git@vger.kernel.org list mirror (unofficial, one of many)
 help / color / mirror / Atom feed
6d5d6bb2efbbb8c149f20a9efbbeee461edffb79 blob 6956 bytes (raw)

  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
 
#include "git-compat-util.h"
#include "bloom.h"
#include "commit.h"
#include "commit-slab.h"
#include "commit-graph.h"
#include "object-store.h"
#include "diff.h"
#include "diffcore.h"
#include "revision.h"
#include "hashmap.h"

define_commit_slab(bloom_filter_slab, struct bloom_filter);

struct bloom_filter_slab bloom_filters;

struct pathmap_hash_entry {
    struct hashmap_entry entry;
    const char path[FLEX_ARRAY];
};

static uint32_t rotate_right(uint32_t value, int32_t count)
{
	uint32_t mask = 8 * sizeof(uint32_t) - 1;
	count &= mask;
	return ((value >> count) | (value << ((-count) & mask)));
}

/*
 * Calculate a hash value for the given data using the given seed.
 * Produces a uniformly distributed hash value.
 * Not considered to be cryptographically secure.
 * Implemented as described in https://en.wikipedia.org/wiki/MurmurHash#Algorithm
 **/
static uint32_t seed_murmur3(uint32_t seed, const char *data, int len)
{
	const uint32_t c1 = 0xcc9e2d51;
	const uint32_t c2 = 0x1b873593;
	const uint32_t r1 = 15;
	const uint32_t r2 = 13;
	const uint32_t m = 5;
	const uint32_t n = 0xe6546b64;
	int i;
	uint32_t k1 = 0;
	const char *tail;

	int len4 = len / sizeof(uint32_t);

	uint32_t k;
	for (i = 0; i < len4; i++) {	
		uint32_t byte1 = (uint32_t)data[4*i];
		uint32_t byte2 = ((uint32_t)data[4*i + 1]) << 8;
		uint32_t byte3 = ((uint32_t)data[4*i + 2]) << 16;
		uint32_t byte4 = ((uint32_t)data[4*i + 3]) << 24;
		k = byte1 | byte2 | byte3 | byte4;
		k *= c1;
		k = rotate_right(k, r1);
		k *= c2;

		seed ^= k;
		seed = rotate_right(seed, r2) * m + n;
	}

	tail = (data + len4 * sizeof(uint32_t));

	switch (len & (sizeof(uint32_t) - 1)) {
	case 3:
		k1 ^= ((uint32_t)tail[2]) << 16;
		/*-fallthrough*/
	case 2:
		k1 ^= ((uint32_t)tail[1]) << 8;
		/*-fallthrough*/
	case 1:
		k1 ^= ((uint32_t)tail[0]) << 0;
		k1 *= c1;
		k1 = rotate_right(k1, r1);
		k1 *= c2;
		seed ^= k1;
		break;
	}

	seed ^= (uint32_t)len;
	seed ^= (seed >> 16);
	seed *= 0x85ebca6b;
	seed ^= (seed >> 13);
	seed *= 0xc2b2ae35;
	seed ^= (seed >> 16);

	return seed;
}

static inline unsigned char get_bitmask(uint32_t pos)
{
	return ((unsigned char)1) << (pos & (BITS_PER_WORD - 1));
}

void load_bloom_filters(void)
{
	init_bloom_filter_slab(&bloom_filters);
}

void fill_bloom_key(const char *data,
					int len,
					struct bloom_key *key,
					struct bloom_filter_settings *settings)
{
	int i;
	const uint32_t seed0 = 0x293ae76f;
	const uint32_t seed1 = 0x7e646e2c;
	const uint32_t hash0 = seed_murmur3(seed0, data, len);
	const uint32_t hash1 = seed_murmur3(seed1, data, len);

	key->hashes = (uint32_t *)xcalloc(settings->num_hashes, sizeof(uint32_t));
	for (i = 0; i < settings->num_hashes; i++)
		key->hashes[i] = hash0 + i * hash1;
}

void add_key_to_filter(struct bloom_key *key,
					   struct bloom_filter *filter,
					   struct bloom_filter_settings *settings)
{
	int i;
	uint64_t mod = filter->len * BITS_PER_WORD;

	for (i = 0; i < settings->num_hashes; i++) {
		uint64_t hash_mod = key->hashes[i] % mod;
		uint64_t block_pos = hash_mod / BITS_PER_WORD;

		filter->data[block_pos] |= get_bitmask(hash_mod);
	}
}

static int load_bloom_filter_from_graph(struct commit_graph *g,
				   struct bloom_filter *filter,
				   struct commit *c)
{
	uint32_t lex_pos, start_index, end_index;

	while (c->graph_pos < g->num_commits_in_base)
		g = g->base_graph;

	/* The commit graph commit 'c' lives in doesn't carry bloom filters. */
	if (!g->chunk_bloom_indexes)
		return 0;

	lex_pos = c->graph_pos - g->num_commits_in_base;

	end_index = get_be32(g->chunk_bloom_indexes + 4 * lex_pos);

	if (lex_pos)
		start_index = get_be32(g->chunk_bloom_indexes + 4 * (lex_pos - 1));
	else
		start_index = 0;

	filter->len = end_index - start_index;
	filter->data = (unsigned char *)(g->chunk_bloom_data +
					sizeof(unsigned char) * start_index +
					BLOOMDATA_CHUNK_HEADER_SIZE);

	return 1;
}

struct bloom_filter *get_bloom_filter(struct repository *r,
				      struct commit *c,
				      int compute_if_not_present)
{
	struct bloom_filter *filter;
	struct bloom_filter_settings settings = DEFAULT_BLOOM_FILTER_SETTINGS;
	int i;
	struct diff_options diffopt;
	int max_changes = 512;

	if (!bloom_filters.slab_size)
		return NULL;

	filter = bloom_filter_slab_at(&bloom_filters, c);

	if (!filter->data) {
		load_commit_graph_info(r, c);
		if (c->graph_pos != COMMIT_NOT_FROM_GRAPH &&
			r->objects->commit_graph->chunk_bloom_indexes) {
			if (load_bloom_filter_from_graph(r->objects->commit_graph, filter, c))
				return filter;
			else
				return NULL;
		}
	}

	if (filter->data || !compute_if_not_present)
		return filter;

	repo_diff_setup(r, &diffopt);
	diffopt.flags.recursive = 1;
	diffopt.max_changes = max_changes;
	diff_setup_done(&diffopt);

	if (c->parents)
		diff_tree_oid(&c->parents->item->object.oid, &c->object.oid, "", &diffopt);
	else
		diff_tree_oid(NULL, &c->object.oid, "", &diffopt);
	diffcore_std(&diffopt);

	if (diff_queued_diff.nr <= max_changes) {
		struct hashmap pathmap;
		struct pathmap_hash_entry* e;
		struct hashmap_iter iter;
		hashmap_init(&pathmap, NULL, NULL, 0);

		for (i = 0; i < diff_queued_diff.nr; i++) {
			const char* path = diff_queued_diff.queue[i]->two->path;
			const char* p = path;

			/*
			* Add each leading directory of the changed file, i.e. for
			* 'dir/subdir/file' add 'dir' and 'dir/subdir' as well, so
			* the Bloom filter could be used to speed up commands like
			* 'git log dir/subdir', too.
			*
			* Note that directories are added without the trailing '/'.
			*/
			do {
				char* last_slash = strrchr(p, '/');

				FLEX_ALLOC_STR(e, path, path);
				hashmap_entry_init(&e->entry, strhash(p));
				hashmap_add(&pathmap, &e->entry);

				if (!last_slash)
					last_slash = (char*)p;
				*last_slash = '\0';

			} while (*p);

			diff_free_filepair(diff_queued_diff.queue[i]);
		}

		filter->len = (hashmap_get_size(&pathmap) * settings.bits_per_entry + BITS_PER_WORD - 1) / BITS_PER_WORD;
		filter->data = xcalloc(filter->len, sizeof(unsigned char));

		hashmap_for_each_entry(&pathmap, &iter, e, entry) {
			struct bloom_key key;
			fill_bloom_key(e->path, strlen(e->path), &key, &settings);
			add_key_to_filter(&key, filter, &settings);
		}

		hashmap_free_entries(&pathmap, struct pathmap_hash_entry, entry);
	} else {
		for (i = 0; i < diff_queued_diff.nr; i++)
			diff_free_filepair(diff_queued_diff.queue[i]);
		filter->data = NULL;
		filter->len = 0;
	}

	free(diff_queued_diff.queue);
	DIFF_QUEUE_CLEAR(&diff_queued_diff);

	return filter;
}

int bloom_filter_contains(struct bloom_filter *filter,
			  struct bloom_key *key,
			  struct bloom_filter_settings *settings)
{
	int i;
	uint64_t mod = filter->len * BITS_PER_WORD;

	if (!mod)
		return -1;

	for (i = 0; i < settings->num_hashes; i++) {
		uint64_t hash_mod = key->hashes[i] % mod;
		uint64_t block_pos = hash_mod / BITS_PER_WORD;
		if (!(filter->data[block_pos] & get_bitmask(hash_mod)))
			return 0;
	}

	return 1;
}
debug log:

solving 6d5d6bb2ef ...
found 6d5d6bb2ef in https://public-inbox.org/git/ba856e20-0a3c-e2d2-6744-b9abfacdc465@gmail.com/
found 90d84dc713 in https://public-inbox.org/git/b20c8d2b2096bf10fe1a5f37a5181c57873a9676.1580943390.git.gitgitgadget@gmail.com/
found 818382c03b in https://public-inbox.org/git/a698c04a78cf2988fb822e0aa532989f925e0a9e.1580943390.git.gitgitgadget@gmail.com/
found 6082193a75 in https://public-inbox.org/git/02b16d94227470059dcee2781e29ae7ae010f602.1580943390.git.gitgitgadget@gmail.com/

applying [1/4] https://public-inbox.org/git/02b16d94227470059dcee2781e29ae7ae010f602.1580943390.git.gitgitgadget@gmail.com/
diff --git a/bloom.c b/bloom.c
new file mode 100644
index 0000000000..6082193a75


applying [2/4] https://public-inbox.org/git/a698c04a78cf2988fb822e0aa532989f925e0a9e.1580943390.git.gitgitgadget@gmail.com/
diff --git a/bloom.c b/bloom.c
index 6082193a75..818382c03b 100644


applying [3/4] https://public-inbox.org/git/b20c8d2b2096bf10fe1a5f37a5181c57873a9676.1580943390.git.gitgitgadget@gmail.com/
diff --git a/bloom.c b/bloom.c
index 818382c03b..90d84dc713 100644


applying [4/4] https://public-inbox.org/git/ba856e20-0a3c-e2d2-6744-b9abfacdc465@gmail.com/
diff --git a/bloom.c b/bloom.c
index 90d84dc713..6d5d6bb2ef 100644

Checking patch bloom.c...
Applied patch bloom.c cleanly.
Checking patch bloom.c...
Applied patch bloom.c cleanly.
Checking patch bloom.c...
Applied patch bloom.c cleanly.
1:352: trailing whitespace.
	for (i = 0; i < len4; i++) {	
Checking patch bloom.c...
Applied patch bloom.c cleanly.
warning: 1 line adds whitespace errors.

index at:
100644 6d5d6bb2efbbb8c149f20a9efbbeee461edffb79	bloom.c

git@vger.kernel.org list mirror (unofficial, one of many)

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://public-inbox.org/git
	git clone --mirror http://ou63pmih66umazou.onion/git
	git clone --mirror http://czquwvybam4bgbro.onion/git
	git clone --mirror http://hjrcffqmbrq6wope.onion/git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V1 git git/ https://public-inbox.org/git \
		git@vger.kernel.org
	public-inbox-index git

Example config snippet for mirrors.
Newsgroups are available over NNTP:
	nntp://news.public-inbox.org/inbox.comp.version-control.git
	nntp://ou63pmih66umazou.onion/inbox.comp.version-control.git
	nntp://czquwvybam4bgbro.onion/inbox.comp.version-control.git
	nntp://hjrcffqmbrq6wope.onion/inbox.comp.version-control.git
	nntp://news.gmane.io/gmane.comp.version-control.git
 note: .onion URLs require Tor: https://www.torproject.org/

code repositories for the project(s) associated with this inbox:

	https://80x24.org/mirrors/git.git

AGPL code for this site: git clone https://public-inbox.org/public-inbox.git