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#define DISABLE_SIGN_COMPARE_WARNINGS

#include "git-compat-util.h"

#include "bloom.h"

#include "diff.h"

#include "diffcore.h"

#include "hashmap.h"

#include "commit-graph.h"

#include "commit.h"

#include "commit-slab.h"

#include "tree.h"

#include "tree-walk.h"

#include "config.h"

#include "repository.h"

define_commit_slab(bloom_filter_slab, struct bloom_filter);

static struct bloom_filter_slab bloom_filters;

struct pathmap_hash_entry {

struct hashmap_entry entry;

const char path[FLEX_ARRAY];

};

static uint32_t rotate_left(uint32_t value, int32_t count)

{

uint32_t mask = 8 * sizeof(uint32_t) - 1;

count &= mask;

return ((value << count) | (value >> ((-count) & mask)));

}

static inline unsigned char get_bitmask(uint32_t pos)

{

return ((unsigned char)1) << (pos & (BITS_PER_WORD - 1));

}

static int check_bloom_offset(struct commit_graph *g, uint32_t pos,

uint32_t offset)

{

* Note that we allow offsets equal to the data size, which would set

* our pointers at one past the end of the chunk memory. This is

* necessary because the on-disk index points to the end of the

* entries (so we can compute size by comparing adjacent ones). And

* naturally the final entry's end is one-past-the-end of the chunk.

if (offset <= g->chunk_bloom_data_size - BLOOMDATA_CHUNK_HEADER_SIZE)

return 0;

warning("ignoring out-of-range offset (%"PRIuMAX") for changed-path"

" filter at pos %"PRIuMAX" of %s (chunk size: %"PRIuMAX")",

(uintmax_t)offset, (uintmax_t)pos,

g->filename, (uintmax_t)g->chunk_bloom_data_size);

return -1;

}

int load_bloom_filter_from_graph(struct commit_graph *g,

struct bloom_filter *filter,

uint32_t graph_pos)

{

uint32_t lex_pos, start_index, end_index;

while (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 = graph_pos - g->num_commits_in_base;

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

if (lex_pos > 0)

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

else

start_index = 0;

if (check_bloom_offset(g, lex_pos, end_index) < 0 ||

check_bloom_offset(g, lex_pos - 1, start_index) < 0)

return 0;

if (end_index < start_index) {

warning("ignoring decreasing changed-path index offsets"

" (%"PRIuMAX" > %"PRIuMAX") for positions"

" %"PRIuMAX" and %"PRIuMAX" of %s",

(uintmax_t)start_index, (uintmax_t)end_index,

(uintmax_t)(lex_pos-1), (uintmax_t)lex_pos,

g->filename);

return 0;

}

filter->len = end_index - start_index;

filter->data = (unsigned char *)(g->chunk_bloom_data +

sizeof(unsigned char) * start_index +

BLOOMDATA_CHUNK_HEADER_SIZE);

filter->version = g->bloom_filter_settings->hash_version;

filter->to_free = NULL;

return 1;

}

* Calculate the murmur3 32-bit 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 murmur3_seeded_v2(uint32_t seed, const char *data, size_t 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)(unsigned char)data[4*i];

uint32_t byte2 = ((uint32_t)(unsigned char)data[4*i + 1]) << 8;

uint32_t byte3 = ((uint32_t)(unsigned char)data[4*i + 2]) << 16;

uint32_t byte4 = ((uint32_t)(unsigned char)data[4*i + 3]) << 24;

k = byte1 | byte2 | byte3 | byte4;

k *= c1;

k = rotate_left(k, r1);

k *= c2;

seed ^= k;

seed = rotate_left(seed, r2) * m + n;

}

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

switch (len & (sizeof(uint32_t) - 1)) {

case 3:

k1 ^= ((uint32_t)(unsigned char)tail[2]) << 16;

/*-fallthrough*/

case 2:

k1 ^= ((uint32_t)(unsigned char)tail[1]) << 8;

/*-fallthrough*/

case 1:

k1 ^= ((uint32_t)(unsigned char)tail[0]) << 0;

k1 *= c1;

k1 = rotate_left(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 uint32_t murmur3_seeded_v1(uint32_t seed, const char *data, size_t 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_left(k, r1);

k *= c2;

seed ^= k;

seed = rotate_left(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_left(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;

}

void bloom_key_fill(struct bloom_key *key, const char *data, size_t len,

const struct bloom_filter_settings *settings)

{

int i;

const uint32_t seed0 = 0x293ae76f;

const uint32_t seed1 = 0x7e646e2c;

uint32_t hash0, hash1;

if (settings->hash_version == 2) {

hash0 = murmur3_seeded_v2(seed0, data, len);

hash1 = murmur3_seeded_v2(seed1, data, len);

} else {

hash0 = murmur3_seeded_v1(seed0, data, len);

hash1 = murmur3_seeded_v1(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 bloom_key_clear(struct bloom_key *key)

{

FREE_AND_NULL(key->hashes);

}

void add_key_to_filter(const struct bloom_key *key,

struct bloom_filter *filter,

const struct bloom_filter_settings *settings)

{

int i;

uint64_t mod = filter->len * BITS_PER_WORD;

f 8000 or (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);

}

void init_bloom_filters(void)

{

init_bloom_filter_slab(&bloom_filters);

}

static void free_one_bloom_filter(struct bloom_filter *filter)

{

if (!filter)

return;

free(filter->to_free);

}

void deinit_bloom_filters(void)

{

deep_clear_bloom_filter_slab(&bloom_filters, free_one_bloom_filter);

}

struct bloom_keyvec *bloom_keyvec_new(const char *path, size_t len,

const struct bloom_filter_settings *settings)

{

struct bloom_keyvec *vec;

const char *p;

size_t sz;

size_t nr = 1;

p = path;

while (*p) {

* At this point, the path is normalized to use Unix-style

* path separators. This is required due to how the

* changed-path Bloom filters store the paths.

if (*p == '/')

nr++;

p++;

}

sz = sizeof(struct bloom_keyvec);

sz += nr * sizeof(struct bloom_key);

vec = (struct bloom_keyvec *)xcalloc(1, sz);

if (!vec)

return NULL;

vec->count = nr;

bloom_key_fill(&vec->key[0], path, len, settings);

nr = 1;

p = path + len - 1;

while (p > path) {

if (*p == '/') {

bloom_key_fill(&vec->key[nr++], path, p - path, settings);

}

p--;

}

assert(nr == vec->count);

return vec;

}

void bloom_keyvec_free(struct bloom_keyvec *vec)

{

if (!vec)

return;

for (size_t nr = 0; nr < vec->count; nr++)

bloom_key_clear(&vec->key[nr]);

free(vec);

}

static int pathmap_cmp(const void *hashmap_cmp_fn_data UNUSED,

const struct hashmap_entry *eptr,

const struct hashmap_entry *entry_or_key,

const void *keydata UNUSED)

{

const struct pathmap_hash_entry *e1, *e2;

e1 = container_of(eptr, const struct pathmap_hash_entry, entry);

e2 = container_of(entry_or_key, const struct pathmap_hash_entry, entry);

return strcmp(e1->path, e2->path);

}

static void init_truncated_large_filter(struct bloom_filter *filter,

int version)

{

filter->data = filter->to_free = xmalloc(1);

filter->data[0] = 0xFF;

filter->len = 1;

filter->version = version;

}

#define VISITED (1u<<21)

#define HIGH_BITS (1u<<22)

static int has_entries_with_high_bit(struct repository *r, struct tree *t)

{

if (repo_parse_tree(r, t))

return 1;

if (!(t->object.flags & VISITED)) {

struct tree_desc desc;

struct name_entry entry;

init_tree_desc(&desc, &t->object.oid, t->buffer, t->size);

while (tree_entry(&desc, &entry)) {

size_t i;

for (i = 0; i < entry.pathlen; i++) {

if (entry.path[i] & 0x80) {

t->object.flags |= HIGH_BITS;

goto done;

}

if (S_ISDIR(entry.mode)) {

struct tree *sub = lookup_tree(r, &entry.oid);

if (sub && has_entries_with_high_bit(r, sub)) {

t->object.flags |= HIGH_BITS;

goto done;

}

done:

t->object.flags |= VISITED;

}

return !!(t->object.flags & HIGH_BITS);

}

static int commit_tree_has_high_bit_paths(struct repository *r,

struct commit *c)

{

struct tree *t;

if (repo_parse_commit(r, c))

return 1;

t = repo_get_commit_tree(r, c);

if (!t)

return 1;

return has_entries_with_high_bit(r, t);

}

static struct bloom_filter *upgrade_filter(struct repository *r, struct commit *c,

struct bloom_filter *filter,

int hash_version)

{

struct commit_list *p = c->parents;

if (commit_tree_has_high_bit_paths(r, c))

return NULL;

if (p && commit_tree_has_high_bit_paths(r, p->item))

return NULL;

filter->version = hash_version;

return filter;

}

struct bloom_filter *get_bloom_filter(struct repository *r, struct commit *c)

{

struct bloom_filter *filter;

int hash_version;

filter = get_or_compute_bloom_filter(r, c, 0, NULL, NULL);

if (!filter)

return NULL;

prepare_repo_settings(r);

hash_version = r->settings.commit_graph_changed_paths_version;

if (!(hash_version == -1 || hash_version == filter->version))

return NULL; /* unusable filter */

return filter;

}

struct bloom_filter *get_or_compute_bloom_filter(struct repository *r,

struct commit *c,

int compute_if_not_present,

const struct bloom_filter_settings *settings,

enum bloom_filter_computed *computed)

{

struct bloom_filter *filter;

int i;

struct diff_options diffopt;

if (computed)

*computed = BLOOM_NOT_COMPUTED;

if (!bloom_filters.slab_size)

return NULL;

filter = bloom_filter_slab_at(&bloom_filters, c);

if (!filter->data) {

struct commit_graph *g;

uint32_t graph_pos;

g = repo_find_commit_pos_in_graph(r, c, &graph_pos);

if (g)

load_bloom_filter_from_graph(g, filter, graph_pos);

}

if (filter->data && filter->len) {

struct bloom_filter *upgrade;

if (!settings || settings->hash_version == filter->version)

return filter;

/* version mismatch, see if we can upgrade */

if (compute_if_not_present &&

BAB4 git_env_bool("GIT_TEST_UPGRADE_BLOOM_FILTERS", 1)) {

upgrade = upgrade_filter(r, c, filter,

settings->hash_version);

if (upgrade) {

if (computed)

*computed |= BLOOM_UPGRADED;

return upgrade;

}

if (!compute_if_not_present)

return NULL;

repo_diff_setup(r, &diffopt);

diffopt.flags.recursive = 1;

diffopt.detect_rename = 0;

diffopt.max_changes = settings->max_changed_paths;

diff_setup_done(&diffopt);

/* ensure commit is parsed so we have parent information */

repo_parse_commit(r, c);

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 <= settings->max_changed_paths) {

struct hashmap pathmap = HASHMAP_INIT(pathmap_cmp, NULL);

struct pathmap_hash_entry *e;

struct hashmap_iter iter;

for (i = 0; i < diff_queued_diff.nr; i++) {

const char *path = diff_queued_diff.queue[i]->two->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(path, '/');

FLEX_ALLOC_STR(e, path, path);

hashmap_entry_init(&e->entry, strhash(path));

if (!hashmap_get(&pathmap, &e->entry, NULL))

hashmap_add(&pathmap, &e->entry);

else

free(e);

if (!last_slash)

last_slash = (char*)path;

*last_slash = '\0';

} while (*path);

}

if (hashmap_get_size(&pathmap) > settings->max_changed_paths) {

init_truncated_large_filter(filter,

settings->hash_version);

if (computed)

*computed |= BLOOM_TRUNC_LARGE;

goto cleanup;

}

filter->len = (hashmap_get_size(&pathmap) * settings->bits_per_entry + BITS_PER_WORD - 1) / BITS_PER_WORD;

filter->version = settings->hash_version;

if (!filter->len) {

if (computed)

*computed |= BLOOM_TRUNC_EMPTY;

filter->len = 1;

}

CALLOC_ARRAY(filter->data, filter->len);

filter->to_free = filter->data;

hashmap_for_each_entry(&pathmap, &iter, e, entry) {

struct bloom_key key;

bloom_key_fill(&key, e->path, strlen(e->path), settings);

add_key_to_filter(&key, filter, settings);

bloom_key_clear(&key);

}

cleanup:

hashmap_clear_and_free(&pathmap, struct pathmap_hash_entry, entry);

} else {

init_truncated_large_filter(filter, settings->hash_version);

if (computed)

*computed |= BLOOM_TRUNC_LARGE;

}

if (computed)

*computed |= BLOOM_COMPUTED;

diff_queue_clear(&diff_queued_diff);

return filter;

}

int bloom_filter_contains(const struct bloom_filter *filter,

const struct bloom_key *key,

const 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;

}

int bloom_filter_contains_vec(const struct bloom_filter *filter,

const struct bloom_keyvec *vec,

const struct bloom_filter_settings *settings)

{

int ret = 1;

for (size_t nr = 0; ret > 0 && nr < vec->count; nr++)

ret = bloom_filter_contains(filter, &vec->key[nr], settings);

return ret;

}

uint32_t test_bloom_murmur3_seeded(uint32_t seed, const char *data, size_t len,

int version)

{

assert(version == 1 || version == 2);

if (version == 2)

return murmur3_seeded_v2(seed, data, len);

else

return murmur3_seeded_v1(seed, data, len);

}

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