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/**
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0.
*/
#include <aws/common/lifo_cache.h>
static int s_lifo_cache_put(struct aws_cache *cache, const void *key, void *p_value);
static struct aws_cache_vtable s_lifo_cache_vtable = {
.destroy = aws_cache_base_default_destroy,
.find = aws_cache_base_default_find,
.put = s_lifo_cache_put,
.remove = aws_cache_base_default_remove,
.clear = aws_cache_base_default_clear,
.get_element_count = aws_cache_base_default_get_element_count,
};
struct aws_cache *aws_cache_new_lifo(
struct aws_allocator *allocator,
aws_hash_fn *hash_fn,
aws_hash_callback_eq_fn *equals_fn,
aws_hash_callback_destroy_fn *destroy_key_fn,
aws_hash_callback_destroy_fn *destroy_value_fn,
size_t max_items) {
AWS_ASSERT(allocator);
AWS_ASSERT(max_items);
struct aws_cache *lifo_cache = aws_mem_calloc(allocator, 1, sizeof(struct aws_cache));
if (!lifo_cache) {
return NULL;
}
lifo_cache->allocator = allocator;
lifo_cache->max_items = max_items;
lifo_cache->vtable = &s_lifo_cache_vtable;
if (aws_linked_hash_table_init(
&lifo_cache->table, allocator, hash_fn, equals_fn, destroy_key_fn, destroy_value_fn, max_items)) {
return NULL;
}
return lifo_cache;
}
/* lifo cache put implementation */
static int s_lifo_cache_put(struct aws_cache *cache, const void *key, void *p_value) {
if (aws_linked_hash_table_put(&cache->table, key, p_value)) {
return AWS_OP_ERR;
}
/* Manage the space if we actually added a new element and the cache is full. */
if (aws_linked_hash_table_get_element_count(&cache->table) > cache->max_items) {
/* we're over the cache size limit. Remove whatever is in the one before the back of the linked_hash_table,
* which was the latest element before we put the new one */
const struct aws_linked_list *list = aws_linked_hash_table_get_iteration_list(&cache->table);
struct aws_linked_list_node *node = aws_linked_list_back(list);
if (!node->prev) {
return AWS_OP_SUCCESS;
}
struct aws_linked_hash_table_node *table_node =
AWS_CONTAINER_OF(node->prev, struct aws_linked_hash_table_node, node);
return aws_linked_hash_table_remove(&cache->table, table_node->key);
}
return AWS_OP_SUCCESS;
}
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