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Commit | Line | Data |
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f52207a4 GS |
1 | #include "git-compat-util.h" |
2 | #include "bloom.h" | |
ed591feb GS |
3 | #include "diff.h" |
4 | #include "diffcore.h" | |
ed591feb | 5 | #include "hashmap.h" |
1217c03e GS |
6 | #include "commit-graph.h" |
7 | #include "commit.h" | |
d4a4f929 | 8 | #include "commit-slab.h" |
ed591feb GS |
9 | |
10 | define_commit_slab(bloom_filter_slab, struct bloom_filter); | |
11 | ||
066b70ae | 12 | static struct bloom_filter_slab bloom_filters; |
ed591feb GS |
13 | |
14 | struct pathmap_hash_entry { | |
15 | struct hashmap_entry entry; | |
16 | const char path[FLEX_ARRAY]; | |
17 | }; | |
f52207a4 GS |
18 | |
19 | static uint32_t rotate_left(uint32_t value, int32_t count) | |
20 | { | |
21 | uint32_t mask = 8 * sizeof(uint32_t) - 1; | |
22 | count &= mask; | |
23 | return ((value << count) | (value >> ((-count) & mask))); | |
24 | } | |
25 | ||
f1294eaf GS |
26 | static inline unsigned char get_bitmask(uint32_t pos) |
27 | { | |
28 | return ((unsigned char)1) << (pos & (BITS_PER_WORD - 1)); | |
29 | } | |
30 | ||
920f400e JK |
31 | static int check_bloom_offset(struct commit_graph *g, uint32_t pos, |
32 | uint32_t offset) | |
33 | { | |
34 | /* | |
35 | * Note that we allow offsets equal to the data size, which would set | |
36 | * our pointers at one past the end of the chunk memory. This is | |
37 | * necessary because the on-disk index points to the end of the | |
38 | * entries (so we can compute size by comparing adjacent ones). And | |
39 | * naturally the final entry's end is one-past-the-end of the chunk. | |
40 | */ | |
41 | if (offset <= g->chunk_bloom_data_size - BLOOMDATA_CHUNK_HEADER_SIZE) | |
42 | return 0; | |
43 | ||
44 | warning("ignoring out-of-range offset (%"PRIuMAX") for changed-path" | |
45 | " filter at pos %"PRIuMAX" of %s (chunk size: %"PRIuMAX")", | |
46 | (uintmax_t)offset, (uintmax_t)pos, | |
47 | g->filename, (uintmax_t)g->chunk_bloom_data_size); | |
48 | return -1; | |
49 | } | |
50 | ||
1217c03e | 51 | static int load_bloom_filter_from_graph(struct commit_graph *g, |
eb591e42 | 52 | struct bloom_filter *filter, |
9550f6c1 | 53 | uint32_t graph_pos) |
1217c03e GS |
54 | { |
55 | uint32_t lex_pos, start_index, end_index; | |
56 | ||
c752ad09 | 57 | while (graph_pos < g->num_commits_in_base) |
1217c03e GS |
58 | g = g->base_graph; |
59 | ||
4f364405 | 60 | /* The commit graph commit 'c' lives in doesn't carry Bloom filters. */ |
1217c03e GS |
61 | if (!g->chunk_bloom_indexes) |
62 | return 0; | |
63 | ||
c752ad09 | 64 | lex_pos = graph_pos - g->num_commits_in_base; |
1217c03e GS |
65 | |
66 | end_index = get_be32(g->chunk_bloom_indexes + 4 * lex_pos); | |
67 | ||
68 | if (lex_pos > 0) | |
69 | start_index = get_be32(g->chunk_bloom_indexes + 4 * (lex_pos - 1)); | |
70 | else | |
71 | start_index = 0; | |
72 | ||
920f400e JK |
73 | if (check_bloom_offset(g, lex_pos, end_index) < 0 || |
74 | check_bloom_offset(g, lex_pos - 1, start_index) < 0) | |
75 | return 0; | |
76 | ||
12192a9d JK |
77 | if (end_index < start_index) { |
78 | warning("ignoring decreasing changed-path index offsets" | |
79 | " (%"PRIuMAX" > %"PRIuMAX") for positions" | |
80 | " %"PRIuMAX" and %"PRIuMAX" of %s", | |
81 | (uintmax_t)start_index, (uintmax_t)end_index, | |
82 | (uintmax_t)(lex_pos-1), (uintmax_t)lex_pos, | |
83 | g->filename); | |
84 | return 0; | |
85 | } | |
86 | ||
1217c03e GS |
87 | filter->len = end_index - start_index; |
88 | filter->data = (unsigned char *)(g->chunk_bloom_data + | |
89 | sizeof(unsigned char) * start_index + | |
90 | BLOOMDATA_CHUNK_HEADER_SIZE); | |
91 | ||
92 | return 1; | |
93 | } | |
94 | ||
f52207a4 GS |
95 | /* |
96 | * Calculate the murmur3 32-bit hash value for the given data | |
97 | * using the given seed. | |
98 | * Produces a uniformly distributed hash value. | |
99 | * Not considered to be cryptographically secure. | |
100 | * Implemented as described in https://en.wikipedia.org/wiki/MurmurHash#Algorithm | |
101 | */ | |
102 | uint32_t murmur3_seeded(uint32_t seed, const char *data, size_t len) | |
103 | { | |
104 | const uint32_t c1 = 0xcc9e2d51; | |
105 | const uint32_t c2 = 0x1b873593; | |
106 | const uint32_t r1 = 15; | |
107 | const uint32_t r2 = 13; | |
108 | const uint32_t m = 5; | |
109 | const uint32_t n = 0xe6546b64; | |
110 | int i; | |
111 | uint32_t k1 = 0; | |
112 | const char *tail; | |
113 | ||
114 | int len4 = len / sizeof(uint32_t); | |
115 | ||
116 | uint32_t k; | |
117 | for (i = 0; i < len4; i++) { | |
118 | uint32_t byte1 = (uint32_t)data[4*i]; | |
119 | uint32_t byte2 = ((uint32_t)data[4*i + 1]) << 8; | |
120 | uint32_t byte3 = ((uint32_t)data[4*i + 2]) << 16; | |
121 | uint32_t byte4 = ((uint32_t)data[4*i + 3]) << 24; | |
122 | k = byte1 | byte2 | byte3 | byte4; | |
123 | k *= c1; | |
124 | k = rotate_left(k, r1); | |
125 | k *= c2; | |
126 | ||
127 | seed ^= k; | |
128 | seed = rotate_left(seed, r2) * m + n; | |
129 | } | |
130 | ||
131 | tail = (data + len4 * sizeof(uint32_t)); | |
132 | ||
133 | switch (len & (sizeof(uint32_t) - 1)) { | |
134 | case 3: | |
135 | k1 ^= ((uint32_t)tail[2]) << 16; | |
136 | /*-fallthrough*/ | |
137 | case 2: | |
138 | k1 ^= ((uint32_t)tail[1]) << 8; | |
139 | /*-fallthrough*/ | |
140 | case 1: | |
141 | k1 ^= ((uint32_t)tail[0]) << 0; | |
142 | k1 *= c1; | |
143 | k1 = rotate_left(k1, r1); | |
144 | k1 *= c2; | |
145 | seed ^= k1; | |
146 | break; | |
147 | } | |
148 | ||
149 | seed ^= (uint32_t)len; | |
150 | seed ^= (seed >> 16); | |
151 | seed *= 0x85ebca6b; | |
152 | seed ^= (seed >> 13); | |
153 | seed *= 0xc2b2ae35; | |
154 | seed ^= (seed >> 16); | |
155 | ||
156 | return seed; | |
f1294eaf GS |
157 | } |
158 | ||
159 | void fill_bloom_key(const char *data, | |
eb591e42 DS |
160 | size_t len, |
161 | struct bloom_key *key, | |
162 | const struct bloom_filter_settings *settings) | |
f1294eaf GS |
163 | { |
164 | int i; | |
165 | const uint32_t seed0 = 0x293ae76f; | |
166 | const uint32_t seed1 = 0x7e646e2c; | |
167 | const uint32_t hash0 = murmur3_seeded(seed0, data, len); | |
168 | const uint32_t hash1 = murmur3_seeded(seed1, data, len); | |
169 | ||
170 | key->hashes = (uint32_t *)xcalloc(settings->num_hashes, sizeof(uint32_t)); | |
171 | for (i = 0; i < settings->num_hashes; i++) | |
172 | key->hashes[i] = hash0 + i * hash1; | |
173 | } | |
174 | ||
f32dde8c DS |
175 | void clear_bloom_key(struct bloom_key *key) |
176 | { | |
177 | FREE_AND_NULL(key->hashes); | |
178 | } | |
179 | ||
f1294eaf | 180 | void add_key_to_filter(const struct bloom_key *key, |
eb591e42 DS |
181 | struct bloom_filter *filter, |
182 | const struct bloom_filter_settings *settings) | |
f1294eaf GS |
183 | { |
184 | int i; | |
185 | uint64_t mod = filter->len * BITS_PER_WORD; | |
186 | ||
187 | for (i = 0; i < settings->num_hashes; i++) { | |
188 | uint64_t hash_mod = key->hashes[i] % mod; | |
189 | uint64_t block_pos = hash_mod / BITS_PER_WORD; | |
190 | ||
191 | filter->data[block_pos] |= get_bitmask(hash_mod); | |
192 | } | |
193 | } | |
ed591feb GS |
194 | |
195 | void init_bloom_filters(void) | |
196 | { | |
197 | init_bloom_filter_slab(&bloom_filters); | |
198 | } | |
199 | ||
5cf88fd8 | 200 | static int pathmap_cmp(const void *hashmap_cmp_fn_data UNUSED, |
65c1a28b DS |
201 | const struct hashmap_entry *eptr, |
202 | const struct hashmap_entry *entry_or_key, | |
5cf88fd8 | 203 | const void *keydata UNUSED) |
65c1a28b DS |
204 | { |
205 | const struct pathmap_hash_entry *e1, *e2; | |
206 | ||
207 | e1 = container_of(eptr, const struct pathmap_hash_entry, entry); | |
208 | e2 = container_of(entry_or_key, const struct pathmap_hash_entry, entry); | |
209 | ||
210 | return strcmp(e1->path, e2->path); | |
211 | } | |
212 | ||
59f0d507 TB |
213 | static void init_truncated_large_filter(struct bloom_filter *filter) |
214 | { | |
215 | filter->data = xmalloc(1); | |
216 | filter->data[0] = 0xFF; | |
217 | filter->len = 1; | |
218 | } | |
219 | ||
312cff52 TB |
220 | struct bloom_filter *get_or_compute_bloom_filter(struct repository *r, |
221 | struct commit *c, | |
222 | int compute_if_not_present, | |
9a7a9ed1 | 223 | const struct bloom_filter_settings *settings, |
312cff52 | 224 | enum bloom_filter_computed *computed) |
ed591feb GS |
225 | { |
226 | struct bloom_filter *filter; | |
ed591feb GS |
227 | int i; |
228 | struct diff_options diffopt; | |
229 | ||
312cff52 TB |
230 | if (computed) |
231 | *computed = BLOOM_NOT_COMPUTED; | |
232 | ||
94919742 | 233 | if (!bloom_filters.slab_size) |
ed591feb GS |
234 | return NULL; |
235 | ||
236 | filter = bloom_filter_slab_at(&bloom_filters, c); | |
237 | ||
1217c03e | 238 | if (!filter->data) { |
9550f6c1 TB |
239 | uint32_t graph_pos; |
240 | if (repo_find_commit_pos_in_graph(r, c, &graph_pos)) | |
241 | load_bloom_filter_from_graph(r->objects->commit_graph, | |
242 | filter, graph_pos); | |
1217c03e GS |
243 | } |
244 | ||
809e0327 | 245 | if (filter->data && filter->len) |
1217c03e | 246 | return filter; |
94919742 DS |
247 | if (!compute_if_not_present) |
248 | return NULL; | |
1217c03e | 249 | |
ed591feb GS |
250 | repo_diff_setup(r, &diffopt); |
251 | diffopt.flags.recursive = 1; | |
caf388ca | 252 | diffopt.detect_rename = 0; |
9a7a9ed1 | 253 | diffopt.max_changes = settings->max_changed_paths; |
ed591feb GS |
254 | diff_setup_done(&diffopt); |
255 | ||
891c17c9 DS |
256 | /* ensure commit is parsed so we have parent information */ |
257 | repo_parse_commit(r, c); | |
258 | ||
ed591feb GS |
259 | if (c->parents) |
260 | diff_tree_oid(&c->parents->item->object.oid, &c->object.oid, "", &diffopt); | |
261 | else | |
262 | diff_tree_oid(NULL, &c->object.oid, "", &diffopt); | |
263 | diffcore_std(&diffopt); | |
264 | ||
b16a8277 | 265 | if (diff_queued_diff.nr <= settings->max_changed_paths) { |
b19315d8 | 266 | struct hashmap pathmap = HASHMAP_INIT(pathmap_cmp, NULL); |
ed591feb GS |
267 | struct pathmap_hash_entry *e; |
268 | struct hashmap_iter iter; | |
ed591feb GS |
269 | |
270 | for (i = 0; i < diff_queued_diff.nr; i++) { | |
271 | const char *path = diff_queued_diff.queue[i]->two->path; | |
272 | ||
273 | /* | |
65c1a28b DS |
274 | * Add each leading directory of the changed file, i.e. for |
275 | * 'dir/subdir/file' add 'dir' and 'dir/subdir' as well, so | |
276 | * the Bloom filter could be used to speed up commands like | |
277 | * 'git log dir/subdir', too. | |
278 | * | |
279 | * Note that directories are added without the trailing '/'. | |
280 | */ | |
ed591feb GS |
281 | do { |
282 | char *last_slash = strrchr(path, '/'); | |
283 | ||
284 | FLEX_ALLOC_STR(e, path, path); | |
285 | hashmap_entry_init(&e->entry, strhash(path)); | |
65c1a28b DS |
286 | |
287 | if (!hashmap_get(&pathmap, &e->entry, NULL)) | |
288 | hashmap_add(&pathmap, &e->entry); | |
289 | else | |
290 | free(e); | |
ed591feb GS |
291 | |
292 | if (!last_slash) | |
293 | last_slash = (char*)path; | |
294 | *last_slash = '\0'; | |
295 | ||
296 | } while (*path); | |
297 | ||
298 | diff_free_filepair(diff_queued_diff.queue[i]); | |
299 | } | |
300 | ||
b16a8277 | 301 | if (hashmap_get_size(&pathmap) > settings->max_changed_paths) { |
59f0d507 | 302 | init_truncated_large_filter(filter); |
b16a8277 DS |
303 | if (computed) |
304 | *computed |= BLOOM_TRUNC_LARGE; | |
305 | goto cleanup; | |
306 | } | |
307 | ||
9a7a9ed1 | 308 | filter->len = (hashmap_get_size(&pathmap) * settings->bits_per_entry + BITS_PER_WORD - 1) / BITS_PER_WORD; |
59f0d507 TB |
309 | if (!filter->len) { |
310 | if (computed) | |
311 | *computed |= BLOOM_TRUNC_EMPTY; | |
312 | filter->len = 1; | |
313 | } | |
ca56dadb | 314 | CALLOC_ARRAY(filter->data, filter->len); |
ed591feb GS |
315 | |
316 | hashmap_for_each_entry(&pathmap, &iter, e, entry) { | |
317 | struct bloom_key key; | |
9a7a9ed1 TB |
318 | fill_bloom_key(e->path, strlen(e->path), &key, settings); |
319 | add_key_to_filter(&key, filter, settings); | |
b180c681 | 320 | clear_bloom_key(&key); |
ed591feb GS |
321 | } |
322 | ||
b16a8277 | 323 | cleanup: |
6da1a258 | 324 | hashmap_clear_and_free(&pathmap, struct pathmap_hash_entry, entry); |
ed591feb GS |
325 | } else { |
326 | for (i = 0; i < diff_queued_diff.nr; i++) | |
327 | diff_free_filepair(diff_queued_diff.queue[i]); | |
59f0d507 | 328 | init_truncated_large_filter(filter); |
312cff52 TB |
329 | |
330 | if (computed) | |
331 | *computed |= BLOOM_TRUNC_LARGE; | |
ed591feb GS |
332 | } |
333 | ||
312cff52 TB |
334 | if (computed) |
335 | *computed |= BLOOM_COMPUTED; | |
336 | ||
ed591feb GS |
337 | free(diff_queued_diff.queue); |
338 | DIFF_QUEUE_CLEAR(&diff_queued_diff); | |
339 | ||
340 | return filter; | |
341 | } | |
a56b9464 GS |
342 | |
343 | int bloom_filter_contains(const struct bloom_filter *filter, | |
344 | const struct bloom_key *key, | |
345 | const struct bloom_filter_settings *settings) | |
346 | { | |
347 | int i; | |
348 | uint64_t mod = filter->len * BITS_PER_WORD; | |
349 | ||
350 | if (!mod) | |
351 | return -1; | |
352 | ||
353 | for (i = 0; i < settings->num_hashes; i++) { | |
354 | uint64_t hash_mod = key->hashes[i] % mod; | |
355 | uint64_t block_pos = hash_mod / BITS_PER_WORD; | |
356 | if (!(filter->data[block_pos] & get_bitmask(hash_mod))) | |
357 | return 0; | |
358 | } | |
359 | ||
360 | return 1; | |
066b70ae | 361 | } |