tvl-depot/third_party/git/pack-objects.c
Vincent Ambo f4609b896f merge(3p/git): Merge git subtree at v2.29.2
This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb
2020-11-21 19:45:56 +01:00

221 lines
5 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 struct object_id *oid,
int *found)
{
uint32_t i, mask = (pdata->index_size - 1);
i = oidhash(oid) & mask;
while (pdata->index[i] > 0) {
uint32_t pos = pdata->index[i] - 1;
if (oideq(oid, &pdata->objects[pos].idx.oid)) {
*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,
&found);
if (found)
BUG("Duplicate object in hash");
pdata->index[ix] = i + 1;
entry++;
}
}
struct object_entry *packlist_find(struct packing_data *pdata,
const struct object_id *oid)
{
uint32_t i;
int found;
if (!pdata->index_size)
return NULL;
i = locate_object_entry_hash(pdata, oid, &found);
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(pdata->repo); 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)
{
uint32_t i;
if (pack->in_pack)
BUG("packing_data has already been converted to pack array");
ALLOC_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 repository *r, struct packing_data *pdata)
{
pdata->repo = r;
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);
init_recursive_mutex(&pdata->odb_lock);
}
struct object_entry *packlist_alloc(struct packing_data *pdata,
const struct object_id *oid)
{
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));
oidcpy(&new_entry->idx.oid, oid);
if (pdata->index_size * 3 <= pdata->nr_objects * 4)
rehash_objects(pdata);
else {
int found;
uint32_t pos = locate_object_entry_hash(pdata,
&new_entry->idx.oid,
&found);
if (found)
BUG("duplicate object inserted into hash");
pdata->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 struct object_id *oid)
{
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));
oidcpy(&base->idx.oid, oid);
/* 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;
}