Merge branch 'jt/lazy-object-fetch-fix'
[git] / delta-islands.c
1 #include "cache.h"
2 #include "attr.h"
3 #include "object.h"
4 #include "blob.h"
5 #include "commit.h"
6 #include "tag.h"
7 #include "tree.h"
8 #include "delta.h"
9 #include "pack.h"
10 #include "tree-walk.h"
11 #include "diff.h"
12 #include "revision.h"
13 #include "list-objects.h"
14 #include "progress.h"
15 #include "refs.h"
16 #include "khash.h"
17 #include "pack-bitmap.h"
18 #include "pack-objects.h"
19 #include "delta-islands.h"
20 #include "sha1-array.h"
21 #include "config.h"
22
23 KHASH_INIT(str, const char *, void *, 1, kh_str_hash_func, kh_str_hash_equal)
24
25 static khash_sha1 *island_marks;
26 static unsigned island_counter;
27 static unsigned island_counter_core;
28
29 static kh_str_t *remote_islands;
30
31 struct remote_island {
32         uint64_t hash;
33         struct oid_array oids;
34 };
35
36 struct island_bitmap {
37         uint32_t refcount;
38         uint32_t bits[FLEX_ARRAY];
39 };
40
41 static uint32_t island_bitmap_size;
42
43 /*
44  * Allocate a new bitmap; if "old" is not NULL, the new bitmap will be a copy
45  * of "old". Otherwise, the new bitmap is empty.
46  */
47 static struct island_bitmap *island_bitmap_new(const struct island_bitmap *old)
48 {
49         size_t size = sizeof(struct island_bitmap) + (island_bitmap_size * 4);
50         struct island_bitmap *b = xcalloc(1, size);
51
52         if (old)
53                 memcpy(b, old, size);
54
55         b->refcount = 1;
56         return b;
57 }
58
59 static void island_bitmap_or(struct island_bitmap *a, const struct island_bitmap *b)
60 {
61         uint32_t i;
62
63         for (i = 0; i < island_bitmap_size; ++i)
64                 a->bits[i] |= b->bits[i];
65 }
66
67 static int island_bitmap_is_subset(struct island_bitmap *self,
68                 struct island_bitmap *super)
69 {
70         uint32_t i;
71
72         if (self == super)
73                 return 1;
74
75         for (i = 0; i < island_bitmap_size; ++i) {
76                 if ((self->bits[i] & super->bits[i]) != self->bits[i])
77                         return 0;
78         }
79
80         return 1;
81 }
82
83 #define ISLAND_BITMAP_BLOCK(x) (x / 32)
84 #define ISLAND_BITMAP_MASK(x) (1 << (x % 32))
85
86 static void island_bitmap_set(struct island_bitmap *self, uint32_t i)
87 {
88         self->bits[ISLAND_BITMAP_BLOCK(i)] |= ISLAND_BITMAP_MASK(i);
89 }
90
91 static int island_bitmap_get(struct island_bitmap *self, uint32_t i)
92 {
93         return (self->bits[ISLAND_BITMAP_BLOCK(i)] & ISLAND_BITMAP_MASK(i)) != 0;
94 }
95
96 int in_same_island(const struct object_id *trg_oid, const struct object_id *src_oid)
97 {
98         khiter_t trg_pos, src_pos;
99
100         /* If we aren't using islands, assume everything goes together. */
101         if (!island_marks)
102                 return 1;
103
104         /*
105          * If we don't have a bitmap for the target, we can delta it
106          * against anything -- it's not an important object
107          */
108         trg_pos = kh_get_sha1(island_marks, trg_oid->hash);
109         if (trg_pos >= kh_end(island_marks))
110                 return 1;
111
112         /*
113          * if the source (our delta base) doesn't have a bitmap,
114          * we don't want to base any deltas on it!
115          */
116         src_pos = kh_get_sha1(island_marks, src_oid->hash);
117         if (src_pos >= kh_end(island_marks))
118                 return 0;
119
120         return island_bitmap_is_subset(kh_value(island_marks, trg_pos),
121                                 kh_value(island_marks, src_pos));
122 }
123
124 int island_delta_cmp(const struct object_id *a, const struct object_id *b)
125 {
126         khiter_t a_pos, b_pos;
127         struct island_bitmap *a_bitmap = NULL, *b_bitmap = NULL;
128
129         if (!island_marks)
130                 return 0;
131
132         a_pos = kh_get_sha1(island_marks, a->hash);
133         if (a_pos < kh_end(island_marks))
134                 a_bitmap = kh_value(island_marks, a_pos);
135
136         b_pos = kh_get_sha1(island_marks, b->hash);
137         if (b_pos < kh_end(island_marks))
138                 b_bitmap = kh_value(island_marks, b_pos);
139
140         if (a_bitmap) {
141                 if (!b_bitmap || !island_bitmap_is_subset(a_bitmap, b_bitmap))
142                         return -1;
143         }
144         if (b_bitmap) {
145                 if (!a_bitmap || !island_bitmap_is_subset(b_bitmap, a_bitmap))
146                         return 1;
147         }
148
149         return 0;
150 }
151
152 static struct island_bitmap *create_or_get_island_marks(struct object *obj)
153 {
154         khiter_t pos;
155         int hash_ret;
156
157         pos = kh_put_sha1(island_marks, obj->oid.hash, &hash_ret);
158         if (hash_ret)
159                 kh_value(island_marks, pos) = island_bitmap_new(NULL);
160
161         return kh_value(island_marks, pos);
162 }
163
164 static void set_island_marks(struct object *obj, struct island_bitmap *marks)
165 {
166         struct island_bitmap *b;
167         khiter_t pos;
168         int hash_ret;
169
170         pos = kh_put_sha1(island_marks, obj->oid.hash, &hash_ret);
171         if (hash_ret) {
172                 /*
173                  * We don't have one yet; make a copy-on-write of the
174                  * parent.
175                  */
176                 marks->refcount++;
177                 kh_value(island_marks, pos) = marks;
178                 return;
179         }
180
181         /*
182          * We do have it. Make sure we split any copy-on-write before
183          * updating.
184          */
185         b = kh_value(island_marks, pos);
186         if (b->refcount > 1) {
187                 b->refcount--;
188                 b = kh_value(island_marks, pos) = island_bitmap_new(b);
189         }
190         island_bitmap_or(b, marks);
191 }
192
193 static void mark_remote_island_1(struct remote_island *rl, int is_core_island)
194 {
195         uint32_t i;
196
197         for (i = 0; i < rl->oids.nr; ++i) {
198                 struct island_bitmap *marks;
199                 struct object *obj = parse_object(the_repository, &rl->oids.oid[i]);
200
201                 if (!obj)
202                         continue;
203
204                 marks = create_or_get_island_marks(obj);
205                 island_bitmap_set(marks, island_counter);
206
207                 if (is_core_island && obj->type == OBJ_COMMIT)
208                         obj->flags |= NEEDS_BITMAP;
209
210                 /* If it was a tag, also make sure we hit the underlying object. */
211                 while (obj && obj->type == OBJ_TAG) {
212                         obj = ((struct tag *)obj)->tagged;
213                         if (obj) {
214                                 parse_object(the_repository, &obj->oid);
215                                 marks = create_or_get_island_marks(obj);
216                                 island_bitmap_set(marks, island_counter);
217                         }
218                 }
219         }
220
221         if (is_core_island)
222                 island_counter_core = island_counter;
223
224         island_counter++;
225 }
226
227 struct tree_islands_todo {
228         struct object_entry *entry;
229         unsigned int depth;
230 };
231
232 static int tree_depth_compare(const void *a, const void *b)
233 {
234         const struct tree_islands_todo *todo_a = a;
235         const struct tree_islands_todo *todo_b = b;
236
237         return todo_a->depth - todo_b->depth;
238 }
239
240 void resolve_tree_islands(int progress, struct packing_data *to_pack)
241 {
242         struct progress *progress_state = NULL;
243         struct tree_islands_todo *todo;
244         int nr = 0;
245         int i;
246
247         if (!island_marks)
248                 return;
249
250         /*
251          * We process only trees, as commits and tags have already been handled
252          * (and passed their marks on to root trees, as well. We must make sure
253          * to process them in descending tree-depth order so that marks
254          * propagate down the tree properly, even if a sub-tree is found in
255          * multiple parent trees.
256          */
257         ALLOC_ARRAY(todo, to_pack->nr_objects);
258         for (i = 0; i < to_pack->nr_objects; i++) {
259                 if (oe_type(&to_pack->objects[i]) == OBJ_TREE) {
260                         todo[nr].entry = &to_pack->objects[i];
261                         todo[nr].depth = oe_tree_depth(to_pack, &to_pack->objects[i]);
262                         nr++;
263                 }
264         }
265         QSORT(todo, nr, tree_depth_compare);
266
267         if (progress)
268                 progress_state = start_progress(_("Propagating island marks"), nr);
269
270         for (i = 0; i < nr; i++) {
271                 struct object_entry *ent = todo[i].entry;
272                 struct island_bitmap *root_marks;
273                 struct tree *tree;
274                 struct tree_desc desc;
275                 struct name_entry entry;
276                 khiter_t pos;
277
278                 pos = kh_get_sha1(island_marks, ent->idx.oid.hash);
279                 if (pos >= kh_end(island_marks))
280                         continue;
281
282                 root_marks = kh_value(island_marks, pos);
283
284                 tree = lookup_tree(the_repository, &ent->idx.oid);
285                 if (!tree || parse_tree(tree) < 0)
286                         die(_("bad tree object %s"), oid_to_hex(&ent->idx.oid));
287
288                 init_tree_desc(&desc, tree->buffer, tree->size);
289                 while (tree_entry(&desc, &entry)) {
290                         struct object *obj;
291
292                         if (S_ISGITLINK(entry.mode))
293                                 continue;
294
295                         obj = lookup_object(the_repository, entry.oid->hash);
296                         if (!obj)
297                                 continue;
298
299                         set_island_marks(obj, root_marks);
300                 }
301
302                 free_tree_buffer(tree);
303
304                 display_progress(progress_state, i+1);
305         }
306
307         stop_progress(&progress_state);
308         free(todo);
309 }
310
311 static regex_t *island_regexes;
312 static unsigned int island_regexes_alloc, island_regexes_nr;
313 static const char *core_island_name;
314
315 static int island_config_callback(const char *k, const char *v, void *cb)
316 {
317         if (!strcmp(k, "pack.island")) {
318                 struct strbuf re = STRBUF_INIT;
319
320                 if (!v)
321                         return config_error_nonbool(k);
322
323                 ALLOC_GROW(island_regexes, island_regexes_nr + 1, island_regexes_alloc);
324
325                 if (*v != '^')
326                         strbuf_addch(&re, '^');
327                 strbuf_addstr(&re, v);
328
329                 if (regcomp(&island_regexes[island_regexes_nr], re.buf, REG_EXTENDED))
330                         die(_("failed to load island regex for '%s': %s"), k, re.buf);
331
332                 strbuf_release(&re);
333                 island_regexes_nr++;
334                 return 0;
335         }
336
337         if (!strcmp(k, "pack.islandcore"))
338                 return git_config_string(&core_island_name, k, v);
339
340         return 0;
341 }
342
343 static void add_ref_to_island(const char *island_name, const struct object_id *oid)
344 {
345         uint64_t sha_core;
346         struct remote_island *rl = NULL;
347
348         int hash_ret;
349         khiter_t pos = kh_put_str(remote_islands, island_name, &hash_ret);
350
351         if (hash_ret) {
352                 kh_key(remote_islands, pos) = xstrdup(island_name);
353                 kh_value(remote_islands, pos) = xcalloc(1, sizeof(struct remote_island));
354         }
355
356         rl = kh_value(remote_islands, pos);
357         oid_array_append(&rl->oids, oid);
358
359         memcpy(&sha_core, oid->hash, sizeof(uint64_t));
360         rl->hash += sha_core;
361 }
362
363 static int find_island_for_ref(const char *refname, const struct object_id *oid,
364                                int flags, void *data)
365 {
366         /*
367          * We should advertise 'ARRAY_SIZE(matches) - 2' as the max,
368          * so we can diagnose below a config with more capture groups
369          * than we support.
370          */
371         regmatch_t matches[16];
372         int i, m;
373         struct strbuf island_name = STRBUF_INIT;
374
375         /* walk backwards to get last-one-wins ordering */
376         for (i = island_regexes_nr - 1; i >= 0; i--) {
377                 if (!regexec(&island_regexes[i], refname,
378                              ARRAY_SIZE(matches), matches, 0))
379                         break;
380         }
381
382         if (i < 0)
383                 return 0;
384
385         if (matches[ARRAY_SIZE(matches) - 1].rm_so != -1)
386                 warning(_("island regex from config has "
387                           "too many capture groups (max=%d)"),
388                         (int)ARRAY_SIZE(matches) - 2);
389
390         for (m = 1; m < ARRAY_SIZE(matches); m++) {
391                 regmatch_t *match = &matches[m];
392
393                 if (match->rm_so == -1)
394                         continue;
395
396                 if (island_name.len)
397                         strbuf_addch(&island_name, '-');
398
399                 strbuf_add(&island_name, refname + match->rm_so, match->rm_eo - match->rm_so);
400         }
401
402         add_ref_to_island(island_name.buf, oid);
403         strbuf_release(&island_name);
404         return 0;
405 }
406
407 static struct remote_island *get_core_island(void)
408 {
409         if (core_island_name) {
410                 khiter_t pos = kh_get_str(remote_islands, core_island_name);
411                 if (pos < kh_end(remote_islands))
412                         return kh_value(remote_islands, pos);
413         }
414
415         return NULL;
416 }
417
418 static void deduplicate_islands(void)
419 {
420         struct remote_island *island, *core = NULL, **list;
421         unsigned int island_count, dst, src, ref, i = 0;
422
423         island_count = kh_size(remote_islands);
424         ALLOC_ARRAY(list, island_count);
425
426         kh_foreach_value(remote_islands, island, {
427                 list[i++] = island;
428         });
429
430         for (ref = 0; ref + 1 < island_count; ref++) {
431                 for (src = ref + 1, dst = src; src < island_count; src++) {
432                         if (list[ref]->hash == list[src]->hash)
433                                 continue;
434
435                         if (src != dst)
436                                 list[dst] = list[src];
437
438                         dst++;
439                 }
440                 island_count = dst;
441         }
442
443         island_bitmap_size = (island_count / 32) + 1;
444         core = get_core_island();
445
446         for (i = 0; i < island_count; ++i) {
447                 mark_remote_island_1(list[i], core && list[i]->hash == core->hash);
448         }
449
450         free(list);
451 }
452
453 void load_delta_islands(void)
454 {
455         island_marks = kh_init_sha1();
456         remote_islands = kh_init_str();
457
458         git_config(island_config_callback, NULL);
459         for_each_ref(find_island_for_ref, NULL);
460         deduplicate_islands();
461
462         fprintf(stderr, _("Marked %d islands, done.\n"), island_counter);
463 }
464
465 void propagate_island_marks(struct commit *commit)
466 {
467         khiter_t pos = kh_get_sha1(island_marks, commit->object.oid.hash);
468
469         if (pos < kh_end(island_marks)) {
470                 struct commit_list *p;
471                 struct island_bitmap *root_marks = kh_value(island_marks, pos);
472
473                 parse_commit(commit);
474                 set_island_marks(&get_commit_tree(commit)->object, root_marks);
475                 for (p = commit->parents; p; p = p->next)
476                         set_island_marks(&p->item->object, root_marks);
477         }
478 }
479
480 int compute_pack_layers(struct packing_data *to_pack)
481 {
482         uint32_t i;
483
484         if (!core_island_name || !island_marks)
485                 return 1;
486
487         for (i = 0; i < to_pack->nr_objects; ++i) {
488                 struct object_entry *entry = &to_pack->objects[i];
489                 khiter_t pos = kh_get_sha1(island_marks, entry->idx.oid.hash);
490
491                 oe_set_layer(to_pack, entry, 1);
492
493                 if (pos < kh_end(island_marks)) {
494                         struct island_bitmap *bitmap = kh_value(island_marks, pos);
495
496                         if (island_bitmap_get(bitmap, island_counter_core))
497                                 oe_set_layer(to_pack, entry, 0);
498                 }
499         }
500
501         return 2;
502 }