OpenWalnut
1.4.0
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00001 //--------------------------------------------------------------------------- 00002 // 00003 // Project: OpenWalnut ( http://www.openwalnut.org ) 00004 // 00005 // Copyright 2009 OpenWalnut Community, BSV@Uni-Leipzig and CNCF@MPI-CBS 00006 // For more information see http://www.openwalnut.org/copying 00007 // 00008 // This file is part of OpenWalnut. 00009 // 00010 // OpenWalnut is free software: you can redistribute it and/or modify 00011 // it under the terms of the GNU Lesser General Public License as published by 00012 // the Free Software Foundation, either version 3 of the License, or 00013 // (at your option) any later version. 00014 // 00015 // OpenWalnut is distributed in the hope that it will be useful, 00016 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00017 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00018 // GNU Lesser General Public License for more details. 00019 // 00020 // You should have received a copy of the GNU Lesser General Public License 00021 // along with OpenWalnut. If not, see <http://www.gnu.org/licenses/>. 00022 // 00023 //--------------------------------------------------------------------------- 00024 00025 #ifndef WCONDITIONONESHOT_H 00026 #define WCONDITIONONESHOT_H 00027 00028 #include <boost/thread.hpp> 00029 00030 #include "WCondition.h" 00031 00032 00033 /** 00034 * Implements a WCondition, but can be fired only ONCE. This is useful if you want to have a thread waiting for a condition but 00035 * you can not assure that the thread already waits when you set the condition. This would cause the thread to wait endlessly 00036 * because he does not know that you already fired it. Implementation is simple. The constructor uses a unique lock (write lock) 00037 * on a mutex. All waiting threads try to get a read lock which is not possible as long it is write-locked. The notify method 00038 * releases the write lock and all waiting threads can continue. 00039 */ 00040 class WConditionOneShot: public WCondition 00041 { 00042 friend class WConditionOneShot_test; 00043 public: 00044 /** 00045 * Default constructor. 00046 */ 00047 WConditionOneShot(); 00048 00049 /** 00050 * Destructor. 00051 */ 00052 virtual ~WConditionOneShot(); 00053 00054 /** 00055 * Wait for the condition. Sets the calling thread asleep. 00056 */ 00057 virtual void wait() const; 00058 00059 /** 00060 * Notifies all waiting threads. 00061 */ 00062 virtual void notify(); 00063 00064 protected: 00065 /** 00066 * Locked as long the condition was not fired. 00067 */ 00068 boost::unique_lock<boost::shared_mutex> m_lock; 00069 00070 private: 00071 }; 00072 00073 #endif // WCONDITIONONESHOT_H 00074