include/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 #include <luabind/detail/ref.hpp>
  29
  30 namespace luabind {
  31
  32 // A reference to a Lua value. Represents an entry in the
  33 // registry table.
  34 class handle
  35 {
  36 public:
  37     handle();
  38     handle(lua_State* interpreter, int stack_index);
  39     handle(handle const& other);
  40     ~handle();
  41
  42     handle& operator=(handle const& other);
  43     void swap(handle& other);
  44
  45     void push(lua_State* interpreter) const;
  46
  47     lua_State* interpreter() const;
  48
  49     void replace(lua_State* interpreter, int stack_index);
  50
  51 private:
  52     lua_State* m_interpreter;
  53     int m_index;
  54 };
  55
  56 inline handle::handle()
  57   : m_interpreter(0)
  58   , m_index(LUA_NOREF)
  59 {}
  60
  61 inline handle::handle(handle const& other)
  62   : m_interpreter(other.m_interpreter)
  63   , m_index(LUA_NOREF)
  64 {
  65     if (m_interpreter == 0) return;
  66     detail::getref(m_interpreter, other.m_index);
  67     m_index = detail::ref(m_interpreter);
  68 }
  69
  70 inline handle::handle(lua_State* interpreter, int stack_index)
  71   : m_interpreter(interpreter)
  72   , m_index(LUA_NOREF)
  73 {
  74     lua_pushvalue(interpreter, stack_index);
  75     m_index = detail::ref(interpreter);
  76 }
  77
  78 inline handle::~handle()
  79 {
  80     if (m_interpreter && m_index != LUA_NOREF)
  81         detail::unref(m_interpreter, m_index);
  82 }
  83
  84 inline handle& handle::operator=(handle const& other)
  85 {
  86     handle(other).swap(*this);
  87     return *this;
  88 }
  89
  90 inline void handle::swap(handle& other)
  91 {
  92     std::swap(m_interpreter, other.m_interpreter);
  93     std::swap(m_index, other.m_index);
  94 }
  95
  96 inline void handle::push(lua_State* interpreter) const
  97 {
  98     detail::getref(interpreter, m_index);
  99 }
 100
 101 inline lua_State* handle::interpreter() const
 102 {
 103     return m_interpreter;
 104 }
 105
 106 inline void handle::replace(lua_State* interpreter, int stack_index)
 107 {
 108     lua_pushvalue(interpreter, stack_index);
 109     lua_rawseti(interpreter, LUA_REGISTRYINDEX, m_index);
 110 }
 111
 112 template<>
 113 struct value_wrapper_traits<handle>
 114 {
 115     typedef boost::mpl::true_ is_specialized;
 116
 117     static lua_State* interpreter(handle const& value)
 118     {
 119         return value.interpreter();
 120     }
 121
 122     static void unwrap(lua_State* interpreter, handle const& value)
 123     {
 124         value.push(interpreter);
 125     }
 126
 127     static bool check(...)
 128     {
 129         return true;
 130     }
 131 };
 132
 133 } // namespace luabind
 134
 135 #endif // LUABIND_HANDLE_050420_HPP
 136