luabind/detail/ref.hpp

   1 // Copyright (c) 2003 Daniel Wallin and Arvid Norberg
   2
   3 // Permission is hereby granted, free of charge, to any person obtaining a
   4 // copy of this software and associated documentation files (the "Software"),
   5 // to deal in the Software without restriction, including without limitation
   6 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
   7 // and/or sell copies of the Software, and to permit persons to whom the
   8 // Software is furnished to do so, subject to the following conditions:
   9
  10 // The above copyright notice and this permission notice shall be included
  11 // in all copies or substantial portions of the Software.
  12
  13 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
  14 // ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
  15 // TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
  16 // PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
  17 // SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
  18 // ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  19 // ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
  21 // OR OTHER DEALINGS IN THE SOFTWARE.
  22
  23
  24 #ifndef LUABIND_REF_HPP_INCLUDED
  25 #define LUABIND_REF_HPP_INCLUDED
  26
  27 #include <cassert>
  28 #include <algorithm>
  29
  30 #include <luabind/config.hpp>
  31 #include <luabind/lua_include.hpp>
  32
  33 namespace luabind
  34 {
  35
  36 namespace detail
  37 {
  38
  39         struct lua_reference
  40         {
  41                 lua_reference(lua_State* L_ = 0)
  42                         : L(L_)
  43                         , m_ref(LUA_NOREF)
  44                 {}
  45                 lua_reference(lua_reference const& r)
  46                         : L(r.L)
  47                         , m_ref(LUA_NOREF)
  48                 {
  49                         if (!r.is_valid()) return;
  50                         r.get(L);
  51                         set(L);
  52                 }
  53                 ~lua_reference() { reset(); }
  54
  55                 lua_State* state() const { return L; }
  56
  57                 void operator=(lua_reference const& r)
  58                 {
  59                         // TODO: self assignment problems
  60                         reset();
  61                         if (!r.is_valid()) return;
  62                         r.get(r.state());
  63                         set(r.state());
  64                 }
  65
  66                 bool is_valid() const
  67                 { return m_ref != LUA_NOREF; }
  68
  69                 void set(lua_State* L_)
  70                 {
  71                         reset();
  72                         L = L_;
  73                         m_ref = luaL_ref(L, LUA_REGISTRYINDEX);
  74                 }
  75
  76                 void replace(lua_State* L_)
  77                 {
  78                         lua_rawseti(L_, LUA_REGISTRYINDEX, m_ref);
  79                 }
  80
  81                 // L may not be the same pointer as
  82                 // was used when creating this reference
  83                 // since it may be a thread that shares
  84                 // the same globals table.
  85                 void get(lua_State* L_) const
  86                 {
  87                         assert(m_ref != LUA_NOREF);
  88                         assert(L_);
  89                         lua_rawgeti(L_, LUA_REGISTRYINDEX, m_ref);
  90                 }
  91
  92                 void reset()
  93                 {
  94                         if (L && m_ref != LUA_NOREF) luaL_unref(L, LUA_REGISTRYINDEX, m_ref);
  95                         m_ref = LUA_NOREF;
  96                 }
  97
  98                 void swap(lua_reference& r)
  99                 {
 100                         assert(r.L == L);
 101                         std::swap(r.m_ref, m_ref);
 102                 }
 103
 104         private:
 105                 lua_State* L;
 106                 int m_ref;
 107         };
 108
 109 }}
 110
 111 #endif // LUABIND_REF_HPP_INCLUDED
 112