1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
#include <iostream>
extern "C"
{
#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"
}
bool dostring(lua_State* L, const char* str)
{
if (luaL_loadbuffer(L, str, std::strlen(str), str) || lua_pcall(L, 0, 0, 0))
{
const char* a = lua_tostring(L, -1);
std::cout << a << "\n";
lua_pop(L, 1);
return true;
}
return false;
}
#include <luabind/luabind.hpp>
#include <boost/intrusive_ptr.hpp>
namespace luabind
{
namespace converters
{
// tell luabind that there is a converter for boost::intrusive_ptr<T>
template<class T>
yes_t is_user_defined(by_value<boost::intrusive_ptr<T> >);
template<class T>
yes_t is_user_defined(by_const_reference<boost::intrusive_ptr<T> >);
// function used to destruct the object in lua
template<class T>
struct decrement_ref_count
{
static void apply(void* ptr)
{
T* p = static_cast<T*>(ptr);
intrusive_ptr_release(p);
}
};
template<class T>
void convert_cpp_to_lua(lua_State* L, const boost::intrusive_ptr<T>& ptr)
{
if (!ptr)
{
lua_pushnil(L);
return;
}
T* raw_ptr = ptr.get();
// add reference to object, this will be released when the object is collected
intrusive_ptr_add_ref(raw_ptr);
detail::class_registry* registry = luabind::detail::class_registry::get_registry(L);
detail::class_rep* crep = registry->find_class(LUABIND_TYPEID(T));
assert(crep != 0 && "You are trying to convert an unregistered type");
// create the struct to hold the object
void* obj = lua_newuserdata(L, sizeof(detail::object_rep));
// we send 0 as destructor since we know it will never be called
new(obj) luabind::detail::object_rep(raw_ptr, crep, detail::object_rep::owner, decrement_ref_count<T>::apply);
// set the meta table
detail::getref(L, crep->metatable_ref());
lua_setmetatable(L, -2);
}
template<class T>
boost::intrusive_ptr<T>
convert_lua_to_cpp(lua_State* L, by_const_reference<boost::intrusive_ptr<T> >, int index)
{
typename detail::default_policy::template generate_converter<T*, detail::lua_to_cpp>::type converter;
T* ptr = converter.apply(L, LUABIND_DECORATE_TYPE(T*), index);
return boost::intrusive_ptr<T>(ptr);
}
template<class T>
boost::intrusive_ptr<T> convert_lua_to_cpp(lua_State* L, by_value<boost::intrusive_ptr<T> >, int index)
{
return convert_lua_to_cpp(L, by_const_reference<boost::intrusive_ptr<T> >(), index);
}
template<class T>
int match_lua_to_cpp(lua_State* L, by_value<boost::intrusive_ptr<T> >, int index)
{
typedef typename detail::default_policy::template generate_converter<T*, detail::lua_to_cpp>::type converter_t;
return converter_t::match(L, LUABIND_DECORATE_TYPE(T*), index);
}
template<class T>
int match_lua_to_cpp(lua_State* L, by_const_reference<boost::intrusive_ptr<T> >, int index)
{
typedef typename detail::default_policy::template generate_converter<T*, detail::lua_to_cpp>::type converter_t;
return converter_t::match(L, LUABIND_DECORATE_TYPE(T*), index);
}
}
}
struct A
{
A()
: cnt(0)
{}
~A() { std::cout << "free memory\n"; }
int cnt;
};
void intrusive_ptr_add_ref(A* ptr)
{
++ptr->cnt;
std::cout << "add ref\n";
}
void intrusive_ptr_release(A* ptr)
{
--ptr->cnt;
std::cout << "release\n";
if (ptr->cnt == 0) delete ptr;
}
void f(boost::intrusive_ptr<A> ptr)
{
std::cout << "count: " << ptr->cnt << "\n";
}
boost::intrusive_ptr<A> factory()
{
return boost::intrusive_ptr<A>(new A());
}
int main()
{
lua_State* L = luaL_newstate();
lua_baselibopen(L);
luabind::open(L);
using namespace luabind;
module(L)
[
class_<A>("A")
.def_readonly("cnt", &A::cnt),
def("factory", &factory),
def("f", &f)
];
dostring(L, "a = factory()");
dostring(L, "print('lua count: ' .. a.cnt)");
dostring(L, "f(a)");
lua_close(L);
return 0;
}
|
