/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim: set et sw=2 ts=2: */ /*************************************************************************** * connectionpool.h * * Wed Dec 16 12:20:44 CET 2009 * Copyright 2009 Bent Bisballe Nyeng * deva@aasimon.org ****************************************************************************/ /* * This file is part of Pracro. * * Pracro is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * Pracro is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with Pracro; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #ifndef __PRACRO_CONNECTIONPOOL_H__ #define __PRACRO_CONNECTIONPOOL_H__ #include <list> #include "mutex.h" #include "semaphore.h" template <class T> class ConnectionPool { public: void add(T t); void remove(T t); bool testFree(T t); int numFree(); T borrow(); void giveBack(T t); std::list<T> clear(bool force = true); private: bool contains(std::list<T> &list, T t); Semaphore semaphore; Mutex mutex; std::list<T> active; std::list<T> passive; }; template <class T> class AutoBorrower { public: AutoBorrower(ConnectionPool<T> &pool); ~AutoBorrower(); T get(); private: ConnectionPool<T> &pool; T t; }; // // Implementation is below // template <class T> void ConnectionPool<T>::add(T t) { MutexAutolock lock(mutex); passive.push_back(t); semaphore.post(); } template <class T> bool ConnectionPool<T>::contains(std::list<T> &list, T t) { typename std::list<T>::iterator i = list.begin(); while(i != list.end()) { if(*i == t) return true; i++; } return false; } template <class T> void ConnectionPool<T>::remove(T t) { MutexAutolock lock(mutex); if(contains(passive, t)) { semaphore.post(); passive.remove(t); } } template <class T> bool ConnectionPool<T>::testFree(T t) { bool testfree = false; MutexAutolock lock(mutex); testfree = contains(passive, t); return testfree; } template <class T> int ConnectionPool<T>::numFree() { int num; MutexAutolock lock(mutex); num = passive.size(); return num; } template <class T> T ConnectionPool<T>::borrow() { T t = NULL; semaphore.wait(); { MutexAutolock lock(mutex); t = passive.front(); passive.remove(t); active.push_back(t); } return t; } template <class T> void ConnectionPool<T>::giveBack(T t) { MutexAutolock lock(mutex); if(contains(active, t)) { active.remove(t); passive.push_back(t); semaphore.post(); } } template <class T> std::list<T> ConnectionPool<T>::clear(bool force) { typename std::list<T> lst; if(force == false) { size_t num = 0; { MutexAutolock lock(mutex); num = active.size() + passive.size(); } while(num) { borrow(); num--; } } { MutexAutolock lock(mutex); typename std::list<T>::iterator i; i = active.begin(); while(i != active.end()) { lst.push_back(*i); // i = active.erase(i); semaphore.post(); i++; } active.clear(); i = passive.begin(); while(i != passive.end()) { lst.push_back(*i); // i = passive.erase(i); i++; } passive.clear(); } return lst; } template <class T> AutoBorrower<T>::AutoBorrower(ConnectionPool<T> &p) : pool(p) { t = pool.borrow(); } template <class T> AutoBorrower<T>::~AutoBorrower() { pool.giveBack(t); } template <class T> T AutoBorrower<T>::get() { return t; } #endif/*__PRACRO_CONNECTIONPOOL_H__*/