diff options
author | Robin Gareus <robin@gareus.org> | 2016-07-18 23:30:20 +0200 |
---|---|---|
committer | Robin Gareus <robin@gareus.org> | 2016-07-18 23:52:40 +0200 |
commit | 520dcf8cdf0e6cf36210fa7826b63fe2c64ec218 (patch) | |
tree | db61180e4c0b65a98ccb502b907ffe56a3ceac11 /libs/lua | |
parent | bb29478aa2739f985cc7d41ae48340a85f0b89cb (diff) |
rework lua-bridge C++ variable references
Since lua functions are closures, C++ methods that pass arguments by
reference cannot be used directly. The previous approach (boost::ref)
failed with clang. Assume the following:
void foo (float&) { }
static inline float& bar () {
boost::reference_wrapper<float> r (42);
return r.get ();
}
foo ( bar () );
With gcc, "r" goes out of scope after foo's arguments are processed
and all is well.
But with clang, "r" already leave scope when *inlined* bar() returns.
Solution: allocate some user-data on the lua-stack to hold the reference.
There is no reference to this user-data so lua will eventually
garbage collect it.
(theoretically, creating the table which holds the return-values
could trigger an emergency garbage collection when memory is low and
free the reference just while they're being pushed to the table, then
gain FuncArgs<Params> already dereferenced them all as variable on the
C stack -- probably again compiler specific)
Diffstat (limited to 'libs/lua')
-rw-r--r-- | libs/lua/LuaBridge/LuaBridge.h | 1 | ||||
-rw-r--r-- | libs/lua/LuaBridge/detail/Stack.h | 53 |
2 files changed, 26 insertions, 28 deletions
diff --git a/libs/lua/LuaBridge/LuaBridge.h b/libs/lua/LuaBridge/LuaBridge.h index 706e77cbfd..01f9e90b7d 100644 --- a/libs/lua/LuaBridge/LuaBridge.h +++ b/libs/lua/LuaBridge/LuaBridge.h @@ -47,7 +47,6 @@ #include <vector> #include <inttypes.h> -#include <boost/ref.hpp> #include <boost/type_traits.hpp> #include <boost/shared_ptr.hpp> diff --git a/libs/lua/LuaBridge/detail/Stack.h b/libs/lua/LuaBridge/detail/Stack.h index 0d4919be27..e6ff637f19 100644 --- a/libs/lua/LuaBridge/detail/Stack.h +++ b/libs/lua/LuaBridge/detail/Stack.h @@ -127,8 +127,8 @@ struct Stack <int &> static inline int& get (lua_State* L, int index) { int l = static_cast <int> (luaL_checknumber (L, index)); - boost::reference_wrapper<int> r (l); - return r.get(); + int* x = new (lua_newuserdata (L, sizeof (int))) int (l); + return *x; } }; @@ -175,8 +175,8 @@ struct Stack <unsigned int &> static inline unsigned int& get (lua_State* L, int index) { unsigned int l = static_cast <unsigned int> (luaL_checknumber (L, index)); - boost::reference_wrapper<unsigned int> r (l); - return r.get(); + unsigned int* x = new (lua_newuserdata (L, sizeof (unsigned int))) unsigned int (l); + return *x; } }; @@ -223,8 +223,8 @@ struct Stack <unsigned char &> static inline unsigned char& get (lua_State* L, int index) { unsigned char l = static_cast <unsigned char> (luaL_checknumber (L, index)); - boost::reference_wrapper<unsigned char> r (l); - return r.get(); + unsigned char* x = new (lua_newuserdata (L, sizeof (unsigned char))) unsigned char (l); + return *x; } }; @@ -271,8 +271,8 @@ struct Stack <short &> static inline short& get (lua_State* L, int index) { short l = static_cast <short> (luaL_checknumber (L, index)); - boost::reference_wrapper<short> r (l); - return r.get(); + short* x = new (lua_newuserdata (L, sizeof (short))) short (l); + return *x; } }; @@ -319,8 +319,8 @@ struct Stack <unsigned short &> static inline unsigned short& get (lua_State* L, int index) { unsigned short l = static_cast <unsigned short> (luaL_checknumber (L, index)); - boost::reference_wrapper<unsigned short> r (l); - return r.get(); + unsigned short* x = new (lua_newuserdata (L, sizeof (unsigned short))) unsigned short (l); + return *x; } }; @@ -367,8 +367,8 @@ struct Stack <long &> static inline long& get (lua_State* L, int index) { long l = static_cast <long> (luaL_checknumber (L, index)); - boost::reference_wrapper<long> r (l); - return r.get(); + long* x = new (lua_newuserdata (L, sizeof (long))) long (l); + return *x; } }; @@ -415,8 +415,8 @@ struct Stack <unsigned long &> static inline unsigned long& get (lua_State* L, int index) { unsigned long l = static_cast <unsigned long> (luaL_checknumber (L, index)); - boost::reference_wrapper<unsigned long> r (l); - return r.get(); + unsigned long* x = new (lua_newuserdata (L, sizeof (unsigned long))) unsigned long (l); + return *x; } }; @@ -463,8 +463,8 @@ struct Stack <long long &> static inline long long& get (lua_State* L, int index) { long long l = static_cast <long long> (luaL_checknumber (L, index)); - boost::reference_wrapper<long long> r (l); - return r.get(); + long long* x = new (lua_newuserdata (L, sizeof (long long))) long long (l); + return *x; } }; @@ -543,8 +543,8 @@ struct Stack <float &> static inline float& get (lua_State* L, int index) { float l = static_cast <float> (luaL_checknumber (L, index)); - boost::reference_wrapper<float> r (l); - return r.get(); + float* x = new (lua_newuserdata (L, sizeof (float))) float (l); + return *x; } }; @@ -588,8 +588,8 @@ template <> struct Stack <double &> static inline double& get (lua_State* L, int index) { double l = static_cast <double> (luaL_checknumber (L, index)); - boost::reference_wrapper<double> r (l); - return r.get(); + double* x = new (lua_newuserdata (L, sizeof (double))) double (l); + return *x; } }; @@ -633,8 +633,8 @@ struct Stack <bool &> { static inline bool& get (lua_State* L, int index) { bool l = lua_toboolean (L, index) ? true : false; - boost::reference_wrapper<bool> r (l); - return r.get(); + bool* x = new (lua_newuserdata (L, sizeof (bool))) bool (l); + return *x; } }; @@ -701,8 +701,8 @@ struct Stack <char &> static inline char get (lua_State* L, int index) { char l = luaL_checkstring (L, index) [0]; - boost::reference_wrapper<char> r (l); - return r.get(); + char* x = new (lua_newuserdata (L, sizeof (char))) char (l); + return *x; } }; @@ -754,8 +754,7 @@ struct Stack <std::string &> { size_t len; const char *str = luaL_checklstring(L, index, &len); - std::string l (str, len); - boost::reference_wrapper<std::string> r (l); - return r.get(); + std::string* x = new (lua_newuserdata (L, sizeof (std::string))) std::string (str, len); + return *x; } }; |