OPeNDAP Hyrax Back End Server (BES)
Updated for version 3.8.3
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00001 // BESPlugin.h 00002 00003 // This file is part of bes, A C++ back-end server implementation framework 00004 // for the OPeNDAP Data Access Protocol. 00005 00006 // Copyright (c) 2004-2009 University Corporation for Atmospheric Research 00007 // Author: Patrick West <pwest@ucar.edu> and Jose Garcia <jgarcia@ucar.edu> 00008 // and James Gallagher <jgallagher@gso.uri.edu> 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 University Corporation for Atmospheric Research at 00025 // 3080 Center Green Drive, Boulder, CO 80301 00026 00027 // (c) COPYRIGHT University Corporation for Atmospheric Research 2004-2005 00028 // Please read the full copyright statement in the file COPYRIGHT_UCAR. 00029 // 00030 // Authors: 00031 // pwest Patrick West <pwest@ucar.edu> 00032 // jgarcia Jose Garcia <jgarcia@ucar.edu> 00033 // jimg James Gallagher <jgallagher@gso.uri.edu> 00034 00035 #ifndef T_BESPlugin_h 00036 #define T_BESPlugin_h 00037 00038 #include <dlfcn.h> 00039 #include <string> 00040 #include <iostream> 00041 00042 #include "BESObj.h" 00043 #include "BESInternalFatalError.h" 00044 #include "BESInternalError.h" 00045 #include "BESDebug.h" 00046 00047 #undef UNPLUG_HANDLERS 00048 00049 using std::string; 00050 using std::cerr; 00051 using std::endl; 00052 00056 class NoSuchLibrary : public BESInternalFatalError 00057 { 00058 public: 00059 NoSuchLibrary( const string &msg, const string &file, int line ) 00060 : BESInternalFatalError( msg, file, line ) {} 00061 }; 00062 00066 class NoSuchObject : public BESInternalFatalError 00067 { 00068 public: 00069 NoSuchObject( const string &msg, const string &file, int line ) 00070 : BESInternalFatalError( msg, file, line ) {} 00071 }; 00072 00093 template<typename M> 00094 class BESPlugin : public BESObj 00095 { 00096 private: 00097 string d_filename; // Library filename 00098 void *d_lib; // Open library handle 00099 00102 BESPlugin() throw(BESInternalError) 00103 { 00104 throw BESInternalError( "Unimplemented method", __FILE__, __LINE__ ); 00105 } 00106 00111 BESPlugin(const BESPlugin &p) throw(BESInternalError) 00112 { 00113 throw BESInternalError( "Unimplemented method.", __FILE__, __LINE__ ); 00114 } 00115 00119 BESPlugin &operator=(const BESPlugin &p) throw(BESInternalError) 00120 { 00121 throw BESInternalError( "Unimplemented method.", __FILE__, __LINE__ ); 00122 } 00123 00124 void *get_lib() throw(NoSuchLibrary) { 00125 if (!d_lib) { 00126 d_lib = dlopen(d_filename.c_str(), RTLD_NOW|RTLD_LOCAL); 00127 BESDEBUG( "bes", "BESPlugin: plug in handler:" << d_filename << ", " << d_lib << endl); 00128 if (d_lib == NULL) { 00129 throw NoSuchLibrary( string( dlerror() ), __FILE__, __LINE__ ) ; 00130 } 00131 } 00132 00133 return d_lib; 00134 } 00135 00136 public: 00141 BESPlugin(const string &filename) : d_filename(filename), d_lib(0) {} 00142 00145 virtual ~BESPlugin() { 00146 BESDEBUG( "bes", "BESPlugin: unplugging handler:" << d_filename << ", " << d_lib << endl); 00147 #ifdef UNPLUG_HANDLERS 00148 if (d_lib) { 00149 dlclose(d_lib); 00150 d_lib = 0; // Added; paranoia. jhrg 00151 } 00152 #endif 00153 } 00154 00161 M* instantiate() throw(NoSuchLibrary, NoSuchObject) { 00162 void *maker = dlsym(get_lib(), "maker"); 00163 if (!maker) { 00164 throw NoSuchObject( string( dlerror() ), __FILE__, __LINE__ ) ; 00165 } 00166 00167 typedef M *(*maker_func_ptr)(); 00168 maker_func_ptr my_maker = *reinterpret_cast<maker_func_ptr*>(&maker); 00169 M *my_M = (my_maker)(); 00170 00171 return my_M; 00172 } 00173 00174 virtual void dump( ostream &strm ) const 00175 { 00176 strm << "BESPlugin::dump - (" << (void *)this << ")" << endl ; 00177 strm << " plugin name: " << d_filename << endl ; 00178 strm << " library handle: " << (void *)d_lib << endl ; 00179 } 00180 }; 00181 00182 #endif // T_BESPlugin_h 00183