summaryrefslogtreecommitdiff
path: root/delta-islands.c
blob: 09dbd3cf72ba99d0f8ab793298b6b80215d450d3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
#include "cache.h"
#include "attr.h"
#include "object.h"
#include "blob.h"
#include "commit.h"
#include "tag.h"
#include "tree.h"
#include "delta.h"
#include "pack.h"
#include "tree-walk.h"
#include "diff.h"
#include "revision.h"
#include "list-objects.h"
#include "progress.h"
#include "refs.h"
#include "khash.h"
#include "pack-bitmap.h"
#include "pack-objects.h"
#include "delta-islands.h"
#include "sha1-array.h"
#include "config.h"
 
KHASH_INIT(str, const char *, void *, 1, kh_str_hash_func, kh_str_hash_equal)
 
static kh_oid_map_t *island_marks;
static unsigned island_counter;
static unsigned island_counter_core;
 
static kh_str_t *remote_islands;
 
struct remote_island {
	uint64_t hash;
	struct oid_array oids;
};
 
struct island_bitmap {
	uint32_t refcount;
	uint32_t bits[FLEX_ARRAY];
};
 
static uint32_t island_bitmap_size;
 
/*
 * Allocate a new bitmap; if "old" is not NULL, the new bitmap will be a copy
 * of "old". Otherwise, the new bitmap is empty.
 */
static struct island_bitmap *island_bitmap_new(const struct island_bitmap *old)
{
	size_t size = sizeof(struct island_bitmap) + (island_bitmap_size * 4);
	struct island_bitmap *b = xcalloc(1, size);
 
	if (old)
		memcpy(b, old, size);
 
	b->refcount = 1;
	return b;
}
 
static void island_bitmap_or(struct island_bitmap *a, const struct island_bitmap *b)
{
	uint32_t i;
 
	for (i = 0; i < island_bitmap_size; ++i)
		a->bits[i] |= b->bits[i];
}
 
static int island_bitmap_is_subset(struct island_bitmap *self,
		struct island_bitmap *super)
{
	uint32_t i;
 
	if (self == super)
		return 1;
 
	for (i = 0; i < island_bitmap_size; ++i) {
		if ((self->bits[i] & super->bits[i]) != self->bits[i])
			return 0;
	}
 
	return 1;
}
 
#define ISLAND_BITMAP_BLOCK(x) (x / 32)
#define ISLAND_BITMAP_MASK(x) (1 << (x % 32))
 
static void island_bitmap_set(struct island_bitmap *self, uint32_t i)
{
	self->bits[ISLAND_BITMAP_BLOCK(i)] |= ISLAND_BITMAP_MASK(i);
}
 
static int island_bitmap_get(struct island_bitmap *self, uint32_t i)
{
	return (self->bits[ISLAND_BITMAP_BLOCK(i)] & ISLAND_BITMAP_MASK(i)) != 0;
}
 
int in_same_island(const struct object_id *trg_oid, const struct object_id *src_oid)
{
	khiter_t trg_pos, src_pos;
 
	/* If we aren't using islands, assume everything goes together. */
	if (!island_marks)
		return 1;
 
	/*
	 * If we don't have a bitmap for the target, we can delta it
	 * against anything -- it's not an important object
	 */
	trg_pos = kh_get_oid_map(island_marks, *trg_oid);
	if (trg_pos >= kh_end(island_marks))
		return 1;
 
	/*
	 * if the source (our delta base) doesn't have a bitmap,
	 * we don't want to base any deltas on it!
	 */
	src_pos = kh_get_oid_map(island_marks, *src_oid);
	if (src_pos >= kh_end(island_marks))
		return 0;
 
	return island_bitmap_is_subset(kh_value(island_marks, trg_pos),
				kh_value(island_marks, src_pos));
}
 
int island_delta_cmp(const struct object_id *a, const struct object_id *b)
{
	khiter_t a_pos, b_pos;
	struct island_bitmap *a_bitmap = NULL, *b_bitmap = NULL;
 
	if (!island_marks)
		return 0;
 
	a_pos = kh_get_oid_map(island_marks, *a);
	if (a_pos < kh_end(island_marks))
		a_bitmap = kh_value(island_marks, a_pos);
 
	b_pos = kh_get_oid_map(island_marks, *b);
	if (b_pos < kh_end(island_marks))
		b_bitmap = kh_value(island_marks, b_pos);
 
	if (a_bitmap) {
		if (!b_bitmap || !island_bitmap_is_subset(a_bitmap, b_bitmap))
			return -1;
	}
	if (b_bitmap) {
		if (!a_bitmap || !island_bitmap_is_subset(b_bitmap, a_bitmap))
			return 1;
	}
 
	return 0;
}
 
static struct island_bitmap *create_or_get_island_marks(struct object *obj)
{
	khiter_t pos;
	int hash_ret;
 
	pos = kh_put_oid_map(island_marks, obj->oid, &hash_ret);
	if (hash_ret)
		kh_value(island_marks, pos) = island_bitmap_new(NULL);
 
	return kh_value(island_marks, pos);
}
 
static void set_island_marks(struct object *obj, struct island_bitmap *marks)
{
	struct island_bitmap *b;
	khiter_t pos;
	int hash_ret;
 
	pos = kh_put_oid_map(island_marks, obj->oid, &hash_ret);
	if (hash_ret) {
		/*
		 * We don't have one yet; make a copy-on-write of the
		 * parent.
		 */
		marks->refcount++;
		kh_value(island_marks, pos) = marks;
		return;
	}
 
	/*
	 * We do have it. Make sure we split any copy-on-write before
	 * updating.
	 */
	b = kh_value(island_marks, pos);
	if (b->refcount > 1) {
		b->refcount--;
		b = kh_value(island_marks, pos) = island_bitmap_new(b);
	}
	island_bitmap_or(b, marks);
}
 
static void mark_remote_island_1(struct repository *r,
				 struct remote_island *rl,
				 int is_core_island)
{
	uint32_t i;
 
	for (i = 0; i < rl->oids.nr; ++i) {
		struct island_bitmap *marks;
		struct object *obj = parse_object(r, &rl->oids.oid[i]);
 
		if (!obj)
			continue;
 
		marks = create_or_get_island_marks(obj);
		island_bitmap_set(marks, island_counter);
 
		if (is_core_island && obj->type == OBJ_COMMIT)
			obj->flags |= NEEDS_BITMAP;
 
		/* If it was a tag, also make sure we hit the underlying object. */
		while (obj && obj->type == OBJ_TAG) {
			obj = ((struct tag *)obj)->tagged;
			if (obj) {
				parse_object(r, &obj->oid);
				marks = create_or_get_island_marks(obj);
				island_bitmap_set(marks, island_counter);
			}
		}
	}
 
	if (is_core_island)
		island_counter_core = island_counter;
 
	island_counter++;
}
 
struct tree_islands_todo {
	struct object_entry *entry;
	unsigned int depth;
};
 
static int tree_depth_compare(const void *a, const void *b)
{
	const struct tree_islands_todo *todo_a = a;
	const struct tree_islands_todo *todo_b = b;
 
	return todo_a->depth - todo_b->depth;
}
 
void resolve_tree_islands(struct repository *r,
			  int progress,
			  struct packing_data *to_pack)
{
	struct progress *progress_state = NULL;
	struct tree_islands_todo *todo;
	int nr = 0;
	int i;
 
	if (!island_marks)
		return;
 
	/*
	 * We process only trees, as commits and tags have already been handled
	 * (and passed their marks on to root trees, as well. We must make sure
	 * to process them in descending tree-depth order so that marks
	 * propagate down the tree properly, even if a sub-tree is found in
	 * multiple parent trees.
	 */
	ALLOC_ARRAY(todo, to_pack->nr_objects);
	for (i = 0; i < to_pack->nr_objects; i++) {
		if (oe_type(&to_pack->objects[i]) == OBJ_TREE) {
			todo[nr].entry = &to_pack->objects[i];
			todo[nr].depth = oe_tree_depth(to_pack, &to_pack->objects[i]);
			nr++;
		}
	}
	QSORT(todo, nr, tree_depth_compare);
 
	if (progress)
		progress_state = start_progress(_("Propagating island marks"), nr);
 
	for (i = 0; i < nr; i++) {
		struct object_entry *ent = todo[i].entry;
		struct island_bitmap *root_marks;
		struct tree *tree;
		struct tree_desc desc;
		struct name_entry entry;
		khiter_t pos;
 
		pos = kh_get_oid_map(island_marks, ent->idx.oid);
		if (pos >= kh_end(island_marks))
			continue;
 
		root_marks = kh_value(island_marks, pos);
 
		tree = lookup_tree(r, &ent->idx.oid);
		if (!tree || parse_tree(tree) < 0)
			die(_("bad tree object %s"), oid_to_hex(&ent->idx.oid));
 
		init_tree_desc(&desc, tree->buffer, tree->size);
		while (tree_entry(&desc, &entry)) {
			struct object *obj;
 
			if (S_ISGITLINK(entry.mode))
				continue;
 
			obj = lookup_object(r, &entry.oid);
			if (!obj)
				continue;
 
			set_island_marks(obj, root_marks);
		}
 
		free_tree_buffer(tree);
 
		display_progress(progress_state, i+1);
	}
 
	stop_progress(&progress_state);
	free(todo);
}
 
static regex_t *island_regexes;
static unsigned int island_regexes_alloc, island_regexes_nr;
static const char *core_island_name;
 
static int island_config_callback(const char *k, const char *v, void *cb)
{
	if (!strcmp(k, "pack.island")) {
		struct strbuf re = STRBUF_INIT;
 
		if (!v)
			return config_error_nonbool(k);
 
		ALLOC_GROW(island_regexes, island_regexes_nr + 1, island_regexes_alloc);
 
		if (*v != '^')
			strbuf_addch(&re, '^');
		strbuf_addstr(&re, v);
 
		if (regcomp(&island_regexes[island_regexes_nr], re.buf, REG_EXTENDED))
			die(_("failed to load island regex for '%s': %s"), k, re.buf);
 
		strbuf_release(&re);
		island_regexes_nr++;
		return 0;
	}
 
	if (!strcmp(k, "pack.islandcore"))
		return git_config_string(&core_island_name, k, v);
 
	return 0;
}
 
static void add_ref_to_island(const char *island_name, const struct object_id *oid)
{
	uint64_t sha_core;
	struct remote_island *rl = NULL;
 
	int hash_ret;
	khiter_t pos = kh_put_str(remote_islands, island_name, &hash_ret);
 
	if (hash_ret) {
		kh_key(remote_islands, pos) = xstrdup(island_name);
		kh_value(remote_islands, pos) = xcalloc(1, sizeof(struct remote_island));
	}
 
	rl = kh_value(remote_islands, pos);
	oid_array_append(&rl->oids, oid);
 
	memcpy(&sha_core, oid->hash, sizeof(uint64_t));
	rl->hash += sha_core;
}
 
static int find_island_for_ref(const char *refname, const struct object_id *oid,
			       int flags, void *data)
{
	/*
	 * We should advertise 'ARRAY_SIZE(matches) - 2' as the max,
	 * so we can diagnose below a config with more capture groups
	 * than we support.
	 */
	regmatch_t matches[16];
	int i, m;
	struct strbuf island_name = STRBUF_INIT;
 
	/* walk backwards to get last-one-wins ordering */
	for (i = island_regexes_nr - 1; i >= 0; i--) {
		if (!regexec(&island_regexes[i], refname,
			     ARRAY_SIZE(matches), matches, 0))
			break;
	}
 
	if (i < 0)
		return 0;
 
	if (matches[ARRAY_SIZE(matches) - 1].rm_so != -1)
		warning(_("island regex from config has "
			  "too many capture groups (max=%d)"),
			(int)ARRAY_SIZE(matches) - 2);
 
	for (m = 1; m < ARRAY_SIZE(matches); m++) {
		regmatch_t *match = &matches[m];
 
		if (match->rm_so == -1)
			continue;
 
		if (island_name.len)
			strbuf_addch(&island_name, '-');
 
		strbuf_add(&island_name, refname + match->rm_so, match->rm_eo - match->rm_so);
	}
 
	add_ref_to_island(island_name.buf, oid);
	strbuf_release(&island_name);
	return 0;
}
 
static struct remote_island *get_core_island(void)
{
	if (core_island_name) {
		khiter_t pos = kh_get_str(remote_islands, core_island_name);
		if (pos < kh_end(remote_islands))
			return kh_value(remote_islands, pos);
	}
 
	return NULL;
}
 
static void deduplicate_islands(struct repository *r)
{
	struct remote_island *island, *core = NULL, **list;
	unsigned int island_count, dst, src, ref, i = 0;
 
	island_count = kh_size(remote_islands);
	ALLOC_ARRAY(list, island_count);
 
	kh_foreach_value(remote_islands, island, {
		list[i++] = island;
	});
 
	for (ref = 0; ref + 1 < island_count; ref++) {
		for (src = ref + 1, dst = src; src < island_count; src++) {
			if (list[ref]->hash == list[src]->hash)
				continue;
 
			if (src != dst)
				list[dst] = list[src];
 
			dst++;
		}
		island_count = dst;
	}
 
	island_bitmap_size = (island_count / 32) + 1;
	core = get_core_island();
 
	for (i = 0; i < island_count; ++i) {
		mark_remote_island_1(r, list[i], core && list[i]->hash == core->hash);
	}
 
	free(list);
}
 
void load_delta_islands(struct repository *r, int progress)
{
	island_marks = kh_init_oid_map();
	remote_islands = kh_init_str();
 
	git_config(island_config_callback, NULL);
	for_each_ref(find_island_for_ref, NULL);
	deduplicate_islands(r);
 
	if (progress)
		fprintf(stderr, _("Marked %d islands, done.\n"), island_counter);
}
 
void propagate_island_marks(struct commit *commit)
{
	khiter_t pos = kh_get_oid_map(island_marks, commit->object.oid);
 
	if (pos < kh_end(island_marks)) {
		struct commit_list *p;
		struct island_bitmap *root_marks = kh_value(island_marks, pos);
 
		parse_commit(commit);
		set_island_marks(&get_commit_tree(commit)->object, root_marks);
		for (p = commit->parents; p; p = p->next)
			set_island_marks(&p->item->object, root_marks);
	}
}
 
int compute_pack_layers(struct packing_data *to_pack)
{
	uint32_t i;
 
	if (!core_island_name || !island_marks)
		return 1;
 
	for (i = 0; i < to_pack->nr_objects; ++i) {
		struct object_entry *entry = &to_pack->objects[i];
		khiter_t pos = kh_get_oid_map(island_marks, entry->idx.oid);
 
		oe_set_layer(to_pack, entry, 1);
 
		if (pos < kh_end(island_marks)) {
			struct island_bitmap *bitmap = kh_value(island_marks, pos);
 
			if (island_bitmap_get(bitmap, island_counter_core))
				oe_set_layer(to_pack, entry, 0);
		}
	}
 
	return 2;
}