git/pack-objects.c

218 строки
4.8 KiB
C

#include "cache.h"
#include "object.h"
#include "pack.h"
#include "pack-objects.h"
#include "packfile.h"
#include "config.h"
static uint32_t locate_object_entry_hash(struct packing_data *pdata,
const unsigned char *sha1,
int *found)
{
uint32_t i, mask = (pdata->index_size - 1);
i = sha1hash(sha1) & mask;
while (pdata->index[i] > 0) {
uint32_t pos = pdata->index[i] - 1;
if (hasheq(sha1, pdata->objects[pos].idx.oid.hash)) {
*found = 1;
return i;
}
i = (i + 1) & mask;
}
*found = 0;
return i;
}
static inline uint32_t closest_pow2(uint32_t v)
{
v = v - 1;
v |= v >> 1;
v |= v >> 2;
v |= v >> 4;
v |= v >> 8;
v |= v >> 16;
return v + 1;
}
static void rehash_objects(struct packing_data *pdata)
{
uint32_t i;
struct object_entry *entry;
pdata->index_size = closest_pow2(pdata->nr_objects * 3);
if (pdata->index_size < 1024)
pdata->index_size = 1024;
free(pdata->index);
pdata->index = xcalloc(pdata->index_size, sizeof(*pdata->index));
entry = pdata->objects;
for (i = 0; i < pdata->nr_objects; i++) {
int found;
uint32_t ix = locate_object_entry_hash(pdata,
entry->idx.oid.hash,
&found);
if (found)
BUG("Duplicate object in hash");
pdata->index[ix] = i + 1;
entry++;
}
}
struct object_entry *packlist_find(struct packing_data *pdata,
const unsigned char *sha1,
uint32_t *index_pos)
{
uint32_t i;
int found;
if (!pdata->index_size)
return NULL;
i = locate_object_entry_hash(pdata, sha1, &found);
if (index_pos)
*index_pos = i;
if (!found)
return NULL;
return &pdata->objects[pdata->index[i] - 1];
}
static void prepare_in_pack_by_idx(struct packing_data *pdata)
{
struct packed_git **mapping, *p;
int cnt = 0, nr = 1U << OE_IN_PACK_BITS;
ALLOC_ARRAY(mapping, nr);
/*
* oe_in_pack() on an all-zero'd object_entry
* (i.e. in_pack_idx also zero) should return NULL.
*/
mapping[cnt++] = NULL;
for (p = get_all_packs(the_repository); p; p = p->next, cnt++) {
if (cnt == nr) {
free(mapping);
return;
}
p->index = cnt;
mapping[cnt] = p;
}
pdata->in_pack_by_idx = mapping;
}
/*
* A new pack appears after prepare_in_pack_by_idx() has been
* run. This is likely a race.
*
* We could map this new pack to in_pack_by_idx[] array, but then we
* have to deal with full array anyway. And since it's hard to test
* this fall back code, just stay simple and fall back to using
* in_pack[] array.
*/
void oe_map_new_pack(struct packing_data *pack,
struct packed_git *p)
{
uint32_t i;
REALLOC_ARRAY(pack->in_pack, pack->nr_alloc);
for (i = 0; i < pack->nr_objects; i++)
pack->in_pack[i] = oe_in_pack(pack, pack->objects + i);
FREE_AND_NULL(pack->in_pack_by_idx);
}
/* assume pdata is already zero'd by caller */
void prepare_packing_data(struct packing_data *pdata)
{
if (git_env_bool("GIT_TEST_FULL_IN_PACK_ARRAY", 0)) {
/*
* do not initialize in_pack_by_idx[] to force the
* slow path in oe_in_pack()
*/
} else {
prepare_in_pack_by_idx(pdata);
}
pdata->oe_size_limit = git_env_ulong("GIT_TEST_OE_SIZE",
1U << OE_SIZE_BITS);
pdata->oe_delta_size_limit = git_env_ulong("GIT_TEST_OE_DELTA_SIZE",
1UL << OE_DELTA_SIZE_BITS);
#ifndef NO_PTHREADS
pthread_mutex_init(&pdata->lock, NULL);
#endif
}
struct object_entry *packlist_alloc(struct packing_data *pdata,
const unsigned char *sha1,
uint32_t index_pos)
{
struct object_entry *new_entry;
if (pdata->nr_objects >= pdata->nr_alloc) {
pdata->nr_alloc = (pdata->nr_alloc + 1024) * 3 / 2;
REALLOC_ARRAY(pdata->objects, pdata->nr_alloc);
if (!pdata->in_pack_by_idx)
REALLOC_ARRAY(pdata->in_pack, pdata->nr_alloc);
if (pdata->delta_size)
REALLOC_ARRAY(pdata->delta_size, pdata->nr_alloc);
if (pdata->tree_depth)
REALLOC_ARRAY(pdata->tree_depth, pdata->nr_alloc);
if (pdata->layer)
REALLOC_ARRAY(pdata->layer, pdata->nr_alloc);
}
new_entry = pdata->objects + pdata->nr_objects++;
memset(new_entry, 0, sizeof(*new_entry));
hashcpy(new_entry->idx.oid.hash, sha1);
if (pdata->index_size * 3 <= pdata->nr_objects * 4)
rehash_objects(pdata);
else
pdata->index[index_pos] = pdata->nr_objects;
if (pdata->in_pack)
pdata->in_pack[pdata->nr_objects - 1] = NULL;
if (pdata->tree_depth)
pdata->tree_depth[pdata->nr_objects - 1] = 0;
if (pdata->layer)
pdata->layer[pdata->nr_objects - 1] = 0;
return new_entry;
}
void oe_set_delta_ext(struct packing_data *pdata,
struct object_entry *delta,
const unsigned char *sha1)
{
struct object_entry *base;
ALLOC_GROW(pdata->ext_bases, pdata->nr_ext + 1, pdata->alloc_ext);
base = &pdata->ext_bases[pdata->nr_ext++];
memset(base, 0, sizeof(*base));
hashcpy(base->idx.oid.hash, sha1);
/* These flags mark that we are not part of the actual pack output. */
base->preferred_base = 1;
base->filled = 1;
delta->ext_base = 1;
delta->delta_idx = base - pdata->ext_bases + 1;
}