_commit *stored;
274                 struct object *object;
275
276                 khiter_t hash_pos;
277                 int hash_ret;
278
279                 stored = &writer.selected[i];
280                 object = (struct object *)stored->commit;
281
282                 if (stored->bitmap == NULL) {
283                         if (i < writer.selected_nr - 1 &&
284                             (need_reset ||
285                              !in_merge_bases(writer.selected[i + 1].commit,
286                                              stored->commit))) {
287                             bitmap_reset(base);
288                             reset_all_seen();
289                         }
290
291                         add_pending_object(&revs, object, "");
292                         revs.include_check_data = base;
293
294                         if (prepare_revision_walk(&revs))
295                                 die("revision walk setup failed");
296
297                         traverse_commit_list(&revs, show_commit, show_object, base);
298
299                         revs.pending.nr = 0;
300                         revs.pending.alloc = 0;
301                         revs.pending.objects = NULL;
302
303                         stored->bitmap = bitmap_to_ewah(base);
304                         need_reset = 0;
305                 } else
306                         need_reset = 1;
307
308                 if (i >= reuse_after)
309                         stored->flags |= BITMAP_FLAG_REUSE;
310
311                 hash_pos = kh_put_sha1(writer.bitmaps, object->oid.hash, &hash_ret);
312                 if (hash_ret == 0)
313                         die("Duplicate entry when writing index: %s",
314                             oid_to_hex(&object->oid));
315
316                 kh_value(writer.bitmaps, hash_pos) = stored;
317                 display_progress(writer.progress, writer.selected_nr - i);
318         }
319
320         bitmap_free(base);
321         stop_progress(&writer.progress);
322
323         compute_xor_offsets();
324 }
325
326 /**
327  * Select the commits that will be bitmapped
328  */
329 static inline unsigned int next_commit_index(unsigned int idx)
330 {
331         static const unsigned int MIN_COMMITS = 100;
332         static const unsigned int MAX_COMMITS = 5000;
333
334         static const unsigned int MUST_REGION = 100;
335         static const unsigned int MIN_REGION = 20000;
336
337         unsigned int offset, next;
338
339         if (idx <= MUST_REGION)
340                 return 0;
341
342         if (idx <= MIN_REGION) {
343                 offset = idx - MUST_REGION;
344                 return (offset < MIN_COMMITS) ? offset : MIN_COMMITS;
345         }
346
347         offset = idx - MIN_REGION;
348         next = (offset < MAX_COMMITS) ? offset : MAX_COMMITS;
349
350         return (next > MIN_COMMITS) ? next : MIN_COMMITS;
351 }
352
353 static int date_compare(const void *_a, const void *_b)
354 {
355         struct commit *a = *(struct commit **)_a;
356         struct commit *b = *(struct commit **)_b;
357         return (long)b->date - (long)a->date;
358 }
359
360 void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack)
361 {
362         if (prepare_bitmap_git() < 0)
363                 return;
364
365         writer.reused = kh_init_sha1();
366         rebuild_existing_bitmaps(to_pack, writer.reused, writer.show_progress);
367 }
368
369 static struct ewah_bitmap *find_reused_bitmap(const unsigned char *sha1)
370 {
371         khiter_t hash_pos;
372
373         if (!writer.reused)
374                 return NULL;
375
376         hash_pos = kh_get_sha1(writer.reused, sha1);
377         if (hash_pos >= kh_end(writer.reused))
378                 return NULL;
379
380         return kh_value(writer.reused, hash_pos);
381 }
382
383 void bitmap_writer_select_commits(struct commit **indexed_commits,
384                                   unsigned int indexed_commits_nr,
385                                   int max_bitmaps)
386 {
387         unsigned int i = 0, j, next;
388
389         qsort(indexed_commits, indexed_commits_nr, sizeof(indexed_commits[0]),
390               date_compare);
391
392         if (writer.show_progress)
393                 writer.progress = start_progress("Selecting bitmap commits", 0);
394
395         if (indexed_commits_nr < 100) {
396                 for (i = 0; i < indexed_commits_nr; ++i)
397                         push_bitmapped_commit(indexed_commits[i], NULL);
398                 return;
399         }
400
401         for (;;) {
402                 struct ewah_bitmap *reused_bitmap = NULL;
403                 struct commit *chosen = NULL;
404
405                 next = next_commit_index(i);
406
407                 if (i + next >= indexed_commits_nr)
408                         break;
409
410                 if (max_bitmaps > 0 && writer.selected_nr >= max_bitmaps) {
411                         writer.selected_nr = max_bitmaps;
412                         break;
413                 }
414
415                 if (next == 0) {
416                         chosen = indexed_commits[i];
417                         reused_bitmap = find_reused_bitmap(chosen->object.oid.hash);
418                 } else {
419                         chosen = indexed_commits[i + next];
420
421                         for (j = 0; j <= next; ++j) {
422                                 struct commit *cm = indexed_commits[i + j];
423
424                                 reused_bitmap = find_reused_bitmap(cm->object.oid.hash);
425                                 if (reused_bitmap || (cm->object.flags & NEEDS_BITMAP) != 0) {
426                                         chosen = cm;
427                                         break;
428                                 }
429
430                                 if (cm->parents && cm->parents->next)
431                                         chosen = cm;
432                         }
433                 }
434
435                 push_bitmapped_commit(chosen, reused_bitmap);
436
437                 i += next + 1;
438                 display_progress(writer.progress, i);
439         }
440
441         stop_progress(&writer.progress);
442 }
443
444
445 static int sha1write_ewah_helper(void *f, const void *buf, size_t len)
446 {
447         /* sha1write will die on error */
448         sha1write(f, buf, len);
449         return len;
450 }
451
452 /**
453  * Write the bitmap index to disk
454  */
455 static inline void dump_bitmap(struct sha1file *f, struct ewah_bitmap *bitmap)
456 {
457         if (ewah_serialize_to(bitmap, sha1write_ewah_helper, f) < 0)
458                 die("Failed to write bitmap index");
459 }
460
461 static const unsigned char *sha1_access(size_t pos, void *table)
462 {
463         struct pack_idx_entry **index = table;
464         return index[pos]->sha1;
465 }
466
467 static void write_selected_commits_v1(struct sha1file *f,
468                                       struct pack_idx_entry **index,
469                                       uint32_t index_nr)
470 {
471         int i;
472
473         for (i = 0; i < writer.selected_nr; ++i) {
474                 struct bitmapped_commit *stored = &writer.selected[i];
475
476                 int commit_pos =
477                         sha1_pos(stored->commit->object.oid.hash, index, index_nr, sha1_access);
478
479                 if (commit_pos < 0)
480                         die("BUG: trying to write commit not in index");
481
482                 sha1write_be32(f, commit_pos);
483                 sha1write_u8(f, stored->xor_offset);
484                 sha1write_u8(f, stored->flags);
485
486                 dump_bitmap(f, stored->write_as);
487         }
488 }
489
490 static void write_hash_cache(struct sha1file *f,
491                              struct pack_idx_entry **index,
492                              uint32_t index_nr)
493 {
494         uint32_t i;
495
496         for (i = 0; i < index_nr; ++i) {
497                 struct object_entry *entry = (struct object_entry *)index[i];
498                 uint32_t hash_value = htonl(entry->hash);
499                 sha1write(f, &hash_value, sizeof(hash_value));
500         }
501 }
502
503 void bitmap_writer_set_checksum(unsigned char *sha1)
504 {
505         hashcpy(writer.pack_checksum, sha1);
506 }
507
508 void bitmap_writer_finish(struct pack_idx_entry **index,
509                           uint32_t index_nr,
510                           const char *filename,
511                           uint16_t options)
512 {
513         static char tmp_file[PATH_MAX];
514         static uint16_t default_version = 1;
515         static uint16_t flags = BITMAP_OPT_FULL_DAG;
516         struct sha1file *f;
517
518         struct bitmap_disk_header header;
519
520         int fd = odb_mkstemp(tmp_file, sizeof(tmp_file), "pack/tmp_bitmap_XXXXXX");
521
522         if (fd < 0)
523                 die_errno("unable to create '%s'", tmp_file);
524         f = sha1fd(fd, tmp_file);
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         sha1write(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         sha1close(f, NULL, CSUM_FSYNC);
543
544         if (adjust_shared_perm(tmp_file))
545                 die_errno("unable to make temporary bitmap file readable");
546
547         if (rename(tmp_file, filename))
548                 die_errno("unable to rename temporary bitmap file to '%s'", filename);
549 }