/*
* Copyright (C) the libgit2 contributors. All rights reserved.
*
* 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 "util.h"
#include "cache.h"
#include "odb.h"
#include "object.h"
#include "git2/oid.h"
GIT__USE_OIDMAP
size_t git_cache__max_object_size[8] = {
0, /* GIT_OBJ__EXT1 */
4096, /* GIT_OBJ_COMMIT */
4096, /* GIT_OBJ_TREE */
0, /* GIT_OBJ_BLOB */
4096, /* GIT_OBJ_TAG */
0, /* GIT_OBJ__EXT2 */
0, /* GIT_OBJ_OFS_DELTA */
0 /* GIT_OBJ_REF_DELTA */
};
int git_cache_init(git_cache *cache)
{
cache->used_memory = 0;
cache->map = git_oidmap_alloc();
git_mutex_init(&cache->lock);
return 0;
}
void git_cache_free(git_cache *cache)
{
git_oidmap_free(cache->map);
git_mutex_free(&cache->lock);
}
/* Call with lock, yo */
static void cache_evict_entries(git_cache *cache, size_t evict_count)
{
uint32_t seed = rand();
/* do not infinite loop if there's not enough entries to evict */
if (evict_count > kh_size(cache->map))
return;
while (evict_count > 0) {
khiter_t pos = seed++ % kh_end(cache->map);
if (kh_exist(cache->map, pos)) {
git_cached_obj *evict = kh_val(cache->map, pos);
evict_count--;
cache->used_memory -= evict->size;
git_cached_obj_decref(evict);
kh_del(oid, cache->map, pos);
}
}
}
static bool cache_should_store(git_otype object_type, size_t object_size)
{
size_t max_size = git_cache__max_object_size[object_type];
if (max_size == 0 || object_size > max_size)
return false;
return true;
}
static void *cache_get(git_cache *cache, const git_oid *oid, unsigned int flags)
{
khiter_t pos;
git_cached_obj *entry = NULL;
if (git_mutex_lock(&cache->lock) < 0)
return NULL;
pos = kh_get(oid, cache->map, oid);
if (pos != kh_end(cache->map)) {
entry = kh_val(cache->map, pos);
if (flags && entry->flags != flags) {
entry = NULL;
} else {
git_cached_obj_incref(entry);
}
}
git_mutex_unlock(&cache->lock);
return entry;
}
static void *cache_store(git_cache *cache, git_cached_obj *entry)
{
khiter_t pos;
git_cached_obj_incref(entry);
if (!cache_should_store(entry->type, entry->size))
return entry;
if (git_mutex_lock(&cache->lock) < 0)
return entry;
pos = kh_get(oid, cache->map, &entry->oid);
/* not found */
if (pos == kh_end(cache->map)) {
int rval;
pos = kh_put(oid, cache->map, &entry->oid, &rval);
if (rval >= 0) {
kh_key(cache->map, pos) = &entry->oid;
kh_val(cache->map, pos) = entry;
git_cached_obj_incref(entry);
cache->used_memory += entry->size;
}
}
/* found */
else {
git_cached_obj *stored_entry = kh_val(cache->map, pos);
if (stored_entry->flags == entry->flags) {
git_cached_obj_decref(entry);
git_cached_obj_incref(stored_entry);
entry = stored_entry;
} else if (stored_entry->flags == GIT_CACHE_STORE_RAW &&
entry->flags == GIT_CACHE_STORE_PARSED) {
git_cached_obj_decref(stored_entry);
git_cached_obj_incref(entry);
kh_key(cache->map, pos) = &entry->oid;
kh_val(cache->map, pos) = entry;
} else {
/* NO OP */
}
}
git_mutex_unlock(&cache->lock);
return entry;
}
void *git_cache_store_raw(git_cache *cache, git_odb_object *entry)
{
entry->cached.flags = GIT_CACHE_STORE_RAW;
return cache_store(cache, (git_cached_obj *)entry);
}
void *git_cache_store_parsed(git_cache *cache, git_object *entry)
{
entry->cached.flags = GIT_CACHE_STORE_PARSED;
return cache_store(cache, (git_cached_obj *)entry);
}
git_odb_object *git_cache_get_raw(git_cache *cache, const git_oid *oid)
{
return cache_get(cache, oid, GIT_CACHE_STORE_RAW);
}
git_object *git_cache_get_parsed(git_cache *cache, const git_oid *oid)
{
return cache_get(cache, oid, GIT_CACHE_STORE_PARSED);
}
void *git_cache_get_any(git_cache *cache, const git_oid *oid)
{
return cache_get(cache, oid, GIT_CACHE_STORE_ANY);
}
void git_cached_obj_decref(void *_obj)
{
git_cached_obj *obj = _obj;
if (git_atomic_dec(&obj->refcount) == 0) {
switch (obj->flags) {
case GIT_CACHE_STORE_RAW:
git_odb_object__free(_obj);
break;
case GIT_CACHE_STORE_PARSED:
git_object__free(_obj);
break;
default:
git__free(_obj);
break;
}
}
}
