cppdb/pool.h

//                                                                             
//  Copyright (C) 2010-2011  Artyom Beilis (Tonkikh) <artyomtnk@yahoo.com>     
//                                                                             
//  Distributed under:
//
//                   the Boost Software License, Version 1.0.
//              (See accompanying file LICENSE_1_0.txt or copy at 
//                     http://www.boost.org/LICENSE_1_0.txt)
//
//  or (at your opinion) under:
//
//                               The MIT License
//                 (See accompanying file MIT.txt or a copy at
//              http://www.opensource.org/licenses/mit-license.php)
//
#ifndef CPPDB_POOL_H
#define CPPDB_POOL_H

#include <cppdb/defs.h>
#include <cppdb/ref_ptr.h>
#include <cppdb/mutex.h>
#include <cppdb/utils.h>
#include <memory>
#include <list>


namespace cppdb {
        class connection_info;
        namespace backend {
                class connection;
        }
        
        class CPPDB_API pool : public ref_counted {
                pool();
                pool(pool const &);
                void operator=(pool const &);
                pool(connection_info const &ci);
        public:
                static ref_ptr<pool> create(std::string const &connection_string);
                static ref_ptr<pool> create(connection_info const &ci);
                
                typedef ref_ptr<pool> pointer;

                ~pool();

                ref_ptr<backend::connection> open();
                void gc();

                void clear();

                void put(backend::connection *c_in);
        private:
                ref_ptr<backend::connection> get();

                struct data;
                std::auto_ptr<data> d;
                
                struct entry {
                        entry() : last_used(0) {}
                        ref_ptr<backend::connection> conn;
                        std::time_t last_used;
                };

                typedef std::list<entry> pool_type;
                // non-mutable members
                
                size_t limit_;
                int life_time_;
                connection_info ci_;
                
                // mutex protected begin
                mutex lock_;
                size_t size_;
                pool_type pool_;
                // mutex protected end
                
        };
}


#endif