TarsCpp/servant/jmem/jmem_policy.h

/**
 * Tencent is pleased to support the open source community by making Tars available.
 *
 * Copyright (C) 2016THL A29 Limited, a Tencent company. All rights reserved.
 *
 * Licensed under the BSD 3-Clause License (the "License"); you may not use this file except 
 * in compliance with the License. You may obtain a copy of the License at
 *
 * https://opensource.org/licenses/BSD-3-Clause
 *
 * Unless required by applicable law or agreed to in writing, software distributed 
 * under the License 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.
 */

#ifndef _JMEM_POLICY_H
#define _JMEM_POLICY_H

#include "util/tc_thread_mutex.h"
#include "util/tc_sem_mutex.h"
#include "util/tc_shm.h"
#include "util/tc_mmap.h"

namespace tars
{
//////////////////////////////////////////////////////////////////////
// 存储策略: 内存, 共享内存, mmap(文件)

/**
 * 内存存储
 */
template<typename T, typename LockPolicy>
class MemStorePolicy : public LockPolicy
{
public:
    /**
    * 初始化
    * @param pAddr: 指令队列空间的指针
    * @param iSize: 空间的指针
    */
    void create(void *pAddr, size_t iSize)
    {
        _t.create(pAddr,iSize);
    }

    /**
    * 连接上队列
    * @param pAddr: 指令队列空间的指针
    * @param iSize: 空间的指针
    */
    void connect(void *pAddr, size_t iSize)
    {
        _t.connect(pAddr,iSize);
    }

protected:
    T   _t;
};

/**
 * 共享内存存储
 */
template<typename T, typename LockPolicy>
class ShmStorePolicy : public LockPolicy
{
public:
    /**
     * 初始化共享存储
     * @param iShmKey
     * @param iSize
     */
    void initStore(key_t iShmKey, size_t iSize)
    {
        _shm.init(iSize, iShmKey);
        if(_shm.iscreate())
        {
            _t.create(_shm.getPointer(), iSize);
        }
        else
        {
            _t.connect(_shm.getPointer(), iSize);
        }
    }

    /**
     * 释放共享内存
     */
    void release()
    {
        _shm.del();
    }
protected:
    TC_Shm  _shm;
    T       _t;
};

/**
 * 文件存储
 */
template<typename T, typename LockPolicy>
class FileStorePolicy : public LockPolicy
{
public:
    /**
     * 初始化文件
     * @param file, 文件路径
     * @param iSize, 文件大小
     */
    void initStore(const char *file, size_t iSize)
    {
        _file = file;
        _mmap.mmap(file, iSize);
        if(_mmap.iscreate())
        {
            _t.create(_mmap.getPointer(), iSize);
        }
        else
        {
            _t.connect(_mmap.getPointer(), iSize);
        }
    }

    /**
     * 扩展空间, 目前只对hashmap有效
     */
    int expand(size_t iSize)
    {
        TC_LockT<typename LockPolicy::Mutex> lock(LockPolicy::mutex());

        TC_Mmap m(false);
        m.mmap(_file.c_str(), iSize);

        int ret = _t.append(m.getPointer(), iSize);

        if(ret == 0)
        {
            _mmap.munmap();
            _mmap = m;
            _mmap.setOwner(true);
        }
        else
        {
            m.munmap();
        }

        return ret;
    }

protected:
    string  _file;
    TC_Mmap _mmap;
    T       _t;
};

//////////////////////////////////////////////////////////////////////
// 锁策略: 无锁, 线程锁, 进程锁

/**
 * 无锁
 */
class EmptyLockPolicy
{
public:
    typedef TC_EmptyMutex Mutex;
    Mutex &mutex()     { return _mutex; }

protected:
    Mutex _mutex;
};

/**
 * 线程锁策略
 */
class ThreadLockPolicy
{
public:
    typedef TC_ThreadMutex Mutex;
    Mutex &mutex()     { return _mutex; }

protected:
    Mutex _mutex;
};

/**
 * 进程锁策略
 */
class SemLockPolicy
{
public:
    typedef TC_SemMutex Mutex;
    void initLock(key_t iSemKey)    { return _mutex.init(iSemKey); }
    Mutex &mutex()                  { return _mutex; }

protected:
    Mutex _mutex;
};

}

#endif