homework-jianmu/include/util/tcache.h

192 lines
6.3 KiB
C

/*
* Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
*
* This program is free software: you can use, redistribute, and/or modify
* it under the terms of the GNU Affero General Public License, version 3
* or later ("AGPL"), as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _TD_UTIL_CACHE_H
#define _TD_UTIL_CACHE_H
#ifdef __cplusplus
extern "C" {
#endif
#include "os.h"
#include "tlockfree.h"
#include "thash.h"
#if defined(_TD_ARM_32)
#define TSDB_CACHE_PTR_KEY TSDB_DATA_TYPE_INT
#define TSDB_CACHE_PTR_TYPE int32_t
#else
#define TSDB_CACHE_PTR_KEY TSDB_DATA_TYPE_BIGINT
#define TSDB_CACHE_PTR_TYPE int64_t
#endif
typedef void (*__cache_free_fn_t)(void*);
typedef void (*__cache_trav_fn_t)(void*, void*);
typedef struct SCacheStatis {
int64_t missCount;
int64_t hitCount;
int64_t totalAccess;
int64_t refreshCount;
} SCacheStatis;
struct STrashElem;
typedef struct SCacheDataNode {
uint64_t addedTime; // the added time when this element is added or updated into cache
uint64_t lifespan; // life duration when this element should be remove from cache
uint64_t expireTime; // expire time
uint64_t signature;
struct STrashElem *pTNodeHeader; // point to trash node head
uint16_t keySize: 15; // max key size: 32kb
bool inTrashcan: 1;// denote if it is in trash or not
uint32_t size; // allocated size for current SCacheDataNode
T_REF_DECLARE()
char *key;
char data[];
} SCacheDataNode;
typedef struct STrashElem {
struct STrashElem *prev;
struct STrashElem *next;
SCacheDataNode *pData;
} STrashElem;
/*
* to accommodate the old data which has the same key value of new one in hashList
* when an new node is put into cache, if an existed one with the same key:
* 1. if the old one does not be referenced, update it.
* 2. otherwise, move the old one to pTrash, addedTime the new one.
*
* when the node in pTrash does not be referenced, it will be release at the expired expiredTime
*/
typedef struct {
int64_t totalSize; // total allocated buffer in this hash table, SCacheObj is not included.
int64_t refreshTime;
STrashElem * pTrash;
char* name;
SCacheStatis statistics;
SHashObj * pHashTable;
__cache_free_fn_t freeFp;
uint32_t numOfElemsInTrash; // number of element in trash
uint8_t deleting; // set the deleting flag to stop refreshing ASAP.
pthread_t refreshWorker;
bool extendLifespan; // auto extend life span when one item is accessed.
int64_t checkTick; // tick used to record the check times of the refresh threads
#if defined(LINUX)
pthread_rwlock_t lock;
#else
pthread_mutex_t lock;
#endif
} SCacheObj;
/**
* initialize the cache object
* @param keyType key type
* @param refreshTimeInSeconds refresh operation interval time, the maximum survival time when one element is expired
* and not referenced by other objects
* @param extendLifespan auto extend lifespan, if accessed
* @param fn free resource callback function
* @return
*/
SCacheObj *taosCacheInit(int32_t keyType, int64_t refreshTimeInSeconds, bool extendLifespan, __cache_free_fn_t fn, const char *cacheName);
/**
* add data into cache
*
* @param handle cache object
* @param key key
* @param pData cached data
* @param dataSize data size
* @param keepTime survival time in second
* @return cached element
*/
void *taosCachePut(SCacheObj *pCacheObj, const void *key, size_t keyLen, const void *pData, size_t dataSize, int durationMS);
/**
* get data from cache
* @param pCacheObj cache object
* @param key key
* @return cached data or NULL
*/
void *taosCacheAcquireByKey(SCacheObj *pCacheObj, const void *key, size_t keyLen);
/**
* Add one reference count for the exist data, and assign this data for a new owner.
* The new owner needs to invoke the taosCacheRelease when it does not need this data anymore.
* This procedure is a faster version of taosCacheAcquireByKey function, which avoids the sideeffect of the problem of
* the data is moved to trash, and taosCacheAcquireByKey will fail to retrieve it again.
*
* @param handle
* @param data
* @return
*/
void *taosCacheAcquireByData(SCacheObj *pCacheObj, void *data);
/**
* transfer the ownership of data in cache to another object without increasing reference count.
* @param handle
* @param data
* @return
*/
void *taosCacheTransfer(SCacheObj *pCacheObj, void **data);
/**
* remove data in cache, the data will not be removed immediately.
* if it is referenced by other object, it will be remain in cache
* @param handle cache object
* @param data not the key, actually referenced data
* @param _remove force model, reduce the ref count and move the data into pTrash
*/
void taosCacheRelease(SCacheObj *pCacheObj, void **data, bool _remove);
/**
* move all data node into trash, clear node in trash can if it is not referenced by any clients
* @param handle
*/
void taosCacheEmpty(SCacheObj *pCacheObj);
/**
* release all allocated memory and destroy the cache object.
*
* This function only set the deleting flag, and the specific work of clean up cache is delegated to
* taosCacheRefresh function, which will executed every SCacheObj->refreshTime sec.
*
* If the value of SCacheObj->refreshTime is too large, the taosCacheRefresh function may not be invoked
* before the main thread terminated, in which case all allocated resources are simply recycled by OS.
*
* @param handle
*/
void taosCacheCleanup(SCacheObj *pCacheObj);
/**
*
* @param pCacheObj
* @param fp
* @return
*/
void taosCacheRefresh(SCacheObj *pCacheObj, __cache_trav_fn_t fp, void* param1);
/**
* stop background refresh worker thread
*/
void taosStopCacheRefreshWorker();
#ifdef __cplusplus
}
#endif
#endif /*_TD_UTIL_CACHE_H*/