libshevek
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00001 /* refbase.hh - base class for using Glib::RefPtr 00002 * Copyright 2003 Bas Wijnen <wijnen@debian.org> 00003 * 00004 * This program is free software: you can redistribute it and/or modify 00005 * it under the terms of the GNU General Public License as published by 00006 * the Free Software Foundation, either version 3 of the License, or 00007 * (at your option) any later version. 00008 * 00009 * This program is distributed in the hope that it will be useful, 00010 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00012 * GNU General Public License for more details. 00013 * 00014 * You should have received a copy of the GNU General Public License 00015 * along with this program. If not, see <http://www.gnu.org/licenses/>. 00016 */ 00017 00018 #ifndef SHEVEK_REFBASE_HH 00019 #define SHEVEK_REFBASE_HH 00020 00021 #include <sigc++/sigc++.h> 00022 #include <glibmm/refptr.h> 00023 00024 namespace shevek 00025 { 00027 class refbase 00028 { 00029 public: 00031 template <typename _T> Glib::RefPtr <_T> cast_dynamic () 00032 { return Glib::RefPtr <_T>::cast_dynamic (refptr_this <refbase> ()); } 00033 protected: 00035 refbase (); 00037 virtual ~refbase (); 00039 00042 template <typename T> Glib::RefPtr <T> refptr_this (); 00043 private: 00044 // Not copyable 00045 refbase (refbase const &that); 00046 refbase &operator= (refbase const &that); 00047 // Reference functions, needed for Glib::RefPtr. 00048 virtual void reference (); 00049 virtual void unreference (); 00050 // Allow Glib::RefPtr to call the above. 00051 template <typename T> friend class Glib::RefPtr; 00052 // Reference count. 00053 unsigned m_refcount; 00054 }; 00055 00056 template <typename T> 00057 Glib::RefPtr <T> refbase::refptr_this () 00058 { 00059 // This is a bit of a hack, but I don't see a way to solve it otherwise. 00060 // The idea is that members of refbase-derived classes need a refptr to 00061 // their this pointer, to give away. 00062 // The only usable constructor of RefPtr for that purpose is the one which 00063 // is meant for create (). However, that does not increment the reference 00064 // counter. So I do that by hand. 00065 reference (); 00066 return Glib::RefPtr <T> (dynamic_cast <T *> (this) ); 00067 } 00068 } 00069 00070 #endif