luabind/handle.hpp

   1 // Copyright (c) 2005 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 #ifndef LUABIND_HANDLE_050420_HPP
  24 #define LUABIND_HANDLE_050420_HPP
  25
  26 #include <luabind/lua_include.hpp>
  27 #include <luabind/value_wrapper.hpp>
  28
  29 namespace luabind {
  30
  31 // A reference to a Lua value. Represents an entry in the
  32 // registry table.
  33 class handle
  34 {
  35 public:
  36     handle();
  37     handle(lua_State* interpreter, int stack_index);
  38     handle(handle const& other);
  39     ~handle();
  40
  41     handle& operator=(handle const& other);
  42     void swap(handle& other);
  43
  44     void push(lua_State* interpreter) const;
  45
  46     lua_State* interpreter() const;
  47
  48     void replace(lua_State* interpreter, int stack_index);
  49
  50 private:
  51     lua_State* m_interpreter;
  52     int m_index;
  53 };
  54
  55 inline handle::handle()
  56   : m_interpreter(0)
  57   , m_index(LUA_NOREF)
  58 {}
  59
  60 inline handle::handle(handle const& other)
  61   : m_interpreter(other.m_interpreter)
  62   , m_index(LUA_NOREF)
  63 {
  64     if (m_interpreter == 0) return;
  65     lua_rawgeti(m_interpreter, LUA_REGISTRYINDEX, other.m_index);
  66     m_index = luaL_ref(m_interpreter, LUA_REGISTRYINDEX);
  67 }
  68
  69 inline handle::handle(lua_State* interpreter, int stack_index)
  70   : m_interpreter(interpreter)
  71   , m_index(LUA_NOREF)
  72 {
  73     lua_pushvalue(interpreter, stack_index);
  74     m_index = luaL_ref(interpreter, LUA_REGISTRYINDEX);
  75 }
  76
  77 inline handle::~handle()
  78 {
  79     if (m_interpreter && m_index != LUA_NOREF)
  80         luaL_unref(m_interpreter, LUA_REGISTRYINDEX, m_index);
  81 }
  82
  83 inline handle& handle::operator=(handle const& other)
  84 {
  85     handle(other).swap(*this);
  86     return *this;
  87 }
  88
  89 inline void handle::swap(handle& other)
  90 {
  91     std::swap(m_interpreter, other.m_interpreter);
  92     std::swap(m_index, other.m_index);
  93 }
  94
  95 inline void handle::push(lua_State* interpreter) const
  96 {
  97     lua_rawgeti(interpreter, LUA_REGISTRYINDEX, m_index);
  98 }
  99
 100 inline lua_State* handle::interpreter() const
 101 {
 102     return m_interpreter;
 103 }
 104
 105 inline void handle::replace(lua_State* interpreter, int stack_index)
 106 {
 107     lua_pushvalue(interpreter, stack_index);
 108     lua_rawseti(interpreter, LUA_REGISTRYINDEX, m_index);
 109 }
 110
 111 template<>
 112 struct value_wrapper_traits<handle>
 113 {
 114     typedef boost::mpl::true_ is_specialized;
 115
 116     static lua_State* interpreter(handle const& value)
 117     {
 118         return value.interpreter();
 119     }
 120
 121     static void unwrap(lua_State* interpreter, handle const& value)
 122     {
 123         value.push(interpreter);
 124     }
 125
 126     static bool check(...)
 127     {
 128         return true;
 129     }
 130 };
 131
 132 } // namespace luabind
 133
 134 #endif // LUABIND_HANDLE_050420_HPP
 135