[thirdparty/git.git] / pack-bitmap-write.c

#include "cache.h"
#include "object-store.h"
#include "commit.h"
#include "tag.h"
#include "diff.h"
#include "revision.h"
#include "list-objects.h"
#include "progress.h"
#include "pack-revindex.h"
#include "pack.h"
#include "pack-bitmap.h"
#include "sha1-lookup.h"
#include "pack-objects.h"

struct bitmapped_commit {
	struct commit *commit;
	struct ewah_bitmap *bitmap;
	struct ewah_bitmap *write_as;
	int flags;
	int xor_offset;
	uint32_t commit_pos;
};

struct bitmap_writer {
	struct ewah_bitmap *commits;
	struct ewah_bitmap *trees;
	struct ewah_bitmap *blobs;
	struct ewah_bitmap *tags;

	khash_sha1 *bitmaps;
	khash_sha1 *reused;
	struct packing_data *to_pack;

	struct bitmapped_commit *selected;
	unsigned int selected_nr, selected_alloc;

	struct progress *progress;
	int show_progress;
	unsigned char pack_checksum[20];
};

static struct bitmap_writer writer;

void bitmap_writer_show_progress(int show)
{
	writer.show_progress = show;
}

/**
 * Build the initial type index for the packfile
 */
void bitmap_writer_build_type_index(struct packing_data *to_pack,
				    struct pack_idx_entry **index,
				    uint32_t index_nr)
{
	uint32_t i;

	writer.commits = ewah_new();
	writer.trees = ewah_new();
	writer.blobs = ewah_new();
	writer.tags = ewah_new();
	ALLOC_ARRAY(to_pack->in_pack_pos, to_pack->nr_objects);

	for (i = 0; i < index_nr; ++i) {
		struct object_entry *entry = (struct object_entry *)index[i];
		enum object_type real_type;

		oe_set_in_pack_pos(to_pack, entry, i);

		switch (oe_type(entry)) {
		case OBJ_COMMIT:
		case OBJ_TREE:
		case OBJ_BLOB:
		case OBJ_TAG:
			real_type = oe_type(entry);
			break;

		default:
			real_type = oid_object_info(the_repository,
						    &entry->idx.oid, NULL);
			break;
		}

		switch (real_type) {
		case OBJ_COMMIT:
			ewah_set(writer.commits, i);
			break;

		case OBJ_TREE:
			ewah_set(writer.trees, i);
			break;

		case OBJ_BLOB:
			ewah_set(writer.blobs, i);
			break;

		case OBJ_TAG:
			ewah_set(writer.tags, i);
			break;

		default:
			die("Missing type information for %s (%d/%d)",
			    oid_to_hex(&entry->idx.oid), real_type,
			    oe_type(entry));
		}
	}
}

/**
 * Compute the actual bitmaps
 */
static struct object **seen_objects;
static unsigned int seen_objects_nr, seen_objects_alloc;

static inline void push_bitmapped_commit(struct commit *commit, struct ewah_bitmap *reused)
{
	if (writer.selected_nr >= writer.selected_alloc) {
		writer.selected_alloc = (writer.selected_alloc + 32) * 2;
		REALLOC_ARRAY(writer.selected, writer.selected_alloc);
	}

	writer.selected[writer.selected_nr].commit = commit;
	writer.selected[writer.selected_nr].bitmap = reused;
	writer.selected[writer.selected_nr].flags = 0;

	writer.selected_nr++;
}

static inline void mark_as_seen(struct object *object)
{
	ALLOC_GROW(seen_objects, seen_objects_nr + 1, seen_objects_alloc);
	seen_objects[seen_objects_nr++] = object;
}

static inline void reset_all_seen(void)
{
	unsigned int i;
	for (i = 0; i < seen_objects_nr; ++i) {
		seen_objects[i]->flags &= ~(SEEN | ADDED | SHOWN);
	}
	seen_objects_nr = 0;
}

static uint32_t find_object_pos(const unsigned char *sha1)
{
	struct object_entry *entry = packlist_find(writer.to_pack, sha1, NULL);

	if (!entry) {
		die("Failed to write bitmap index. Packfile doesn't have full closure "
			"(object %s is missing)", sha1_to_hex(sha1));
	}

	return oe_in_pack_pos(writer.to_pack, entry);
}

static void show_object(struct object *object, const char *name, void *data)
{
	struct bitmap *base = data;
	bitmap_set(base, find_object_pos(object->oid.hash));
	mark_as_seen(object);
}

static void show_commit(struct commit *commit, void *data)
{
	mark_as_seen((struct object *)commit);
}

static int
add_to_include_set(struct bitmap *base, struct commit *commit)
{
	khiter_t hash_pos;
	uint32_t bitmap_pos = find_object_pos(commit->object.oid.hash);

	if (bitmap_get(base, bitmap_pos))
		return 0;

	hash_pos = kh_get_sha1(writer.bitmaps, commit->object.oid.hash);
	if (hash_pos < kh_end(writer.bitmaps)) {
		struct bitmapped_commit *bc = kh_value(writer.bitmaps, hash_pos);
		bitmap_or_ewah(base, bc->bitmap);
		return 0;
	}

	bitmap_set(base, bitmap_pos);
	return 1;
}

static int
should_include(struct commit *commit, void *_data)
{
	struct bitmap *base = _data;

	if (!add_to_include_set(base, commit)) {
		struct commit_list *parent = commit->parents;

		mark_as_seen((struct object *)commit);

		while (parent) {
			parent->item->object.flags |= SEEN;
			mark_as_seen((struct object *)parent->item);
			parent = parent->next;
		}

		return 0;
	}

	return 1;
}

static void compute_xor_offsets(void)
{
	static const int MAX_XOR_OFFSET_SEARCH = 10;

	int i, next = 0;

	while (next < writer.selected_nr) {
		struct bitmapped_commit *stored = &writer.selected[next];

		int best_offset = 0;
		struct ewah_bitmap *best_bitmap = stored->bitmap;
		struct ewah_bitmap *test_xor;

		for (i = 1; i <= MAX_XOR_OFFSET_SEARCH; ++i) {
			int curr = next - i;

			if (curr < 0)
				break;

			test_xor = ewah_pool_new();
			ewah_xor(writer.selected[curr].bitmap, stored->bitmap, test_xor);

			if (test_xor->buffer_size < best_bitmap->buffer_size) {
				if (best_bitmap != stored->bitmap)
					ewah_pool_free(best_bitmap);

				best_bitmap = test_xor;
				best_offset = i;
			} else {
				ewah_pool_free(test_xor);
			}
		}

		stored->xor_offset = best_offset;
		stored->write_as = best_bitmap;

		next++;
	}
}

void bitmap_writer_build(struct packing_data *to_pack)
{
	static const double REUSE_BITMAP_THRESHOLD = 0.2;

	int i, reuse_after, need_reset;
	struct bitmap *base = bitmap_new();
	struct rev_info revs;

	writer.bitmaps = kh_init_sha1();
	writer.to_pack = to_pack;

	if (writer.show_progress)
		writer.progress = start_progress("Building bitmaps", writer.selected_nr);

	init_revisions(&revs, NULL);
	revs.tag_objects = 1;
	revs.tree_objects = 1;
	revs.blob_objects = 1;
	revs.no_walk = 0;

	revs.include_check = should_include;
	reset_revision_walk();

	reuse_after = writer.selected_nr * REUSE_BITMAP_THRESHOLD;
	need_reset = 0;

	for (i = writer.selected_nr - 1; i >= 0; --i) {
		struct bitmapped_commit *stored;
		struct object *object;

		khiter_t hash_pos;
		int hash_ret;

		stored = &writer.selected[i];
		object = (struct object *)stored->commit;

		if (stored->bitmap == NULL) {
			if (i < writer.selected_nr - 1 &&
			    (need_reset ||
			     !in_merge_bases(writer.selected[i + 1].commit,
					     stored->commit))) {
			    bitmap_reset(base);
			    reset_all_seen();
			}

			add_pending_object(&revs, object, "");
			revs.include_check_data = base;

			if (prepare_revision_walk(&revs))
				die("revision walk setup failed");

			traverse_commit_list(&revs, show_commit, show_object, base);

			object_array_clear(&revs.pending);

			stored->bitmap = bitmap_to_ewah(base);
			need_reset = 0;
		} else
			need_reset = 1;

		if (i >= reuse_after)
			stored->flags |= BITMAP_FLAG_REUSE;

		hash_pos = kh_put_sha1(writer.bitmaps, object->oid.hash, &hash_ret);
		if (hash_ret == 0)
			die("Duplicate entry when writing index: %s",
			    oid_to_hex(&object->oid));

		kh_value(writer.bitmaps, hash_pos) = stored;
		display_progress(writer.progress, writer.selected_nr - i);
	}

	bitmap_free(base);
	stop_progress(&writer.progress);

	compute_xor_offsets();
}

/**
 * Select the commits that will be bitmapped
 */
static inline unsigned int next_commit_index(unsigned int idx)
{
	static const unsigned int MIN_COMMITS = 100;
	static const unsigned int MAX_COMMITS = 5000;

	static const unsigned int MUST_REGION = 100;
	static const unsigned int MIN_REGION = 20000;

	unsigned int offset, next;

	if (idx <= MUST_REGION)
		return 0;

	if (idx <= MIN_REGION) {
		offset = idx - MUST_REGION;
		return (offset < MIN_COMMITS) ? offset : MIN_COMMITS;
	}

	offset = idx - MIN_REGION;
	next = (offset < MAX_COMMITS) ? offset : MAX_COMMITS;

	return (next > MIN_COMMITS) ? next : MIN_COMMITS;
}

static int date_compare(const void *_a, const void *_b)
{
	struct commit *a = *(struct commit **)_a;
	struct commit *b = *(struct commit **)_b;
	return (long)b->date - (long)a->date;
}

void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack)
{
	if (prepare_bitmap_git() < 0)
		return;

	writer.reused = kh_init_sha1();
	rebuild_existing_bitmaps(to_pack, writer.reused, writer.show_progress);
}

static struct ewah_bitmap *find_reused_bitmap(const unsigned char *sha1)
{
	khiter_t hash_pos;

	if (!writer.reused)
		return NULL;

	hash_pos = kh_get_sha1(writer.reused, sha1);
	if (hash_pos >= kh_end(writer.reused))
		return NULL;

	return kh_value(writer.reused, hash_pos);
}

void bitmap_writer_select_commits(struct commit **indexed_commits,
				  unsigned int indexed_commits_nr,
				  int max_bitmaps)
{
	unsigned int i = 0, j, next;

	QSORT(indexed_commits, indexed_commits_nr, date_compare);

	if (writer.show_progress)
		writer.progress = start_progress("Selecting bitmap commits", 0);

	if (indexed_commits_nr < 100) {
		for (i = 0; i < indexed_commits_nr; ++i)
			push_bitmapped_commit(indexed_commits[i], NULL);
		return;
	}

	for (;;) {
		struct ewah_bitmap *reused_bitmap = NULL;
		struct commit *chosen = NULL;

		next = next_commit_index(i);

		if (i + next >= indexed_commits_nr)
			break;

		if (max_bitmaps > 0 && writer.selected_nr >= max_bitmaps) {
			writer.selected_nr = max_bitmaps;
			break;
		}

		if (next == 0) {
			chosen = indexed_commits[i];
			reused_bitmap = find_reused_bitmap(chosen->object.oid.hash);
		} else {
			chosen = indexed_commits[i + next];

			for (j = 0; j <= next; ++j) {
				struct commit *cm = indexed_commits[i + j];

				reused_bitmap = find_reused_bitmap(cm->object.oid.hash);
				if (reused_bitmap || (cm->object.flags & NEEDS_BITMAP) != 0) {
					chosen = cm;
					break;
				}

				if (cm->parents && cm->parents->next)
					chosen = cm;
			}
		}

		push_bitmapped_commit(chosen, reused_bitmap);

		i += next + 1;
		display_progress(writer.progress, i);
	}

	stop_progress(&writer.progress);
}


static int hashwrite_ewah_helper(void *f, const void *buf, size_t len)
{
	/* hashwrite will die on error */
	hashwrite(f, buf, len);
	return len;
}

/**
 * Write the bitmap index to disk
 */
static inline void dump_bitmap(struct hashfile *f, struct ewah_bitmap *bitmap)
{
	if (ewah_serialize_to(bitmap, hashwrite_ewah_helper, f) < 0)
		die("Failed to write bitmap index");
}

static const unsigned char *sha1_access(size_t pos, void *table)
{
	struct pack_idx_entry **index = table;
	return index[pos]->oid.hash;
}

static void write_selected_commits_v1(struct hashfile *f,
				      struct pack_idx_entry **index,
				      uint32_t index_nr)
{
	int i;

	for (i = 0; i < writer.selected_nr; ++i) {
		struct bitmapped_commit *stored = &writer.selected[i];

		int commit_pos =
			sha1_pos(stored->commit->object.oid.hash, index, index_nr, sha1_access);

		if (commit_pos < 0)
			BUG("trying to write commit not in index");

		hashwrite_be32(f, commit_pos);
		hashwrite_u8(f, stored->xor_offset);
		hashwrite_u8(f, stored->flags);

		dump_bitmap(f, stored->write_as);
	}
}

static void write_hash_cache(struct hashfile *f,
			     struct pack_idx_entry **index,
			     uint32_t index_nr)
{
	uint32_t i;

	for (i = 0; i < index_nr; ++i) {
		struct object_entry *entry = (struct object_entry *)index[i];
		uint32_t hash_value = htonl(entry->hash);
		hashwrite(f, &hash_value, sizeof(hash_value));
	}
}

void bitmap_writer_set_checksum(unsigned char *sha1)
{
	hashcpy(writer.pack_checksum, sha1);
}

void bitmap_writer_finish(struct pack_idx_entry **index,
			  uint32_t index_nr,
			  const char *filename,
			  uint16_t options)
{
	static uint16_t default_version = 1;
	static uint16_t flags = BITMAP_OPT_FULL_DAG;
	struct strbuf tmp_file = STRBUF_INIT;
	struct hashfile *f;

	struct bitmap_disk_header header;

	int fd = odb_mkstemp(&tmp_file, "pack/tmp_bitmap_XXXXXX");

	f = hashfd(fd, tmp_file.buf);

	memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
	header.version = htons(default_version);
	header.options = htons(flags | options);
	header.entry_count = htonl(writer.selected_nr);
	hashcpy(header.checksum, writer.pack_checksum);

	hashwrite(f, &header, sizeof(header));
	dump_bitmap(f, writer.commits);
	dump_bitmap(f, writer.trees);
	dump_bitmap(f, writer.blobs);
	dump_bitmap(f, writer.tags);
	write_selected_commits_v1(f, index, index_nr);

	if (options & BITMAP_OPT_HASH_CACHE)
		write_hash_cache(f, index, index_nr);

	finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);

	if (adjust_shared_perm(tmp_file.buf))
		die_errno("unable to make temporary bitmap file readable");

	if (rename(tmp_file.buf, filename))
		die_errno("unable to rename temporary bitmap file to '%s'", filename);

	strbuf_release(&tmp_file);
}
Commit	Line	Data
7cc8f971	1	#include "cache.h"
cbd53a21	2	#include "object-store.h"
7cc8f971 VM	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
	15	struct bitmapped_commit {
	16	struct commit *commit;
	17	struct ewah_bitmap *bitmap;
	18	struct ewah_bitmap *write_as;
	19	int flags;
	20	int xor_offset;
	21	uint32_t commit_pos;
	22	};
	23
	24	struct bitmap_writer {
	25	struct ewah_bitmap *commits;
	26	struct ewah_bitmap *trees;
	27	struct ewah_bitmap *blobs;
	28	struct ewah_bitmap *tags;
	29
	30	khash_sha1 *bitmaps;
	31	khash_sha1 *reused;
	32	struct packing_data *to_pack;
	33
	34	struct bitmapped_commit *selected;
	35	unsigned int selected_nr, selected_alloc;
	36
	37	struct progress *progress;
	38	int show_progress;
	39	unsigned char pack_checksum[20];
	40	};
	41
	42	static struct bitmap_writer writer;
	43
	44	void bitmap_writer_show_progress(int show)
	45	{
	46	writer.show_progress = show;
	47	}
	48
	49	/**
	50	* Build the initial type index for the packfile
	51	*/
06af3bba NTND	52	void bitmap_writer_build_type_index(struct packing_data *to_pack,
06af3bba NTND	53	struct pack_idx_entry **index,
7cc8f971 VM	54	uint32_t index_nr)
	55	{
	56	uint32_t i;
	57
	58	writer.commits = ewah_new();
	59	writer.trees = ewah_new();
	60	writer.blobs = ewah_new();
	61	writer.tags = ewah_new();
06af3bba	62	ALLOC_ARRAY(to_pack->in_pack_pos, to_pack->nr_objects);
7cc8f971 VM	63
	64	for (i = 0; i < index_nr; ++i) {
	65	struct object_entry entry = (struct object_entry )index[i];
	66	enum object_type real_type;
	67
06af3bba	68	oe_set_in_pack_pos(to_pack, entry, i);
7cc8f971	69
fd9b1bae	70	switch (oe_type(entry)) {
7cc8f971 VM	71	case OBJ_COMMIT:
	72	case OBJ_TREE:
	73	case OBJ_BLOB:
	74	case OBJ_TAG:
fd9b1bae	75	real_type = oe_type(entry);
7cc8f971 VM	76	break;
	77
	78	default:
0df8e965 SB	79	real_type = oid_object_info(the_repository,
0df8e965 SB	80	&entry->idx.oid, NULL);
7cc8f971 VM	81	break;
	82	}
	83
	84	switch (real_type) {
	85	case OBJ_COMMIT:
	86	ewah_set(writer.commits, i);
	87	break;
	88
	89	case OBJ_TREE:
	90	ewah_set(writer.trees, i);
	91	break;
	92
	93	case OBJ_BLOB:
	94	ewah_set(writer.blobs, i);
	95	break;
	96
	97	case OBJ_TAG:
	98	ewah_set(writer.tags, i);
	99	break;
	100
	101	default:
	102	die("Missing type information for %s (%d/%d)",
e6a492b7	103	oid_to_hex(&entry->idx.oid), real_type,
fd9b1bae	104	oe_type(entry));
7cc8f971 VM	105	}
	106	}
	107	}
	108
	109	/**
	110	* Compute the actual bitmaps
	111	*/
	112	static struct object **seen_objects;
	113	static unsigned int seen_objects_nr, seen_objects_alloc;
	114
	115	static inline void push_bitmapped_commit(struct commit commit, struct ewah_bitmap reused)
	116	{
	117	if (writer.selected_nr >= writer.selected_alloc) {
	118	writer.selected_alloc = (writer.selected_alloc + 32) * 2;
2756ca43	119	REALLOC_ARRAY(writer.selected, writer.selected_alloc);
7cc8f971 VM	120	}
	121
	122	writer.selected[writer.selected_nr].commit = commit;
	123	writer.selected[writer.selected_nr].bitmap = reused;
	124	writer.selected[writer.selected_nr].flags = 0;
	125
	126	writer.selected_nr++;
	127	}
	128
	129	static inline void mark_as_seen(struct object *object)
	130	{
	131	ALLOC_GROW(seen_objects, seen_objects_nr + 1, seen_objects_alloc);
	132	seen_objects[seen_objects_nr++] = object;
	133	}
	134
	135	static inline void reset_all_seen(void)
	136	{
	137	unsigned int i;
	138	for (i = 0; i < seen_objects_nr; ++i) {
	139	seen_objects[i]->flags &= ~(SEEN \| ADDED \| SHOWN);
	140	}
	141	seen_objects_nr = 0;
	142	}
	143
	144	static uint32_t find_object_pos(const unsigned char *sha1)
	145	{
	146	struct object_entry *entry = packlist_find(writer.to_pack, sha1, NULL);
	147
	148	if (!entry) {
	149	die("Failed to write bitmap index. Packfile doesn't have full closure "
	150	"(object %s is missing)", sha1_to_hex(sha1));
	151	}
	152
06af3bba	153	return oe_in_pack_pos(writer.to_pack, entry);
7cc8f971 VM	154	}
7cc8f971 VM	155
de1e67d0	156	static void show_object(struct object object, const char name, void *data)
7cc8f971 VM	157	{
7cc8f971 VM	158	struct bitmap *base = data;
ed1c9977	159	bitmap_set(base, find_object_pos(object->oid.hash));
7cc8f971 VM	160	mark_as_seen(object);
	161	}
	162
	163	static void show_commit(struct commit commit, void data)
	164	{
	165	mark_as_seen((struct object *)commit);
	166	}
	167
	168	static int
	169	add_to_include_set(struct bitmap base, struct commit commit)
	170	{
	171	khiter_t hash_pos;
ed1c9977	172	uint32_t bitmap_pos = find_object_pos(commit->object.oid.hash);
7cc8f971 VM	173
	174	if (bitmap_get(base, bitmap_pos))
	175	return 0;
	176
ed1c9977	177	hash_pos = kh_get_sha1(writer.bitmaps, commit->object.oid.hash);
7cc8f971 VM	178	if (hash_pos < kh_end(writer.bitmaps)) {
	179	struct bitmapped_commit *bc = kh_value(writer.bitmaps, hash_pos);
	180	bitmap_or_ewah(base, bc->bitmap);
	181	return 0;
	182	}
	183
	184	bitmap_set(base, bitmap_pos);
	185	return 1;
	186	}
	187
	188	static int
	189	should_include(struct commit commit, void _data)
	190	{
	191	struct bitmap *base = _data;
	192
	193	if (!add_to_include_set(base, commit)) {
	194	struct commit_list *parent = commit->parents;
	195
	196	mark_as_seen((struct object *)commit);
	197
	198	while (parent) {
	199	parent->item->object.flags \|= SEEN;
	200	mark_as_seen((struct object *)parent->item);
	201	parent = parent->next;
	202	}
	203
	204	return 0;
	205	}
	206
	207	return 1;
	208	}
	209
	210	static void compute_xor_offsets(void)
	211	{
	212	static const int MAX_XOR_OFFSET_SEARCH = 10;
	213
	214	int i, next = 0;
	215
	216	while (next < writer.selected_nr) {
	217	struct bitmapped_commit *stored = &writer.selected[next];
	218
	219	int best_offset = 0;
	220	struct ewah_bitmap *best_bitmap = stored->bitmap;
	221	struct ewah_bitmap *test_xor;
	222
	223	for (i = 1; i <= MAX_XOR_OFFSET_SEARCH; ++i) {
	224	int curr = next - i;
	225
	226	if (curr < 0)
	227	break;
	228
	229	test_xor = ewah_pool_new();
	230	ewah_xor(writer.selected[curr].bitmap, stored->bitmap, test_xor);
	231
	232	if (test_xor->buffer_size < best_bitmap->buffer_size) {
	233	if (best_bitmap != stored->bitmap)
	234	ewah_pool_free(best_bitmap);
	235
	236	best_bitmap = test_xor;
	237	best_offset = i;
	238	} else {
	239	ewah_pool_free(test_xor);
	240	}
	241	}
242
243	stored->xor_offset = best_offset;
244	stored->write_as = best_bitmap;
245
246	next++;
247	}
248	}
249
250	void bitmap_writer_build(struct packing_data *to_pack)
251	{
252	static const double REUSE_BITMAP_THRESHOLD = 0.2;
253
254	int i, reuse_after, need_reset;
255	struct bitmap *base = bitmap_new();
256	struct rev_info revs;
257
258	writer.bitmaps = kh_init_sha1();
259	writer.to_pack = to_pack;
260
261	if (writer.show_progress)
262	writer.progress = start_progress("Building bitmaps", writer.selected_nr);
263
264	init_revisions(&revs, NULL);
265	revs.tag_objects = 1;
266	revs.tree_objects = 1;
267	revs.blob_objects = 1;
268	revs.no_walk = 0;
269
270	revs.include_check = should_include;
271	reset_revision_walk();
272
273	reuse_after = writer.selected_nr * REUSE_BITMAP_THRESHOLD;
274	need_reset = 0;
275
276	for (i = writer.selected_nr - 1; i >= 0; --i) {
277	struct bitmapped_commit *stored;
278	struct object *object;
279
280	khiter_t hash_pos;
281	int hash_ret;
282
283	stored = &writer.selected[i];
284	object = (struct object *)stored->commit;
285
286	if (stored->bitmap == NULL) {
287	if (i < writer.selected_nr - 1 &&
288	(need_reset \|\|
289	!in_merge_bases(writer.selected[i + 1].commit,
290	stored->commit))) {
291	bitmap_reset(base);
292	reset_all_seen();
293	}
294
295	add_pending_object(&revs, object, "");
296	revs.include_check_data = base;
297
298	if (prepare_revision_walk(&revs))
299	die("revision walk setup failed");
300
301	traverse_commit_list(&revs, show_commit, show_object, base);
302
4d01a7fa	303	object_array_clear(&revs.pending);
7cc8f971 VM	304
	305	stored->bitmap = bitmap_to_ewah(base);
	306	need_reset = 0;
	307	} else
	308	need_reset = 1;
	309
	310	if (i >= reuse_after)
	311	stored->flags \|= BITMAP_FLAG_REUSE;
	312
ed1c9977	313	hash_pos = kh_put_sha1(writer.bitmaps, object->oid.hash, &hash_ret);
7cc8f971 VM	314	if (hash_ret == 0)
7cc8f971 VM	315	die("Duplicate entry when writing index: %s",
f2fd0760	316	oid_to_hex(&object->oid));
7cc8f971 VM	317
	318	kh_value(writer.bitmaps, hash_pos) = stored;
	319	display_progress(writer.progress, writer.selected_nr - i);
	320	}
	321
	322	bitmap_free(base);
	323	stop_progress(&writer.progress);
	324
	325	compute_xor_offsets();
	326	}
	327
	328	/**
	329	* Select the commits that will be bitmapped
	330	*/
	331	static inline unsigned int next_commit_index(unsigned int idx)
	332	{
	333	static const unsigned int MIN_COMMITS = 100;
	334	static const unsigned int MAX_COMMITS = 5000;
	335
	336	static const unsigned int MUST_REGION = 100;
	337	static const unsigned int MIN_REGION = 20000;
	338
	339	unsigned int offset, next;
	340
	341	if (idx <= MUST_REGION)
	342	return 0;
	343
	344	if (idx <= MIN_REGION) {
	345	offset = idx - MUST_REGION;
	346	return (offset < MIN_COMMITS) ? offset : MIN_COMMITS;
	347	}
	348
	349	offset = idx - MIN_REGION;
	350	next = (offset < MAX_COMMITS) ? offset : MAX_COMMITS;
	351
	352	return (next > MIN_COMMITS) ? next : MIN_COMMITS;
	353	}
	354
	355	static int date_compare(const void _a, const void _b)
	356	{
	357	struct commit a = (struct commit **)_a;
	358	struct commit b = (struct commit **)_b;
	359	return (long)b->date - (long)a->date;
	360	}
	361
	362	void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack)
	363	{
	364	if (prepare_bitmap_git() < 0)
	365	return;
	366
	367	writer.reused = kh_init_sha1();
	368	rebuild_existing_bitmaps(to_pack, writer.reused, writer.show_progress);
	369	}
	370
	371	static struct ewah_bitmap find_reused_bitmap(const unsigned char sha1)
	372	{
	373	khiter_t hash_pos;
	374
	375	if (!writer.reused)
	376	return NULL;
	377
	378	hash_pos = kh_get_sha1(writer.reused, sha1);
	379	if (hash_pos >= kh_end(writer.reused))
	380	return NULL;
381
382	return kh_value(writer.reused, hash_pos);
383	}
384
385	void bitmap_writer_select_commits(struct commit **indexed_commits,
386	unsigned int indexed_commits_nr,
387	int max_bitmaps)
388	{
389	unsigned int i = 0, j, next;
390
9ed0d8d6	391	QSORT(indexed_commits, indexed_commits_nr, date_compare);
7cc8f971 VM	392
	393	if (writer.show_progress)
	394	writer.progress = start_progress("Selecting bitmap commits", 0);
	395
	396	if (indexed_commits_nr < 100) {
	397	for (i = 0; i < indexed_commits_nr; ++i)
	398	push_bitmapped_commit(indexed_commits[i], NULL);
	399	return;
	400	}
	401
	402	for (;;) {
	403	struct ewah_bitmap *reused_bitmap = NULL;
	404	struct commit *chosen = NULL;
	405
	406	next = next_commit_index(i);
	407
	408	if (i + next >= indexed_commits_nr)
	409	break;
	410
	411	if (max_bitmaps > 0 && writer.selected_nr >= max_bitmaps) {
	412	writer.selected_nr = max_bitmaps;
	413	break;
	414	}
	415
	416	if (next == 0) {
	417	chosen = indexed_commits[i];
ed1c9977	418	reused_bitmap = find_reused_bitmap(chosen->object.oid.hash);
7cc8f971 VM	419	} else {
	420	chosen = indexed_commits[i + next];
	421
	422	for (j = 0; j <= next; ++j) {
	423	struct commit *cm = indexed_commits[i + j];
	424
ed1c9977	425	reused_bitmap = find_reused_bitmap(cm->object.oid.hash);
7cc8f971 VM	426	if (reused_bitmap \|\| (cm->object.flags & NEEDS_BITMAP) != 0) {
	427	chosen = cm;
	428	break;
	429	}
	430
	431	if (cm->parents && cm->parents->next)
	432	chosen = cm;
	433	}
	434	}
	435
	436	push_bitmapped_commit(chosen, reused_bitmap);
	437
	438	i += next + 1;
	439	display_progress(writer.progress, i);
	440	}
	441
	442	stop_progress(&writer.progress);
	443	}
	444
	445
98a3beab	446	static int hashwrite_ewah_helper(void f, const void buf, size_t len)
7cc8f971	447	{
98a3beab	448	/* hashwrite will die on error */
98a3beab	449	hashwrite(f, buf, len);
7cc8f971 VM	450	return len;
	451	}
	452
	453	/**
	454	* Write the bitmap index to disk
	455	*/
98a3beab	456	static inline void dump_bitmap(struct hashfile f, struct ewah_bitmap bitmap)
7cc8f971	457	{
98a3beab	458	if (ewah_serialize_to(bitmap, hashwrite_ewah_helper, f) < 0)
7cc8f971 VM	459	die("Failed to write bitmap index");
	460	}
	461
	462	static const unsigned char sha1_access(size_t pos, void table)
	463	{
	464	struct pack_idx_entry **index = table;
e6a492b7	465	return index[pos]->oid.hash;
7cc8f971 VM	466	}
7cc8f971 VM	467
98a3beab	468	static void write_selected_commits_v1(struct hashfile *f,
7cc8f971 VM	469	struct pack_idx_entry **index,
	470	uint32_t index_nr)
	471	{
	472	int i;
	473
	474	for (i = 0; i < writer.selected_nr; ++i) {
	475	struct bitmapped_commit *stored = &writer.selected[i];
7cc8f971 VM	476
7cc8f971 VM	477	int commit_pos =
ed1c9977	478	sha1_pos(stored->commit->object.oid.hash, index, index_nr, sha1_access);
7cc8f971 VM	479
7cc8f971 VM	480	if (commit_pos < 0)
033abf97	481	BUG("trying to write commit not in index");
7cc8f971	482
98a3beab	483	hashwrite_be32(f, commit_pos);
	484	hashwrite_u8(f, stored->xor_offset);
	485	hashwrite_u8(f, stored->flags);
7cc8f971	486
7cc8f971 VM	487	dump_bitmap(f, stored->write_as);
	488	}
	489	}
	490
98a3beab	491	static void write_hash_cache(struct hashfile *f,
ae4f07fb VM	492	struct pack_idx_entry **index,
	493	uint32_t index_nr)
	494	{
	495	uint32_t i;
	496
	497	for (i = 0; i < index_nr; ++i) {
	498	struct object_entry entry = (struct object_entry )index[i];
	499	uint32_t hash_value = htonl(entry->hash);
98a3beab	500	hashwrite(f, &hash_value, sizeof(hash_value));
ae4f07fb VM	501	}
	502	}
	503
7cc8f971 VM	504	void bitmap_writer_set_checksum(unsigned char *sha1)
	505	{
	506	hashcpy(writer.pack_checksum, sha1);
	507	}
	508
	509	void bitmap_writer_finish(struct pack_idx_entry **index,
	510	uint32_t index_nr,
ae4f07fb VM	511	const char *filename,
ae4f07fb VM	512	uint16_t options)
7cc8f971	513	{
7cc8f971 VM	514	static uint16_t default_version = 1;
7cc8f971 VM	515	static uint16_t flags = BITMAP_OPT_FULL_DAG;
594fa999	516	struct strbuf tmp_file = STRBUF_INIT;
98a3beab	517	struct hashfile *f;
7cc8f971 VM	518
	519	struct bitmap_disk_header header;
	520
594fa999	521	int fd = odb_mkstemp(&tmp_file, "pack/tmp_bitmap_XXXXXX");
7cc8f971	522
98a3beab	523	f = hashfd(fd, tmp_file.buf);
7cc8f971 VM	524
	525	memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
	526	header.version = htons(default_version);
ae4f07fb	527	header.options = htons(flags \| options);
7cc8f971	528	header.entry_count = htonl(writer.selected_nr);
50546b15	529	hashcpy(header.checksum, writer.pack_checksum);
7cc8f971	530
98a3beab	531	hashwrite(f, &header, sizeof(header));
7cc8f971 VM	532	dump_bitmap(f, writer.commits);
	533	dump_bitmap(f, writer.trees);
	534	dump_bitmap(f, writer.blobs);
	535	dump_bitmap(f, writer.tags);
	536	write_selected_commits_v1(f, index, index_nr);
	537
ae4f07fb VM	538	if (options & BITMAP_OPT_HASH_CACHE)
	539	write_hash_cache(f, index, index_nr);
	540
cfe83216	541	finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM \| CSUM_FSYNC \| CSUM_CLOSE);
7cc8f971	542
594fa999	543	if (adjust_shared_perm(tmp_file.buf))
7cc8f971 VM	544	die_errno("unable to make temporary bitmap file readable");
7cc8f971 VM	545
594fa999	546	if (rename(tmp_file.buf, filename))
7cc8f971	547	die_errno("unable to rename temporary bitmap file to '%s'", filename);
594fa999 JK	548
594fa999 JK	549	strbuf_release(&tmp_file);
7cc8f971	550	}