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#include "cache.h"
#include "object.h"
int track_object_refs = 0;
static unsigned int refs_hash_size, nr_object_refs;
static struct object_refs **refs_hash;
static unsigned int hash_obj(struct object *obj, unsigned int n)
{
unsigned int hash = *(unsigned int *)obj->sha1;
return hash % n;
}
static void insert_ref_hash(struct object_refs *ref, struct object_refs **hash, unsigned int size)
{
int j = hash_obj(ref->base, size);
while (hash[j]) {
j++;
if (j >= size)
j = 0;
}
hash[j] = ref;
}
static void grow_refs_hash(void)
{
int i;
int new_hash_size = (refs_hash_size + 1000) * 3 / 2;
struct object_refs **new_hash;
new_hash = calloc(new_hash_size, sizeof(struct object_refs *));
for (i = 0; i < refs_hash_size; i++) {
struct object_refs *ref = refs_hash[i];
if (!ref)
continue;
insert_ref_hash(ref, new_hash, new_hash_size);
}
free(refs_hash);
refs_hash = new_hash;
refs_hash_size = new_hash_size;
}
static void add_object_refs(struct object *obj, struct object_refs *ref)
{
int nr = nr_object_refs + 1;
if (nr > refs_hash_size * 2 / 3)
grow_refs_hash();
ref->base = obj;
insert_ref_hash(ref, refs_hash, refs_hash_size);
nr_object_refs = nr;
}
struct object_refs *lookup_object_refs(struct object *obj)
{
int j = hash_obj(obj, refs_hash_size);
struct object_refs *ref;
while ((ref = refs_hash[j]) != NULL) {
if (ref->base == obj)
break;
j++;
if (j >= refs_hash_size)
j = 0;
}
return ref;
}
struct object_refs *alloc_object_refs(unsigned count)
{
struct object_refs *refs;
size_t size = sizeof(*refs) + count*sizeof(struct object *);
refs = xcalloc(1, size);
refs->count = count;
return refs;
}
static int compare_object_pointers(const void *a, const void *b)
{
const struct object * const *pa = a;
const struct object * const *pb = b;
if (*pa == *pb)
return 0;
else if (*pa < *pb)
return -1;
else
return 1;
}
void set_object_refs(struct object *obj, struct object_refs *refs)
{
unsigned int i, j;
/* Do not install empty list of references */
if (refs->count < 1) {
free(refs);
return;
}
/* Sort the list and filter out duplicates */
qsort(refs->ref, refs->count, sizeof(refs->ref[0]),
compare_object_pointers);
for (i = j = 1; i < refs->count; i++) {
if (refs->ref[i] != refs->ref[i - 1])
refs->ref[j++] = refs->ref[i];
}
if (j < refs->count) {
/* Duplicates were found - reallocate list */
size_t size = sizeof(*refs) + j*sizeof(struct object *);
refs->count = j;
refs = xrealloc(refs, size);
}
for (i = 0; i < refs->count; i++)
refs->ref[i]->used = 1;
add_object_refs(obj, refs);
}
void mark_reachable(struct object *obj, unsigned int mask)
{
const struct object_refs *refs;
if (!track_object_refs)
die("cannot do reachability with object refs turned off");
/* nothing to lookup */
if (!refs_hash_size)
return;
/* If we've been here already, don't bother */
if (obj->flags & mask)
return;
obj->flags |= mask;
refs = lookup_object_refs(obj);
if (refs) {
unsigned i;
for (i = 0; i < refs->count; i++)
mark_reachable(refs->ref[i], mask);
}
}
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