/** Set function environment.
* Sets the table on top of the stack as environment of the function
* at the given stack index.
* @param idx stack index of function
*/
void
LuaContext::setfenv(int idx)
{
#if LUA_VERSION_NUM > 501
// stack: ... func@idx ... env
// find _ENV
int n = 0;
const char *val_name;
while ((val_name = lua_getupvalue(__L, idx, ++n)) != NULL) { // ... env upval
if (strcmp(val_name, "_ENV") == 0) {
// found environment
break;
} else {
// we're not interested, remove value from stack
lua_pop(__L, 1); // ... env
}
}
// found an environment
if (val_name != NULL) { // ... env upval
// create a new simple up value
luaL_loadstring(__L, ""); // ... env upval chunk
lua_pushvalue(__L, -3); // ... env upval chunk env
lua_setupvalue(__L, -2, 1); // ... env upval func
int act_idx = idx > 0 ? idx : idx - 2;
lua_upvaluejoin(__L, act_idx, n, -1, 1); // ... env upval chunk
lua_pop(__L, 3); // ...
} else {
throw Exception("No environment found");
}
#else
lua_setfenv(__L, idx);
#endif
}
static int db_upvaluejoin (lua_State *L) {
int n1 = checkupval(L, 1, 2);
int n2 = checkupval(L, 3, 4);
luaL_argcheck(L, !lua_iscfunction(L, 1), 1, "Lua function expected");
luaL_argcheck(L, !lua_iscfunction(L, 3), 3, "Lua function expected");
lua_upvaluejoin(L, 1, n1, 3, n2);
return 0;
}
int luaT_setfenv52(lua_State *L, int iIndex)
{
int iType = lua_type(L, iIndex);
switch(iType)
{
case LUA_TUSERDATA:
lua_setuservalue(L, iIndex);
return 1;
case LUA_TFUNCTION:
if(lua_iscfunction(L, iIndex))
{
// Our convention: upvalue at #1 is environment
if(lua_setupvalue(L, iIndex, 1) == nullptr)
{
lua_pop(L, 1);
return 0;
}
return 1;
}
else
{
// Language convention: upvalue called _ENV is environment, which
// might be shared with other functions.
const char* sUpName = nullptr;
for(int i = 1; (sUpName = lua_getupvalue(L, iIndex, i)) ; ++i)
{
lua_pop(L, 1); // lua_getupvalue puts the value on the stack, but we just want to replace it
if(std::strcmp(sUpName, "_ENV") == 0)
{
luaL_loadstring(L, "local upv = ... return function() return upv end");
lua_insert(L, -2);
lua_call(L, 1, 1);
lua_upvaluejoin(L, iIndex, i, -1, 1);
lua_pop(L, 1);
return 1;
}
}
lua_pop(L, 1);
return 0;
}
default:
return 0;
}
}
void LuaDebug::UpvalueJoin(int funcindex1, int n1, int funcindex2, int n2) const
{
return lua_upvaluejoin(L(), funcindex1, n1, funcindex2, n2);
}
