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# cpool.h

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    00001
    00002
    00003
    00004 /***********************************************************************
    00005  Copyright (c) 2007-2008 by Educational Technology Resources, Inc. and
    00006  (c) 2007 by Jonathan Wakely.  Others may also hold copyrights on
    00007  code in this file.  See the CREDITS file in the top directory of
    00008  the distribution for details.
    00009
    00010  This file is part of MySQL++.
    00011
    00012  MySQL++ is free software; you can redistribute it and/or modify it
    00013  under the terms of the GNU Lesser General Public License as published
    00014  by the Free Software Foundation; either version 2.1 of the License, or
    00015  (at your option) any later version.
    00016
    00017  MySQL++ is distributed in the hope that it will be useful, but WITHOUT
    00018  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    00019  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
    00020  License for more details.
    00021
    00022  You should have received a copy of the GNU Lesser General Public
    00023  License along with MySQL++; if not, write to the Free Software
    00024  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
    00025  USA
    00026 ***********************************************************************/
    00027
    00028 #if !defined(MYSQLPP_CPOOL_H)
    00029 #define MYSQLPP_CPOOL_H
    00030
    00031 #include "beemutex.h"
    00032
    00033 #include <list>
    00034
    00035 #include <assert.h>
    00036 #include <time.h>
    00037
    00038 namespace mysqlpp {
    00039
    00040 #if !defined(DOXYGEN_IGNORE)
    00041 // Make Doxygen ignore this
    00042 class MYSQLPP_EXPORT Connection;
    00043 #endif
    00044
    00067
    00068 class MYSQLPP_EXPORT ConnectionPool
    00069 {
    00070 public:
    00072         ConnectionPool() { }
    00073
    00078         virtual ~ConnectionPool() { assert(empty()); }
    00079
    00081         bool empty() const { return pool_.empty(); }
    00082
    00095         Connection* grab();
    00096
    00109         virtual void release(const Connection* pc);
    00110
    00112         void shrink() { clear(false); }
    00113
    00114 protected:
    00123         void clear(bool all = true);
    00124
    00135         virtual Connection* create() = 0;
    00136
    00144         virtual void destroy(Connection*) = 0;
    00145
    00154         virtual unsigned int max_idle_time() = 0;
    00155
    00157         size_t size() const { return pool_.size(); }
    00158
    00159 private:
    00161         struct ConnectionInfo {
    00162                 Connection* conn;
    00163                 time_t last_used;
    00164                 bool in_use;
    00165
    00166                 ConnectionInfo(Connection* c) :
    00167                 conn(c),
    00168                 last_used(time(0)),
    00169                 in_use(true)
    00170                 {
    00171                 }
    00172
    00173                 // Strict weak ordering for ConnectionInfo objects.
    00174                 //
    00175                 // This ordering defines all in-use connections to be "less
    00176                 // than" those not in use.  Within each group, connections
    00177                 // less recently touched are less than those more recent.
    00178                 bool operator<(const ConnectionInfo& rhs) const
    00179                 {
    00180                         const ConnectionInfo& lhs = *this;
    00181                         return lhs.in_use == rhs.in_use ?
    00182                                         lhs.last_used < rhs.last_used :
    00183                                         lhs.in_use;
    00184                 }
    00185         };
    00186         typedef std::list<ConnectionInfo> PoolT;
    00187         typedef PoolT::iterator PoolIt;
    00188
    00190         Connection* find_mru();
    00191         void remove_old_connections();
    00192
    00194         PoolT pool_;
    00195         BeecryptMutex mutex_;
    00196 };
    00197
    00198 } // end namespace mysqlpp
    00199
    00200 #endif // !defined(MYSQLPP_CPOOL_H)
    00201