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/*
* Copyright (C) 2009-2011 the libgit2 contributors
*
* This file is part of libgit2, distributed under the GNU GPL v2 with
* a Linking Exception. For full terms see the included COPYING file.
*/
#include "common.h"
#include "repository.h"
#include "commit.h"
#include "thread-utils.h"
#include "cache.h"
int git_cache_init(git_cache *cache, size_t size, git_cached_obj_freeptr free_ptr)
{
size_t i;
if (size < 8)
size = 8;
/* round up size to closest power of 2 */
size--;
size |= size >> 1;
size |= size >> 2;
size |= size >> 4;
size |= size >> 8;
size |= size >> 16;
cache->size_mask = size;
cache->lru_count = 0;
cache->free_obj = free_ptr;
cache->nodes = git__malloc((size + 1) * sizeof(cache_node));
if (cache->nodes == NULL)
return GIT_ENOMEM;
for (i = 0; i < (size + 1); ++i) {
git_mutex_init(&cache->nodes[i].lock);
cache->nodes[i].ptr = NULL;
}
return GIT_SUCCESS;
}
void git_cache_free(git_cache *cache)
{
size_t i;
for (i = 0; i < (cache->size_mask + 1); ++i) {
if (cache->nodes[i].ptr)
git_cached_obj_decref(cache->nodes[i].ptr, cache->free_obj);
git_mutex_free(&cache->nodes[i].lock);
}
git__free(cache->nodes);
}
void *git_cache_get(git_cache *cache, const git_oid *oid)
{
uint32_t hash;
cache_node *node = NULL;
void *result = NULL;
memcpy(&hash, oid->id, sizeof(hash));
node = &cache->nodes[hash & cache->size_mask];
git_mutex_lock(&node->lock);
{
if (node->ptr && git_cached_obj_compare(node->ptr, oid) == 0) {
git_cached_obj_incref(node->ptr);
result = node->ptr;
}
}
git_mutex_unlock(&node->lock);
return result;
}
void *git_cache_try_store(git_cache *cache, void *entry)
{
uint32_t hash;
const git_oid *oid;
cache_node *node = NULL;
oid = &((git_cached_obj*)entry)->oid;
memcpy(&hash, oid->id, sizeof(hash));
node = &cache->nodes[hash & cache->size_mask];
/* increase the refcount on this object, because
* the cache now owns it */
git_cached_obj_incref(entry);
git_mutex_lock(&node->lock);
if (node->ptr == NULL) {
node->ptr = entry;
} else if (git_cached_obj_compare(node->ptr, oid) == 0) {
git_cached_obj_decref(entry, cache->free_obj);
entry = node->ptr;
} else {
git_cached_obj_decref(node->ptr, cache->free_obj);
node->ptr = entry;
}
/* increase the refcount again, because we are
* returning it to the user */
git_cached_obj_incref(entry);
git_mutex_unlock(&node->lock);
return entry;
}
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