urbackup_backend/external/aws-cpp-sdk/include/aws/common/cache.h
2021-07-07 18:47:38 +02:00

95 lines
2.9 KiB
C
Executable File

#ifndef AWS_COMMON_CACHE_H
#define AWS_COMMON_CACHE_H
/*
* Copyright 2010-2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#include <aws/common/linked_hash_table.h>
struct aws_cache;
struct aws_cache_vtable {
void (*destroy)(struct aws_cache *cache);
int (*find)(struct aws_cache *cache, const void *key, void **p_value);
int (*put)(struct aws_cache *cache, const void *key, void *p_value);
int (*remove)(struct aws_cache *cache, const void *key);
void (*clear)(struct aws_cache *cache);
size_t (*get_element_count)(const struct aws_cache *cache);
};
/**
* Base stucture for caches, used the linked hash table implementation.
*/
struct aws_cache {
struct aws_allocator *allocator;
const struct aws_cache_vtable *vtable;
struct aws_linked_hash_table table;
size_t max_items;
void *impl;
};
/* Default implementations */
void aws_cache_base_default_destroy(struct aws_cache *cache);
int aws_cache_base_default_find(struct aws_cache *cache, const void *key, void **p_value);
int aws_cache_base_default_remove(struct aws_cache *cache, const void *key);
void aws_cache_base_default_clear(struct aws_cache *cache);
size_t aws_cache_base_default_get_element_count(const struct aws_cache *cache);
AWS_EXTERN_C_BEGIN
/**
* Cleans up the cache. Elements in the cache will be evicted and cleanup
* callbacks will be invoked.
*/
AWS_COMMON_API
void aws_cache_destroy(struct aws_cache *cache);
/**
* Finds element in the cache by key. If found, *p_value will hold the stored value, and AWS_OP_SUCCESS will be
* returned. If not found, AWS_OP_SUCCESS will be returned and *p_value will be NULL.
*
* If any errors occur AWS_OP_ERR will be returned.
*/
AWS_COMMON_API
int aws_cache_find(struct aws_cache *cache, const void *key, void **p_value);
/**
* Puts `p_value` at `key`. If an element is already stored at `key` it will be replaced. If the cache is already full,
* an item will be removed based on the cache policy.
*/
AWS_COMMON_API
int aws_cache_put(struct aws_cache *cache, const void *key, void *p_value);
/**
* Removes item at `key` from the cache.
*/
AWS_COMMON_API
int aws_cache_remove(struct aws_cache *cache, const void *key);
/**
* Clears all items from the cache.
*/
AWS_COMMON_API
void aws_cache_clear(struct aws_cache *cache);
/**
* Returns the number of elements in the cache.
*/
AWS_COMMON_API
size_t aws_cache_get_element_count(const struct aws_cache *cache);
AWS_EXTERN_C_END
#endif /* AWS_COMMON_FIFO_CACHE_H */