mirror of
https://github.com/git/git.git
synced 2024-11-24 10:26:17 +08:00
83f0412f3f
When growing the table, take the opportunity to "compact" it by removing entries with NULL decoration. Users may have "removed" decorations by passing NULL to insert_decoration. An object's table entry can't actually be removed during normal operation, as it would break the linear hash collision search. But we can remove NULL decoration entries when rebuilding the table. Signed-off-by: Kevin Bracey <kevin@bracey.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
89 lines
1.8 KiB
C
89 lines
1.8 KiB
C
/*
|
|
* decorate.c - decorate a git object with some arbitrary
|
|
* data.
|
|
*/
|
|
#include "cache.h"
|
|
#include "object.h"
|
|
#include "decorate.h"
|
|
|
|
static unsigned int hash_obj(const struct object *obj, unsigned int n)
|
|
{
|
|
unsigned int hash;
|
|
|
|
memcpy(&hash, obj->sha1, sizeof(unsigned int));
|
|
return hash % n;
|
|
}
|
|
|
|
static void *insert_decoration(struct decoration *n, const struct object *base, void *decoration)
|
|
{
|
|
int size = n->size;
|
|
struct object_decoration *hash = n->hash;
|
|
unsigned int j = hash_obj(base, size);
|
|
|
|
while (hash[j].base) {
|
|
if (hash[j].base == base) {
|
|
void *old = hash[j].decoration;
|
|
hash[j].decoration = decoration;
|
|
return old;
|
|
}
|
|
if (++j >= size)
|
|
j = 0;
|
|
}
|
|
hash[j].base = base;
|
|
hash[j].decoration = decoration;
|
|
n->nr++;
|
|
return NULL;
|
|
}
|
|
|
|
static void grow_decoration(struct decoration *n)
|
|
{
|
|
int i;
|
|
int old_size = n->size;
|
|
struct object_decoration *old_hash = n->hash;
|
|
|
|
n->size = (old_size + 1000) * 3 / 2;
|
|
n->hash = xcalloc(n->size, sizeof(struct object_decoration));
|
|
n->nr = 0;
|
|
|
|
for (i = 0; i < old_size; i++) {
|
|
const struct object *base = old_hash[i].base;
|
|
void *decoration = old_hash[i].decoration;
|
|
|
|
if (!decoration)
|
|
continue;
|
|
insert_decoration(n, base, decoration);
|
|
}
|
|
free(old_hash);
|
|
}
|
|
|
|
/* Add a decoration pointer, return any old one */
|
|
void *add_decoration(struct decoration *n, const struct object *obj,
|
|
void *decoration)
|
|
{
|
|
int nr = n->nr + 1;
|
|
|
|
if (nr > n->size * 2 / 3)
|
|
grow_decoration(n);
|
|
return insert_decoration(n, obj, decoration);
|
|
}
|
|
|
|
/* Lookup a decoration pointer */
|
|
void *lookup_decoration(struct decoration *n, const struct object *obj)
|
|
{
|
|
unsigned int j;
|
|
|
|
/* nothing to lookup */
|
|
if (!n->size)
|
|
return NULL;
|
|
j = hash_obj(obj, n->size);
|
|
for (;;) {
|
|
struct object_decoration *ref = n->hash + j;
|
|
if (ref->base == obj)
|
|
return ref->decoration;
|
|
if (!ref->base)
|
|
return NULL;
|
|
if (++j == n->size)
|
|
j = 0;
|
|
}
|
|
}
|