desktop/src/dlopen.h

   1 ///
   2 /// \file       dlopen.h
   3 ///             Base class wrapper for dlopen() behaviour
   4 ///             Drawback: only one dlopen'd library per class.
   5 ///
   6
   7 /*
   8     Copyright (C) 2009-2013, Net Direct Inc. (http://www.netdirect.ca/)
   9
  10     This program is free software; you can redistribute it and/or modify
  11     it under the terms of the GNU General Public License as published by
  12     the Free Software Foundation; either version 2 of the License, or
  13     (at your option) any later version.
  14
  15     This program is distributed in the hope that it will be useful,
  16     but WITHOUT ANY WARRANTY; without even the implied warranty of
  17     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  18
  19     See the GNU General Public License in the COPYING file at the
  20     root directory of this project for more details.
  21 */
  22
  23 #ifndef __BARRYDESKTOP_DLOPEN_H__
  24 #define __BARRYDESKTOP_DLOPEN_H__
  25
  26 #include "error.h"
  27 #include <dlfcn.h>
  28 #include <string.h>
  29 #include <string>
  30
  31 //
  32 // DlOpen
  33 //
  34 /// Base class wrapper for dlopen() libraries.  Only handles one
  35 /// library handle at a time.
  36 ///
  37 class DlOpen
  38 {
  39         void *m_handle;
  40
  41 protected:
  42         bool Open(const char *libname);
  43         void Shutdown();
  44
  45         template <class FuncPtrT>
  46         void LoadSym(FuncPtrT &funcptr, const char *symbol)
  47         {
  48                 // work around the warning: ISO C++ forbids casting
  49                 // between pointer-to-function and pointer-to-object
  50                 //funcptr = (FuncPtrT) dlsym(this->m_handle, symbol);
  51
  52                 void *fptr = dlsym(this->m_handle, symbol);
  53                 if( fptr == NULL )
  54                         throw DlError(std::string("Can't load ") + symbol);
  55
  56                 if( sizeof(fptr) != sizeof(FuncPtrT) )
  57                         throw std::logic_error("Platform not supported: sizeof(void*) != sizeof(void (*)())");
  58
  59                 memcpy(&funcptr, &fptr, sizeof(void*));
  60         }
  61
  62 public:
  63         DlOpen();
  64         virtual ~DlOpen();
  65 };
  66
  67 #endif
  68