stash: remove now superfluos help for "stash push"
[git.git] / pack-bitmap-write.c
bloba8df5ce2ab67bfdb5445e4c02e4ad65032abe9a0
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"
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;
23 struct bitmap_writer {
24         struct ewah_bitmap *commits;
25         struct ewah_bitmap *trees;
26         struct ewah_bitmap *blobs;
27         struct ewah_bitmap *tags;
29         khash_sha1 *bitmaps;
30         khash_sha1 *reused;
31         struct packing_data *to_pack;
33         struct bitmapped_commit *selected;
34         unsigned int selected_nr, selected_alloc;
36         struct progress *progress;
37         int show_progress;
38         unsigned char pack_checksum[20];
41 static struct bitmap_writer writer;
43 void bitmap_writer_show_progress(int show)
45         writer.show_progress = show;
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)
54         uint32_t i;
56         writer.commits = ewah_new();
57         writer.trees = ewah_new();
58         writer.blobs = ewah_new();
59         writer.tags = ewah_new();
61         for (i = 0; i < index_nr; ++i) {
62                 struct object_entry *entry = (struct object_entry *)index[i];
63                 enum object_type real_type;
65                 entry->in_pack_pos = i;
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;
75                 default:
76                         real_type = sha1_object_info(entry->idx.oid.hash,
77                                                      NULL);
78                         break;
79                 }
81                 switch (real_type) {
82                 case OBJ_COMMIT:
83                         ewah_set(writer.commits, i);
84                         break;
86                 case OBJ_TREE:
87                         ewah_set(writer.trees, i);
88                         break;
90                 case OBJ_BLOB:
91                         ewah_set(writer.blobs, i);
92                         break;
94                 case OBJ_TAG:
95                         ewah_set(writer.tags, i);
96                         break;
98                 default:
99                         die("Missing type information for %s (%d/%d)",
100                             oid_to_hex(&entry->idx.oid), real_type,
101                             entry->type);
102                 }
103         }
107  * Compute the actual bitmaps
108  */
109 static struct object **seen_objects;
110 static unsigned int seen_objects_nr, seen_objects_alloc;
112 static inline void push_bitmapped_commit(struct commit *commit, struct ewah_bitmap *reused)
114         if (writer.selected_nr >= writer.selected_alloc) {
115                 writer.selected_alloc = (writer.selected_alloc + 32) * 2;
116                 REALLOC_ARRAY(writer.selected, writer.selected_alloc);
117         }
119         writer.selected[writer.selected_nr].commit = commit;
120         writer.selected[writer.selected_nr].bitmap = reused;
121         writer.selected[writer.selected_nr].flags = 0;
123         writer.selected_nr++;
126 static inline void mark_as_seen(struct object *object)
128         ALLOC_GROW(seen_objects, seen_objects_nr + 1, seen_objects_alloc);
129         seen_objects[seen_objects_nr++] = object;
132 static inline void reset_all_seen(void)
134         unsigned int i;
135         for (i = 0; i < seen_objects_nr; ++i) {
136                 seen_objects[i]->flags &= ~(SEEN | ADDED | SHOWN);
137         }
138         seen_objects_nr = 0;
141 static uint32_t find_object_pos(const unsigned char *sha1)
143         struct object_entry *entry = packlist_find(writer.to_pack, sha1, NULL);
145         if (!entry) {
146                 die("Failed to write bitmap index. Packfile doesn't have full closure "
147                         "(object %s is missing)", sha1_to_hex(sha1));
148         }
150         return entry->in_pack_pos;
153 static void show_object(struct object *object, const char *name, void *data)
155         struct bitmap *base = data;
156         bitmap_set(base, find_object_pos(object->oid.hash));
157         mark_as_seen(object);
160 static void show_commit(struct commit *commit, void *data)
162         mark_as_seen((struct object *)commit);
165 static int
166 add_to_include_set(struct bitmap *base, struct commit *commit)
168         khiter_t hash_pos;
169         uint32_t bitmap_pos = find_object_pos(commit->object.oid.hash);
171         if (bitmap_get(base, bitmap_pos))
172                 return 0;
174         hash_pos = kh_get_sha1(writer.bitmaps, commit->object.oid.hash);
175         if (hash_pos < kh_end(writer.bitmaps)) {
176                 struct bitmapped_commit *bc = kh_value(writer.bitmaps, hash_pos);
177                 bitmap_or_ewah(base, bc->bitmap);
178                 return 0;
179         }
181         bitmap_set(base, bitmap_pos);
182         return 1;
185 static int
186 should_include(struct commit *commit, void *_data)
188         struct bitmap *base = _data;
190         if (!add_to_include_set(base, commit)) {
191                 struct commit_list *parent = commit->parents;
193                 mark_as_seen((struct object *)commit);
195                 while (parent) {
196                         parent->item->object.flags |= SEEN;
197                         mark_as_seen((struct object *)parent->item);
198                         parent = parent->next;
199                 }
201                 return 0;
202         }
204         return 1;
207 static void compute_xor_offsets(void)
209         static const int MAX_XOR_OFFSET_SEARCH = 10;
211         int i, next = 0;
213         while (next < writer.selected_nr) {
214                 struct bitmapped_commit *stored = &writer.selected[next];
216                 int best_offset = 0;
217                 struct ewah_bitmap *best_bitmap = stored->bitmap;
218                 struct ewah_bitmap *test_xor;
220                 for (i = 1; i <= MAX_XOR_OFFSET_SEARCH; ++i) {
221                         int curr = next - i;
223                         if (curr < 0)
224                                 break;
226                         test_xor = ewah_pool_new();
227                         ewah_xor(writer.selected[curr].bitmap, stored->bitmap, test_xor);
229                         if (test_xor->buffer_size < best_bitmap->buffer_size) {
230                                 if (best_bitmap != stored->bitmap)
231                                         ewah_pool_free(best_bitmap);
233                                 best_bitmap = test_xor;
234                                 best_offset = i;
235                         } else {
236                                 ewah_pool_free(test_xor);
237                         }
238                 }
240                 stored->xor_offset = best_offset;
241                 stored->write_as = best_bitmap;
243                 next++;
244         }
247 void bitmap_writer_build(struct packing_data *to_pack)
249         static const double REUSE_BITMAP_THRESHOLD = 0.2;
251         int i, reuse_after, need_reset;
252         struct bitmap *base = bitmap_new();
253         struct rev_info revs;
255         writer.bitmaps = kh_init_sha1();
256         writer.to_pack = to_pack;
258         if (writer.show_progress)
259                 writer.progress = start_progress("Building bitmaps", writer.selected_nr);
261         init_revisions(&revs, NULL);
262         revs.tag_objects = 1;
263         revs.tree_objects = 1;
264         revs.blob_objects = 1;
265         revs.no_walk = 0;
267         revs.include_check = should_include;
268         reset_revision_walk();
270         reuse_after = writer.selected_nr * REUSE_BITMAP_THRESHOLD;
271         need_reset = 0;
273         for (i = writer.selected_nr - 1; i >= 0; --i) {
274                 struct bitmapped_commit *stored;
275                 struct object *object;
277                 khiter_t hash_pos;
278                 int hash_ret;
280                 stored = &writer.selected[i];
281                 object = (struct object *)stored->commit;
283                 if (stored->bitmap == NULL) {
284                         if (i < writer.selected_nr - 1 &&
285                             (need_reset ||
286                              !in_merge_bases(writer.selected[i + 1].commit,
287                                              stored->commit))) {
288                             bitmap_reset(base);
289                             reset_all_seen();
290                         }
292                         add_pending_object(&revs, object, "");
293                         revs.include_check_data = base;
295                         if (prepare_revision_walk(&revs))
296                                 die("revision walk setup failed");
298                         traverse_commit_list(&revs, show_commit, show_object, base);
300                         object_array_clear(&revs.pending);
302                         stored->bitmap = bitmap_to_ewah(base);
303                         need_reset = 0;
304                 } else
305                         need_reset = 1;
307                 if (i >= reuse_after)
308                         stored->flags |= BITMAP_FLAG_REUSE;
310                 hash_pos = kh_put_sha1(writer.bitmaps, object->oid.hash, &hash_ret);
311                 if (hash_ret == 0)
312                         die("Duplicate entry when writing index: %s",
313                             oid_to_hex(&object->oid));
315                 kh_value(writer.bitmaps, hash_pos) = stored;
316                 display_progress(writer.progress, writer.selected_nr - i);
317         }
319         bitmap_free(base);
320         stop_progress(&writer.progress);
322         compute_xor_offsets();
326  * Select the commits that will be bitmapped
327  */
328 static inline unsigned int next_commit_index(unsigned int idx)
330         static const unsigned int MIN_COMMITS = 100;
331         static const unsigned int MAX_COMMITS = 5000;
333         static const unsigned int MUST_REGION = 100;
334         static const unsigned int MIN_REGION = 20000;
336         unsigned int offset, next;
338         if (idx <= MUST_REGION)
339                 return 0;
341         if (idx <= MIN_REGION) {
342                 offset = idx - MUST_REGION;
343                 return (offset < MIN_COMMITS) ? offset : MIN_COMMITS;
344         }
346         offset = idx - MIN_REGION;
347         next = (offset < MAX_COMMITS) ? offset : MAX_COMMITS;
349         return (next > MIN_COMMITS) ? next : MIN_COMMITS;
352 static int date_compare(const void *_a, const void *_b)
354         struct commit *a = *(struct commit **)_a;
355         struct commit *b = *(struct commit **)_b;
356         return (long)b->date - (long)a->date;
359 void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack)
361         if (prepare_bitmap_git() < 0)
362                 return;
364         writer.reused = kh_init_sha1();
365         rebuild_existing_bitmaps(to_pack, writer.reused, writer.show_progress);
368 static struct ewah_bitmap *find_reused_bitmap(const unsigned char *sha1)
370         khiter_t hash_pos;
372         if (!writer.reused)
373                 return NULL;
375         hash_pos = kh_get_sha1(writer.reused, sha1);
376         if (hash_pos >= kh_end(writer.reused))
377                 return NULL;
379         return kh_value(writer.reused, hash_pos);
382 void bitmap_writer_select_commits(struct commit **indexed_commits,
383                                   unsigned int indexed_commits_nr,
384                                   int max_bitmaps)
386         unsigned int i = 0, j, next;
388         QSORT(indexed_commits, indexed_commits_nr, date_compare);
390         if (writer.show_progress)
391                 writer.progress = start_progress("Selecting bitmap commits", 0);
393         if (indexed_commits_nr < 100) {
394                 for (i = 0; i < indexed_commits_nr; ++i)
395                         push_bitmapped_commit(indexed_commits[i], NULL);
396                 return;
397         }
399         for (;;) {
400                 struct ewah_bitmap *reused_bitmap = NULL;
401                 struct commit *chosen = NULL;
403                 next = next_commit_index(i);
405                 if (i + next >= indexed_commits_nr)
406                         break;
408                 if (max_bitmaps > 0 && writer.selected_nr >= max_bitmaps) {
409                         writer.selected_nr = max_bitmaps;
410                         break;
411                 }
413                 if (next == 0) {
414                         chosen = indexed_commits[i];
415                         reused_bitmap = find_reused_bitmap(chosen->object.oid.hash);
416                 } else {
417                         chosen = indexed_commits[i + next];
419                         for (j = 0; j <= next; ++j) {
420                                 struct commit *cm = indexed_commits[i + j];
422                                 reused_bitmap = find_reused_bitmap(cm->object.oid.hash);
423                                 if (reused_bitmap || (cm->object.flags & NEEDS_BITMAP) != 0) {
424                                         chosen = cm;
425                                         break;
426                                 }
428                                 if (cm->parents && cm->parents->next)
429                                         chosen = cm;
430                         }
431                 }
433                 push_bitmapped_commit(chosen, reused_bitmap);
435                 i += next + 1;
436                 display_progress(writer.progress, i);
437         }
439         stop_progress(&writer.progress);
443 static int sha1write_ewah_helper(void *f, const void *buf, size_t len)
445         /* sha1write will die on error */
446         sha1write(f, buf, len);
447         return len;
451  * Write the bitmap index to disk
452  */
453 static inline void dump_bitmap(struct sha1file *f, struct ewah_bitmap *bitmap)
455         if (ewah_serialize_to(bitmap, sha1write_ewah_helper, f) < 0)
456                 die("Failed to write bitmap index");
459 static const unsigned char *sha1_access(size_t pos, void *table)
461         struct pack_idx_entry **index = table;
462         return index[pos]->oid.hash;
465 static void write_selected_commits_v1(struct sha1file *f,
466                                       struct pack_idx_entry **index,
467                                       uint32_t index_nr)
469         int i;
471         for (i = 0; i < writer.selected_nr; ++i) {
472                 struct bitmapped_commit *stored = &writer.selected[i];
474                 int commit_pos =
475                         sha1_pos(stored->commit->object.oid.hash, index, index_nr, sha1_access);
477                 if (commit_pos < 0)
478                         die("BUG: trying to write commit not in index");
480                 sha1write_be32(f, commit_pos);
481                 sha1write_u8(f, stored->xor_offset);
482                 sha1write_u8(f, stored->flags);
484                 dump_bitmap(f, stored->write_as);
485         }
488 static void write_hash_cache(struct sha1file *f,
489                              struct pack_idx_entry **index,
490                              uint32_t index_nr)
492         uint32_t i;
494         for (i = 0; i < index_nr; ++i) {
495                 struct object_entry *entry = (struct object_entry *)index[i];
496                 uint32_t hash_value = htonl(entry->hash);
497                 sha1write(f, &hash_value, sizeof(hash_value));
498         }
501 void bitmap_writer_set_checksum(unsigned char *sha1)
503         hashcpy(writer.pack_checksum, sha1);
506 void bitmap_writer_finish(struct pack_idx_entry **index,
507                           uint32_t index_nr,
508                           const char *filename,
509                           uint16_t options)
511         static uint16_t default_version = 1;
512         static uint16_t flags = BITMAP_OPT_FULL_DAG;
513         struct strbuf tmp_file = STRBUF_INIT;
514         struct sha1file *f;
516         struct bitmap_disk_header header;
518         int fd = odb_mkstemp(&tmp_file, "pack/tmp_bitmap_XXXXXX");
520         f = sha1fd(fd, tmp_file.buf);
522         memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
523         header.version = htons(default_version);
524         header.options = htons(flags | options);
525         header.entry_count = htonl(writer.selected_nr);
526         hashcpy(header.checksum, writer.pack_checksum);
528         sha1write(f, &header, sizeof(header));
529         dump_bitmap(f, writer.commits);
530         dump_bitmap(f, writer.trees);
531         dump_bitmap(f, writer.blobs);
532         dump_bitmap(f, writer.tags);
533         write_selected_commits_v1(f, index, index_nr);
535         if (options & BITMAP_OPT_HASH_CACHE)
536                 write_hash_cache(f, index, index_nr);
538         sha1close(f, NULL, CSUM_FSYNC);
540         if (adjust_shared_perm(tmp_file.buf))
541                 die_errno("unable to make temporary bitmap file readable");
543         if (rename(tmp_file.buf, filename))
544                 die_errno("unable to rename temporary bitmap file to '%s'", filename);
546         strbuf_release(&tmp_file);