mirror of
https://github.com/git/git.git
synced 2024-11-01 06:47:52 +01:00
2834bc27c1
The hash table that stores the packing list for a given `pack-objects` run was tightly coupled to the pack-objects code. In this commit, we refactor the hash table and the underlying storage array into a `packing_data` struct. The functionality for accessing and adding entries to the packing list is hence accessible from other parts of Git besides the `pack-objects` builtin. This refactoring is a requirement for further patches in this series that will require accessing the commit packing list from outside of `pack-objects`. The hash table implementation has been minimally altered: we now use table sizes which are always a power of two, to ensure a uniform index distribution in the array. Signed-off-by: Vicent Marti <tanoku@gmail.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
111 lines
2.2 KiB
C
111 lines
2.2 KiB
C
#include "cache.h"
|
|
#include "object.h"
|
|
#include "pack.h"
|
|
#include "pack-objects.h"
|
|
|
|
static uint32_t locate_object_entry_hash(struct packing_data *pdata,
|
|
const unsigned char *sha1,
|
|
int *found)
|
|
{
|
|
uint32_t i, hash, mask = (pdata->index_size - 1);
|
|
|
|
memcpy(&hash, sha1, sizeof(uint32_t));
|
|
i = hash & mask;
|
|
|
|
while (pdata->index[i] > 0) {
|
|
uint32_t pos = pdata->index[i] - 1;
|
|
|
|
if (!hashcmp(sha1, pdata->objects[pos].idx.sha1)) {
|
|
*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;
|
|
|
|
pdata->index = xrealloc(pdata->index, sizeof(uint32_t) * pdata->index_size);
|
|
memset(pdata->index, 0, sizeof(int) * pdata->index_size);
|
|
|
|
entry = pdata->objects;
|
|
|
|
for (i = 0; i < pdata->nr_objects; i++) {
|
|
int found;
|
|
uint32_t ix = locate_object_entry_hash(pdata, entry->idx.sha1, &found);
|
|
|
|
if (found)
|
|
die("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];
|
|
}
|
|
|
|
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;
|
|
pdata->objects = xrealloc(pdata->objects,
|
|
pdata->nr_alloc * sizeof(*new_entry));
|
|
}
|
|
|
|
new_entry = pdata->objects + pdata->nr_objects++;
|
|
|
|
memset(new_entry, 0, sizeof(*new_entry));
|
|
hashcpy(new_entry->idx.sha1, sha1);
|
|
|
|
if (pdata->index_size * 3 <= pdata->nr_objects * 4)
|
|
rehash_objects(pdata);
|
|
else
|
|
pdata->index[index_pos] = pdata->nr_objects;
|
|
|
|
return new_entry;
|
|
}
|