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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.txt file in the top directory
    00008  of 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
    00106         virtual Connection* exchange(const Connection* pc);
    00107
    00120         virtual Connection* grab();
    00121
    00137         virtual void release(const Connection* pc);
    00138
    00150         void remove(const Connection* pc);
    00151
    00162         virtual Connection* safe_grab();
    00163
    00165         void shrink() { clear(false); }
    00166
    00167 protected:
    00176         void clear(bool all = true);
    00177
    00188         virtual Connection* create() = 0;
    00189
    00197         virtual void destroy(Connection*) = 0;
    00198
    00207         virtual unsigned int max_idle_time() = 0;
    00208
    00210         size_t size() const { return pool_.size(); }
    00211
    00212 private:
    00214         struct ConnectionInfo {
    00215                 Connection* conn;
    00216                 time_t last_used;
    00217                 bool in_use;
    00218
    00219                 ConnectionInfo(Connection* c) :
    00220                 conn(c),
    00221                 last_used(time(0)),
    00222                 in_use(true)
    00223                 {
    00224                 }
    00225
    00226                 // Strict weak ordering for ConnectionInfo objects.
    00227                 //
    00228                 // This ordering defines all in-use connections to be "less
    00229                 // than" those not in use.  Within each group, connections
    00230                 // less recently touched are less than those more recent.
    00231                 bool operator<(const ConnectionInfo& rhs) const
    00232                 {
    00233                         const ConnectionInfo& lhs = *this;
    00234                         return lhs.in_use == rhs.in_use ?
    00235                                         lhs.last_used < rhs.last_used :
    00236                                         lhs.in_use;
    00237                 }
    00238         };
    00239         typedef std::list<ConnectionInfo> PoolT;
    00240         typedef PoolT::iterator PoolIt;
    00241
    00243         Connection* find_mru();
    00244         void remove(const PoolIt& it);
    00245         void remove_old_connections();
    00246
    00248         PoolT pool_;
    00249         BeecryptMutex mutex_;
    00250 };
    00251
    00252 } // end namespace mysqlpp
    00253
    00254 #endif // !defined(MYSQLPP_CPOOL_H)
    00255