connection_manager.h

#ifndef _CONNECTION_MANAGER_H
#define _CONNECTION_MANAGER_H
/*
 * Fledge storage service.
 *
 * Copyright (c) 2017 OSisoft, LLC
 *
 * Released under the Apache 2.0 Licence
 *
 * Author: Mark Riddoch
 */

#include <plugin_api.h>
#include <list>
#include <mutex>

class Connection;

class MemConnectionManager {
    public:
        static MemConnectionManager  *getInstance();
        void                         growPool(unsigned int);
        unsigned int                 shrinkPool(unsigned int);
        Connection                   *allocate();
        void                         release(Connection *);
        void                 shutdown();
        void                 setError(const char *, const char *, bool);
        PLUGIN_ERROR             *getError()
                         {
                        return &lastError;
                         }
        void                 setPersist(bool persist, const std::string& filename = "")
                         {
                             m_persist = persist;
                             m_filename = filename;
                         }
        bool                 persist() { return m_persist; };
        std::string          filename() { return m_filename; };
        void                 setPurgeBlockSize(unsigned long purgeBlockSize);

    private:
        MemConnectionManager();
        static MemConnectionManager  *instance;
        std::list<Connection *>      idle;
        std::list<Connection *>      inUse;
        std::mutex                   idleLock;
        std::mutex                   inUseLock;
        std::mutex                   errorLock;
        PLUGIN_ERROR             lastError;
        bool                 m_trace;
        bool                 m_persist;
        std::string          m_filename;
        unsigned long            m_purgeBlockSize;
};

#endif