libdap++ Updated for version 3.8.2
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00001 00002 // -*- mode: c++; c-basic-offset:4 -*- 00003 00004 // This file is part of libdap, A C++ implementation of the OPeNDAP Data 00005 // Access Protocol. 00006 00007 // Copyright (c) 2002,2003 OPeNDAP, Inc. 00008 // Author: James Gallagher <jgallagher@opendap.org> 00009 // 00010 // This library is free software; you can redistribute it and/or 00011 // modify it under the terms of the GNU Lesser General Public 00012 // License as published by the Free Software Foundation; either 00013 // version 2.1 of the License, or (at your option) any later version. 00014 // 00015 // This library 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 GNU 00018 // Lesser General Public License for more details. 00019 // 00020 // You should have received a copy of the GNU Lesser General Public 00021 // License along with this library; if not, write to the Free Software 00022 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 00023 // 00024 // You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112. 00025 00026 #ifndef signal_handler_h 00027 #define signal_handler_h 00028 00029 #include <signal.h> 00030 00031 #include "EventHandler.h" 00032 #include "InternalErr.h" 00033 00034 namespace libdap 00035 { 00036 00037 typedef void Sigfunc(int); // Plauger, 1992 00038 00066 class SignalHandler 00067 { 00068 private: 00069 // Ensure we're a Singleton. 00070 SignalHandler() 00071 {} 00072 00073 // Singleton pointer. 00074 static SignalHandler *d_instance; 00075 00076 // Table of pointers to instances of EventHandlers. Since EventHandler is 00077 // abstract, the pointers will actually reference instances that are 00078 // children of EventHandler. NSIG is defined in signal.h but this may be 00079 // a portability issue. 00080 static EventHandler *d_signal_handlers[NSIG]; 00081 00082 // This array holds the old signal handlers. Once the handler in 00083 // d_signal_handler[signum] is run, look here to see what the original 00084 // action was. This is important since libdap++ is often embedded in code 00085 // that already has a non-default signal handler for things like SIGINT. 00086 static Sigfunc *d_old_handlers[NSIG]; 00087 00088 // Entry point adapter installed into sigaction(). This must be static 00089 // method (or a regular C-function) to conform to sigaction's interface. 00090 // this is the part of SignalHandler that uses the Adapter pattern. 00091 static void dispatcher(int signum); 00092 00093 // Delete the global instance. Call this with atexit(). 00094 static void delete_instance(); 00095 00096 // Call this using pthread_once() to ensure there's only one instance 00097 // when running in a MT world. 00098 static void initialize_instance(); 00099 00100 friend class SignalHandlerTest; 00101 friend class HTTPCacheTest; 00102 00103 public: 00104 static SignalHandler *instance(); 00105 00107 virtual ~SignalHandler() 00108 {} 00109 00110 EventHandler *register_handler(int signum, EventHandler *eh, 00111 bool override = false); 00112 00113 EventHandler *remove_handler(int signum); 00114 }; 00115 00116 } // namespace libdap 00117 00118 #endif // signal_handler_h