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(lua_State* main, 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     lua_rawgeti(m_interpreter, LUA_REGISTRYINDEX, other.m_index);
  67     m_index = luaL_ref(m_interpreter, LUA_REGISTRYINDEX);
  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 = luaL_ref(interpreter, LUA_REGISTRYINDEX);
  76 }
  77
  78 inline handle::handle(lua_State* main, lua_State* interpreter, int stack_index)
  79   : m_interpreter(main)
  80   , m_index(LUA_NOREF)
  81 {
  82     lua_pushvalue(interpreter, stack_index);
  83     m_index = luaL_ref(interpreter, LUA_REGISTRYINDEX);
  84 }
  85
  86 inline handle::~handle()
  87 {
  88     if (m_interpreter && m_index != LUA_NOREF)
  89         luaL_unref(m_interpreter, LUA_REGISTRYINDEX, m_index);
  90 }
  91
  92 inline handle& handle::operator=(handle const& other)
  93 {
  94     handle(other).swap(*this);
  95     return *this;
  96 }
  97
  98 inline void handle::swap(handle& other)
  99 {
 100     std::swap(m_interpreter, other.m_interpreter);
 101     std::swap(m_index, other.m_index);
 102 }
 103
 104 inline void handle::push(lua_State* interpreter) const
 105 {
 106     lua_rawgeti(interpreter, LUA_REGISTRYINDEX, m_index);
 107 }
 108
 109 inline lua_State* handle::interpreter() const
 110 {
 111     return m_interpreter;
 112 }
 113
 114 inline void handle::replace(lua_State* interpreter, int stack_index)
 115 {
 116     lua_pushvalue(interpreter, stack_index);
 117     lua_rawseti(interpreter, LUA_REGISTRYINDEX, m_index);
 118 }
 119
 120 template<>
 121 struct value_wrapper_traits<handle>
 122 {
 123     typedef boost::mpl::true_ is_specialized;
 124
 125     static lua_State* interpreter(handle const& value)
 126     {
 127         return value.interpreter();
 128     }
 129
 130     static void unwrap(lua_State* interpreter, handle const& value)
 131     {
 132         value.push(interpreter);
 133     }
 134
 135     static bool check(...)
 136     {
 137         return true;
 138     }
 139 };
 140
 141 } // namespace luabind
 142
 143 #endif // LUABIND_HANDLE_050420_HPP
 144